Partition of ketone bodies into cholesterol and fatty acids in vivo in different brain regions of developing rats

The proportions of labeled ketone bodies and glucose incorporated into cholesterol and fatty acids in different regions of the brain in developing rats were compared. In cerebrums of 15- and 18-day-old rats, the ratios of dpm cholesterol/dpm fatty acids incorporated from [3-¹⁴C] acetoacetate and [3-¹⁴C] β-hydroxybutyrate ranged from 0.4 to 0.7, or 50 to 100% higher than values obtained with [U-¹⁴C] glucose. Much higher ratios were obtained with younger animals: from 1 to 12 days of life, the values ranged from 1.0 to 1.3 with [3-¹⁴C] β-hydroxybutyrate as substrate, and, from 1 to 5 days, with [3-¹⁴C] acetoacetate, they were 1.0 or greater. During the first 12 days of life, the ratios resulting from administration of [U-¹⁴C] glucose were 0.4–0.7. Clearly, a greater proportion of acetoacetate and β-hydroxybutyrate was incorporated into cholesterol during the first week of life than the remaining suckling period. Like cerebrum, other brain regions (i.e., cerebellum, midbrain, brain stem and thalamus) yielded higher ratios of dpm cholesterol/dpm fatty acids from [3-¹⁴C] β-hydroxybutyrate during the first 12 days of life than on day 17. Brain stem was the most active region for lipid synthesis, and had the highest dpm cholesterol/dpm fatty acid ratio. Since active synthesis of cholesterol from ketone bodies during the early postnatal period coincides with a period of rapid brain growth, the results indicate that ketone bodies are more important early in the suckling period as sources of cholesterol for brain growth.     

Fatty acids of cerebrosides in different regions of the developing foetal brain

The fatty acid composition of cerebrosides of developing foetal human brain and regional variations, if any, during intrauterine life were studied. While palmitic and stearic acids were the predominant normal fatty acids throughout intrauterine life, long chain fatty acids, like lignoceric and nervonic acids, which were low at early gestational ages, rapidly accumulated at term. Regional differences were observed in the concentrations of long chain normal fatty acids especially at term. Medulla oblongata showed a greater accumulation of long chain fatty acids as compared to the cerebellum and cerebrum. The distribution of 2-hydroxy fatty acids in different regions showed a pattern predominantly that of long chain carbon units, even at 34 wk of foetal life. A higher ratio of lignoeric to stearic acid in the case of normal fatty acids, probably indicative of chain elongation, was also evident in the case of medulla oblongata and cerebellum as compared to the cerebrum. The significance of these qualitative alterations in relation to rapid growth of brain prior to term and the process of myelination has been discussed.     

Ceramide,triglyceride, and sterol ester in normal human whole brain at different ages

Separation of ceramides from other lipids by two dimensional thin layer chromatography, characterization of ceramide in human brain lipid extracts, and the levels of ceramide, triglyceride, and sterol ester in human brain at different ages (25 week fetus and postnatal ages of 1 day, 3 weeks, 6, 8 and 22 months, and 6, 8.5, 10, 18, 33, 55 and 98 years) are described.     

Fatty acid composition of phospholipids in different regions of developing human fetal brain

The fatty acid composition of total phospholipids in different regions, viz., cerebrum, cerebellum and medulla oblongata, of developing human fetal brain was studied. All the brains analyzed in the present investigations were obtained from fetuses whose mothers belonged to the poor socioeconomic section of the population. Palmitic, oleic and stearic acids were found to be the dominant fatty acids, and the pattern was similar in all regions of the brain studied between the ages of 22 and 35 weeks. However at birth there appeared to be an increase in polyenoic acids at the expense of lower chain fatty acids, and these changes were of relatively higher magnitude in the cerebellum than in other regions studied. These changes, in terms of increase in polyunsaturated fatty acids near full term, coincided well with the already observed timing of an overall growth spurt of the brain a few weeks preceding birth.     

Effect of the lactose induced diarrhea on macronutrients availability and immune function in well-nourished and undernourished rats

In this study we compared the availability of nutrients in a balanced diet offered to young well-nourished and undernourished Sprague Dawley rats, with and without diarrhea. Malnutrition was induced by restricting food intake (50%) in one half of the rats for 2 weeks and diarrhea was induced by including 45% lactose in the diet after malnutrition had been established. During the experiment which lasted 8 d the animals were kept on the same feeding protocol but one half of the nourished and one half of the undernourished received lactose to induce diarrhea. The results showed that the inclusion of lactose at 45% in the diet caused a severe diarrhea both in the nourished and undernourished rats. This diarrhea however, resulted in a reduction in food intake and growth only in the well-nourished rats. In the rats with diarrhea the apparent digestibility of the diet and of its macronutrients decreased compared with the animals without diarrhea but this reduction was less apparent in the undernourished rats. Similar results were obtained in relation to the retention of nitrogen and energy. In this case, diarrhea was associated with retentions which were lower than those seen in the rats without diarrhea but the undernourished rats with diarrhea retained more energy than the well-nourished rats with diarrhea. Malnutrition resulted in lower packed cell volume, leukocyte count and thymus weight but diarrhea in the malnourished rats did not cause a further reduction in these variables as it did in the well-nourished animals. In general, these results indicate that in well-nourished rats, diarrhea had a negative effect whereas in the undernourished group it did not. It appears that the undernourished rats compensated their nutrient utilization so that diarrhea did not worsen their undernourished condition.     

