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Biomedical subjects

A W Eriksson

Publications and source records attributed to A W Eriksson.

At least 73 records · Page 4Linked to original sources

Clinical significance of pepsinogen A isozymogens, serum pepsinogen A and C levels, and serum gastrin levels.

Gastric mucosal pepsinogen A phenotype, serum pepsinogen A level, serum pepsinogen C level, serum pepsinogen A/pepsinogen C ratio, and serum gastrin level were evaluated as potential markers for gastric cancer or its precursors in 19 healthy volunteers and 341 patients from the gastroscopy program. Gastric cancer, atrophic gastritis, and intestinal metaplasia of the stomach were associated with pepsinogen A phenotypes, characterized by an intense fraction 5, and with a low serum pepsinogen A level (less than 25 micrograms/l), a low serum pepsinogen A/pepsinogen C ratio (less than 1.5), and a high serum gastrin level (greater than 79 ng/l). The specificity of pepsinogen A phenotypes with an intense fraction 5 for gastric cancer or its precursors was 95.1% with a sensitivity of 20.4%. The sensitivity and specificity of the noninvasive tests were evaluated with the receiver operating characteristic. For clinical purposes, a serum pepsinogen A/pepsinogen C ratio less than 1.8 is the most suitable test, with a sensitivity of 74% and a specificity of 76% for gastric cancer or its precursors, with a reference population of patients with benign gastric disorders. However, the sensitivity and specificity of the single or combined tests are too low for population screening purposes.

Adult↗

Molecular cloning of a pair of human pepsinogen A genes which differ by a Glu----Lys mutation in the activation peptide.

Three human cosmid clones containing pepsinogen A (PGA) encoding sequences were isolated from a genomic bank derived from a single individual. One cosmid contains two PGA genes in tandem in a head-to-tail orientation, while the other two cosmids each contain a single PGA gene. The three cosmids were characterized by restriction mapping and sequence analysis (exons 1 and 2 and flanking regions). As judged from these data, three of the four PGA genes isolated appear to be nearly identical, but one of the tandem genes is clearly different from the other genes. The first exon of all four genes codes for the same amino acid sequence. However, in the second exon of one of the tandem genes we found a nucleotide substitution giving rise to a Glu----Lys substitution of the 43rd amino acid residue of the activation peptide, leading to a charge difference of the corresponding isozymogens. The presence of two distinct PGA genes in the isolated gene pair conclusively proves the multigene structure of the PGA system. These genes might be responsible for at least part of the electrophoretic polymorphism at the protein level.

Amino Acid Sequence↗

Gastric proteases in Barrett's esophagus.

Precursors of the gastric proteases pepsinogen A (pepsinogen I) and pepsinogen C (pepsinogen II) and slow-moving protease were demonstrated in biopsy specimens from Barrett's epithelium in 21 of 22 patients with Barrett's esophagus; in 14 of them, in variable combinations at different sites. In 13 of 19 patients (68.4%) with detectable pepsinogen A, different isozymogen patterns were found between the Barrett's epithelium and the gastric corpus mucosa. Discrepancies consisted mainly of a stronger pepsinogen 5 band in the Barrett's epithelium, with a higher incidence in biopsy specimens with features of dysplasia than with no or indefinite dysplasia; the difference was, however, not statistically significant. Zymograms of 69 biopsy specimens from Barrett's epithelium were correlated with the histologic type: pepsinogen A and C were most frequently found in the fundic type, least often in the specialized intestinal type. In control gastric corpus biopsy specimens, pepsinogen A and C as well as slow-moving protease were always detectable. The observed variability of gastric protease patterns, in particular of pepsinogen A isozymograms, may be due to differences in expression within the pepsinogen A cluster, suggesting a deregulation of gene expression or partial deletion of the pepsinogen A gene cluster.

Adult↗

Statistical models for the twinning rate.

Linear regression models are used to explain the variations in the twinning rates. Data sets from different countries are analysed and maternal age, parity and marital status are the main regressors. The model building technique is also used in order to study the secular decline in the twinning rate. Linear regression technique makes it possible to compare the effect of different factors but the method requires sufficiently disaggregated data.

Australia↗

Increasing trend in the monozygotic twinning rate.

Recent changes in the estimated incidence of monozygotic twinning in 15 European populations are described. The overall trend was an increase in the monozygotic twinning rate (MZTR) since the 1960s, particularly in those countries in which the use of oral contraceptives (OC) was widespread. A slower increase or even a decrease in the MZTR was observed in countries with low use of OC. Some countries, eg, Sweden, demonstrated an unexpectedly sharp increase since the 1960s. In Poland and the Federal Republic of Germany the MZTR was already strongly increasing as early as in the 1950s, clearly before the introduction of the pill. The influence of several other factors on the MZTR is discussed, such as toxic and teratogenic agents, pelvic infection diseases caused by the use of intrauterine devices, the increased use of ovulation inducers and neuroleptics as well as changes in the registration of perinatal deaths.

Age Factors↗

Twin studies on urinary pepsinogen A phenotypes and serum pepsinogen A levels.

