Sex-biased preferential care in the cooperatively breeding Arabian babbler

In many social birds there are sex differences in dispersal patterns, with males commonly remaining in their natal group whereas females typically disperse at adolescence. Group members may therefore increase their fitness by preferentially caring for offspring of a particular sex according to social circumstances. Although previous studies have focussed on intragroup social factors that may affect preferential care, we propose that the relative size of neighbouring groups is of primary importance. Here we show that in the cooperatively breeding Arabian babbler (Turdoides squamiceps), parents preferentially feed male offspring when relative group size is small, and female offspring when group size is large. Unlike parents, helpers consistently favour young of the opposite sex to themselves, suggesting the risk of competition with members of the same sex for future breeding opportunities may override other considerations. These results emphasize the complexity of investment strategies in relation to social circumstances and the variable benefits of raising males vs. females in a species with sex-biased philopatry.     

Food division in the Arabian babbler nest: adult choice or nestling competition?

Many studies have found that food division among nestmates isnegatively correlated with hatrhing order. The hypothesis thatfeedings are distributed according to the provisioners' selectionis compared here with the hypothesis that feedings are dividedas a consequence of nestling competition. Food distributionamong Arabian babbler nestmates was negatively correlated withhatching order and was so skewed that many last-hatched nestlingsdied as a consequence of starvation. No feeding preference wasfound between any adult and any given nestling. No differencewas found in feeding distribution among parents, partial parents,and nonparents. When an older foreign nestling was introducedinto the nest, adults fed the newcomer more intensively thantheir own offspring, implying that feeding division among nestmateswas not determined by die feeders but by the nestlings' relativeability to obtain food. In two-nestling nests, the older nestlingobtained 62% of the feedings, on average. However, followingselective feedings of the second-hatched nestling by the investigator,which equalized the two siblings' feeding amounts by the endof their second day, no difference was found between their feedingrates. The relative advantage of the older nestlings was eliminatedby introducing a barrier into the nest. Under these conditions,feedings were distributed equally among the nestmates. Sinceneither hatching order, previous priority order, nor individualidentification were used by the provisioning adults, the proximatefactor determining food division among the neslings appearsto be the result of nestling competition     

Minimal diurnal change in foraging time in an Australian passerine, the white-browed babbler Pomatostomus superciliosus

This paper describes the daily foraging pattern of the white-browed babbler Pomatostomus superciliosus , a small passerine endemic to Australia. The percentage of time spent foraging as the day progressed increased by an average of only 9%. This contrasts markedly with studies of other passerines that have mostly shown a bimodal pattern, with a peak of foraging early in the day followed by a period of reduced activity and a second peak later in the day. The most likely explanation for the observed pattern of foraging time is that babblers experienced considerable diurnal certainty in their food supply mainly as a result of stable and predictable weather conditions. The lack of a marked increase in foraging towards the end of the day might also have resulted from an increase in predation risk at this time and a reduced need to build up food reserves at the end of the day because of the energetic advantages of communal roosting in an enclosed nest.     

Ectopia cordis in the chick embryo heart: an experimental study

Ectopia cordis was observed during a study on the effects of a calcium antagonist (verapamil) on chicken embryo heart development. Experimental procedures, carried out at 60 hours of incubation, included placement of windows in eggs, injection of verapamil or saline, and the removal of ovalbumen from eggs. Fluid removal caused a downward displacement of the embryo and helped separate the embryo and its membranes from the shell membranes. Ectopia cordis was only observed in experiments involving fluid removal. One exception, the appearance of one ectopic heart in a window-only experiment (no fluid removed), remains unexplained. The movements of fluids, brought about by the withdrawal of ovalbumen from eggs, and the subsequent effects of such movements on the positioning of embryos seemed to be the most important factor in the genesis of ectopia cordis. Also observed in fluid removal experiments were asymmetric circulations, abnormal embryonic flexion, and several embryos whose positions were rotated. These abnormalities were probably related to fluid removal and/or ectopia cordis.     

