Activation of c-Ki-ras in human gastrointestinal dysplasias determined by direct sequencing of polymerase chain reaction products

Activation of c-Ki-ras by point mutation within exon 1 was studied in 33 specimens of dysplastic gastrointestinal lesions or of cancers presumed to arise from dysplasia. Samples were obtained from patients with underlying ulcerative colitis or Barrett's esophagus, two diseases associated with dysplasia and increased rates of colonic or esophageal adenocarcinoma, respectively. Genomic DNA was amplified using primers bounding this exon in the polymerase chain reaction. Polymerase chain reaction products were analyzed by direct dideoxy sequencing. Three point mutations in codon 13 of c-Ki-ras were found, all in colonic specimens (two high-grade dysplasias and one adenocarcinoma arising in ulcerative colitis). No point mutations were observed in the second exon of c-Ki-ras or in and around codons 12, 13, and 61 of c-N-ras and C-Ha-ras in a partial sampling of the specimens. These data indicate that ras family protooncogene activation is an uncommon event at this level of malignant progression in these disease states. Carcinogenesis in ulcerative colitis and Barrett's esophagus may proceed via different pathways than in sporadic colon cancer, perhaps involving loss or inactivation of suppressor genes.

Esophageal carcinoma-associated proteins detected by two-dimensional polyacrylamide gel electrophoresis

Patterns of proteins of five surgically resected esophageal carcinomas were studied by two-dimensional polyacrylamide gel electrophoresis with silver staining. The samples of normal esophageal mucosa and esophageal carcinoma from the same patient were compared. Each gel had ca. 300 protein spots and had a similar pattern of proteins. Four spots were observed in all of the esophageal carcinomas that were not present in any of the normal mucosae. The molecular weights and isoelectric points were 46,000 and 5.3, 46,000 and 5.2, 36,000 and 4.7 and 33,000 and 5.1, respectively. One spot was observed in all of the normal mucosae but not in any of the esophageal carcinomas. Its molecular weight and isoelectric point were 27,000 and 5.3, respectively.

Cellular distribution of alpha B-crystallin in non-lenticular tissues

alpha B-Crystallin is a subunit of alpha-crystallin, a major protein component of the vertebrate lens. Recently, its expression in various extra-lenticular tissues has been demonstrated by both Western and Northern blotting. In this study, the cellular distribution of alpha B-crystallin in rat organs was examined in detail using immunohistochemistry. Positive reactions were observed in lens, iris, heart, skeletal muscle (type 1 and type 2A fibers), striated muscle in skin and esophagus, Henle's loop and medullary collecting duct of the kidney, Schwann cells of peripheral nerves, glia of the central nervous system, and decidual cells of the placenta. A close correlation with markers of oxidative activity suggests that alpha B-crystallin is expressed in cells that have high levels of oxidative function.

Improved methods for separation of human cytokeratins

The cytokeratins from human bladder and esophageal epithelia were separated using chromatographic techniques. The cytokeratins were first extracted from fresh autopsy tissue using high and low salt buffers. Urea, 8.0-9.5 M, was used to solubilize the resulting cytokeratin pellet. Imidazole was found to increase the solubility of the pellet but reducing agents such as 2-mercaptoethanol were not beneficial. DEAE ion exchange chromatography produced three fractions which were analyzed by using one and two-dimensional electrophoresis. The third fraction was shown to contain the acidic cytokeratins and was further fractionated on a moderately polar reverse phase HPLC column using an acetonitrile elution gradient. Tetramethylammonium tetrafluoroborate was added to the mobile phase to react with any unreacted silanol groups on the stationary phase, and trifluoroacetic acid was added to ion pair with the protein. HPLC fractions of the acidic proteins from human esophagus revealed seven reproducible peaks. All seven peaks were shown by Western blotting to contain an epitope found on cytokeratin 13. The results suggest that the isolation and separation procedures have produced a series of peptide products which all retain a similar epitope but which vary significantly in their hydrophobic characteristics.

Electrophoretic separation of the soluble proteins of different fractions of the sarcocyst of Sarcocystis fusiformis of buffalo (Bubalus bubalis)

The electrophoretic fractionation of the various compounds of the soluble proteins in the cyst wall (CW), cyst fluid (CF) and zoites (ZT) of the sarcocyst of Sarcocystis fusiformis from buffalo (Bubalus bubalis) was studied by polyacrylamide disc gel electrophoresis. The CW fraction was found to contain at least six components, and ZT and CF contained at least four components with varied Rf values. Each gel was subjected to the gel scanner, and the corresponding areas of the peaks along with the percentage of the proteins in the bands were calculated.

Achatin-I, an endogenous neuroexcitatory tetrapeptide from Achatina fulica Férussac containing a D-amino acid residue

A tetrapeptide named achatin-I was purified from the suboesophageal and cerebral ganglia of the African giant snail Achatina fulica Férussac, and evoked a potent neuroexcitatory effect. The amino acid sequence of achatin-I is Gly-D-Phe-Ala-Asp. Achatin-I induced a voltage-dependent inward current, due to Na+, on the identifiable giant neuron, periodically oscillating neuron (PON), of the same snail. All possible isomers of achatin-I were synthesized using the solid-phase method. The sensitivity of the neuron to achatin-I and its isomers was strictly stereospecific; among the various isomers, only achatin-I showed marked effects (ED50 = 2.29 x 10(-6)M), while Gly-D-Phe-D-Ala-Asp, the synthetic D-Ala-isomer, was less than 10(-3) active.

