Crural Regions Research Articles

The brain of the tree pangolin (Manis tricuspis). X. The spinal cord.

The spinal cord of the tree pangolin is known to be very short compared to the overall length of the body and tail. Here, we provide a description of the tree pangolin spinal cord to determine whether the short length contributes to specific structural, and potentially functional, differences. The short spinal cord of the adult tree pangolin, at around 13 cm, terminates at the midthoracic level. Within this shortened spinal cord, we could identify six regions, which from rostral to caudal include the prebrachial, brachial, interramal, crural, postcrural, and caudal regions, with both the brachial and crural regions showing distinct swellings. The chemoarchitecture of coronal sections through these regions confirmed regional assignation, being most readily delineated by the presence of cholinergic neurons forming the intermediolateral column in the interramal region and the sacral parasympathetic nucleus in the postcrural region. The 10 laminae of Rexed were observed throughout the spinal cord and presented with an anatomical organization similar to that observed in other mammals. Despite the shortened length of the tree pangolin spinal cord, the regional and laminar anatomical organization is very similar to that observed in other mammals. This indicates that the functional aspects of the short tree pangolin spinal cord can be inferred from what is known in other mammals.

Morphometric analysis and three-dimensional computed tomography reconstruction of the long bones of femoral and crural regions in Van cats.

This study was conducted to determine the morphometric features and to make the three-dimensional (3D) reconstruction of the images obtained by computed tomography (CT) of the main long bones (femur, tibia, fibula) in Van cats, and to reveal the biometric differences between these measurement values of both sexual dimorphism and homotypic variations. A total of 16 adult Van cats, 8 male and 8 female, were used in the study. The pelvic limb long bones of the cats, which were anesthetized with the ketamine-xylazine combination, were scanned with a CT device and their images were obtained. These images were converted to a 3D structure by means of MIMICS 20.1 (The Materialise Group, Leuven, Belgium) software programme. Then, morphometric, volumetric, surface arae measurements of these bones were calculated and statistical analyses were performed. In the analysis, it was observed that right greatest length (GL), left GL, right greatest length from caput ossis femoris (GLc), left greatest breadth of the distal end (Bd), right volume (V), and left V measurement values of the femur; left GL1, right greatest breadth of the proximal end (Bp), right Bd, left Bd, right smallest breadth of the diaphysis (SD), right V, left V, and right surface area (SA) measurement values of the tibia; right V, left V, right SA, and left SA measurement values of the fibula were statistically significantly higher in male cats than in female cats (p < 0.05). The volume and surface area measurement values of the femur, tibia and fibula of male and female cats were determined as 8.57 ± 1.33 cm3 and 7.00 ± 0.49 cm3, 64.28 ± 6.72 cm2 and 59.42 ± 4.72 cm2; 7.56 ± 1.28 cm3 and 6.15 ± 0.52 cm3, 56.89 ± 6.47 cm2 and 52.72 ± 3.15 cm2; 1.10 ± 0.17 cm3 and 0.83 ± 0.05 cm3, 14.18 ± 1.61 cm2 and 11.95 ± 0.48 cm2, respectively. The statistical differences between the sexes in terms of the measurement parameters of the femur, tibia and fibula in adult Van cats were determined. We believe that these differences can be used in determining morphological variations of Van cats. In addition, it is thought that the data obtained from the present study would be beneficial to veterinary physicians in the clinical application areas in order to evaluate the pathological conditions related to these bones and to the studies in the field of zooarchaeology.

Diagnostic ultrasound assessment of deep fascia sliding mobility in vivo: A scoping review – Part 2: Femoral and crural fasciae

