Alpha-fetoprotein synthesis during liver regeneration in adult mice of different strains]

Alpha-fetoprotein (AFP) concentration was estimated by radial immunodiffusion in agar technique in the sera of adult mice of 12 inbred strains and F1 hybrids (SWR X B10D2 and B10D2 X SWR) during liver regeneration after CCl4 poisoning. Statistically significant difference in the AFP concentration was found in the male and female sera in 6 of 10 mouse strains studied. The following inter-strain differences were also revealed: the AFP mean levels in the sera of C57BL/6 and B10D2 strains were found to be significantly lower than the corresponding levels in the sera of the majority of the strains tested. F1 hybrids showed to occupy an intermediate position by the AFP content between the parental strains. Small, but statistically significant, differences were revealed between the groups of male F1 hybrids from the direct reciprocal crossings. It is suggested that the control of induction of the AFP synthesis during the liver regeneration in adult mice was realized on the polygene basis.     

Characteristics of liver regeneration and growth in 3-week-old mice of different strains]

Three-week mice of C57BL strain are characterized by low proliferative activity of hepatocytes during normal growth of the liver. Hepatocytes of mice of this strain also had low proliferative activity 44 hours after partial hepatectomy (16%). Mice of the same age, but of other strains (mongrel, CBA, CC57BR) had higher mitotic indices both during normal growth and during regeneration (42; 70 and 60%, respectively). This peculiarity in the mitotic activity of hepatocytes of mice of different strains was also present 7 days after the beginning of the experiment. The data obtained indicated the genetic determination of the level of proliferative activity of hepatocytes.     

Growth of Azotobacter chroococcum strains on different substrates]

Azotobacter chroococcum 34, actively growing on alpha-ketoglutaric acid, and Azotobacter chroococcum B and KL, which almost do not assimilate this acid, can grow on the majority of substrates of the tricarboxylic acid cycle and on glucose, with and without nitrogen. The rate of assimilation of alpha-ketoglutaric acid is several times higher in the cells cultivated in the presence of this acid than in the cells grown on other substrates. This difference seems to involve the mechanism of transport of alpha-ketoglutaric acid into the cell.     

Free amino acid pool in the brain of inbred strains of mice with different learning aptitudes]

GABA, glycine, taurine, putative inhibitory transmitters or modulators of the CNS are at a significantly lower level in the brains of SEC and DBA strains of mice which offer higher performances in avoidance and learning tests than in the C57 strain which scores poorly.     

泼尼松龙致不同品系小鼠药源性证候的比较

目的研究糖皮质激素药物作用于不同品系小鼠后肾上腺皮质功能抑制程度及其诱导药源性证候的差异性。方法选用ICR、BALB/c、C57BL/6J、KM和裸小鼠5种小鼠为实验对象,采用泼尼松龙进行干预。每种小鼠16只,其中正常对照组8只,泼尼松龙组8只。以0.5 mg/(kg·d)泼尼松龙连续灌胃14 d,每日观测小鼠体重,在给药第14天,运用小鼠辨证论治实验方法学检测小鼠中医四诊信息,次日处死小鼠,取脾、胸腺称重并计算脏器指数;运用ELISA检测血清皮质酮和ACTH含量;采用实时荧光定量PCR技术检测肾上腺Star、Cyp11a1、Cyp21a1、Cyp11b1、Cyp11b2基因表达;运用Western blot方法检测肾上腺LDLR、SRBI、StAR蛋白表达。结果与各自对照组比较:1)0.5 mg/(kg·d)泼尼松龙给药后第7天起ICR小鼠体重显著下降(P<0.01);给药后第13天起BALB/c小鼠体重显著下降(P<0.01);给药后第5天起C57BL/6J小鼠体重显著下降(P<0.01);给药后第13天裸鼠体重显著下降(P<0.05)。2)泼尼松龙导致ICR小鼠抓力显著下降以及躯干平均温度显著降低(P<0.05)。3)泼尼松龙导致ICR小鼠和裸鼠脾重量显著下降(P<0.01)以及裸鼠脾指数下降(P<0.05),泼尼松龙导致ICR、C57BL/6J和KM小鼠胸腺重量和胸腺指数均显著下降(P<0.01)。4)泼尼松龙显著导致BALB/c与KM小鼠血清皮质酮下降(P<0.05),也显著引起BALB/c小鼠血清促肾上腺皮质激素(ACTH)含量下降(P<0.01)。5)泼尼松龙显著下调ICR小鼠肾上腺Cyp21a1基因表达(P<0.05),下调C57BL/6J小鼠Star基因表达(P<0.01),下调KM小鼠Cyp11a1、Cyp21a1基因表达(P<0.01),下调裸鼠Star与Cyp21a1基因表达(P<0.05);且泼尼松龙抑制ICR小鼠肾上腺LDLR蛋白表达以及KM小鼠肾上腺StAR蛋白表达。结论泼尼松龙造成的小鼠药源性虚证主要表现为"气虚",涉及中医"肾藏象"与"脾藏象",其物质基础以肾上腺皮质类固醇激素合成酶分子表达被抑制以及垂体-肾上腺皮质轴功能被抑制为主;开展糖皮质激素药源性虚证研究建议首选ICR小鼠。     