Neuromedin B receptor in esophagus: evidence for subtypes of bombesin receptors

To identify receptors for bombesin-related peptides in the rat esophagus, we measured binding of 125I-Bolton-Hunter neuromedin B (125I-BH-neuromedin B) and 125I-[Tyr4]bombesin to tissue sections from the rat esophagus and compared the results with those for rat pancreas. Esophagus bound both tracers, whereas pancreas bound only 125I-[Tyr4]bombesin. In each tissue binding was saturable, dependent on pH, on time, and on temperature, reversible, and specific. Autoradiography demonstrated binding of both tracers only to the muscularis mucosae of the esophagus and binding of 125I-[Tyr4]bombesin diffusely over pancreatic acini. In the esophagus, the relative potencies for inhibition of binding of both tracers were as follows: neuromedin B greater than bombesin greater than GRP = neuromedin C; similar relative potencies were found for causing contraction of muscle strips from whole esophagus and from the isolated muscularis mucosae. In pancreas tissue sections and dispersed acini, the relative potencies for inhibition of binding of 125I-[Tyr4]bombesin were as follows: bombesin greater than GRP = neuromedin C much greater than neuromedin B. Similar relative potencies were found for stimulation of enzyme secretion from dispersed pancreatic acini. Computer analysis in both tissues demonstrated only a single binding site. The present study demonstrates that rat esophagus muscle possesses specific receptors for bombesin-related peptides. Furthermore, this study shows that the esophageal bombesin receptors represent a previously unidentified class of bombesin receptors in that they have a higher affinity for neuromedin B than for bombesin. In contrast, the pancreatic bombesin receptors have, like all other bombesin receptors described to date, a high affinity for bombesin, but low affinity for neuromedin B.

Expression of hair-related keratins in a soft epithelium: subpopulations of human and mouse dorsal tongue keratinocytes express keratin markers for hair-, skin- and esophageal-types of differentiation

The dorsal surfaces of mammalian tongues are covered with numerous projections known as filiform papillae whose morphology varies in different species. Using a panel of monoclonal antibodies to keratins as probes, we have established that, in both human and mouse, the interpapillary epithelia express mainly the "esophageal-type" keratins, while the papillary epithelia express "skin-type" keratins as well as some keratins reacting with a monoclonal antibody (AE13) to hair keratins. The AE13-reactive proteins of the mouse were found to be very similar to those of authentic mouse hair keratins. However, the corresponding protein of human tongue appears to be different from all known human keratins. This protein has a MW of 51K; it is relatively acidic; it is sulfhydryl-rich, as revealed by iodoacetic acid-induced charge and apparent size shift; it shares an epitope with all the known acidic human hair keratins; and it is associated with keratin fibrils in vivo. This protein may therefore be regarded as a novel type I "hard" keratin. These data establish that mammalian dorsal tongue epithelia can be divided into at least three compartments that undergo mainly "esophageal-", "skin-" and "hair"-types of differentiation. Different keratin filaments, e.g., those of the esophageal- and hair-types, exhibit strikingly different degrees of lateral aggregation, which can potentially account for the different physical strength and rigidity of various cellular compartments. Our data also suggest the possibility that variations in papillary structure in human and mouse may arise from different spatial arrangements of specific keratinocytes, and/or from the expression of specialized hair-related keratins.

Covalent DNA damage in tissues of cigarette smokers as determined by 32P-postlabeling assay

Covalent DNA addition products (adducts) formed by the reaction of chemical carcinogens or their metabolites with DNA are critically involved in the initiation of chemical carcinogenesis and may serve as molecular markers and dosimeters for environmental carcinogen exposures. Using a highly sensitive 32P-postlabeling assay for DNA adduct analysis, we studied DNA damage elicited by cigarette smoke in tissues of smokers. A multitude of characteristic smoking-induced, presumably aromatic DNA adducts were found to occur in a dose- and time-dependent manner in the lung, bronchus, and larynx of smokers with cancer of these organs and to decline only slowly after cessation of smoking. Low levels of adducts appeared to persist for up to 14 years in the lungs of exsmokers with high previous exposures. These results corroborate data of epidemiological studies showing that the lung cancer risk and mortality of smokers increase with the intensity and duration of smoking and decline only slowly after cessation of smoking. Tissue distribution studies in autopsy samples revealed the presence of smoking-associated DNA lesions also in the kidney, bladder, esophagus, heart, ascending aorta, and liver. The most extensive DNA damage was found in lung and heart, i.e., 1 aromatic adduct in about 10(7) DNA nucleotides. Our results suggest that cigarette smoking-induced DNA adduct formation is causally related to cancer in the target organs.

Severe destruction of esophageal nerves in a patient with achalasia secondary to gastric cancer. A possible role of eosinophil neurotoxic proteins

We present a case of secondary achalasia due to an adenocarcinoma of the stomach with no tumor infiltration of the esophagus. Immunohistochemical staining revealed a massive infiltration of activated eosinophils in the muscularis of the esophagus with secretion of the highly cytotoxic and neurotoxic eosinophil cationic protein (ECP). Immunohistochemical staining for the neuropeptides VIP and substance P, as well as the histochemical demonstration of AChE, revealed a nearly total absence of all three neurotransmitters/modulators compared to control. The hypothesis is advanced that eosinophil neurotoxicity is the cause of secondary achalasia.

Expression pattern of two related cystic fibrosis-associated calcium-binding proteins in normal and abnormal tissues

This paper reports further study of the identity and function of a protein shown to be elevated in serum from cystic fibrosis (CF) patients and clinically normal heterozygotes. Monoclonal antibodies, specifically recognizing the tentatively named cystic fibrosis antigen (CFAg), were produced. Immunoaffinity purification of CFAg from several sources revealed two components: 11 x 10(3) and 14 x 10(3) Mr protein. cDNA clones corresponding to each protein have been isolated. Data-base comparisons of the deduced amino acid sequences suggest that both genes encode related but distinct calcium-binding proteins. We propose the name calgranulin A and B, for the 11 x 10(3) and 14 x 10(3) Mr components, respectively. It is clear from the assignment of the calgranulin genes to chromosome 1 that neither is the product of the mutant CF gene, which maps to chromosome 7. We have used the monoclonal antibodies to study the tissue distribution of the two proteins in a wide-ranging immunohistological survey. Where possible the pattern of expression was confirmed by RNA blot analysis. Strong calgranulin expression in granulocytes was confirmed. In addition to myeloid cells, a restricted subset of normal stratified squamous epithelia were found to be calgranulin-positive. These included tongue, oesophagus and buccal cells, the last of which has been shown to have altered calmodulin activity in CF patients. Using indirect alkaline phosphatase staining, tissue sections of lung, pancreas and skin (normally considered sites where the CF defect is expressed) were not calgranulin-positive. However, by indirect immunofluorescence, nasal polyp sections showed weak patchy calgranulin expression in some epithelial cells, and stronger, higher frequency expression when such cells were briefly cultured.(ABSTRACT TRUNCATED AT 250 WORDS)

