Malignant progression of a mouse fibrosarcoma by host cells reactive to a foreign body (gelatin sponge)

The QR regressor tumour (QR-32), a fibrosarcoma which is unable to grow progressively in normal syngeneic C57BL/6 mice, was able to grow progressively in 13 out of 22 mice (59%) when it was subcutaneously coimplanted with gelatin sponge. We established four culture tumour lines from the resultant tumours (QRsP tumour lines). These QRsP tumour lines were able to grow progressively in mice even in the absence of gelatin sponge. The ability of QRsP tumour cells to colonise the lungs after intravenous injection and to produce high amounts of prostaglandin E2 (PGE2) during in vitro cell culture was much greater than that of parent QR-32 cells. These biological characteristics of QR-32 cells and QRsP tumour cells were found to be stable for at least 6 months when they were maintained in culture. We also observed that QR-32 cells were able to grow progressively in five out of 12 (42%) mice after coimplantation with plastic non-adherent peritoneal cells obtained from mice which had been intraperitoneally implanted with gelatin sponge. These host cells reactive to gelatin sponge increased the production of high amounts of PGE2 by QR-32 cells during 48 h coculture. Preliminary in vitro studies implicated the involvement of hydrogen peroxide and hydroxyl radical as some of the factors necessary to induce QR-32 cells to produce high amounts of PGE2 and to accelerate tumour progression.

Progression of weakly malignant clone cells derived from rat mammary carcinoma by host cells reactive to plastic plates

Tumor progression is the process by which tumor cells acquire more malignant properties, such as invasiveness and metastasis, during tumor development. To elucidate mechanisms of tumor progression, we examined the role of interactions between the tumor and its host by using a cloned cell line, ER-1, which was derived from a rat mammary carcinoma. ER-1 is weakly tumorigenic and non-metastatic when s.c. injected into syngeneic hosts in single cell suspension. However, ER-1 cells show a high incidence of lethal growth when s.c. implanted (5 x 10(2) cells), being attached to a 10 x 5 x 1 mm polystyrene plate. Tumor cell lines (PLT) obtained from tumors which had arisen from the plate-attached ER-1 cells no longer required plates for their growth in normal hosts, and had acquired metastatic ability to the lungs. The malignant phenotypes of PLT were stable under a usual culture condition for at least 6 months. Furthermore, the incidence of tumor development increased when small numbers of ER-1 cells were injected onto plates (or at their periphery) which had previously been implanted s.c. without tumor cells. The tumorigenicity of ER-1 cells increased after they were cocultivated for more than 30 days with host reactive cells obtained from the tissues surrounding the plates. These results suggest that host cells reactive to the foreign body (plastic plate) may not only promote the local growth of ER-1 cells but also convert them into much more malignant tumors.

Calcitonin gene-related peptide: mechanisms of modulation of antral endocrine cells and cholinergic neurons

Actions of human calcitonin-gene related peptide (hCGRP) on acetylcholine (ACh) discharge and gastrin and somatostatin release from rat antral mucosal-submucosal fragments were examined in both dynamic perifusion experiments and short-term static incubation studies. The principal findings of the dynamic perifusion experiments were that hCGRP exerted a dual or biphasic effect on ACh discharge and gastrin release. Initial exposure of antral tissues to hCGRP (1 x 10(-8) M) resulted in stimulation of both ACh and gastrin release that was of brief duration. Continued hCGRP perifusion caused subsequent inhibition of ACh and gastrin release that was substantially greater in duration and magnitude than the initial stimulatory responses. Static incubation studies indicated that hCGRP (10(-10) to 10(-7) M) stimulated somatostatin and inhibited gastrin release in a dose-dependent manner. Inhibition of gastrin and ACh release by hCGRP appeared to be an indirect effect that was mediated by somatostatin as suggested by studies with pertussis toxin (200 ng/ml). Furthermore, studies with atropine (1 x 10(-6) M) and tetrodotoxin (1 x 10(-6) M) indicated that CGRP-induced stimulation of somatostatin release and inhibition of ACh discharge occurred independent of muscarinic receptor activation and nerve excitation. In conclusion, results of these studies indicate that CGRP is capable of exerting both stimulatory and inhibitory effects on ACh release from mucosal-submucosal neurons and gastrin release from antral mucosal G cells in in vitro studies. These data suggest that the inhibitory effects of CGRP on cholinergic discharge and gastrin release are due to the paracrine effects of somatostatin released from antral D cells by direct action of CGRP.

