Effect of long term alcohol feeding on the pancreas in rat

To elucidate the pathophysiological process of alcoholic pancreatitis, chronic alcohol intoxication was made in Wistar rats on balanced diet giving 20% ethanol freely for 60 weeks. The control rats received water. Histological picture of the pancreas, hormonal activity in the mucosa of upper digestive tract and the nature of pancreatic juice were examined in every 15th week. The results were as follows. 1) No histological changes were noted in the pancreas of control group. In the ethanol group, morphological abnormalities of the pancreas appeared after 30 weeks. Of the histological findings, the changes on the ductal system such as dilatation of pancreatic duct, plug formation in the ductal lumen and periductal fibrosis were significant. 2) The long term ethanol administration tended to decrease the amounts of gastrin, secretin and cholecystokinin contained in the gastrointestinal mucosa. 3) Regardless of the histological changes of the pancreas, almost no changes were noted in the bicarbonate and protein concentration during the experimental period of 60 weeks. From the above results, a mechanism obstructing pancreatic ductal system is considered to be important in the pancreatic lesions by alcohol rather than a mechanism of stimulating pancreatic exocrine secretion.

[Evaluation of the reproducibility in radioactivity measurements with liquid scintillation counters--intercomparison among several presently available counters of different models (author's transl)]

Experimental studies were carried out to evaluate the reproducibility in 3H measurements with presently available liquid scintillation counters. A set of 3H samples which have activities ranging from 10(4) to 10(7) dpm were prepared and measured repeatedly in every possible different order with six counters of different models. The results demonstrate that the measured counting rates of the samples are subjected to much greater variations than expected from counting statistics. The poor reproducibility was found to be attributed to rate dependent photomultiplier gain variations. The variations in counting rate as large as 10 per cent was observed in a particular counter. It is also found that rate dependent photomultiplier gain variations can cause the external channel ratio to shift, giving rise to error as large as 9% in the efficiency determination.

[Evaluation of the reproducibility in radioactivity measurements with liquid scintillation counters--effect of anomalous count rate-dependent photomultiplier gain variations (author's transl)]

Time variations in count rate were measured for prolonged period of time using a set of 3H samples and a few other specially prepared samples of 14C, 32P, and 137Cs. Besides, beta-ray spectra of a particular 3H sample were measured as a function of time with a multichannel pulse height analyzer. These measurements lead to the following conclusions: (1) Anomalous count rate variations are attributed to strong dependence of photomultiplier gain on count rate. (2) Different steady state count rates can be observed for 3H samples having activities of approximately 10(5) dps when they are measured immediately after the measurements of background and 3H samples of higher activities. (3) The count rate-dependent effect on photomultiplier gain can be described properly by the current flowing through the tube rather than the count rate. (4) The measurement of the external standard channel ratio using the built-in 137Cs source can affect seriously the successive measurements on 3H samples, while the channels ratio itself exhibits strong time dependence.

Reserve capacity of bicarbonate secretion in chronic pancreatitis

When secretin was given by continuous intravenous infusion in the control subjects, the dose of secretin inducing maximal bicarbonate output was found to be around 6.0 CHR U/kg/hr. Then the pancreatic exocrine secretory response to sequential standard (1.2 CHR U/kg/hr) and augmented (6.0 CHR U/kg/hr) dose of secretin was studied in the controls, in patients with chronic pancreatitis and in its suspected cases. This new method for exocrine pancreatic function did not offer advantage for the diagnosis of well established chronic pancreatitis. But from the results obtained in suspected chronic pancreatitis it was supposed that the decline of increasing rate of bicarbonate output with augmentation of dose and the decrease of response to augmented dose of secretin might be one of functional disorders occurred in the early stage of chronic pancreatitis.

