Control of Motility in the Internal Anal Sphincter

The internal anal sphincter (IAS) plays an important role in the maintenance of fecal continence since it generates tone and is responsible for > 70% of resting anal pressure. During normal defecation the IAS relaxes. Historically, tone generation in gastrointestinal muscles was attributed to mechanisms arising directly from smooth muscle cells, ie, myogenic activity. However, slow waves are now known to play a fundamental role in regulating gastrointestinal motility and these electrical events are generated by the interstitial cells of Cajal. Recently, interstitial cells of Cajal, as well as slow waves, have also been identified in the IAS making them viable candidates for tone generation. In this review we discuss four different mechanisms that likely contribute to tone generation in the IAS. Three of these involve membrane potential, L-type Ca²⁺ channels and electromechanical coupling (ie, summation of asynchronous phasic activity, partial tetanus, and window current), whereas the fourth involves the regulation of myofilament Ca²⁺ sensitivity. Contractile activity in the IAS is also modulated by sympathetic motor neurons that significantly increase tone and anal pressure, as well as inhibitory motor neurons (particularly nitrergic and vasoactive intestinal peptidergic) that abolish contraction and assist with normal defecation. Alterations in IAS motility are associated with disorders such as fecal incontinence and anal fissures that significantly decrease the quality of life. Understanding in greater detail how tone is regulated in the IAS is important for developing more effective treatment strategies for these debilitating defecation disorders.

Biochemical and Utralmicroscopic Evaluation of Myofibril Proteins and Collagen during Ageing in Broiler Chicken PSE (Pale, Sof, Exudative) Meat

Abstract The aim of this work was to study the myofibril proteins and collagen fraction changes in broiler chickens PSE (pale, soft, exudative) meat during ageing and their relationship to meat quality. The results presented an increase of myofibril proteins and collagen solubility promoted by the enhanced proteases activities during storage. Ultramicroscopically, the PSE meat samples revealed intracellularly a sarcomere super contraction and lacunas within the A and I bands while Z-lines appeared very dense and fragmented in comparison to normal samples. This observation was noticed already at 4h storage while extracellularly collagen fibrils decreased visually within the endomysium only after 24h of conditioning. These results influenced the quality as the PSE meat presented better functional properties at the first hours of conditioning before further proteins degradation by proteases. Thereafter, at the later ageing stage a further disintegration of the abnormal meat structure would affect the meat functional properties.

Acetaminophen mitigates myocardial injury induced by lower extremity ischemia-reperfusion in rat model

Abstract Objective: The injury-reducing effect of acetaminophen, an effective analgesic and antipyretic on ischemia-reperfusion continues to attract great attention. This study analyzed the protective effect of acetaminophen on myocardial injury induced by ischemia-reperfusion in an experimental animal model from lower extremity ischemia-reperfusion. Methods: Twenty-four Sprague-Dawley female rats were randomized into three groups (n=8) as (i) control group (only laparotomy), (ii) aortic ischemia-reperfusion group (60 min of ischemia and 120 min of reperfusion) and (iii) ischemia-reperfusion + acetaminophen group (15 mg/kg/h intravenous acetaminophen infusion starting 15 minutes before the end of the ischemic period and lasting till the end of the reperfusion period). Sternotomy was performed in all groups at the end of the reperfusion period and the heart was removed for histopathological examination. The removed hearts were histopathologically investigated for myocytolysis, polymorphonuclear leukocyte (PMNL) infiltration, myofibrillar edema and focal hemorrhage. Results: The results of histopathological examination showed that acetaminophen was detected to particularly diminish focal hemorrhage and myofibrillar edema in the ischemia-reperfusion + acetaminophen group (P<0.001, P=0.011), while there were no effects on myocytolysis and PMNL infiltration between the groups (P=1.000, P=0.124). Conclusion: Acetaminophen is considered to have cardioprotective effect in rats, by reducing myocardial injury induced by abdominal aortic ischemia-reperfusion.

