Left Gluteus Maximus Muscle Research Articles

The relationship between asymmetry changes in the slope frequency of bioelectrical activity of the gluteus maximus muscles and experience in short track speed skating athletics

BACKGROUND: In short track speed skating, there is asymmetric fatigue of the gluteus maximus (GM) muscle resulting from the technique of skating. Scientific reports confirm the relationship between muscle fatigue and its change in the slope frequency of bioelectrical activity. OBJECTIVE: To investigate whether athletic experience in elite short track speed skating can distinguish the asymmetry change in slope frequency of the raw electromyographic signal (EMG) of the GM muscle, influenced by the disparity in experience between junior and senior athletes. METHODS: In the research, an elite group of short track speed skating national team athletes Junior and Senior, participated. Isometric tension GM muscle was tested using the Biering-Sorensen test. RESULTS: The study confirmed differences in the asymmetry of slope frequences EMG signal in GM muscle between juniors and seniors in short track speed skating (p⩽ 0.001). Senior athletes showed greater slope frequences in the right GM muscle (p⩽ 0.002), while juniors showed greater in the left GM muscle (p⩽ 0.008). Intergroup analysis revealed significantly meaningful differences (p⩽ 0.001) in the level of slope frequences of the right GM muscle (juniors vs. seniors), highlighting the asymmetry resulting from experience. CONCLUSIONS: Statistically significant differences in the level of slope frequences of the right gluteus maximus muscle juniors vs. seniors were demonstrated, suggesting asymmetry due to experience and skating technique.

Postural balance disorders in sarcopenia based on surface electromyography

BackgroundSarcopenia is an intrinsic factor that leads to balance disorders and falls in older adults. However, the characterization of sarcopenia-related postural balance deficits remains unclear. AimsThis study aimed to explore the balance performance and postural control strategy in older adults with sarcopenia during static stance tasks using force platforms and surface electromyography. MethodsOlder adults with right-sided dominance were recruited, including 27 adults with sarcopenia and 27 healthy counterparts. Postural sway was measured with eyes open/closed on rigid/compliant surfaces. The time- and frequency-domain indexes of bilateral lower extremity muscle activity were simultaneously recorded. ResultsThe postural sway and activity of multiple lower extremity muscles in the sarcopenia group were increased (P < 0.05). The amplitude contribution ratio of the right tibialis anterior muscle (larger in sarcopenia), co-contraction ratio of right ankle dorsiflexion (smaller in sarcopenia), and mean power frequency and median frequency of the left gluteus maximus muscle (smaller in sarcopenia) had main effects of grouping (P < 0.001, η2p = 0.06–0.10). All of them had discrimination for sarcopenia (area under the curve = 0.639–0.657, P < 0.001) and were correlated with balance function measurement in sarcopenia (|rs| = 0.22–0.44, P < 0.05). ConclusionThe results of this study suggest that older adults with sarcopenia have decreased balance function and increased cost of electrophysiology. They were found to prefer the postural strategy of dominant ankle dorsiflexion and demonstrated overactivity of the dominant tibialis anterior muscles and fatigue vulnerability of the nondominant gluteus maximus. Improvements in these postural features may have balance benefits.

Evaluation of muscle energy in isometric maintenance as an index of muscle fatigue in roller speed skating.

Roller speed skating is a discipline in which muscle fatigue plays an important role in athletes; in this work, we wanted to evaluate whether a methodological approach based on the energy required to maintain an isometric muscle contraction for one minute, indexed on the MVIC (maximum voluntary isometric contraction), i.e. % RMS/MVIC can give results similar to the frequency decay analysis/time in terms of usability for athlete training and injury prevention. Right and left gluteus maximus and vastus lateralis muscles (involved in the propulsive phase of skating ) were examined separately by surface electromyography in three competitive athletes in short-track speed skating on asphalt. The results showed an asymmetry between the right (less resistant) and left (more resistant) lower limb, in all three athletes, from the point of view of fatigue, in both investigated muscles. Furthermore, a trend in terms of fatigue resistance was found that was directly proportional to skill in both muscles studied. This can be of help in better planning the training of street speed skaters (which although similar to the discipline on ice is not completely superimposable) with the dual purpose of improving their performance and preventing injuries, often linked to the degree of right-left muscle asymmetry.

