Visceral obesity and muscle mass determined by CT scan and surgical outcome in patients with advanced ovarian cancer. A retrospective cohort study

OBJECTIVE

Visceral obesity (VO) is a risk factor for developing postoperative complications in patients undergoing abdominal oncological surgery. However, in ovarian cancer patients this influence of body composition on postoperative morbidity is not well established. The aim of this study is to assess the association between body composition and complications in patients with advanced ovarian cancer undergoing cytoreductive surgery.

METHODS

Patients with FIGO stage 3 or 4 ovarian cancer between 2006 and 2017 were included. Visceral fat area, total skeletal mass and total fat area were measured on a single slice on the level of L3-L4 of the preoperative CT-scan. VO was defined as visceral fat ≥100cm². The perioperative data were extracted retrospectively. A multivariate logistic regression analysis was performed to test the predictive value of multiple variables such as body composition, albumin levels and preoperative morbidity.

RESULTS

298 consecutive patients out of nine referring hospitals were included. VO patients were more likely to be hypertensive (38% vs 17% p < 0.001), and to have an ASA 3 score (21% vs 10% P = 0.012). Complications occurred more often in VO patients (43% vs 21% P < 0.001). Thrombotic events were found in 4.9% of VO patients versus 0.6% of the non-visceral obese patients (p = 0.019). VO(OR: 4.37, p < 0.001), hypertension (OR:1.9, p = 0.046) and duration of surgery (OR: 1.004, p = 0.017) were predictors of post-surgical complications. Muscle mass is not a predictor of complications.

CONCLUSION

Visceral obesity is associated with a higher occurrence of complications in patients with advanced ovarian cancer undergoing cytoreductive surgery.

Multipotent Adult Progenitor Cells, but Not Tissue Inhibitor of Matrix Metalloproteinase-3, Increase Tissue Sparing and Reduce Urological Complications following Spinal Cord Injury

Following spinal cord injury (SCI), inflammation amplifies damage beyond the initial insult, providing an opportunity for targeted treatments. An ideal protective therapy would reduce both edema within the lesion area and the activation/infiltration of detrimental immune cells. Previous investigations demonstrated the efficacy of intravenous injection of multipotent adult progenitor cells (MAPC^®) to modulate immune response following SCI, leading to significant improvements in tissue sparing, locomotor and urological functions. Separate studies have demonstrated that tissue inhibitor of matrix metalloproteinase-3 (TIMP3) reduces blood-brain barrier permeability following traumatic brain injury in a mouse model, leading to improved functional recovery. This study examined whether TIMP3, delivered alone or in concert with MAPC cells, improves functional recovery from a contusion SCI in a rat model. The results suggest that intravenous delivery of MAPC cell therapy 1 day following acute SCI significantly improves tissue sparing and impacts functional recovery. TIMP3 treatment provided no significant benefit, and further, when co-administered with MAPC cells, it abrogated the therapeutic effects of MAPC cell therapy. Importantly, this study demonstrated for the first time that acute treatment of SCI with MAPC cells can significantly reduce the incidence of urinary tract infection (UTI) and the use of antibiotics for UTI treatment.

Quality of life from a randomized trial of open and endovascular repair for abdominal aortic aneurysm

Background

Long-term survival is similar after open or endovascular repair of abdominal aortic aneurysm. Few data exist on the effect of either procedure on long-term health-related quality of life (HRQoL) and health status.

Methods

Patients enrolled in a multicentre randomized clinical trial (DREAM trial; 2000–2003) in Europe of open repair versus endovascular repair (EVAR) of abdominal aortic aneurysm were asked to complete questionnaires on health status and HRQoL. HRQoL scores were assessed at baseline and at 13 time points thereafter, using generic tools, the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36®) and EuroQol 5D (EQ-5D™). Physical (PCS) and mental component summary scores were also calculated. Follow-up was 5 years.

Results

Some 332 of 351 patients enrolled in the trial returned questionnaires. More than 70 per cent of questionnaires were returned at each time point. Both surgical interventions had a short-term negative effect on HRQoL and health status. This was less severe in the EVAR group than in the open repair group. In the longer term the physical domains of SF-36® favoured open repair: mean difference in PCS score between open repair and EVAR −1·98 (95 per cent c.i. −3·56 to −0·41). EQ-5D™ descriptive and EQ-5D™ visual analogue scale scores for open repair were also superior to those for EVAR after the initial 6-week interval: mean difference −0·06 (−0·10 to −0·02) and −4·09 (−6·91 to −1·27) respectively.

Conclusion

In this study EVAR appeared to be associated with less severe disruption to HRQoL and health status in the short term. However, during longer-term follow-up to 5 years, patients receiving open repair appeared to have improved quality of life and health status.

Rapid assay of stem cell functionality and potency using electric cell-substrate impedance sensing

Regenerative medicine studies using autologous bone marrow mononuclear cells (BM-MNCs) have shown improved clinical outcomes that correlate to in vitro BM-MNC invasive capacity. The current Boyden-chamber assay for testing invasive capacity is labor-intensive, provides only a single time point, and takes 36 hours to collect data and results, which is not practical from a clinical cell delivery perspective. To develop a rapid, sensitive and reproducible invasion assay, we employed Electric Cell-substrate Impedance Sensing (ECIS) technology. Chemokine-directed BM-MNC cell invasion across a Matrigel-coated Transwell filter was measurable within minutes using the ECIS system we developed. This ECIS-Transwell chamber system provides a rapid and sensitive test of stem and progenitor cell invasive capacity for evaluation of stem cell functionality to provide timely clinical data for selection of patients likely to realize clinical benefit in regenerative medicine treatments. This device could also supply robust unambiguous, reproducible and cost effective data as a potency assay for cell product release and regulatory strategies.

Development and internal validation of a prognostic model for survival after debulking surgery for epithelial ovarian cancer

OBJECTIVE

Predicting survival of patients with epithelial ovarian cancer (EOC) is based on prognosis of the population. Combining prognostic factors could facilitate survival prediction on the level of the individual patient. The aim of this study was to develop a prognostic model to predict five-year disease specific survival in patients with EOC, and to evaluate whether this would add to prediction based on prognosis of the population.

PATIENTS AND METHODS

A retrospective cohort study was performed of all EOC patients treated with primary debulking and adjuvant chemotherapy or neo-adjuvant chemotherapy and interval debulking surgery in three gynaecological-oncologic centres between 1998 and 2010. Primary outcome was 5-year disease-specific survival. We developed a Cox proportional hazard model using the LASSO-method to select the best combination of characteristics from 12 potential predictors and to correct for overfitting. Performance of the model was expressed as calibration and discrimination (c-statistic). A nomogram was developed to increase the clinical applicability of the model.