BackgroundFailure of fascial sliding may occur in cases of excessive or inappropriate use, trauma, or surgery, resulting in local inflammation, pain, sensitization, and potential dysfunction. Therefore, the mechanical properties of fascial tissues, including their mobility, have been evaluated in vivo by ultrasound (US) imaging. However, this seems to be a method that is not yet properly standardized nor validated. ObjectivesTo identify, synthesize, and collate the critical methodological principles that have been described in the literature for US evaluation of deep fascia sliding mobility in vivo in humans. MethodsA systematic literature search was conducted on ScienceDirect, PubMed (Medline), Web of Science and B-On databases, according to the PRISMA Extension for Scoping Reviews (PRISMA-ScR) guidelines. The OCEBM LoE was used to evaluate the level of evidence of each study. ResultsFrom a total of 104 full-text articles retrieved and assessed for eligibility, 18 papers were included that evaluate the deep fasciae of the thoracolumbar (n = 4), abdominal (n = 7), femoral (n = 4) and crural (n = 3) regions. These studies addressed issues concerning either diagnosis (n = 11) or treatment benefits (n = 7) and presented levels of evidence ranging from II to IV. Various terms were used to describe the outcome measures representing fascial sliding. Also, different procedures to induce fascial sliding, positioning of the individuals being assessed, and features of US devices were used. The US analysis methods included the comparison of start and end frames and the use of cross-correlation software techniques through automated tracking algorithms. These methods had proven to be reliable to measure sliding between TLF, TrA muscle-fascia junctions, fascia lata, and crural fascia, and the adjacent epimysial fascia. However, the papers presented heterogeneous terminologies, research questions, populations, and methodologies.This two-part paper reviews the evidence obtained for the thoracolumbar and abdominal fasciae (Part 1) and for the femoral and crural fasciae (Part 2). ConclusionThe US methods used to evaluate deep fascia sliding mobility in vivo in humans include the comparison of start and end frames and the use of cross-correlation software techniques through automated tracking algorithms. These seem reliable methods to measure sliding of some fasciae, but more studies need to be systematized to confirm their reliability for others. Moreover, specific standardized protocols are needed to assess each anatomical region as well as study if age, sex-related characteristics, body composition, or specific clinical conditions influence US results.

Identificação de pontos seguros para injeção intramuscular na região femoral de cães SRD

Aiming to demystify intramuscular injection into the lateral femoral region, which, according to some authors is a technique that can lead to injury of the sciatic nerve, held the anatomical study of the femoral region. Thus, we used ten mongrel dogs of different sizes, age and sex, fixed in formaldehyde solution 10%. We identified the visible and palpable bony projections of gluteal, femoral and crural regions. Dissection of these regions, identifying the muscles, vessels and nerves of the lateral surface. With a syringe containing dye was injected a small quantities in various parts of the lateral femoral region observing the proximity of the points marked with sciatic nerve. It was observed that the sciatic nerve protruded deep into the center of the distance between the imaginary lines drawn from the greater trochanter of the femur to the lateral condyle of the tibia and the ischial tuberosity to the lateral condyle of the tibia. It was concluded that intramuscular injection in the lateral femoral region is safe, since respect that line, and that the most suitable intramuscular injection would beat the center of an imaginary line drawn from the ischial tuberosity to the lateral condyle of the tibia, without risk of injury sciatic nerve.

First-Pass and High-Resolution Steady-State Magnetic Resonance Angiography of the Peripheral Arteries With Gadobenate Dimeglumine

To assess the feasibility of combined first-pass (FP) and steady-state (SS) contrast-enhanced magnetic resonance angiography (MRA) of the peripheral arteries with gadobenate dimeglumine (MultiHance) and to evaluate diagnostic performance relative to digital subtraction angiography (DSA). A total of 35 patients with symptomatic peripheral arterial occlusive disease (PAOD) underwent FP MRA (repetition time [TR]/echo time [TE]/flip angle [FA]/acquisition time [TA] = 3.5/1.2/30°/14s) at 1.5T after intravenous injection of 10 mL of gadobenate dimeglumine. Thereafter, SS imaging of the calf (TR/TE/FA/TA = 7.5/2.3/20°/40-130s) and femoropopliteal (TR/TE/FA/TA = 7.5/2.3/18°/130-240s) regions was performed after a second injection of 5 mL of gadobenate dimeglumine. All patients underwent conventional DSA. Three readers reviewed separate FP and FP+SS MRA datasets for image quality and presence/absence of clinically relevant PAOD. A fourth independent observer evaluated DSA images. The diagnostic performance (sensitivity, specificity, positive and negative predictive values) achieved with each dataset was determined and compared. Inter-reader agreement was assessed using kappa statistics. The image quality of 134 of 140 vascular regions was optimal or adequate on SS MRA. Inter-reader agreement was good to very good for assessments of FP (κ = 0.725) and combined FP+SS images (κ = 0.866). SS images improved diagnostic confidence in 34 (48.6%) femoropoliteal and 46 (65.7%) crural regions and altered final diagnosis in 8 (11.4%) and 10 (14.3%) regions, respectively. Global diagnostic accuracy increased from 92.9% on FP images to 95.9% on FP+SS images, with significant (P = 0.0384) improvement in the crural region. SS MRA of the peripheral arteries is feasible with gadobenate dimeglumine and potentially improves diagnostic performance in patients with symptomatic PAOD.

