Complete Text (Part 9)

acids are present, the combined acids may be part HCl and part organic, or all organic. AVhere delicate discrimination is needed and it is necessary to know if any HCl is excreted by the gastric glands, the folloAving method should be adopted: 3. Incineration with BaCOg. If any HCl is present it will combine with BaCOo and form the soluble BaCls- The addition of HgSO^ will precipitate insoluble BaSO^. The appearance of a precipitate after this procedure signifies the presence of HCl. Filtration, incineration, weigh- ing and calculation will give amount of HCl. IV. Organic Acids. Practically all foods contain some fatty acids. Where rancid butter, vinegar, sour milk, etc., are included in the diet, the amount may be consider- able. Carbohydrates, contained in milk, bread, meat, etc., always contain some lactic acid, and the find- ing of an excess amount in the gastric contents after the ingestion of such foods points to a fermentative process at wqx% in the stomach, due possibly to a combination of decreased HCl and decreased motil- ity. Boas thinks that with a normal diet there should be no appreciable formation of organic acids in the stomach during normal digestion. Bacterial decomposition, in the absence of HCl, plan's an im- portant source of their production. The presence of a fat-splitting ferment would also produce them. In fermentation processes lactic acid, but^^ric acid and acetic acid are generalh' found. Lactic acid is used as an index of organic acid production, be- cause (1) it is produced in greater amounts than 113 the others and is thus more easily detected; (2) qualitative tests for it are quick and simple. Quantitative tests for organic acids are not used clinically. Xo clinical information is obtained by quantitative data because there exists no correlation between the amount of organic acid present and the severity of the lesion. A. Qualitative consideration of lactic acid. With the Ewald meal in normal digestion, as a rule, no lactic acid is found in the gastric contents ; but there is a slight abnormality, even within nor- mal limits, in which it may be found. In such bor- derline cases the use of the Boas meal is advisable. Normally the small amount of lactic acid in the EAvald meal is either (1) absorbed or (2) cannot be detected on account of the presence of the normal amount of HCl, which interferes with its tests. Pathologically, lactic acid appears in conditions of stagnation and low HCl output. Such conditions are, found in (1) carcinoma, with obstructive fea- tures ; (2 ) hypochlorhydria or achlorhydria, . with sluggish motility ; (3 ) benign stenosis, with low HCl output. .^ - - :. . . . ; Tests for lactic acid : ■ " .' .....,• .■ ■•• ■ 1^ Uffelman's. -■ - :.: ;. _ Reagent: 1% phenol, 20 cc; dil. ferric chloride,.! drop; dist. water q.s. to mal^e a delicate . amethyst' color. . . Procedure : Divide amount of reagent between two test tubes, and into one add 5 — 8 drops of clear gas- tric juice (filtered, if necessary), and into the other add 5 — 8 drops of distilled water for a control. A positive test is indicated by the formation of a canary yellow color in the tube containing the gas- tric juice. If the reagent is not sufficiently diluted and is of too dark a color, a small amount of lactic acid will not give the characteristic lemon color, but 114 Avill simply decrease the intensity of the purple color. Sources of error: 1, yellow gastric juice; 2, acid sodium phosphate: 3, cane sugar; 4, glucose; 5, alcohol: 6, other organic acids. Modification : If doubt exists, make an ether ex- tract of the gastric juice, evaporate, take up the residue in distilled water and apply the test. 2. Kelling modification of UJielmann's test. Reagent: Distilled water, 20 cc. : 10% ferric chlo- ride, 1 or 2 drops. Procedure: Divide between two test tubes. Into one put a few drops of clear gastric, juice, and into the other a fcAv drops of distilled water for a control. A j)ositive test, as before, is the formation of a canary yellow color. Sources of error : Same as for Uffelmann's, except that acetic acid will not give yellow color. 