Habitat associations of breeding Meadow Pipits Anthus pratensis in the British uplands

Habitat associations of Meadow Pipits breeding in British upland 1 km and 10 km squares were investigated using data from the British Trust for Ornithology's (BTO) Breeding Bird Survey (BBS, 1994–97), The New Atlas of Breeding Birds in Britain and Ireland 1988–1991 and habitat data from the Institute of Terrestrial Ecology's (ITE) Land Cover Survey (1994). Meadow Pipit density was highest in 200 m sections of BBS 1 km transects containing unenclosed grass moor, heather and bog, but there was no difference in Meadow Pipit density between these habitat types. Meadow Pipit density (number of individuals per 1 km square) increased with heather cover up to about 7.5 200 m sections (of ten per 1 km square) of heather, but fell thereafter. There was a positive association between Meadow Pipit density and the extent of grass moor cover. The ITE Land Cover data gave results that were consistent with the BBS habitat data at both the 1 km and 10 km square scale. There was a non-linear relationship between hill grass cover and Meadow Pipit abundance, which reached a maximum when hill grass covered between 40%and 60% of a square. Our results suggest that a mosaic of heather, bog and grassland may be the optimum habitat for Meadow Pipits. Recent changes in land management practices may have led to the disappearance or degradation of these mosaics in some areas. Meadow Pipits are widespread and easily counted. We suggest that this species might be a useful bioindicator of changes in heather and grassland ratios that result from land management practices such as grazing and rotational burning, though further research is required.     

Regulation of creatine kinase induction in differentiating mouse myoblasts.

The regulation of creatine kinase (CK) induction during muscle differentiation was analyzed with MM14 mouse myoblasts. These cells withdraw from the cell cycle and commit to terminal differentiation when fed with mitogen-depleted medium. Myoblasts contained trace amounts of an isozyme of brain CK (designated BB-CK), but differentiation was accompanied by the induction of two other isozymes of muscle and brain CKs (designated MM-CK and MB-CK). Increased CK activity was detectable within 6 h of mitogen removal, 3 h after the first cells committed to differentiation and 6 h before fusion began. By 48 h, MM-CK activity increased more than 400-fold, MB-CK activity increased more than 150-fold, and BB-CK activity increased more than 10-fold. Antibodies prepared against purified mouse MM-CK cross-reacted with muscle and brain CKs (designated M-CK and B-CK, respectively) from a variety of species and were used to demonstrate that the increase in enzymatic activity was paralleled by an increase in the protein itself. CK antibodies were also used to aid in identifying cDNA clones to M-CK. cDNA sequences which corresponded to protein-coding regions cross-hybridized with B-CK mRNA; however, a subclone containing the 3'-nontranslated region was unique and was used to quantitate M-CK mRNA levels during myoblast differentiation. M-CK mRNA was not detectable in myoblasts, but within 5 to 6 h of mitogen withdrawal (6 to 7 h before fusion begins) it accumulated to about 30 molecules per cell. By 24 h, myotubes contained approximately 1,100 molecules per nucleus of M-CK mRNA.     

Comparison of haemodynamic responses to dobutamine and salbutamol in cardiogenic shock after acute myocardial infarction.

Nine patients with critically reduced cardiac output after acute myocardial infarction underwent a single cross-over comparison of dobutamine and salbutamol to compare the haemodynamic effects of these drugs, which have, respectively, predominantly beta 1-adrenergic and beta 2-adrenergic agonist activity. The responses were used to select the more appropriate treatment for individual patients. Only relatively small responses were obtained: those with poorest baseline measurements tended to show the least effect. When the results from the series were averaged, dobutamine (250-750 microgram/min) caused a small but progressive increase in cardiac index (1.8 to 2.2 1/min/m2) throughout the dose range. Systemic blood pressure was not increased, and calculated systemic vascular resistance fell from 25 to 19 units. Heart rate rose from 107 to 118 beats/min and stroke index from 17 to 19 ml/beat/m2. Pulmonary artery end-diastolic pressure fell from 18 to 15 mm Hg. Salbutamol (10-40 microgram/min) produced a similar progressive increase in cardiac index, from 1.6 to 2.21/min/m2. Systemic blood pressure was not altered, and systemic vascular resistance fell from 25 to 20 units. Heart rate rose from 105 to 119 beats/min and stroke index from 16 to 19 ml/beat/m2. Pulmonary artery end-diastolic pressure did not fall. Dobutamine and salbutamol have closely similar haemodynamic effects when used in cardiogenic shock after acute myocardial infarction. Both drugs increase cardiac index but heart rate also rises, and the increase in stroke index is relatively small. Mean arterial pressure is altered little by either agent, but dobutamine (in contrast with dopamine) tends to reduce pulmonary artery end-diastolic pressure, which may be beneficial.     

The House Sparrow Passer domesticus in urban areas: reviewing a possible link between post-decline distribution and human socioeconomic status

The House Sparrow Passer domesticus is traditionally associated with human habitation. However, the species has undergone dramatic declines in many urban areas in north-western Europe. There are many theories as to why this decline has occurred, but the lack of data on House Sparrow numbers prior to their decline has hampered efforts to investigate these theories in detail. This review summarises the demographic changes in urban House Sparrow populations since the 1970s, and considers evidence that the current distribution of House Sparrows may reflect changes in urban habitats caused by socioeconomic change. Evidence is mounting that, within urban landscapes, House Sparrows appear to be more prevalent in areas with a relatively low human socioeconomic status. Here, we present evidence to suggest that House Sparrows may have disappeared predominantly from more affluent areas, and that these areas are more likely to have undergone changes to habitat structure. We also show how these changes in habitat could influence House Sparrow populations via impacts upon nesting success, foraging and predation risk.