Human impact and population dynamics in the Neolithic and Bronze Age: Multi-proxy evidence from north-western Central Europe

This paper aims at reconstructing the population dynamics during the Neolithic and Bronze Age, c. 4500–500 cal. BC, in north-western Central Europe. The approach is based on the assumption that increased population density is positively linked with human activity and human impact on the environment, respectively. Therefore, we use archaeological 14C dates and palaeoenvironmental data from northern Germany and south-western Denmark to construct and compare independent proxies of human activity. The latter involves relative quantification of human impact based on pollen analysis and soil erosion history inferred from summarizing of dated colluvial layers. Concurring patterns of changes in human activity are frequently recorded on a multi-centennial scale. Whereas such multi-proxy patterns are interpreted to indicate relative population changes, divergent patterns are discussed in the context of proxy-related uncertainties and potential biases. Patterns of temporal distribution of increasing and decreasing human activity are understood as ‘boom and bust’ phases in population density/size. Based on the comparison of the three proxies, we identify five phases of growing (boom) and four phases of decreasing (bust) population. The boom phases date to ca. 4000–3500, 3000–2900, 2200–2100, 1450–1300 and 1000–750 cal. BC. The bust phases to ca. 3200–3000, 2400–2300, 1650–1500 and 1200–1100 cal. BC

Viability and ICAM-1 expression on murine endothelial cells is unaffected by CB₂ receptor signaling.

<p>A, Murine EC isolated from LDLR^−/− mice were stimulated with or without TNFα (20 ng/ml) and JWH-133 (4 µM and 40 µM, N = 4). In parallel, experiments, EC isolated from CB₂^−/−/LDLR^−/− mice and CB₂^+/+/LDLR^−/− control animals were stimulated with or without TNFα (20 ng/ml, N = 6). Cell lysates were analyzed for ICAM-1 by Western blotting. Western blots were analyzed densitometrically and adjusted for GAP-DH. Pooled data are given as mean ± SEM and representative blots are shown. B, Similarly, Murine EC isolated from wild-type mice where stimulated with indicated concentrations of JWH-133 and with or without TNFα (20 ng/ml). The cells were then analyzed for ICAM-1 expression using flow cytometric assays. Data is shown as mean ± SEM (N = 6). Asterisks indicate significant change, defined as p<0,05. C, In supernatants of EC treated as described above MCP-1 was quantified by ELISA. Data is shown as mean ± SEM. D and E, Murine EC isolated from wild-type mice were stimulated with indicated concentrations of JWH-133 and then the rate of apoptosis was determined using the Apo-ONE® Assay (D). Data is shown as the mean ± SEM (N = 5). The supernatant of cells treated in a similar manner were used to examine cytotoxicity with the CytoTox-ONE™ Assay (E). Data is shown as the percent of control (N = 6).</p

Inflammatory cell recruitment is differentially affected by CB₂ receptor stimulation.

<p>A, Wild-type mice received intraperitoneal injections of 4% thioglycollate after pre-treatment with JWH-133 or vehicle control. Leukocyte recruitment into the peritoneal cavity was quantified after 72 and 4 h. Data represent mean ± SEM. Asterisks indicate significant change, defined as p<0,05. B, In parallel, thioglycollate-elicited accumulation of leukocytes in the peritoneal cavity was quantified in CB₂^−/−/LDLR^−/− mice and CB₂^+/+/LDLR^−/− control animals. Data for both 72 and 4 h stimulation are expressed as mean ± SEM. C, PMA-activated thioglycollate-elicited peritoneal leukocytes obtained from wild-type (Bl6) mice were allowed to adhere on TNFα-activated endothelial cells (EC) isolated by magnetic bead separation from wild-type mice in the presence or absence of 40 µM JWH-133. Adhering leukocytes were quantified under microscope after the indicated time points in the flow chamber (N = 3 each). In parallel experiments PMA-activated thioglycollate-elicited peritoneal leukocytes from CB₂^−/−/LDLR^−/− mice were allowed to adhere on TNFα-activated EC isolated from CB₂^−/−/LDLR^−/− mice. Adhesion was quantified and compared with the interaction of peritoneal leukocytes and EC isolated from CB₂^+/+/LDLR^−/− (N = 5 each). Pooled data represent mean ± SEM.</p

Characteristics of study animals before and after feeding.

<p>Characteristics of study animals before and after feeding.</p

Treatment with the CB₂ agonist JWH-133 does not modulate atherosclerosis in mice.

<p>A and B, LDLR^−/− mice consuming high cholesterol diet for 16 weeks (HCD) received intraperitoneal injections of 5 mg/kg JWH-133 (N = 10) or vehicle control (Tocris, N = 8) three times a week. Intimal lesion area in the aortic root (A) and arch (B) are diplayed as pooled data ± SEM; representative images stained for lipid deposition (Oil-red-O) are shown below the corresponding graph. C, The abdominal aortas of mice treated as described above underwent <i>en face</i> analysis of lipid deposition. Oil-red-O-positive staining in relation to total wall area was quantified and is displayed as pooled data ± SEM (N = 8 and 10); representative images are shown below. D, Sections of aortic roots of mice treated as described above were analyzed for lipid-, macrophage-, collagen-, T cell-, smooth muscle cell- and apoptotic cell content. Oil-red-O-, Mac-3-, picosirius red-, CD4-, α-actin- and TUNEL-positive staining in relation to total wall area is given as mean ± SEM (N = 8 and 10).</p