PTEN mutations do not cause nuclear beta-catenin accumulation in endometrial carcinomas

PTEN: and beta-catenin mutations constitute the predominant genetic alterations in endometrioid carcinomas of the endometrium. PTEN encodes a dual-specificity phosphatase with lipid phosphatase and protein tyrosine phosphatase activities that regulate both apoptosis and interactions with the extracellular matrix. Recent studies have associated PTEN mutations with tumorigenesis of prostate carcinoma via the Wnt signaling pathway, leading to nuclear beta-catenin accumulation. To elucidate the potential interaction of PTEN and beta-catenin in endometrial cancer, we performed mutation analyses of the entire PTEN gene and of exon 3 of the beta-catenin gene that is most frequently targeted by mutations. A total of 82 endometrial carcinomas comprising 62 type I endometrioid carcinomas and 20 type II high-grade carcinomas were investigated. In addition in a subset of 22 carcinomas, the intracellular beta-catenin distribution was analyzed by immunohistochemistry. Overall, 20 (24.4%) of 82 tumors revealed mutations in the PTEN gene, and 16 (19.5%) of 82, in the beta-catenin gene. Six tumors (7.3%) showed mutations in both the PTEN and beta-catenin gene. Mutations were mainly detected in endometrioid carcinomas of the endometrium. As expected, a striking nuclear accumulation of beta-catenin could be shown in tumors with beta-catenin mutations. In the vast majority of tumors with PTEN mutations, a regular staining pattern of the cytoplasmic and membranous compartments was found. We therefore conclude that, in contrast to prostate cancer, mutations in the PTEN gene seem not to affect cellular distribution of the beta-catenin protein in endometrial carcinomas.

High telomerase activity is associated with cell cycle deregulation and rapid progression in endometrioid adenocarcinoma of the uterus

Telomerase activity, a mechanism granting cellular immortality, has been detected in most cancer entities, but its association with clinical, histopathologic, and prognostic parameters is not fully understood. We investigated whether quantitative telomerase levels are correlated to established prognostic factors, telomere lengths, cell cycle kinetics, and the clinical course in endometrioid adenocarcinoma of the uterus (EC). A modified telomeric repeat amplification protocol (TRAP) was used to quantify the relative telomerase activity in a series of 53 primary tumors. Mean telomere length was determined by Southern blot analysis. Cell cycle kinetics were studied immunohistochemically on paraffin sections using monoclonal antibodies to 2 distinct proliferation-specific proteins: Ki-67, which is expressed throughout the cell cycle, and a novel cell cycle-associated protein, repp86, the expression of which is restricted to the cell cycle phases S, G2, and M. The ratio of the 2 immunolabeling indices defines the rate of transition through the restriction point. Telomerase activity was detected in 50 of 53 ECs (94%). Its levels correlated significantly with FIGO stage (P =.01) and FIGO grade (P =.003) but not with myometrial invasion. They were weakly associated with the overall proliferative activity (Ki-67, r =.48) but significantly with the repp86 index (r =.64) and even more strongly with the repp86:Ki-67 ratio (r =.77). There was no correlation with mean telomere length. In the group of tumors with high telomerase activity, 5 patients had relapses and 2 died of the disease within a median follow-up period of 29 months. Recurrence showed no relation to FIGO grade and stage. No events were observed in the group with low telomerase activity. In a multivariate model including tumor stage, histopathologic grade, depth of myometrial invasion, and Ki-67 indices, telomerase activity emerged as the only independent predictor of disease progression (P =.0002). It is concluded that beyond a link to proliferation, high telomerase activity reflects a deregulation of the cell cycle associated with an increased rate of cells entering S phase and a higher degree of malignancy. Therefore, quantitative analysis of telomerase activity may be useful for identifying EC patients at high risk for recurrence.