Gas chromatographic/mass spectrometric quantitative analysis of eicosanoids in human oesophageal mucosa

In order to investigate the contribution of eicosanoids to human oesophageal functions and disorders (gastrooesophageal reflux, GOR and reflux oesophagitis, RO), we have used a selected ion monitoring gas chromatographic/mass spectrometric methodology to quantify the cyclooxygenase and lipoxygenase products biosynthesized in vitro by endoscopic mucosal biopsy specimens. Prostaglandins (PGs) were quantified as MEMOTMS derivatives and HETEs, as hydrogenated methyl ester of tert-butyldimethylsilyl) ether derivatives. PGE2, PGF2 alpha appeared as the major prostanoids, whereas 12HETE seemed to be the major lipoxygenase product. In the case of GOR or RO, biosynthesis of PGE2 was dramatically increased, while no change could be detected for 12HETE. PGE2 increase seems to be related to inflammatory reaction, in which its exact role remains unclear. Moreover, it cannot be excluded that PGE2 is a side product which might be protective to the oesophageal mucosa.

Novel protein in human epidermal keratinocytes: regulation of expression during differentiation

Recently, two groups of cDNA clones have been isolated from human epidermal keratinocytes; the clones correspond to genes whose expression is stimulated by exposure of the cells to UV light or treatment with 4-nitroquinoline 1-oxide or 12-O-tetradecanoylphorbol 13-acetate (T. Kartasova and P. van de Putte, Mol. Cell. Biol. 8:2195-2203, 1988). The proteins predicted by the nucleotide sequence of both groups of cDNAs are small (8 to 10 kilodaltons), are exceptionally rich in proline, glutamine, and cysteine, and contain repeating elements with a common sequence, PK PEPC. These proteins were designated sprI and sprII (small, proline rich). Here we describe the characterization of the sprIa protein, which is encoded by one of the group 1 cDNAs. The expression of this protein during keratinocyte differentiation in vitro and the distribution of the sprIa protein in some human tissues was studied by using a specific rabbit antiserum directed against a synthetic polypeptide corresponding to the 30 amino acids of the C-terminal region of the sprIa gene product. The results indicate that the expression of the sprIa protein is stimulated during keratinocyte differentiation both in vitro and in vivo.

Intracytoplasmic plasma proteins in distended esophageal squamous cells (balloon cells)

Esophageal mucosal biopsy specimens frequently show numerous distended squamous cells with pale cytoplasm, which we term "balloon cells." These cells often occur in clusters, have a patchy distribution, and predominate in the prickle-cell layer in biopsies from patients with gastroesophageal reflux. We studied the immunohistochemical characteristics of balloon cells and their associated clinical findings. We demonstrated by immunoperoxidase technique that balloon cells contain intracytoplasmic albumin and immunoglobulin light chains and show reduced staining for keratin, suggesting cellular injury with resultant uptake of plasma proteins and fluid. Balloon cells were absent or sparse in esophageal mucosal biopsy specimens from 12 normal control persons, but were observed in 7 of 10 patients (70%) with gastroesophageal reflux confirmed by pH-probe test (P = 0.001 versus normal controls), in 16 of 25 patients (64%) with clinically suspected reflux (P less than 0.001), and in 4 of 5 patients with infectious or chemotherapy-associated esophagitis. However, no consistent association was found between balloon cells and the presence of the usual histopathologic criteria for epithelial injury, such as increased height of vascular tufts or width of basal zone. We conclude that balloon cells are most commonly observed in biopsy specimens from patients with various causes of esophageal injury. We propose that balloon cells may be a marker for epithelial injury, possibly even when other histopathologic criteria for injury are absent.

Expression of simple epithelial type cytokeratins in stratified epithelia as detected by immunolocalization and hybridization in situ

Multi-layered ("stratified") epithelia differ from one-layered ("simple") polar epithelia by various architectural and functional properties as well as by their cytoskeletal complements, notably a set of cytokeratins characteristic of stratified tissue. The simple epithelial cytokeratins 8 and 18 have so far not been detected in any stratified epithelium. Using specific monoclonal antibodies we have noted, in several but not all samples of stratified epithelia, including esophagus, tongue, exocervix, and vagina, positive immunocytochemical reactions for cytokeratins 8, 18, and 19 which in some regions were selective for the basal cell layer(s) but extended into suprabasal layers in others. In situ hybridization with different probes (riboprobes, synthetic oligonucleotides) for mRNAs of cytokeratin 8 on esophageal epithelium has shown, in extended regions, relatively strong reactivity for cytokeratin 8 mRNA in the basal cell layer. In contrast, probes to cytokeratin 18 have shown much weaker hybridization which, however, was rather evenly spread over basal and suprabasal strata. These results, which emphasize the importance of in situ hybridization in studies of gene expression in complex tissues, show that the genes encoding simple epithelial cytokeratins can be expressed in stratified epithelia. This suggests that continual expression of genes coding for simple epithelial cytokeratins is compatible with the formation of squamous stratified tissues and can occur, at least in basal cell layers, simultaneously with the synthesis of certain stratification-related cytokeratins. We also emphasize differences of expression and immunoreactivity of these cytokeratins between different samples and in different regions of the same stratified epithelium and discuss the results in relation to changes of cytokeratin expression during fetal development of stratified epithelia, in response to environmental factors and during the formation of squamous cell carcinomas.