A case of generalized argyria presenting with muscle weakness

BACKGROUND: Argyria is a rare irreversible cutaneous pigmentation disorder caused by prolonged exposure to silver. Herein, we report a case of generalized argyria that developed after chronic ingestion of soluble silver-nano particles and presented with muscle weakness. CASE PRESENTATION: A 74-year-old woman visited our emergency room, complaining of fever and mental deterioration. She was diagnosed with acute pyelonephritis and recovered after antibiotic therapy. At presentation, diffuse slate gray-bluish pigmented patches were noticed on her face and nails. Two months prior to visiting our hospital, she was diagnosed with inflammatory myopathy and given steroid therapy at another hospital. We performed a nerve conduction study that revealed polyneuropathy. In skin biopsies from pigmented areas of the forehead and nose, the histopathologic results showed brown-black granules in basement membranes of sweat gland epithelia, which are diagnostic findings of argyria. We reviewed pathology slides obtained from the left thigh muscles and found markedly degenerated myofibers with disorganization of myofibrils without inflammatory reactions, consistent with unspecified myopathy, rather than inflammatory myopathy. The patient was diagnosed with generalized argyria with polyneuropathy and myopathy and transferred to a rehabilitation institution after being tapered off of steroids. CONCLUSIONS: Clinicians should be aware of clinical manifestations of argyria and consider it in differential diagnosis when they examine patients who present with skin pigmentation and muscle weakness.

Calcium Sensitization Mechanisms in Gastrointestinal Smooth Muscles

An increase in intracellular Ca2+ is the primary trigger of contraction of gastrointestinal (GI) smooth muscles. However, increasing the Ca2+ sensitivity of the myofilaments by elevating myosin light chain phosphorylation also plays an essential role. Inhibiting myosin light chain phosphatase activity with protein kinase C-potentiated phosphatase inhibitor protein-17 kDa (CPI-17) and myosin phosphatase targeting subunit 1 (MYPT1) phosphorylation is considered to be the primary mechanism underlying myofilament Ca2+ sensitization. The relative importance of Ca2+ sensitization mechanisms to the diverse patterns of GI motility is likely related to the varied functional roles of GI smooth muscles. Increases in CPI-17 and MYPT1 phosphorylation in response to agonist stimulation regulate myosin light chain phosphatase activity in phasic, tonic, and sphincteric GI smooth muscles. Recent evidence suggests that MYPT1 phosphorylation may also contribute to force generation by reorganization of the actin cytoskeleton. The mechanisms responsible for maintaining constitutive CPI-17 and MYPT1 phosphorylation in GI smooth muscles are still largely unknown. The characteristics of the cell-types comprising the neuroeffector junction lead to fundamental differences between the effects of exogenous agonists and endogenous neurotransmitters on Ca2+ sensitization mechanisms. The contribution of various cell-types within the tunica muscularis to the motor responses of GI organs to neurotransmission must be considered when determining the mechanisms by which Ca2+ sensitization pathways are activated. The signaling pathways regulating Ca2+ sensitization may provide novel therapeutic strategies for controlling GI motility. This article will provide an overview of the current understanding of the biochemical basis for the regulation of Ca2+ sensitization, while also discussing the functional importance to different smooth muscles of the GI tract.

Cap Myopathy With a Heterozygous TPM3 Missense Mutation

Cap myopathy is pathologically characterized by cap structures comprising well-demarcated areas under the sarcolemma and containing deranged myofibrils and scattered Z-disks. Clinically it presents with slowly progressive muscle weakness, myopathic face, and frequent respiratory insufficiency. Four genes have been reported to be associated with the disease: TPM2, TPM3, ACTA1, and NEB. Here we describe that a patient presenting with mild limb weakness with facial affection showed cap structures on muscle pathology and carried a heterozygous TPM3 mutation.