Telomerase, immortality and cancer

Replication of eukaryotic linear chromosomes is incomplete and leaves terminal gaps. The evolutionary widely distributed solution to this "end replication" is twofold: chromosome ends are capped with telomeres, bearing multiple copies of redundant telomeric sequences, and the telomerase enzyme can add (lost) telomeric repeats. Telomerase in humans, as in all mammals, is ubiquitous in all embryonic tissues. In adults, telomerase remains active in germs cells, and, although down-regulated in most somatic tissues, telomerase is active in regenerative tissues and notably, in tumor cells. Telomerase activity is linked to cellular proliferation, and its activation seems to be a mandatory step in carcinogenesis. In contrast to mammals, indeterminately growing multicellular organisms, like fish and crustaceae, maintain unlimited growth potential or 'immortality' in all somatic tissues throughout their entire life. Also this cell immortalization is brought about by maintaining telomerase expression. Disease prognosis for human tumors includes evaluation of cell proliferation, based on the detection of proliferation markers with monoclonal antibodies. The significance of the classical marker Ki-67, and of a novel marker repp-86 are compared with semiquantitative telomerase assays. For tumor therapy, telomerase inhibitors are attractive tools. Results with telomerase knock-out mice have revealed promise, but also risk of this approach. On the other side, telomerase stimulation is attractive for expanding the potential of cellular proliferation in vitro, with possible applications for transplantation of in vitro expanded human cells, for immortalizing primary human cells as improved tissue models, and for the isolation of otherwise intractable products, like genuine human monoclonal antibodies.

Prognostic significance of a novel proliferation marker, anti-repp 86, for endometrial carcinoma: a multivariate study

Traditional prognostic factors often fail to identify a subgroup of endometrial carcinoma (EC) patients with an apparently paradoxical poor outcome. We therefore analyzed tumor cell proliferation immunohistochemically in a series of 164 endometrial carcinomas (EC) and compared its prognostic impact with that of the standard prognostic factors patient age, FIGO stage, FIGO grading, and histopathologic subtype. In addition to the established proliferation markers Ki-S5 (Ki-67) and KiS4 (topoisomerase IIalpha), we used a novel monoclonal antibody (MAb), anti-repp 86, which binds to a recently described proliferation-specific protein (p86) expressed exclusively in the S, G2, and M phases of the cell cycle. anti-repp 86, Ki-S4, and Ki-S5 immunoreactive labeling indices (LI) correlated significantly with FIGO stage, FIGO grade, and myometrial invasion, but not with histopathologic subtype. By univariate analysis, conventional prognostic factors and proliferation indices were all predictive of disease-related mortality. A multivariate Cox regression analysis selected anti-repp 86 LI (P = .002), FIGO stage (P = .02), and histopathologic type as significant prognosticators of recurrence; anti-repp 86 LI (P = .001) and histopathologic type (P = .0106) also emerged as relevant predictors of mortality. A hierarchical forward regression model with the conventional prognosticators entered first and with anti-repp 86 entered next showed that anti-repp 86 and histopathologic subtype were the superior independent prognostic indicators for an increased risk of recurrence and cancer-related death. We conclude that the evaluation of anti-repp 86 immunostaining is an easily performable and exceptionally reliable method for identifying EC patients with adverse prognosis.

Immunohistochemical assessment of p170 provides prognostic information in endometrial carcinoma

AIMS

To determine the significance of proliferative activity (PA) in endometrial carcinomas, we analysed the expression of cell cycle-related antigens in routinely processed tissue.

METHODS AND RESULTS

Serial sections of 164 endometrial carcinoma specimens were immunostained with the monoclonal antibodies (MoAb) Ki-S4 (specificity for p170) and Ki-S5 (specificity for p320/350). The Ki-S4 PA (median value 18.3%) and Ki-S5 PA (median value 25.0%) in endometrial carcinomas showed a significant correlation (r = 0.89, P < 0.001). A significantly lower median value of Ki-S4 and Ki-S5 immunoreactivity was ascertained in endometrial carcinomas stage I vs. > I (P < 0.05), in tumours with myometrial invasion < or = 50% vs. > 50% (P < 0.03), and in grade 1 vs. grade 2 and 3 tumours (P < 0.001). Univariate analysis showed that age, FIGO stage and grade, histopathological subtype, myometrial invasion, Ki-S4 and Ki-S5 PA provided prognostic information on the adjusted overall survival, whereas FIGO stage (P = 0.002) and Ki-S4 PA (P = 0.008) were independent prognosticators for adjusted overall survival in multivariate analysis.

CONCLUSIONS

The association with established prognosticators for endometrial carcinomas, and the results of uni- and multivariate analysis indicates that the additional evaluation of Ki-S4 PA is useful for classifying patients into subgroups with low and high risk of relapse which might help individualizing the therapeutic strategy in endometrial cancer patients.