Mechanisms of airway protection and upper esophageal sphincter opening during belching

The mechanisms of airway protection, upper esophageal sphincter (UES) opening, and their coordination during belching were studied with a concurrent videoendoscopic, videofluoroscopic, and manometric technique. Analysis of videoendoscopic recordings revealed that glottal function during gastric and esophageal belching was similar and consisted of vocal cord adduction resulting in closure of intoitus to trachea, followed by anterior-caudad movement of the glottis, followed by slitlike or triangular UES opening. When a belch episode was associated with an intragastric pressure increase, in addition to the above features, there was approximation of arytenoids to the base of the epiglottis before the UES opened. Duration of vocal cord closure during belches induced by 40 ml intraesophageal air injection was significantly longer than belches induced by 20 ml (P less than 0.01). Vocal cord closure preceded the UES opening invariably. Analysis of videofluoroscopic recordings showed that hyoid bone movement during belching had a distinctive pattern different from its movement during swallowing. UES opening started generally when the hyoid bone was pulled anteriorly. Anterior hyoid excursion of 0.78 +/- 0.1 cm during belching was significantly shorter than its excursion of 1.8 +/- 0.09 cm during swallowing (P less than 0.01). We conclude that glottal closure is an integral component of both esophageal and gastric belch reflexes that prevents aspiration of regurgitated material into the airway. Glottal closure mechanism during belching has two tiers of closure: 1) vocal cord closure and 2) aryepiglottic approximation. Glottal and UES functions are closely coordinated during belching, and finally, during belching, UES is pulled open after its relaxation.

Esophagoglottal closure reflex: a mechanism of airway protection

Abrupt esophageal distention occurs commonly during gastroesophageal reflux, thereby generating a circumstance favorable to esophagopharyngeal regurgitation and laryngeal aspiration of gastric refluxate. The aims of the present study were to examine the glottal response to esophageal distention by air and regional esophageal distention by a balloon. Fifteen healthy volunteers (age, 25 +/- 5 years) were studied while they were in an upright position. Using concurrent videoendoscopy and manometry, glottal and upper esophageal sphincter (UES) responses to abrupt esophageal distention by air injection (10-60 mL) and balloon distention (1.5, 2.0, and 2.5 cm) were recorded simultaneously. In addition, 6 subjects were studied with concurrent synchronized videofluoroscopy. Results showed that esophageal distention by air at a threshold volume of 10-60 mL caused vocal cord closure. The UES response to this threshold volume was variable. Volumes larger than the threshold value caused complete UES relaxation and belching. In addition to vocal cord closure, belching was accompanied by anterior movement of the glottis. On videofluoroscopy, the hyoid bone moved anteriorly in association with belching, but not with vocal cord closure without belching. Proximal esophageal distention by the balloon also provoked vocal cord closure. This response was less consistent for balloon distention in the middle and distal esophagus. It is concluded that (a) esophageal distention by either air or a balloon evokes a glottal closure mechanism, thereby suggesting the existence of an esophagoglottal reflex; (b) this reflex is elicited most easily by distention of the proximal esophagus; (c) glottal and UES responses to esophageal distention are independent from each other; and (d) the esophagoglottal closure reflex may play an important role in preventing laryngeal aspiration of acid due to gastroesophageal reflux accompanied by acid regurgitation into the pharynx.

Validation of the antral mucosal/submucosal sleeve preparation: studies of gastrin and acetylcholine release in response to luminal stimulation

In the present study we developed an experimental model for direct assessment of antral endocrine cell and cholinergic neural responses to luminal stimulation. A sleeve of antral mucosal/submucosal tissue was prepared from rat antrum, mounted in perfusion chamber, and perfused in both luminal and submucosal compartments. Morphological and functional integrity of the antral sleeve were confirmed by histological examination and measurement of protein synthesis. Antral gastrin release was assessed in response to luminal stimulation with acid, peptone and distension. Luminal acid (pH3) inhibited basal gastrin release by -70.4% and luminal peptone stimulated gastrin release to 210% above control (p < 0.02). Distention of the antral sleeve by hydrostatic pressure (3-25cm H2O) caused stepwise and significant increase in gastrin release that was reversible. 3H-acetylcholine was stimulated significantly by KCl (56mM) to values twice control. In summary, these results establish the integrity and responsiveness of the antral sleeve to pharmacological and luminal stimulation. The antral sleeve may be a useful model in assessing antral function in response to luminal stimulation.

Correlation between the presence of microvilli and the growth or metastatic potential of tumor cells

We used an electron microscope to examine microvilli which appear on the surfaces of various tumor cells with high or low growth potential and/or metastatic ability. The results show that a greater number of microvilli appeared on the surfaces of tumor cells (QRpP and ERpP) which possess high growth potential than on tumor cells (QR and ER) with low growth potential. We also observed that microvilli were more abundant on the surface of highly metastatic clone cells, i.e. c-SST-2 (cl-2), mouse B16 melanoma (F-10) and human colon carcinoma (KM12SM) than on weakly metastatic clone cells, c-SST-2 (cl-4-2), B16 (F-1) and (KM12C). At the same time, more microvilli were observed on the surface of B16 BL6 cells, which were obtained from the metastatic site of the B16 F10 cells, than on the surface of the parent B16 F10 cells. Immunoelectron microscopy revealed that the c-neu oncogene product, which is closely related to an epidermal growth factor receptor, was positively stained in the microvilli of tumor cells (ERpP) with high growth potential and high metastatic ability, whereas the tumor cells (ER) with low growth potential and weak metastatic ability were not stained. These findings suggest that the increased presence of microvilli correlates closely with the growth potential and metastatic ability of tumor cells.

