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Clinical study of single-suture inferior retractor repair for involutional entropion.

PURPOSE: To evaluate the clinical efficacy of a simplified single-suture inferior retractor repair technique for involutional entropion. METHODS: A retrospective study of 20 patients (26 eyelids), followed for 6 months at our hospital, who showed no severe horizontal lid laxity were operated on for involutional entropion. After subciliary incision, the inferior retractor was identified and repaired by reattaching the superior edge of the inferior retractor to the inferior edge of the lower tarsus by a single suture using 5-0 prolene. RESULTS: 26 eyelids of 20 patients (80.8%) were treated successfully without recurrence. Complications were seen in 5 eyelids, 2 were overcorrections and 3 were recurrences of entropion. Recurred cases were reoperated on and showed good postoperative results after the second surgery. CONCLUSIONS: The simplified single-suture inferior retractor repair had good results in patients with involutional entropion without severe horizontal lid laxity. Moreover, this procedure had a short operation and recovery time. In unilateral cases, we could achieve more symmetric appearance when compared with bilateral surgeries.

Aged↗

The predatory strike of free ranging praying mantises, Sphodromantis lineola (Burmeister). I: Strikes in the mid-sagittal plane.

The predatory behavior of free ranging praying mantises, Sphodromantis lineola (Burmeister), in response to prey at various positions in the midsagittal plane, was examined using high speed (200 frames per second) videography. Predatory strikes fell neatly into two categories based on the elevation of the prey from the surface on which the mantises stood: high strikes and low strikes. When the prey was 35 degrees or more above the surface (measured from the mesothoracic tarsus), mantises assumed a posture that elevated and pointed the body upwards (high strikes). When prey was near or below the surface on which the mantises stood, they assumed a posture that lowered the body and shifted its center of gravity forward (low strikes). Each of these two initial postures was followed by distinctly different constellations of movements, which included a rapid grasping movement of the raptorial forelegs and, if the prey was sufficiently distant, a displacement of the body upwards (high strikes) or forwards (low strikes). Our analyses suggest that prothoracic angle and, to a lesser degree, head angle and the degree to which the mesothoracic legs are extended provide the critical proprioceptive cues used in programming the appropriate attach sequence. Based on our results, we hypothesize that mantises process visual and proprioceptive information indicating prey location in 'pterothorax-centered space'.

Animals↗

Arboreality and bipedality in the Hadar hominids.

Numerous studies of the locomotor skeleton of the Hadar hominids have revealed traits indicative of both arboreal climbing/suspension and terrestrial bipedalism. These earliest known hominids must have devoted part of their activities to feeding, sleeping and/or predator avoidance in trees, while also spending time on the ground where they moved bipedally. In this paper we offer new data on phalangeal length and curvature, morphology of the tarsus and metatarsophalangeal joints, and body proportions that further strengthen the argument for arboreality in the Hadar hominids. We also provide additional evidence on limb and pedal proportions and on the functional anatomy of the hip, knee and foot, indicating that the bipedality practiced at Hadar differed from that of modern humans. Consideration of the ecology at Hadar, in conjunction with modern primate models, supports the notion of arboredality in these earliest australopithecines. We speculate that selection for terrestrial bipedality may have intensified through the Plio-Pleistocene as forests and woodland patches shrunk and the need arose to move increasingly longer distances on the ground. Only with Homo erectus might body size, culture and other factors have combined to 'release' hominids from their dependence on trees.

Adaptation, Biological↗

Down-regulation of murine collagen-induced arthritis by a T cell hybridoma.

T cell hybridoma cell lines were generated by somatic cell fusion of BW 5147 myeloma cells and splenic cells from mice suppressed for collagen-induced arthritis (CIA). Two cell lines were characterized for their cell surface phenotype, antigen recognition and capacity to down-regulate the erythema and edema associated with CIA. Cell line T101N was determined to portray the cell surface phenotype Ly1+2- L3T4- Thy1+ by a direct binding assay. Cell line T104B1 was determined to express only the Thy1+ alloantigen. Panning studies, measurement of IL-2 production in vitro and the suppression of antibodies to type I and type II collagen in vivo indicate that the hybridoma cells are not isotype specific in their recognition of the polymorphic interstitial collagens. Down-regulation of the erythema and edema of CIA occurred on injection of 1 X 10(5) T101N cells but not T104B1 cells. Histology of the tarsus region of the hind paw of CIA mice 33 days after the administration of T101N cells showed contrasting histopathology compared to that of CIA mice. The joints of CIA mice given T101N cells showed aligned articular surfaces resembling normal joint structure and only residual pannus. The data indicate that collagen-specific cloned T cell lines can modulate the gross pathology and joint architecture of joints exhibiting CIA.