A possible block in the intermediary metabolism of glucose into proteins and lipids in the brains of undernourished rats

[U-¹⁴C] Glucose or [1-¹⁴C] L-leucine was injected intraperitoneally into 28-day-old undernourished rats and control sibs who were killed 6 hr later. Brain proteins and lipids were extracted and the lipids fractionated by silicic acid column chromatography into cholesterol, glycolipids and phospholipids. The specific activity of labeled carbon derived from [U-¹⁴C] glucose in brain proteins was reduced by 25% in undernourished animals when compared to controls. A similar reduction was seen in the specific activity of brain lipids of undernourished animals: 14% for cholesterol, 21% for phospholipids and 35% for glycolipids. When [1-¹⁴C] l-leucine was used as a direct precursor of brain protein synthesis, the specific activity in the undernourished group was only 5% less than that found for the controls. This was not statistically significant. The results suggest that there may be a block in the intermediary metabolism of glucose in the brains of undernourished rats that reduces the availability of glucose carbon to the precursor pool used for protein and lipid synthesis.     

Phospholipid class and fatty acid composition of developing spinal cord in normal pigs and in congenital tremor (Myoclonia congenita)

Extracts of spinal cord lipids from normal pigs and littermates affected with myoclonia congenita were examined for lipid and fatty acid composition at 6, 10, 14, 21 and 30 days of age. A marked decrease in total crude lipid and in phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidylinositol (PI) occurred in spinal cord lipids of affected pigs. Cholesterol esters were absent from spinal and lipid extracts and no qualitative difference in ganglioside patterns were observed between normal and affected pigs at any age. Spinal cord lipid extracts from affected pigs had less oleic acid except at 30 days and more arachidonic, docosapentaenoic and docosahexaenoic acids than normal.     

丹参酮ⅡA对大鼠脊髓损伤后星形胶质细胞增殖的MAPK通路的影响

目的探讨丹参酮ⅡA(tanshinoneⅡA,TⅡA)对大鼠脊髓损伤(spinal cord injury,SCI)后星形胶质细胞增殖的MAPK通路的影响。方法建立大鼠SCI模型,获得星形胶质细胞,培养14 d后,采用免疫荧光法检测星形胶质细胞中胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)的表达;MTT法选择TⅡA抑制星形胶质细胞生长的最适浓度和时间;Western blot法检测MAPK通路各蛋白的磷酸化情况。结果星形胶质细胞中有GFAP特异性表达;TⅡA抑制星形胶质细胞生长的最适浓度为15μg/mL,最适作用时间为36 h;15μg/m L TⅡA作用0和4 h,星形胶质细胞中p-JNK高于8和12 h,ERK1/2和p38无变化。结论 TⅡA主要通过JNK依赖性途径对星形胶质细胞的生长进行调控。     

新型苯甲酸衍生物类流感病毒神经氨酸酶抑制剂的合成及初步活性评价

以4-氨基-3-碘苯甲酸甲酯为原料,经过一系列反应得到苯甲酸衍生物类流感病毒神经氨酸酶抑制剂I-IV,并经化合物II衍生得到化合物V-VII,结构经1HNMR,13CNMR,MS确证;用化学荧光法测定抑制率,测试选用流感病毒菌株H3N2（California/04）,H1N1（California/99）和B（Shanghai/02）,结果显示：在I-IV中,苯环C3位置侧链越大,化合物的活性越低;V-VII中,在苯环侧链α位的碳上引入羟基后比在β位碳上单羟基的化合物活性增强,这表明α位的碳上电子环境的变化对活性有较大影响;在苯环侧链α位的碳上含有单羟基的化合物VII具有对A型流感病毒最强的活性。     

Cholesteryl ester hydrolase activity in adrenal homogenates from normal and essential fatty acid-deficient female rats

