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At least 595 records · Page 33Linked to original sources
PubMed2005

Unilateral frontalis sling for the surgical correction of unilateral poor-function ptosis.

PURPOSE: To evaluate the functional and cosmetic results after frontalis sling repair for unilateral ptosis associated with either poor levator function or synkinesis. METHODS: Preoperative and postoperative photographs and records of 127 patients who underwent unilateral frontalis sling ptosis repair were retrospectively reviewed. An eyelid crease incision was used in all cases, with suturing of the sling material directly to tarsus. RESULTS: Preoperative diagnosis for all patients was either unilateral poor-function blepharoptosis or ptosis associated with levator synkinesis. Underlying causes included 75 congenital, 13 posttraumatic, 11 congenital "jaw-winking," 10 cranial nerve III palsies, 9 myasthenia gravis, 5 chronic progressive external ophthalmoplegia, and 4 congenital "double-elevator" palsies. There was a mean follow-up of 11.6 months. Twenty-eight eyelids required reoperation: 11 for undercorrection, 6 for overcorrection with keratopathy, 2 for upper eyelid crease revision, 7 for correction of poor contour, 1 for a broken sling, and 1 for removal of an infected exposed polytetraflouroethylene sling. Lagophthalmos of greater than 2 mm was noted in 18 patients, 5 of whom had persistent keratopathy requiring reoperation. No other complications were reported, except for 1 suture granuloma. Good to excellent final postoperative eyelid height was achieved in 121 patients (95%) after all surgeries and with conscious recruitment of the frontalis muscle. A large majority of patients and/or parents expressed satisfaction with the final cosmetic result and were not bothered by any asymmetric lagophthalmos in downgaze or lack of a synchronous blink. However, 19 of 25 amblyopic patients were less satisfied with passive eyelid height as they failed to recruit the ipsilateral frontalis muscle to activate the sling during binocular viewing. In 17 of these 19 patients, good to excellent eyelid height could be achieved with conscious active brow elevation. CONCLUSIONS: Unilateral sling provides good to excellent functional and cosmetic results in unilateral poor-function ptosis. However, patients with amblyopia usually require conscious effort to activate the frontalis muscle to achieve satisfactory eyelid height.

Adolescent↗
PubMed2005

A key to canthopexy: the tarsal strap. A fresh cadaveric study.

BACKGROUND: This article describes a poorly understood yet clinically significant eyelid structure the authors have labeled the tarsal strap. The tarsal strap anchors the tarsus to the periosteum of the inferolateral orbit. Releasing this tethering band is the cornerstone of achieving lasting, superior surgical results during lateral canthopexy and periorbital restoration in aesthetic and reconstructive surgery. METHODS: An 87-year-old, male, fresh cadaveric head of Caucasian origin was studied. The dissection was repeated on 15 cadaver heads, including both male and female cadavers, from various ethnic backgrounds, to confirm the anatomy of the tarsal strap described in this article. RESULTS: The tarsal strap was identified in all 16 cadaver dissections and appeared in a consistently similar location. CONCLUSIONS: Until now, the tarsal strap has been a poorly understood entity, despite being an anatomically and clinically significant eyelid structure. Knowledge of its significance is essential to restoring the lateral canthus and returning periorbital structures to their youthful state. It should be routinely sought out and properly released.

Aged, 80 and over↗
PubMed2006

Revisiting upper eyelid anatomy: introduction of the septal extension.

BACKGROUND: The current trend in plastic surgery of the eyelid has taken on increased dependence on anatomical considerations in the marriage of aesthetic and functional ideals. Often, the plastic surgeon performs ptosis and/or septal surgery in conjunction with blepharoplasty. The relationship between eyelid adnexal structures and upper eyelid function is a delicate but critical one. Current anatomical description states that the septum does not reach the superior tarsal border and inserts at a variable level on the levator aponeurosis. Conflicting observations in clinical practice stimulated this study to delineate the septal relationship to surrounding structures. In addition, this study may help to explain the increased rate of recurrence in ptosis repairs that incorporate plication techniques. METHODS: Dissection of four fresh cadaveric upper lid specimens in situ along with hematoxylin and eosin and trichrome stains of harvested eyelid tissue were used to redefine septal anatomy. Clinical case correlations are made to illustrate the significance of the histologic findings. RESULTS: A distinct septal extension was demonstrated arising from the orbital septum and covering preaponeurotic fat and tarsus completely. Histology of the anterior lamellae confirmed the presence of this thin fibrous sheet. In vivo assessment of this structure verifies its dynamic role in upper lid function. The clinical ramifications of this anatomical nuance are realized. CONCLUSIONS: A septal extension to the ciliary margin of the upper eyelid is established. Suture plication of the septal extension can induce lid elevation, with potential postoperative lid retraction. Intraoperative failure to recognize and distinguish this extension from the aponeurosis proper may lead to the high reported rates of unsuccessful ptosis correction. This refinement of septal anatomy should increase precision and help surgeons avoid complications in advanced blepharoplasty and ptosis surgery.

