Goshawk prey have more bacteria than non-prey.

1. Predators often prey on individuals that are sick or otherwise weakened. Although previous studies have shown higher abundance of parasites in prey, whether prey have elevated loads of micro-organisms remains to be determined. 2. We quantified the abundance of bacteria and fungi on feathers of woodpigeons Columba palumbus L., jays Garrulus glandarius L. and blackbirds Turdus merula L. that either fell prey to goshawks Accipiter gentilis L. or were not depredated. 3. We found an almost three-fold increase in bacterial load of prey compared with non-prey, while there was no significant difference between prey and non-prey in level of fungal infection of the plumage. 4. The results were not confounded by differences in size or mass of feathers, date of collection of feathers, or date of analysis of feathers for micro-organisms. 5. These findings suggest a previously unknown contribution of bacteria to risk of predation, with important implications for behaviour, population ecology and community ecology.

Climate change affects the duration of the reproductive season in birds.

1. The duration of the reproductive season may depend on the duration of the growing season, with recent amelioration in spring temperatures allowing earlier start of reproduction. Earlier start of reproduction may allow a longer breeding season because of more broods a longer interval between broods for multi-brooded species. 2. We analysed extensive long-term data sets on timing of breeding in 20 species of birds from Denmark, based on records of over 100 000 individual offspring, showing considerable heterogeneity among species in temporal change in duration of the breeding season. 3. Multi-brooded species increased the duration of their breeding season by 0.43 days year(-1) while single-brooded species decreased the duration of their breeding season by 0.44 days year(-1). This implies that recent climate change has allowed more broods or better temporal spacing of broods in multi-brooded species, while the time window for reproduction has become narrower in single-brooded species. 4. The single-most important predictor of change in duration of the breeding season was change in the date breeding started; there was no change in the date of end of breeding. Species advancing their breeding date the most also expanded the duration of the breeding season. In contrast, long-distance migration and generation time did not predict change in duration of the breeding season.

Viability selection on prey morphology by a generalist predator.

Prey use their locomotory capacity to escape predators, and there should thus be strong viability selection on locomotory morphology of prey. We compared feather morphology of wood pigeons Columba palumbus killed by goshawks Accipiter gentilis with that of survivors to quantify directional and quadratic selection on primary and rectrix feathers. The goshawk is mainly a predator attacking by surprise, leaving wood pigeons with an ability to accelerate fast at a selective advantage. There was directional selection for light primary feathers with a narrow calamus. In addition, there was directional selection for increased area of rectrices. These patterns of natural selection were confirmed in multivariate analyses of selection that showed selection for light primary feathers with a large area and narrow calamus and for a large area of rectrix feathers. These results provide evidence of selection on different aspects of feather morphology directly related to flight performance and thus escape ability from predators.

Marginal evidence for cosmic acceleration from Type Ia supernovae.

The 'standard' model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present - as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these 'standardisable candles' indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.

Variation in the number of genes coding for salivary amylase in the bank vole, clethrionomys glareola.

A Danish population of bank voles is polymorphic for three electrophoretically different salivary amylases; A, H and S, of which A is the most common. Both single-, double- and triple banded phenotypes were observed, and in several crosses two electrophoretic forms cosegregated. In addition to the qualitative variation, some individuals show consistent quantitative variation in the relative activities of their amylase bands. This variation has been qualified by spectrophotometrical measurements of the relative amounts of amylase protein in the various bands. --Seventy wild chromosomes were analyzed by determining the amounts of amylase they produced when heterozygous with a laboratory stock chromosome known to carry two closely linked amylase genes, both coding for a fourth electrophoretic variant, B. The amount of A-protein divided by half the amount of B-protein was used as an estimate of the number of A-genes on the tested chromosomes. The wild chromosomes fell into three clearly distinguishable classes: 9 clustered around a gene number estimate of one, 45 chromosomes yielded estimates around two genes, and the gene number estimate of the remaining 16 was close to three. The integer values of the gene number estimates and the cosegregation of electrophoretically different salivary amylases are consistent with the model that the population is polymorphic for chromosomes with either one, two, or three closely linked amylase genes. It is suggested that such gene number variation may be more common than generally recognized, and some other reported cases of quantitative enzyme variation, for instance that of human red cell acid phosphatase, are interpreted in terms of variation in the number of genes involved.

Variation in amylase haplotypes among congenic lines of the house mouse.