S100 and p65 expression are increased in the masseter muscle after botulinum toxin-A injection / 대한악안면성형재건외과학회지

BACKGROUND: The purpose of this study was to compare the expression levels of p65 and S100 in the rat masseter muscle after the injection of different concentrations of botulinum toxin-A (BTX-A). METHODS: We injected either 5 or 10 U of BTX-A into both masseter muscle of rats. As a control group, the same volume of saline was injected. After 14 days, the animals were sacrificed. Subsequently, a biopsy and immunohistochemical staining of the samples were performed using a p65 or S100 antibody. RESULTS: The cross-sectional area of each myofibril was significantly reduced by BTX-A injection (P < 0.001). The expression of p65 and S100 increased significantly with increasing concentrations of BTX-A (P < 0.001). CONCLUSIONS: The injection of BTX-A into the masseter muscle induced muscle atrophy. Subsequently, p65 and S100 expression in myoblasts were increased for the protection of muscle cells.

Base of the skull morphology and Class III malocclusion in patients with unilateral cleft lip and palate

OBJECTIVE: The aim of the present study was to determine the morphological differences in the base of the skull of individuals with cleft lip and palate and Class III malocclusion in comparison to control groups with Class I and Class III malocclusion. METHODS: A total of 89 individuals (males and females) aged between 5 and 27 years old (Class I, n = 32; Class III, n = 29; and Class III individuals with unilateral cleft lip and palate, n = 28) attending PUC-MG Dental Center and Cleft Lip/Palate Care Center of Baleia Hospital and PUC-MG (CENTRARE) were selected. Linear and angular measurements of the base of the skull, maxilla and mandible were performed and assessed by a single calibrated examiner by means of cephalometric radiographs. Statistical analysis involved ANCOVA and Bonferroni correction. RESULTS: No significant differences with regard to the base of the skull were found between the control group (Class I) and individuals with cleft lip and palate (P > 0.017). The cleft lip/palate group differed from the Class III group only with regard to CI.Sp.Ba (P = 0.015). Individuals with cleft lip and palate had a significantly shorter maxillary length (Co-A) in comparison to the control group (P < 0.001). No significant differences were found in the mandible (Co-Gn) of the control group and individuals with cleft lip and palate (P = 1.000). CONCLUSION: The present findings suggest that there are no significant differences in the base of the skull of individuals Class I or Class III and individuals with cleft lip and palate and Class III malocclusion. .

OBJETIVO: o objetivo do presente estudo foi determinar diferenças morfológicas da base do crânio de indivíduos portadores de fissura de lábio e palato e de má oclusão de Classe III, comparado-os com indivíduos controle com má oclusão de Classes I ou III. MÉTODOS: oitenta e nove indivíduos, de ambos os sexos, com idade variando entre 5 e 27 anos, Classe I (n = 32), Classe III não fissurados (n = 29) e Classe III com fissura labiopalatina unilateral (n = 28), oriundos do Centro de Odontologia e Pesquisa da PUC-MG e do Centro de Atendimento de Fissurados do Hospital da Baleia e da PUC-MG (CENTRARE), foram selecionados. Medições lineares e angulares da base do crânio, maxila e mandíbula foram realizadas e avaliadas por um único examinador calibrado, por meio de radiografias cefalométricas. Foram utilizados os testes ANCOVA e correção de Bonferroni para a análise estatística dos dados. RESULTADOS: com relação à base do crânio, os resultados não indicaram diferença estatística entre indivíduos controle (Classe I) e os indivíduos com fissuras (p > 0,017). O grupo com fissura foi diferente do grupo Classe III somente em relação à medida CI.Sp.Ba (p = 0,015). O comprimento maxilar (Co-A) apresentou diferença estatisticamente significativa na comparação entre o grupo controle (Classe I) e o grupo com fissuras (p < 0,001), sendo que os fissurados apresentaram uma maxila menor. Não foram encontradas diferenças na mandíbula (Co-Gn) entre indivíduos do grupo controle (Classe I) e indivíduos fissurados (p = 1,000). CONCLUSÃO: os resultados sugerem que não houve diferença estatisticamente significativa na base do crânio entre indivíduos Classe I e III e indivíduos com fissuras de lábio e palato com má oclusão de Classe III. .

