DERMATOLOGIC SURGERY, Issue 4 2005
Imre Bihari MD
Background. The accepted pathophysiology of telangiectasias is reflux from superficial or deep veins. There are physical signs and scientific findings that do not fit this theory but support the possibility of arteriovenous (AV) shunt origin. Objective. If there is a higher flow in spider veins than in the surrounding skin, it means that AV shunts participate in the circulation of the telangiectasia. On the other hand, slow flow indicates reflux as the etiologic factor. Method. Telangiectasias and the surrounding skin of 22 legs of 19 patients were examined with laser-Doppler equipment. Results. The probe over the spider vein found a higher flow value (average 28.2 perfusion units [PU]) than in the surrounding skin (15.6 PU) in 13 limbs, but it was significantly higher only in 5 cases. In 9 limbs, the flow was slower. Conclusion. We interpret the higher flow values as a consequence of open AV shunts. This means that AV shunt pathophysiology was present in some of our cases. IMRE BIHARI, MD, PHD, ANIKÓ MURÁNYI, MD, AND PéTER BIHARI, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. [source]

The mechanism of Drosophila leg development along the proximodistal axis

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2004
Tetsuya Kojima
During development of higher organisms, most patterning events occur in growing tissues. Thus, unraveling the mechanism of how growing tissues are patterned into final morphologies has been an essential subject of developmental biology. Limb or appendage development in both vertebrates and invertebrates has attracted great attention from many researchers for a long time, because they involve almost all developmental processes required for tissue patterning, such as generation of the positional information by morphogen, subdivision of the tissue into distinct parts according to the positional information, localized cell growth and proliferation, and control of adhesivity, movement and shape changes of cells. The Drosophila leg development is a good model system, upon which a substantial amount of knowledge has been accumulated. In this review, the current understanding of the mechanism of Drosophila leg development is described. [source]

Limb and tail lengths in relation to substrate usage in Tropidurus lizards

JOURNAL OF MORPHOLOGY, Issue 2 2001
Tiana Kohlsdorf
Abstract A close relationship between morphology and habitat is well documented for anoline lizards. To test the generality of this relationship in lizards, snout-vent, tail, and limb lengths of 18 species of Tropidurus (Tropiduridae) were measured and comparisons made between body proportions and substrate usage. Phylogenetic analysis of covariance by computer simulation suggests that the three species inhabiting sandy soils have relatively longer feet than do other species. Phylogenetic ANCOVA also demonstrates that the three species inhabiting tree canopies and locomoting on small branches have short tails and hind limbs. These three species constitute a single subclade within the overall Tropidurus phylogeny and analyses with independent contrasts indicate that divergence in relative tail and hind limb length has been rapid since they split from their sister clade. Being restricted to a single subclade, the difference in body proportions could logically be interpreted as either an adaptation to the clade's lifestyle or simply a nonadaptive synapomorphy for this lineage. Nevertheless, previous comparative studies of another clade of lizards (Anolis) as well as experimental studies of Sceloporus lizards sprinting on rods of different diameters support the adaptive interpretation. J. Morphol. 248:151,164, 2001. © 2001 Wiley-Liss, Inc. [source]

Comorbid conditions associated with Parkinson's disease: A population-based study

MOVEMENT DISORDERS, Issue 4 2006
Cynthia L. Leibson PhD
Abstract The burden of comorbidity in Parkinson's disease (PD) remains unclear. All Olmsted County, Minnesota, residents with incident PD in 1976,1995 (n = 197) plus one age- and sex-matched non-PD referent subject per case were followed for all clinical diagnoses from 5 years before through 15 years after index (i.e., year of PD onset for each case and same year for the referent subject). Both members of a case,referent pair were censored at death or emigration of either member to ensure equivalent follow-up. Cases and referent subjects were compared for summary comorbidity (Charlson index) and for the likelihood of having one or more diagnoses within each International Classification of Diseases chapter/subchapter. Before index, the groups were similar for all comparisons. After index, cases had a higher likelihood of diagnoses within the chapters "Mental Disorders" and "Diseases of the Genitourinary System," and within the subchapters "Organic Psychotic Conditions," "Other Psychoses," "Neurotic/Personality/Other Nonpsychotic Disorders," "Hereditary/Degenerative Diseases of Central Nervous System," "Symptoms," "Other Diseases of Digestive System," "Other Diseases of Urinary System," "Diseases of Veins/Lymphatics/Other Circulatory System Diseases," "Fractures of Lower Limb," "Other Diseases of Skin/Subcutaneous Tissue," "Osteopathies/Chrondropathies/Acquired Musculoskeletal Deformities," and "Pneumonia and Influenza." The excess morbidity and mortality observed for persons with PD are consistent with recognized PD sequelae. © 2005 Movement Disorder Society [source]

Innervation of the Pelvic Limb of the Adult Ostrich (Struthio camelus)