3. Strauss test. This is the best clinical test, for it detects lactic acid when in pathological amounts. Procedure : Into a Strauss funnel put 5 cc. of gas- tric juice and a drop of HCl to free any organically- bound lactic acid. Upon this pour 20 cc. of alcohol- free ether. Invert several times, avoiding the forma- tion of an emulsion. Allow the gastric juice to es- cape through the stop-cock below and replace it with an equal quantity of distilled water. Shake several times in order that the lactic acid extracted with the ether can be taken up by the water and add a few drops of a 10% solution of ferric chloride. An intense green color will appear if more than .1% lactic acid is present, paler shades of green if less is present. B. Qualitative consideration of butyric acid. Physiologically, none is present in the stomach during digestion unless (1) hea^^^ carbohydrate meal has been taken, (2) it is taken directly in the 115 form of rancid butter, etc., (3) it finds it way into the gastric juice from the mouth. Fugge has shown that it may be formed from lactic acid. Method of detection : 1. Odor specific. 2. Shake material with ether, evaporate ether ex- tract, take up with water and a small amount of CaCU, and upon Avarming butyric acid w^ill settle out, recognized by (1) droplets, (2) odor of rancid butter. C. Qualitative consideration of acetic acid. Acetic acid is frequently found in large amounts when taken in the form of vinegar. Pathologically, it is found in conditions of stasis with yeasts and fungi. The stomach in this condition is usually dilated and atonic. Yeast action on carbohydrates yields alcohol, which, in turn, when acted upon by yeasts and bacteria, yields acetic acid. Method of detection : Shake the material with ether and extract with water. Neutralize with NaCOo, carefully. Acid prevents the necessary re- action and alkali causes formation of ferric hydrox- ide when ferric chloride is added. Add a few drops of ferric chloride and look for appearance of deep ved color. Upon boiling a reddish precipitate of basic ferric acetate will also form when acetic 'acid is present. D. Detection of blood. The guiac and benzidine tests are carried out in the same manner as for similar tests in the urine. II. Consideration op Ferments. A. Pepsin is the chief ferment and is secreted by the peptic glands. B. Lipase, which is slight in amount and of ques- tionable origin.. Possible origin: 116 1. Regurgitated duodenal contents, pancreatic origin. 2. Derived from secretion of Brunner's glands in intestine. 3. Dual origin from both. C. Diastase, a small amount of Avliich is of gas- tric origin, but the greater amount of which is due to swallowed saliva. A. Pepsin. This ferment is secreted as propepsin, is activated by HCl, and destroyed by alkali. Other acids will activate it, but in higher concentration, viz: HCl, .2— .4%, lactic 1—1 plus ?c: The action of pepsin is continuous, and a great amount of work is accomplished by a small amount of pepsin, pro- vided that the products of its digestion are removed. Stasis hinders its action. Decrease in amount of pepsin. Due to disease of peptic glands. Pepsin is generally present when the HCl is high, low or even absent. Pepsin may be absent in the following conditions : 1 . Carcinoma, especially the liniis plastica type. 2.~ Atrophic gas- tritis. 3. Occasionally in pernicious anaemia. The output of pepsin lias no relation to the amount of HCl present. . ' . . ' - ■' Qualitative tests jor pepsin: --■"'.'.:■. These are- based upon the digestion of protMii-in- the form Of il. Fibrrn, which is obtained by whip- ping ox blood and is then washed, kept in alcohol for two or three days, then carmine for two or three days, and finally preserved in glycerin till used. 2. Albumin, which is made by cutting the whites of hard-boiled eggs into small squares and preserved in glycerin. Procedure : 1 . Into 25 cc. of gastric juice with free HCl place either a number of pieces of fibrin or albumin j^repared as above. Incubate for 15 min- utes to an hour. The fibrin swells up in 15 to 30 117 minutes and liberates the carmine. It is all gone normally in 1 to IV2 hours. The albumin swells up in 30 to 60 minutes and is well gone in three hours. Quantitative tests for pepsin. 