Intraorganic blood vessels of the intestinal graft after its ortho- and heterotopic transplantation

In experiments, performed on 85 dogs of both sex ortho- and heterotopic total autotransplantation of the small intestine and extracorporal connection of the allogenic segments of the small intestine have been carried out. Certain dependency of morphological changes of the intraorganic blood bed on the operation model has been stated. Essential changes in the blood bed at the heterotopic autotransplantation depend on inadequate regional hemodynamics in the graft. Therefore, the heterotopic model should be considered less preferable than the orthotopic one. One of the peculiarities in reconstruction of the intraorganic vascular bed after ortho- and heterotropic transplantation of the small intestine is, evidently, opening of lympho-venular anastomoses.     

Blood vessels and nerve apparatus of the heart and small intestine during continuous experimental bypass shunting]

In 140 animals (mongrel dogs of different age and sex) by means of histological, neurohistological, histochemical, histoenzymatic and electron microscopic methods, character and dynamics in changes of nerve elements and blood vessels of the heart and the small intestine have been studied under the conditions of revascularization at aorto-coronary and aorto-mesenteric shunting. The changes revealed are mainly reactive in their character, perform defensive, compensatory-adaptive response of the organs to the orative trauma and to an adequate but slightly changed blood stream. The degree of acuteness and the time when these changes disappear depends on duration of postocclusive ischemia, on the organs' resistivity to its effect on the operative trauma. Operation of aorto-coronary and aorto-mesenteric shunting are rather effective and protect the vascular bed and the intramural nerve appratuses of the heart and the small intestine from severe destructive disorders developing as a result of occlusion in the arterial vessels.     

Effect of structures of the ventral surface of the medulla oblongata on coupled vascular functions of the small intestine

The effect of the ventrolateral medulla electrical stimulation of various intensity on resistance, capacitance and exchange functions was studied in the vascular bed of the small intestine. Brain activation with superliminal current applied to a point 2 mm rostral-wise of the middle of the twelfth cranial nerve rootlets has been shown to produce the strongest effect on the precapillary resistance of the vascular bed, whereas brain stimulation in a point 2 mm caudal-wise of this level produces a much stronger effect on the postcapillary small intestine resistance.     

Structural changes in the small intestine wall and its lymphatic bed after gastrectomy

Morphologically and histochemically structural changes of the small intestine wall and its lymphatic bed have been studied in 104 dogs after the stomach resection. After the operation an increase in the diameter of the lymphatic capillaries and vessels takes place. Lateral dilatations and protrusions in the capillary walls appear, new anastomoses in all the membranes are formed, they are mostly manifested in the mucous membrane. Histopathological rearrangement in the small intestine wall is demonstrated as edema of the mucous membrane, as plethora of the vessels, as lymphoid infiltration and as changes of the villi forms.     

Lymphatic bed of the muscular sheath of the small intestine in animals and man during ontogenesis]

In the anatomy of the lymphatic bed of the small intestine muscle layer still there are obscure questions on the phylo- and ontogenesis of man and animals. Under study were 92 corpses (35 men, 27 cats and 30 dogs) of different age, beginning from the intrauterine period to old age. Different methods were used: polychromatic injection; macro- and microscopic dissection; staining after van Gieson and with haematoxilineeosin; impregnation with 0,25-1% solution of silver nitrate; dehydration and clearing; counting of the density of loops per a mm2 and the depth of their disposition in the intestinal wall with an ocular-micrometer. It was shown that formation of the lymph capillaries and their network in cats, dogs and man began from the end of the intrauterine period, was completed in new-borns and became sufficiently developed in young age. The structure of the lymph capillary networks is closely connected with the development of the muscle layer of the small intestine. Formation of the lymph lacunas begins after birth. With age the lymph capillary network becomes looser, the loops break and their size enlarges.     