Correlation between p53, c-erbB-2, and topoisomerase II alpha expression, DNA ploidy, hormonal receptor status and proliferation in 356 node-negative breast carcinomas: prognostic implications

Various new prognostic indicators have been identified for mammary carcinomas, but the issue of their significance remains unsettled. The prognostic impact of p53, c-erbB-2, and topoisomerase II alpha expression was investigated in relation to standard prognostic factors for carcinomas of the breast and to the tumour cell growth fraction. Paraffin-embedded specimens of 356 node-negative infiltrating ductal carcinomas were stained immunohistochemically using a polyclonal antiserum to c-erbB-2, and the monoclonal antibodies DO-1 (p53), Ki-S4 (topoisomerase II alpha), and Ki-S5 (Ki-67). The patients were followed for a median duration of 99 months. Both p53 and c-erbB-2 were significantly associated with high tumour grade, large tumour size, DNA aneuploidy, lack of steroid hormone receptors, young age, and increased topoisomerase II alpha and Ki-67 expression levels. The correlation of p53 and c-erbB-2 was not significant. Topoisomerase II alpha and Ki-67 scores closely paralleled each other, indicating that both reflect the proliferative activity of tumour cells. A univariate analysis of overall (OS), specific (SS), and disease-free survival (DFS) revealed all the above-mentioned parameters to be statistically significant except patient age, which was relevant only to overall survival. Multivariate analysis with inclusion of all covariates selected tumour size and proliferation (topoisomerase II alpha and Ki-67) indices as independent predictors of survival in all three models. No additional information was gained by p53 or c-erbB-2. It is concluded that the proliferative activity, as assessed by topoisomerase II alpha or Ki-67 immunostaining, is the most useful indicator of breast cancer prognosis, except for tumour size.

Analysis of telomerase expression and proliferative activity in the different layers of cyclic endometrium

To gain better insights into cell kinetics under physiological conditions, telomerase activity in the functional and basal layers of cyclic endometrium (n = 33) was compared with the immunostaining of glandular and stromal cells within these layers (n = 25). Two immunohistochemical proliferation markers were used to demarcate cells in the G1 phase of the cell cycle. In contrast to previous expectations, telomerase activity and both glandular and stromal proliferative activities were all significantly higher in the functional than in the basal endometrium (P < 0.002). The course of telomerase activity in the endometrial layers during the ovarian cycle was significantly associated with the proliferative scores for the functional and basal endometrial glands and the functional stroma but not the stromal compartment of the basal layer. Our findings indicate that the telomerase activity in cyclic endometrium is associated with the total number of proliferating glandular and stromal cells in the functional layer. Proliferating daughter cells of telomerase-competent stem cells may account for the lower levels of telomerase detected in normal basal endometrium.

Telomere shortening in uterine leiomyomas

OBJECTIVE

To gain a better understanding of proliferation control mechanisms in a common benign tumor, we investigated the mean telomere length and the clonality of uterine leiomyomas.

STUDY DESIGN

Deoxyribonucleic acid from uterine leiomyomas and from the adjacent normal myometrium of 51 patients (total number of uterine leiomyomas 107; 28 patients with single leiomyoma, 23 patients with multiple leiomyomas ranging from 2 to 8 myoma nodules per case) was hybridized to a telomeric oligonucleotide probe by Southern blot and chemiluminescent detection. The mean telomere length was evaluated by densitometry. Clonality was assessed with use of the phosphoglycerokinase gene polymorphism.

RESULTS

The mean telomere length was significantly shorter in uterine leiomyomas (median 7950 bp, interquartile range 7261 to 8372 bp) than in normal myometrium (median 9688 bp, interquartile range 8528 to 10535 bp) (P < .001). There was no correlation between tumor size and telomere attrition. Multiple uterine leiomyomas were found to have an independent clonal origin.

CONCLUSIONS

Telomere attrition in uterine leiomyomas reflects enhanced proliferation activity in the course of tumor evolution. The basic telomere lengths differ in the myocytes from which the uterine leiomyomas originate, probably explaining the lack of correlation between telomere attrition and tumor size.

[Intact pregnancy with concomitant hydatidiform mole of a coexisting placenta]

The simultaneous occurrence of an intact pregnancy with normal placenta morphology and sonographic signs of a hydatidiform mole of a second placenta, which was diagnosed in the 14th gestational week, is described. Prenatal diagnostic and perinatologic management will be reported. The difference of the placentas will be shown by histopathology.

