Effect of electrostimulation of the hypothalamus on protein biosynthesis in organs of adult and aged rats

The effect of hypothalamus electrical stimulation on total protein biosynthesis was studied in skeletal muscle, heart, liver, adrenal cortex and thyroid gland of adult rats. In adult animals hypothalamus stimulation provokes a pronounced increase in 3H-leucine incorporation into total protein of all tissues, as well as into liver chromatin proteins. No significant changes were observed in protein biosynthesis when hypothalamus of old rats was stimulated. This can serve as evidence of age-related decrease in the ability of the hypothalamus to stimulate protein synthesis in peripheral tissues.     

Seroepidemiological study of coronavirus infection in children and adults in St. Petersburg

As the result of prolonged (17 years) observations of patients with acute respiratory infections hospitalized in basic departments of clinics of the Research Institute of Influenza, coronavirus infection was found to be the cause of respiratory diseases, on the average, in 12% of cases (in some years in 6.8% to 28.6% of cases). The analysis of extensive morbidity rates among different age groups of the population showed that children were affected by coronavirus infection 5-7 times more often than adults. Three year cycles of this infection were established. The periods of coronaviruses activation were accompanied by their detection in patient material by electron-microscopy, a sharp increase of immune response of patients as well as in the number of nosocomial infections and the proportion of the monoinfection of the coronavirus nature. Coronaviruses played the leading role among other viruses in the etiology of hospital respiratory infections. Mucosal antibodies to coronaviruses in the secretions of the nasal cavity proved to be more important than serum antibodies not only in protection from infection, but also in the pattern of clinical manifestations of the disease.     

Ionization constants and thermodynamic parameters of histidine and derivatives

The pK_a values for the proton dissociation of carboxyl, imidazolium, and ammonium groups for histidine and ten of its derivatives were determined electrometrically at seven temperatures in the range 10–40°C. The ΔH and ΔS values were estimated from the temperature dependence of the dissociation constants of histidine and its derivatives. These results and the pK_a values compared in terms of inductive effect suggest an ion-dipole interaction between the protonated amino group and the unprotonated imidazole ring. The charge and the solvation effects of the neighboring groups are the main factors that determine the imidazole group pK_a in histidine and its studied derivatives. The N^τ-H tautomer is favored over the N^π-H by 1.6 kcal/mol, indicating that the inductive substituent effect at position 4 of the imidazole ring is the major component in determining this tautomeric preference.     

Neurohormonal regulation of calcium in the cell

Neurohormone C (NC) is a glycopeptide isolated from bovine hypothalamus, which inhibits Ca-calmodulin (CaM)-dependent cAMP and cGMP phosphodiesterase (PDE) and is a regulator of Ca in the cell. Distribution of [⁴⁵Ca]CaCl₂ in the mitochondria and reticulum (SR) of heart and brain mitochondria and changes of Ca-binding proteins in these organelles under NC influence have been studied in the myocardium before and after isoproterenol-induced necrosis. Intraperitoneal administration of 80–100 mU of PDE inhibitory activity of NC to rats did not cause any noticeable changes in the protein content of intracellular organelles, but altered the affinity of certain proteins to⁴⁵Ca²⁺. This property of NC was especially noticable after isoproterenol necrosis. Necrotic injury of the myocardium induced Ca²⁺ storage in the mitochondria and SR of brain, and decreased the Ca²⁺ concentration in myocardial mitochondria. NC injection to the animals with necrosis was followed by Ca²⁺ release from all the studied organelles.     

Toxoplasma gondii isolates from free-range chickens from the northeast region of Brazil

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 152 free-range chickens (Gallus domesticus) from 22 municipalities in 7 northeastern states (Pernambuco, Rio Grande do Norte, Maranh?o, Bahia, Ceará, Sergipe, and Alagoas) of Brazil was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT); 81 (53.3 %) chickens had titers of 1:5 in 26, 1:10 in 9, 1:20 in 4, 1:40 in 1, 1:80 in 6, 1:160 in 6, 1:320 in 13, 1:640 in 6, 1:1,280 in 3, 1:2,560 in 6, and 1:5,120 or higher in 1. Hearts and brains of 81 seropositive chickens were bioassayed individually in mice. Toxoplasma gondii was isolated from 23 chickens with MAT titers of 1:5 or higher; the isolates were designated TgCKBr165-187. Five isolates killed all infected mice. Results indicate widespread contamination of rural environment in Brazil with T. gondii oocysts.     