Pyoderma gangrenosum treated successfully with visilizumab in patients with ulcerative colitis

Pyoderma gangrenosum is a misleading designation for an idiopathic ulcerating cutaneous disease. The activity of pyoderma gangrenosum may or may not follow the activity of the inflammatory bowel disease. Visilizumab (Nuvion, PDL Bio Pharma, USA), a humanized IgG2 monoclonal antibody that binds to the human CD3 epsilon chain expressed on human T cells, induces the rapid production of selective chemokines, and reduces the CXCR3-mediated chemotaxis of the resting peripheral blood lymphocytes. In activated, but not resting T cells, visilizumab leads to rapid apoptosis. During a period of 20 years, a 40-year-old male took part in more than 30 courses of treatment for a dermatological condition misdiagnosed as crural eczema, mycosis and infected wounds. This ulcerative process was very severe in both crural regions. Ulcerative colitis was diagnosed a decade ago. He has been steroid-dependent since 1997. In 2005, pyoderma gangrenosum was diagnosed. In 2006, the patient participated in the visilizumab study and received 2x375 mcg study drug (5 mcg/kg/dose) intravenously. Six months after visilizumab administration, his leg ulcers healed. After the administration of visilizumab, pyoderma gangrenosum had not relapsed. In this severe pyoderma case, visilizumab also treated the skin disease. Although the colitis later worsened, the pyoderma gangrenosum has not recurred to date in this steroid-dependent patient. Pyoderma gangrenosum may be a T cell-mediated disease. The fact that biological therapy proved dramatically effective in this patient may suggest the use of these agents as first line of therapy in such cases.

Widespread, chronic, and fluconazole‐resistant Trichophyton rubrum infection in an immunocompetent patient

Chronic, widespread and invasive cutaneous dermatophytoses due to Trichopyhton rubrum are common in immunocompromised patients. In immunocompetent individuals, however, chronic widespread dermatophytoses are more often associated with onychomycosis and tinea pedis. We describe a 54-year-old immunocompetent female who presented with a 2-year history of extensive erythematous and hyper-pigmented scaly plaques involving the abdominal, gluteal and crural regions without concomitant tinea pedis, tinea manus or onychomycosis. The diagnosis was made by mycological examination including culture. The pathogen identified was T. rubrum. The patient had a history of resistance to systemic fluconazole and topical ketoconazole. After an 8-week therapy period with systemic itraconazole and sertaconazole nitrate cream, a near-complete clearing of all lesions was observed. Trichophyton rubrum may thus present atypical aspects in immmunocompetent patients.

Unusual presentation of tinea cruris due to Trichophyton mentagrophytes var. mentagrophytes

Tinea cruris is a subacute or chronic dermatophytosis. This report describes a 30-year-old man presenting with a history of bullous erythematous along with itching of his crural regions. On the basis of clinical findings, the lesions were diagnosed as contact dermatitis and pustular psoriasis, so he was treated by local and systemic corticosteroids but pustular lesions were progressed on the affected sites. By using mycological and histological examinations, dermatophytosis caused by Trichophyton mentagrophytes var. mentagrophytes was confirmed. The patient was successfully treated with itraconazole and local antifungal treatments.

Effects of spaceflight on myosin heavy-chain content, fibre morphology and succinate dehydrogenase activity in rat diaphragm.