RESULTS

Of 840 patients with EOC 462 (55%) died within 5 years due to the disease. A combination of FIGO stage, residual tumour after surgery, primary or interval surgery, histology, performance status, age, amount of ascites and a family history suggestive of breast/ovarian cancer best predicted 5-year survival. The final model showed accurate calibration and the c-statistic was 0.71 (95% CI 0.69-0.74).

CONCLUSIONS

Five-year survival in all stage EOC patients can be predicted accurately using available characteristics. After external validation the model can be used for counselling of patients.

Fetal cerebellar volume and symmetry on 3-d ultrasound: volume measurement with multiplanar and vocal techniques

The purpose of this prospective longitudinal study was to evaluate the growth of the fetal cerebellar volume by means of 3-D ultrasound to evaluate whether there is a difference between the volumes of the left and right cerebellar hemispheres, and to evaluate the intra- and interobserver reliability of two different techniques of volume measurement. Three-dimensional ultrasound examinations were performed every two to three weeks on 27 fetuses between 20 and 40 weeks' gestation. Measurements of the total cerebellar volume and of the left and right cerebellar hemispheres were done using the multiplanar technique. Multilevel analysis was used to determine the growth of cerebellar volume based on individual developmental trajectories and compare the volume of the right and left hemispheres of the cerebellum. The intra- and interobserver reliability was calculated for the multiplanar and VOCAL techniques in a subgroup of 10 fetuses. A nonlinear growth curve of cerebellar volume in normal pregnancy was generated. The cerebellar growth per two-week decreased from a gain of 51% of the first measurement at 20 weeks to a gain of 16% of the first measurement at 38 weeks. The left cerebellar hemisphere was significantly larger (12.3%, p < 0.01) than the right. The intraclass correlation coefficient for the measurements by the two techniques was 0.99. Intraobserver reliability: the intraclass correlation coefficient for the measurements using the multiplanar technique was 0.96 and 0.97 and for VOCAL it was 0.98 and 0.97 for the two observers, respectively. Interobserver reliability: the intraclass correlation coefficient for the measurements using the multiplanar technique was 0.97 and for VOCAL 0.98. Longitudinal growth curves based on individual developmental trajectories were generated for the cerebellar volume. The left fetal cerebellar hemisphere was found to be significantly larger than the right. Both multiplanar and VOCAL techniques had a good intra- and interobserver reliability and yielded very similar results.

Effects of Helicobacter pylori on intracellular Ca2+ signaling in normal human gastric mucous epithelial cells

In stomach, Helicobacter pylori (Hp) adheres to gastric mucous epithelial cells (GMEC) and initiates several different signal transduction events. Alteration of intracellular Ca2+ concentration ([Ca2+]i) is an important signaling mechanism in numerous bacteria-host model systems. Changes in [Ca2+]i induced by Hp in normal human GMEC have not yet been described; therefore, we examined effects of Hp on [Ca2+]i in normal human GMEC and a nontransformed GMEC line (HFE-145). Cultured cells were grown on glass slides, porous filters, or 96-well plates and loaded with fura 2 or fluo 4. Hp wild-type strain 60190 and vacA-, cagA-, and picB-/cagE- isogenic mutants were incubated with cells. Changes in [Ca2+]i were recorded with a fluorimeter or fluorescence plate reader. Wild-type Hp produced dose-dependent biphasic transient [Ca2+]i peak and plateau changes in both cell lines. Hp vacA- isogenic mutant produced changes in [Ca2+]i similar to those produced by wild type. Compared with wild type, cagA- and picB-/cagE- isogenic mutants produced lower peak changes and did not generate a plateau change. Preloading cultures with intracellular Ca2+ chelator BAPTA blocked all Hp-induced [Ca2+]i changes. Thapsigargin pretreatment of cultures to release Ca2+ from internal stores reduced peak change. Extracellular Ca2+ removal reduced plateau response. Hp-induced peak response was sensitive to G proteins and PLC inhibitors. Hp-induced plateau change was sensitive to G protein inhibitors, src kinases, and PLA2. These findings are the first to show that H. pylori alters [Ca2+]i in normal GMEC through a Ca2+ release/influx mechanism that depends on expression of cagA and picB/cagE genes.

Helicobacter pylori induces apoptosis in Barrett's-derived esophageal adenocarcinoma cells

Helicobacter pylori may protect against the development of dysplasia in Barrett's epithelium of patients with gastroesophageal reflux disease. The aim of this study was to determine whether H. pylori preferentially induces apoptosis in Barrett's-derived cancer cells compared to normal cells. A Barrett's-derived adenocarcinoma cell line (OE33) was grown. H. pylori wild-type, isogenic vacA-, cagA(-), and picB-/cagE- mutant strains were grown on agar plates. Intact or sonicated bacteria were used to treat normal and OE33 cells for 24 hours, and Hoechst dye binding was performed to measure apoptosis. FAS protein expression was determined by Western immunoblotting. OE33 cells treated with intact H. pylori wild-type strains produced significant (P < 0.05) dose-dependent increases in apoptosis compared to normal esophageal cells. H. pylori wild-type and vacA- isogenic strains were more effective than cagA- and picB-/cage- isogenic strains in inducing apoptosis in OE33 cells. In OE33 cells, H. pylori sonicates produced lower levels of apoptosis than intact bacteria. Wild-type H. pylori strains increased Fas protein expression in OE33 cells at 18 hours. H. pylori induced apoptosis at a higher rate in the Barrett's-derived human esophageal adenocarcinoma cells than in normal esophageal cells. The H. pylori-induced apoptosis was primarily dependent on intact bacteria and the presence of the cagA and picB/cagE gene products. H. pylori-induced apoptosis may involve the Fas-caspase cascade.