Fetal heart rate (FHR) pathology in labor related to preceeding Doppler sonographic results of the umbilical artery and fetal aorta in appropriate and small for gestational age babies. A longitudinal analysis

The aim of this study was to ascertain the value of serially performed Doppler sonographic measurements of fetal vessels for the prediction of FHR alterations in labor a longitudinal analysis was conducted. 24 patients with SGA fetuses as the only risk factor and 38 patients without any risk factor were recruited for the study. Flow velocity waveforms of the fetal aorta and the umbilical artery were analyzed for systolic diastolic (S/D) ratio weekly at 20-39 weeks gestation and from 30 weeks gestation onwards twice weekly. Courses were related to complications during labor reflected by alterations of FHR tracings. The more numerous pathologie S/D ratios of both fetal vessels were recorded the more frequently complications in labor occurred (Chi Square test, p < 0.05). The mean value of the S/D ratios in fetuses with FHR pathology in labor differed significantly compared to the uncomplicated group (Wilcoxon rank sum test, p < 0.05). The fluctuation of S/D ratios was greater in the complicated than in the normal group (Wilcoxon rank sum test, p < 0.05). A combination of parameters describing S/D ratios showed a sensitivity of 86% and a specificity of 19% for the fetal aorta and a sensitivity of 71% and a specificity of 91% for the umbilical artery. Serial Doppler measurements of the fetal aorta and the umbilical artery aid in predicting pathologic FHR alterations in labor and may be of benefit in antenatal care to ensure fetal well being particularly in cases of IUGR.

A higher rate of hyperandrogenic disorders in female-to-male transsexuals

In an effort to elucidate the aetiology of female-to-male transsexualism (FM-TS) 12 out of an annual sample of 16 untreated female-to-male transsexuals (FMT), aged 19 years 7 months (19;7) to 44 years 8 months (44;8) [median age (M) 27;5] were assessed by means of sexual-medical questionnaires, physical and endocrinological examination. The control group consisted of 15 healthy women (CF), aged 19 years 2 months (19;2) to 36 years 1 month (36;1) (M 22;7) without gender identity disorder, who were not under hormonal medication (including contraceptives). Baseline levels of testosterone (T; ng/dl), androstenedione (A4; ng/dl), dehydroepiandrosterone sulfate (DHEAS; ng/ml), luteinizing hormone (LH; IU/l), follicle stimulating hormone (FSH; IU/l), and sex-hormone binding globuline (SHBG; microgram/dl) were measured. A standard single-dose ACTH stimulation test (250 micrograms ACTH IV; Synacthen) was performed with all subjects. Aldosterone (ALDO), corticosterone (B), deoxycorticosterone (DOC), progesterone (PROG), 17-hydroxyprogesterone (17OHP), 11-deoxycortisol (S), cortisol (F), cortisone (E), pregnenolone (PREG) and 17-hydroxypregnenolone (OHPREG) were assessed before and 60 min after ACTH stimulation. Transvaginal ultrasound was performed in nine out of 12 FMT (20;11 to 44;8, M 27;5; m 29.1 +/- 7.5) but not in CF. Results showed that 10 FMT (83.3%) and five CF (33.3%) were above normal values for at least one of the measured androgens. Baseline levels of T and A4 were significantly higher in FMT than in CF (T: 54.0 +/- 13.8 vs. 41.1 +/- 12.8; A4: 244.8 +/- 73.0 vs. 190.5 +/- 49.3; p < .05), whereas DHEAS, SHBG, LH and FSH did not differ between the groups. Unbound T (T/SHBG ratio) was higher in FMT (72.0 +/- 67.6) than in CF (26.4 +/- 15.1). Baseline levels of 17OHP, OHPREG and DOC were higher in FMT than in CF (p < .05). After ACTH stimulation 17OHP and OHPREG remained higher in FMT than in CF (p < .05). Single case analysis of ACTH stimulation test together with physical examination revealed symptoms for non-classical congenital adrenal hyperplasia (NC-CAH) in six FMT (50%) and two CF (13.3%). Eight out of nine FMT who were assessed by means of transvaginal ultrasound (i.e. 88.9%; 50.0% of 16) had polycystic ovaries (PCO). Oligomenorrhoea or menstrual dysregularities (81.7% of 16 FMT vs. 0% of CF), hirsutism (56.2% of 16 FMT vs. 13.3% of 15 CF) and adiposity (25.0% vs. 0%) were frequent in FMT, but not in CF. Hyperandrogenism with polycystic ovarian syndrome (PCOS) and adrenocortical hyperresponsiveness to ACTH seems to be a common finding in FMT. This offers support for a hormonal factor in the genesis of FM-TS. Because the prevalence of PCOS and NC-CAH in the female population is higher than FM-TS, the true nature of this factor and its interaction with environmental influences remains unknown.