Which Comes First: Angiogenesis or Myogenesis Following Punch Biopsy Injury?

IntroductionSkeletal muscle is integral to metabolic homeostasis, movement, and breathing. The microcirculation supplies oxygen and nutrients to myofibers while removing their metabolic byproducts. Following skeletal muscle injury, damaged myofibers and capillaries regenerate to restore tissue structure and function. However, it is unknown if angiogenesis or myogenesis is preferred when blood vessels and myofibers are removed simultaneously and permitted to regenerate. Congruent with the dependence of myofiber function and survival on their microvascular supply, we hypothesized that angiogenesis precedes myogenesis during skeletal muscle regeneration following punch biopsy.MethodsThe left gluteus maximus muscle (GM) of anesthetized male and female Cdh5‐mTmG reporter mice (age, 4‐5 months) was injured by creating a hole (diameter, 2 mm) through the muscle with a biopsy punch. Mice were studied at four timepoints: uninjured control [0 days post injury (dpi)], 7 dpi, 14 dpi, 21 dpi.ResultsUsing intravital microscopy to observe the GM in anesthetized mice, regenerating microvessels grew into the biopsy zone by 7 dpi with networks traversing the residual gap by 14 dpi; nascent microvessels were perfused at 14 dpi as confirmed with fluorescent markers injected into the circulation. In contrast, myofibers were absent from the injured area at 7 dpi, began regenerating at wound edges by 14 dpi, and spanned the gap at 21 dpi. Confocal imaging and histology confirmed the presence of microvessels and absence of myofibers at 14 dpi, with both tissue components reoccupying the injured area at 21 dpi.ConclusionAngiogenesis precedes myogenesis during regeneration following punch biopsy of skeletal muscle.

Comparison of the Beta-Band Intermuscular Pool Coherence Between Chronic Non-specific Low Back Pain and Healthy Subjects

Objectives: The current study aimed to compare between the chronic non-specific low back pain (CNSLBP) and healthy subjects during four phases of the trunk flexion-extension task (standing, flexion, relaxation, and extension phases) by using pool coherence as well as pairwise coherence of Beta band Intermuscular coherence (Bb-IMC) and flexion relaxation phenomena. Methods: Twenty-four men with CNSLBP and 20 healthy men voluntarily participated in this study. All subjects performed three tests of Flexion-extension task (F-ET) while the surface electromyography (sEMGs) were recorded from the right erector spinal muscle of the lumbar region “1”, left erector spinal muscle of the lumbar region “2”, right gluteus maximus muscle”3”, left gluteus maximus muscle”4”, right hamstring muscle”5” and left hamstring muscle”6”. Accordingly, group A contains muscles 1, 4, and 6 and group B consists of muscles 2, 3, and 5. The pool coherence (PC) and the pairwise coherence (PWC) for all the above-mentioned muscles were calculated using Beta-band intermuscular coherence analysis. Thereafter, the mean pool coherence (mPC) was considered for group A and group B for four phases of F-ET in three groups as following: CNSLBP patients group, healthy subjects group and the third group included all subjects that participated in this study, whether patients or healthy and it was called the general group. Moreover, the mean pairwise coherence (mPWC) among each pair of group A and B muscles was calculated for four phases of F-ET using Bb-IMC in CNSLBP patients and healthy subjects. Results: These results indicated a high value of A mPC in the general group and healthy subjects in the flexion phase, whereas the same A mPC in CNSLBP patients was high in all phases of F-ET. On the other hand, while B mPC was high in the general group and healthy subjects in the extension phase; it was high in all phases of F-ET in CNSLBP patients; B mPC in CNSLBP patients was high in extension, standing, and flexion phases. A mPWC and B mPWC were not significantly different between CNSLBP patients and healthy subjects in all phases of F-ET. However, only A mPWC “1 - 4” and the A mPWC “4 - 6” were significantly smaller in CNSLBP patients compared to the healthy subjects in the relaxation and flexion phases, respectively. Hence, we suggest pool coherence of Bb-IMC, not pairwise coherence of Bb-IMC, to compare CNSLBP patients and healthy subjects. Conclusions: According to the present findings, we suggest using the pool coherence of Bb-IMC in the clinical examination for CNSLBP patients and studying the probable cortical effects and the effectiveness of various treatments on corticospinal tract function in CNSLBP.