Identification of a functional Ca2+-sensing receptor in normal human gastric mucous epithelial cells

The purpose of the present study was to determine whether human gastric mucous epithelial cells express a functional Ca2+-sensing receptor (CaR). Human gastric mucous epithelial cells were isolated from surgical tissues and cultured on glass coverslips, plastic dishes, or porous membrane filters. Cell growth was assessed by the MTT assay, CaR localization was detected by immunohistochemistry and confocal microscopy, CaR protein expression was assessed by Western immunoblotting, and intracellular Ca2+ concentration ([Ca2+]i) was determined by fura 2 spectrofluorometry. In paraffin sections of whole stomach, we found strong CaR immunohistochemical staining at the basolateral membrane, with weak CaR-staining at the apical membrane in mucous epithelial cells. Confocal microscopy of human gastric mucous epithelial cell cultures showed abundant CaR immunofluorescence at the basolateral membrane and little to no CaR immunoreactivity at the apical membrane. Western immunoblot detection of CaR protein in cell culture lysates showed two significant immunoreactive bands of 140 and 120 kDa. Addition of extracellular Ca2+ to preconfluent cultures of human gastric mucous epithelial cells produced a significant proliferative response. Changes in [Ca2+]i were also observed in response to graded doses of extracellular Ca2+ and Gd3+. The phospholipase C inhibitor U-73122 specifically inhibited Gd3+-induced changes in [Ca2+]i in the gastric mucous epithelial cell cultures. In conclusion, we have identified the localization of a functional CaR in human gastric mucous epithelial cells.

Prolonged survival of adult rat pancreatic islets transfected with E1A-12S adenovirus

It has been reported that various mutants of the E1A-adenovirus can activate quiescent differentiated cells to start proliferating. The aim of this study was to determine whether transfection with E1A-12S could extend the life span and functionality of pancreatic islets in culture. Rat pancreatic islets were isolated and transfected with retrovirus containing the adenovirus E1A-12S, E1A-13S, or control vectors. Transfection with the retroviral E1A-13S mutant produced extensive islet necrosis compared with nontransfected islets. Islets transfected with the control E1A mutant Ad5-dl312 vector (containing no E1A-12S or E1A-13S segments) were similar to nontransfected islets in their characteristics. We found that the E1A-12S transfected islets maintained greater viability, insulin granule structure, and glucose-induced insulin responsiveness over a 6-week period compared with mock or control islets. At 6 weeks of culture, the E1A-12S transfected islets also had fewer apoptotic cells compared with nontransfected islets. These data suggest that adenovirus E1A-12S can extend the functional life span of cultured rat pancreatic islets.

Effects of paclitaxel on the growth of normal, polyposis, and cancerous human colonic epithelial cells

BACKGROUND

The specific paclitaxel dose or time course in the treatment of colon carcinoma without the disruption of normal colonic cell proliferation is currently not known. The aim of this study was to determine the effects of paclitaxel on the growth of human colonic epithelial cells using cultures of normal, polyposis, and cancerous cells.

METHODS

Normal, polyposis, and cancerous human colonic cells (Caco-2, T-84, and LoVo cell lines) were cultured, then treated with paclitaxel (10(-9)-10(-5) M) for 0-7 days.[AU: Please verify all dosages throughout.] Cell proliferation was assayed using either a Coulter-Counter or MTT-growth assay. Immunofluorescence and Western immunoblotting measured P-glycoprotein.

RESULTS

Low paclitaxel doses (1 x 10(-9)-10(-8) M) were more effective than higher paclitaxel doses (>1 x 10(-8) M) in the growth inhibition of polyposis, Caco-2, and LoVo cancer (but not T-84) cell lines. Low paclitaxel doses had little effect on normal colonic cell growth over 7 days. Higher paclitaxel doses (>1 x 10(-8)-10(-5) M) produced a dose-dependent inhibitory effect on the growth of normal human colonic epithelial cells over 7 days but had no effect on the growth of polyposis, Caco-2, and LoVo cells over 3-7 days of treatment. Immunofluorescence and Western immunoblotting of cultures showed that 1 x 10(-6) M paclitaxel increased P-glycoprotein expression in Caco-2 and LoVo cells. There was no effect of paclitaxel on P-glycoprotein expression in T-84 cancer cells, which were found to have high endogenous basal levels of P-glycoprotein. P-glycoprotein expression in Caco-2 cells was found on plasma membranes and in perinuclear areas.

CONCLUSIONS

Lower paclitaxel doses are more effective over time for the growth inhibition of polyposis and cancerous colonic cells, with minimal effects on the growth of normal colonic epithelial cells. Increased P-glycoprotein expression appears to be correlated with paclitaxel resistance in polyposis and cancerous colonic cells.

Meniscal cysts: detection with high-resolution sonography

OBJECTIVE

The purpose of this study was to determine the feasibility of high-resolution sonography for the detection of meniscal cysts and associated meniscal tears and for the differentiation of meniscal cysts from other masses at the knee joint.

SUBJECTS AND METHODS

Fifty consecutive patients (51 knees) with a palpable mass at the knee joint were examined prospectively using a 7.5-MHz annular array transducer. Mass consistency and location and meniscal integrity were evaluated. Sonographic findings were correlated with surgery (46/51) and histopathology (15/51). Five patients did not undergo surgery.

RESULTS

At surgery, 32 masses appeared to be meniscal cysts, whereas 19 were other types of masses. Sonographically, 31 of the 32 meniscal cysts were diagnosed correctly. Sonographic differentiation of the other types of masses from meniscal cysts could reliably be made in 17 of 19 cases; two masses were falsely interpreted as meniscal cysts. Sensitivity, specificity, and accuracy of sonography in the depiction of meniscal cysts were 97%, 86%, and 94%, respectively. The positive predictive value was 94% and the negative predictive value was 92%. Meniscal tears (31/46) and meniscal tears concomitant with meniscal cysts (26/32) were detected with an accuracy of 83% and 88%, respectively.

CONCLUSION

Sonography is an accurate imaging technique for the detection of meniscal cysts and associated meniscal tears. Differentiation of meniscal cysts from other cystic and solid masses at the knee joint can be reliably made with sonography.

Masses and pain in the groin: a review of imaging findings

The inguinofemoral region is a crossroads of numerous vascular, nervous and muscular structures. As even the most astute clinician can have difficulty in correctly diagnosing the cause of complaints or a mass in the groin and thigh region, radiological investigation is frequently warranted. For the radiologist involved, knowledge of the anatomy and specific pathology of the groin is essential. This paper deals with the imaging characteristics of the various diseases in the inguinofemoral triangle. Furthermore, this article provides an overview of the role of the various imaging modalities in the evaluation of disease in the groin and upper thigh. A sound working knowledge of groin anatomy and pathology is mandatory. The various imaging modalities used should be considered complementary.