Blepharoplasty↗
PubMed2006

Thickness of Korean upper eyelid skin at different levels.

This study aims at elucidating the thickness of the Korean upper eyelid at different levels. Left eyelids of 10 (9 males and 1 female) fresh Korean cadavers were dissected. Full thickness upper eyelids were cut and trichrome stained. The thickness was measured under a microscope.The thickness of upper eyelid skin varied at different levels. The thickest part of the upper eyelid is just below the eyebrow (D) (1.127 +/- 238 microm), and the thinnest skin is near the ciliary margin (A) (320 +/- 49 microm). The upper tarsal area (C) and mid tarsal area (B) are 832 +/- 213 and 703 +/- 103 microm, respectively. "A" area was significantly thinner than mid tarsal "B" area (P = 0.000). The skin above the tarsus was thicker than the "B" area, but there was no significant difference (P = 0.081). The skin just below the eyebrow, "D," was thicker than the upper tarsal border, "C" area (P = 0.011). The epidermis accounted for 11.2% of the entire skin near the ciliary margin. However, epidermis presented less (4.2-5.5%) of the whole skin at other levels (P = 0.000). The distance between ciliary margin and the point where the skin turns suddenly thicker was 1.89 +/- 0.23 mm. The size of the tarsal plate was 8.88 +/- 0.81 mm. These data of upper eyelid skin thickness may apply to Asian double fold surgery and also to full thickness skin donation for grafting.

Adult↗
PubMed1999

Confirmation of arterial deficiencies in a limb with necrosis following clubfoot surgery.

This study describes postoperative necrosis of the hallux and first ray in a child with clubfoot. Arteriography performed on this child's lower limbs demonstrated, in the operated leg, hypoplasia of both the anterior and posterior tibial arteries and failure of the dorsalis pedis artery to traverse the tarsus and complete the deep plantar arch. Previously, congenital vascular deficiency was suggested to predispose such operated limbs to necrosis. These findings confirm the association between vascular deficiency and necrosis. In this present study, the metabolic demands of wound healing were sufficient in a limb with vascular deficiency to cause localized distal hypoperfusion leading to cyanosis and necrosis of the hallux and medial foot.

Abnormalities, Multiple↗
PubMed2004

A strong association between immune responsiveness and natal dispersal in a songbird.

Because parasite faunas typically show considerable spatio-temporal variation, and because parasites can have important fitness consequences, host defence mechanisms, including the immune system, can be expected to coevolve with natal dispersal, i.e. the movement of a newborn individual from its site of birth to its first site of reproduction. We demonstrate that immigrant individuals show a significantly higher humoral immune response towards a novel antigen than do local recruits in two independent populations of the great tit (Parus major). There was no effect of age, sex, tarsus length or body mass on immune responsiveness. Our results are consistent with the idea that phenotype-dependent dispersal and/or dispersal-by-phenotype-dependent selection establish a relation between immune responsiveness and natal dispersal.

Age Factors↗
PubMed2002

Brighter yellow blue tits make better parents.

Whether or not bird ornaments are a signal for direct (e.g. good parents) or indirect (e.g. good genes) benefits to prospective partners in sexual selection is controversial. Carotene coloration in Parus species is directly related to the ingestion of caterpillars, so that a brightly carotene-coloured tit may be signalling its ability to find caterpillars, a main high-quality food source for good fledgling development, and hence its parental abilities. If carotene-based plumage coloration is related to the good-parent hypothesis, we predict that yellow plumage brightness of tit fathers should be positively correlated to their investment in offspring provisioning. Here, we use cross-fostering experiments in blue tits (Parus caeruleus) to show that chick development (as measured by tarsus length) is related to yellowness of the foster father, but not to that of the genetic parents. Using these data, we were able to measure, for the first time to our knowledge, the separate contribution of genetic and environmental factors (i.e. parental plumage coloration) to chick development, and hence parental investment. Our data, which relate carotenoid coloration to models of good parents, and data from other authors, which relate ultraviolet coloration to good-genes models, stress that different kinds of coloration within an individual may provide different units of information to prospective females.