Cryolumpectomy for breast cancer: an experimental study

The effects of cryosurgical procedures and surgical excision in preventing the local recurrence of mammary adenocarcinoma were studied in BALB/cfC3H mice carrying syngeneic, virus-induced mammary adenocarcinomas transplanted into the fourth mammary fat pad. In this report we present evidence demonstrating that cryosurgical procedures involving multiple freeze-thaw cycles followed by tumor excision markedly reduce the local recurrence rate of mouse mammary cancer. Surgical resection without cryotreatment resulted in an 80% local recurrence rate; in contrast, cryotreatment consisting of three freeze-thaw cycles before excision prevented local tumor recurrence in 70% of the animals. The use of cryotherapy and local excision (cryolumpectomy) in the treatment of human breast cancer is discussed.     

The temporalis myo-osseous flap: an experimental study

The present paper investigates the anatomy and vascularization of the temporalis myo-osseous flap. This is a calvarial bone flap that employs temporalis muscle and its distal pericranial extension as a pedicle. In six human cadavers the flap was raised as an island on the anterior deep temporal artery after transecting the zygomatic arch and coronoid process. Maximal mobilization was thus obtained, allowing rotation of the flap into the mouth for intraoral reconstruction. The arc of rotation and potential surgical applications were noted. A comparative study of the temporalis myo-osseous flap and free calvarial bone graft was then conducted in a rabbit model. Vascularization of the calvarial bone flap was confirmed by technetium scintigraphy performed on the first postoperative day. The uptake of fluorochrome labels immediately after transfer verified the adequacy of the periosteal circulation in maintaining viability and new osteoid formation throughout the full thickness of calvarial bone. The transplantation of free calvarial bone grafts was followed by necrosis of most cellular elements. This was demonstrated by an absence of fluorochrome uptake up to 19 days postoperatively and a predominance of empty lacunae and nonviable marrow.     

Adult-infant food transfer in common marmosets: an experimental study

Infant marmosets and tamarins obtain solid food items from adults during and after the time of weaning. In addition to providing nutrients, food transfers may provide infants with the opportunity to learn about diet. The aim of this study was to investigate patterns of begging and food transfer in captive groups of common marmosets during tests with 1) palatable novel food, 2) unpalatable novel food, and 3) familiar food. Infants may gain an opportunity to learn about diet breadth by preferentially begging for novel rather than familiar items, while adults may facilitate infant learning by differing in their willingness to transfer food depending upon the food's novelty or palatability. In this study, infants exhibited more interest and begging with novel food items than with familiar ones. However, food transfers were not more likely to occur with novel foods than with familiar ones, and in fact adults were more likely to refuse infant begging attempts with novel foods. The palatability of the food also did not influence the rates of refusal and transfer: adults transferred palatable and unpalatable novel foods with similar frequencies. These results suggest that infant marmosets gain an opportunity to learn about diet breadth by begging for novel foods, but adults do not preferentially transfer novel or palatable food items.     

Pathogenesis of restricted movements in trichinellosis: an experimental study

Trichinellosis is a zoonosis acquired by the ingestion of insufficiently cooked pork meat containing the encapsulated larvae of Trichinella spiralis. Trichinellosis is presented with myalgia which affects various muscle groups; its intensity is usually related to the severity of the disease and may cause restriction of joint movement. However, joint pain in the course of trichinellosis could not be explained entirely by myositis. This study investigated the other possible causes of restricted movements of joints in animal model. We found that the histopathological changes in the joints of T. spiralis infected rats were in the form of inflammatory cellular infiltrates and ulceration in the synovial membrane with degeneration and ulceration of the articular cartilage. Immunohistochemical examination of the joints revealed the presence of T. spiralis local antigen or immune complex deposited in the synovial membrane. Leukocytosis and eosinophilia were observed throughout the experimental period but eosinophil level declined slowly but still elevated. In conclusion, the restricted movements during the course of trichinellosis seem to be not only due to direct invasion of muscles by the encapsulated T. spiralis larvae but also due to immune complex deposition in the joints.     