1. Hammerschlag's. 1% solution of egg albumin in 0.4% HCl {egg albumin 1 part, 0.4% HCl 13 parts j 10 cc. Gastric juice 5 cc. Incubate at 37 deg. for one hour and run a con- trol tube with 5 cc. of distilled water instead of gastric juice. At the end of an hour run an Esbach determination on both the tubes, also on the original 1% solution. Xormallv 90% of the albumin is digested in the hour. Sources of error: Albuminoses are thrown down with albumin. 2. Mett's method. (The one of choice.) Preparation of tubes : Take several whites of eggs, cut them, filter through gauze and use the liquid portion to fill capillary tubes 10 to 30 cm. long by 1 to 2 mm. bore. Fill tubes by suction, seal with bread crumbs, drop into boiling water (95 to 100 (leg.) for 5 minutes, and then seal ends with paraffin to prevent drying. AVhen read}" to use cut tubes into 2 cm. lengths. Sources of error to be avoided in preparation of gastric juice: 1. If too concentrated, especially after meals, there may be present substances which inhabit di- gestion, i. e., XaCl and carbohj'drates in solution. 2. Schultz's law holds with digestion up to 3.6 mm. The length of the cylinder of albumin digested by any gastric juice is proportional to the duration of digestion and is independent of the diameter of the capillary tube, provided that the length of the ii3 digested column does not exceed 7 mm. For this reason the gastric juice is diluted. 8. Kesult of peptic digestion hinders further di- gestion. 4. Pepsin is activated by HCl and its presence is essential. Procedure: Into a small dish place Filtered gastric juice 1 cc. .18% HCl 16 cc. 2 cm. Mett's tubes 2 Incubate 24 hours. Kead four ends, take aver- age and square. Note: It is often desirable to set up two addi- tional dilutions of gastric juice, using 32 cc. and 64 cc. of .18% HCl to 1 cc. of gastric juice. Unit of digestion equals the amount of pepsin necessary to digest 1 mm. length of albumin in 24 hours in the presence of .18% HCl. Calculation. This is based upon Schultz's law, which may be stated as follows : Relative amounts of pepsin, in constant acid solutions and time of action, are proportional to the square of the length of the column of digested albumin, or the square of the length of the digested cylinder of albumin is proportional to the pepsin concentration, pro- vided the length of the digested column is less than 3.6 mm. Example : Average length 3 mm. 3- X 16 (dilution) = 144 units. Significance: 0 to 70 units — low. 70 to 150 units — average. 150 to 250 units— high. B. Rennin (chymosin). Pepsin and rennin run parallel in most cases, but marked variations may occur. One or the other may be suppressed or follow different curves of secretion. Some have tried to show that pepsin 5 cc. 10 cc. Coagulation shows the 119 and rennin are identical, but this is probably not true, for there are some differences between these two ferments, viz: pepsin acts onh^ in acid media, while rennin acts in acid, neutral, or slightly alka- line media. Its action is to make insoluble casein from caseinogen. Qualitative test for rennin: Neutral gastric juice Fresh milk 5 to Incubate for 15 minutes presence of rennin. Quantitative test (Boas). In a rack place 6 test tubes. In the first tube place 1 cc. of gastric juice and 9 cc. of distilled vv^ater, which gives a dilution of 1 to 10. Into the remaining tubes place 5 cc. of distilled water. With a 5 cc. pipette mix the contents of the first tube by drawing the solution up and down three or four times, then transfer 5 cc. of it to the second tube, mix as before, transfer 5 cc. from the second to the third tube and so on till the last tube, when 5 cc. are discarded after mixing. The dilutions are as follows : 1. 1—10. 2. 1—20. 3. 1—10. 4. 1—80. • 5. 1—160. 6. 1—320. After these dilutions have been made add to each tube 5 cc. of fresh or, preferably, boiled milk, and 21/2 cc. of 1% CaC12. '^ ' Place in a thermostat for 30 minutes and read. In abnormal conditions the coagulation is low, if only in the first tube, interference due probably to acid salts. Normally, there should be coagulation up to 1—160. C. Lipase. This ferment does action is very slight. occasionally occur, but its Gastric digestion is not con- 120 cerned with the splitting of fats. In testing for this ferment be snre to nse a fat-free meal. Qualitative test for lipase : 1. Wash stomach out thoroughly. 