Characteristics of the effect of implantation of the human ApoA1 gene on the condition of hepatocytes in rats of varying age

The results obtained show the essential changes in functional state of hepatocyte's plasmatic membrane due to the implantation of human ApoA1 gene to the rat liver. The changes in phospholipid composition, hyperpolarization, increase in activity of membrane bound enzymes, cytochrome P-450 and biosynthesis of liver total proteins have been found. The essential changes characterizing cell effect were more marked in the adult rats, and membrane effect in the old ones.     

Correlative links between superoxide dismutase, catalase and glutathione peroxidase activities in mouse liver

Qualitative and quantitative differences in correlative and regressive links between superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase were assessed in the mice liver by two- and three-dimensional statistical methods. Paired linear correlation analysis indicated SOD-CAT tandem as the correlatively acting enzymatic pair. Three-dimensional analysis revealed uniform response surfaces which exhibited higher activities at disproportional values of the other two and lower activities at proportional activities of the other two enzymes. The direct effect of the enzymes on each other was positive [table: see text] while the effect of their product was always negative.     

Effect of Andrographis paniculata extract on progesterone in blood plasma of pregnant rats.

The effect of the powdered extract of Andrographis paniculata leaves (APE), an active principle of Kan Jang tablets [standardized for content of andrographolide (4.6%) and 14-deoxo-andrographolide (2.3%) content (total andrographolids--6.9%)] on blood progesterone content in rats was studied. Peroral administration of APE during the first 19 days of pregnancy in doses of 200, 600, and 2000 mg/kg (i.e. doses 30, 90, and 300 fold higher than its daily therapeutic dose in humans) does not exhibit any effect on the elevated level of progesterone in the blood plasma of rats. Let us assume then that in therapeutic dose, Andrographis paniculata extract cannot induce progesterone-mediated termination of pregnancy.     

Reactivity with p-nitrophenyl acetate and interaction between the amino and imidazole groups of histidine and related compounds

The study of the reaction of p-nitrophenyl acetate (PNPA) with histidine and certain derivatives showed that the species in which the amino group is unprotonated (R(NH₂)Im) react with second-order rate constants ( ) that are higher than predicted by a Brønsted relation for a series of neutral amino acids. The reason for this behavior was investigated through an analysis of the kinetics of the reaction of PNPA with these compounds in order to assess the reactivities of the amino and imidazole groups in the two species . The rate constant for the reaction with the imidazole group ( ) of N^π-methyl histidine agrees with the value predicted by a Brønsted relation obtained from a series of model imidazole compounds. N^τ-Methyl histidine, however, is unreactive, indicating that N^τ is the reactive nitrogen in the imidazole ring of histidine. The values found for histidine, histidine methyl ester, and N^α-dimethyl histidine are lower than predicted by the Brønsted relation. This behavior was found to be due to low reactivity of the

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. The evidence presented suggests that the lower reactivity of is due to an ion-dipole interaction between the protonated amino group and the unprotonated imidazole ring, which displaces the tautomeric equilibrium toward the unreactive N^τ-H form. The higher reactivity of the imidazole group in the species R(NH₂)Im, relative to that in , is responsible for the observed high values for histidine, for histidine methyl ester, for N^τ-methyl histidine, and for N^α-dimethyl histidine, in contrast with the normal value found for N^τ-methyl histidine. The conclusions from this study of histidine and its derivatives support the proposal of an interaction between the protonated N-terminal amino group and the imidazole ring of His⁶ in the octapeptide hormone angiotensin.     

Coronavirus infection in immunodeficient patients with hemoblastosis and deficient hemopoesis

Coronavirus infection (CVI) was studied in 227 patients hospitalized in the clinic of the Research Institute of Hematology and Transfusiology in 1993-2003 with diagnosed acute and chronic leucosis, multiple myelogenic disease and aplastic anemia. Their blood sera and secretions of the nasal cavity were examined in the indirect hemagglutination (IHA) test with dried standard erythrocyte diagnostic preparations. CVI was shown to be activated in three year cycles in immunodeficient patients, which occurred, respectively, in 66.1, 56.9, 47.8 and 51.6% of cases in the above mentioned groups of patients. In 87% of cases CVI was associated with other respiratory pathogens, the following being prevailed: respiratory syncytial virus (37.9%), parainfluenza virus (32.2%) and Mycoplasma pneumoniae (36.8%). CVI was provoked by such factors as the course of the main disease and specific treatment, previous respiratory infections of other etiology with M. pneumoniae infection playing the leading role (60%). The most severe course of CVI was observed in patients with acute leucosis (in 75% of cases accompanied by lesions of lower respiratory tracts). The use of the highly sensitive IHA test made it possible to determine the potential for both serum and local antibodies production in the patients under observation.