Pancreatic amylase in the mouse displays considerable quantitative genetic variation. Agar gel electrophoresis reveals that homozygous animals have either one form of the enzyme, type A, or two forms, type AB. Only few animals have been found that contradict this statement, namely among Mus musculus castaneous from Thailand, which has a single-banded B type. Double-banded homozygous specimens of various origins have different relative proportions of the two isoenzymes. By measuring the A:B ratios in such animals, a number of distinct haplotypes or amylase complexes, determining ratios ranging from 61% A:39%, B to 12% A:88% B, have been recognized. These complexes differ also with respect to the total amount of amylase produced. If the reference stock C3H/As is given the value 1, then other haplotypes have values ranging from 1.0 to 0.27. Nineteen amylase haplotypes have been established in congenic lines on a C3H/As background. Some of these lines contain at least four active pancreatic amylase structural genes and breeding experiments have demonstrated that the genetic elements regulating total amylase production and relative proportions of the isoenzymes are located within the amylase complex, cis-acting, and very closely linked to the structural genes.

Electrophoretic variation for x-chromosome-linked phosphoglycerate kinase (pgk-1) in the mouse.

Electrophoretic variation for X-chromosome-linked phosphoglycerate kinase (PGK-1) has been found as a polymorphism in feral mice in Denmark. Males from feral sampling or from a variety of genetic crosses have only a single-banded phenotype of the variant PGK-1A type or of the PGK-1B type commonly found among inbred mice. By contrast, three phenotypes were observed among females; two homozygous single-banded types and a heterozygous double-banded type. The X-chromosome linkage of the Pgk-1 locus was determined from the mode of inheritance in F(1) and backcross generations and confirmed by the linkage of Pgk-1 and the X-linked markers Hq, Ta and Mo. Pgk-1 showed 29/122 recombinations with Hq, 5/185 with Ta and 0/108 recombinants with Mo. Based on these recombination data, a gene order of Hq-Ta-Pgk-1-Mo is suggested.

Genetic variation in amount of salivary amylase in the bank vole, Clethrionomys glareola.

Several investigated bank vole populations are polymorphis for the number of salivary amylase loci, and individual chromosomes may carry one, two or three linked amylase structural genes. In the present study, we have used bank vole stocks homozygous for different chromosomes to investigate the relationship between amylase production and gene number. By measuring the amylase activity in parotid glands and the percentage of amylase protein in saliva, we have been able to demonstrate that the amount of salivary amylase is directly proportional to the proposed gene number. The paper also describes the allele, AmySu, which codes for a heat-labile salivary amylase. The relative amounts of the heat-labile isozyme have been determined in different heterozygotes containing this allele, and these results also support the multiple locus model. Finally, a stock devoid of salivary amylase activity was established. Animals from this strain have, however, a protein in the parotid glands and in saliva that is very similar to amylase in molecular weight, amino acid composition and in its binding to glycogen and cyclohepta-amylose. In genetic crosses, the protein segregates as an amylase allele. Therefore, this protein, encoded by the functionally null allele AmyN, may represent an incorrectly processed amylase precursor.

Renal handling of carboplatin.

The mechanism for renal handling of carboplatin was studied in 17 ovarian cancer patients treated with a combination of carboplatin and cyclophosphamide. Carboplatin and [51Cr]-ethylenediaminetetraacetic acid (EDTA) renal clearances were measured simultaneously during short intervals of from 45 to 120 min. A total of 131 clearance intervals were analyzed during 35 chemotherapy courses. The carboplatin/[51Cr]-EDTA clearance ratio (R) served as an indicator of the net tubular reabsorption (R less than 1) or secretion (R greater than 1). The R value was calculated for each sampling interval. No significant difference was found between interpatient and intertreatment variation. The intertreatment variation as tested against the variation in the short intervals by an F-test was highly significant. We calculated the average R value for each treatment and consequently based our results on a total of 35 observations. The mean R value was 0.77 (t-test for R = 1; P less than 0.001). We conclude that the renal elimination of carboplatin takes place by glomerular filtration followed by tubular reabsorption.

Location of adrenal medullary pheochromocytoma by I-123 metaiodobenzylguanidine SPECT.

This is a retrospective study evaluating the efficacy of SPECT in the location of pheochromocytoma. Thirty patients with a suspected pheochromocytoma underwent I-123 metaiodobenzylguanidine (I-123 MIBG) SPECT 4 and 22 hours after intravenous injection of 370 MBq I-123 MIBG. SPECT was compared with planar scintigraphy, CT scanning, histology, and clinical course. Twenty-two-hour I-123 MIBG SPECT correctly identified 10 patients with adrenal medullary pheochromocytoma and correctly excluded pheochromocytoma in 19 patients. The sensitivity of the 22-hour MIBG SPECT was 1.00 and the specificity was 0.95. The positive predictive value was 0.95 and the negative predictive value was 1.00. In 16 patients, planar scintigraphy was compared with SPECT. SPECT located normal adrenal glands and tumors with greater confidence in three dimensions, but the patients with adrenal medullary pheochromocytoma were all correctly identified by planar scintigraphy. The results of SPECT and CT agreed in 29 of 30 patients (96.7%). I-123 MIBG SPECT for the location of pheochromocytoma has a high sensitivity, specificity, and positive and negative predictive values. I-123 MIBG SPECT or CT scanning alone were equally good for locating adrenal medullary pheochromocytoma but the combination of MIBG SPECT and CT makes it possible to distinguish between functioning and nonfunctioning adenomas. I-123 MIBG SPECT may be used alone or in combination with planar scintigraphy when three-dimensional location of a lesion is wanted.