小鼠小肠四种消化酶活力的胎后发育模式

为明确晚成型小鼠胎后发育肠道消化酶活力的建立过程和发育模式,探讨其与适应性调节假说的关系,测定了从出生后至27日龄小鼠小肠前、中、后段的乳糖酶、蔗糖酶、麦芽糖酶和氨基肽酶的酶活力。结果发现单位组织酶活力方面,乳糖酶活力先增后降,小肠前段在9日龄而中后段在12日龄达到最高,至27日龄时仅中段有微弱的酶活力;蔗糖酶活力12日龄始出现,前段和后段自15日龄迅速升高,至18日龄达最高,但随后显著降低,而中段在15日龄后持续升高至21日龄达到最高,此后维持在较高水平;麦芽糖酶出生时已具有活力,但在15日龄前维持较低水平,此后迅速升高,前后段在18日龄,中段在21日龄达到峰值,此后下降;小肠前段的氨基肽酶活力出生后至27日龄持续下降,而后段和中段从出生到断乳前则持续升高,断乳后略有下降。除乳糖酶总酶活力先增后降,在15日龄达峰值外,其余3种酶的总酶活力均持续增加。在小肠不同位置4种酶活力的分布具有显著差异,且日龄对不同位置酶活力的影响趋势不同。总之,小鼠小肠4种消化酶的酶活力随时间的变化能够与其食物转变的消化需求相匹配,部分地支持适应性调节假说。     

Formation of primary microvessels in the early stages of prenatal human morphogenesis

By means of light and electron microscopy, the most general mechanisms of formation and development of primary blood microvessels in functionally different organs (adenohypophysis, thyroid, thymus, liver, spleen, small and large intestine) have been studied in human embryos 4-8 weeks of age. Ultrastructure of cells in the extra- and intraorganic mesenchyme is described; to the latter belongs the leading role in organization the pathways of the prevascular microcirculation. The primary microvessels are formed as a result of canalization of the intercellular clefts, lining with mesenchymal cells, that gradually transfer into primordial endotheliocytes. Basing on ultrastructural analysis, certain stages of differentiation of protocapillary endotheliocytes have been defined and described in different organs. The change of the prevascular microcirculation into the intraorganic protocapillary bed (the primary blood bed) is an essential and necessary stage of the organogenesis.     

Age and the extent and topography of solitary lymphoid nodules in the wall of the human small and large intestine

Amount and topography of small lymphoid nodules (SLN) have been studied by means of the quantitative method in flat total preparations of the small and large intestine obtained from 111 corpses of persons of both sex (from newborn up to old age). Total amount of the SLN in the large intestine wall in all age periods exceeds that of the SLN in the small intestine wall. From birth up to the period of the 1 childhood total amount of the SLN increases successively, reaching (51 +/- 14) X 10(2) in the small and (74 +/- 11) X 10(2) in the large intestine at the age of 4-7 years. Beginning from 8 years of age up to old age, total amount of the SLN decreases successively, to a more degree in the wall of the small intestine than in the large intestine. The arrangement density of the SLN in the large intestine wall essentially exceeds that of the SLN in the small intestine wall during the all age periods. From birth up to early childhood the arrangement density of the SLN increases and then gradually decreases both in the small and large intestine. This demonstrates that development of the SLN takes place during the first 4-7 years of the human life, in contrast to the lymph nodes and tonsils, their greatest development takes place during juvenile and adolescent age.     

Anatomic transformation of the lymphatic bed of the small intestine following immunization]

The experimental investigation of the lymphatic bed of the small intestine after immunization was performed in 15 rabbits. Ten rabbits were taken as control. The rabbits were immunized by administration of kidney antigen with the complete Freund adjuvant. The animals were killed on the 7-8th days after two cycles of immunization, three injections in each cycle. The interval between the injections was three days, between the cycles - one month. Polychrome injection of arteries and veins was made. The lymphatic bed was filled with Gerota's mass. The chylus sinuses, lymph capillaries and vessels of experimental animals were found to be dilated 2-6 times as compared with normal. There appear many blind processes on the walls of lymph capillaries and vessels. Intraorganic lymphatic pathways were more dilated as compared with extraorganic. The ileum was found to be more reactive in immunization than other two parts of the small intestine.     

Systemic and organic changes in the microcirculatory bed in experimental dehydration of the body

Among systemic mechanisms of microvascular reactivity of the musculus spinotrapezius, pancreas and small intestine mesentery at dehydration, a special role play the changes directed to maintenance of harmony between the capacity of the blood bed and volume of the circulatory blood, morpho-functional factors on regulation of hemodynamics, as well as mechanism of liquor resource++ elimination from the blood bed. The organic peculiarities of the microvascular reactivity at dehydration are determined by topic and quantitative character of their changes.     

Morphofunctional transformations of the blood vessels in the transplantation of syngeneic normal tissue and of a tumor

In 360 Fisher rats dynamics of changes in blood vessels, the microcirculatory bed vessels included, have been investigated. An original model of the experiment at implantation of syngenic tissues of the fetus normal intestine and tumorous adenocarcinoma of the small intestine has been used. Specific changes of the blood vessels have been revealed around and in the capsule of the implant, depending on their morphological reorganization. The blood vessels changes can serve as a prognostic sign of possible alterations in the implant structure.     

