Frank C. Mann

An experimental study of the rhythmic contractions in the small intestine of the dog.

Exteriorized loops were prepared at various levels in the small bowel of trained dogs and the occurrence and rate of rhythmic contractions noted. Rhythmic contractions were found to be a relatively rare form of movement in these preparations, occurring in about 2 per cent of all tracings. The remaining 98 per cent of the tracings was occupied by irregular types of segmentation, peristaltic and tonus waves. The rate of rhythmic contractions was a constant for any given loop with a variation of plus or minus one contraction per minute. The rate of any given loop was found to be a function of its distance from the pylorus, the loop at the highest level having the highest rate, that at the lowest level having the lowest rate. The rate was not affected by fasting, feeding or sleep, except that in the recently fed animal, rhythmic contractions were less commonly observed than in the fasting animal. The rate was unaffected by degenerative vagal and splanchnic section.

Nitrogenous Constituents of Blood Following Transplantation of Ureters Into Different Levels of Intestine.

In an attempt to study the effect on the kidney of the presence of large amounts of normal urinary constituents in the blood, we transplanted the ureters into different portions of the intestine. A simplified surgical technic was employed and the results were for the most part satisfactory. In most instances the only demonstrable change in the ureter and kidney was slight dilatation of the ureter and pelvis of the kidney, while microscopic examination of the renal tissue revealed but minor changes. In some cases, however, hydroureter and hydronephrosis with subsequent pyonephrosis developed. These cases furnished an interesting comparison to uncomplicated ureteral transplantation. A single ureter was transplanted into the jejunum, ileum, colon, and rectum in different dogs. When the other kidney and ureter was not disturbed practically no change was observed in the nitrogenous constituents of the blood over a period of several weeks following operation. Bilateral transplantation of the ureters or single transplantation with removal of the kidney on the opposite side produced some very interesting changes in the constituents of the blood. Drainage of the ureters into the rectum produced in most instances a marked rise in the blood urea for from several days to six weeks after operation and a subsequent return of the level of urea in the blood to a figure which is within normal limits. No changes were found in the creatinine, creatine, uric acid, or ammo-acid content of the blood. Following ureteral transplantation into the colon there was a similar rise in the blood urea nitrogen without significant changes in the other nitrogenous blood constituents studied.

The gastro-ileac reflex: Further experimental observations

The activity of exteriorized loops of jejunum, ileum and colon in continuity in trained dogs was studied in relation to feeding.

The activity of the lower part of the lleum of the dog in relation to the ingestion of food

The activity of exteriorized loops of the lower part of the ileum in continuity, enclosed in bipedicled tubes of skin, was studied in the dog in relation to the ingestion of food. A regular cycle of activity was noted in the normal animal: namely, a rapid motor response to feeding, followed by prolonged activity which gradually diminished until, after forty-eight hours of fasting, the activity was extremely feeble.

The effects of whole bile and bile salts on the innervated and the denervated heart

Abstract The effects of the intravenous administration of whole bile and bile salts on the blood pressure and the electrocardiogram were studied in a series of acute experiments, under pentobarbital sodium (nembutal) anesthesia, on normal dogs and on dogs with denervated hearts; the same methods and technical procedures were employed in both cases. Similar observations were made over a period of several weeks on normal, trained dogs, and on one trained dog with a denervated heart; this permitted us to make repeated observations which could not have been influenced by anesthesia, operative trauma, or an accumulative effect of successive injections of bile. There were no detectable electrocardiographic differences between the effects of whole bile and bile salts on the innervated and the denervated heart; the irregularities and slowing of the rate of the heart were similar. During the period of gradual recovery from the hypotensive effect brought about by the first injections of bile constituents, the blood pressure of the dogs with denervated hearts usually did not return to its previous level, but the blood pressure of the dogs with innervated hearts, usually tended to do so. In both the normal animals and those with denervated hearts, approximately the same, gradual, hypotensive effect was produced by the intravenous administration of repeated doses of whole bile or bile salts. The injections finally led to failure of the heart, fall of blood pressure, and death of the animal. Our observations on the innervated heart differed so slightly from those on the denervated hearts of otherwise intact dogs to which whole bile or bile salts were administered intravenously, that it appears justifiable to conclude that whole bile and bile salts can produce practically the same hypotensive effect and cardiac changes, such as bradycardia and disturbances in rhythm, in the absence, as well as in the presence, of the cardiac autonomic nerves.

Prophylactic treatment of peptic ulcers produced experimentally by cinchophen

Some benefit was found from a diet of milk alone and from the use of a duodenal extract in the prophylactic treatment of peptic ulcers produced experimentally by the administration of cinchophen. Mucin appeared to be definitely beneficial in some cases but in others a chronic ulcer developed similar to those found in control animals fed cinchophen without prophylactic treatment. A chronic lesion was not produced in the presence of alkali-milk diet therapy. No benefit was observed from intramuscular injections of histidine monohydrochloride.

The effects of whole bile and bile salts on the perfused heart

Abstract A series of experiments were performed on the isolated perfused heart of the rabbit. The changes in cardiac activity were observed, and graphic records were taken to portray the disturbances produced by whole bile and commercial preparations of sodium taurocholate and sodium glycocholate on the amplitude, rate, and rhythm of the contractions of the perfused heart. Definite and uniform effects were produced. Commercial preparations of bile salts and whole bile from the gall bladders of humans, dogs, and rabbits produced a slowing of the rate of the perfused heart, a diminution in the amplitude of its contractions, and a variety of irregularities in its rhythm, such as ventricular alternation, extrasystoles, and, finally, ventricular fibrillation, ending in complete cardiac failure.

Studies on peripheral blood flow

Abstract Since the beginning of our work on blood flow in animals about ten years ago, we have investigated many problems concerning the peripheral circulation of the dog. In this report a number of studies have been summarized, and, in some instances, additional data only recently obtained have been included. These studies will serve to illustrate the dynamic nature of the peripheral circulation, as reflected in the blood flow in the femoral artery or vein.

Role of the small intestine during emesis

Intestinal activity precedes the act of vomiting when studied in exteriorized loops (7). It is suggested tentatively that this activity is antiperistaltic.

Effect of liquid and solid meals on intestinal activity

The activity of exteriorized but otherwise intact loops of jejunum or ileum was studied in a group of trained dogs. After a fasting period of forty-eight hours the loops were usually quiet but frequently showed periods of slight activity. The introduction of a stomach tube in sham feeding, the introduction of water or various liquid meals, and the feeding of a solid cooked meat meal caused a typical motor response, a sudden burst of marked activity. This response was maintained, however, only in the case of the solid meal. It disappeared within a few minutes in sham feeding. When water or various liquid meals were introduced the motor response diminished rapidly; activity of low grade, irregular, segmentation waves and inconspicuous tonus changes were maintained for about a half hour in the case of water, and for about an hour in the case of liquid meals. Rhythmic movement was noted most frequently when the bowel was quiet, usually immediately after an episode of slight activity. When the solid meal was given the motor response was sustained for hours, the activity being marked by prominent irregular segmentation waves, tonus changes and tonus waves, and occasional peristaltic waves. Twenty-four hours after the solid meal the small intestine usually showed moderate or slight activity. A fasting period of three or four days often resulted in unpredictable and atypical periods of activity, both before and after the feeding of liquids.