[Follow-up of beta-hCG after pelviscopic linear salpingotomy for therapy of tubal pregnancy]

From 1987 until 1993 a total of 337 patients underwent a therapy for tubal pregnancy at the Department of Gynaecology and Obstetrics of the University of Kiel. The percentage of cases treated by tubal-preserving pelviscopic linear salpingotomy and subsequent extraction of the conceptus, increased from 59% in 1987 to 88% in 1993. In 6.5% a second look pelviscopy was performed for suspected remnants of trophoblastic tissue. Remaining trophoblastic cells can be recognised by serial determination of serum beta-hCG titers postoperatively. However, the interval of the postoperative beta-hCG decline reveals considerable interindividual variation. A regression following the "Cox Proportional Hazard" model shows that the period of the beta-hCG decline depends on the initial titer. The Kaplan Meier curve obtained via beta-hCG determination in 98 patients following pelviscopic linear salpingotomy until values reached 20 mIU/ml or less, shows that 50% of the patients had to be controlled for more than 7 days, 10% for more than 28 days and individual patients even for more than 70 days. The relative beta-hCG titers differ significantly from the unresolved group compared to the group with resolved ectopic pregnancy starting at postoperative day 2 (p < 0.01). At postoperative day 3/4 10% of the initial beta-hCG value is attained in 50% of cases. Even then a serial beta-hCG follow-up should be obtained down to the detection limit to ensure complete resolution of viable trophoblastic cells.

[Lung metastasis after pelviscopic salpingectomy in therapy of tubal pregnancy]

A 34-year old VI gravida, II para underwent a pelviscopic salpingectomy of the left fallopian tube for treatment of a repeated ectopic pregnancy. Histology revealed an invasive hydatidiform mole. The declining beta-hCG titers after surgery were not further controlled. Seven months later a secondary amenorrhoea occurred again; beta-hCG levels increased steadily. We could not obtain trophoblastic tissue by operative pelvis-copy (excision of the tubal stump on the left side and tubal sterilisation on the right side) nor by curettage of the uterine cave. A lesion of the lung was interpreted as a metastatic lesion following malignant transformation of the invasive hydatidiform mole and disappeared under cytotoxic therapy containing methotrexate with an uneventful follow-up period of now 4 years.

RECOMMENDATION

In order not to overlook the presence of persistent trophoblastic tissue and the possible development of a choriocarcinoma, beta-hCG serum titers should be measured until they disappear, following the surgical therapy of an ectopic pregnancy.

Management of patients with persistent beta-hCG values following laparoscopic surgical and local drug treatment for ectopic pregnancy

OBJECTIVES

To show that the beta-human chorionic gonadotropin (hCG) decline following tubal-preserving techniques for ectopic pregnancy (EP) can take a longer course than currently believed, indicating expectant management; and to define the indications for a second-look laparoscopy if beta-hCG persists.

METHODS

Three hundred thirty-seven patients treated for EP were retrospectively reviewed. In order to define the 'normal' beta-hCG decline following tubal-preserving techniques we acquired a Kaplan-Meier curve for 98 patients treated by laparoscopic linear salpingotomy, the main method performed for EP (253 patients). The Mann-Whitney U-test served as a statistical test. The patient population requiring a second-look laparoscopy for proliferating trophoblastic remnants is described.

RESULTS

Twenty-eight patients (8.3%) required a second-look laparoscopy (acute abdominal pain and sonographically suspect findings combined with increasing beta-hCG values). The majority (15 patients) underwent a preceding laparoscopic linear salpingotomy (6.5% unresolved cases). The relative beta-hCG values differed significantly from the unresolved group compared to the group with resolved EP starting at postoperative day 2 (P < 0.01). A maximal beta-hCG decline period of 77 days postoperatively was observed.

