Effect of potassium deficiency on carbon dioxide,cation, and phosphate content of muscle,with a note on the carbon dioxide content of human muscle

Albino rats weighing 160 to 175 gm. were fed a complete synthetic diet containing 0.003 per cent potassium and 0.7 per cent sodium for 40 days. Controls were given the same diet plus adequate added potassium. 1. Data from analyses of serum and skeletal muscle showed (a) a fall in serum chloride concentration and an increase in serum carbon dioxide concentration and pH in the potassium-deficient rats; (b) increases of sodium, magnesium, and calcium and a decrease of potassium in the muscle of the potassium-deficient rats; (c) no change of muscle chloride or carbon dioxide concentrations in the potassium-deficient rats. (2) Application of the Wallace-Hastings calculations to these data revealed (a) intracellular pH of the skeletal muscle of the normal rat to be 6.98 +/- 0.08; (b) an increase in serum partial pressure of carbon dioxide (pCO(2)) in potassium deficiency, together with increases in concentrations of [H(2)CO(2)] and [HCO(3) (-)] per kg. extracellular water and [H(2)CO(3)] per kg. cell water; (c) a decrease in values for [CO(2)] and [HCO(3) (-)] per kg. intracellular water; (d) a fall of intracellular pH in potassium deficiency to 6.42 +/- 0.05. (3) Analyses of sacrospinalis muscle from five men undergoing operation for ruptured intervertebral disc showed a mean value of 9.46 +/- 1.31 mM carbon dioxide per kg. blood-free tissue. Some problems of interpretation of data are briefly discussed.     

Regional differences in water content,collagen content,and collagen degradation in the cervix of nonpregnant cows

The cow could be a suitable model for studies concerning functional changes of the cervix. However, as in many species, the bovine cervix becomes softer in texture during the follicular phase of the estrous cycle compared to the luteal phase. In the present study, we explored if changes in the collagen network take place that could be responsible for this phenomenon and if regional differences in water content, collagen content, and collagen degradation along the cross-sectional and longitudinal axes of the cervix were present. Two groups of nonpregnant animals with different progesterone status were studied. One group (n = 11) was under high progesterone influence, and the other group (n = 12) was under low progesterone influence. The water content was derived from the weight of the samples before and after lyophilization. The collagen content and the ratio of collagenous to noncollagenous proteins (hydroxyproline:proline ratio) were determined by performing amino acid analysis on hydrolyzed samples using high-performance liquid chromatography. Collagen denaturation was quantified with a colorimetric assay by determining the amount of hydroxyproline released from samples treated with alpha-chymotrypsine. The water content of the superficial layer of the submucosa was always significantly (P < 0.01) higher than the water content of the deep layer in the vaginal, mid, and uterine segments, but this was unrelated to the progesterone status of the animals. No effect of the tissue layers or of the progesterone status of the animals on the collagen content was observed, but an effect of segment was noted. The collagen content (mug/mg dry wt) in the vaginal segment of the cervix was significantly higher than in the mid (P < 0.05) and the uterine (P < 0.01) segments. The hydroxyproline:proline ratio showed the same pattern as the collagen content. The percentage of collagen denaturation in the superficial layer was always significantly (P < 0.01) higher than that in the deep layer, but no effect of the progesterone status or of the segment along the longitudinal axis was seen. It is concluded that regional differences in collagen biochemistry are present in the cervix of nonpregnant cows, which may account for the difference in firmness of different parts along the circular or the longitudinal axis of the cervix. However, differences in texture of the cervix between the two groups of cows could not be explained by differences in the collagen content, percentage of collagen denaturation, or water content.     

Effect of phalloidin on liver actin distribution,content, and turnover

Phalloidin increases F-actin microfilament content and actin-directed immunofluorescence in hepatocytes in vivo and also increases actin polymerization and the stability of F-actin in vitro. We studied the sensitivity of immunofluorescent staining of actin to an actin depolymerizing factor (ADF) as well as actin content, degree of polymerization, and turnover in livers of in vivo phalloidin-treated rats. Pretreatment with ADF abolished anti-actin antibody (AAA) staining of normal liver but did not modify staining of livers from phalloidin-treated animals. Plani-metric analyses of SDS-polyacrylamide gels snowed the percent actin of total protein was increased by approximately 40% and the absolute amount of actin by approximately 43%, ten days after daily phalloidin treatment (50 μg/100 gm body weight). Similar but smaller changes could be seen after one day of treatment. Ultracentrifugational analyses of liver extracts indicated no change in the amount or proportion of G-actin but a 194% increase in the proportion of F-actin in ten-day treated animals, changes also apparent in one day animals. Neither the relative fractional rate of actin synthesis nor its synthesis as a percent of total protein synthesis was altered either at one-day or ten-day post-phalloidin treatment. Dual-isotope experiments indicated that the rate of actin degradation was decreased selectively in the one- to three-day period -following drug treatment. Thus, phalloidin appears to stabilize actin against the depolymerizing actions of ADF, increases the proportion of F-actin without altering the size of the G-actin pool, and causes accumulation of actin by decreasing its relative rate of degradation.     

Leptin对下丘脑LHA、VMH、PVN的RNA含量和体脂肪的影响

目的:探讨Leptin对下丘脑外测区(LHA)、腹内侧核(VMH)和室旁核(PVN)的RNA含量和脂肪沉积的影响.方法:通过小鼠注射Leptin,连续注射14d,70日龄时将动物宰杀,取LHA、VMH和PVN的组织,用荧光显微数字成像系统和Image Pro plus图像分析,测RNA.结果:Leptin引起生长期小鼠LHA和VMH的RNA含量显著增高(P＜0.01、P＜0.05),PVN的RNA含量降低,腹腔脂肪沉积显著减少(P＜0.05).结论:Leptin能引起LHA和VMH的功能加强,且两者都均与腹腔脂肪沉积呈负相关.     