[Study of children with urinary tract infections. Does intravenous urography play any role?]. / Udredning af børn med urinvejsinfektion. Spiller intravenøs urografi stadig en rolle?

Ninety children referred to hospital with urinary tract infections (UTI) were investigated by intravenous urography (IVU), ultrasonography (US) and 99m-Tc dimercaptosuccinic acid scan (DMSA). Fifty-eight children also had a micturition cystourethrography performed. In 36 (40%) of the children at least one result was abnormal. In 29 children IVU was abnormal, 10 had abnormal US and 16 had abnormal DMSA. Six of the 58 children had vesicoureteric reflux in eight kidneys. In 16 children IVU was the only examination with an abnormal result, and in ten of these the findings were considered important for treatment or prognosis. In conclusion, IVU is an important supplement to US and DMSA in investigation programs for children with UTI. IVU should be performed in cases of renal scarring or dilatation and in children with recurrent infections.

Basolateral endocytosis of protein in isolated perfused proximal tubules.

Luminal uptake and degradation of protein in proximal tubules is well documented. However, abluminal uptake has only been demonstrated in a few species and probably only amounts to a few percent of luminal absorption. To investigate this absorptive pathway, isolated perfused proximal tubules from rabbit kidney were exposed to either cationized ferritin or horseradish peroxidase in the bath for 30 min. The tubules were then fixed and processed for electron microscopy. Peroxidase and small amounts of ferritin were found in the intercellular spaces, in endocytic vesicles located in the abluminal part of the cells and in multivesicular bodies. No tracer was found in the lumina or in the apical part of the cells. The tubules were ultrastructurally intact thus excluding the possibility that the proteins were absorbed via the luminal endocytic pathway or as a result of damaged cell membranes. In conclusion, this study presents evidence that ferritin and peroxidase can be absorbed via the basolateral membranes in rabbit proximal tubules.

Nervous connections between the brain and the pineal gland in the cat (Felis catus) and the monkey (Cercopithecus aethiops).

Silver-impregnated series of cat and monkey (Cercopithecus aethiops) brains were studied in an attempt to demonstrate the existence of nervous connections between the brain and the pineal gland via the pineal stalk (central pineal connections). The presence of such connections between both the pineal gland and the habenular area, and between the pineal gland and the posterior commissure was verified in this study. A well defined median nerve tract between the pineal gland and the posterior commissure is described.

Innervation of the pineal gland in the mongolian gerbil (Meriones unguiculatus). A fluorescence microscopical study.

The innervation of the pineal gland in the Mongolian gerbil, Meriones unguiculatus, was investigated light microscopically by the Falck-Hillarp fluorescence technique and by conventional light microscopy. The pineal gland displayed a superficial portion just beneath the confluens sinuum and a deep part (lamina intercalaris) connected by a slender pineal stalk, which contained pinealocytes. The superficial part of the pineal gland consisted of dark-stained pinealocytes arranged in lobules, and separated by interstitial cells and connective tissue spaces. Many larger chromophobe cells were scattered throughout this region. A heavy catecholaminergic innervation of the superficial portion of the pineal organ, probably via the conarian nerve, with green fluorescent nerve fibres showing excitation/emission maxima of 415/475 nm was observed. Green fluorescent nerve fibres were also observed in the pineal stalk, from where some fibres turned rostrally indicating a nervous connection between the brain and the pineal organ. The pinealocytes showed a yellow fluorescence displaying a broad excitation curve with a maximum of 380-430 nm and an emission maximum at 505 nm. This indicates the presence of both serotonin and a catecholamine in the pinealocytes. Yellow fluorescence of the cells in the lamina intercalaris was also observed.

Influence of flow rate and perfused load on insulin absorption in isolated proximal tubules.

The effect of flow rate and perfused load on insulin absorption was studied in isolated proximal rabbit tubules. In one series of experiments tubules were perfused for 30 min with 125I-[A14]insulin at 3.6 ng/ml and at flow rates varying between 2.2 and 43.3 nl/min, thus varying both flow rate and the perfused load. In a second series of experiments the tubules were exposed to increasing loads of insulin at a fixed flow rate of 15 nl/min. In a third series of experiments two groups of tubules were exposed to identical perfused loads at two different flow rates. The results showed that absorption is linearly correlated with the perfused load in the ranges of flow rates and concentrations examined. The perfused load determined the magnitude by which the insulin was reabsorbed, whereas the flow rate determined the efficiency (fractional absorption) by which the protein was reabsorbed. At flow rates less than 5 nl/min the fractional absorption was greater than 65%, and at flow rates greater than 30 nl/min fractional absorption was less than 40%. Thus, there is an inverse relationship between flow rate and fractional absorption. The described effects of changes in flow rate and perfused load are suggested to be caused by concomitant changes in the mean luminal concentration.