Nontuberculous mycobacterial bursitis and arthritis of the shoulder

A 56-year-old woman with systemic lupus erythematosus developed septic arthritis and bursitis of the left shoulder due to an atypical mycobacterium, M. xenopi. Plain radiography, ultrasound (US), and MRI were performed. Articular disease by tuberculous and nontuberculous mycobacteria have similar presentations, clinically as well as radiologically, and have to be differentiated from other chronic bacterial or fungal infections, pigmented villonodular synovitis, rheumatoid arthritis, gout, hemophilia, and synovial chondromatosis. Although atypical mycobacterial involvement of the skeleton and soft tissues is relatively uncommon, its incidence is increasing, as is the incidence of extrapulmonary tuberculosis in western countries. The triad of Phemister is reemphasized, and the US and MRI findings are demonstrated. The definitive diagnosis has to be made by culturing biopsied synovium or synovial fluid.

Herbicide/pesticide effects on intestinal epithelial growth

The purpose of the present study was to examine the effects of some common herbicides and pesticides on the growth of normal intestinal and colonic epithelial cells. Preconfluent cultures of normal rat intestinal cells (IEC-6 cell line) and normal human colonic epithelial cells were treated with 0.05-50 microM doses of atrazine, diazinon, and endosulfan. After 3 days of treatment, the change in cell proliferation was quantified by cell counting or the MTT growth assay. Both intestinal and colonic epithelial cell cultures had increases in cell growth when treated with as little as 1.0 microM atrazine, diazinon, or endosulfan. The observed changes in both cultured intestinal and colonic cell growth rates were not due to the influence of the vehicle control dimethyl sulfoxide (DMSO). That is, the treatment of the cell cultures with concentrations of DMSO as high as 0.5% for 3 days resulted in no change in cell growth compared with untreated control cultures. A consistent observation with all three of the compounds was that the highest doses (50 microM) had the least "proliferative potential" in stimulating either IEC-6 cell or human colonic epithelial cell growth. Within the concentration range used, none of the herbicides or pesticides caused a decrease in cell proliferation below that of the untreated control cultures. Overall, treatment of IEC-6 cell cultures with atrazine, diazinon, or endosulfan produced a biphasic growth response, whereas the same treatment in the human colonic epithelial cell cultures produced a more sustained level of growth over the same period. This culture system may provide the basis for an in vitro model to further study the cellular and molecular basis of the effects of herbicides and pesticides on intestinal epithelial proliferation.

Excisional biopsy of impalpable soft tissue tumors. US-guided preoperative localization in 12 cases

We present a technique to facilitate excisional biopsy of impalpable soft tissue tumors. A modified Kopans localization needle is positioned preoperatively under ultrasound-guidance (7.5 MHz). The needle contains a hookwire with an over-bent hook that springs open when protruded beyond the needle tip and anchors the wire in the lesion. The technique was used in 12 patients and facilitated excisional biopsy in all of them.

Establishment of human colonic epithelial cells in long-term culture

Study of normal colonic function is important in understanding the cellular mechanisms of carcinogenesis and other diseases of the colon. However, colonic pathophysiological studies have been limited due to the lack of long-term cultures of normal human colonic epithelial cells. The purpose of the present study was to develop methods of isolating viable human colonic epithelial cells for the establishment of nontransformed colonic epithelial cell lines. Human colonic epithelial cells were isolated from surgically resected normal human colons. We found that the use of a short enzymatic digestion gave a consistently higher number (>90%) of viable human colonic epithelial cells. These isolated colonocytes were grown on plastic, collagen-coated filters, or feeder layers using different media formulations. Those colonocytes from the initial primary cultures that were most "epithelial" in appearance were cloned and passaged to establish long-term cultures of nontransformed human colonic epithelial cells. The epithelial nature and secretory function of these established cell lines were confirmed by morphological criteria (light microscopy,, phase contrast microscopy, and electron microscopy). We found that the long-term cultures remained immunopositive to anti-cytokeratin antibodies and immunonegative to anti-vimentin antibodies. Using a soft agar assay we found that the colonocytes did not form colonies, suggesting that the long-term culturing did not cause these cells to become transformed. Under serum-free conditions, we found that epidermal growth factor and transforming growth factor-alpha were equally potent in their mitogenic effects for these colonocytes. Some of the subcultured cells could be maintained for at least 8 months and still retain their epithelial characteristics. We believe that this methodology will serve as a valuable tool for the isolation and culturing of human colonic epithelial cells for studies of normal and malignant colonic disease processes.

Identification of an EGF/TGF-alpha receptor in primary cultures of guinea pig gastric mucous epithelial cells

Binding and localization of transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) were assessed using in vitro primary cultures of guinea pig gastric mucous epithelial cells (GMEC). GMEC were isolated and cultured in six-well plates with Dulbecco's modified Eagle's medium + 10% serum and then changed to serum-free medium for 24 h for binding studies. The binding time course of 125I-labeled EGF and 125I-TGF-alpha in GMEC cultures at 4 degrees C was saturable, reaching a plateau within 4-6 h. Competition-binding curves revealed that the amount of unlabeled EGF and TGF-alpha to reduce 125I-EGF binding by 50% was 0.35 and 0.23 nM, respectively. The amount of unlabeled EGF and TGF-alpha to decrease 125I-TGF-alpha binding by 50% was 0.30 and 0.21 nM, respectively. A Scatchard analysis of the data disclosed that a single class of high-affinity binding sites (dissociation constant = 0.24 nM) was present. The maximal binding capacity was approximately 20 fmol/10(6) cells or approximately 12,000 receptors per cell. The binding of 125I-EGF and 125I-TFG-alpha to GMEC cultures was maximal between pH 7.0 and 8.5. No specific binding of EGF or TGF-alpha could be detected below pH 5.0. The half-maximal pH dissociation value for EGF and TGF-alpha was pH 5.89 and pH 6.83, respectively. We found no difference in the final amounts of membrane-bound or internalized 125I-EGF and 125I-TGF-alpha. However, there was a significant difference (P < 0.05) at 5-30 min in the rate of dissociated and internalized 125I-EGF- and 125I-TGF-alpha. Immunofluorescence microscopy of GMEC cultures for EGF/TGF-alpha receptors showed increased fluorescence at the leading edges and around the perimeter of cells. Detection of an EGF/TGF-alpha receptor was also confirmed by Western blotting. Our findings demonstrate that guinea pig GMEC possess a specific EGF/TGF-alpha receptor, which further supports a physiological role for EFG and TFG-alpha as mitogens in these cells.

