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Biomedical subjects

I M Samloff

Publications and source records attributed to I M Samloff.

At least 37 records · Page 2Linked to original sources
PubMed1991

Alpha 1-antitrypsin allo- and phenotypes in gastric and duodenal ulcer.

Serum alpha 1-antitrypsin (A1AT) allo- and phenotypes (including M1, M2 and M3 alleles) were studied in 99 patients with gastric ulcer (GU) and 56 patients with duodenal ulcer (DU) using agarose isoelectric focusing. The results were compared with the A1AT data of a random population sample of similar genetic background (1422 persons). An increase in M2 allotype and M1M2 phenotype as well as a decrease in Z allotype of A1AT was seen in GU in comparison to DU and the random population. There were no particular clinical features which would distinguish patients with M2 allotype from the remainder of the GU group. However, a trend toward elevated serum pepsinogen I and II levels in patients with M2 allotype was seen. When the pepsinogen levels were compared in the GU patient groups with and without M2 allotype, matched between themselves by the state of the gastric mucosa, a statistically significant difference was revealed between pepsinogen II levels in these two groups. No associations were found between DU and any of the A1AT phenotypes.

Adult↗
PubMed1991

Serum pepsinogen I and serum gastrin in the screening of severe atrophic corpus gastritis.

The possibilities to screen atrophic corpus gastritis with serum pepsinogen I (S-PGI) and serum gastrin (S-gastrin) concentrations have been studied in 774 subjects: 71 index subjects selected from a general population at random, 353 of their first-degree relatives, 276 first-degree relatives of patients with gastric cancer, 53 patients with pernicious anaemia, and 21 of their relatives. Discrimination function analysis was calculated from members of random and gastric carcinoma families. S-PGI less than 30 ng/ml had a high sensitivity for severe diffuse atrophic corpus gastritis (SDAG) alone (89.5%) and SDAG + severe patchy atrophic corpus gastritis (SPAG) (89.1%). Respective figures for specificity were 91.5% and 94.8%. The discriminatory power of S-PGI less than 30 ng/ml and S-PGI less than 25 ng/ml was of the same order. The sensitivity of low S-PGI decreased sharply in detection of slighter forms of atrophic corpus gastritis. The sensitivity of S-gastrin greater than 100 pmol/l to discriminate SDAG was 57.9% and SDAG+SPAG 58.7%. Respective figures for specificity were 90.2% and 92.2%. Diffuse and patchy atrophic changes behaved similarly regarding S-PGI and S-gastrin mean concentrations. Accordingly, the biopsy specimen with the severest atrophic changes indicates the degree of atrophy, which associates closely with the changes in S-PGI and S-gastrin. In conclusion, severe atrophic (diffuse or patchy) corpus gastritis may be screened from a general population with high sensitivity and specificity by low S-PGI less than 30 ng/ml, whereas an increased level of S-gastrin is too insensitive for this.

Aged↗
PubMed1991

Serum pepsinogen I and serum gastrin in the screening of atrophic pangastritis with high risk of gastric cancer.

Serum pepsinogen I (S-PGI) and serum gastrin (S-gastrin) were examined in the screening of three types of atrophic gastritis with inherent high risk of gastric cancer: in 102 cases with severe atrophic corpus gastritis (SACG), in 5 cases with severe atrophic antrum gastritis (SAAG), and in 15 cases with severe atrophic pangastritis (SAPG) (atrophy both in corpus and in antrum) found among 916 subjects from three family series (265 from gastric cancer families, 425 from randomly selected control families and 226 from pernicious anaemia families). There is no way to screen directly atrophic gastritis restricted to the antral mucosa. In pangastritis atrophy of antral glands causes a failure of the hypergastrinemic reaction of achlorhydria. The combination of S-PGI less than 25 micrograms/l + S-gastrin less than 200 pmol/l detected 80.0% of our cases with SAPG, and only 17 subjects of 794 (2.1%) were false positives i.e. who had not advanced atrophic gastritis. The risk of gastric cancer may be significantly higher in SAPG than in SACG. The estimated prevalence of SAPG was 3% in random-family members over 60 years. The combination of S-PGI and S-gastrin is recommended when the cost/benefit ratio in the screening program of gastric cancer is considered and people from a general population are selected for endoscopic studies.