Distribution of pancreatic polypeptide-like immunoreactivity in rat tissues

The distribution of pancreatic polypeptide (PP)-like immunoreactivity (LI) in rat tissue was determined by a specific radioimmunoassay (RIA) after extraction with boiling 1 N acetic acid. The concentration of PP-LI in the ventral area of the pancreas (0.917 +/- 0.106 micrograms/g tissue) was about 10 times greater than that in the dorsal area of the pancreas (0.085 +/- 0.006 micrograms/g tissue). Extrapancreatic PP-LI was present in the colon (0.034 +/- 0.010 micrograms/g tissue) and rectum (0.019 +/- 0.001 micrograms/g tissue). The remainder of the gastrointestinal tract, the lung, kidney, liver, spleen, heart, adrenal gland, and central nervous system contained no measurable PP-LI. Reverse-phase high performance liquid chromatography analysis of the PP-LI materials from the pancreas, colon, and rectum revealed one peak which corresponds to the rat PP standard, under conditions of elution which clearly separated PP, NPY, PYY. These results show that distribution of PP-LI in the rat is different from other known distributions in the PP family of peptides.

Comparison of stationary vs ambulatory 24-hour pH monitoring recording systems

Twenty-four-hour pH monitoring of the esophagus is frequently performed to assess gastroesophageal reflux. We performed a prospective study to determine if results obtained from stationary and ambulatory pH recording systems are comparable. Two groups of patients were studied. Group I consisted of 12 patients monitored simultaneously by both a stationary and an ambulatory pH recording system, each system having a separate pH and reference electrode. In group II, in order to eliminate electrode variability, 10 patients were monitored simultaneously with both systems and a common single pH and reference electrode. In group I, significant correlations were found in six reflux parameters measured and in the 24-hr composite score (r greater than or equal to 0.8722). However, in three of the 12 patients, marked discrepancies were noted in the composite score calculated by the stationary and ambulatory recording systems. Small variations in the pH level recorded by different pH electrodes may have accounted for the discrepancies. In group II, where electrode variability was eliminated, a better correlation was noted between all parameters measured (r greater than or equal to 0.991), and no discrepancies were noted between calculated composite scores. We concluded that the stationary and ambulatory recording systems tested are comparable in measuring 24-hr esophageal pH.

Immunohistochemical distribution of hepatic fatty acid-binding protein in rat and human alimentary tract

Tissues from rat and human alimentary tract were immunostained with rabbit antibodies to fatty acid-binding protein (FABP) isolated from rat liver, since the precise immunohistochemical localization of the protein in gut has not been determined. The results obtained indicated that FABP immunoreactivity was found almost exclusively in intestinal absorptive cells, the sole exception being its presence in the cytoplasm of a few goblet cells. In small bowel, FABP-positive cells were most often found in the upper and middle segments, and less frequently in the lower to terminal portion. Immunoreactive cells were also found in large bowel of rat and human, but with differing patterns of distribution. In rat, positive cells were found mainly in the lower portion of the large intestine, whereas in human positive cells were present in all portions. Immunoreactive cells were detected in rat and human cecum, in the upper half of human rectum, and in human vermiform appendix. No such cells were found in esophageal and nonmetaplastic gastric mucosa or in pancreatic tissue, whereas they were present in great numbers in metaplastic gastric mucosa. The results of this study therefore suggest that FABP is a useful marker for research into the physiology or pathology of absorptive cells in the gastrointestinal tracts of both species.

Somatostatin modulation of neurally mediated pepsinogen secretion from frog esophageal mucosa

Frog esophageal mucosa contains peptic glands which are innervated by cholinergic neurons. When incubated in a medium containing 1.5 mM CaCl2, pepsinogen release from esophageal mucosa was increased by a high potassium concentration (55 mM KCl), 1,1-dimethyl-4-phenylpiperazinium (DMPP) or bethanechol. Whereas the response to bethanechol remained little changed, the response to high KCl concentrations or DMPP was abolished in the absence of Ca2+. The stimulatory effects of high KCl concentrations and DMPP were also eliminated by the presence of atropine or somatostatin. Furthermore, pepsinogen release in response to bethanechol was dose-dependently inhibited by somatostatin. Frog esophagus was found to contain somatostatin-like immunoreactivity, with a higher density at the end adjacent to the stomach. Chromatography of mucosa extract on Sephadex G-50 revealed a single peak of somatostatin-like immunoreactivity that coeluted with somatostatin-14. Immunohistochemical staining of the mucosa with peroxidase antiperoxidase technique demonstrated the presence of two varieties of somatostatin-like immunoreactivity-containing cells, one individually dispersed within the intercalated septa and the other in groups within the interlobular septa of the peptic glands. These results seem to indicate that somatostatin or somatostatin-like immunoreactivity may play a modulatory role in neurally mediated pepsinogen secretion in the frog esophagus.

[Dynamics of amino acid and protein metabolism of laying hens after administration of 15N-labeled wheat protein. 7. Incorporation into the amino acids and peptides of the gastrointestinal tract and the pancreas]

In a 15N labelling experiment 12 colostomized laying hens received 15N labelled wheat with 14.37 atom-% 15N excess (15N') over 4 days. 3 hens each were butchered after 12 h, 36 h, 60 h and 108 h after the last 15N' application. The gastro-intestinal tract was divided into 3 parts (oesophagus with crop and gizzard as well as glandular stomach, small intestine, large intestine). These parts and the pancreas were hydrolysed with 6 N HCl and the individual basic as well as the sum of acid and neutral amino acids were determined in the hydrolysed fractions. In addition, the amino acids and peptides were determined in the TCA soluble N fraction. The atom-% 15N' was determined in the individual amino acid and peptide fractions. The labelling of the basic amino acids in the individual tract segments was lower than in the acid and neutral amino acids. In comparison to the peptides, a higher atom-% 15N' could be determined in the free amino acids.

Localization of galanin immunoreactivity in the opossum esophagus

Galanin-like immunoreactivity was studied at 7 levels of the opossum esophagus, lower esophageal sphincter (LES) and adjacent portion of the stomach by indirect immunofluorescence; it was restricted to nervous structures. The majority of myenteric and submucous neurons were galanin-positive and received positive axo-somatic terminations. They also sent out axons staining positively. Galanin-positive fibers and a few atypically located neurons formed a mucous plexus at the bases of mucous glands. Varicose galanin fibers innervated the muscularis mucosae, circular and longitudinal muscle layers, while thick fascicles traversed the muscularis mucosae and circular muscle, possibly interconnecting the myenteric, submucous and mucous plexuses. Galanin-positive fibers did not supply blood vessels. There was no obvious gradient of innervation density along the esophagus, but the sphincter appeared to be more densely innervated than the esophageal body. There was no galanin-positive input to striated muscle. In view of its widespread distribution, this neuropeptide may serve multiple functions in the esophagus.