Effects of microwaves on three different strains of rats

Confounding factors influencing the sensitivity of biological indicators of microwave exposure--lethality, colonic temperature (Tco), decreased body mass (dW), corticosterone (CS), thyrotropin (TSH), thyroxine (T4), free thyroxine (FT4), and prolactin (PRL) concentration--were studied in Long-Evans (LE), Wistar-Kyoto (WKY), and spontaneous hypertensive (SHR) rats. The microwave signal was 2.45 GHz amplitude modulated at 120 Hz. Test power density ranged from 1 to 50 mW/cm2 for 2 h. In contrast to the LE and WKY rats, the SHR rats were characterized by intolerance (death) between 40 and 50 mW/cm2 (9.2 to 11.5 W/kg). The lowest lethal Tco was 41.1 degrees C. Survivors including all the LE and WKY rats were capable of maintaining Tco lower than 41.0 degrees C. In general, strain of rat seemed to influence other bioindicators and to interact with power density on these bioindicators. Except for Tco and PRL, baseline for the various bioindicators varied among the different strains of rats. Responses of T4 and FT4 were limited in magnitude and inconsistent among strains of rats. In general, the magnitude of Tco increase was more pronounced in SHR than in WKY. Differences between SHR and LE, however, could be noted only at 1, 10, and 50 mW/cm2. Increased Tco, increased magnitude of Dw, increased CS, decreased TSH, and increased PRL (stress reactions) could be noted in rats exposed to 30 mW/cm2 (approximately 6 W/kg) or higher, irrespective of strain. At least two of three strains of rats (WKY and SHR) exposed to 20 mW/cm2 (approximately 4 W/kg) showed changes in Tco, CS, TSH, and PRL. At 10 mW/cm2 (2 W/kg), increased Tco could be found in all three strains of rats accompanied by changes in dW and TSH in LE, TSH in WKY, and dW and CS in SHR. At 1 mW/cm2 (0.2 W/kg), increased Tco could be noted in two of three strains (LE and SHR) and increased PRL in LE only. The smallest Tco increases for a consistent response (increased magnitude of response with power density) were 1.59 degrees C for dW, 0.70 degrees C for CS, 0.24 degrees C for TSH, and 0.97 degrees C for PRL. Tentatively, the threshold intensity for response to microwave exposure for rats could be considered as 2 W/kg or a 0.24 degrees C increase at 24 degrees C ambient temperature.     

Characteristics of the mitogenic activity of different staphylococcal strains]

The mitogens of human peripheral lymphocytes were detected in the metabolic products of 59 out of 71 S. aureus strains. The preparations of S. epidermidis were inactive. When stimulated with filtrates of various S. aureus strains, 72-hour lymphocyte cultures were found to have 0--46% of blasts. Two-year observation of a strain showed its stable mitogenic characteristics. The mitogenic properties of the preparations did not correlate with their coagulase, alpha-toxic, dermonecrotoxic, cytotoxic, enterotoxigenic, neutrophil-stimulating activity and the quantitative content of A protein.     