2. Give fat-free test meal. Kemove. 8. Incubate, adding some neutral butter. Positive results show presence of fatty acids. Examination of the duodenal contents for fer- ments. Method of obtaining duodenal contents : Give pt. 200 c. of olive oil by mouth. Half hour later pass stomach tube and obtain regurgitated duodenal contents. Set up for examination of duodenal contents for ferments. 50 ^ Q O 9 W ^ > 9p to CD ^2. ahlbaum solution 1% in t ^2 w c-t- a> S3 5' 1- W2. i-5- ^^ p I . . . . . 2 cc 0 2 cc 2 cc 2 cc II . 1 cc 1 cc 2 cc 2 cc 2 cc III . 0.7 cc 1.3 cc 2 cc 2 cc 2 cc IV , 0.4 cc 1.6 cc 2 cc 2 cc 2 cc V . 0.2 cc 1.8 cc 2 cc 2 cc 2 cc VI . , . 0.1 cc 1.9 cc 2 cc 2 cc 2 cc VII . 0.0 cc Control 2.0 cc 2 cc 2 cc 2 cc Incubate tubes at 38 deg. C for 30 min. in water bath, cool rapidly and read at once. Titrate tubes A with a saturated solution of NaCl, which gives white ppt. Add Lugal's solution to tubes B and obtain blue color if starch is pres- ent. Titrate tube C with N/10 XaOH, using phenol- phthalein as indicator. Method of preparing casein solution: X/10 XaCl 5 cc. Casein 0.1 gm. Dist. water 45 cc. 121 Boil, with constant watching and stirring, for from 3 to 5 minutes. Allow to cool, make neutral with HCl or N/10 NaOH ( phenolphthalein as in- dicator) and bring volume up to 100 cc. with dist. water. Method of preparing starch solution: Starch 1 gm. Dist. water 100 cc. Boil from 3 to 5 minutes, allow to cool, and make up volume to 100 cc. Method of preparing Monobutyrin solution: Monobut^^rin 1 cc. Dist. water 99 cc. Normally, tube No. VI. shows digestion of casein and starch. The lipase test is practically never done because of numerous sources of error and uncertain end point. In diastase test the last positive tube is the tube just before the one which shows blue, probably brownish, due to presence of erythrodextrin. Gastric digestion. A. Protein. Pepsin and HCl change albumin into acid albumin, then into albumoses (four in num- ber), then into peptones. Gastric digestion is not carried beyond the peptones or the slightly lower polypeptid stage. When lower products of digestion are found their presence is due to the action of other ferments, either intestinal or those excreted by malignant growths. B. Carbohydrates. Some inversion of sugar oc- curs in stomach, due to t]ie acid there present. By the action of the salivary ferment starch is changed into soluble starch, erythrodextrin, achrodextrin and, finall}', into maltose. Ptyalin does not act in the presence of free HCl, but its action is so rapid that from 50 to 75% of starch is converted into the 122 soluble forn:. If the HCl is kept low, starch diges- tion will continue much farther than when it is present in higher concentrations. C. Fat. Practically none is digested normally as lipase is present only in a trace. Motility. Disturbance in tliis function of the stomach is of more imj^ortance than its secretory disorders. Food can pass into the intestine and be digested there irrespectiye of gastric secretion. If motility is im- paired, howeyer, food stays and stagnates in the stomach, causing more or less disturbance. Motor disturbances : 1. ^'omiting, already cousidered, important be- cause of loss of food. 2. Hypermotility, in which condition food is rushed through, and often associated with hyperacidity. Consider spasm also in these conditions.) .']. Hypomotility, which is important and seri- ous. Results of motor disturbances: 1. Disorders of secretiou. :?. Disorders of digestion. 3. Disorders of absorption. Causes of stasis : 1. Cancer with obstruction, associated general]}' with hypochlorhydria, achlorhydria or achylia. 2. Fleer with obstruction, associated generally with hyperchlorhy dria . ?. Spasm, generally associated Ayith hyperchlo- rhydria. 4. Atony, witli or without hypersecretion. 5. I'tosis, which interferes Ayith mechanical passage of food. Study of Motility. 1. Xot by acid content. 123 2. Not bj the size of the stomach, for a large stomach may have normal motility.