Cholesteryl ester hydrolase was assayed in adrenal homogenates from mature female rats fed a control (corn oil-containing) or essential fatty acid (EFA)-deficient diet. Cholesteryl ester of 16∶0, 18∶0, 18∶1, 18∶2(n−6), 20∶4(n−6) and 22∶4(n−6) were used as substrates. In control rats, the unsaturated esters were hydrolyzed more rapidly than the saturated esters and cholesteryl arachidonate was the preferred substrate of the six investigated; cholesteryl oleate elicited the highest activity in the deficient group. Polyunsaturated esters were hydrolyzed at a significantly lower rate by homogenates from EFA-deficient rats than by those from control animals. The esters of 18∶1, 18∶2(n−6) and 20∶4(n−6) were hydrolyzed more extenstively in relation to their concentrations in adrenal tissue than were cholesteryl esters of 16∶0, 18∶0 and 22∶4(n−6). This difference was more pronounced in control than in EFA-deficient rats. No simple relationship of adrenal cholesteryl ester hydrolase activity to ester fatty acid structure or to nutritional essentiality was evident.     

Lactational changes in concentration and distribution of ganglioside molecular species in human breast milk from Chinese mothers

Gangliosides play a critical role in human brain development and function. Human breast milk (HBM) is an important dietary source of gangliosides for the growing infant. In this study, ganglioside concentrations were measured in the breast milk from a cross‐sectional sample of Chinese mothers over an 8‐month lactation period. The average total ganglioside concentration increased from 13.1 mg/l during the first month to 20.9 mg/l by 8 months of lactation. The average concentration during the typically solely breast‐feeding period of 1?6 months was 18.9 mg/l. This is the first study to report the relative distribution of the individual ganglioside molecular species through lactation for any population group. The ganglioside molecular species are made up of different fatty acid moieties that influence the physical properties of these gangliosides, and hence affect their function. The GM₃ molecular species containing long‐chain acyl fatty acids had the most prominent changes, increasing in both concentration and relative distribution. The equivalent long‐chain acyl fatty acid GD₃ molecular species typically decreased in concentration and relative distribution. The lactational trends for both concentration and relative distribution for the very long‐chain acyl fatty acid molecular species were more varied. The major GM₃ and GD₃ molecular species during lactation were d40:1 and d42:1, respectively. An understanding of ganglioside molecular species distribution in HBM is essential for accurate application of mass spectrometry methods for ganglioside quantification.     

Inferences concerning the amorphous regions in polyethylene of different morphologies

Using a liquid nitrogen quenching method for the measurement of the ppm of hydrogen dissolved in polythylene (PE) at atmospheric pressure, solubility data were obtained for the following types of samples of linear PE: bulk, single crystalline and extended chain. For samples of equal amorphous volume fraction, the hydrogen is about 10-fold more soluble in single crystalline PE than in bulk. The solubility in extended chain samples becomes more abnormal, the higher the crystallinity. No hydrogen dissolves in a perfect C₂₀ H₄₂ crystal. The excessive solubility in the single crystalline samples is interpreted in terms of more sorption sites in the folded part of the chains in the amorphous surface layers than in bulk PE. As the heat of sorption changes from endothermic to slightly exothermic in passing from the bulk to the single crystalline or extended chain samples, the sorption sites must pre-exist in the latter two types.     

Molecular thermodynamics of solutions in the normal and critical regions — I. Theory

The purpose of this work is to obtain parameters suitable for the correlation of activity coefficients which — unlike for example the van Laar constants — are independent of the pressure and the temperature of the system. Thus if the pressure-temperature-composition behaviour of a liquid mixture is known at one temperature, parameters correlated on the basis of these data may be used in the prediction of the pressure-temperature-composition behaviour at all other temperatures and pressures.First a working equation for the calculation of activity coefficients is derived using the methods of molecular thermodynamics. The method is based on the van der Waal's two-fluid model and a statistical mechanical formulation of the principle of corresponding states in conjunction with a simple two parameter equation of state. The two parameters in the equation of state are left as parameters to be determined in the derived working equation. The parameters are determined by fitting the working equation to pressure-temperature-composition data at one isotherm. The parameters obtained in this manner are then used in the derived working equation to predict activity coefficients at all other temperatures and pressures of the system.     

Comparative study of lipids in mature seeds of six Cordia species (family boraginaceae) collected in different regions of Brazil

The oil content, FA, and lipid class composition of the mature seeds of six Cordia species were analyzed. Mature seeds of each species were collected in their natural habitat from 2002 to 2004. The total lipid content varied from 1.9% to 13.2%, there beings significant differences between the results found in different years for each species and between the species analyzed. The contents of FFA varied from 2.0% to 7.9% of total lipids. Neutral lipids (NL) were the largest class, making up between 89.6% and 96.4% of the total lipids; the phospholipids (PL) were the second largest class (3.0% to 8.9% of the toal lipids), and the glycolipids (GL) were the smallest class (0.6 to 3.4%). The presence of GLA was determined in each class of lipids; it is predominant in the NL. Levels of GLA ranged from 1.2% to 6.8% of total seed FA. This is, to our knowledge the first study of lipid composition in seeds of species of Cordia from Brazil.     

