Study Of Pancreatic Secretion Research Articles

Early concepts of nutrition, digestion, diseases of the gastrointestinal tract and their treatment: from Hippocrates and Galen to Maimonides

For over a thousand years, Hippocrates and Galen have been the Alpha and Omega of medical knowledge. Despite the importance of their contributions to clinical and theoretical medicine, they lacked a true understanding of anatomy and physiology. Hippocrates is commonly associated with proposing the doctrine of «tissue fluids», or humoral pathology, and his book, «On the Nature of Man», promotes this point of view. Galen became inherited the knowledge of Hippocrates. Ultimately, he was recognized as one of the most influential physicians of all time. The number of his works was enormous: he wrote more than a hundred books, which were widely distributed. One of Galen’s main commandments was the rule of harmony: all body systems are balanced; disease is a result of an imbalance. As one might expect, some of his ideas, however, were erroneous.
 Aristotle considered the pancreas, due to its location in the abdominal cavity, as an organ which only task was to protect the adjacent vessels.
 In an era when unknown diseases wreaked havoc, the concept of known causes of diseases led to the fascination with the study of food poisons and their antidotes. This was common among aristocracy who felt particularly vulnerable to this kind of threats. According to legend, one of the most famous connoisseurs of poisons was Mithridates VI.
 Pedanius Dioscorides was a Greek who served in the Roman army during the reign of the emperor Nero. The wandering nature of life led him to study a large number of diseases and medicines. The catalogue of his medicinal herbs and plants became the basis for the study and understanding of the medicinal properties of plants.
 Liver was considered the source of divine prophecy in many ancient cultures. The anatomy of liver was well known in ancient Babylon: a huge number of clay tablets and objects were left, which testify to the importance of «hepatoscopy» in the Middle East as a form of prediction. Those who used the insides of animals for divination (e.g., haruspices — divine interpreters of the future, using the liver as a prediction tool), could be considered the first official anatomists, since the understanding of the future depended on accurate knowledge and interpretation of certain liver components.
 After the victory of the Assyrian king Sargon over the forces of Urartu and Zikirti in 718 BC, Sargon wanted to appease the gods by sacrificing animals; in doing so, he studied their livers for predictions.
 Although the concept of pancreas is rooted in ancient times, as evidenced by the comments of haruspices and priests, knowledge of the organ functions eluded humanity until the works by Danish physiologists Francis Sylvius and Regnier de Graaf. Prior to their studies of pancreatic secretion and the elucidation of the role of pancreas in digestion, described by van Helmont and Albrecht von Haller, most researchers focused on the anatomical description of the organ. If the ancient Assyrians and Mesopotamians did not believe that liver predicts the future, but believed that it was pancreas that did it, then pancreatology may have earlier origins.
 Maimonides, a Jewish scholar and humanist, was also influential in other fields: he condemned astrology and its attempts to calculate the time of the Messiah’s coming. In the field of medicine, he paid attention to prevention, and was interested in the treatment of diseases of the gastrointestinal tract.
 By the beginning of our era, ideas about digestion, diseases of the digestive tract and their treatment remained very vague. There was a long and difficult way ahead in this area.

Study of pancreatic secretion after subtotal gastrectomy followed by different methods of reconstruction.

To study the effect subtotal gastrectomies have on exocrine pancreatic function, 12 dogs were prepared with gastric and duodenal cannulas using a modified technique of Thomas. In our study protocol, we collected pancreatic juice by selective ductal cannulation after having applied two types of stimulation [tryptophan intraduodenally together with secretin intravenously (i.v.) and cholecystokinin i.v. together with secretin i.v.]. Our results did not show a significant increase in pancreatic juice after performing the gastrectomies. In both cases the concentration of bicarbonate decreased significantly in contrast to that in the control group. After Billroth I anastomosis, however, a significant decrease in the first periods of stimulation in relation to the gastrojejunostomy was appreciated. In the case of proteins, a loss of the dose/effect relation in these parameters was seen only after Billroth II anastomosis.

Cerulein-induced acute pancreatitis in the rat. Study of pancreatic secretion and plasma VIP and secretin levels.

A study was made with different doses of cerulein (2, 4, 10 and 20 micrograms/kg) administered subcutaneously to rats by four injections at intervals of 1 hr; the aim of this work was to study exocrine pancreatic secretion of the rat under cerulein-induced acute pancreatitis, analyzing enzyme and hydroelectrolyte secretion of pancreatic juice. A further aim was to study the relationship between the dose of cerulein and the plasma levels of peptides controlling hydroelectrolyte secretion of the pancreas, like secretin and vasoactive intestinal peptide (VIP). At the lowest dose schedule, the amounts of total protein and enzymes (amylase and trypsin) in pancreatic juice decreased significantly, plasma amylase increased, and the pancreas became edematous. Higher doses magnified these effects. By contrast, ductular function (flow and HCO3-) was well preserved in cerulein-treated rats, and this was probably due to the significant increase in plasma levels of immunoreactive secretin whereas VIP levels were unchanged. The secretin released by treatment with cerulein is able to palliate the lack of flow from acinar origin that is affected in the process of acute pancreatitis, being a beneficial response to the cerulein treatment.

Gastro-intestinal and biliary biopotentials following various forms of vagotomy.

By means of an original method, the electrical activity of different regions of the digestive tract is determined in dogs, following various types of vagotomies. The recordings were performed in basic conditions and after pharmacodynamic stimulation with acetylcholine, atropine and adrenaline. The researches were completed by biochemical studies of gallbladder bile (dry residues, content in biliary pigments and cholesterol), y by enzymatic studies of pancreatic secretion, stimulated with physostigmine (amylase, trypsin and lipase) and by following the intestinal bacterian germs. The obtained data attest, that only bilateral selective vagotomies reduce to a minimum the postoperative disturbances occurring after total vagotomies (biliary and pancreatic troubles, and intestinal dysbactery). The advantages of using the selective vagotomies as an election method in surgical treatment of the duodenal ulcer disease are thus substantiated.

Continuous Pancreatic Secretion.

The following study was undertaken in order to determine the characteristics of the flow of pancreatic juice in the fasting dog and the influence of certain stimuli upon the rate of pancreatic secretion. Cl. Bernard1 and Pavlov2 believed that pancreatic juice was secreted intermittently in response to specific stimuli. Continuous secretion was regarded by them as an abnormal response of the pancreas to irritation and inflammation. Farrell and Ivy3 found that pancreatic transplants secreted continuously in dogs. Recently Baxter4 reported that spontaneous pancreatic secretion occurred in rabbits under prolonged urethane anesthesia, after decerebration or decapitation, and after extirpation of the entire gastro-intestinal tract.Permanent pancreatic fistulas were established in 4 dogs under ether anesthesia and with strict asepsis according to the technic described by Elman and McCaughan.5 This method permitted a study of pancreatic secretion under relatively normal conditions. The pancreatic juice remained u...