Rosette formation and humoral immune response to 2,4-dinitrophenol in mice of different inbred strains]

A study was made of the content of rosette-forming cells to DNP-ovalbumin in the spleen of mice of different inbred strains. The values of the rosette-forming cells and of the titre of serum agglutinins to the DNP-group in DNP--bovine gamma-globulin immunization of mice of these strains were determined. It was shown that there were interstrain differences in respect to the normal and immune rosette-forming cells and also humoral antibodies. There was noted a direct correlation between the number of the immune rosette-forming cells and the antibody titre in the serum of mice of the same inbred strain. Immune response (both by the content of rosettes in the spleen and by the antibody level) proved to be the minimal in mice with the highest level of rosette-forming cells. There proved to be no inverse relationship.     

Immunodepressant action of cyclophosphamide in different strains of mice

A study was made of the immunodepressive effect of cyclophosphamide (CP) on mice of 3 strains (BALB/c, CBA, and DBA/2) immunized with sheep red blood cells (SRBC). With the optimal immunizing dose of the antigen (5 X 10(8) SRBC) the most pronounced immunodepression was noted in DBA/2 mice, and with the high dose (6.2 X 10(9))--in DBA/2 and CBA mice. The CP action proved to depend on the dose of the antigen administered; in BALB/c mice a reduction in the number of the antibody-forming cells was the same with both SRBC doses, in DBA/2 mice an increase of the antigen dose led to reduction of immunode pression, and in CBA mice -- to its enhancement (with sufficiently high CP doses). Determination of the rate of oxidative CP hydroxylation by the liver microsomes of mice showed it to be comparatively low in DBA/2 and CBA mice, and much greater in BALB/c mice. It is supposed that the detected differences in the immunodepressive action of CP could be connected with different sensitivity of the target cells and (or) with the peculiarities of its metabolism in mice belonging to different strains.     

Age dependency of estrogen responsiveness in the uterus and adipose tissue of aromatase-knockout (ArKO) mice

Aging is often associated with weight gain caused by metabolic changes including an increase of body fat. In this study we assessed the impact of age on estrogen responsiveness in the uterus and adipose tissue (AT) in aromatase-knockout (ArKO) mice. ArKO mice at the age of three or twelve months respectively were treated s.c. with vehicle, E(2) (10 μg/kg BW/d) or genistein (15 mg/kg BW/d) for three days. In the ArKO mouse model we were able to demonstrate that estrogen treatment resulted in an age specific response pattern both on a physiological and molecular level. Assessment of basal gene expression levels revealed significant age dependent differences only for elevated Esr1 levels in the uterus and leptin levels in infrarenal fat as well as lower levels of Pparg in the gonadal fat tissue. Investigating age dependency of estrogen responsiveness we were able to show that the E(2) and genistein resulted in age related pattern of regulation of expression of Esr1 and Lep in infrarenal and gonadal AT as well as the uterine expression of Pgr, Ltf and Pparg. In conclusion, evidence is provided that aging has an impact on the effectiveness of estrogen regulated processes in uterus and AT of ArKO mice. It remains to be elucidated whether or not this is associated with weight gain caused by an increase in body fat mass.     

酿酒酵母两种不同嗜杀菌的比较研究

以酿酒酵母两种不同类型的嗜杀菌株ＳＫ４（Ｋ１型）和ＥＲＲ１（Ｋ２型）为材料,分析了不同嗜杀酵母的嗜杀特性,两株嗜杀酵母具有相互杀死作用,其嗜杀活性与菌体生长有关。ＳＫ４和ＥＲＲ１的嗜杀质粒的比较表明：Ｍ１－ｄｓＲＮＡ质粒和Ｍ２－ｄｓＲＮＡ质粒分子量分别为１．７ｋｂ和１．５ｋｂ,两株菌的Ｌ－ｄｓＲＮＡ质粒均为４．０ｋｂ。用高温和紫外线处理嗜杀酵母,嗜杀活性随之消失,消除菌中的Ｍ－ｄｓＲＮＡ质粒也相应     

Effects of SERM (selective estrogen receptor modulator) treatment on growth and proliferation in the rat uterus

Background  

Selective estrogen receptor modulators (SERMs) have been developed in order to create means to control estrogenic effects on different tissues. A major drawback in treatment of estrogen receptor (ER) positive breast cancer with the antagonist tamoxifen (TAM) is its agonistic effect in the endometrium. Raloxifene (RAL) is the next generation of SERMs where the agonistic effect on the endometrium has been reduced.