Ultrastructure of isolated perfused proximal tubules from rabbit kidney. A comparison with proximal tubules fixed by perfusion in vivo.

This study was carried out to determine whether the ultrastructure of proximal tubules isolated and perfused in vitro was comparable to the ultrastructure of tubules fixed by perfusion in vivo. The kidneys of female white rabbits were either fixed by perfusion in vivo with glutaraldehyde (controls) or removed for dissection (experimentals) of proximal convoluted tubules and late proximal straight tubules. The isolated tubules were perfused in vitro with Krebs-Ringers bicarbonate solution for 1 hour after which the tubules were fixed with glutaraldehyde. The experimental tubules and the control tubules were processed for electron microscopy, compared qualitatively, and analyzed morphometrically to evaluate the volume densities and surface densities of different cell organelles and the cell membrane. Qualitatively, there were no differences in the appearance of cell organelles in experimental tubules and control tubules, except that cells in some experimental tubules accumulated small lipid droplets which were located close to mitochondria. Only a few quantitative changes were found, the most noteworthy being a 40% decreased surface density of the brush border in experimental proximal convoluted tubules and late proximal straight tubules. Damaged experimental tubules showed an increased number of vacuoles in the inverted microscope. In the electron microscope the vacuoles corresponded to swollen and disintegrated mitochondria and enlarged endocytic vacuoles. However, small degrees of tubular damage were not observable in the inverted microscope, as very small vacuoles could only be seen in the electron microscope. The results show that proximal tubules can be dissected and perfused in vitro for 1 hour without major ultrastructural changes. It should be emphasized that tubules showing an increased vacuolization in the inverted microscope may be damaged and, thus, not function optimally, and even if the tubules appear undamaged in the light microscope they may show signs of cellular degeneration in the electron microscope.

Genetic variation in restriction patterns among mouse amylase gene complexes.

The expression of pancreatic amylase in the mouse exhibits pronounced genetic variation. Congenic lines with various amylase complexes on a common C3H/As background have different numbers and forms of isoenzymes. The relative ratio of these isoenzymes may vary, as does the overall production of pancreatic amylase, which in some lines is three- to fourfold higher than in others. DNA from a number of lines was digested with endonucleases and hybridized to an amylase cDNA probe. The restriction patterns from inbred stocks and the corresponding congenic lines are identical, demonstrating that the majority of (if not all) amylase-like DNA sequences is found within the amylase complex. Congenic lines with specific amylase expression, for instance, in enzyme production, show different restriction patterns, whereas three lines with the same amylase phenotype have a uniform pattern. Most of the variation in amylase expression is represented among congenic lines derived from Danish mice. A comparison of such lines with others of remote geographic origin reveals that the restriction patterns of the "Danish" lines have by far the highest degree of resemblance. This observation seems to exclude major rearrangements within the amylase complex as the cause of the differences in enzyme expression, which instead are likely to be due to variation in regulatory elements associated with the active structural amylase genes in the complex.

Transtubular transport of proteins in rabbit proximal tubules.

The purpose of the present experiments was to study possible different pathways of intracellular transport of proteins after luminal and basolateral uptake in isolated rabbit proximal tubules. Tubules were exposed to cationized ferritin (CF) in the perfusion fluid and horseradish peroxidase (HRP) in the bath simultaneously or to HRP in the bath alone for 30 min. The peritubular fluid (bath) and perfusion fluid were then exchanged and the tubules either fixed immediately or allowed to function during chase-periods for 10, 20, 30, or 60 min before fixation to follow the migration of the proteins through the cells. The proteins were to a large extent found separated in different vacuoles and lysosomes at all time periods studied, indicating separate pathways after uptake via the luminal and basolateral membranes respectively. About 0.5% of the CF taken up by the cells was transported through the cells and became located in the intercellular spaces. HRP was transported from the peritubular fluid to the apical cytoplasm of the tubules indicated by a gradual accumulation of small HRP-containing vesicles, first in the basal part of the cells and then in the apical cytoplasm. In tubules perfused with both CF and HRP in the perfusate, the CF and HRP were found together in apical vacuoles and lysosomes. After perfusion with HRP alone, this tracer was found in similar large vacuoles and lysosomes in the apical cytoplasm, in contrast to the small HRP-filled vacuoles seen after uptake from the bath.