Preliminary study on the microbiology of Campylobacter pyloridis and gastric histopathology

Biopsy samples were taken endoscopically from the antral-mucosa of 693 patients with peptic ulcer and chronic gastritis presenting dyspepsia symptoms. Campylobacter pyloridis cultures were positive in 59 of 98 (60.2%) cases and histopathologically the organisms were found in 411 of 693 cases (59.3%). Pathologically, Campylobacter pyloridis was positive in 273 out of 300 patients with chronic superficial gastritis (91.0%), in 102 of 249 patients with chronic atrophic gastritis (40.9%), in 36 out of 144 patients with chronic atrophic gastritis with intestinalization or dysplasia (25.0%). We found that there was a significant association between the presence of Campylobacter pyloridis and chronic superficial gastritis, also the degree of lymphocyte infiltration showed a strong inverse association with the presence of Campylobacter pyloridis, suggesting that a local immune response might exert an important action in the eradication of this organism. These findings support the view that Campylobacter pyloridis, may be etiologically related to chronic gastritis and peptic ulceration, even though its role still remains to be determined.

[Pest control and yield increase of areca by root-zone application of carbofuran in admixture with fertilizers]

The result of our experiment has shown that by root-zone application of carbofuran in admixture with fertilizers to Areca in spring the serious pest Tirathaba rufivena can be controlled for 4 months during flowering and young fruiting stage and the yield can increase by 50%. The final residual amount of carbofuran in fruits is below 0.1-0.01 ppm or too low to be examined, and there is no decrease in total alkaloid content in fruits.

Modulation of feline esophageal contractions by bolus volume and outflow obstruction

We studied the effect of bolus volume and esophageal obstruction on esophageal peristalsis by using synchronized video-fluoroscopic and manometric techniques in cats. A specially designed pressure cuff was surgically implanted around the distal esophagus to control the degrees of outflow obstruction. Secondary esophageal peristalsis was evoked by injecting bolus volumes of 3, 6, and 9 ml at cuff pressures of 0, 20, 40, and 60 mmHg. Increases in outflow obstruction reduced the velocity of peristalsis. The amplitude of esophageal contraction increased with increasing outflow obstruction at low bolus volumes but decreased with larger bolus volumes and larger outflow obstruction. In the absence of outflow obstruction, each esophageal contraction traversed the entire esophagus distal to its site of origin, but in the presence of outflow obstruction contractions only traversed part of the esophagus. The incidence and site of failure of propagation was directly related to cuff pressure and bolus volume. The relationship between the onset of manometric pressure complex at a given site in the esophagus to the passage of the bolus from that esophageal site was markedly affected by outflow obstruction. We conclude that esophageal peristalsis can be modulated by the bolus volume and outflow obstruction.

Ultrastructural differences in junctional intercellular communication between highly and weakly metastatic clones derived from rat mammary carcinoma

We examined by electron microscopy the differences in junctional intercellular communications among highly metastatic clones, weakly metastatic clones, and the parent clone obtained from a spontaneously developed rat mammary carcinoma. We also investigated intercellular communications of the highly and weakly metastatic clone cells with normal fibroblasts. The results showed that ultrastructural changes of the highly metastatic clone cells, such as microvilli, microfilaments, and small organelles including endoplasmic reticulum, Golgi apparatus, and mucous particles, were more distinct than those of the weakly metastatic clone cells, and that the numbers of desmosome and gap junctions of weakly metastatic clone cells were significantly greater than those of highly metastatic clone cells. The formation of gap junctions and desmosomes was found only between weakly metastatic clone cells and normal fibroblasts. When both highly and weakly metastatic clone cells were cultured with normal fibroblasts, a tight junction was observed only in the culture of weakly metastatic clone cells and normal fibroblasts. These results suggest that ultrastructural differences are related to the proliferation and detachment of tumor cells from the primary site in the initial stage of tumor metastasis.