Anemia, Pernicious↗
PubMed1990

Ductal cancers of the pancreas frequently express markers of gastrointestinal epithelial cells.

It has been found by immunohistochemical staining that antigens normally found in gastric and/or intestinal epithelial cells are expressed in most differentiated duct cell carcinomas of the pancreas. Among 88 such tumors, 93% and 92%, respectively, expressed M1 and cathepsin E, markers of gastric surface-foveolar epithelial cells, 51% expressed pepsinogen II, a marker of gastroduodenal mucopeptic cells, 48% expressed CAR-5, a marker of colorectal epithelial cells, and 35% expressed M3SI, a marker of small intestinal goblet cells. Most of the tumors also expressed normal pancreatic duct antigens; 97% expressed DU-PAN-2, and 59% expressed N-terminus gastrin-releasing peptide. In agreement with these findings, electron microscopy revealed malignant cells with fine structural features of gastric foveolar cells, gastric mucopeptic cells, intestinal goblet cells, intestinal columnar cells, pancreatic duct epithelial cells, and cells with features of more than one cell type. Normal pancreatic duct epithelium did not express any marker of gastrointestinal epithelial cells, whereas such benign lesions as mucinous cell hypertrophy and papillary hyperplasia commonly expressed gut-type antigens but rarely expressed pancreatic duct cell markers. By contrast, lesions characterized by atypical papillary hyperplasia commonly expressed both gastric and pancreatic duct cell markers. Metaplastic pyloric-type glands expressed pepsinogen II and, except for their expression of cathepsin E, were indistinguishable from normal pyloric glands. In marked contrast, the immunohistochemical and ultrastructural features of 14 ductuloacinar cell tumors were those of cells lining terminal ductules, centroacinar cells, and/or acinar cells; none expressed any gut-type antigen. The results indicate that gastrointestinal differentiation is common in both benign and malignant lesions of pancreatic duct epithelium and suggest that duct cell carcinomas are histogenetically related to gastric- and intestinal-type metaplastic changes of epithelial cells lining the main and interlobular ducts of the pancreas.

Antibodies, Monoclonal↗
PubMed1990

The foveolar cell component of gastric cancer.

M1, a mucin antigen, and cathepsin E, an aspartic proteinase, are both expressed in normal gastric superficial-foveolar epithelial cells. In this study, we determined by immunohistochemical staining the prevalence of these antigens in 316 gastric cancers representative of the main histologic types and stages of the disease. M1 was expressed in 201 cases (64%) and cathepsin E was expressed in 235 cases (75%) of the 313 cases investigated. Both antigens were expressed more commonly in diffuse and mixed cancers than in glandular tumors. M1 was found in 64 of 83 (77%) diffuse cancers and in 48 of 59 (81%) mixed cancers, but in only 74 of 146 (51%) glandular cancers. For cathepsin E, the prevalence was 93% in diffuse cancer, 81% in mixed cancer, and 71% in the 143 glandular cancers examined. Among 25 mucoid tumors, 15 (60%) expressed M1 but only eight (32%) expressed cathepsin E. Overall, 262 (84%) of the tumors expressed at least one of these antigens and of these, 173 (66%) expressed both antigens. No significant difference in the prevalence of M1 or cathepsin E was found between early and advanced cancer or between metastatic and nonmetastatic cancer. The two markers differed in their intracellular localization. In superficial-foveolar cells, M1 immunostaining was concentrated in secretory granules, Golgi complex, and luminal mucous, whereas cathepsin E was found in the endoplasmic reticulum. Moreover, cathepsin E, but not M1, was found in the enterocytes of duodenal villi and, occasionally, in mucopeptic cells. Parallel histochemical and ultrastructural investigations confirmed the occurrence in gastric cancer of foveolar-type cells, manifested by periodic acid-Schiff- and/or alcian blue-reactive mucous granules having a punctate substructure. We conclude that superficial-foveolar cell differentiation is common in gastric cancer and is a major component of this type of tumor. However, pure foveolar cell differentiation is rare. Rather, most gastric cancers consist of cells exhibiting features of foveolar, intestinal, and mucopeptic cell lines.