Animals↗
PubMed2002

The manipulation of food resources reveals sex-specific trade-offs between parental self-feeding and offspring care.

Parent Palestine sunbirds (Nectarinia osea) feed on flower nectar that is not fed to their nestlings. This phenomenon provided a unique opportunity to manipulate self-feeding rates of parent birds independently of the rate at which they feed arthropod prey to their offspring. Based on provisioning models, we predicted that parents would invest more in their young as the energy content of their own food increased. From our earlier work, we also predicted that the levels of sex-specific activities of males and females would differ as the energy content of their food increased. Sunbird pairs with two or three nestlings were provided with feeders containing a low-, medium- or high-concentration sucrose solution. As the sugar concentration increased, the females delivered arthropods at a greater rate to their nestlings, removed proportionally more faecal sacs and spent longer at the nest, while the males increased their mobbing effort. Nestling food intake and body mass, but not tarsus length or bill size, were larger in small broods than in large broods, and increased with increasing feeder sugar concentration. These results imply that increasing the energy content of food consumed by parent sunbirds allows them to increase the rate at which other foods are delivered to their young and to increase other parental care activities as well. The results also add credence to the idea that behavioural decisions reflect life-history trade-offs between parental self-feeding and investment in current young.

Animals↗
PubMed2003

Experimental manipulation of egg carotenoids affects immunity of barn swallow nestlings.

The yolk of bird eggs contains maternal carotenoids that may act as antioxidants thus influencing offspring performance and survival. However, to our knowledge, this hypothesis has not been subjected to experimental tests and the function of transmission of carotenoids to the egg is largely unknown. We directly manipulated the concentration of the main carotenoid (lutein) in the eggs of barn swallows (Hirundo rustica) and analysed the effect of experimental manipulation on growth of nestlings and two fundamental components of their acquired immunity. Nestlings hatched from lutein-inoculated eggs had larger T-cell-mediated immune response compared with those of two control groups. T-cell-mediated immune response predicted nestling survival until fledging. However, lutein inoculation did not affect antibody response to an immunogen, body mass, tarsus length or plumage development. Nestling body mass and plumage development declined with egg laying order, but the effects of lutein inoculation were independent of egg laying order for all traits. Our results show that maternal yolk carotenoids can have a major effect in promoting a fundamental component of immunity that predicts offspring survival and suggests that adaptive early maternal effects can be mediated by transmission of antioxidants to eggs.

Animals↗
PubMed2005

First identifiable Mesozoic harvestman (Opiliones: Dyspnoi) from Cretaceous Burmese amber.

Two inclusions in a piece of Upper Cretaceous (Albian) Burmese amber from Myanmar are described as a harvestman (Arachnida: Opiliones), Halitherses grimaldii new genus and species. The first Mesozoic harvestman to be named can be referred to the suborder Dyspnoi for the following reasons: prosoma divided into two regions, the posterior formed by the fusion of the meso- and metapeltidium; palp lacking a terminal claw, with clavate setae, and tarsus considerably shorter than the tibia. The bilobed, anteriorly projecting ocular tubercle is reminiscent of that of ortholasmatine nemastomatids. The status of other Mesozoic fossils referred to Opiliones is briefly reviewed.

Amber↗
PubMed1999

Role of the Bicoid-related homeodomain factor Pitx1 in specifying hindlimb morphogenesis and pituitary development.

Pitx1 is a Bicoid-related homeodomain factor that exhibits preferential expression in the hindlimb, as well as expression in the developing anterior pituitary gland and first branchial arch. Here, we report that Pitx1 gene-deleted mice exhibit striking abnormalities in morphogenesis and growth of the hindlimb, resulting in a limb that exhibits structural changes in tibia and fibula as well as patterning alterations in patella and proximal tarsus, to more closely resemble the corresponding forelimb structures. Deletion of the Pitx1 locus results in decreased distal expression of the hindlimb-specific marker, the T-box factor, Tbx4. On the basis of similar expression patterns in chick, targeted misexpression of chick Pitx1 in the developing wing bud causes the resulting limb to assume altered digit number and morphogenesis, with Tbx4 induction. We hypothesize that Pitx1 serves to critically modulate morphogenesis, growth, and potential patterning of a specific hindlimb region, serving as a component of the morphological and growth distinctions in forelimb and hindlimb identity. Pitx1 gene-deleted mice also exhibit reciprocal abnormalities of two ventral and one dorsal anterior pituitary cell types, presumably on the basis of its synergistic functions with other transcription factors, and defects in the derivatives of the first branchial arch, including cleft palate, suggesting a proliferative defect in these organs analogous to that observed in the hindlimb.

