Lillemor Lewan

Knowledge and recognition of ecosystem services among the general public in a drainage basin in Scania, Southern Sweden

Human preferences are likely to depend on such things as knowledge and information, propaganda and advertising, and formal (laws) and informal (norms) institutions. We focus on knowledge about how nature works and how this may be manifested in recognition of ecosystem services among the general public. Participants and non-participants in a plant nutrient abatement programme with detention ponds in a river drainage area in Scania, Southern Sweden, were asked to rank some selected ecosystem services, classified as visible services, invisible services and services involving human activities in nature. Three studied groups of local actors were originally not familiar with the concept of ecosystem services, but the concept was easily grasped. The results of the study include the following findings: (1) The groups of local actors were consistent in ranking the groups of visible and invisible services higher than the group of services involving human activities, but there were considerable differences in their ranking of individual services. (2) The generally high priority given to invisible services can partly, but not fully, be explained by the existence of the abatement programme. (3) There was uncertainty regarding relationships among and the relative importance of different ecosystem services. (4) Some informants had multiple preferences. In fact the role people chose to play may have larger impact on preferences than the level of information. (5) Several interviewees objected to the idea of ranking services, and preferred to view nature as a whole. The results are discussed from a knowledge perspective, and we conclude that a widespread recognition of ecosystem services in policy and economics cannot be expected until the general public has gained some critical level of basic knowledge about functions in nature.

Modulation of 5-fluorouracil metabolism by thymidine: In vivo and in vitro studies on RNA-directed effects in rat liver and hepatoma

The effects of thymidine (TdR) co-administration on the cytotoxicity and incorporation of 5-fluorouracil (5-FU) into RNA of various tissues was studied in rats bearing an ascites hepatoma (AH 130). The role of pyrimidine degradation in determining the modulating effects of TdR on the formation of FU-RNA was studied in hepatocytes and AH 130 cells in vitro. TdR (500 mg/kg) potentiated the antitumour effect of 5-FU (150 mg/kg) and also increased host toxicity as judged by changes in body weight. TdR given alone did not significantly affect tumour growth and body weight gain. Examination of the effect of TdR on the incorporation of 5-FU into RNA revealed a differential modulation of RNA-directed toxicity in different tissues. Incorporation of 5-FU into RNA in tumour and bone marrow was increased 2- and 4-fold, respectively. In spleen and kidney the incorporation increased by approximately 50%, but the values did not reach statistical significance. In contrast, the incorporation into RNA of liver and intestinal mucosa was decreased to ca 35% of the control. TdR at concentrations of 40 microM-40 mM progressively inhibited the degradation of 5-FU and decreased the incorporation of 5-FU into RNA of hepatocytes in vitro. In AH 130 cells in vitro TdR did not significantly influence the metabolism of 5-FU and the incorporation into RNA. These results demonstrate that the enhanced incorporation of 5-FU into tumour RNA in vivo after pretreatment with TdR is related not to local effects on the tumour cells but rather to an increased bioavailability of the drug. Although co-administration of TdR did not selectively enhance the antitumour effect of 5-FU, a differential toxicity in host tissues was indicated by the modulated incorporation of 5-FU into RNA.

Metabolism of [5-3H]uridine in mouse and specificity for labeling of liver ribonucleic acid☆

Abstract 1. 1. The amount of [ 3 H]uridine incorporated into the acid soluble fractions of different mouse organs decreased in the following order: liver > kidney > spleen > thymus > brain. 2. 2. Ten minutes after injection, radioactively labeled uracil, dihydrouracil, β-UlP and β-alanine together amounted to 17% of the liver acid soluble radioactivity and 7% of that in blood, whereas 3 H 2 O made up 5% and 45%, respectively. 3. 3. At 10 minutes after injection the radioactivity of the uracil nucleotides and UDP-sugars together amounted to 35% of the total liver acid soluble radioactivity. 4. 4. The mouse liver seems to utilize [ 3 H]uridine and [ 14 C]orotate to a similar extent, but [ 3 H]uridine was more effectively incorporated int

Effects of partial hepatectomy on the utilization of 3h-thymidine in mice

Abstract 1. 1. Thymidine availability and specificity for DNA synthesis in various organs of hepatectomized and intact mice and the magnitude of catabolism of administered 3H-thymidine were investigated. 2. 2. The serum thymidine radioactivity 5 min after administration was 1.5 % of the total administered dose. The radioactivity decreased rapidly and was reduced to 1 % of the 5 min value after 2hr. 3. 3. β-AIB accumulated m serum until 20 min after injection and then its level decreased. The levels of thymidine and β-AIB radioactivity were increased 2–3 times after partial hepatectomy. 4. 4. Volatile radioactivity constituted 90% of the total serum radioactivity 60 min after injection. 5. 5. The level of acid soluble radioactivity in liver and kidney was higher, whilst that in spleen, thymus and cerebrum was lower than the serum acid soluble radioactivity until 60 min after injection. Liver and kidney acid soluble radioactivity was increased, but that of spleen, thymus and cerebrum was unaffected by partial hepatectomy. 6. 6. Sixty minutes after injection, the radioactivity in RNA was 1–10% of that in DNA per gram of spleen, thymus and regenerating liver, but 25 and 50 % of that in kidney and intact liver respectively. Incorporation of 3H-activity into liver RNA was increased 48 hr after partial hepatectomy; no difference was obtained in other organs. 7. 7. The main incorporation of 3H-thymidine into DNA was confined to the first 20 min after injection. The DNA radioactivity of the spleen was 2.3 %, thymus 0.4%, kidney 0.2% and that of intact liver 0.6 % of the total injected dose 60 min after injection. Forty-eight hours after partial hepatectomy the DNA radioactivity in the liver was 5 times that of control liver. At 24–72 hr after resection, incorporation of 3H-thymidine into DNA/g of liver was in the same range as that of thymus and spleen. The radioactivity of thymus and kidney DNA was reduced while that of liver DNA was at a maximum.