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2010
T. El-Mahdy
With 24 figures Summary The pelvic limb of the ostrich is innervated by the lumbar and sacral plexuses. The lumbar plexus gave rise to several nerves (N.s) including, N. coxalis cranialis, lateral and cranial femoral cutaneous N.s, N. femoralis, cranial, caudal and medial crural cutaneous N.s, and N. obturatorius. The remaining nerves emanated from the sacral plexus. The N. iliotibial, N. ischiofemoralis, N. iliofibularis, and N. coxae caudalis were distributed in the thigh, while the N. ischiadica, which terminated as the tibial and fibular N.s that innervated the leg and foot. The tibial N. gave rise to the parafibular N. then divided to form the Nn. suralis medialis and lateralis. The N. suralis medialis continued as the N. metatarsalis plantaris medialis. The parafibular N. continued as the N. plantaris lateralis, which terminated as the R. digitalis of the fourth digit. The fibular N. terminated as the superficial and deep fibular N.s. The superficial fibular N. continued as the N. metatarsalis dorsalis lateralis and divided into two digital N.s to the third and fourth digits. The deep fibular N. crossed the ankle joint and continued as the N. metatarsalis dorsalis medialis that continued as the R. digitalis of the third digit. In general, the innervation of the pelvic limb of the ostrich was similar to the pelvic limbs of several different species of domesticated birds, including the chicken. We discuss the few differences as well as appropriate sites to perform nerve blocks for the lateral and medial dorsal and the lateral plantar N.s. [source]

The Arterial Supply of the Pelvic Limb of the Adult Ostrich (Struthio camelus)

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 4 2010
S. M. El-Nahla
With 25 figures Summary Blood to the pelvic limb of the ostrich is provided by the external iliac and ischiatic arteries that arise from the descending aorta. The external iliac artery (a.) gave rise to the pubic a. that supplied the obturator muscles and continued as the femoral a. The femoral a. gave off three branches: (1) cranial coxal a. to muscles above the pre-acetabular ilium; (2) cranial femoral a. to muscles cranial to the femur, the gastrocnemius muscle, hip and stifle joints and (3) medial femoral a. to muscles caudal and medial to the femur. The ischiatic a. gave rise to the caudal coxal a. that supplied muscles caudal to the femur, muscular branches to the iliotibialis lateralis muscle and to the deep femoral a. that supplied the iliofibularis muscle, cutanea femoralis caudalis and lateralis aa., and branches to the flexors of the leg and knee joint, then terminated as the sural and popliteal arteries. The sural a. supplied most of the flexors of the foot. The popliteal a. supplied the knee joint and flexors of the leg, and then terminated as the cranial and caudal tibial arteries. The caudal tibial a. supplied flexors of the foot. The cranial tibial a. provided four branches to the knee and ankle joints and to the leg. The cranial tibial a. continued into the foot as the common dorsal metatarsal a., which gave off seven different branches to the ankle and foot. With few exceptions, the arteries of the ostrich pelvic limb are similar to those of domestic fowl. [source]

The Anatomy of the Arterial Supply of the Thoracic Limb of the Porcupine (Hystrix cristata)

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2001
Sadik Yilmaz
The aim of this study was to investigate the anatomy of the arterial supply and branches of the thoracic limb of the porcupine. With this aim, five (three male and two female) adult porcupines were used. The vascular tree of the thoracic limb was injected through the common carotid arteries with coloured latex. The a. thoracica externa arose from the a. axillaris at the level of the fourth rib. It divided into two branches and went to the m. cutaneus trunci and the m. pectoralis ascendens. The a. subscapularis came off the a. thoracodorsalis. Later, the a. circumflexa humeri caudalis et cranialis, the three muscular branches and the a. circumflexa scapulae arose from the a. subscapularis. The a. profunda brachii arose together with the a. bicipitalis from the same truncus. The a. collateralis ulnaris left from the a. brachialis independently. Rete carpi dorsale was formed by the a. radialis, the r. carpeus dorsalis of the a. collateralis ulnaris and the a. interossea caudalis. Arcus palmaris profundus was formed by the r. profundus of the a. interossea caudalis and the r. palmaris profundus of the a. radialis. In conclusion, despite a partial resemblance to that in the rat, the distribution of the thoracic limb arteries in the porcupine was found to be completely different from that of other mammals. These findings represent, to our knowledge, the first study on the distribution of thoracic limb arteries in the porcupine. [source]

Botulinum Toxin, Physical and Occupational Therapy, and Neuromuscular Electrical Stimulation to Treat Spastic Upper Limb of Children With Cerebral Palsy: A Pilot Study