Animals↗
PubMed2000

Theory of arachnid prey localization.

Sand scorpions and many other arachnids locate their prey through highly sensitive slit sensilla at the tips (tarsi) of their eight legs. This sensor array responds to vibrations with stimulus-locked action potentials encoding the target direction. We present a neuronal model to account for stimulus angle determination using a population of second-order neurons, each receiving excitatory input from one tarsus and inhibition from a triad opposite to it. The input opens a time window whose width determines a neuron's firing probability. Stochastic optimization is realized through tuning the balance between excitation and inhibition. The agreement with experiments on the sand scorpion is excellent.

Action Potentials↗
PubMed2001

The evolution of sexual size dimorphism in the house finch. III. Developmental basis.

Sexual size dimorphism of adults proximately results from a combination of sexually dimorphic growth patterns and selection on growing individuals. Yet, most studies of the evolution of dimorphism have focused on correlates of only adult morphologies. Here we examined the ontogeny of sexual size dimorphism in an isolated population of the house finch (Carpodacus mexicanus). Sexes differed in growth rates and growth duration; in most traits, females grew faster than males, but males grew for a longer period. Sexual dimorphism in bill traits (bill length, width, depth) and in body traits (wing, tarsus, and tail length; mass) developed during different periods of ontogeny. Growth of bill traits was most different between sexes during the juvenile period (after leaving the nest), whereas growth of body traits was most sexually dimorphic during the first few days after hatching. Postgrowth selection on juveniles strongly influenced sexual dimorphism in all traits; in some traits, this selection canceled or reversed dimorphism patterns produced by growth differences between sexes. The net result was that adult sexual dimorphism, to a large degree, was an outcome of selection for survival during juvenile stages. We suggest that previously documented fast and extensive divergence of house finch populations in sexual size dimorphism may be partially produced by distinct environmental conditions during growth in these populations.

Animals↗
PubMed2004

Terminal investment induced by immune challenge and fitness traits associated with major histocompatibility complex in the house sparrow.

The terminal investment hypothesis predicts that individuals should invest more in their present reproduction if they are less likely to survive to future reproductive events. Infections, which reduce viability, may be used by individuals as a cue of a diminishing residual reproductive value and could therefore theoretically trigger an intensification of breeding effort. We tested this hypothesis in a natural population of house sparrows (Passer domesticus). We manipulated the immune system of breeding females by injecting them with a vaccine against the Paramyxo virus, the agent of Newcastle disease. Females were captured and treated immediately after completion of their first clutch either with the vaccine (NDV) or with phosphate buffered saline (PBS). The entire clutch was subsequently removed. We also screened Mhc class I genes of females to assess possible genotype-by-immune treatment interactions on reproductive investment. Our results indicate that vaccinated females were more likely to lay replacement clutches and that the difference in number of eggs between first and replacement clutches was greater for NDV females than for controls. In addition, chick size, both in terms of tarsus length and body mass, was affected by immune activation but in interaction with nestling age and female body mass, respectively. Mhc genotype-by-immune treatment interactions were never significant; however, allelic diversity was positively correlated with nestling survival. These results show that immune system activation is potentially used as a cue of reduced survival prospect and appears to induce a costly terminal investment behavior, and Mhc diversity might be under selection in a natural population of house sparrows.

Animals↗
PubMed2005

An immunohistochemical study of the extracellular matrix of the tarsal plate in the upper eyelid in human beings.

The superior tarsus is a plate of tissue that stiffens the upper eyelid, gives it support and determines its form. The purpose of the present study was to relate the composition of its extracellular matrix to its function and to report regional differences that may influence the activity of its Meibomian glands. Fourteen methanol-fixed specimens were cryosectioned for immunohistochemistry and labelled with a panel of monoclonal antibodies against a wide range of collagens, glycosaminoglycans and proteoglycans. Labelling was detected with avidin-biotin-peroxidase. A further six specimens were formalin-fixed for routine histology. The tarsal plate immunolabelled strongly for types I, III and VI collagen and for aggrecan, versican, tenascin, cartilage oligomeric matrix protein (COMP) together with a variety of glycosaminoglycans (notably chondroitin 6 sulphate). A region of strong labelling for aggrecan, dermatan sulphate and chondroitin 6 sulphate immediately surrounded the Meibomian glands. The site of labelling corresponded to a layer of acellular and amorphous matrix seen histologically that we have termed the 'territorial matrix'. The results suggested that the tarsal plate is a specialized connective tissue that is neither purely fibrous nor cartilaginous, yet has an aggrecan content that probably contributes to its stiffness. Its unique character highlights the challenge in choosing an ideal mechanical substitute. As patients with rheumatoid arthritis often have problems relating to tear film deficiency, the ability of aggrecan or COMP to act as autoantigens may be significant. An immune reaction directed against these molecules could alter tarsal gland function by interfering with the interaction between the glands and their territorial matrix.