Aging of Skeletal Muscle Fibers

Aging has become an important topic for scientific research because life expectancy and the number of men and women in older age groups have increased dramatically in the last century. This is true in most countries of the world including the Republic of Korea and the United States. From a rehabilitation perspective, the most important associated issue is a progressive decline in functional capacity and independence. Sarcopenia is partly responsible for this decline. Many changes underlying the loss of muscle mass and force-generating capacity of skeletal muscle can be understood at the cellular and molecular levels. Muscle size and architecture are both altered with advanced adult age. Further, changes in myofibers include impairments in several physiological domains including muscle fiber activation, excitation-contraction coupling, actin-myosin cross-bridge interaction, energy production, and repair and regeneration. A thorough understanding of these alterations can lead to the design of improved preventative and rehabilitative interventions, such as personalized exercise training programs.

Analysis of Disease Progression-Associated Gene Expression Profile in Fibrillin-1 Mutant Mice: New Insight into Molecular Pathogenesis of Marfan Syndrome

Marfan syndrome (MFS) is a dominantly inherited connective tissue disorder caused by mutations in the gene encoding fibrillin-1 (FBN1) and is characterized by aortic dilatation and dissection, which is the primary cause of death in untreated MFS patients. However, disease progression-associated changes in gene expression in the aortic lesions of MFS patients remained unknown. Using a mouse model of MFS, FBN1 hypomorphic mouse (mgR/mgR), we characterized the aortic gene expression profiles during the progression of the MFS. Homozygous mgR mice exhibited MFS-like phenotypic features, such as fragmentation of elastic fibers throughout the vessel wall and were graded into mgR1-4 based on the pathological severity in aortic walls. Comparative gene expression profiling of WT and four mgR mice using microarrays revealed that the changes in the transcriptome were a direct reflection of the severity of aortic pathological features. Gene ontology analysis showed that genes related to oxidation/reduction, myofibril assembly, cytoskeleton organization, and cell adhesion were differentially expressed in the mgR mice. Further analysis of differentially expressed genes identified several candidate genes whose known roles were suggestive of their involvement in the progressive destruction of aorta during MFS. This study is the first genome-wide analysis of the aortic gene expression profiles associated with the progression of MFS. Our findings provide valuable information regarding the molecular pathogenesis during MFS progression and contribute to the development of new biomarkers as well as improved therapeutic strategies.

A Review of Electrocardiography Changes and Clinical Manifestations in Scrub Typhus in a Single Center / 대한내과학회지

The mechanism of electrocardiography (ECG) changes in patients with scrub typhus is still not clear. Orientia tsutsugamushi causes vasculitis in scrub typhus patients, which result in non-specific damage to the heart. However, serious damage to myofibril of the heart is not accompanied. Thus, chronic cardiac sequelae are rare. In addition to myocarditis, a variety of cardiac complications such as myocardial infarction, pericarditis have been reported. Additional research is needed to clarify the main mechanisms that cause changes in the ECG in scrub typhus whether it comes from electrolyte imbalance, fever or cardiac injury such as myocarditis.

TNNI3K is a novel mediator of myofilament function and phosphorylates cardiac troponin I

The phosphorylation of cardiac troponin I (cTnI) plays an important role in the contractile dysfunction associated with heart failure. Human cardiac troponin I-interacting kinase (TNNI3K) is a novel cardiac-specific functional kinase that can bind to cTnI in a yeast two-hybrid screen. The purpose of this study was to investigate whether TNNI3K can phosphorylate cTnI at specific sites and to examine whether the phosphorylation of cTnI caused by TNNI3K can regulate cardiac myofilament contractile function. Co-immunoprecipitation was performed to confirm that TNNI3K could interact with cTnI. Kinase assays further indicated that TNNI3K did not phosphorylate cTnI at Ser23/24 and Ser44, but directly phosphorylated Ser43 and Thr143 in vitro. The results obtained for adult rat cardiomyocytes also indicated that enhanced phosphorylation of cTnI at Ser43 and Thr143 correlated with rTNNI3K (rat TNNI3K) overexpression, and phosphorylation was reduced when rTNNI3K was knocked down. To determine the contractile function modulated by TNNI3K-mediated phosphorylation of cTnI, cardiomyocyte contraction was studied in adult rat ventricular myocytes. The contraction of cardiomyocytes increased with rTNNI3K overexpression and decreased with rTNNI3K knockdown. We conclude that TNNI3K may be a novel mediator of cTnI phosphorylation and contribute to the regulation of cardiac myofilament contraction function.