ARTIFICIAL ORGANS, Issue 3 2010
Gerardo Rodríguez-Reyes
Abstract Spasticity has been successfully managed with different treatment modalities or combinations. No information is available on the effectiveness or individual contribution of botulinum toxin type A (BTA) combined with physical and occupational therapy and neuromuscular electrical stimulation to treat spastic upper limb. The purpose of this study was to assess the effects of such treatment and to inform sample-size calculations for a randomized controlled trial. BTA was injected into spastic upper limb muscles of 10 children. They received 10 sessions of physical and occupational therapy followed by 10 sessions of neuromuscular electrical stimulation on the wrist extensors (antagonist muscles). Degree of spasticity using the Modified Ashworth scale, active range of motion, and manual function with the Jebsen hand test, were assessed. Meaningful improvement was observed in hand function posttreatment (P = 0.03). Median spasticity showed a reduction trend and median amplitude of wrist range of motion registered an increase; however, neither of these were significant (P > 0.05). There is evidence of a beneficial effect of the combined treatment. Adequate information has been obtained on main outcome-measurement variability for calculating sample size for a subsequent study to quantify the treatment effect precisely. [source]

The neuromuscular junction microenvironment in extraocular and limb muscles

ACTA OPHTHALMOLOGICA, Issue 2009
F PEDROSA DOMELLOF
Purpose To characterise the components of the neuromuscular junction (NMJ) in normal and pathological extraocular muscles (EOMs) and to assess the dynamics of progressive denervation. Methods Limb and EOM samples from 11 controls,8 ALS patients and from transgenic mice with SOD1 mutations (D90A, G93A) paralleling familiar ALS were processed for immunocytochemistry with antibodies against Schwann cell markers (S-100, p75, GFAP), gangliosides GD1b and GQ1b/GT1a, neurotrophic factors (BDNF, GDNF, NT-3, NT-4) and their receptors, parvalbulmin, nestin, desmin and laminin chains. Results The NMJs of normal EOMs had a different cytoskeleton composition. Differences in the expression of gangliosides GD1b and GQ1b/GT1a, Schwann cell marker S-100, agrin and nestin at the NMJs were noted in the human ALS EOMs. Parvalbumin was absent or scarce in EOM nerve trunks of ALS patients. The analysis of the time aspects of denervation in the animal models is ongoing. Conclusion The human EOMs in late stages of ALS and the EOMs of the transgenic mice show signs of denervation, although these muscles appear remarkably well preserved. High levels of parvalbumin, proposed to be protective for oculomotor neurons in ALS, are not apparent in advanced stages of the disease. The identification of similar endpoints in the EOMs of patients with D90A mutation and the ALS transgenic mice carrying the same mutation indicates that this is a useful model to study the temporal aspects of progressive denervation in the EOMs, to explore aspects of muscle-nerve interplay that protect the EOMs in motoneuron disease and to gain further knowledge useful for the development of selective tools to modulate eye muscle function in the treatment of strabismus. [source]

Endogenous B-type Natriuretic Peptide: A Limb of the Regulatory Response to Acutely Decompensated Heart Failure

CLINICAL CARDIOLOGY, Issue 9 2008
Robert E. Hobbs MD
Abstract Acutely decompensated heart failure (ADHF) represents an episodic failure of cardiorenal homeostasis that may resolve with upregulation of natriuretic peptides, bradykinin, and certain prostacyclins. B-type natriuretic peptide (BNP) has multiple favorable effects, including vasodilation, diuresis, natriuresis, and inhibition of vascular endothelial proliferation and cardiac fibrosis. By antagonizing the effects of activation of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system in volume overload, the endogenous BNP response may help rescue patients from episodic ADHF. Although knowledge of BNP physiology is expanding, we still have limited understanding of the heterogeneity of proBNP-derived molecules, including active 32 amino acid BNP and less active junk BNP forms. Emerging evidence suggests that in ADHF, the endogenous BNP response is overwhelmed by neurohormonal activation. This relative BNP deficiency may also be accompanied by physiologic resistance to BNP. Additionally, abnormalities of BNP production may result in a lower proportion of active BNP relative to less active forms that may also be detected by point-of-care tests. Improved detection of the various BNP species may clarify these concepts and facilitate improved clinical management of ADHF. Copyright © 2008 Wiley Periodicals, Inc. [source]

Phantom Limbs and Invisible Hands: Bodies, Prosthetics, and Late Capitalist Identifications

CULTURAL ANTHROPOLOGY, Issue 3 2001
Diane M. Nelson
[source]

Serum Iron and Matrix Metalloproteinase-9 Variations in Limbs Affected by Chronic Venous Disease and Venous Leg Ulcers

DERMATOLOGIC SURGERY, Issue 6 2005
Paolo Zamboni MD
Background. Severe chronic venous disease (CVD) is characterized by both dermal hemosiderin accumulation and matrix metalloproteinase (MMP) hyperactivation. The iron-driven pathway is one of the recognized mechanisms of MMP hyperactivation. Objective. To investigate the potential consequences of leg hemosiderin deposits on both iron metabolism and activation of MMPs. Methods. We contemporaneously assessed the following in the serum of the arm and ankle veins of 30 patients (C4,6) with CVD and 14 normal subjects: ferritin, transferrin, iron, percentage of transferrin iron binding capacity (%TIBC), and MMP-9. Optical microscopy examinations with Perls' staining of chronic wounds were also performed. Results. Histology consistently revealed iron deposits. Serum ferritin, iron, and %TIBC were significantly increased in the legs affected by severe CVD compared with the arm of the same subjects or the controls. In addition, iron and %TIBC were significantly elevated in the legs of ulcer patients. The rate of activation of MMP-9 was significantly elevated in CVD. Conclusions. The increased iron deposition in legs affected by CVD seems to be more instable in ulcer patients, leading to iron release in the serum of the affected leg. Our data suggest the iron-driven pathway as a further mechanism for MMP hyperexpression leading to tissue lesion. [source]