The present study examined the effect of 14 days of exposure to microgravity during the Spacelab Life Sciences-2 (SLS-2) space shuttle mission on the myosin heavy-chain (MHC) content, fibre size and type distributions and metabolic properties of rat diaphragm. Five adult male Sprague-Dawley rats were exposed to 14 days of microgravity (SF, spaceflight) and compared to five ground-based controls (C). Immunohistochemical analyses using isoform-specific anti-MHC monoclonal antibodies revealed that 14 days of SF did not alter the proportions of type-I, -IIA, -IID/X or -IIB fibres within the crural, sternal or lateral costal regions of the diaphragm; the electrophoretically quantified MHC-isoform contents also remained unchanged. In contrast, the medial gastrocnemius (MG) and tibialis anterior (TA) muscles displayed slow-to-fast fibre type transitions: within the MG the proportion of type-IID/X fibres was reduced by 59% ( P<0.04) and corresponded to a 51% increase ( P<0.03) in type-IIB fibres. Within the TA, the sum of type-IID/X+IIB fibres was elevated by 24% ( P<0.02) at the expense of the slower type-IIA fibres, which decreased by 33% ( P<0.04). Electrophoretic analyses yielded qualitatively similar patterns of transformation. SF did not induce atrophic changes within the diaphragm, MG or TA. Succinate dehydrogenase activity remained unchanged in the crural diaphragm ( P>0.96) but was 34% lower ( P<0.0001) in the TA. We conclude that 14 days of SF did not alter structural or metabolic factors that are known to underlie functional properties of the diaphragm. The findings of the present study show that 14 days of SF does not induce deleterious adaptive changes in the rat diaphragm that occur in hindlimb muscles.

Inferences on force transmission from muscle fiber architecture of the canine diaphragm.

Functional properties of the diaphragm are mediated by muscle structure. Modeling of force transmission necessitates a precise knowledge of muscle fiber architecture. Because the diaphragm experiences loads both along and transverse to the long axes of its muscle fibers in vivo, the mechanism of force transmission may be more complex than in other skeletal muscles that are loaded uniaxially along the muscle fibers. Using a combination of fiber microdissections and histological and morphological methods, we determined regional muscle fiber architecture and measured the shape of the cell membrane of single fibers isolated from diaphragm muscles from 11 mongrel dogs. We found that muscle fibers were either spanning fibers (SPF), running uninterrupted between central tendon (CT) and chest wall (CW), or were non-spanning fibers (NSF) that ended within the muscle fascicle. NSF accounted for the majority of fibers in the midcostal, dorsal costal, and lateral crural regions but were only 25-41% of fibers in the sternal region. In the midcostal and dorsal costal regions, only approximately 1% of the NSF terminated within the fascicle at both ends; the lateral crural region contained no such fibers. We measured fiber length, tapered length, fiber diameters along fiber length, and the taper angle for 271 fibers. The lateral crural region had the longest mean length of SPF, which is equivalent to the mean muscle length, followed by the costal and sternal regions. For the midcostal and crural regions, the percentage of tapered length of NSF was 45.9 +/- 5.3 and 40.6 +/- 7.5, respectively. The taper angle was approximately 0.15 degrees for both, and, therefore, the shear component of force was approximately 380 times greater than the tensile component. When the diaphragm is submaximally activated, as during normal breathing and maximal inspiratory efforts, muscle forces could be transmitted to the cell membrane and to the extracellular intramuscular connective tissue by shear linkage, presumably via structural transmembrane proteins.

The etiology and epidemiology of dermatophytoses in Goiânia, GO, Brazil

Dermatophytoses are superficial infections that may lead to lesions of keratinized tissues, like skin, hair and nails. A total of 6068 individuals from Goiânia, GO, with suspected dermatophytic lesions were examined over a period of five years (1993-1997) in order to determine the incidence and etiology of dermatophytosis. Material collected from different body parts was submitted to direct microscopic examination using KOH, cultured in Sabouraud agar and microscopically examined for colony morphology, with the identification of 1595 dermatophytes. Trichophyton rubrum (37.4%), T. mentagrophytes (36.4%) and Microsporum canis (16%) were the species most frequently isolated. Dermatophytes were more frequently found producing lesions in the feet (30.5%), inguinal and crural regions (17.8%) and glabrous body regions (15.5%). The distribution of the different infected body sites was determined in terms of the respective etiologic agents found. Better hygiene conditions and an early diagnosis are the most important tools to control and reduce the incidence of dermatophytosis in Goiânia, GO.

Functional morphology of the locomotor system in the northern smooth-tailed tree shrew (Dendrogale murina)

The locomotor system of the northern smooth-tailed tree shrew (Dendrogale murina), one of the arboreal species of Scandentia, was examined by means of macroscopic anatomy. In this study, we describe the muscular system in the shoulder, forearm, hip and crural regions. The M. deltoideus and the acromion of the scapula were well-developed. The characteristic postscapular fossa was distinguishable in the scapula. The M. teres major and M. triceps brachii possessed large bundles and were attached to the postscapular fossa. In the hindlimb region, the M. biceps femoris was inserted into large area of distal hindlimb. The M. tenuissimus was discernible beneath the M. biceps femoris. We suggest that these findings may contribute to our understanding of arboreal locomotion in this species, and that this may typically represent the arboreal adaptational pattern of the muscular system in the Scandentia.