Movement of wax particles by contractions in the isolated opossum esophagus

We investigated whether the contractions of the isolated smooth muscle opossum esophagus can propel luminal contents. Wax particles were placed into the esophagus in vitro, and esophageal contractions were evoked by stimulating either primarily the intrinsic esophageal nerves (using electrical pulses of 0.5 ms) or the esophageal muscle directly (using pulses of 0.5 s). Direct muscle stimulation and neural stimulation produced circular muscle contractions of similar amplitude, but only neural stimulation was associated with a propagating ring contraction and longitudinal muscle contraction. Movement of the wax particle occurred after 21% of all stimulus responses. Aborad movement of the wax particle was 10 times as common as was its orad movement. Wax movement occurred less commonly and over shorter distance with muscle as compared with neural stimulation. The distance the wax moved was enhanced when the esophagus was allowed to shorten in its longitudinal axis. Movement occurred late during the contraction response and at velocities less than that of the ring contraction. Also, the ring contraction passed over the particle. The amplitude of circular muscle contractions had no predictive value for the occurrence of propulsion. The finding that the isolated esophagus can propel luminal contents in the aborad direction supports the thesis that peristalsis is primarily a function of the intrinsic neuromuscular organization of the smooth muscle esophagus.

Motility changes in opossum esophagus from experimental esophagitis

We assessed how acute inflammation affects the contractile activity of the esophageal body. Two models of esophagitis were used: nine opossums had an esophageal perfusion of 100 meq hydrochloric acid for 2 hr and were studied at 24 hr. Ten had the perfusion for 4 h and their esophagitis were studied in vitro after 72 hr. Comparisons were made in all instances to animals who had esophageal saline perfusion for identical periods. All acid-perfused animals developed gross and histologic evidence of mucosal inflammation; in three animals, inflammatory changes extended into the submucosa and the muscularis propria. Manometric recordings in the acid-perfused animals revealed esophageal shortening, frequent failure of primary peristalsis and frequent occurrence of spontaneous contractions. Recordings of isometric tension of muscle in vitro revealed spontaneous contractions in strips from the mucosa and from the circular and from the longitudinal muscle. The amplitude of contractions in response to electrical stimulation was decreased, but the duration of contractions was increased largely because of a prolonged recovery phase. These changes in mechanical response occurred with stimulus parameters directed at both the muscle and the intrinsic nerves. We conclude that esophageal inflammation can lead to an increased irritability and decreased stimulus response of the smooth muscle of the esophagus even where it is not directly involved in an inflammatory response. These changes correspond to the functional abnormalities of the esophagus seen in patients with reflux esophagitis.

Modulation of esophageal contractions by distension in vitro

Stimulation of the intrinsic nerves of the esophageal body leads to a twitch of the circular muscle after the end of the stimulation (the esophageal off-response), and the twitch spreads in the distal direction because of a latency gradient in the onset of the off-response between the proximal and the distal esophagus. We investigated the possibility that local input can modulate the basic off-response through intrinsic mechanisms and make it resemble more closely the sequential ring contractions that move boluses in the esophagus of intact animals (esophageal peristalsis). The esophagus up to the aortic arch and down to the gastroesophageal junction was removed from opossums and suspended in an organ bath containing 2 liters of Krebs solution at 36 degrees C. The mechanical activity of the esophagus was recorded by force transducers on the serosal surface of the esophagus 2, 4, and 6 cm above the LES. The intramural nerves of the proximal esophagus were stimulated by electrical pulses with and without distension of the esophagus by inflation of a luminal balloon. Balloon distension increased the latency of the off-response in the distal esophagus, thereby reducing the velocity at which the circular muscle contraction spread through the esophagus. In addition, balloon distension increased the amplitude and the duration of the esophageal circular muscle contraction (both off- and on-responses), and decreased the amplitude of the longitudinal muscle contraction (duration response) and LES response (relaxation response). Similar changes in the esophageal contraction responses were produced by radial stretch of an open preparation of the esophagus from which the mucosa had been removed.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for inhibition of opossum LES through intrinsic gastric nerves

We have studied the mechanical responses of the isolated opossum gastroesophageal junction to a variety of stimuli. Lower esophageal sphincter (LES) relaxations were readily produced by gastric stretch and by electrical stimulation of the intramural gastric nerves. Gastric stimulation also led in 60% of stimuli to a contraction of circular muscle (the off response) in the distal esophagus, but in less than 15% of stimuli to a contraction of longitudinal esophageal muscle (the duration response). Mechanical or electrical stimulation of the esophagus led to a mechanical response of the stomach (relaxation, contraction, or both) in 76% of stimuli. The LES relaxation produced by esophageal stimulation was not as long as that produced by gastric stimulation. Direct electrical stimulation of the esophageal or gastric muscle produced a ring contraction that spread readily across the gastroesophageal junction but did not produce a relaxation of the LES or a contraction of the longitudinal esophageal muscle. Thus intramural nervous pathways can coordinate the mechanical activity of the esophagus, LES, and stomach. LES relaxations may occur as part of intrinsic reflexes that mediate gastric accommodation to volume.