The neural apparatus of the small intestine of piglets after administration of a growth stimulator kormogrisein]

By means of classical neurohistological techniques, phase contrast microscopy and morphometry, a comparative investigation has been performed concerning the development of the intramural nervous apparatus in the small intestine, normal and at application of cormogrisine. The structural peculiarities of morphogenesis are considered together with signs of activation and inhibition of the neurons growth in tissue culture. A number of morphological criteria, demonstrating an increased extrusive activity and enhancing potensity of the neurons growth have been revealed. The number of nervous processes becomes greater; degree of their ramification increases; a part of neurons of Dogiel II type turns into multiprocessive neurons with some signs of Dogiel I type cells; growth cones and arcadian structures are present; giant processes appear; thick nervous fasciculi are formed; volume of the neuron bodies increases more intensively. After application of cormogrisine for 2 months a definite neurostimulatory effect is revealed; it demonstrates a more intensive morphogenesis of the small intestine nervous of Physiology, USSR, Academy of Medical Sciences, Leningrad.     

Effect of tetracycline group antibiotics on the barrier properties of the small intestine epithelium]

The effect of 5 tetracyclines on the barrier and transport properties of the small intestine epithelium was studied. The barrier properties were estimated by a change in the ionic selectivity and conductivity of the epithelium, as well as by enterocyte linkage. The current of the short circuit served the characteristics of the Na transport system state. Dimethylchlortetracycline, methacycline and oxytetracycline in concentrations of 10(-7) g/ml decreased the epithelium conductivity and increased the cell linkage. Tetracycline and methacycline in concentrations of 10(-9) g/ml had an analogous effect. The effect was observed 10--20 minutes after the start of incubation with the substance. No effect on the current of the short circuit was observed within the concentrations of 10(-4) to 10(-9) g/ml. It is suggested that the decreased conductivity and increased linkage are due to adsorption of the tetracycline molecules in the region of close cell contacts.     

Significance of the intervals of hydroxyurea administration for epithelial damage to the small intestine in mice

The states of the murine small intestinal epithelium 6, 30 and 78 h after the end of the multiple regular injections of hydroxyurea (HU) were analysed with the aid of the light and electron microscopy. The course of 6 regular injections of 5 mg/mouse HU was begun 24 h after the initiating gamma-irradiation in a dose 200 rad and the interval between injections was varied from 7 to 19 h for different experimental groups of mice. The analysis of the epithelial state revealed two minima of the tissue damage which correspond to the courses of HU injections with the intervals close 9 h and 16.5 h.     

Infection of mice with oral administration of trophozoites of Giardia muris]

For the last 9 years we have used Giardia muris for chemotherapy research, passing trophozoites scraped from the mouse small intestine into fresh mice, by gavage. More or less every trophozoite administered orally reproduces in the intestine, as shown by quantitative studies in groups of young, specific pathogen-free mice, treated with 1, 3, 10, 30 or 100 Giardia each. After 7-9 days the number of protozoa in the intestine diminished somewhat, in the groups infected with the largest number of trophozoites.     

Radioprotective effects of oral 17-dimethylaminoethylamino-17-demethoxygeldanamycin in mice: bone marrow and small intestine

Background

Our previous research demonstrated that one subcutaneous injection of 17-Dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) 24 hours (h) before irradiation (8.75 Gy) increased mouse survival by 75%. However, the protective mechanism of 17-DMAG is currently unknown. The present study aimed to investigate whether oral administration of 17-DMAG was also radioprotective and the potential role it may play in radioprotection.

Results

A single dose of orally pre-administered (24, 48, or 72 h) 17-DMAG (10 mg/kg) increased irradiated mouse survival, reduced body weight loss, improved water consumption, and decreased facial dropsy, whereas orally post-administered 17-DMAG failed. Additional oral doses of pre-treatment did not improve 30-day survival. The protective effect of multiple pre-administrations (2?3 times) of 17-DMAG at 10 mg/kg was equal to the outcome of a single pre-treatment. In 17-DMAG-pretreated mice, attenuation of bone marrow aplasia in femurs 30 days after irradiation with recovered expressions of cluster of differentiation 34, 44 (CD34, CD44), and survivin in bone marrow cells were observed. 17-DMAG also elevated serum granulocyte-colony stimulating factor (G-CSF), decreased serum fms-related tyrosine kinase 3 ligand, and reduced white blood cell depletion. 17-DMAG ameliorated small intestinal histological damage, promoted recovery of villus heights and intestinal crypts including stem cells, where increased leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) was found 30 days after irradiation.

Conclusions

17-DMAG is a potential radioprotectant for bone marrow and small intestine that results in survival improvement.