Role of the cerebellum and motor cortex in the regulation of visually controlled locomotion

An account is given of the current state of knowledge of the contributions of the cerebellum and the forelimb motor cortex (MC) to the neural control of walking movements in the cat. The main emphasis is on information obtained by recording from single MC and cerebellar neurones in chronically instrumented cats engaged in walking on the rungs of a horizontal ladder, a form of locomotion that is heavily dependent on visual input and for which the integrity of MC is essential. Evidence from the authors' laboratory and from other studies is presented which establishes that MC neurones, including pyramidal tract neurones, show higher levels of activity during ladder walking than during overground walking (i.e., when less constraint exists over the locus of footfall) and that this increase is greatest in late swing-early stance in the contralateral forelimb, consistent with one role of MC being to help determine the locus of footfall. However, many MC neurones develop peak activity at other times in the step cycle, and a comparison with recordings during treadmill walking suggests MC may also help regulate stance duration when walking speed is an important performance variable. Recordings from Purkinje cells and cerebellar nuclear neurones show that during ladder walking step-related activity is widespread in the vermal, paravermal, and crural regions of cortex and in the interposed and dentate nuclei. Nuclear cell activity is so timed that it could be contributing to producing the locomotor rhythms evident in MC cells, although this is not yet proven. Results are also presented and discussed relating to MC and cerebellar neuronal responses that occur when a step onto an unstable rung results in an unexpected external perturbation of the forelimb step cycle. MC responses begin with onset latency as short as 20 ms so that MC may assist spinal reflex mechanisms to produce a post hoc compensatory change in motor output. However, work in progress suggests that corresponding responses in paravermal cerebellum are weak and infrequent, so provisionally it seems that the MC responses are initiated via pathways that do not pass through the cerebellum. By contrast, current work involving a paradigm in which a ladder rung is motor driven to a new position as the animal approaches (thereby providing a visual cue that an adaptive change in gait will soon be required) is revealing in lateral cerebellar neurones, including dentate neurones, changes in discharge that are time locked to the execution of an adapted pace. In addition, there are prominent earlier responses, which begin at short latency after the onset of rung movement. These apparently visual responses have characteristics that encourage the speculation that they may represent a cerebellar signal that "primes for action" other more directly motor regions of the central nervous system.

Diaphragm thickness heterogeneity at functional residual capacity and total lung capacity.

One of the determinants of muscular force is the number of myofibrils in parallel, which is approximated by thickness. To better understand the heterogeneity of diaphragm thickness, we quantified the interregional and radial patterns of thickness of nine canine diaphragms rapidly perfusion fixed in situ with glutaraldehyde at functional residual capacity (FRC) (n = 6) and total lung capacity (TLC) (n = 3). Thickness was determined gravimetrically from punch biopsies radiating from the central tendon to rib cage insertion in ventral, middle, and dorsal costal and crural regions. For comparison, the contralateral unfixed hemidiaphragm was sampled in the same fashion. The findings of this investigation include the following. 1) The costal diaphragm exhibits the same pattern of interregional heterogeneity at FRC, TLC, and in the freshly excised state. 2) The costal diaphragm is significantly thinner at FRC in situ (0.17 +/- 0.01 cm) than is the freshly excised contralateral diaphragm (0.21 +/- 0.01 cm; P < 0.05), whereas there is no significant difference between thickness at TLC and the freshly excised state. 3) There is significant, previously underscribed, radial tapering from the rib cage attachment (0.24 +/- 0.02) to the central tendon insertion (0.15 +/- 0.01 cm; P < 0.05) that is exaggerated at TLC. 4) With passive inflation from FRC to TLC, the greatest increase in thickness occurs close to the rib cage attachment for the ventral and medial costal regions but close to the central tendon in the dorsal and crural regions. We conclude that the diaphragm at FRC and TLC exhibits radial thickness heterogeneity that cannot be predicted from dimensions of the freshly excised diaphragm.(ABSTRACT TRUNCATED AT 250 WORDS)