Animals↗

[Ptosis surgery: anterior approach for levator aponeurosis shortening (author's transl)].

A simplified method for ptosis surgery has been used in 33 patients. The levator aponeurosis is exposed by the anterior approach. It is folded or excised and reattached to the anterior surface of the tarsus, matching the level and the contour of the two upper lids. The cosmetic appearance of the lid is improved by the skin closure technique. This method for ptosis surgery meets the anatomical and physiological needs best. It has given very satisfactory functional and cosmetic results.

Adolescent↗

Evolution of the human foot: evidence from Plio-Pleistocene hominids.

The human foot serves a dual role during locomotion. It functions at times as a mobile structure and at times as a rigid lever. The human foot shows the hallmarks of an arboreal heritage wherein the foot was primarily a grasping organ. Over the course of the human career the human foot has evolved an elaborate plantar aponeurosis, strong plantar ligaments, longitudinal arches, an enlarged musculus flexor accessorius, an adducted (non-opposable) hallux, a remodeled calcaneocuboid joint, a long tarsus, and shortened toes (II to V). Comparisons of the chimpanzee and human foot allow us to reconstruct the pathway of foot evolution. Fossil foot bones of Homo habilis, dated at 1.76 million years, are remarkably like those of modern humans. Foot bones from Hadar, dated at around 3.5 million years, are remarkably chimpanzee-like, with only incipient human traits. The surprising chimpanzee-like qualities of the Hadar fossils strongly support the use of living apes as models of ancestral pongidhominid morphotypes.

Adaptation, Biological↗

Culling rate of Icelandic horses due to bone spavin.

A survival analysis was used to compare the culling rate of Icelandic horses due to the presence of radiographic and clinical signs of bone spavin. A follow-up study of 508 horses from a survey five years earlier was performed. In the original survey 46% of the horses had radiographic signs of bone spavin (RS) and/or lameness after flexion test of the tarsus. The horse owners were interviewed by telephone. The owners were asked if the horses were still used for riding and if not, they were regarded as culled. The owners were then asked when and why the horses were culled. During the 5 years, 98 horses had been culled, 151 had been withdrawn (sold or selected for breeding) and 259 were still used for riding. Hind limb lameness (HLL) was the most common reason for culling (n = 42). The rate of culling was low up to the age of II years, when it rose to 0.05 for horses with RS. The risk ratio for culling was twice as high for horses with RS compared with horses without RS and 5.5 times higher for culling because of HLL. The risk of culling (prognostic value) was highest for the combination of RS with lameness after flexion test, next highest for RS and lowest for lameness after flexion test as the only finding. It was concluded that bone spavin affects the duration of use of Icelandic horses and is the most common cause of culling due to disease of riding horses in the age range of 7-17 years.

Animals↗

Chip-mediated partnerships of the homeodomain proteins Bar and Aristaless with the LIM-HOM proteins Apterous and Lim1 regulate distal leg development.

Proximodistal patterning in Drosophila requires division of the developing leg into increasingly smaller, discrete domains of gene function. The LIM-HOM transcription factors apterous (ap) and Lim1 (also known as dlim1), and the homeobox genes Bar and aristaless (al) are part of the gene battery required for the development of specific leg segments. Our genetic results show that there are posttranslational interactions between Ap, Bar and the LIM-domain binding protein Chip in tarsus four, and between Al, Lim1 and Chip in the pretarsus, and that these interactions depend on the presence of balanced amounts of such proteins. We also observe in vitro protein binding between Bar and Chip, Bar and Ap, Lim1 and Chip, and Al and Chip. Together with the previous evidence for interactions between Ap and Chip, these results suggest that these transcription factors form protein complexes during leg development. We propose that the different developmental outcomes of LIM-HOM function are due to the precise identity and dosage of the interacting partners present in a given cell.