Treatment options in extravasation injury: an experimental study in rats

Local skin necrosis after extravasation of doxorubicin hydrochloride (Adriamycin), a widely used chemotherapeutic agent, is a common problem in cancer patients. Even though several treatment options have been proposed for extravasation injury, there is still controversy regarding the management of such lesions. The aim of this study was to compare the efficacy of saline infiltration, vitamin C infiltration, suction technique, and early surgical excision as a treatment in a rat extravasation model. The authors planned their study in two stages. In stage 1, the lowest effective dose of doxorubicin at which a homogeneous skin necrosis was formed and the method of administration were investigated. Intradermal and subpannicular injections were made for six rats, using six different concentrations of doxorubicin (0.33, 0.5, 0.66, 1.0, 1.33, and 1.5 mg/ml). In stage 1, the intradermal injection produced homogeneous and uniform tissue necrosis. In stage 2, the efficacy of saline infiltration (group 1), vitamin C infiltration (group 2), suction (group 3), suction and saline washout (group 4), suction and vitamin C washout (group 5), and early surgical excision (group 6) was compared. The treatment options were applied 2 hours after doxorubicin injection. At the end of the seventh day, the presence and size of ulcers at the injection site were calculated. Fourteen days after injection, a histopathologic examination was performed for each treatment and control group. In groups 1 and 3, there was no statistically significant difference in the size of necrosis compared with the control groups. In groups 2, 4, and 5, the size of necrosis was smaller compared with the control groups, and this was statistically significant. Furthermore, in group 4 (suction and saline washout) and group 5 (suction and vitamin C washout), the calculated area of necrosis was smaller compared with other treatment groups, and this was statistically significant. The findings supported the assertion that suction and saline or vitamin C washout reduce necrotic tissue size in extravasation injury.     

Dissection properties of the human aortic media: an experimental study

Aortic dissection occurs frequently and is clinically challenging; the underlying mechanics remain unclear. The present study investigates the dissection properties of the media of 15 human abdominal aortas (AAs) by means of direct tension tests (n=8) and peeling tests (n=12). The direct tension test demonstrates the strength of the media in the radial direction, while the peeling test allows a steady-state investigation of the dissection propagation. To explore the development of irreversible microscopic changes during medial dissection, histological images (n=8) from four AAs at different peeling stages are prepared and analyzed. Direct tension tests of coin-shaped medial specimens result in a radial failure stress of 140.1+/-15.9 kPa (mean+/-SD, n=8). Peeling tests of rectangular-shaped medial strips along the circumferential and axial directions provide peeling force/width ratios of 22.9+/-2.9 mN/mm (n=5) and 34.8+/-15.5 mN/mm (n=7); the related dissection energies per reference area are 5.1+/-0.6 mJ/cm(2) and 7.6+/-2.7 mJ/cm(2), respectively. Although student's t-tests indicate that force/width values of both experimental tests are not significantly different (alpha=0.05, p=0.125), the strikingly higher resisting force/width obtained for the axial peeling tests is perhaps indicative of anisotropic dissection properties of the human aortic media. Peeling in the axial direction of the aorta generates a remarkably "rougher" dissection surface with respect to the surface generated by peeling in the circumferential direction. Histological analysis of the stressed specimens reveals that tissue damage spreads over approximately six to seven elastic laminae, which is about 15-18% of the thickness of the abdominal aortic media, which forms a pronounced cohesive zone at the dissection front.     

Macrophages: sentinels and regulators of the immune system

The important role of macrophages in host defense against a variety of pathogens has long been recognized and has been documented and reviewed in numerous publications. Recently, it has become clear that tissue macrophages are not entirely derived from monocytes, as has been assumed for a long time, but rather show an ontogenetic dichotomy in most tissues: while part of the tissue macrophages are derived from monocytes, a major subset is prenatally seeded from the yolk sac. The latter subset shows a remarkable longevity and is maintained by self‐renewal in the adult animal. This paradigm shift poses interesting questions: are these two macrophage subsets functionally equivalent cells that are recruited into the tissue at different development stages, or are both macrophage subsets discrete cell types with distinct functions, which have to exist side by side? Is the functional specialization that can be observed in most macrophages due to their lineage or due to their anatomical niche? This review will give an overview about what we know of macrophage ontogeny and will discuss the influence of the macrophage lineage and location on their functional specialization.