TGF-alpha is a potent mitogen for primary cultures of guinea pig gastric mucous epithelial cells

Transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) are thought to be important in gastric epithelial proliferation and repair. It was therefore of interest to determine if TGF-alpha and EGF promoted the growth of an in vitro primary culture system of guinea pig gastric mucous epithelial cells (MEC). MEC were isolated from guinea pig stomachs and cultured in 24-well Primaria plates with DMEM with or without 10% fetal calf serum (FCS). Growth of MEC was determined by changes in [3H]thymidine uptake, cell counts, protein, and DNA. The sources of peptides were human recombinant TGF-alpha (recTGF-alpha) and human recombinant EGF (recEGF). Both recTGF-alpha and recEGF were used at equipotent doses as determined by competing activity in a 125I-labeled TGF-alpha radioreceptor binding assay using A-431 cells. Basal growth (no peptides) of MEC in 10% FCS was dependent on the initial plating density. Under serum-free conditions, [3H]thymidine uptake increased up to 17-fold at 24 h with recTGF-alpha (0.1-10.0 nM) compared with only a 4-fold increase using rec-EGF (0.1-10.0 nM) at this same time period. Under serum-free conditions, recTGF-alpha (0.01-10.0 nM) increased cell counts up to 4.9-fold over control cultures, whereas similar does of recEGF produced a 2.5-fold increase in cell counts. Administration of recEGF 1 ng/ml) resulted in a 1.9-fold increase in the 4.8-kb TGF-alpha mRNA transcript, and TGF-alpha protein immunoreactivity was found in both 24-h conditioned media and cell lysates.(ABSTRACT TRUNCATED AT 250 WORDS)

Adherence of Candida albicans to immobilized extracellular matrix proteins is mediated by calcium-dependent surface glycoproteins

The adherence of Candida albicans to the extracellular matrix proteins type I collagen and fibronectin (Fn) is dependent upon the presence of extracellular calcium. In the absence of calcium, 14 +/- 3% of yeast cells added to type I collagen adhered, whereas 62 +/- 3% of yeast cells adhered in the presence of 2 mM calcium. EDTA and EGTA reduced C. albicans adherence in a dose-dependent manner. Calcium, and to a lesser extent, cesium and magnesium, enhanced yeast cell adherence. The fluorescent probe, terbium (Tb+3), bound to the surface of yeast cells in a dose-dependent manner demonstrating the presence of cationic metal-binding sites on the yeast cell surface. When extracts of C. albicans yeast cells were applied to columns of Fn or gelatin coupled to agarose, two surface proteins of C. albicans were specifically eluted with 10 mM EDTA, 2% alpha-methylmannopyranoside or an Arg-Gly-Asp-containing peptide. The fungal proteins had relative molecular masses of 60,000 and 105,000 in the unreduced state. The proteins were present in the cell membrane as well as the cell wall and were demonstrated to be glycoproteins by their ability to bind concanavalin A. Immunoblot analysis of yeast extracts demonstrated that anti-integrin antibodies to the human fibronectin, vitronectin and complement receptor cross-reacted with the Candida 60 kDa glycoprotein. Thus, calcium-dependent fungal cell wall glycoproteins likely related to integrins may be receptors responsible for yeast cell adherence to host tissue such as the extracellular matrix.

Insulin enhances epidermal growth factor- and transforming growth factor-alpha-stimulated growth in primary cultures of guinea pig gastric mucous epithelial cells

The effect of insulin on epidermal growth factor (EGF)- and transforming growth factor-alpha (TGF alpha)-induced cell proliferation was examined in primary cultures of gastric surface mucous epithelial cells by using changes in cell counts and DNA as indices of cell growth. With 1.0% fetal bovine serum and Dulbecco's modified Eagle medium (low-serum DMEM) there was no effect of bovine insulin (0.1-10.0 micrograms/ml) on cell growth. Higher doses of insulin (20.0 micrograms/ml) in low-serum DMEM were able to stimulate growth of these cells compared with controls. In low-serum DMEM with no insulin the lowest effective dose of EGF or TGF alpha for stimulating cell growth was 10 nM and 5 nM, respectively. In low-serum DMEM containing 2.5 micrograms/ml insulin there was a dose-dependent increase in cell growth with EGF and TFG alpha at concentrations of 0.5-10.0 nM. The addition of insulin alone at 2.5 micrograms/ml, EGF alone at 2 nM, or TGF alpha alone at 2 nM in serum-free DMEM media had no effect on gastric surface mucous cell DNA. In serum-free DMEM media with 2.5 micrograms/ml insulin, the addition of 2 nM EGF or 2 nM TGF alpha caused an increase in both cell counts and DNA of 1.80- and 3.50-fold, respectively. The present study demonstrates that insulin, at concentrations that are not mitogenic, will enhance the proliferative effects of EGF and TGF alpha on the growth of primary cultures of guinea pig gastric surface mucous epithelial cells.

Low doses of ethanol have Ca2+ ionophore-like effects on apical membrane potential of in vitro Necturus antrum

The effects of low doses of luminal ethanol on the amiloride-sensitive apical membrane potential of Necturus antral mucosa were studied using conventional microelectrode techniques. Luminal ethanol (0.250-4.0% vol/vol) caused a dose-dependent hyperpolarization of the apical membrane potential (Vmc), an increase in transepithelial resistance (Rt) and resistance ratio (Ra/Rb), and a decrease in transepithelial potential (Vms). Luminal amiloride (100 microM) to 4% ethanol-treated antra did not cause any additional hyperpolarization of Vmc. Compared with luminal 2% ethanol-Ringer, an equivalent osmotic mannitol solution depolarized Vmc and basolateral potential (Vcs), decreased Rt and Ra/Rb, and increased Vms. A single dose of 0.50% ethanol attenuated the effects of a second 2% ethanol exposure on Vmc. No change in periodic acid-Schiff (PAS)-positive mucous granule content could be found between control and 2% ethanol-treated antra. The Ca2+ ionophores A23187 or ionomycin (0.25-5.0 microM) dose dependently hyperpolarized the Vmc and Vcs, increased Rt and Ra/Rb, and decreased Vms. Luminal Ca(2+)-free Ringer had no effect on luminal 2.00% ethanol-induced changes in membrane potentials or resistances. Pretreatment with BAPTA blocked by approximately 70 and 55% the Vmc hyperpolarization of 2 and 4% ethanol, respectively. Pretreatment with ruthenium red (10-50 microM) also dose dependently reduced the 2% ethanol-induced changes in Vmc. The data indicate that 1) low doses of luminal ethanol and Ca2+ ionophores have similar effects on Necturus gastric antral membrane potentials and resistances, 2) ethanol-induced hyperpolarizations of the Vmc are partially mediated through an alteration in intracellular Ca2+, and 3) low doses of luminal ethanol do not cause the release of antral epithelial mucous granules at the time when significant changes are occurring in the Vmc.