Cutaneous melanoma in a desert climate zone: a retrospective study of 125 cases

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 4 2010
Zahra Rahnama MD
Background, With increasing incidence over the last few decades, cutaneous malignant melanoma (CM) represents 3% of all skin tumors, and accounts for 75% of all deaths because of cutaneous malignancies. Little is known about the nature and epidemiology of CM in individuals with pigmented skin. Method, Data were collected from the records of four public and private histopathology laboratories of Kerman city from March 20, 1994 to March 20, 2004. Skin biopsies with a diagnosis of CM were reevaluated to confirm the diagnosis of CM. The medical records of the patients were also taken into consideration. Results, A total of 125 CMs were found. The male-to-female ratio was 1.08 : 1. The mean age at the time of diagnosis was 58.9 years; with a peak in the seventh decade of life. Acral-lentiginous melanoma (ALM) represented 28.8% and; nodular melanoma occurred in 20% of cases. Limbs were the site of occurrence in 44% of tumors; whereas 36% of tumors occurred in head and neck region. There was a significant correlation between age and ALM (P = 0.007) and also between gender and melanoma types (P = 0.024). Conclusions, This study indicates that some demographic and histopathologic features of CM in this population differ from those in the literature. More studies including cohort studies are needed to fully describe the nature and survival rate of CM in this area. [source]

Residual Limbs of Amputees Are Significantly Cooler than Contralateral Intact Limbs

PAIN PRACTICE, Issue 5 2008
R. Norman Harden MD
,,Abstract: Objective: To test the hypothesis that distal residual limbs (DRLs) have significant vasomotor abnormalities. Design: Comparative surface temperature studies of DRLs using paired samples (DRL vs. similar site on intact contralateral limb). Subjects/Patients: Thirty-six volunteer subjects with unilateral, upper or lower limb amputations were recruited and evaluated at a pain research center in an urban academic rehabilitation facility. Methods: Our main outcomes were subjects' residual limb temperature as measured by quantitative infrared telethermography (qIRT), temperature strips, and examiner's palpation, compared with the contralateral limb. Results: The qIRT showed that the DRLs were significantly cooler than the corresponding area of the contralateral intact limbs (P < 0.01). The difference using temperature strips supported this finding (P < 0.05); while on physical examination, 39% of the residual limbs were perceived by the examiner as cooler than the corresponding unaffected limbs. Conclusions: DRLs as measured by qIRT were significantly cooler than the corresponding area of the contralateral intact limbs. A better understanding of these findings may be important in elucidating the pathophysiology of relevant clinical features such as a potential sympathetic component of postamputation pain.,, [source]

Muscle metaboreflex control of the circulation during exercise

ACTA PHYSIOLOGICA, Issue 4 2010
R. Boushel
Abstract This review covers the control of blood pressure, cardiac output and muscle blood flow by the muscle metaboreflex which involves chemically sensitive nerves located in muscle parenchyma activated by metabolites accumulating in the muscle during contraction. The efferent response to metaboreflex activation is an increase in sympathetic nerve activity that constricts the systemic vasculature and also evokes parallel inotropic and chronotropic effects on the heart to increase cardiac output. The metaboreflex elicits a significant blood pressure elevating response during exercise and functions to redistribute blood flow and blood volume. Regional specificity in the efferent response to the metaboreflex activated from either the leg or the arm is seen in the balance between signals for vasoconstriction to curtail blood flow and signals to increase cardiac output. The metaboreflex has dual functions. It can both elevate and decrease muscle blood flow depending on (1) the intensity and mode of contraction, (2) the limb in which the reflex is evoked, (3) the strength of the signal defined by the muscle mass, (4) the extent to which blood flow is redistributed from inactive vascular beds to increase central blood volume and (5) the extent to which cardiac output can be increased. [source]