Adult↗
PubMed2007

Sex and testosterone effects on growth, immunity and melanin coloration of nestling Eurasian kestrels.

1. Sex differences in testosterone levels and sex-biased sensitivity to testosterone are the basis of some ideas postulated to account for sex-linked environmental vulnerability during early life. However, sex variation in circulating testosterone levels has been scarcely explored and never manipulated at post-natal stages of birds in the wild. 2. We measured and experimentally increased circulating testosterone levels in nestling Eurasian kestrels Falco tinnunculus. We investigated, possible sexual differences in testosterone levels and the effect of this hormone on growth (body mass and tarsus length) and cell-mediated immunity in males and females. We also explored testosterone effects on rump coloration, a highly variable melanin-based trait in male nestlings. We analysed data on circulating testosterone levels of nestlings in 15 additional bird species. 3. Increased levels of testosterone tended to negatively affect body condition, reduced cell-mediated immune responses in male and female nestlings and also diminished the expression of grey rump coloration in male nestlings. No sex differences were observed in testosterone levels in either control or increased testosterone group nestlings, and no interactions were found between sex and treatment. However, male nestlings showed a lower cell-mediated immune response than females in both groups. 4. Our results indicate first, that a high level of testosterone in all nestlings in a brood entails costs, at least in terms of immunity, coloration and probably growth. Secondly, sex differences in post-natal cell-mediated immunity, and consequently in the capacity to prevent diseases, cannot be explained by sex differences in circulating testosterone levels. Finally, by comparing published data at an interspecific level, contradictory sex patterns in circulating testosterone levels have been found, supporting the idea that circulating testosterone might not be a proximate factor causing sex-dependent vulnerability in bird species.

Aging↗
PubMed2005

How do misassigned paternities affect the estimation of heritability in the wild?

Studies of birds have recently played an important role in the increasing success of quantitative genetics applied to natural populations. However, these studies mostly base their pedigree relationships on social information, despite the known widespread genetic polygamy in avian species. Here, we study the influence of misassigned paternities, combined with the effect of pedigree size and depth, on the estimation of heritability. First, we compute simulations of a polygenic trait for two levels of heritability (0.1 and 0.4), several extra-pair paternity rates (ranging from 5% to 40%), and varying sample sizes (20, 50 and 100 broods) or pedigree depth (2 or 4 generations). We compare heritability estimates from the social and the genetic pedigree, running a restricted maximum-likelihood 'animal model'. Social pedigree underestimates heritability by an average of 0-17% for 5-20% extra-pair paternities and by up to 18% for 40% extra-pair paternities and a heritability of 0.4. Second, we identifyied extra-pair offspring using microsatellite loci in two populations of blue tits (Parus caeruleus) showing high levels of extra-pair paternities (15% and 25% of extra-pair offspring). We compare heritabilities of tarsus length and body mass estimated with pedigrees of increasing accuracy. These analyses suggest that the bias induced by misassigned paternities on heritability estimation depends on the level of heritability and the rate of paternity error. Typical rates of extra-pair paternities in birds (around 20% of offspring) should result in an underestimation of heritability of less than 15% when estimated over a minimum of 100 broods.

Animals↗
PubMed1993

Histology and histomorphometry of the tibial diaphyseal growth in two turkey strains during the first six weeks after hatching.

The comparative cortical growth of the tibio-tarsus was studied during the first six weeks after hatching in two turkey strains, a light and a heavy one. At one day post-hatching the cortical appeared to be constituted in both strains of an embryonic non-active fibrous bone tissue which had completely disappeared at one week. On and after one week the cortex was constituted of a fibrolamellar adult bone tissue elaborated on the periosteal part of the cortex. Its vascular pattern depended on the strain and on the thickness of the cortical faces. The histomorphometric studies showed that the growth in thickness was earlier and faster in the heavy strain with a Total Diaphyseal Surface twice larger at 6 weeks but a Diaphyseal Cortical Ratio not significantly different since 3 weeks of age.

Animals↗