     

Studies on the function of blood-liquor barrier in newborn infants]

Simultaneous measurement of the electrolytic conductivity of the cerebrospinal fluid and the blood serum in newborns has revealed a concentration gradient suggesting an active transfer of electrolytes into the liquor space. The extent of this concentration drop is regarded as expressing the functional capacity of the blood-liquor barrier. Comparative investigations in healthy older children shown that constant values, corresponding to the adult age, are reached approximately at the end of the first year of life.     

Chicken intestine microbiota following the administration of lupulone, a hop-based antimicrobial

The use of antibiotic growth promotants in poultry rearing is a public health concern due to antibiotic resistance in bacteria and the harborage of resistance genes. Lupulone, a hop β-acid from Humulus lupulus, has been considered as a potential feed additive growth promotant. Here, the effect of lupulone was evaluated for its effect on the microbiota of the chicken intestine. The intestinal microbiota of broilers was quantified after the addition of 125 mg L(-1) lupulone to water and challenge with Clostridium perfringens. Microbial DNA was extracted from the broiler midgut and cecal sections and bacterial groups were quantified using real-time PCR. The predominant cecal bacterial groups were Clostridium leptum subgroup 16S rRNA gene Cluster IV, Clostridium coccoides subgroup 16S rRNA gene Clusters XIVa and XIVb and Bacteroides, whereas Lactobacillus, the Enterobacteriaceae family and Enterococcus dominated the midgut. Lupulone at 125 mg L(-1) significantly decreased the C. perfringens subgroup 16S rRNA gene Cluster I, which contains several pathogenic species, in both the midgut and the cecum and Lactobacillus in the midgut. No significant changes were noted in the overall microbiota for the cecum or the midgut. Lupulone warrants further evaluation as a botanical agent to mitigate C. perfringens overgrowth in antibiotic-free reared poultry.     

Promotion of non-rapid eye movement sleep in mice after oral administration of ornithine

We examined the effects of ornithine on the sleep-wake cycle by monitoring the electroencephalo-gram, electromyogram, and locomotor activity of freely moving mice after oral administration of it at lights-off time (18:00). Ornithine (1.0 and 3.0 g/kg of body weight) increased the amount of non-rapid eye movement (non-REM, NREM) sleep for 2 h after its administration, with a peak at 60 min post administration, to 164% and 198%, respectively, of that of the vehicle-administered mice, without changing the amount of REM sleep. The administration of ornithine at a lower dose (0.3 g/kg of body weight) did not increase the amount of NREM sleep compared with the vehicle administration. Ornithine did not affect the power spectrum density of NREM sleep but increased the number of episodes of wakefulness and NREM sleep and that of transitions between wakefulness and NREM sleep, and decreased the mean duration of wake episodes in a dose-dependent manner for 2 h after the oral administration. These results indicate that ornithine increased the amount of NREM sleep without reducing the power spectrum density of NREM sleep.

     

Nafenopin-induced proliferation of peroxisomes in the small intestine of mice.

The effect of nafenopin on the epithelial cells of the small intestine of mice was studied. After 17 days the control and nafenopin-treated groups were sacrificed. The tissues were incubated in alkaline DAB medium. Ultra-thin sections of small intestinal tissue from both groups were examined by electron microscopy. Electron micrographs were prepared and examined stereologically so that any morphologic differences in the epithelial cell peroxisomes and mitochondria between the experimental and control groups could be evaluated quantitatively. In the nafenopin-treated group proliferation of peroxisomes occurred, as indicated by significant increases in volume, and surface and numerical density of these structures compared with controls. No such alterations were found in the mitochondria. Our results show that the response of small intestinal epithelial cells to nafenopin is analogous to that produced in hepatocytes by the same drug. Hepatocyte peroxisomes are supposed to be involved in lipid metabolism and it seems that small intestinal epithelial peroxisomes play a similar role.     

Crystallin synthesis in the lens of newborn mice]

Lenses of newborn mice were incubated for different time in the Hanks solution containing 14C-amino acids mixture. Syntheses of gamma-crystallin and subunits of alpha-crystallin were shown to start at the first minute of the incybation. The incorporation rate of 14C-amino acids into gamma-crystallin was twice as high as that into alpha-crystallin within 5 minutes of the incubation. The assembly of alpha-crystallin tetramers took place after 5 minutes from the beginning of the incubation. Preincubation with actinomycin D for 3 and 6 hours resulted in the decrease of 14C-amino acids incorporation into gamma-crystallin only. These data suggest that the synthesis of gamma-crystallin takes place on both short-lived and long-lived mRNAs. Alpha-Crystallin subunits are supposed to synthesize only on long-lived mRNAs.