Volumetric hand‐held optoacoustic angiography as a tool for real‐time screening of dense breast

Existing mammographic screening solutions are generally associated with several major drawbacks, such as exposure to ionizing radiation or insufficient sensitivity in younger populations with radiographically‐dense breast. Even when combined with ultrasound or magnetic resonance imaging, X‐Ray mammography may still attain unspecific or false positive results. Thus, development of new breast imaging tools represents a timely medical challenge. We report on a new approach to high‐resolution functional and anatomical breast angiography using volumetric hand‐held optoacoustic tomography, which employs light intensities safe for human use. Experiments in young healthy volunteers with fibroglandular‐dominated dense breasts revealed the feasibility of rendering three‐dimensional images representing vascular anatomy and functional blood oxygenation parameters at video rate. Sufficient contrast was achieved at depths beyond 2 cm within dense breasts without compromising the real‐time imaging performance. The suggested solution may thus find applicability as a standalone or supplemental screening tool for early detection and follow‐up of carcinomas in radiographically‐dense breasts.

Volumetric handheld optoacoustic tomography scanner uses safe pulses of near‐infrared light to render three‐dimensional images of deep vascular anatomy, blood oxygenation and breast parenchyma at video rate.     

Propensity Scoring after Multiple Imputation in a Retrospective Study on Adjuvant Radiation Therapy in Lymph-Node Positive Vulvar Cancer

Propensity scoring (PS) is an established tool to account for measured confounding in non-randomized studies. These methods are sensitive to missing values, which are a common problem in observational data. The combination of multiple imputation of missing values and different propensity scoring techniques is addressed in this work. For a sample of lymph node-positive vulvar cancer patients, we re-analyze associations between the application of radiotherapy and disease-related and non-related survival. Inverse-probability-of-treatment-weighting (IPTW) and PS stratification are applied after multiple imputation by chained equation (MICE). Methodological issues are described in detail. Interpretation of the results and methodological limitations are discussed.     

Identification and characterization of 10 polymorphic microsatellite loci in the German cockroach,Blattella germanica

Primer sequences and initial characterization are presented for 10 microsatellite loci isolated from the German cockroach, Blattella germanica. In a sample of 30 individuals from a single population sample, all loci were polymorphic with two to 12 alleles segregating per locus and levels of observed heterozygosity ranging from 0.27 to 0.92. One locus showed a deficit of heterozygotes. Experimental conditions are described for polymerase chain reaction multiplexing, which enables the genotyping of eight loci in three electrophoretic runs consisting of one set of three and two sets of two markers. Seven primer sets cross‐amplify in the related Blattella asahinai.     

Interferon-alpha acutely impairs sleep in healthy humans

We investigated the effects of two low doses of interferon-alpha (IFN-alpha) on nocturnal sleep in 18 healthy men by means of polysomnographic sleep recordings. At 1900h, human recombinant IFN-alpha (1000 or 10000 U/kg body weight) or placebo was administered subcutaneously. Between 2300h and 0700h subjects were allowed to sleep. In general effects were stronger at the dose of 10000 than 1000 U/kg body weight of IFN-alpha. Although, after IFN-alpha subjects experienced increased fatigue, the cytokine impaired the quality of nocturnal sleep. The higher dose of IFN-alpha suppressed slow wave sleep (17.8 +/- 2.0% vs 25.2 +/- 2.6% following placebo, P<0.003) but increased time spent in shallow sleep (P<0.05) during the first half of sleep time. Rapid eye movement (REM) sleep latency was postponed (P<0.02) and time spent in REM sleep was significantly decreased after IFN-alpha (P<0.04). The impairing influence of IFN-alpha on sleep in humans is in contrast with findings of sleep promoting effects of this cytokine in animals. Our data suggest that endogenous IFN-alpha may be a factor responsible for alterations of sleep, e.g. in the course of viral infections.     

Unusual presentation of hypophysitis preceding an empty sella in a 75-year-old woman

A 75-year-old woman complained about progressing fatigue. She appeared somnolent, but fully oriented and in no acute distress. Her face was pale and puffy. She did not show any signs of focal neurological disease, and the remainder of the physical examination was unrevealing. Routine laboratory tests were unremarkable except for hyponatremia and mildly decreased levels of free T3 and free T4, with TSH in the normal range. Pituitary function tests demonstrated secondary adrenal insufficiency and hypothyroidism. Magnetic resonance imaging (MRI) unmasked hypophysitis with the characteristic findings of homogeneous gadolinium uptake of the pituitary and a prominent pituitary stalk ('dural tail sign', arrows in Fig. 1 A and B, sagittal and coronal views). Substitution of hydrocortisone and levothyroxine resulted in rapid and sustained improvement of all symptoms and normalisation of laboratory findings. MRI abnormalities normalized within the following six months. At follow-up three years later, MRI signs had further regressed and demonstrated an empty sella (Fig. 2 A and B).     

Reshaping of sandstone surfaces by cryptoendolithic cyanobacteria: bioalkalization causes chemical weathering in arid landscapes

We report a novel weathering mechanism in South African sandstone formations, where cryptoendolithic cyanobacteria induce weathering by substrate alkalization during photosynthesis. As a result, the upper rock part is loosened and then eroded away by physical forces such as wind, water, trampling. This special type of ‘exfoliation’ is widely distributed and affects the geomorphology of whole sandstone mountain ranges and outcrops across several biomes. We show, that this weathering type is initiated by bioalkalization because of the photosynthesis of cryptoendolithic (i.e. those organisms living in small tight open spaces between the sand grains) cyanobacteria causing pH values high enough to enhance silica solution in the cryptoendolithic zone. As modern cyanobacteria are the initial photoautotrophic colonizers of bare rocks in arid and semiarid landscapes, it is possible that they may also have played a significant role in shaping sandstone landscapes in the geological past.     

Linear and threshold-dependent expression of secondary sexual traits in the same individual: insights from a horned beetle (Coleoptera: Scarabaeidae)

Elaborate horns or horn‐like structures in male scarab beetles commonly scale with body size either (a) in a linear fashion with horn size increasing relatively faster than body size or (b) in a threshold‐dependent, sigmoid fashion; that is, males smaller than a certain critical body size develop no or only rudimentary horns, whereas males larger than the threshold size express fully developed horns. The development of linear vs. sigmoid scaling relationships is thought to require fundamentally different regulatory mechanisms. Here we show that such disparate regulatory mechanisms may co‐occur in the same individual. Large males of the south‐east Asian Onthophagus (Proagoderus) watanabei (Ochi & Kon) (Scarabaeidae, Onthophagini) develop a pair of long, curved head horns as well as a single thoracic horn. We show that unlike paired head horns in a large number of Onthophagus species, in O. watanabei the relationship between head horns and body size is best explained by a linear model. Large males develop disproportionately longer horns than small males, but the difference in relative horn sizes across the range of body sizes is small compared to other Onthophagus species. However, the scaling relationship between the thoracic horn and body size is best explained by a strongly sigmoid model. Only males above a certain body size threshold express a thoracic horn and males smaller than this threshold express no horn at all. We found a significant positive correlation between head and thoracic horn length residuals, contrary to what would be expected if a resource allocation tradeoff during larval development would influence the length of both horn types. Our results suggest that the scaling relationship between body size and horn length, and the developmental regulation underlying these scaling relationships, may be quite different for different horns, even though these horns may develop in the same individual. We discuss our results in the context of the developmental biology of secondary sexual traits in beetles. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83 , 473–480.