Animals↗

Expression of epithelial alkaline phosphatase in segmentally iterated bands during grasshopper limb morphogenesis.

Although the study of rostral-caudal segmentation of the insect body has been a rich source of information about embryonic pattern formation, relatively little is known of the process of proximal-distal segmentation of insect appendages. Here we demonstrate that during the period of limb segmentation, five segmentally iterated, sharply demarcated bands of cell surface alkaline phosphatase activity are expressed in embryonic grasshopper limbs. These bands span each intersegmental boundary in the limb as well as one boundary within the tarsus. Within appendages, expression is restricted to epithelial cells, where activity is present on both apical and basolateral surfaces. This epithelial alkaline phosphatase remains active at neutral pH, is insensitive to levamisole inhibition, and is strongly inhibited by nucleoside monophosphates. Treatment of embryos with phosphatidylinositol-specific phospholipase C releases almost all visible chromogenic activity, indicating that the epithelial alkaline phosphatase is anchored to the plasma membrane by glycosyl-phosphatidylinositol. When material released by phosphatidylinositol-specific phospholipase C is separated on native polyacrylamide gels, a single broad band of enzymatic activity is detected following incubation with substrate. A polyclonal antiserum raised against a 55 x 10(3) M(r) alkaline phosphatase from shrimp recognizes a single band of 56 x 10(3) M(r) on immunoblots of grasshopper membrane proteins. The spatially restricted expression of epithelial alkaline phosphatase suggests that it may be involved in epithelial cell rearrangements or shape changes associated with limb segmentation and morphogenesis. It also may contribute to definition of axon routes in the limb, since pioneer afferent growth cones turn at, and migrate along, the edge of one alkaline phosphatase-expressing epithelial domain.

Alkaline Phosphatase↗

The roles of the homeobox genes aristaless and Distal-less in patterning the legs and wings of Drosophila.

In the leg and wing imaginal discs of Drosophila, the expression domains of the homeobox genes aristaless (al) and Distal-less (Dll) are defined by the secreted signaling molecules Wingless (Wg) and Decapentaplegic (Dpp). Here, the roles played by al and Dll in patterning the legs and wings have been investigated through loss of function studies. In the developing leg, al is expressed at the presumptive tip and a molecularly defined null allele of al reveals that its only function in patterning the leg appears to be to direct the growth and differentiation of the structures at the tip. In contrast, Dll has previously been shown to be required for the development of all of the leg more distal than the coxa. Dll protein can be detected in a central domain in leg discs throughout most of larval development, and in mature discs this domain corresponds to the distal-most region of the leg, the tarsus and the distal tibia. Clonal analysis reveals that late in development these are the only regions in which Dll function is required. However, earlier in development Dll is required in more proximal regions of the leg suggesting it is expressed at high levels in these cells early in development but not later. This reveals a correlation between a temporal requirement for Dll and position along the proximodistal axis; how this may relate to the generation of the P/D axis is discussed. Dll is required in the distal regions of the leg for the expression of tarsal-specific genes including al and bric-a-brac. Dll mutant cells in the leg sort out from wild-type cells suggesting one function of Dll here is to control adhesive properties of cells. Dll is also required for the normal development of the wing, primarily for the differentiation of the wing margin.

Alleles↗

Ontogenesis of the attachment ability in the bug Coreus marginatus (Heteroptera, Insecta).