Urinary pepsinogen A (PGA or PG I) phenotypes and serum PGA levels were studied in MZ and DZ twins and their parents. In 45 out of 48 MZ twin pairs PGA patterns were completely identical, while 3 MZ twin pairs showed minor differences in the relative intensity of the Pg5 isozymogen. This suggests that the intensity of this isozymogen may be influenced by nongenetic factors. There was little difference in the interclass correlations of serum PGA levels between MZ and DZ twins, indicating a large contribution of common environmental factors to serum PGA levels. This is in contrast with previous studies.

Adolescent↗

Enzyme-linked immunosorbent assay and radioimmunoassay of serum pepsinogen A.

The determination of serum pepsinogen A (= pepsinogen I) levels is of clinical importance in the study of duodenal ulcer, atrophic gastritis and gastric cancer. In the present study two different quantitative immunological techniques for serum pepsinogen A were compared: a radioimmunoassay (RIA) (Helsinki) and an enzyme-linked immunosorbent assay (ELISA) (Amsterdam). Serum samples of 177 subjects with various gastric diseases were tested in a double blind study. The correlation was excellent (r = 0.954 in the range 0-760 micrograms/l and r = 0.971 in the range 0-100 micrograms/l). The functional relationship between ELISA (x) and RIA (y), determined by weighted model II regression, was y = 1.12x-0.54. Initially the use of goat anti-PGA in the ELISA resulted in falsely high values in about 10% of the individuals. This was caused by circulating antibodies cross-reacting with goat IgG. This artefact was eliminated by pre-incubation of all samples with non-immune goat serum.

Clinical Trials as Topic↗

Pepsinogen A polymorphism in gastric mucosa and urine, with special reference to patients with gastric cancer.

Electrophoretic pepsinogen A patterns were determined in gastric fundic mucosa biopsies from 601 patients with various gastric disorders and 25 healthy volunteers. Pepsinogen A patterns with an intense fraction 5 appeared to be associated with gastric cancer and premalignant changes of the stomach (p less than 10(-9)). In 60 individuals pepsinogen A patterns were determined in normal mucosa from different parts of the stomach. No differences were found between these patterns. In 29 out of 59 gastric cancer patients pepsinogen A could be demonstrated in the macroscopically malignant tissue. In two cases a different pattern compared with uninvolved fundic mucosa was observed. During a follow up study, major changes in the pepsinogen A pattern were observed in 7 out of 56 patients. In 8.6% of the examined patients urinary pepsinogen A patterns differed considerably as compared with the pattern observed in the gastric fundus. The results suggest that the highly significant association between intense Pg5 (the product of the D gene) and gastric cancer or its precursors may be caused by genetic as well as non-genetic factors.

Gastric Fundus↗

The Cowden syndrome: a clinical and genetic study in 21 patients.

An analysis of the findings in 21 patients with the Cowden syndrome or the multiple hamartoma syndrome is presented. The Cowden syndrome is a cancer-associated genodermatosis with characteristic mucocutaneous findings and a wide array of associated abnormalities including a high incidence of breast cancer in female patients. Genetic studies confirmed autosomal dominant inheritance with a high penetrance in both sexes and moderate interfamilial and intrafamilial differences in the expressivity of a number of symptoms. Familial occurrence was present in 4 of the 7 families. There was a strong predominance of female patients (6:1), which may be fortuitous. Mucocutaneous changes were the most constant (100% incidence) and characteristic findings; they almost invariably became manifest in the second decade. Four of our 18 female patients (22%) were treated for breast cancer, a lower incidence than reported previously. No increased incidence of other types of malignancies was found. Craniomegaly (high head circumference) was found to be the most common extracutaneous manifestation (80% incidence); craniomegaly appears to be an important early marker. We also found high incidences of gastrointestinal polyps (approximately 60%) and cutaneous fibromas (76%), while the incidence of thyroid abnormalities, thus far regarded as the most common extracutaneous finding, was similar to that reported previously (62%). G-banded karyotype and preliminary DNA-repair studies revealed no clear abnormalities. No linkage with the loci of HLA, and immunoglobulin haplotypes was found.

Abnormalities, Multiple↗

Alpha 1-antitrypsin in acute anterior uveitis and rheumatic diseases.

To test the pathogenetic role of the phenotype MZ of alpha 1-antitrypsin/alpha 1-protease inhibitor (PI) in acute anterior uveitis (AAU) and in different rheumatic diseases we examined 360 unrelated patients including 93 with AAU alone, 24 patients with AAU and ankylosing spondylitis (AS), 21 patients with AAU and Reiter's disease (RD), 26 patients with AAU, AS, and RD 54 patients with AS alone, 16 patients with RD alone, 115 patients with rheumatoid arthritis (RA) alone, and 11 patients with psoriatic arthritis (PA) alone. Of the 164 AAU patients, 80 had a single attack, and 84 had repeated episodes. There were neither significant differences between different groups of the patients and 120 healthy controls nor between patients with AAU alone and patients with AAU and AS or RD in the frequencies of the PI phenotypes tested. The results indicate that the PI MZ type is not closely associated with AAU, AS, RD, RA and PA and that it does not play any role in determining whether AAU shows a pattern of a single attack or repeated episodes, and whether AAU occurs alone or together with AS or RD.