Gastric fundic mucous epithelial cells isolated from omeprazole-treated guinea pigs have increased basal and hormone-stimulated growth rates

Guinea pigs were given a daily oral dose of 400 micrograms/kg of omeprazole or the omeprazole vehicle for 6 weeks. At weekly intervals, the animal and stomach weights were recorded, the nonfasted serum gastrins measured, and the total number of gastric fundic epithelial cells were isolated and counted. Gastric mucous epithelial cells were enriched from the total gastric fundic cell population and cultured for 6 days in the absence or presence of hormones (epidermal growth factor and pentagastrin). We found that omeprazole treatment for 1-6 weeks significantly (p less than 0.05) increased the stomach weight, the nonfasted serum gastrin levels, and the total number of isolated gastric fundic and mucous epithelial cells over control animals. A significant (p less than 0.05) increase was also found in the basal and hormone-stimulated cultured growth rates of gastric mucous epithelial cells isolated from the stomachs of omeprazole-treated animals as compared with gastric mucous cells from control animals. We conclude that oral omeprazole treatment of guinea pigs will cause a specific increase in the gastric mucous cell population as well as increase the in vitro cultured gastric mucous cell basal and hormone-stimulated growth rates.

Physiological and cytotoxic effects of Ca(2+) ionophores on Caco-2 paracellular permeability: relationship of 45Ca(2+) efflux to 51 Cr release

The human intestinal cell line, Caco-2, and the Ca2+ ionophores, A23187 and ionomycin, were used to determine the interrelationships of 45Ca(2+) efflux, transepithelial electrical resistance (Rt), and [3H]-mannitol flux to changes in 51Cr release and lactate dehydrogenase (LDH) activity. Treatment of Caco-2 monolayers with ionomycin at concentrations of between 0.25 and 2.50 mumol/l showed similar 45Ca(2+) efflux rate constants and coefficients. Analysis of the control and ionomycin-induced 45Ca(2+) efflux values showed the data to best fit a three Ca(2+) compartmental model. All changes in Caco-2 Rt and [3H]-mannitol flux were reversible with no significant increases in 51Cr release with ionomycin concentrations of less than or equal to 2.5 mumols/l. Caco-2 monolayers treated with ionomycin at concentrations of between 5.0 and 50.0 mumols/l showed rapid non-exponential 45Ca(2+) effluxes with irreversible changes in Rt, [3H]-mannitol flux, and significant increases in 51Cr release. There was no changes in media LDH activity using either ionomycin or A23187 at concentrations of up to 50 mumols/l for 60 min. The results of our study show that: (1) disruption of Ca(2+) homeostasis in Caco-2 cells will occur with the addition of Ca(2+) ionophores at concentrations of greater than 2.50 mumols/l; (2) high concentrations (greater than 2.5 mumols/l) of ionomycin will cause non-exponential 45Ca(2+) efflux rates with irreversible changes in intracellular Rt and 14C-mannitol flux, and (3) early signs of Ca(2+) ionophore-induced damage can be detected by 51Cr release from Caco-2 cells into the media and not by changes in LDH media activity.

Feeding induces lipid accumulation and increased Na+ transport in in vitro Necturus antrum

We investigated the effects of feeding on lipid accumulation and transepithelial transport using in vitro Necturus gastric antral mucosae. Antra from fed Necturi were examined for lipid accumulation using light, fluorescence, histochemical, and electron microscopy. Ussing chambers were used for measurement of potential difference (PD), transepithelial resistance (Rt), short-circuit current (Isc), and unidirectional fluxes of 22Na+ and [3H]mannitol. Light microscopy of antra from 2-day postfed animals showed many intracellular lipid granules in surface mucous epithelial cells. These granules could be distinguished from other intracellular organelles by their high affinity for osmium and the lipid fluorescent probe Nile red. Glycoprotein cytochemical staining showed these granules to be distinct from the epithelial cell mucous granules. Electron microscopy showed the lipid granules to be part of a membranous reticular network. Two-day postfed animals also had a approximately 3.5-fold increase in amiloride-sensitive Isc and PD, a decrease in Rt, and an increased luminal-to-serosal Na+ fluxes. Transepithelial [3H]mannitol fluxes were low and remained unchanged in both fasted and 2-day postfed animals. After 2 days of feeding, the PD and Isc began to decrease followed by a secondary increase in Rt. Feeding Necturi a corn oil diet did not induce the appearance of either cellular lipid or alterations in Isc but produced a transient increase in Rt. Our data show that feeding (goldfish) to Necturi causes an increase in both lipid accumulation and amiloride-sensitive Na+ transport in gastric antral cells.

Electron-cytochemical localization of alkaline phosphatase to G cells of Necturus maculosus antrum

Electron-cytochemical localization of alkaline phosphatase activity was performed on G cells of Necturus maculosus antral mucosa. Alkaline phosphatase activity was localized to the nuclear membrane, the Golgi/endoplasmic reticulum, and the limiting membranes of G cell peptide-secretion vesicles. There was no specific localization of alkaline phosphatase activity to the plasma membrane. Treatment of the tissues with levamisole (an alkaline phosphatase inhibitor) did not markedly reduce the specific alkaline phosphatase activity. Specific lead deposition was reduced by removal of the substrate from the reaction mixture. The results from this study on N. maculosus G cells demonstrate that alkaline phosphatase activity can be found in a non-mammalian gastric endocrine cell and that specific activity was localized primarily to those intracellular structures involved with protein biosynthesis.