A histochemical study of the mucins in the digestive tract of the chicken

Little is known about the distribution of glycoproteins in the digestive tube of birds. In the present study, the localization and distribution of mucins in the digestive tract of the chicken are reported. Sialo- and sulpho-mucins were widely distributed throughout the chicken digestive tube. Some of the mucous cells of the proximal segment of the proventriculus presented neutral glycoproteins; in the medial segment, surface cells containing only sialo-mucins were observed. Surface cells of the gizzard contained both sialo- and sulpho-mucins while PAS-positive material was localized in the lumen of the glands. 2 types of mucous cells were observed in the small intestine; 1 type contained only sialo-mucins and the other contained both sialo- and sulpho-mucins. In the large intestine and caecum, both types of acid mucins were present in the mucous cells. In conclusion, the distribution of glycoproteins in the chicken reported in the present study show marked differences with that reported in other avian species.

Glycoconjugate expression in normal, metaplastic, and neoplastic human upper gastrointestinal mucosa

Glycoconjugate structure in upper gastrointestinal epithelium was studied using five lectins to determine the relationship between aberrant differentiation and glycoconjugate expression. Specimens of normal esophagus, stomach, and duodenum were examined and compared with specimens of columnar metaplasia in the esophagus (Barrett's esophagus) and specimens of adenocarcinoma of the esophagus and stomach. Specific terminal glycoconjugate structures were found for the esophagus, stomach, and duodenum. Minor differences were found between the antral and fundic gland mucosae, reflecting their respective cell populations. In biopsies of Barrett's esophagus, gastric-type columnar metaplasia expressed glycoconjugates indistinguishable from those in the normal stomach. In specialized-type columnar metaplasia, a more restricted expression of glycoconjugates was seen resembling the normal duodenum. The presence of low grade dysplasia in Barrett's esophagus associated with adenocarcinoma had no impact on glycoconjugate expression. However, a distinctive difference in glycosylation was seen in high grade dysplasia of the columnar-lined esophagus and in adenocarcinoma of the esophagus and stomach. Barrett's esophagus is a morphological mosaic in which the glycoconjugate expression resembles that seen in the normal stomach and duodenum. However, in high grade dysplasia and carcinoma, variable deletion of glycoconjugate expression can be found.

Distributions of neuropeptides in the human esophagus

The distributions of nerve cells and fibers with immunoreactivity for the peptides substance P, somatostatin, enkephalin, vasoactive intestinal peptide, gastrin-releasing peptide, and neuropeptide Y and the enzyme tyrosine hydroxylase were examined in 25 samples of human esophagus. These were compared with samples of stomach and intestine. In the smooth muscle of the muscularis externa, the muscularis mucosae, and beneath the epithelium, the most abundant nerve fibers contained vasoactive intestinal peptide and neuropeptide Y, in contrast to the scarcity of substance P, enkephalin, somatostatin, and gastrin-releasing peptide. Gastric and intestinal samples contained dense populations of fibers containing vasoactive intestinal peptide, neuropeptide Y, substance P, and enkephalin in the equivalent layers, but somatostatin- and gastrin-releasing peptide-immunoreactive fibers were scarce. Complete coexistence of vasoactive intestinal peptide and neuropeptide Y in nerve fibers within the muscle layers was demonstrated in the esophagus, but not in gastric and intestinal samples. The myenteric plexus along the length of the esophagus contained cell bodies and fibers reactive for vasoactive intestinal peptide, neuropeptide Y, enkephalin, and substance P. Somatostatin-immunoreactive cell bodies were very rare in the myenteric plexus, no gastrin-releasing peptide-immunoreactive cell bodies were seen, and both somatostatin and gastrin-releasing peptide-immunoreactive fibers were rare. In the upper esophagus, striated muscle bundles did not contain nerve fibers reactive for these peptides but immunoreactive fibers were seen in the muscularis mucosae and subepithelium. It is concluded that the esophagus has a different pattern of innervation by peptide-containing neurons than the stomach and intestines. Esophageal neurons can be classified into separate classes on the basis of their peptide content.

DNA content in Barrett's esophagus and esophageal malignancy

Barrett's esophagus is a premalignant condition; endoscopic surveillance is often performed to search for early adenocarcinoma of the esophagus. In an attempt to detect early changes of malignancy, we have added the use of flow cytometry to routine endoscopic surveillance procedures. DNA histograms were generated from biopsy samples by utilizing a specific DNA fluorochrome (4',6-diamidino-2-phenylindole) and flow cytometry. Sixty-three samples from patients with esophagitis, Barrett's esophagus, and esophageal malignancy were analyzed. An abnormal DNA histogram (aneuploidy) was detected in 79% of esophageal malignancies. In addition, aneuploidy was detected in seven patients with Barrett's esophagus, two of whom had dysplasia. DNA quantification with flow cytometry may be a useful adjunct in screening patients with Barrett's esophagus for early malignant change.

Esophageal collagen content and mechanical strength after endoscopic sclerotherapy of esophageal varices. An experimental study in rabbits

Twenty-five rabbits with esophageal varices were randomized to no treatment (n = 10) or endoscopic paravenous sclerotherapy of the varices (n = 15). Five other rabbits served as sham-operated controls. When they were killed, the mechanical strength and collagen content of the esophagus were determined at proximal, middle, and distal levels. The esophagus was examined histologically at proximal and distal levels. Animals treated by sclerotherapy showed histologic edema and inflammation of the esophageal wall after 2 days. This was not accompanied by any decrease in collagen content or mechanical strength. Ten days after sclerotherapy a slight but non-significant increase in collagen content and mechanical strength at middle and distal levels was observed. After 30 days the increase in collagen content at middle and distal levels was significant, and the mechanical strength was significantly increased at the middle level.