DEEP NECK FLEXORS IMPACT RECTUS ABDOMINIS MUSCLE ACTIVITY DURING ACTIVE STRAIGHT LEG RAISING.

Active straight leg raising (ASLR) is commonly performed to test fundamental movement competency. Head control or positioning can affect the abdominal muscle activity during movements. To investigate whether abdominal muscle activity differs when the head is extended or when deep neck flexor (DNF) muscles are selectively activated during the ASLR. Cross-sectional. Participants were included based on the following criteria: 1) age>17 years; 2) no spinal or lower extremity pain in the prior month; 3) the vertical line of the malleolus in an elevated the lower limb resides below the knee joint line of a non-moving lower limb during ASLR and above during a passive straight leg raising in each lower limb; and 4) no history of diagnosed spinal deformities or central nervous system disorders. Participants with > 39% reference voluntary contraction in the sternocleidomastoid muscle during the craniocervical flexion test (CCFT) of 24 mmHg target were excluded from the analyses. Right ASLR was repeated in each of the following three head conditions in a random order: 1) neutral head position, 2) head extended by 25 °, and 3) CCFT maintained with a 24 mmHg target. Among the three head conditions, the relative latency for the onset of the right rectus femoris (RF) muscle during the right ASLR and the muscle activity amplitude for 50ms were compared after the onset of RF muscular activity in the following muscles: left rectus abdominis (RA), bilateral external obliques, bilateral internal obliques, and left gluteus maximus muscles. Data from 31 participants (21 women and 10 men, mean age=22.5 years) were analyzed. The relative latency of the left RA (Hedges' g = 0.39, p=.038) was higher in the CCFT condition (mean±SD=112.1ms±86.0ms) than that in the neutral head condition (82.9ms±58.6ms). However, no difference (all p>.05) was observed in other measures between the groups. In people with impaired movement competency in ASLR, head extension did not alter the abdominal muscle activities in ASLR. However, selective activation of the DNF muscles delayed the onset of RA muscle activity during the ASLR. 4.

Brothers-in-arms: Liaison between spine surgeons and plastic surgeons in wound repair after complex spine surgery

In NASSJ, Brown and Rubayi have presented an interesting case and discussion of a morbidly obese young female who had midline lumbosacral incisional dehiscence superimposed with infection following lumbopelvic fixation for complex spinopelvic trauma [1]. The authors report a successful outcome in this patient with a sliding musculocutaneous flap overlying the left gluteus maximus muscle.

Training induced fatigability assessed by sEMG in Pre-Olympic ice-skaters

The aim of this study was to investigate the size of the change and asymmetry in fatigability of gluteus maximus muscles during endurance training in short-track. The research has taken into account the position of athletes during skating and the problem of fatigue and pain in these muscles. The research covered involved eight female athletes of the Polish National Team in short track, which had been prepared to the Olympic Games in PyeongChang. The surface electromyography (sEMG) system was used to measure fatigue of right and left gluteus maximus muscles, in the modified Biering–Sorensen test. The test was conducted five times during the training: before training, after warmup, and after each of 3 series of the endurance training. Comparing the mean frequency of the surface electromyography power spectrum of the test, statistically significant reduction of the average frequency value of the right muscle from 55.61 ± 7.08 to 48.64 ± 4.48 Hz and left muscle from 58.78 ± 4.98 to 53.18 ± 4.62 Hz was reported, which prove the muscle fatigue. In subsequent series tests, the sEMG signal frequency of begin decrease more than the end of the each measurement, which determines the fatigue threshold. The size of the d Cohen effect in fatigue drops along with subsequent five tests during the training. Skaters has higher frequency reduction of the right lower limb, which indicates its greater fatigue during skateing. The fatigue and asymmetry in muscle observed in short-track has implications for training and performance.