Antibodies↗
PubMed1989

Stabilisation of cathepsin E by ATP.

The hydrolysis of 3 distinct substrates by cathepsin E from human red blood cells and gastric mucosa was measured in the presence and absence of physiologically relevant concentrations of ATP. At pH values below about 5.0, the nucleotide was without effect. However, at pH 5.8, whereas cathepsin E was virtually inactive by itself, it was restored to full activity (kcat) by ATP and the non-hydrolysable methylene-ATP analogue. At still higher pH values, kcat progressively diminished but significant levels of cathepsin E activity were readily detectable at pH 7.0. The specificity of this stabilisation effect was examined.

Adenosine Triphosphate↗
PubMed1989

Human pepsinogen C (progastricsin) polymorphism: evidence for a single locus located at 6p21.1-pter.

A series of six clones containing the entire human pepsinogen C gene (PGC) was identified in a cosmid vector library by using cDNA and oligonucleotide probes. The 10.7-kb PGC gene includes nine exons and exhibits a high degree of sequence identity (60%) with the functionally related pepsinogen A genes. The predicted amino acid sequence was identical with the partial amino-terminal and carboxyl-terminal sequences of purified pepsinogen C. An informative restriction fragment length polymorphism was detected with several restriction enzymes and involved an insertion or deletion of 100 bp of intron sequence located between exons 7 and 8. Evidence that there is only a single PGC gene in humans is presented. The PGC gene and the prolactin gene were regionally localized to 6p21.1-pter by analysis of mouse X human somatic cell hybrids.

Amino Acid Sequence↗
PubMed1989

Peptic ulcer: the many proteinases of aggression.

Peptic activity has long been recognized as an essential factor in the pathogenesis of peptic ulcer and related diseases, but only recently has it become clear that this activity is derived from a remarkable diversity of enzymes, all of which belong to the aspartic proteinase family of enzymes. These include two types of pepsinogens and two types of cathepsins. In recent years, considerable progress has been made in characterizing these proteinases and in applying this information to the study of a number of gastrointestinal disorders. The intent of this article is to update recent basic and clinical information on these topics and to suggest several areas that merit further investigation.

Animals↗
PubMed1988

Identification of the aspartic proteinases from human erythrocyte membranes and gastric mucosa (slow-moving proteinase) as catalytically equivalent to cathepsin E.

Three aspartic proteinases with similar Mr values (approx. 80,000) but from distinct sources (human gastric mucosa, human erythrocyte membranes and rat spleen) were shown to have immunological cross-reactivity and comparable mobilities when subjected to polyacrylamide-gel electrophoresis under non-denaturing conditions. Kinetic parameters (kcat, Km and Ki) were determined for the interactions of the three enzymes with two synthetic chromogenic substrates and five inhibitors (naturally occurring and synthetic). On this basis it would appear that all of the enzymes should be considered equivalent to cathepsin E. pH-activity measurements indicated that the aspartic proteinase that originated from the erythrocyte membranes retained activity at a higher pH value than either of its readily soluble counterparts.

Animals↗
PubMed1988

Expression of pepsinogen II in gastric cancer. Its relationship to local invasion and lymph node metastases.

We have determined the prevalence of pepsinogen II (PG II) immunoreactive cells in a large series of early and advanced gastric cancers and relationships among PG II-positivity, tumor histologic type, extent of gastric wall invasion, and presence of lymph node metastases. Of the 316 cancers evaluated, 150 (47%) expressed PG II. The prevalence by histologic type was 55% in 146 glandular tumors, 43% in 83 diffuse tumors, 16% in 25 mucoid tumors, and 51% in 59 mixed-type cancers. Two parietal cell cancers and one undifferentiated cancer were PG II-negative. In glandular and diffuse cancers, but not mucoid and mixed tumors, both the extent of gastric wall invasion and incidence of lymph node metastases were associated positively with PG II expression by the primary tumor. In particular, PG II-reactive cells were found significantly more often in advanced than in early diffuse cancers (P less than 0.05) and significantly more often in submucosal early cancers than in intramucosal early cancers (P less than 0.01). The prevalence of PG II expression also was higher significantly in metastatic cancers than in nonmetastatic cancers. This was true for advanced gastric cancers as a whole (P less than 0.01), advanced glandular-type cancer alone (P less than 0.01), advanced glandular- and diffuse- type cancers together (P less than 0.001), and early diffuse-type cancer (P less than 0.05). Only four (3%) of 145 cancers evaluated for pepsinogen I (PG I) were positive, and each also was positive for PG II. The results suggest that the expression of PG II by glandular and diffuse types of gastric cancer may be a marker of increased malignancy.