Each tarsus of Coreus marginatus L. (Coreidae) bears a pair of smooth flexible pulvilli adapted for attachment to relatively smooth surfaces, such as their host plant Rumex crispus L. (Polygonaceae). This account quantifies insect attachment abilities on smooth surfaces at various stages of ontogenesis. Friction (shear) force (FF) of adults and juvenile insects was measured by the use of a computer controlled centrifugal force tester equipped with a fibre optical sensor. Pad area, body size and body mass were determined individually for each experimental insect. Light microscopy revealed no difference in pulvilli area between different leg pairs. Pulvilli area demonstrated a stronger increase with increasing linear dimensions, as predicted by scaling laws. Since friction coefficient (relationship between FF and body weight) (FC) was always higher than 1, it was concluded that adhesion has strongly contributed to the measured friction. The frictional properties of pulvilli do not change during ontogenesis. Thus, only the growth of pulvilli and, therefore, the increased contact area, contribute to the increasing attachment ability in insects at later larval stages. Due to different scaling of the body mass and area of attachment organs, smaller insects attach relatively more strongly. Both FF and FC were higher in experiments in which higher angular acceleration (AC) was applied. Lateral tenacity determined individually for experimental insects and pooled for all animals and accelerations is 0.097 N m(-2). These data led us to suggest that viscosity of the pad secretion and/or visco-elastic properties of the foam-like material of pulvilli play an important role in the attachment ability of insects.

Animals↗

The effects of behaviourally relevant temperatures on mechanosensory neurones of the grasshopper, Schistocerca americana.

Grasshopper mechanosensory hair neurones respond to displacement of their associated hairs in a temperature sensitive manner: comparable increases in the number of spikes per stimulus result from increases in temperature with constant stimulus strengths and from increasing stimulus strengths at constant temperature. It is therefore not obvious that neurones in the CNS which receive inputs from mechanosensory hairs would be able to distinguish between these two parameters. The temperatures which populations of mechanosensory hairs on the thorax, head and tarsus experienced were measured in freely moving animals. Animals in thermally heterogeneous environments spent 90% of the accounted time in locations where thoracic temperatures of 32-44 degrees C were maintained (the behaviourally 'preferred' range). Head temperatures covered a wider range, and tarsal temperatures the widest. Different populations of mechanosensory hair neurones exhibited different sensitivities to temperature. Thoracic hair neurones were significantly more temperature sensitive than one of the two populations of head hairs studied, and tarsal hairs exhibited a pronounced temperature compensation in the behaviourally 'preferred' range. Wind sensitive head hairs, however, showed exceptionally high temperature sensitivities. There is a negative correlation between the temperature sensitivity of a population of mechanosensory hair neurones and the temperature variability to which those neurones are normally exposed. Implications of this correlation for the central interpretation of mechanosensory input are considered.

Animals↗

Innervation patterns of inhibitory motor neurones in the thorax of the locust.

The innervation pattern of inhibitory motor neurones of the locust has been revealed by intracellular recording from their cell bodies in the meso- and metathoracic ganglion and simultaneous recording from muscle fibres in a middle, or in a hind leg. Three neurones in each ganglion, the common inhibitor (CI = CI1), the anterior inhibitor (AI = CI2), and the posterior inhibitor (PI = CI3) innervate several muscles in one leg and are thus common inhibitory neurones. Metathoracic CI innervates 13 muscles in one hind leg and mesothoracic CI innervates 12 muscles in one middle leg. The muscles are all in the proximal parts of the legs and move the coxa, the trochanter and the tibia. Metathoracic AI and PI innervate four muscles in the more distal parts of one hind leg that move the tibia, the tarsus and the unguis. None of these muscles is innervated by CI. Each inhibitor innervates muscles that have different and often antagonistic actions during movements of a leg. AI and PI receive many synaptic inputs in common and show similar patterns of spikes during imposed movements of a tibia. Tests fail, however, to reveal evidence for any electrical or synaptic coupling between them. A revised scheme of nomenclature for these inhibitory neurones is proposed.

Animals↗

Local movements evoked by chemical stimulation of the hind leg in the locust Schistocerca gregaria.