Secretin-like bioactivity in the duodenal mucosa in patients with peptic ulcer and chronic pancreatitis

Biopsy specimens of the duodenal mucosa were assayed to determine their secretin-like activity in 9 controls, 9 patients with gastric ulcer, 19 patients with duodenal ulcer, 4 patients with gastric and duodenal ulcer, and 13 patients with chronic pancreatitis. The bioassay of secretin was done on the pancreatic secretion in anesthetized rats. The sensitivity was in the orcer of 0.0625 CHR unit/rat (4 ng/rat). In the range between 0.0625 and 0.5 CHR units a satisfactory dose dependency was recognized. The following results were obtained. 1) The level of duodenal mucosal secretin-like activity in patients with gastric ulcer was the same as that in the controls, but was elevated in 32% of the patients with duodenal ulcer, 50% of those with gastric and duodenal ulcer, and 8% of those with chronic pancreatitis. 2) The high level of secretin-like activity noted in patients with duodenal ulcer was suspected to be related to the hypersecretion of gastric acid which is characteristic of this disease, but there was no correlation between gastric acid secretion and secretin-like activity in the duodenal mucosa.

Bioassay of cholecystokinin in the duodenal mucosa

Cholecystokinin (CCK)-like activities in the duodenal mucosa were measured by bioassay in patients with duodenal ulcer, cholelithiasis and some other gastrointestinal diseases as well as in healthy normal subjects. The mean CCK-like activity of the duodenal mucosa in patients with duodenal ulcer and cholelithiasis was 0.405 Ivy dog units per milligram and 0.376 Ivy dog units per milligram of dry weight of the duodenal mucosa (IDU/mg d.w.), respectively. Both these figures are significantly higher than 0.180 IDU/mg d.w. in normal subjects (p less than 0.005, p less than 0.005, respectively). It can be speculated that the CCK-level of the duodenal mucosa in patients with cholelithiasis may be regulated by a feedback mechanism and CCK in patients with duodenal ulcer may act physiologically for the cure of duodenal ulcer.

Electronmicroscopic identification of type C particles in cultured murine neuroblastoma

Monolayer of murine neuroblastoma were treated with dexamethasone and examined by electronmicroscopy. Most of the treated cells were morphologically differentiated and exhibited type C virus particles which were budding from the cell surface. This in vitro system may be of great value for exploring the oncogenic potential of the virus, and its possible role in cell differentiation.

Morphological differentiation of a murine neuroblastoma clone in monolayer culture induced by dexamethasone

Dexamethasone induces morphological differentiation in murine neuroblastoma cells in culture. The percentage of differentiated cells depends on the concentration of dexamethasone in the medium and duration of treatment. After drug removal (with or without replating), many cells maintain their differentiated phenotype. Dexamethasone-treated cells have larger soma and contain more protein. Dexamethasone also produces a concentration-dependent inhibition of population growth. Growth inhibition is complete by 2 days following treatment with dexamethasone 50 micrograms/ml. Complete growth inhibition is achieved prior to the complete expression of morphological differentiation. Androstenedione, testosterone, and 17-beta-estradiol--all steroids without glucocorticoid activity--have no differentiating effect, although they inhibit growth or cause cell death at higher concentrations.

Fine structure of the epidermis of the optic tentacle in a slug, Limax flavus L

The epidermis at the tip of the optic tentacle in Limax flavus is constructed of columnar epithelial cells, distal processes of nerve cells, and scattered processes of the collar cells. The epithelial cells extend stout microvilli called plasmatic processes by Wright perpendicularly from the free surface. Each plasmic process branches into a few terminal twigs embedded in a fuzzy filamentous substance. Most nerve cells have their nuclei under the basal lamina. The distal processes of these nerve cells reach the free surface and send long microvilli to form the spongy layer under a filamentous covering. At the side surface of the tentacle the epithelial cells are cuboidal or squamous and the neural elements are fewer. Here, no spongy layer is formed; and the collar cell processes are replaced by the lateral cell processes. Peculiar secretion granules are contained in the lateral and collar cell processes as well as in their cell bodies situated beneath the basal lamina.