Humans↗
PubMed1988

Serum pepsinogen I in familial multiple endocrine neoplasia type I.

An increased serum pepsinogen I (PG I) concentration has been reported to be a marker of inherited peptic ulcer disease. Since both the Zollinger-Ellison syndrome and hyperparathyroidism, components of the familial multiple endocrine neoplasia type I syndrome (MEN I), are often associated with peptic ulcer, we have studied serum PG I concentrations in members of six well-defined families with MEN I. Serum PG I concentrations in 20 family members with hyperparathyroidism ranged from 35 to 864 ng/ml compared to 21-92 ng/ml in 16 nonaffected MEN I members. However, serum PG I levels were significantly higher (P less than 0.01) in the hyperparathyroid patients with hypergastrinemia (PGI median 192, range 75-864 ng/ml) than in those with normogastrinemia (PGI median 75, range 35-139 ng/ml). In fact, five of seven patients with hyperparathyroidism and hypergastrinemia compared to only one of 13 hyperparathyroid patients without hypergastrinemia had increased serum PG I levels above 130 ng/ml. We conclude that in the MEN I syndrome, increased serum PG I levels are found in patients with Zollinger-Ellison syndrome but not in hyperparathyroid patients with normogastrinemia and not in nonaffected MEN I members. The results indicate that in familial MEN I, hyperpepsinogenemia I is not inherited as a genetic trait but suggest that the elevated serum PG I levels are secondary to chronic hypergastrinemia.

Female↗
PubMed1988

Slow moving proteinase in gastric cancer and its relationship to pepsinogens I and II. An immunohistochemical study.

Slow-moving proteinase (SMP), pepsinogen I (PG I), and pepsinogen II (PG II) are aspartic proteinases normally found in gastric mucosa. Because of differences in their cellular origins, normal gastric epithelial cells can be phenotyped by immunohistochemical staining with a panel of antisera to each proteinase. In this study, we determined aspartic proteinase phenotypes of malignant cells in 74 cases of gastric cancer by immunohistochemical staining with rabbit antiserum to human SMP, PG I, and PG II. Of the 74 cancers, 20 were histologically of the diffuse type and 54 were of the intestinal (or mixed) type. Intestinal metaplasia was characterized by the presence of SMP (but not PG I or PG II) in absorptive epithelial cells. SMP was found in 40 (54%) of the cancers (vs 31% for PG II and only 5% for PG I) and in both the intestinal and diffuse types. Of the 40 SMP-positive cancers, 14 also expressed PG II. In the latter tumors, staining of adjacent sections revealed that some malignant cells expressed only SMP or only PG II, whereas others expressed both proteinases. Overall, 49 (66%) of the cancers contained cells with proteinase phenotypes characteristic of cells in nonmalignant gastric mucosa and 23% contained cells with proteinase phenotypes characteristic of more than one cell type. The results indicate that both intestinal- and diffuse-type gastric cancers often differentiate to cell types that produce aspartic proteinases and that about one fourth contain a heterogeneous population of malignant cells.

Cathepsins↗
PubMed1988

Effect of proximal gastric vagotomy on serum pepsinogen I and II concentrations and acid secretion in duodenal ulcer patients.