Localization and functional characterization of the human NKCC2 isoforms

ACTA PHYSIOLOGICA, Issue 3 2010
I. Carota
Abstract Aim:, Salt reabsorption across the apical membrane of cells in the thick ascending limb (TAL) of Henle is primarily mediated by the bumetanide-sensitive Na+/K+/2Cl, cotransporter NKCC2. Three full-length splice variants of NKCC2 (NKCC2B, NKCC2A and NKCC2F) have been described. The NKCC2 isoforms have specific localizations and transport characteristics, as assessed for rabbit, rat and mouse. In the present study, we aimed to address the localization and transport characteristics of the human NKCC2 isoforms. Methods:, RT-PCR, in situ hybridization and uptake studies in Xenopus oocytes were performed to characterize human NKCC2 isoforms. Results:, All three classical NKCC2 isoforms were detected in the human kidney; in addition, we found splice variants with tandem duplicates of the variable exon 4. Contrary to rodents, in which NKCC2F is the most abundant NKCC2 isoform, NKCC2A was the dominant isoform in humans; similarly, isoform-specific in situ hybridization showed high expression levels of human NKCC2A along the TAL. Compared to NKCC2B and NKCC2F, human NKCC2A had the lowest Cl, affinity as determined by 86Rb+ uptake studies in oocytes. All NKCC2 isoforms were more efficiently inhibited by bumetanide than by furosemide. A sequence analysis of the amino acids encoded by exon 4 variants revealed high similarities between human and rodent NKCC2 isoforms, suggesting that differences in ion transport characteristics between species may be related to sequence variations outside the highly conserved sequence encoded by exon 4. Conclusion:, The human NKCC2 is an example of how differential splicing forms the basis for a diversification of transporter protein function. [source]

Potential Effects of Passenger Pigeon Flocks on the Structure and Composition of Presettlement Forests of Eastern North America

CONSERVATION BIOLOGY, Issue 6 2003
JOSHUA W. ELLSWORTH
We suggest that the activities of roosting and nesting Passenger Pigeons caused widespread, frequent disturbances in presettlement eastern forests through tree limb and stem breakage and nutrient deposition from pigeon excrement. We suspect that the deposition of fine fuels resulting from such disturbances may have influenced fire intensity and frequency in presettlement forests. Further, we propose that consumption of vast quantities of acorns by pigeons during the spring breeding season may partially explain the dominance of white oak (Quercus alba) throughout much of the presettlement north-central hardwoods region. Consequently, the pigeon's extinction may have facilitated the increase and expansion of northern red oak (Quercus rubra) during the twentieth century. Although it is difficult to accurately quantify how physical and chemical disturbances and mast consumption by Passenger Pigeon flocks affected forest ecology, we suspect they shaped landscape structure and species composition in eastern forests prior to the twentieth century. We believe their impact should be accounted for in estimates of the range of natural variability of conditions in eastern hardwood forests. Resumen:,Consideramos los posibles efectos que pudieron haber tenido parvadas de Palomas Migratorias (Ectopistes migratorius) sobre el régimen de perturbación y la composición de especies de bosques en Norte América oriental antes de la colonización. Sugerimos que las actividades de perchado y anidación de las palomas causaron perturbaciones frecuentes y extensas en los bosques orientales antes de la colonización por medio de la ruptura de ramas y tallos de árboles y la deposición de nutrientes del excremento de las palomas. Sospechamos que la deposición de combustibles resultantes de tales perturbaciones pudo haber influido en la intensidad y frecuencia de incendios forestales. Más aún, proponemos que el consumo de grandes cantidades de bellotas por las palomas en la primavera puede parcialmente explicar la dominancia de roble blanco (Quercus alba) en muchos de los bosques nor-orientales. En consecuencia, la extinción de la paloma pudo haber facilitado el incremento y expansión del roble rojo (Quercus rubra) durante el siglo veinte. Aunque es difícil cuantificar con precisión como las perturbaciones físicas y químicas y el consumo masivo por parvadas de palomas migratorias afectaron a la ecología forestal, sospechamos que modelaron la estructura del paisaje y la composición de especies en los bosques orientales antes del siglo veinte. Creemos que su impacto debería ser considerado cuando se hacen estimaciones del rango de variabilidad natural de las condiciones en bosques orientales de maderas duras. [source]

The role of inhibitory neurotransmission in locomotor circuits of the developing mammalian spinal cord

ACTA PHYSIOLOGICA, Issue 2 2009
H. Nishimaru
Abstract Neuronal circuits generating the basic coordinated limb movements during walking of terrestrial mammals are localized in the spinal cord. In these neuronal circuits, called central pattern generators (CPGs), inhibitory synaptic transmission plays a crucial part. Inhibitory synaptic transmission mediated by glycine and GABA is thought to be essential in coordinated activation of muscles during locomotion, in particular, controlling temporal and spatial activation patterns of muscles of each joint of each limb on the left and right side of the body. Inhibition is involved in other aspects of locomotion such as control of speed and stability of the rhythm. However, the precise roles of neurotransmitters and their receptors mediating inhibitory synaptic transmission in mammalian spinal CPGs remain unclear. Moreover, many of the inhibitory interneurones essential for output pattern of the CPG are yet to be identified. In this review, recent advances on these issues, mainly from studies in the developing rodent spinal cord utilizing electrophysiology, molecular and genetic approaches are discussed. [source]

The adaptive responses in several mediators linked with hypertrophy and atrophy of skeletal muscle after lower limb unloading in humans