Effects of thermal factors on the state of microcirculation of the small intestine in acute ischemia

The influence of normo- (38 degrees C), hyper- (42 degrees C) and hypothermia (20 degrees C) on microcirculatory disturbances caused by acute local ischemia of the small intestine was investigated with the help of biomicroscopy as well as morphological methods. Ischemia was modeled by ligation of the intestine look eventrated through the abdominal wall incision of a rat onto the microscope stage for 1 h. It was shown that hyperthermia intensified microcirculatory disorders and stimulated destructive processes in tissues and hypothermia promoting microcirculation and decreasing metabolism and restrained the development of these processes. Important peculiarity of the microvascular response to ischemia, hyper- and hypothermia was revealed: heterogeneity of the reaction of different parts of microvascular bed. Appropriate evaluation of the microcirculation state in such conditions can be obtained taking into account not only the qualitative character of microvascular reaction but also an extent of this reaction manifestation in different parts of microvascular bed.     

Thyrotropin-releasing hormone stimulates intestinal transit in young rats

The effect of intracisternal injection of thyrotropin-releasing hormone (TRH) on small intestinal transit of a charcoal bolus was investigated in 14-, 21-, 28- and 35-day-old and adult rats. Intracisternal TRH (15 micrograms in 2 microliters) was administered, and transit (distance traveled by the charcoal) was measured 120 min later. In all age groups, intracisternal TRH increased charcoal transit significantly (P less than 0.05) as compared to saline-treated controls. This increase in transit was not mimicked by intravascular TRH, and it was blocked in all age groups by prior intraperitoneal injection of atropine (2 micrograms/g body weight). Vagotomy blocked TRH-induced increases in small intestine transit in rats of 28 days and older. Prior intraperitoneal injection of the antiserotonin compound, cyproheptadine (1 microgram/g body weight) reduced TRH-induced increases in small intestine transit in all age groups. These results demonstrate that centrally administered TRH stimulates small intestine transit through both cholinergic and serotonergic mechanisms in rats as early as 14 days of age.     

Influence of age on Cu/Zn-superoxide dismutase and indole 2,3-dioxygenase activities in rat tissues

The aim of this study was to investigate in vitro the variations with age of the activities of the two antioxidant enzymes Cu/Zn-superoxide dismutase (SOD) and indole 2,3-dioxygenase (IDO) in metabolically active tissues of rats of various ages. In rats aged one week and 2-3 months the highest Cu/Zn-SOD activity was found in the liver and the lowest in the small intestine. At 12 and 18 months of age, the activity was higher in the brain and kidneys, when compared to the small intestine, lungs and liver. Cu/Zn-SOD activity decreased significantly after 2-3 months of age with advancing age in all tissues examined. In newborn rats IDO activity was present only in the small intestine. In the group of rats aged 2-3 months, the highest specific activity was observed in the small intestine and the lowest in the lungs and kidneys, whereas at 12 months of age, the highest IDO activity was found in the brain, with kidneys presenting the lowest activity. At 18 months, IDO returned to be more elevated in the small intestine. At 12 months of age the values of IDO in the tissues varied slightly, while at 18 months similar activities were found between the lungs and brain and between the small intestine and kidneys. In relation to age, IDO specific activity declined in the small intestine, after 2-3 months of age. In the lungs, the activity remained unchanged; in the brain and in the kidneys activity decreased significantly from 2-3 to 18 months of age. In conclusion, this study demonstrates an age-related decline in Cu/Zn-SOD and IDO activities, the two enzymes responsible for scavenging O2*-.     

Protein synthesis during the developmental growth of the small and large intestine of the rat.

The developmental growth and associated changes in protein synthesis were measured (in vivo) in the combined small and large intestine from 18 days in utero to 105 weeks post partum. Similar post-natal (3-105 weeks) changes were also studied in the separated large and small intestine, and in the mucosal and muscularis externa + serosal layers of the small intestine. Although the protein and nucleic acid contents of the whole intestine increased throughout both pre- and post-natal life, the maximal (11%) intestinal contribution to whole-body growth occurred 3 weeks after birth; this value declined to only 2.5-3.5% at both extremes of the age range studied. Between the 18-day foetus and old age the fractional rate of protein synthesis decreased from 107 to 61% per day. This developmental decline (43%) was, however, much smaller than that found in most other body tissues over the same period. Similar developmental trends (between weaning and senility) were found in both the small and the large intestine when studied separately, the small intestine in all respects contributing proportionately more than the large intestine to both the combined intestinal and whole-body values. At each age the large intestine possessed significantly lower fractional rates of synthesis and associated ribosomal activities. For the most part, the fractional synthesis rates in the mucosa and serosa of the small intestine were very similar, with each declining slightly with increasing age. These developmental changes are discussed with respect to functional aspects within the gastrointestinal tract.     