Acid secretion and basal serum pepsinogen I and II concentrations were measured in 14 duodenal ulcer patients before and at intervals up to six years after proximal gastric vagotomy. Vagotomy led to significant and long-standing reductions in basal, vagally mediated (induced by sham feeding), and peak pentagastrin-stimulated acid secretion. Serum pepsinogen I concentrations also decreased significantly after vagotomy but to a significantly lesser extent than acid secretion. There was no correlation between serum pepsinogen I concentrations and peak acid secretion, either before or after vagotomy. Serum pepsinogen II concentrations decreased only slightly and transiently after vagotomy. Thus, proximal gastric vagotomy reduces acid hypersecretion and pepsinogen I hypersecretion, but not pepsinogen II hypersecretion, in duodenal ulcer patients.

Duodenal Ulcer↗
PubMed1988

Life events stress and psychosocial factors in men with peptic ulcer disease. II. Relationships with serum pepsinogen concentrations and behavioral risk factors.

We examined in a controlled study whether psychologic disturbances in men with peptic ulcer disease were related to other potential ulcer "risk factors" (serum pepsinogen concentrations, cigarette smoking, and intake of alcohol, aspirin, or coffee). Psychopathology in general, personality features of hostility, irritability, and hypersensitivity, and impaired coping ability (low ego strength) each correlated significantly with serum pepsinogen concentration in ulcer patients (p less than or equal to 0.005). Cigarette smoking and intake of alcohol and aspirin were increased in ulcer patients but unrelated to psychopathology. Depression was the variable that best discriminated ulcer patients from nonulcer controls; a negative perception of life events, number of relatives with ulcer, and serum pepsinogen I concentration also had a major, unique discriminating value, whereas smoking played a relatively minor role independent of the other variables examined. Our study supports the concept that several interacting factors (psychologic, behavioral, and genetic/physiologic) are likely involved in peptic ulcer disease. Emotional stress may predispose to ulcers by producing gastric hypersecretion, as manifested by hyperpepsinogenemia.

Acetaminophen↗
PubMed1988

Aspartic proteinases in gastric mucosa of the rat: absence of pepsinogen I, genetic polymorphism of pepsinogen II, and presence of slow-moving proteinase.

We have examined relationships among the aspartic proteinases in rat and human gastric mucosa by electrophoretic analysis in polyacrylamide gel and by immunoblotting and immunohistochemical staining using rabbit antisera to human pepsinogen I (PG I), pepsinogen II (PG II), and slow-moving proteinase. By electrophoretic analysis, the major proteolytic bands in mucosal extracts from each of three strains of rats had rates of anodal migration that were similar to the fastest migrating isozymogens of human PG I. However, immunoblots revealed that these bands and several minor proteolytic bands with slower rates of anodal migration reacted with antiserum to PG II. Two proteolytic bands in rat gastric mucosa that migrated concurrently with human slow-moving proteinase reacted with antihuman slow-moving proteinase reacted with antihuman slow-moving proteinase. None of the proteolytic bands in rat gastric mucosa reacted with anti-PG I. By immunohistochemical staining, anti-PG I failed to stain any cells in rat fundic gland or antral mucosa. By contrast, anti-PG II stained mucus neck and chief cells in fundic gland mucosa and pyloric gland cells in antral mucosa, and anti-slow-moving proteinase stained surface and foveolar epithelial cells throughout the stomach. The results indicate that the gastric mucosa of the rat does not contain PG I.

Animals↗
PubMed1988

Comparison of gastric acid secretion rates and serum pepsinogen I and II concentrations in Occidental and Oriental duodenal ulcer patients.

The purpose of these controlled studies was to determine the prevalence of acid-pepsinogen hypersecretion in 173 patients with duodenal ulcer disease [88 Americans (75 men, 13 women) and 85 Chinese (66 men, 19 women)]. One-half to two-thirds of duodenal ulcer patients of either sex had acid hypersecretion or hyperpepsinogenemia, or both. When Chinese and American duodenal ulcer patients were compared, the two ethnic groups had similar serum pepsinogen I and II concentrations and similar maximal acid outputs per kilogram body weight. In contrast, Chinese duodenal ulcer patients had significantly lower basal acid outputs per kilogram body weight than American duodenal ulcer patients. We conclude that acid-pepsinogen hypersecretion is present in the majority of American and oriental duodenal ulcer patients.

Adult↗