ACTA PHYSIOLOGICA, Issue 2 2009
K. Sakuma
Abstract Aim:, To determine the adaptive changes in several molecules regulating muscle hypertrophy and atrophy after unloading, we examined whether unilateral lower limb suspension changes the mRNA and protein levels of SRF-linked (RhoA, RhoGDI, STARS and SRF), myostatin-linked (myostatin, Smad2, Smad3 and FLRG) and Foxo-linked (P-Akt, Foxo1, Foxo3a and Atrogin-1) mediators. Methods:, A single lower limb of each of eight healthy men was suspended for 20 days. Biopsy specimens were obtained from the vastus lateralis muscle pre- and post-suspension. Results:, The volume of the vastus lateralis muscle was significantly decreased after unloading. The amount of RhoA, RhoGDI or SRF protein in the muscle was not significantly changed post-suspension. An RT-PCR semiquantitative analysis showed increased levels of myostatin mRNA but not Smad2, Smad3 or FLRG mRNA. Unloading did not elicit significant changes in the amount of p-Smad3 or myostatin protein in the muscle. The amount of p-Akt protein was markedly reduced in the unloaded muscle. Lower limb suspension did not influence the expression pattern of Foxo1, Foxo3a or Atrogin-1. Conclusion:, Unloading inducing a mild degree of muscle atrophy may decrease p-Akt and increase myostatin but not SRF-linked mediators. [source]

Does limb angular motion raise limb arterial pressure?

ACTA PHYSIOLOGICA, Issue 3 2009
D. D. Sheriff
Abstract Aim:, Mechanical factors such as the muscle pump have been proposed to augment flow by several mechanisms. The potential for limb angular motion to augment local perfusion pressure (pressure = ½,r2,2, where , is the fluid density, r the radius and , the angular velocity) has been overlooked. We sought to test the hypothesis that limb angular motion augments limb arterial pressure. Methods:, Nine human subjects performed horizontal shoulder flexion (,±90° at 0.75 Hz for 30 s). We measured finger arterial pressure (photoplethysmography) in the moving (Trial 1) and non-moving arm (Trial 2) in separate trials along with the pressure (strain gauge) generated at the fingers within a length of water-filled tubing mounted on the moving arm in both trials. Results:, Arm swinging raised (P < 0.05) the mean pressure measured in the tubing by 11 ± 2 and 14 ± 2 mmHg (Trials 1 and 2 respectively). In response to exercise, the rise in mean finger arterial pressure in the swinging limb (18 ± 3 mmHg, Trial 1) exceeded (P < 0.05) the rise in the resting limb (8 ± 2 mmHg, Trial 2) by an amount similar to the 11 mmHg rise in pressure generated in the tubing in Trial 1. Conclusions:, We conclude that the swinging of a limb creates centrifugal force (a biomechanical centrifuge) which imparts additional pressure to the arteries, but not the veins owing to the venous valves, which further widens the arterial,venous pressure difference. [source]

Losartan decreases vasopressin-mediated cAMP accumulation in the thick ascending limb of the loop of Henle in rats with congestive heart failure

ACTA PHYSIOLOGICA, Issue 4 2007
M. Torp
Abstract Introduction:, Vasopressin (AVP) stimulates sodium reabsorption and Na,K,2Cl-cotransporter (NKCC2) protein level in the thick ascending limb (TAL) of Henle's loop in rats. Rats with congestive heart failure (CHF) have increased protein level of NKCC2, which can be normalized by angiotensin II receptor type-1 (AT1) blockade with losartan. Aim:, In this study, we investigated whether CHF rats displayed changes in AVP stimulated cAMP formation in the TAL and examined the role of AT1 receptor blockade on this system. Method:, CHF was induced by ligation of the left anterior descending coronary artery (LAD). SHAM-operated rats were used as controls. Half of the rats were treated with losartan (10 mg kg day,1 i.p.). Results:, CHF rats were characterized by increased left ventricular end diastolic pressure. Measurement of cAMP in isolated outer medullary TAL showed that both basal and AVP (10,6 m) stimulated cAMP levels were significantly increased in CHF rats (25.52 ± 4.49 pmol cAMP ,g,1 protein, P < 0.05) compared to Sham rats (8.13 ± 1.14 pmol cAMP ,g,1 protein), P < 0.05). Losartan significantly reduced the basal level of cAMP in CHF rats (CHF: 12.56 ± 1.93 fmol ,g,1 protein vs. Los-CHF: 7.49 ± 1.08, P < 0.05), but not in Sham rats (SHAM: 4.66 ± 0.59 vs. Los-SHAM: 4.75 ± 0.71). AVP-mediated cAMP accumulation was absent in both groups treated with losartan (Los-SHAM: 4.75 ± 0.71 and Los-CHF: 7.49 ± 1.08). Conclusion:, The results indicate that the increased NKCC2 protein level in the mTAL from CHF rats is associated with increased cAMP accumulation in this segment. Furthermore, the finding that AT1 receptor blockade prevents AVP-mediated cAMP accumulation in both SHAM and CHF rats suggests an interaction between angiotensin II and AVP in regulation of mTAL Na reabsorption. [source]

Reversible Cardiac Arrest After Polidocanol Sclerotherapy of Peripheral Venous Malformation