Intramural distribution of Met5-enkephalin-Arg6-Gly7-Leu8 in sphincter regions of the human gut

The intramural distribution of Met5-enkephalin-Arg6-Gly7-Leu8 (MERGL) was studied in the oesophago-cardiac, pyloric, ileo-caecal and sigmoid-recto-anal regions of the human digestive tract. Serial samples encompassing each area were separated into mucosa, submucosa and muscularis externa and extracted for radioimmunoassay. Comparatively low levels of MERGL immunoreactivity were measured throughout the cardiac junction. Conversely, a remarkable peak of MERGL concentration was detected at the pyloric junction, in both submucosa and muscularis. A progressive decrease in tissue levels of the same peptide, most evident in the submucosa, was detected on the proximal side of the ileo-caecal region. In the distal sigmoid colon and rectum MERGL concentrations showed a rapid decline, down to very low levels in the anal canal. The results may suggest the involvement of an enkephalinergic mechanism in the control of the human pylorus.

A quantitative study on the distribution of asbestos bodies in extrapulmonary organs

We made a quantitative study of the distribution of asbestos bodies (ABs) in 13 extrapulmonary organs. We selected 26 male subjects and subdivided them into three groups: Group I had 10(2) to less than 10(3) ABs per gram of wet tissue in their lungs; group II had 10 to 99 ABs; and group III had no ABs. In group I, one or more ABs were identified in at least 6 (53.8%) of the examined extrapulmonary organs. In group II, 23.7% of the examined organs had one or more ABs. In group III, no ABs were found. These results seem to indicate that with modest exposure in the lung, the other organs are often exposed to asbestos with some degree. Moreover, the number of AB in the esophagus was significantly larger than that in 9 of the other 12 organs in group I. The pancreas and the spleen were also supposed to be more preferential sites of exposure. However, the relationship between exposure and its effects in extrapulmonary organs remains to be elucidated.

Increased vitamin A in esophagus and other extrahepatic tissues after chronic ethanol consumption in the rat

In rats fed ethanol (36% of total energy) for 1 month, vitamin A content of the esophageal mucosa was found to be increased 5-fold, compared to animals pair-fed an isocaloric control diet containing the same amount of vitamin A. Similar results were observed with diets of either lower vitamin A content or zinc supplementation. Significant increases of retinoids were also found in lungs, trachea, kidneys, and testes, but not in the eyes. These increases in extrahepatic tissues contrasted strikingly with the concomitant decrease in the liver and suggests that chronic ethanol consumption may be associated with some mobilization of vitamin A from the liver to other organs.

[O6-methyldeoxyguanosine in DNA of the adjacent epithelium in human esophageal cancer in Linxian County]

Radioimmunoassay of monoclonal antibodies against O6-methyldeoxyguanosine (O6-MedG) was used to detect the presence of these DNA adducts in the human esophageal epithelium. The analysis comprised 48 adjacent epithelial specimens of the esophageal and cardiac cancer resected in Linxian County and 30 specimens of the fetal esophageal epithelium and 4 of the normal esophageal epithelium from autopsy as collected from the hospital in Beijing. The results show that O6-MedG was detected in all the specimens from the esophageal and cardiac cancer patients. In 7 samples in the adjacent epithelium of esophageal cancer, the level of O6-MedG ranged from 0.5 to 1.0 pmol/mgDNA. 19 showed higher levels up to 37.4 pmol/mgDNA with a mean of 4.72 +/- 6.08 pmol/mgDNA. 5 samples of gastric mucosa showed the level of O6-MedG ranging 0.3-1.0 pmol/mgDNA and the remaining 6 showed a higher level of 1.2-13.4 pmol/mgDNA. The mean was 3.31 +/- 3.97. In all the 11 patients, O6-MedG was detected in the para-cancerous gastric mucosa of the cardiac cancer. 4 normal autopsied esophageal epithelial samples were too low for detection. Samples from the fetal esophageal epithelium showed lower level of O6-MedG, the mean was 0.4 +/- 0.57 pmol/mgDNA. The results mentioned above give us the new evidence that the effect of N-nitrosamines is most likely a causative factor in the carcinogenesis of human esophageal cancer.

Aminoalkylsilane-treated glass slides as support for in situ hybridization of keratin cDNAs to frozen tissue sections under varying fixation and pretreatment conditions

Attempts to investigate the cellular localization of keratin mRNAs by in situ hybridization with specific [35S]-labelled cDNA probes to mouse epithelia have been seriously impeded by the uncontrollable detachment of frozen tissue sections on conventionally coated glass slides (i.e. those coated with egg white, gelatin, collagen). Similarly, a variety of other coating and attachment devices have proved to be unsatisfactory or impracticable for large scale investigations. These difficulties were completely overcome and in situ hybridization was possible after a short immersion of the glass slides in a 2% solution of 3-aminopropyltriethoxysilane in acetone. This treatment provides the glass surface with aminoalkyl groups which are apparently able to react covalently with aldehyde or ketone functions of frozen tissue sections. The resulting firm adhesion of the sections enabled us to investigate the influence of different fixation and prehybridization procedures on the quality of the in situ hybridization. It was found that especially harsh prehybridization, involving hydrochloric acid, heat and proteinase K treatment, drastically reduces the morphological integrity of the sections, thus rendering a reliable assignment of the label difficult. In contrast, a mild prehybridization, consisting mainly of a rehydration of the sections in phosphate-buffered saline and equilibration in 0.1 M glycine, leaves the morphology intact and leads to a highly efficient and specific in situ hybridization.