CONCLUSIONS

Patients with slowly declining beta-hCG levels following tubal-preserving techniques for EP can be managed expectantly. Increasing beta-hCG values combined with abdominal pain and sonographically suspect observations indicate a second-look laparoscopy.

Macrophage- and lymphocyte-subtypes in the endometrium during different phases of the ovarian cycle

The presence of immunocompetetive cells in the endometrium during the proliferative and secretory phase of the ovarian cycle is demonstrated on the light and electron microscopic level using monoclonal antibodies (MoAb). Subtypes of monocytes, macrophages and T-lymphocytes appear during the different phases in variable extent and different localization. Some subpopulations of the monocyte/macrophage system and T-helper lymphocytes increase in number on day 21/22. Our observations indicate that cells with bone marrow origin take part in functional events of the endometrium during the ovarian cycle.

[Immunophenotyping of lymphoreticular cells in the human decidua]

The endometrial stroma is transformed into decidua by an adequate hormonal stimulus or by pregnancy, the endometrial stroma is transformed into decidua. There is increasing evidence, that the decidua has a central functional relevance for the survival of the mammalian embryo in an immunological competent host. In this study, the decidua of 10 patients were examined after therapeutic abortion in the 8th-10th week of pregnancy. Various monoclonal antibodies were used for immunophenotyping of lymphoreticular cells. Most intradecidual lymphoreticular cells could be identified as Ki-M6+ and Ki-M8+ macrophages, which also expressed HLA-DR (class-II) antigens. This finding is underlined by the fact, that Tü-35+ cells occurred in comparable numbers as macrophages and B-lymphocytes were virtually absent from the decidua. Next in frequency were OKT3-positive T-lymphocytes. Most of the lymphoid cells were detected by monoclonal antibody OKT8 (suppressor/cytotoxic lymphocytes) while OKT4+ helper/inducer cells occurred only in low numbers. Though definite conclusions in the cells' functional properties cannot be drawn from an immunohistological study, our findings might be regarded as a basis to explain the tolerance of the embryo in this apparently privileged immunological site.

Methodological dependence in the ultrastructural immunolocalization of laminin in tubular basement membranes of the mouse kidney

The ultrastructural localization of the basement membrane glycoprotein laminin was investigated in basement membranes of proximal tubules of the mouse kidney. The localization of laminin was determined using two different immunoperoxidase and one immunogold preembedding technique and one immunogold postembedding technique on unfixed and formaldehyde fixed tissue. Strong differences in the immunolocalization for laminin were found in the lamina densa of the tubular basement membrane using different techniques. After preembedding immunostaining for laminin using IgG--PO as secondary antibody, a positive reaction for the lamina densa was found in the formaldehyde fixed as well as in the unfixed kidney. After preembedding immunostaining for laminin using Protein-A--PO, staining of the 1. densa was seen in the unfixed, but not in the fixed kidney. It was striking that no clear immunoreaction in the 1. densa of the tubular basement membrane was seen in either the fixed or unfixed tissue after preembedding immunostaining for laminin using protein A-gold. With a direct postembedding immunogold technique laminin was localized only in the 1. fibroreticularis and the 1. rara but not in the 1. densa of basement membranes of proximal tubules of the unfixed and the fixed kidney.

Effect of short- and long-term feeding of omeprazole on rat gastric endocrine cells

Rats were tube-fed with omeprazole (40 mumol/kg body weight twice daily) for 30 and 60 days. As a result, fasting plasma gastrin levels were significantly elevated, while plasma somatostatin levels remained normal. Gastrin concentrations in the antral mucosa were unchanged after 30 days, but significantly elevated after 60 days. The relative stomach weight and the area of the antral and oxyntic mucosa increased significantly; however, the oxyntic mucosa thickness and the volume density of the parietal cells did not increase. Highly significant changes occurred in the endocrine cells of the antrum and corpus. The volume density of the argyrophilic (Grimelius technique) cells of the oxyntic mucosa increased time-dependently, and so did the volume density of the antral G cells, while the volume density of the antral D cells decreased. This resulted in a remarkable increase in the G/D cell ratio. All functional and morphological changes are reversed 42 days after omeprazole feeding for 60 days. The findings in the endocrine cells of the antral mucosa are explained by the omeprazole-induced permanent elevation of the intragastric pH and in the endocrine cells of the oxyntic mucosa by the following hypergastrinaemia.