Effects of parathyroid hormone on cyclic-AMP concentrations of in vitro Necturus maculosus gastric antrum

The effects of bovine parathyroid hormone (bPTH1-84) on the stimulation of intracellular cyclic-AMP [cAMP] were investigated in an in vitro preparation of Necturus maculosus antral mucosa. When the antrum was exposed to 1, 5, 10, or 100 nM bPTH1-84, there was an approximately 2-fold nonlinear increase in tissue [cAMP] over basal values. The pretreatment of the antral mucosa with 1 mM isobutylmethylxanthine (IBMX, a phosphodiesterase inhibitor) increased with detectability of mucosal [cAMP]. The addition of 1, 5, 10, or 100 nM bPTH1-84 to tissues pretreated with IBMX resulted in an approximately 3.5-fold linear increase in mucosal [cAMP] over basal values. The time course of the generation of mucosal cAMP to 10 nM bPTH1-84 resulted in a small but significant transient increase at 2.5 min after the addition of bPTH1-84 but no change in the medium [cAMP]. In tissues pretreated with 1 mM IBMX the response to 10 nM bPTH1-84 was a large biphasic increase of [cAMP] at 2.5 min that progressively declined to near basal values by 15 min. There was also a significant sustained increase in the [cAMP] in the bathing medium at 2.5 min of tissues pretreated with IBMX followed by 10 nM bPTH1-84. These results suggest the presence of an adenylate cyclase that can be activated by a mammalian bPTH1-84 in elevating intracellular cAMP levels in the N. maculosus antral mucosa.

Effects of cations and pH on apical membrane potential of in vitro Necturus antrum

The surface epithelial cells of the gastric mucosa transport Na+ from lumen to serosa. The first step in this process is the entry of Na+ through an amiloride-sensitive Na+ channel at the apical membrane. The exact function(s) of this Na+ transport are unknown, but it has been suggested that it might help the stomach to withstand an acid load. The present study was undertaken to examine the effects of low luminal pH and the alkali cations Li+, K+, Rb+, and Cs+ on the amiloride-sensitive Na+ permeability of the apical membrane of Necturus antral cells by measuring the changes in apical membrane voltage (Vmc) using conventional microelectrode techniques. Isosmolar replacement of luminal NaCl (pH 7.25) with LiCl caused a depolarization of the Vmc, a decrease in transepithelial resistance (Rt), and an increase in the transepithelial potential (Vmc), whereas replacement with KCl, RbCl, or CsCl caused a hyperpolarization of the Vmc, an increase in Rt, and a decrease in the Vmc. Luminal acidification from pH 7.25 to pH 3.00 caused very similar changes with all the cation solutions tested, hyperpolarizing the Vmc, increasing Rt, and reducing the Vmc to near 0 mV. Acidification of the luminal NaCl solution from pH 7.25 to pH 2.00 caused a progressive hyperpolarization of the Vmc similar to the effects seen with luminal amiloride (10(-4) M) in pH 7.25 NaCl solutions or luminal Na+-free (N-methyl-D-glucamine) Ringer at pH 7.25. These results demonstrate that 1) of the cations tested only Li+ can substitute for Na+ in maintaining the Vmc, and 2) external H ions (low luminal pH) block cation permeability of the apical membrane.

Electrical resistance and macromolecular permeability of brain endothelial monolayer cultures

Electrophysiological measurements were made on endothelial cells initially isolated as individual clones from bovine brain microvessels, and then grown as monolayers on a permeable support of glutaraldehyde-treated collagen gel. When transendothelial cell resistance (R) of the clones was measured, there was a range of values from a low of 157.4 +/- 4.5 omega.cm2 (n = 6) to a high of 783.2 +/- 7.0 omega.cm2 (n = 34). With the high-resistance cells, there was also a small potential difference of -0.46 +/- 0.03 mV luminal-side negative (n = 34). In comparison, endothelial cells from bovine aortas and rat epididymal fat pads cultured on the collagen gels had transendothelial R values of 13.5 +/- 0.2 (n = 62) and 0.45 +/- 0.03 (n = 10) omega.cm2, respectively. Exposure of the high-resistance brain endothelial cell monolayers to a Ca2+-free medium for 10 min decreased the R to 75% of the control values. Addition of Ca2+ back to the medium caused a return of the transendothelial R to control values within 1 h. Endothelial cells were also grown to confluency on microcarrier beads for permeability measurements to Evans blue dye-bovine serum albumin. Microcarriers with no cells (control) and microcarriers with bovine and epididymal endothelial cell monolayers showed no difference in the amount of adsorbed dye. Microcarriers with brain endothelial monolayers excluded up to 80% of the dye. This mammalian brain endothelial culture system will be a useful model for studies of the electrophysiological and permeability properties of the blood-brain barrier.

Structural and functional changes by ethanol on in vitro guinea pig gastric mucosa

Relationships between morphological and electrophysiological changes with low concentrations of ethanol on in vitro guinea pig gastric mucosa were investigated. Tissues mounted in Ussing chambers allowed recording of transepithelial potential difference (PD), resistance (R), short-circuit current (Isc), and acid secretion (H+). At selected times the mucosae were processed for morphological analysis. With luminal 10% ethanol there was a decrease in PD, R, Isc, and H+ within 1 min, and they eventually went to low steady-state values between 10 and 40 min. At 1 min many surface epithelial cells lifted off from the basal lamina but were still anchored by thin basal cell processes. After 10 min in ethanol many surface cells had completely detached from the basal lamina but remained connected to adjacent cells by their junctions. Numerous cytoplasmic blebs formed on both apical and basal cell surfaces. Concurrently, there was a significant increase in microvillus length. After 40 min most of the surface cells were detached from the basal lamina as sheets forming epithelial blisters. Upon ethanol washout there was epithelial cell reattachment to the basal lamina and a return of the PD, R, and Isc to control values within 40 min. Incubation of the luminal surface with 10% ethanol for 5 h resulted in a gradual rise of the PD, R, Isc, and H+ to control values by 4 h with a coincident return of the normal mucosal morphology. These studies indicate that ethanol has reversible and possibly adaptable effects on the in vitro guinea pig gastric mucosa and that the morphological changes are closely correlated with the decline and recovery of the electrical and secretory activity of the tissue.

A rapid method for culturing guinea pig gastric mucous cell monolayers

A method has been developed for growing confluent primary cultured monolayers of guinea pig gastric mucous cells suitable for in vitro electrophysiological, transport, and pharmacological studies. Isolated mucous cells were enriched on a one-step Percoll density gradient and plated on fibronectin-coated plastic dishes or in small cups with holes containing glutaraldehyde-fixed Vitrogen gels. These cups were designed to fit in Ussing chambers. Mucous cells attached, proliferated, and formed confluent monolayers in 3 d. The low cuboidal cells contained periodic acid Schiff-positive mucous granules that were negative by Bowie and indirect immunofluorescent staining for pepsinogen. Electron microscopy revealed polarized mucous cells with microvilli, mucous granules, microfilaments, small mitochondria, some vacuoles, and junctional complexes that excluded wheat germ agglutinin-peroxidase. No basal lamina was present. Monolayers could be maintained for over 2 wk but subcultures were not made. The cultures were virtually free of fibroblasts. Epithelial sheets produced by this simple and rapid method can be used for electrophysiological, ion transport, and pharmacological studies.