Distribution of the molecular species of phospholipids in human umbilical cord blood

The composition of phosphatidylcholine (PC) and sphingomyelin (SM) was studied in cord blood lipoproteins to determine whether equilibration of the molecular species of phospholipids among lipoproteins was comparable with that reported for adults. The molecular species distributions of PC in low density lipoprotein (LDL) differed from that of high density lipoprotein (HDL). Whereas LDL PC was richer in combinations of fatty acids with 16 and 18 carbon atoms than HDL, the HDL was markedly enriched in combinations of fatty acids with 18 and 20 carbon atoms. Sphingomyelins in LDL were richer in palmitic acid than HDL while HDL had a greater proportion of long chain sphingomyelin than LDL. The molecular species of PC and SM do not equilibrate in cord blood. The results for the SM distributions were similar to other reports for adult human lipoprotein. However, the marked differential distribution of PC among lipoproteins appears unique to cord blood. The mechanisms responsible for equilibrating PC among lipoproteins are less well developed in the neonate when compared with the adult.     

Composition and concentration of lipoproteins in the serum of normal rats and rats deficient in essential fatty acids

A comparison is made of the concentration and chemical composition of serum lipoproteins of normal rats and rats deficient in essential fatty acids. The concentration of very low density lipoproteins (VLDL) and of low density lipoproteins (LDL) in serum of deficient rats is about half that found in normal rats, but the concentration of high density lipoproteins (HDL) is higher than normal and they contain an increased amount of cholesterol esters. The proportion of cholesterol that is esterified is much greater than normal in the serum of deficient rats. The deficiency of essential fatty acids also appears to result in compensating changes occurring in the composition of serum lipoproteins. In both VLDL and LDL of deficient rats the proportion of protein is raised and that of phospholipid lowered compared to normal, while the proportions of trigly ceride and cholesterol esters are unchanged.     

慢病毒介导siRNA对大鼠脊髓组织细胞外信号调节激酶1/2及核因子E2相关因子2基因的影响

目的评价慢病毒介导细胞外信号调节激酶1/2(extracellular-signal-regulated kinase 1/2,ERK1/2)-si RNA及核因子(nuclear factor,NF)E2相关因子2(NF-E2-related factor 2,Nrf2)-si RNA进入大鼠局部脊髓组织的转染效果。方法采用NYU撞击法构建SD大鼠脊髓损伤模型(模型组),使用微量注射器将含荧光慢病毒载体(LV-Nrf2-RNAi和LV-ERK1/2-RNAi)稀释液注射至其脊髓T10水平背侧深约0.8 mm处,荧光显微镜下观察不同时间点(12 h、24 h、72 h、7 d及14 d)转染效果。以只切除椎板,不打击脊髓的大鼠作为假手术组,在模型组和假手术组中同时设转染组和未转染组。取大鼠脊髓组织,采用RT-PCR及Western blot法检测转染后7 d时ERK1/2及Nrf2基因m RNA转录及蛋白表达水平。结果与假手术组相比,模型组大鼠脊髓组织在慢病毒转染后各时间点均有较强的荧光表达,病毒转染7 d以内,荧光强度与时间呈正相关,在转染7 d后达到高峰。转染7 d后,假手术组与模型组中ERK1/2及Nrf2基因m RNA转录及蛋白表达水平均较未转染组明显降低(P均0.05)。结论慢病毒介导si RNA转染大鼠脊髓组织,能够有效沉默ERK1/2及Nrf2基因的表达。     

Efficacy evaluation of the molasses supplementation in normal and depleted rats diet

Molasses, a sugar cane by-product, has been consumed in Brazil since colonial times. The efficacy of molasses added to the diet of normal and depleted laboratory animals on growth and hemoglobin was tested. Forty weaning males rats, of 21 days of age, were divided into four groups of ten animals: Control (casein diet with 10.14% protein); Molasses (casein diet with 10.14% protein and 12.50% molasses); Depleted Control and Depleted Molasses, the later two submitted to protein depletion for the first 7 days of the trial. Animals were weighed at weaning (initial weight) and at the end of the experiment (final weight) and were fed the experimental rations and water ad libitum for 28 days (normal animals) and 21 days (depleted animals). Consumption was registered in order to calculate the Food Efficiency Ratio. At the end, animals fasted for 10 hours, killed and blood was collected by cardiac puncture to determine hemoglobin levels. Weight gain in all groups did not show statistically significant differences. Molasses fed animals presented a small, but not significant increase in hemoglobin levels, compared to the control groups. Considering the possible deleterious effects of a high sugar diet, that can originate furfural during food processing, it is necessary to conduct more studies to evaluate the utilization of these products for human consumption.