Vascularization of the myenteric plexus in the small intestine of pigeons]

By means of light and electron microscopy vascularization of the myenteric plexus has been studied in the pigeon small intestine. Ganglia of the plexus, their cell composition, ultrastructure of neurons have been described. Links of the microcirculatory bed of the intramural ganglia are characterized, interrelations of capillaries with neurons are described, quantitative estimation of microhemovessels, surrounding the microcirculatory bed of the myenteric plexus in the intestinal wall in birds and mammalia.     

Intestinal absorption of peptides peptide uptake by small intestine of Rana pipiens

The absorption of glycyl-l-leucine is studied using the small intestine of Rana pipiens perfused through the vascular bed. It is found that the transfer into the vascular bed of glycine and leucine from the peptide in the lumen occurs in part by a process independent from those for the transfer of the free amino acids. This process is particularly effective for the transfer of glycine.     

Resistance and capacitance functions of gastric vessels under the action of noradrenaline

In acute experiments on cats, the gastric vascular bed being perfused under constant blood flow, the actions of gastric vessels was investigated using newly elaborated approach to their humoral isolation. Increased doses of noradrenaline elicited the dose-dependent constrictive response of gastric arterial vessels. Perfusion pressure increase in the gastric vascular bed under action of the minimal dose of noradrenaline was more pronounced, than in the intestinal vessels. The capacity of the gastric vascular bed under action of the drug changed in different manner, mostly increased, but could be decreased as well. In contrast to the small intestine the gastric vessels are characterized by more pronounced action of noradrenaline on blood depoting processes.     

The effect of alcohol on zinc absorption

Two methods of intestinal perfusion are described and used to study the effecs of alcohol on zinc absorption in the rat small intestine. The first method used perfusion of the lumen of the rat small intestinein situ without interruption of the vascular supply. During perfusion with a zinc-containing medium (with and without alcohol), alcohol was found to have no effect on net zinc uptake from the lumen of the intestine. However, there were significantly higher serum zinc concentrations recorded in the rats perfused wih the zinc and alcohol, 28.8 μmol/L, when compared with a group perfused without alcohol, 19.1 μmol/L (P < 0.01). The second method used simultaneous perfusion of the lumen of the rat small intestine, with constant-rate perfusion of the vascular bed with an artificial blood supply. In this experiment with a zinc-containing medium, with and without alcohol, there was no difference noted in zinc absorption from the lumen of the intestine, or release into the artificial blood supply. Therefore, in conclusion, alcohol does not appear to directly influence zinc absorption by the mucosal cells of the small intestine.     

The role of insulin-like growth factors in small intestinal cell growth and development.

IGF-I and IGF-II receptors are expressed in the small intestine of mammalian species, as are the genes to synthesize both peptides. IGF binding proteins are also expressed in the intestine. IGF-I and IGF-II mRNA are highest in fetal and newborn tissues and decrease with age. IGF-I mRNA is present in the adult small intestine, and is associated with the submucosal regions and crypt cells. IGF-I and IGF-II receptor binding to the small intestine is higher in newborn animals and decreases with age. Both receptors are more concentrated in the crypt than villus regions, but IGF-II binding is higher than IGF-I in all regions. IGF-I receptors are associated with the submucosal region of the small intestine, whereas IGF-II receptors are more abundant in the mucosal cells. Administration of IGF-I either orally or by osmotic pump generally has no affect on small intestinal weight or length, but does increase mucosal cellularity. LR3-IGF-I administration by osmotic pump affects the small intestine similarly to IGF-I, although with a higher potency. In the few studies in which IGF-II was administered, increased gut mass was observed in adult rats, but not newborn rats or pigs. Significant effects on mucosal expression of disaccharidases was achieved with either oral or subcutaneous IGF-I or oral IGF-II. Administration of IGF in models of intestinal hypertrophy and atrophy are also reviewed.