Acute Disease↗

The influence of omeprazole on the synthesis and secretion of pepsinogen in isolated rabbit gastric glands.

Regulation mechanisms of pepsinogen (EC 3.4.23.) synthesis and secretion were studied by following newly synthesized [14C]-labeled pepsinogen during culture of isolated rabbit gastric glands. Omeprazole, a substituted benzimidazole, while almost completely abolishing acid production at 10(-4) M, strongly stimulated secretion of preformed and newly synthesized pepsinogen. Although the pepsinogen synthesis at this concentration of omeprazole was reduced to about 55% of the control rate, a two-fold absolute increase of total secreted pepsinogen was found. This increase was not due to a non specific leakage through disruption of chief cell membranes, as no increase of lactate dehydrogenase in the culture medium could be demonstrated. The stimulated secretion was influenced neither by 10(-3) M cimetidine, 10(-3) sodium thiocyanate nor 10(-4) M atropine. No additivity was found between the carbachol (10(-4) M) or dibutyryl cyclic AMP (10(-3) M) and the omeprazole induced pepsinogen secretion.

Animals↗

Assignment of human pepsinogen A locus to the q12-pter region of chromosome 11.

A 0.9kb cDNA fragment, corresponding to a large part of Rhesus monkey pepsinogen A mRNA, was used as probe for the chromosomal localization of the human pepsinogen A gene(s) using human-rodent somatic cell hybrids. Southern blot analysis of 14 human-Chinese hamster and three human-mouse cell hybrids, strongly indicates that the human PGA locus is on chromosome 11. The human-mouse hybrids, containing a translocation involving chromosome 11, allow sublocalization to the region q12-pter.

Animals↗

Pepsinogen synthesis in monolayer culture of human and rabbit gastric mucosal cells.

We have established monolayer cultures of human and rabbit gastric mucosal cells and of isolated rabbit gastric chief cells. These cultures were capable of de novo pepsinogen synthesis and secretion, demonstrated by electrophoresis and subsequent autoradiography of cell lysates and growth medium after culture in the presence of 14C-labelled amino acids. Cultures could be maintained for 1 week without overgrowth by fibroblasts.

Animals↗

Aland eye disease: no albino misrouting.

Electrophysiological studies showed that a patient with Aland eye disease had no misrouting of the optic pathways which is always found in all forms of albinism as a consequence of the retino-geniculate anomaly. Also the spontaneous and optokinetic nystagmus did not resemble that of the large majority of human albinos. The marked asymmetry found in this patient seems to be typical for humans with a defective development of foveal binocular vision. These findings are in agreement with clinical, nystagmographic and EM findings that Aland eye disease is distinct from the Nettleship-Falls type of X-linked ocular albinism. Furthermore, Aland eye disease is different from X-chromosomal congenital stationary night blindness with myopia by the fact that the scotopic functions are only moderately affected and there is no restriction of the peripheral photopic visual fields. In addition, there is latent nystagmus of extraocular type that appears also in female carriers. There is no ophthalmoplegia, there is a progression of the myopia and the dyschromatopsia is of secondary type.

Adult↗

Purification of the pepsinogen A isozymogens by means of high resolution ion-exchange chromatography. Evidence for post-translational modifications.

Total human pepsinogen (PG) was isolated from gastric fundic mucosa and PGA (formerly called PGI) from urine, using standard ion-exchange and gel filtration techniques. Gastric PGA was separated from PGC (formerly called PGII) either by immunoaffinity or high resolution ion-exchange chromatography (fast protein liquid chromatography, Pharmacia, Uppsala, Sweden). The individual PGA isozymogens 2, 3, 4 and 5 could be isolated to homogeneity with the aid of the same ion-exchanger. Evidence was obtained for the existence of secondary modifications of the PGA fractions 3, 4 and 5, electrophoretically overlapping the primary (genetic) isozymogens.

Chromatography, Gel↗

Pepsinogen synthesis and secretion by isolated gastric glands.

De novo synthesis of pepsinogens was demonstrated in gastric glands isolated from rabbit and human gastric mucosa. The isolated glands were incubated in an amino acid free, Minimum Eagles Medium supplemented with a 14C labelled amino acid mixture. The glands were centrifuged at different time intervals and aliquots of gland homogenates and medium were run on polyacrylamide slab gels. Newly synthesized pepsinogens were demonstrated by autoradiography. Incorporation of 14C was detected after 30 minutes of culture and increased almost linearily with time over 4 h. By comparing the electrophoretic patterns after autoradiography, protein and pepsinogen activity staining, it was concluded that the glands synthesize mainly pepsinogens. Cimetidine, at a concentration of 10(-4)M strongly inhibited pepsinogen synthesis. Spontaneous secretion of pepsinogens into the medium was very low and relatively constant. Cyclic dibutyryl AMP markedly stimulated the secretion of pepsinogens into the medium. The results show, that isolated gastric glands are capable of synthesis and secretion of pepsinogens and that each function can be stimulated and inhibited selectively.

Animals↗