[Physiological mechanisms for maintaining the body's energy requirements during reduced blood hemoglobin levels]. / O fiziologicheskikh mekhanizmakh obespecheniia énergeticheskikh potrebnostei organizma pri umen'shenii kontsentratsii gemoglobina v krovi.

Energy expenditure and O2 consumption, the tidal volume of cardiac output (Q) and the respiration (VE), the arterio-venous difference in O2 content, the arterial and venous blood gases, and the survival of animals in graded decrease of the hemoglobin concentration in the vascular bed (hemodilution) were studied in anesthetized Wistar rats as well as the values of oxygen available in the brain tissue. The animals were shown to maintain the initial level of energy expenditure by means of the Q increase up to reducing the hemoglobin concentration from 16.2 g/dl to 4.9 g/dl (hematocrit 12.9%). The elements of oxygen insufficiency, however, as measured by the Q and VE responses as well as by changes in oxygen available in mixed venous blood and in brain tissue, become evident yet in early stages of the hemodilution.

[Antigenic properties of the proteolytic enzymes of the gastrointestinal tract]. / Antigennye svoistva proteoliticheskikh fermentov zheludochno-kishechnogo trakta

Antigenic properties of crystalline pepsin, trypsin and chymotrypsin were studied in 9 rabbits immunised with these enzymes. Production of antibodies and their titres were investigated by means of the reaction of the precipitation in testing tubes and immunoelectrophoresis. The most clear antigenic properties were revealed in trypsin, and they were the weakest in pepsin. Low titres of the antibody to pepsin were, probably, due to denaturation of its molecule at physiological values of pH immunisation. Absence of cross-reactions of antisera to trypsin and chymotrypsin with pepsin solutions may be due to considerable structural differences of the antigenic determinants of pepsin from those of trypsin and chemotrypsin. However, antisera to trypsin and chemotrypsin do develop cross-reactions with respective enzymes and there were may be due to a similarity between structures of their antigenic determinants.

[Participation of the stomach and small intestine in the mechanism of insulin secretion following oral glucose administration]. / Uchastie zheludka i tonkoi kishki v mekhanizme sekretsii insulina posle peroral'nogo vvedeniia gliukozy

In chronic experiments on 22 dogs, four of them having fistulas of oesophagus, stomach, and duodenum combined with artificial dissociation of stomach from duodenum, the per os and intraduodenal administration of glucose increased concentration of glucose and immunoreactive insulin in the peripheral blood, while intrastomach administration of glucose increased the immunoreactive insulin concentration alone. The data obtained suggest three phases of insulin mobilization: the first is due to neural mechanisms and occurs at the moment of contact between glucose and mucosa of the mouth, stomach, and duodenum; the second phase seems to be due to enterohormones and is activated by the contact between glucose and mucosa of the mouth, stomach, and duodenum; the third phase is associated with resorptive hyperglycemia which directly activates the B-cells.

[Secretion of proteolytic enzymes following administration of nutrients into the duodenum and jejunum]. / Sekretsiia proteoliticheskikh fermentov pri vvedenii pitatel'nykh veshchestv v dvenadtsatiperstnuiu i toshchuiu kishki

Infusion of nutrient fluids into the small intestine of dogs provoked the appearance of Pavlov's pouch juice displaying different proteolytic activity. The quantity of the juice was smaller with drop than with jet infusion. The total secretion of enzymes was more abundant in case of drip intraduodenal infusions of a milk and cream mixture, milk, aminocrovine as compared with its average level following introduction of 10 and 20 per cent solutions of sugar, lipomaize, emulsions prepared of dry dairy products and vegetable oil. The infusions into the duodenum and jejunum was followed by secretion of substantial amounts of the pancreatic juice displaying high activity of trypsin, close to that appearing in response to feeding on meat. The concentration of proteases in the intestinal chyme proved then sufficiently high.