Impact of spiral orientation of myofibres and ventricular syncitium: study of left ventricular dysfunction in 22 patients of copd with cor-pulmonale with normal coronary arteries.

Clinical presentation of breathlessness on exertion is often confused between angina equivalent - breathlessness and pulmonary origin breathlessness. echocardiographyand Dop-pler evaluation has been used for differentiating these aetiologies in an individual. However, at times even echocardiography is not informative as it brings out biventricular dysfunction and hence LV dysfunction can not be ruled out in COPD, cor-pulmonale patients on clinical grounds alone. Established cases of COPD, cor-pulmonale may have. significant LV dysfunction also. The possible explanation of this biventricular dysfunction is anatomical. These patients have LVD without IHD. EGG evidence and angiographic evidence of IHD is lacking though LV dysfunction is present. The observational study tries to evaluate left ventricular function in COPD, cor-pulmonale patients

The influence of denervation on myofiber morphology of the adductor and abductor in patients with recurrent laryngeal nerve paralysis / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To investigate the influence of denervation on myofiber morphology of the adductor and the abductor in patients with recurrent laryngeal nerve (RLN) paralysis and to provide experimental evidence for the clinical feasibility of RLN repair.@*METHOD@#Adductor muscles were acquired from the lateral cricoarytenoid muscle (LCAM) and abductor muscles from the posterior cricoarytenoid muscle(PCAM). Normal human PCAM and LCAM are treated as control group (n = 7). Thirty-eight cases of PCAM with damaged RLN were divided into five groups according to the duration of their RLN damage: 0.5-1 year (7 cases), > 1-2 years (10 cases), > 2-3 years (8 cases), > 3-6 years (8 cases) and > 6 years (5 cases); twenty-nine cases of LCAM were also divided into five groups: 0.5-1 year (7 cases), > 1-2 years (6 cases); > 2-3 years (6 cases), > 3-6 years (6 cases) and > 6 years group(4 cases). They were all stained with HE and Masson three-color staining, the fiber cross-sectional area of muscle tissue and collagen connective tissue were quantitative analyzed. The changes of myofiber morphology of adductor and abductor muscles after the loss of the RLN were analyzed with image analysis system.@*RESULT@#The transverse areas of myofibers gradually decreased and those of collagen fibers gradually increased with the prolongation of denervation. (1) Difference between the denervated groups of LCAM of 0.5-1 year, > 1-2 years and > 2-3 years groups were not significant (P > 0.05). Fiber cross-sectional area of > 3-6 years group decreased most obviously with significantly difference compared with > 2-3 years group (P 1-2 years group, > 2-3 years group and > 3-6 years of PCAM(P 3-6 years and > 6 years of two kinds of laryngeal intrinsic muscle (P > 0.05); (4) Fiber cross-sectional area of each group of the LCAM after 1 year denervation were significantly greater than that of the PCAM under same conditions (P < 0.05).@*CONCLUSION@#The influence of denervation on myofiber morphology following denervation is different between the abductor and adductor owing to the different fiber type composition and functional properties. The rate of muscle atrophy of the adductor is slower than that of the abductor. To restore the structure and function of denervated laryngeal muscles better, the recurrent laryngeal nerve injury repair surgery for PCA muscle function recovery should be carried out within 1 year after denervation while the surgery for LCA muscle function recovery should be carried out within 3 years after denervation.