The behavioural responses of desert locusts, Schistocerca gregaria, to solutions of four behaviourally relevant chemicals (sodium chloride, sucrose, nicotine hydrogen tartrate and lysine glutamate) applied as droplets to the hind tarsus were analysed. All responses following within 1 s of chemical stimulation were local leg avoidance reflexes, and the probability of eliciting such a response increased in a dose-dependent manner with increasing concentration for all the chemicals tested. Chemical identity, however, critically determined the concentration threshold at which the different chemicals became an effective stimulus. For example, a 2.5 mmol l(-)(1) concentration of the secondary plant metabolite nicotine hydrogen tartrate (NHT), a potent feeding deterrent to locusts, was sufficient to evoke avoidance responses in 50 % of cases, whilst for the nutrients, sucrose and lysine glutamate, 250-500 mmol l(-)(1) of the chemical was needed to induce avoidance behaviour in 50 % of the locusts. NaCl was of intermediate effectiveness, with a 50 % response rate occurring at a concentration of approximately 50 mmol l(-)(1). The latency to the start of the response following stimulation was negatively correlated with the concentration of NaCl, but for the other chemicals concentration had no effect on latency. The duration of the avoidance behaviour decreased with increasing concentration for NaCl and more weakly for NHT, but not for the other chemicals. Adding a subthreshold concentration of sucrose to 50 mmol l(-)(1) NaCl decreased the incidence of response compared with 50 mmol l(-)(1) NaCl on its own. Experiments with other mixtures combining NaCl, sucrose and NHT indicate that the frequency and dynamics of the responses to chemical mixtures cannot be simply predicted from the responses to their individual constituents.

Animals↗

Performance and adaptive value of tarsal morphology in rove beetles of the genus Stenus (Coleoptera, Staphylinidae).

To evaluate the adaptive value of the widening of the bilobed tarsi that has paralleled the tremendous radiation of the staphylinid genus Stenus, the performance of slender versus wide tarsi has been evaluated in two different contexts: (i) locomotion on the surface of water, and (ii) climbing on vertical (plant) surfaces. Contact angle measurements at the underside of the tarsi have revealed that, irrespective of tarsus width, all the investigated species are well supported by the surface of water while walking on it. The main selective demands driving the widening of the tarsi in several lineages have instead come from their firm attachment to smooth plant surfaces. This is suggested by measurements of the maximum vertical pulling forces exerted by intact and manipulated individuals on various rough and smooth surfaces. Species with widened tarsi associated with considerably more tenet setae attain significantly higher pulling forces, particularly on smooth surfaces. The tarsal setae are of greater importance on smooth surfaces, but the claws seem to be more important on rough substrata. On substrata that combine the attributes of rough and smooth surfaces, both claws and tenent setae add significantly to the pulling forces exerted, suggesting a functional synergism. The contribution of the present study to our understanding of insect tarsal attachment to surfaces with a variety of textures is discussed.

Animals↗

Tarsal hypermobility after ankle fusion--fact or fiction?

Thirty-seven patients have been reviewed after arthrodesis of the ankle in order to determine the reduction of dorsiflexion and plantarflexion of the foot, the incidence of tarsal hypermobility and its relevance to the clinical results of this procedure. Radiological methods of measuring movements in the foot and tarsus are described and applied to patients who had a normal foot on the opposite side which could be used as a control. Our findings suggest that tarsal hypermobility is not as common as has hitherto been supposed and that a stiff foot with minor radiological degenerative changes in the tarsal joints is quite compatible with an excellent result.

Ankle Joint↗

Stress fractures in military recruits. A prospective study showing an unusually high incidence.

In a prospective study of 295 male Israeli military recruits a 31% incidence of stress fractures was found. Eighty per cent of the fractures were in the tibial or femoral shaft, while only 8% occurred in the tarsus and metatarsus. Sixty-nine per cent of the femoral stress fractures were asymptomatic, but only 8% of those in the tibia. Even asymptomatic stress fractures do, however, need to be treated. Possible explanations for the unusually high incidence of stress fractures in this study are discussed.

Adolescent↗

[Evaluation of the surgery results of Müller's muscle-conjunctival resection in the treatment of blepharoptosis].

OBJECTIVE: To evaluate the results of Müller's muscle-conjunctival resection for correction of blepharoptosis and to discuss the advantages of this procedure. METHODS: 38 patients (39 eyelids) were submitted to Müller's muscle-conjunctival resection. Blepharoptosis varied from 1.0 mm to 3.0 mm (mean: 2.0 mm). The amount of eyelid elevation produced by phenylephrine guided the amount of tissue to be resected. RESULT: 33 eyelids (85%) treated with this procedure were cosmetically acceptable. CONCLUSIONS: Müller's muscle-conjunctival resection procedure is a relatively simple technique for blepharoptosis, with good levator function and positive 10% phenylephrine test. The advantages are: preservation of tarsus and predictable results.

Adolescent↗