Healing of esophagojejunal anastomoses after experimental total gastrectomy. A comparative study using manually sutured or stapled anastomoses

In construction of the eosphagojejunostomy after total gastrectomy, the EEA stapled (US Surgical Corporation, Norwalk, CT) and the two-layer interrupted 3-0 Dexon anastomoses are compared concerning the radiological appearance, breaking strength, circulation, and collagen concentration. Thirty female pigs were used. After total gastrectomy and Roux-en-Y preparation, the pigs were randomized to achieve sutured or stapled anastomoses. 141Ce-labeled microspheres were used for measurements of anastomotic blood flow. After the pigs were killed, the breaking strength of the anastomosis was recorded, the collagen content determined, and an anastomotic index calculated comparing two perpendicular diameters in the anastomosis and 5 cm above. Breaking strength, leakage frequency, and anastomotic index were the same in the two groups. One week after surgery, there was a significant increase in anastomotic circulation (p less than 0.05) in both the sutured and the stapled anastomoses compared to controls. Collagen increased equally with time in the two groups (p less than 0.01). The stapled esophagojejunostomy was faster to perform (20 min) than the sutured (28 min) (p less than 0.05).

Pararosaniline or acriflavine-Schiff staining of epoxy embedded tissue after periodic acid oxidation in ethanol: a method suitable for morphometric and fluorometric analysis of glycogen

A method for preparing tissue sections for automatic image analysis of glycogen is described. Large semithin sections of epoxy embedded tissue fixed in glutaraldehyde-osmium were stained with Schiff reagent and acriflavine (fluorescent staining) after resin removal and periodic acid oxidation in ethanol. We found it essential to avoid tissue rehydration before final staining. The Schiff stain permits an assessment of the cellular volume of glycogen, and the acriflavine allows a fluorometric evaluation of glycogen density.

Variation and frequency of cytokeratin polypeptide patterns in human squamous non-keratinizing epithelium

The squamous non-keratinizing epithelium of the human upper digestive tract was analyzed for keratin-like cytoskeletal proteins (cytokeratins) by both high resolution one- and two-dimensional gel electrophoresis. The Triton/high salt-insoluble portion of pure epithelial homogenates contains a number of SDS- and urea-extractable polypeptides, whose two-dimensional gel pattern (NEpHG/SDS) typically represents a defined subset of human cytokeratins. The cytoskeletal preparations of epithelial tissue samples obtained from different individuals were found to be uniform with respect to their content of cytokeratin polypeptides 55.0 kD/basic, 52.0 kD/acidic, and 49.0 kD/acidic. However, we have observed that four basic members of apparent molecular weight 60.0, 59.0, 56.5, and 56.0 kD occur at an inconstant rate. Consequently, the cytokeratin polypeptide patterns appeared highly variable as a result of the presence of constant plus compositionally different subsets of inconstant members. From the analysis of cytoskeletal portions of more than 300 individual tissue samples we demonstrate eight different keratin-like polypeptide patterns including their frequencies and propose the existence of no more than nine. These, most probably, encompass all the possible inter-individual variations to which the cytokeratins of this type of epithelium will combine for forming intermediate-sized filaments in vivo. We furthermore hypothesize that the observed variation of cytokeratin patterns may reflect a polymorphism of genes coding for the variable keratin-like polypeptide members.

Intermediate filaments in non-neuronal cells of invertebrates: isolation and biochemical characterization of intermediate filaments from the esophageal epithelium of the mollusc Helix pomatia

To screen invertebrate tissues for the possible expression of intermediate filaments (IFs), immunofluorescence microscopy with the monoclonal antibody anti-IFA known to detect all mammalian IF proteins was used (Pruss, R. M., R. Mirsky, M. C. Raff, R. Thorpe, A. J. Dowding, and B. H. Anderton. 1981. Cell, 27:419-428). In a limited survey, the lower chordate Branchiostoma as well as the invertebrates Arenicola, Lumbricus, Ascaris, and Helix pomatia revealed a positive reaction primarily on epithelia and on nerves, whereas certain other invertebrates appeared negative. To assess the nature of the positive reaction, Helix pomatia was used since a variety of epithelia was strongly stained by anti-IFA. Fixation-extraction procedures were developed that preserve in electron micrographs of esophagus impressive arrays of IFs as tonofilament bundles. Fractionation procedures performed on single cell preparations document large meshworks of long and curvilinear IF by negative stain. These structures can be purified. One- and two-dimensional gels show three components, all of which are recognized by anti-IFA in immunoblotting: 66 kD/pl 6.35, 53 kD/pl 6.05, and 52 kD/pl 5.95. The molar ratio between the larger and more basic polypeptide and the sum of the two more acidic forms is close to 1. After solubilization in 8.5 M urea, in vitro filament reconstitution is induced when urea is removed by dialysis against 2-50 mM Tris buffer at pH 7.8. The reconstituted filaments contain all three polypeptides. The results establish firmly the existence of invertebrate IFs outside neurones and demonstrate that the esophagus of Helix pomatia displays IFs which in line with the epithelial morphology of the tissue could be related to keratin IF of vertebrates.

Metabolism of benzo[a]pyrene on the nasal mucosa of Syrian hamsters: comparison to metabolism by other extrahepatic tissues and possible role of nasally produced metabolites in carcinogenesis

The formation of metabolites of nasally instilled benzo[a]pyrene [(BP) CAS: 50-32-8] was determined. The study was prompted by a report that a high incidence of tumors occurred in tissues of the upper respiratory and alimentary tracts of Syrian hamsters exposed to BP aerosols. The esophagi of anesthetized hamsters were surgically catheterized so that radiolabeled material instilled as BP in the nose could be collected and analyzed for metabolites. About 50% of the instilled BP was metabolized in the nose and, potentially, would have been swallowed in an awake animal. In auxiliary experiments, homogenates of respiratory and alimentary tissues were tested for metabolic activity for BP. The nose, trachea, and lungs had about equally high activities on a per organ basis (5-7 nmol/hr), whereas all other tissues had considerably less activity. The results of the study indicate that nasal metabolism may be important in causing tumors in alimentary as well as upper respiratory tissues.