DERMATOLOGIC SURGERY, Issue 2 2002
Massimiliano M. Marrocco-Trischitta MD
background. Polidocanol sclerotherapy is a well-established therapeutic modality for the treatment of venous malformations. Systemic complications are extremely rare. objective. To report a case of cardiac complication after polidocanol injection of peripheral venous malformation. methods. A case report and a review of the English language literature using a published MEDLINE search strategy. results. A patient undergoing polidocanol sclerotherapy for a symptomatic venous malformation of the right inferior limb developed cardiac arrest shortly after injection of the sclerosing agent which was promptly reversed. conclusion. Systemic complications following sclerotherapy may occur even when the sclerosant is injected in peripheral veins or venous malformations. Clinicians should be alerted to the possibility of uncommon but life-threatening adverse effects. [source]

Dermal fibroblasts contribute to multiple tissues in the accessory limb model

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 4 2010
Ayako Hirata
The accessory limb model has become an alternative model for performing investigations of limb regeneration in an amputated limb. In the accessory limb model, a complete patterned limb can be induced as a result of an interaction between the wound epithelium, a nerve and dermal fibroblasts in the skin. Studies should therefore focus on examining these tissues. To date, however, a study of cellular contributions in the accessory limb model has not been reported. By using green fluorescent protein (GFP) transgenic axolotl tissues, we can trace cell fate at the tissue level. Therefore, in the present study, we transgrafted GFP skin onto the limb of a non-GFP host and induced an accessory limb to investigate cellular contributions. Previous studies of cell contribution to amputation-induced blastemas have demonstrated that dermal cells are the progenitors of many of the early blastema cells, and that these cells contribute to regeneration of the connective tissues, including cartilage. In the present study, we have determined that this same population of progenitor cells responds to signaling from the nerve and wound epithelium in the absence of limb amputation to form an ectopic blastema and regenerate the connective tissues of an ectopic limb. Blastema cells from dermal fibroblasts, however, did not differentiate into either muscle or neural cells, and we conclude that dermal fibroblasts are dedifferentiated along its developmental lineage. [source]

How to make a zone of polarizing activity: Insights into limb development via the abnormality preaxial polydactyly

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2007
Robert E. Hill
Early in vertebrate limb development, a program initiates that polarizes the limb along the antero-posterior axis. The mesenchyme at the posterior margin is ultimately responsible for the asymmetry due to a region called the zone of polarizing activity (ZPA). The ZPA produces and secretes the molecule SHH, which coordinates the patterning of the resulting digits. Preaxial polydactyly (PPD) is a commonly occurring limb abnormality; investigating the genetic basis of this defect has provided insights into our understanding of digit patterning. PPD disrupts limb asymmetry by producing an ectopic ZPA at the opposite margin of the limb bud. Mutations in the long-range, limb-specific regulatory element of the Shh gene are responsible for the defect. Genetic analysis of this limb abnormality provides an important approach in understanding the mechanisms that control digit patterning. [source]

Insulin-like growth factors, hepatocyte growth factor and transforming growth factor-, in mouse tongue myogenesis

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2003
Akira Yamane
Many reports have shown that tongue striated muscles have several unique characteristics not found in other skeletal muscles such as limb and trunk. Several peptide growth factors are reported to play important roles in skeletal myogenesis. In this article, the roles of insulin-like growth factors (IGF), hepatocyte growth factor (HGF) and transforming growth factor (TGF)-, in mouse tongue myogenesis were studied using an organ culture system of the mandible or tongue obtained from mouse embryos. It was found that IGF-I promotes the differentiation of tongue myoblasts. HGF plays an essential role in the migration and proliferation of tongue myogenic cells, and inhibits the differentiation of tongue myoblasts. TGF-, does not play an essential role in the proliferation of tongue myogenic cells, but does promote the early differentiation of tongue myoblasts. The role of IGF-I in the differentiation of tongue myoblasts, and that of HGF in the migration, proliferation and differentiation of tongue myogenic cells appear to be almost identical to their roles in the myogenesis of limb and cultured myogenic cell lines. However, the role of TGF-, in the proliferation and differentiation of tongue myogenic cells appears to be different from its role in the myogenesis of limb and cultured myogenic cell lines such as C2 and L6. [source]

Effects of activation of hedgehog signaling on patterning, growth, and differentiation in Xenopus froglet limb regeneration

DEVELOPMENTAL DYNAMICS, Issue 8 2009
Nayuta Yakushiji
Abstract Regenerating limbs of urodele amphibians and Xenopus tadpole are reconstructed along proximal,distal, anterior,posterior (AP), and dorsal,ventral axes. In contrast, a regenerated limb of the Xenopus froglet does not have digits, and only a simple cartilaginous structure referred to as a "spike" is formed. This suggests that repatterning along the AP axis is absent in the froglet blastema. Previous studies have shown that Shh and its target genes are not expressed in the froglet blastema. In this study, we activated Hedgehog signaling in the froglet blastema and found that target genes of Shh were inducible in the mesenchyme of limb blastema. Furthermore, we found that activation of the signaling had effects on blastema cell proliferation and chondrogenesis and resulted in the formation of multiple cartilaginous structures. These findings indicate that activation of signaling that is absent in the froglet blastema is effective for improvement of limb regeneration ability in the Xenopus froglet. Developmental Dynamics, 2009. © 2009 Wiley-Liss, Inc. [source]