Earlier onsets in internal oblique and gluteus maximus muscles during leg raising in Functional Movement Screen score 3 than score 1.

Active straight leg raising (ASLR) is a fundamental test and used in the Functional Movement Screen (FMS). In the ASLR of the FMS, one subgroup performs the movement correctly without any compensation (ASLR-3), whereas another subgroup has limitations in ASLR but not the passive straight leg raising (ASLR-1-SMCD). We aimed to investigate whether abdominal muscle activities in ASLR are different between individuals with ASLR-1-SMCD and ASLR-3. The relative latency of the onset of the following muscles to the right rectus femoris muscle during the right ASLR and the amplitude of activity in the following muscles for 50 msec after the onset of rectus femoris muscle activity were compared: left rectus abdominal, bilateral external oblique, bilateral internal oblique, and left gluteus maximus muscles. Data of 17 participants with ASLR-3 and 34 participants with ASLR-1-SMCD, whose sex ratio was matched to the ASLR-3 group, were analyzed. Those with ASLR-1-SMCD had statistically significant delays in the relative latency of the right internal oblique muscle (46.32±70.83 msec) and left gluteus maximus muscle (100.36±75.40 msec) muscles compared with those with ASLR-3 (right internal oblique muscle=9.75±23.07 msec, left gluteus maximus muscle=57.50±36.89 msec). However, the difference in the amplitude of activity in any muscles was not significant. The ASLR-1-SMCD group had greater relative latency of the onset of right internal oblique muscle and left gluteus maximus muscle to the onset of the right rectus femoris muscle during the right ASLR compared with the ASLR-3 group.

Asymmetrical fatiguing of the gluteus maximus muscles in the elite short-track female skaters

BackgroundAccording to research, fast skating on short distances increases functional asymmetry of leg muscles. As has been proven in many sporting disciplines, this asymmetry can increase the risk of injury. The aim of the study was to analyze the level of right and left myolectrical manifestations of fatigue asymmetry of gluteus maximus muscle in elite skaters on a short track and to compare this phenomenon to a control group. The muscles were chosen deliberately, due to their influence in maintaining the right position during training on ice.MethodsThe experiment compared a group of eight members of the Polish Women’s National Team in short track with a group of eight non-training people. The subjects did the Biering-Sorensen test, in which sEMG (surface electromyography) signal frequency was measured in the gluteus maximus muscles during an isometric contraction. Myolectrical manifestations of fatigue slopes were analyzed with a ANOVA with repeated measures. In the skaters, the myolectrical manifestations of fatigue differed between the right and the left gluteus maximus muscles. All the skaters had higher myolectrical manifestations of fatigue in the right leg. This phenomenon was not observed in the non-training subjects, who on average had similar myolectrical manifestations of fatigue in both legs.ResultsResults showed that the right and the left muscles of the skaters in the experimental group differed in myolectrical manifestations of fatigue, but this difference was non-significant in the control group.The subjects from the two groups did not differ in the myolectrical manifestations of fatigue of the left muscle, they did in the myolectrical manifestations of fatigue of the right muscle. The elite speed-track skaters had higher myolectrical manifestations of fatigue in the right muscle than the non-training subjects.ConclusionsTraining should thus be planned in a way that minimizes the risk of causing muscle myolectrical manifestations of fatigue asymmetry in skaters despite the typically asymmetrical muscle work during training on ice and competition, thus new training protocols should be developed or considered to decrease that asymmetry.Trial registrationThe tests were previously approved by the Bioethical Commission of the Chamber of Physicians in Opole. (Resolution No. 235 of 13 December 2016).

Using a hybrid approach to management of a common femoral arterial dissection

A middle-aged (fifth decade) patient was brought to the emergency department after a motorcycle collision during which the lower abdomen-to-pelvis area was trapped between a traffic sign pole and the...

Attenuated rapid onset vasodilation with greater force production in skeletal muscle of caveolin-2-/- mice.