Distribution of certain peptide-containing nerve fibres and endocrine cells in the gastrointestinal mucosa in five mammalian species

The distribution of mucosal nerve fibres containing vasoactive intestinal peptide (VIP), substance P, somatostatin, neuropeptide Y (NPY), and enkephalinlike immunoreactivity was mapped by conventional immunohistochemical techniques throughout the mucosa of the esophagus, stomach, small and large intestines, and gall bladder. In addition, the distributions of endocrine cells immunoreactive for three peptides localized by these antisera (namely somatostatin, pancreatic polypeptide, and substance P) were recorded. Tissues from guinea pigs, rats, dogs, marmosets, and humans were studied. It was hoped that this information would enable possible target tissues and functional roles for the peptides to be identified. In the mucosa, peptide nerve fibres were found throughout the lamina propria, including some which were close to the epithelium and others associated with small blood vessels. Although there was a general similarity of peptide nerve distribution between regions and species, many small variations were observed. VIP and substance P fibres were the most prevalent nerve type; NPY fibres were also usually quite common. The distribution of somatostatin fibres was extremely variable between regions and species, and enkephalin fibres were usually rare. Endocrine cells of open (flask- or pyramid-shaped) and closed (rounded) types were seen; basal cytoplasmic processes (of variable length) were seen on many cells immunoreactive for somatostatin or pancreatic polypeptide. Epithelial cells immunoreactive for substance P were seen in the dog, marmoset, and human. The distributions and shapes of endocrine cells varied widely between areas and species. These studies provide a basis for the correlation of nerve distribution with pharmacological and physiological studies.

Heterogeneity of muscarinic receptors in the guinea pig esophageal muscularis mucosae and ileal longitudinal muscle

Pharmacologic characteristics of muscarinic receptors in the muscularis mucosae of the guinea pig esophagus were examined in vitro and compared with those of the longitudinal muscle of the guinea pig ileum. All cholinomimetics tested produced a sustained contraction of the muscularis mucosae, in a concentration-dependent manner, which was associated with a small biphasic change in membrane potential, initially a hyperpolarization followed by a depolarization. The contractile response was hardly modified by verapamil, but was depressed by calcium removal from the bathing medium. Both atropine and pirenzepine antagonized the contractile response in a competitive manner, with higher pA2 values than those in the ileum. These results indicate that the muscarinic receptors of the muscularis mucosae of the guinea pig esophagus mainly link with calcium ion channels which are independent of changes in membrane potential and that their subtype populations are probably pharmacologically distinct from those in the ileal longitudinal muscle.

Distribution of neurotensin in the canine gastrointestinal tract

The distribution of immunoreactive neurotensin in the canine gastrointestinal tract from the esophagus to the rectum, as well as in the pancreas, was determined by a specific neurotensin radioimmunoassay. Immunoreactive neurotensin was found throughout the gastrointestinal tract and in the pancreas. The highest concentrations of immunoreactive neurotensin were found in the mucosal extracts of the jejunum (422 +/- 68 ng/gm) and ileum (3025 +/- 289 ng/gm). Small but substantial amounts of immunoreactive neurotensin were found in the esophagus, fundus (includes fundus and corpus), antrum, duodenum, colon, and pancreas. The concentrations of neurotensin in the mucosal extracts of the jejunum and ileum increased in a graded fashion from the proximal jejunum to the distal ileum. The neurotensin concentration in extracts of the seromuscular layers of jejunum (73 +/- 14 ng/gm) and ileum (187 +/- 38 ng/gm) were statistically higher in comparison with other gut loci.

Keratin expression in normal esophageal epithelium and squamous cell carcinoma of the esophagus

The 8-nm keratin filament is a major component of the cytoskeleton of epithelial cells and epithelial-derived cancers (carcinomas). Recently, it has been shown that the pattern of keratins produced by an esophageal epithelial cell undergoes change upon malignant transformation. In order to evaluate the potential importance of these differences in providing improved diagnostic techniques for pathology, we have investigated the consistency of the patterns of keratins expressed in normal esophageal epithelium, squamous cell carcinoma (SQCC) of the esophagus, and cultured esophageal epithelial cells. In six patients, the keratin pattern expressed by SQCC of the esophagus and corresponding normal esophageal epithelium was consistently different as judged by immunoblot analysis of electrophoretically separated protein extracts. Whereas the SQCCs typically expressed major keratins with molecular weights of 58,000, 56,000, 50,000, and 46,000, the normal esophageal epithelium produced two major keratins with molecular weights of 58,000 and 52,000 and a minor keratin with a molecular weight of 56,000. When normal esophageal epithelial cells were grown in tissue culture, their keratin pattern changed, and keratins with molecular weights of 58,000, 56,000, 52,000, 50,000, 46,000, and 40,000 were expressed. Although some minor variations in keratin patterns were seen, the major differences in keratin pattern expressed by normal esophageal epithelial tissue, SQCC of the esophagus, and cultured esophageal cells were consistent and reproducible.

Distribution and molecular forms of peptides containing somatostatin immunodeterminants in extracts from the entire gastrointestinal tract of man and pig

Specimens from human porcine mucosal and muscular tissue from the entire gastrointestinal tract were extracted in acid ethanol, subjected to chromatography and analysed for somatostatin-like immunoreactivity by region-specific radioimmunoassays. The concentration of somatostatin-like immunoreactivity from man and pig ranged from 1.13 +/- 0.37 to 101.15 +/- 33.93 pmol/g wet weight, and from 7.64 to 159.48 +/- 23.79 pmol/g wet weight, respectively. In both species the highest concentrations were found in the jejunum. The immunoreactivity in intestinal mucosal extracts was distributed among four major peaks, two of which were identified by HPLC as somatostatin 1-28 and somatostatin 1-14, respectively. A peak of approx. 10 kDa was resolved by ion exchange plus HPLC into three components, two containing at least part of the somatostatin 1-14 sequence as well as (part of) the somatostatin 1-28(1-14) sequence (but differing in charge), the third containing only the 1-28(1-14) sequence. These peptides probably represent uncleaved and partially cleaved prosomatostatin. The fourth component to be identified by gel filtration was slightly larger than somatostatin 1-14. Extracts from the antrum, the pancreas and from muscular tissues contained almost exclusively somatostatin 1-14, and very little somatostatin 1-28, indicating that the somatostatin precursor is processed differently at these sites. Furthermore, extracts of porcine gastric antrum, analysed for somatostatin 1-28(1-14) immunoreactivity, showed two immunoreactive forms in the mucosa and three major forms in the muscular layers.