Beyond early development: Xenopus as an emerging model for the study of regenerative mechanisms

DEVELOPMENTAL DYNAMICS, Issue 6 2009
Caroline W. Beck
Abstract While Xenopus is a well-known model system for early vertebrate development, in recent years, it has also emerged as a leading model for regeneration research. As an anuran amphibian, Xenopus laevis can regenerate the larval tail and limb by means of the formation of a proliferating blastema, the lens of the eye by transdifferentiation of nearby tissues, and also exhibits a partial regeneration of the postmetamorphic froglet forelimb. With the availability of inducible transgenic techniques for Xenopus, recent experiments are beginning to address the functional role of genes in the process of regeneration. The use of soluble inhibitors has also been very successful in this model. Using the more traditional advantages of Xenopus, others are providing important lineage data on the origin of the cells that make up the tissues of the regenerate. Finally, transcriptome analyses of regenerating tissues seek to identify the genes and cellular processes that enable successful regeneration. Developmental Dynamics 238:1226,1248, 2009. © 2009 Wiley-Liss, Inc. [source]

All- trans retinoic acid-induced ectopic limb and caudal structures: Murine strain sensitivities and pathogenesis

DEVELOPMENTAL DYNAMICS, Issue 6 2008
Xiaoyan Liao
Abstract Treatment of pregnant mice at the egg cylinder stage with retinoic acid (RA) has caused ectopic hindlimbs in the offspring. Proposed causes of ectopic hindlimbs include homeotic transformation or multiple axis formation. Two mouse strains were determined to be divergent in susceptibility to this malformation (C57BL/6N, highly sensitive; SWV/Fnn, less sensitive). Ectopic limbs were hindlimbs (expressing Pitx1 and Tbx4 but not Tbx5), yet they also expressed the predominantly forelimb Hoxb8. Ectopic body axis formation was indicated by gene expression for ectopic primitive streaks, notochords, and nodes, as well as inhibition of anterior visceral endoderm and mesodermal migration. The earlier in development that embryos were examined, the higher the rate of ectopic hindlimb development and axis formation. Ectopic axis formation and cell migration inhibition had the same strain susceptibility as the dysmorphogenesis. We propose that all extra hindlimbs were derived from ectopic axis formation, perturbation of which is genetic background dependent. Developmental Dynamics 237:1553,1564, 2008. © 2008 Wiley-Liss, Inc. [source]

The development of several organs and appendages is impaired in mice lacking Sp6

DEVELOPMENTAL DYNAMICS, Issue 4 2008
Valérie Hertveldt
Abstract SP6 belongs to the SP/KLF family of transcription factors, characterized by a DNA-binding domain composed of three zinc fingers of the C2H2 type. The Sp6 gene generates two different transcripts, termed Sp6 and epiprofin, which differ in the first exon and encode the same SP6 protein. These transcripts are mainly expressed in the skin, the teeth, and the limb buds of embryos and also in the adult lungs. To gain insight into the biological function of the SP6 protein, we knocked out the gene by eliminating the full coding region. The resulting Sp6 null mice are nude, lack functional teeth, and present limb and lung malformations. We also showed that the identified abnormalities are associated with apoptotic misregulations. In conclusion, this work indicates that Sp6 plays a critical role in the development of several epithelium-containing organs or appendages, possibly by regulating apoptosis. Developmental Dynamics 237:883,892, 2008. © 2008 Wiley-Liss, Inc. [source]

Expression of the NET family member Zfp503 is regulated by hedgehog and BMP signaling in the limb

DEVELOPMENTAL DYNAMICS, Issue 4 2008
Edwina McGlinn
Abstract The NET/Nlz family of zinc finger transcription factors contribute to aspects of developmental growth and patterning across evolutionarily diverse species. To date, however, these molecules remain largely uncharacterized in mouse and chick. We previously reported that limb bud expression of Zfp503, the mouse orthologue of zebrafish nlz2/znf503, is dependent on Gli3. Here, we show that Zfp503/Znf503 is expressed in a restricted pattern during mouse and chick embryogenesis, with particularly dynamic expression in the developing limbs, face, somites, and brain. We also add to our previous data on Gli3 regulation by showing that the anterior domain of Zfp503 expression in the mouse limb is responsive to genetic and nongenetic manipulation of hedgehog signaling. Finally, we demonstrate that posterior expression of Znf503 in the chick limb is responsive to bone morphogenetic protein (BMP) signaling, indicating that Zfp503/Znf503 may act at the nexus of multiple signaling pathways in development. Developmental Dynamics 237:1172,1182, 2008. © 2008 Wiley-Liss, Inc. [source]