上部消化管運動機能の障害 おう吐と横隔膜

Vomiting is a complex reflex that is centrally programmed and involves a sequential and coordinated contraction of many different muscles, such as the gastrointestinal smooth muscle, the upper airway muscles, and the muscles involved in respiration. The respiratory muscles are important contributors to vomiting. The abdominal muscles, parasternal intercostal muscles, and costal part of the diaphragm contract phasically during vomiting to increase abdominal pressure and aid expulsion. Compared with breathing at rest, the relative phase of the diaphragm and abdominal muscles changes so that during vomiting both the inspiratory and expiratory respiratory muscles contract together to assist expulsion. During CO2 rebreathing, electrical activity and shortening increase in the costal, medial crural, central crural, and lateral crural regions of the diaphragm, compared to breathing at rest. However, during vomiting, (1) both shortening and EMG activity significantly increase compared to the resting state in the costal segment; (2) lateral crural shortening does not increase in spite of a significant increase in EMG activity; (3) the medial crural lengthens without any increase in EMG activity; and (4) the central crural diaphragm shows a significant biphasic length change, with initial shortening followed by lenghthening. A strong coordinated interaction between the brain stem centers responsible for the control of respiration and of vomiting is suggested.

Diaphragm injury and myofibrillar structure induced by resistive loading

The purpose of this study was to determine whether ventilatory failure is associated with muscle fiber damage and myofibrillar protein alterations. Ventilatory failure was induced by tightening a polyvinyl band around the trachea of hamsters (TB; n = 14) for 6 days, which resulted in severe respiratory acidosis (PCO2: 97.9 +/- 29.6 vs. 51.6 +/- 19.6 Torr; pH: 7.16 vs. 7.35), hypoxemia (PO2: 42.8 +/- 16.8 vs. 65.9 +/- 25.8 Torr), and increased pulmonary resistance (1.89 +/- 1.61 vs. 0.29 +/- 0.27 cmH2O.ml-1 x min; P < 0.05). The point-counting technique of hematoxylin- and eosin-stained cross sections showed a higher area fraction of abnormal muscle and inflammatory cells in the costal [0.133 +/- (SE) 0.33 vs. 0.040 +/- 0.010] and crural regions (0.069 +/- 0.020 vs. 0.012 +/- 0.003) of the diaphragm in TB hamsters than in control hamsters. Electron micrographs revealed sarcomeric disruption and Z band streaming in the diaphragm of TB hamsters. Myofibrillar changes of the diaphragm associated with ventilatory failure were quantitative (i.e., a lower yield of purified myofibrils) but not qualitative (similar sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles); however, sulfhydryl group reactivities were reduced (P < 0.05). Proteolysis of purified myofibrils from the diaphragm digested with calpain showed faster degradation rates for tropomyosin and alpha-actinin but not for all proteins for the TB animals. Ventilatory failure induced by resistive loading was associated with diaphragm injury; some of this injury was linked to changes in myofibrillar complexes, specifically their susceptibility to calpain-mediated degradation.

Circadian rhythm of glycogen in the hamster diaphragm.

The purpose of this study was to determine the diurnal fluctuation of glycogen stores for the whole hemidiaphragm and within a specific myofibrillar ATPase (M-ATPase) fibre type and diaphragmatic region. Fifty-six golden Syrian hamsters were randomly divided into six groups according to the time of sampling biopsies from the diaphragm: 03:00, 07:00, 11:00, 15:00, 19:00, and 23:00. The right hemidiaphragm was quick frozen and biochemically assayed for glycogen levels. Biopsies from the left hemidiaphragm of the same animal were cut from the anterior costal and crural regions, and stained with periodic acid--Schiff (PAS) and for M-ATPase. Optical density measures of PAS-stained fibres were determined to quantitate glycogen in different M-ATPase fibre types and diaphragmatic regions. Biochemical assay of the entire hemidiaphragm showed slightly greater glycogen content of biopsies taken at 11:00 and 15:00 than at 03:00, 19:00, and 23:00 (range of differences: 6.4-10.0%). However, glycogen levels within a specific M-ATPase fibre type and diaphragm region were not different in biopsies sampled at different times. Because the hamster has a small diurnal variation of glycogen in the diaphragm, which is similar to the small diurnal variation of glycogen in human skeletal muscle, this species may be a good animal model for metabolic studies of the diaphragm that could be affected by diurnal glycogen variability.