Effects of nickel on the rates of endocytosis,motility, and proliferation inTetrahymena and determinations on the cell content of the metal

Protoplasma - At concentrations above 1 mM, nickel has a dose-dependent effect on the rate of food vacuole formation in cells in the growth medium, proteose peptone (PP); total inhibition of...     

Effects of carbonized and dried chicken manures on the growth, yield, and N content of soybean

The present study was conducted to investigate the effects of nitrogen derived from dried or carbonized chicken manure on growth, nodulation, yield and N content of soybean. ¹⁵N labeled chicken manure used in this study was obtained from the droppings of chicken fed on hulled rice grown under field conditions and fertilized with ¹⁵N-labeled stable isotope ammonium sulphate and potassium nitrate fertilizers. Carbonized chicken manure was made by heat treatment in a muffle furnace in our laboratory. This study was conducted in pots filled with clay loam soil. Results from the study show that the application of carbonized chicken manure increased soybean seed yield by 23% and 43% for the 50 and 100 kg N ha⁻¹ rates respectively. Dried chicken manure application increased soybean seed yield by 7% and 30% for the 50 and 100 kg N ha⁻¹ rates respectively. There was no difference in the N manure yield of both manures when applied at the same rate. The percentage ¹⁵N recovery was 17.6% and 8.9% for carbonized chicken manure, 19.2% and 10.5% for dried chicken manure at 50 and 100 kg N ha⁻¹ rates respectively at peak flowering stage of soybean growth. We found high total nitrogen yields of soybean at the rate of 100 kg N ha⁻¹ for both manures. There was a positive relationship between number of nodules and seed yield of soybean. Total N content also showed positive relationship with number of nodules and seed yield of soybean. We supposed that the higher P content of carbonized chicken manure is responsible for the higher seed yield and nodule growth compared to dried chicken manure.     

淡水湿地种子库的研究方法、内容与展望

种子库是指存在于土壤表面和土壤中全部存活种子的总和.种子库的研究是深入探讨湿地植被结构、功能与动态等方面的重要基础,同时也是对湿地生物多样性研究的一个重要补充,对于了解植被演替动态、植被更新和受损湿地植被重建与恢复具有指导意义.本文结合国内外淡水湿地种子库研究现状,对湿地种子库的形成、研究方法以及湿地种子库时空格局、种子库与地表植被的关系、水文变化对湿地种子库的影响、湿地种子库在湿地恢复中的应用等主要研究内容进行了系统的总结;同时对湿地种子库的时间动态、种子库的分类、种子库与地表植被的关系、湿地恢复重建及湿地景观营造等研究进行了展望.     

The polyphosphoinositide content of the leucocyte, erythrocyte and macrophage

1. The polyphosphoinositide content of macrophages and the cell membranes of leucocytes and erythrocytes was determined by an extension of the `acid-hydrolysis' procedure of Dawson & Eichberg (1965). The estimation was controlled by adding a little highly radioactive polyphosphoinositide to the tissue extracts before fractionation. Several standard methods for determining polyphosphoinositides gave low recoveries when applied to leucocytes, and it is suggested that these cells contain materials that form complexes with the polyphosphoinositides and interfere with the assay. 2. The method for the preparation of leucocyte cell surface membranes has been modified.     

Effect of rutin on the cholesterol content of the lymph, blood and tissues of the dog

It has been discovered in experiments on mongrel dogs anesthetized with morphine and hexenal that intravenous injection of rutin (3 mg/kg bw) reduced the concentration of total, esterified and free cholesterol in blood serum, with the exception of free cholesterol level in arterial blood, which increased. Under the same conditions, the concentration of free and esterified cholesterol in thoracic duct lymph ascended. In the popliteal lymph node, gastrocnemius muscle and liver, the content of total cholesterol appreciably dropped as compared to control. Rutin has been found to accelerate the lymph flow and to raise cholesterol resorption from the interstitial space. It is inferred that lymph plays an important part in cholesterol transport in the body.     

Effect of dopamine and dopamine-receptor blockade on in vitro renin release, tissue renin content and tissue cyclic AMP content in the rat

This study evaluated the in vitro renin release, tissue cyclic AMP content (TcAMPc), and tissue renin content (TRC) changes with time, in response to administration of dopamine (DOP) and of the dopamine-receptor blocking agent pimozide (PIM) to renal cortical slices from sodium deficient (SD) rats. Addition of 10(-3)M DOP to the slice preparation resulted in a gradual stimulation of RR with time, which was significantly different from that seen in control samples after 60 min of incubation. In contrast, TcAMPc of the DOP-treated samples was significantly greater than that of controls after 5 min of incubation. At 60 min, mean TRC of DOP-treated samples was greater than that of controls but not significantly. Two PIM doses (10(-8)M and 10(-6)M, whether added alone or together with 10(-3)M DOP to the cortical slice system, significantly increased RR in each instance while simultaneously depressing TcAMP content markedly below that of unstimulated controls at all incubation times examined. Mean TRC of pimozide-treated samples was also lower than that of controls by 60 min. These in vitro data in the SD rat suggest that: 1) stimulation of renin release by DOP is time-dependent and is mediated by a TcAMP-generating mechanism, and 2) the increase in renin release by PIM administration appears to involve pharmacological inactivation of TcAMP-generating pathways and disruption of membrane permeability, leading to uncontrolled RR.