Mechanism of incorporation of newly synthesized myosin alkali light chain into myofibril

The present work was designed to study the incorporation of newly synthesized myosin alkali light chain [MLC] molecules into myofibris. cDNA of fast skeletal muscle type of MLC tagged with green fluorescence protein [LC3f-GFP] was transfected into cultured chicken cardiomyocytes, and the assembly of expressed LC3f-GFP was observed in living cells under a fluorescence microscope equipped with a cooled CCD camera. At 14-16 hours after transfection, LC3f-GFP was diffusely distributed in the cytoplasm of cardiomyocytes. In some cells, however, intense fluorescence spots of LC3f-GFP were found along myofibrils with a periodically of 1.2 micro m. Confocal microscopy of such cells, stained with rhodamine-labeled phalloidin, revealed the fluorescence spots of LC3f-GFP localized at both ends of A-bond. When these cells were further incubated, LC3f-GFP came to be localized at all levels of the A-bands by 26 hours after transfection. These results indicate that myosin filaments are not replaced with newly synthesized myosin molecules at once along their length, but molecules in filaments are replaced individually from their ends

Mechanisms of Muscle Wasting in Patients with Sepsis / 대한구급학회지

Muscle wasting is commonly seen in patients with sepsis as a consequence of the catabolic response in skeletal muscle. Muscle wasting can occur in cases that have an imbalance between degradation and synthesis of muscle proteins. Although decrements in the synthesis of muscle proteins may contribute to sepsis-induced muscle wasting, it has been recognized that increments in its degradation play a more essential role in muscle wasting. Muscle wasting in sepsis patients has some significant clinical consequences such as reduced ambulation and exercise tolerance, and an increased risk for pulmonary and thromboembolic complications. Several mechanisms have been proposed for sepsis-induced muscle wasting. Increased proteolysis via the ubiquitin-proteasome pathway and the calpains system is one of the principal mechanisms of muscle wasting induced by sepsis. Calpains are activated by calcium, which increases in patients with sepsis. The activation of the calpains system disrupts the sarcomere of the myofibrils, resulting in the release of myofilaments that are subsequently ubiquitinated and degraded by the 26S proteasome complex. Recent studies have suggested that transcriptional factors such as NF-kappaB and FoxO, and the apoptosis and autophagy-lysosome pathways may also be involved in sepsis-induced muscle wasting. This review briefly summarizes the contribution of these mechanisms of muscle wasting in patients with sepsis and the possible therapeutic agents to treat it.

Myofibrillar myopathy with limb-girdle phenotype in a Thai patient.

Myofibrillar myopathy (MFM) encompasses a genetically and clinically heterogeneous group of inherited or sporadic skeletal muscle disorders characterized pathologically by the presence of myofibrillar dissolution associated with accumulation of myofibrillar degradation products and ectopic expression of multiple proteins especially Z-disk related proteins. Patients with MFM initially present with muscle weakness and commonly developed cardiomypathy in the advanced stage. To date, mutations of genes encoding Z-disk proteins or proteins maintaining myofibrillar integrity including ZASP, MYOT, DES, FLNC and CRYAB underlie MFM. The authors herein report a 29-year-old Thai woman with a clinical diagnosis of autosomal dominant limb-girdle muscular dystrophy (LGMD1) who has one affected grandmother. The patient was subsequently found to have MFM based on her myopathological findings. Analyses of all MFM-genes known to date revealed no mutations. The current case emphasizes the importance of muscle biopsy in LGMD1 patients and a wide range of phenotypic variations among patients with MFM. The causative genes underlying the majority of MFM remain uncovered. Close monitoring of the cardiac function is crucial to prevent mortality among these patients.