Thoracic epidural anesthesia increases diaphragmatic shortening after thoracotomy in the awake lamb.

Prolonged inhibition of diaphragmatic function occurs after thoracic and upper abdominal surgery. It was hypothesized that thoracic epidural anesthesia on the day after a thoracotomy could block inhibitory neural pathways and increase the shortening of costal and crural diaphragmatic segments. Pairs of sonomicrometer crystals were implanted into the costal and crural regions of the diaphragm through a right lateral thoracotomy in 14 30-kg, 4-5-month-old lambs. One day after surgery, a thoracic epidural catheter was placed at the T8-T9 level. Regional diaphragmatic shortening normalized to end-expiratory length (%LFRC), was measured by sonomicrometry in these awake lambs. Changes in gastric (delta Pgas), esophageal (delta Pes), and transdiaphragmatic (delta Pdi) pressures were measured with transnasal balloon catheters. End-tidal carbon dioxide (FETCO2), costal and crural electromyogram (Edi), and tidal volume (VT) were measured. Inductance plethysmography was used in four lambs to assess relative contributions of the rib cage and abdomen to VT. Control values were obtained during quiet breathing and while rebreathing at up to 10% FETCO2. To block thoracic dermatomes, 1% or 2% lidocaine was injected through the epidural catheter. Measurements were repeated after each lidocaine injection. There was no change of resting length with 1% lidocaine; costal resting length increased by 22% with 2% lidocaine. After 2% lidocaine, costal %LFRC increased from control both during quiet breathing (8.7 +/- 0.7 to 18.1 +/- 1, mean +/- SEM%) and at FETCO2 10% (22.1 +/- 2 to 33.7 +/- 3%). VT during quiet breathing was unchanged after 1% lidocaine but increased from 235 +/- 16 to 283 +/- 28 ml after 2% lidocaine. At 10% FETCO2, delta Pdi was unchanged after 1% lidocaine and decreased from 36.5 +/- 4.3 to 26.3 +/- 4.9 cmH2O after 2% lidocaine. Regional delta Edi was unchanged with both 1% and 2% lidocaine at rest and during carbon dioxide rebreathing. Plethysmography in three lambs showed a reduction in rib cage contribution to tidal volume with 2% lidocaine during quiet breathing. Improved postoperative tidal volume and diaphragmatic shortening after thoracic epidural blockade may be due to changes of chest wall conformation and resting length and a shift of the workload of breathing from the rib cage to the diaphragm caused by intercostal muscle paralysis.

Differential function of the costal and crural diaphragm during emesis in canines

In six mongrel dogs under thiopental anesthesia, piezoelectric transducers and bipolar electromyographic (EMG) wires were installed onto left costal, medial crural and lateral crural segments of the diaphragm. During CO 2 rebreathing, shortening and EMG activity increased significantly in all three regions of the diaphragm compared to resting breathing. During emesis, (1) both shortening and EMG activity significantly increased compared to resting in costal segment; however, (2) lateral crural shortening was not increased in spite of significant increase in EMG activity; furthermore, (3) the medial crural segment lengthened without any increased EMG activity. These results demonstrate a differential recruitment of costal and crural diaphragm segments, and an additional differential activity within the crural segment between medial and lateral crural regions, during emesis. This activity of the canine diaphragm is consistent with a central influence of emesis upon individual regions of the diaphragm.

Myosin heavy chain composition in the rat diaphragm: effect of age and exercise training.

Increases in aerobic capacity in both young and senescent rats consequent to endurance exercise training are now known to occur not only in locomotor skeletal muscle but also in diaphragm. In the current study the effects of aging and exercise training on the myosin heavy chain (MHC) composition were determined in both the costal and crural diaphragm regions of female Fischer 344 rats. Exercise training [treadmill running at 75% maximal oxygen consumption (1 h/day, 5 day/wk, x 10 wk)] resulted in similar increases in plantaris muscle citrate synthase activity in both young (5 mo) and old (23 mo) trained animals (P < 0.05). Computerized densitometric image analysis of fast and slow MHC bands revealed the ratio of fast to slow MHC to be significantly higher (P < 0.005) in the crural compared with costal diaphragm region in both age groups. In addition, a significant age-related increase (P < 0.05) in percentage of slow MHC was observed in both diaphragm regions. However, exercise training failed to change the relative proportion of slow MHC in either the costal or crural region.