Early increase in diadenosine tetraphosphate in regenerating rat liver

Diadenosine tetraphosphate (Ap4A), a candidate for a signal molecule in the induction of DNA synthesis, was measured in regenerating livers of young adult rats at 12 and 24 h and of older rats at 24 h after partial hepatectomy. dATP and dTTP levels, which indicate the degree of proliferation in the livers, were determined by high-performance liquid chromatography and an enzymatic method, respectively. The Ap4A levels were increased in the beginning of DNA synthesis. In young rats the levels were about 140% of those of unoperated rats and in older rats about 300%. This increase was considerably smaller than that found in another study comprising two regenerating rat livers excised 20 h after partial hepatectomy, but still supports the hypothesis that Ap4A might take part in the onset of proliferation. The greater Ap4A increase in older rats may suggest a possible need for a stronger triggering mechanism to start proliferation in aged tissue. However, the experiments do not prove a function for Ap4A in the induction of DNA synthesis and it cannot be excluded that Ap4A is a product of an independent reaction.

Isotachophoretic and HPLC determination of nucleotides in rat liver cell nuclei isolated by non-aqueous technique

Rat liver whole cells and cell nuclei were prepared by a non-aqueous technique (glycerol). The nuclear preparations were of different purity as determined by RNA/DNA ratios (0.17-1.60) and accordingly were divided into 3 subgroups (mean values 0.29, 1.04 and 1.48). RNA nucleotides were separated by isotachophoresis and HPLC and calculated per mg DNA. Two of the nuclear subgroups (RNA/DNA = 1.04 and 1.48) had significantly elevated nucleotide values in relation to RNA/DNA. UDP-N-acetylhexosamine/DNA, on the contrary, was reduced in conformity with RNA in the preparations. Our findings may indicate different nucleotide concentrations in different parts of the cell.

Intracellular compartmentation of diadenosine tetraphosphate (Ap4A) and dTTP in rat liver

1. The intracellular compartmentation of diadenosine tetraphosphate (Ap4A) and of dTTP was studied in rat liver cells using non-aqueous glycerol for the isolation of cell nuclei. 2. This method allows a stepwise removal of cytoplasm from the nuclei. 3. The decrease in Ap4A or dTTP during the process was compared to the simultaneous decrease in RNA, which was taken to represent the cytoplasm. 4. In regenerating liver excised 24 hr after partial hepatectomy, Ap4A was almost equally distributed between the nucleus and cytoplasm. 5. In livers from unoperated control rats, the nuclear concentration of Ap4A was slightly elevated compared to that of whole cells. dTTP was only investigated in regenerating liver. 6. Significantly higher concentrations were found in the nuclear fractions. 7. The purest nuclei contained about 26% of whole cell levels of dTTP, while their RNA values had decreased to 7% of the whole cell RNA. 8. Considering that the liver cell nucleus comprises about 7% of the entire cell mass, a nuclear dTTP concentration of 26% indicates significantly higher dTTP levels in the nuclear compartment than in the cytoplasm of regenerating rat liver cells.

Factors influencing the serum activity in mice after intravenous and intraperitoneal injection of14C orotic acid

14C-Orotsäure wurde mit zwei verschiedenen Injektionsmethoden in Mäuse injiziert und die Serumaktivität nach 2, 5, 10, 20 und 60 min gemessen. Nach i.p. Injektion wurde Blut, das aus der Bauchhöle nach Entfernung der Leber entnommen worden war, mit noch nicht absorbiertem Isotop gemischt. Bei i.v. Schwanzinjektion verblieb bei nicht perfekter Injektion eine erhebliche Menge der Orotsäure im Schwanzgewebe und ergab einen kontinuierlichen Isotopenzuschuss zum Serum.

Serum and liver radioactivity levels in mice after intraperitoneal and subcutaneous injection of [14C]orotic acid

[14C]Orotic acid was rapidly distributed in blood after, both i.p. and s.c. injection but was not completely absorbed from the peritoneal cavity until 20 min after injection. S.c. injection should be an acceptable alternative to i.p. injection although the incorporation into the liver acid soluble- and RNA-fractions was somewhat delayed after the s.c. injection.

Variation of incorporation of [3H]orotic acid into the nucleotide and RNA fractions of different parts of the same liver lobe in the rat

1. Anaesthetized rats were given [3H]orotic acid either intraperitoneally or via a catheter into the hepatic artery with or without degradable starch microspheres. 2. The radioactivity in the acid soluble and RNA fractions of five pieces of the left lateral liver lobes was determined. 3. A variation of the distribution of the precursor into the different parts of the same liver lobe was shown. 4. This variation was most pronounced (3000-17,000 cpm/micrograms in the acid soluble fraction) when the precursor was administered via the artery and without microspheres. 5. The correlation between the radioactivity in the acid soluble and RNA fractions within each liver piece was 0.85, 0.90 and 0.75 in the three groups respectively. 6. It is suggested that the variation of the distribution depends on circulatory differences within the liver.