Rapid repair of injured gastric mucosa

The morphology of the rat gastric mucosa superficially damaged by a 30-45 sec exposure to 100% ethanol caused over 99% of the luminal surface to be necrotic without extensive hemorrhage or hyperemia. However, this damaged area restituted or rapidly healed and the process was described. These findings were compared with in vitro gastric mucosae of bullfrogs and guinea pigs which were damaged with 1 or 1.25 M NaCl and allowed to restitute. The rat gastric mucosa showed evidence of cell migration within 5 min after ethanol damage and after 15 min as much as 50% of the denuded basement membrane was restituted. After 30 min about 75% of the mucosa was covered with cells and by 1 h there were only minor epithelial discontinuities. The in vitro frog mucosal restitution after hypertonic injury was slower and required 1-2 h to show appreciable cell migration and 4-6 h for completion of the repair process. Using chambered guinea pig gastric mucosa damaged with hypertonic NaCl restituted the necrotic surface almost as rapidly as the intact rat stomach necrotized with absolute ethanol. Since prostaglandin treatment did not prevent ethanol or hypertonic salt injury or affect the restitution process it was proposed that the term cytoprotection as it is generally used is not appropriate.

Morphology and electrophysiology of guinea pig gastric mucosal repair in vitro

Guinea pig gastric mucosae stripped of their outer muscle layers were studied in Ussing chambers for up to 14 h. Ten minutes after the mucosae were mounted in the chamber, the electrical parameters were low but continued to rise over 90 min until steady-state potential difference (PD), resistance (R), and short-circuit current (Isc) were recorded. Morphological analysis during the first 10 min of the tissue in the chamber revealed gaps in the epithelium due to damaged cells. However, tissues examined after 20 min in the chamber showed little evidence of epithelial discontinuity. Thereafter, the initial rise in the electrical parameters was noted. After steady-state attainment, the lumen was exposed to 1.25 M NaCl for 5 min and then changed back to 150 mM NaCl. Ten minutes after washout and return to control solutions, the PD, R, and Isc had fallen to low values. At 30 min after washout of the NaCl, the PD, R, and Isc began to increase and after 2 h were back to control values. Morphological analysis of mucosae fixed up to 10 min after exposure to 1.25 M NaCl showed extensive damage and exfoliation of surface cells. However, by 30 min the epithelium was restored and had very few discontinuities, which was then followed by the return of the electrical parameters. The conclusions from these studies are 1) guinea pig gastric mucosae exposed to hypertonic NaCl on the luminal side will primarily result in surface epithelial cell destruction with an immediate drop in the transepithelial electrical values; 2) after return to isotonic saline the damaged mucosa can repair itself within minutes, which then allows the reestablishment of the transepithelial electrical parameters by 2 h; and 3) the good viability and reproducibility of this preparation present a suitable mammalian model system for the study of factors of mucosal repair.

Fetal rabbit gastric epithelial cells cultured on floating collagen gels

Cells were isolated from approximately 30 d fetal rabbit stomachs and cultured on floating collagen gels. Electron microscopy showed monolayers in which only one cell type persisted. These columnar cells were joined at apical borders by tight junctions and contained an extensive endoplasmic reticular network with an occasional intracellular canaliculus. They also occasionally contained what appeared to be secretory granules (mucus?), and therefore had some characteristics of all the cell types of the intact fetal stomachs, which showed oxyntic, mucous, and undifferentiated cells. In Ussing chambers with Ringer's solution on both sides, cultures developed transepithelial potential (potential difference [PD], mV, mucosa ground) = 13, resistance (resistance [R], omega - cm2) - 285, and short-circuit current (Isc, microA/cm3) = 45 (n = 7), clearly indicating that cellular polarity and junctional integrity were maintained. These transport parameters were somewhat different for intact fetal stomachs (PD = 20, R = 70, and Isc = 220 [n = 4]), which may be due to extensive folding of intact fetal stomachs or the presence of only one cell type in culture, or both. Although gastric stimulants histamine, dibutyryl cycle AMP (dbcAMP), and isobutylmethylxanthine (IMX) (a phosphodiesterase inhibitor) did not elicit H+ secretion or electrophysiological changes in monolayers or intact stomachs, 10-4 M apical amiloride caused a decrease in Isc in cultured monolayers(27%) and intact stomachs (50%). Thus, Na+ transport seems to be a significant fraction of ion transport in both preparations. This culture system may allow the study of oxyntic cell differentiation and the development of H+, Na+, and Cl- transport in the gastric musoca.

Histamine, cAMP, and activation of piglet gastric mucosa

The involvement of cAMP as a second messenger for histamine-induced H+ secretion was studied in a physiologically active, in vitro preparation of piglet gastric mucosa. During the first 5--10 min of stimulation with either histamine or the cAMP phosphodiesterase inhibitor 3-isobutyl-1,4-methylxanthine (IBMX), increases (greater than or equal to 5-fold) in tissue cAMP content [(c-AMP]) were well correlated with the characteristic decrease in transepithelial resistance (R); these changes precede H+ secretion by several minutes. Control experiments indicate that, during these treatments, tissue [cAMP] is dominated by the [cAMP] of oxyntic cells alone; change in R and H+ are also related to activity of these cells alone. At the steady state (45 min), histamine and IBMX caused equivalent increases in H+ and decreases in R, but [cAMP] was markedly different in the two cases. With IBMX [cAMP] was elevated at least fivefold, whereas with histamine [cAMP] was less than or equal to 50% above resting levels. The tissue is also stimulated by exogenous additions of dibutyryl cAMP. A histamine-sensitive adenylate cyclase was present in isolated, purified oxyntic cells. The histamine sensitivity of the cyclase was very similar to that which the intact tissue exhibits for histamine-induced changes in H+ and R. The cyclase activity was blocked by cimetidine but not by promethazine. We conclude that during stimulation histamine activates a histamine (H2)-sensitive adenylate cyclase of oxyntic cells, and there is a rapid increase in cellular [cAMP] that is involved in activation of H+ transport and other associated changes of oxyntic cells. An active phosphodiesterase is responsible for reducing [cAMP] to a level much below the "peak" value. Other cellular factors (e.g. protein kinases and Ca2+-calmodulin) must also be involved in the maintenance of the stimulated state of oxyntic cells.