The Effects of Sciatic Neurectomy on Rat Gastrocnemius Muscle / 체질인류학회지

The effects of unilateral sciatic neurectomy on gastrocnemius muscle were studied in adult male rats. The morphological changes of both gastrocnemius muscles were observed by light and electron microscopy. Western blot analysis was performed to study the protein expression. Following the denervation, the affected muscle weights decreased significantly than normal. And the denervation led to a significant reduction in the area and diameter of muscle fibers on light microscopy. The affected muscle fibers showed the decreasing in size and the irregularity of myofibrilar arrangement on electron microscopy. On transverse view, the area of affected muscle fibers were smaller than normal. Their myofibrils were smaller and very irregular in size. The thin and thick myofilaments were not regular and partially lost. Mitochondria between myofibrils and subsarcolemmal area in affected muscle fibers were damaged and partially lost. The sacoplasmic reticulum and T-tubules were mostly lost and irregular. Some satellite cells were observed adjacent the muscle fiber, but they were inactive morphologically. On longitudinal view, most of myofibrils in affected muscle fibers were lost generally or partially although the their most sarcomeres were regularly arranged. Z line and myofilaments were lost partially and were partially irregularly arranged. The loss of thin myofilaments was more than that of thick myofilaments. Much debris of cell organelles were scattered among myofibrils. The expression of MyoD and myogenin were decrease significantly and the expression of p-mTOR and p-FOXO1 were decreased, too. On the other hand, MuRF1 was increased significantly. Taken together, the main effect of gastrocnemius muscle by sciatic neurectomy is the atrophy as a result of the loss of myofilaments and cell organelles through the decrease of protein synthesis and the increase of protein degradation.

Ultrastructural Characteristics of the Orbicularis Oris Muscle in the Microform Cleft Lip

RecentIy, increasing emphasis has been placed on the histochemical and ultrastructural characteristics of the muscle in the cleft lip. Schendelet al and Cho et al demonstrated a non-neurogenic muscle atrophy and mitochondrial myopathy, and Raposio examined an increased inflammatory reaction, but no mitochondrial abnormalities of the cleft lip muscle. However, no study has focused on the ultrastructure of the microform cleft lip muscle. Eleven muscle specimens were obtained from the microform cleft lip patients at the time of primary repair from Jun.1997 to Aug.1998 and they were submitted to histologic and histochemical examinations as well as electron microscopy. A non-neurogenic muscle atrophy was seen on HE stain. Modified Gomori trichrome stain revealed red granularity of the muscle fibers, suggesting an increase in mitochondrial activity, however, no ragged-red fibers, a typical sign of mitochondrial myopathy, was found. Electron microscopy revealed atrophy, disarray, and focal loss of myofibrils, dilated sarcoplasmic reticulum with glycogen deposit, and interstitial fibrosis. However, the mitochondrial morphology was well preserved with an increase of the number of the mitochondria which might be secondary change to muscle degeneration. In conclusion, ultrastructural characteristics of the orbicularis oris muscle in the microform cleft lip is non-neurogenic muscle atrophy without mitochondrial myopathy which is controversial in the complete cleft lip.

Correlation between biochemical properties and adaptive diversity of skeletal muscle myofibrils and myosin of some air-breathing teleosts.

Functional properties of myofibrils and relative stability of myosin of five teleosts Channa punctata, Clarias batrachus, M astacembalus armatus, Labeo rohita and Catla catla adapted to different breathing modes were compared. Myofibrillar contractility and m-ATPase of air-breathing organ (ABO) possessing C.punctata and C. batrachus were low and least affected by pH in the range of 7.1-8.5. However, their myosin isoforms were relatively thermostable, more soluble at sub-neutral pH values, between 0.1 to 0.15 M KCl concentrations and less susceptible to a-chymotryptic digestion. In contrast, myofibrils and myosin of water-breather major carps L. rohita and C. catla were more contractile and susceptible to pH and salt concentrations. Thus, correlation between catalytic efficiency and relative stability of myofibrils and myosin of ABO-possessing teleosts was of reverse order and magnitude, as compared to water-breathers. Interestingly, myofibrils and myosin of the behavioral air-breather M. armnatus showed intermediate properties. The specific levels of m-ATPase of all the five teleosts were in conformity with the levels of metabolic marker, the lactate dehydrogenase. The effect of chymotryptic cleavage of 94 and 173 kDa domains on ATPase, individuality of peptide maps of MyHC isomers and perturbation of phenylalanine residues by urea implicated hydrophobic residues in stabilizing myosin structure in these fish. The present study suggests two apparent evolutionary modifications of myofibrils and myosin in ABO-possessing teleosts: (i), 'down-regulation' of ATPase that explains sluggishness of such species and, (ii), more stable molecular structure to support stress of air-breathing modes of life.