Caveolin-2 (Cav2) is a major protein component of caveolae in membranes of vascular smooth muscle and endothelium, yet its absence alters the ultrastructure of skeletal muscle fibers. To gain insight into Cav2 function in skeletal muscle, we tested the hypothesis that genetic deletion of Cav2 would alter microvascular reactivity and depress contractile function of skeletal muscle in vivo. In the left gluteus maximus muscle (GM) of anesthetized Cav2(-/-) and wild-type (WT) male mice (age, 6 mo), microvascular responses to physiological agonists and to GM contractions were studied at 34°C. For feed arteries (FA), first- (1A), second- (2A) and third-order (3A) arterioles, respective mean diameters at rest (45, 35, 25, 12 μm) and during maximal dilation (65, 55, 45, 30 μm) were similar between groups. Cumulative dilations to ACh (10(-9) to 10(-5) M) and constrictions to norepinephrine (10(-9) to 10(-5) M) were also similar between groups, as were steady-state dilations during rhythmic twitch contractions (2 and 4 Hz; 30 s). For single tetanic contractions (100 Hz; 100, 250, and 500 ms), rapid onset vasodilation (ROV) increased with contraction duration throughout networks in GM of both groups but was reduced by nearly half in Cav2(-/-) mice compared with WT mice (P < 0.05). Nevertheless, maximal force during tetanic contraction was ∼40% greater in GM of Cav2(-/-) vs. WT mice (152 ± 14 vs. 110 ± 3 mN per square millimeter, respectively; P < 0.05). Thus, while structural and functional properties of resistance networks are well maintained in the GM of Cav2(-/-) mice, diminished ROV with greater force production reveals novel physiological roles for Cav2 in skeletal muscle.

Radiation-induced undifferentiated pleomorphic sarcoma after radiation therapy for a desmoid tumour

Radiation-induced sarcoma is a long-term complication of radiation therapy. The most common secondary neoplasia is the undifferentiated pleomorphic sarcoma, which is usually described in the deep soft tissue of the trunk or extremities. Radiation-induced sarcomas have a poor prognosis. An early diagnosis and management are needed to improve the survival rate of such patients. We presently report a case of a radiation-induced undifferentiated pleomorphic sarcoma of the left gluteus maximus muscle, which developed 25years after an initial diagnosis of aggressive fibromatosis and 21years after a tumour recurrence. This case study illustrates the risk of developing a sarcoma in a radiation field and the need for long-term follow-up after radiation therapy. Unnecessary radiation therapy, in particular in the case of benign conditions in young patients, should be avoided.

Gluteus Maximus Turnover Flap for Sacral Osteomyelitis After Radiation Therapy

Developments in radiation therapy modalities offer alternative treatments for unresectable malignant tumors in the pelvis and trunk. However, poor vascularity as a result of radiation therapy makes the treated lesion susceptible to infection, and there are no established treatments for pelvic osteomyelitis with a large dead space after radiation therapy. The authors report 2 cases of sacral osteomyelitis after radiation therapy that were treated successfully with a gluteus maximus turnover flap. To create the flap, the distal portion of the lower third of the muscle was detached from the trochanter. The distal edge of the flap was turned toward the sacral defect and sewn to the remnant of the sacrum, which filled the dead space with the muscle bulk. A 68-year-old man with a recurrent sacral chordoma was treated with carbon ion radiation therapy; however, a sacral infection developed 5 months later. Debridement and a course of antibiotics could not control the infection and did not induce sufficient formation of granulation tissue in the large and deep dead space. The turnover flap with both gluteus maximus muscles cured the deep-seated infection and closed the wound. A 58-year-old woman had sacral osteoradionecrosis with infection. A turnover flap created with the left gluteus maximus muscle controlled the infection and closed the wound after the first operation, a V-Y flap, failed. This study showed that a gluteus maximus muscle turnover flap effectively controlled infectious lesions with large and deep dead space around the sacrum.

EMG of Trunk and Lower Limb Muscles While Squatting with Different Stability and Resistance

PURPOSE: To determine the effects of squat with different stability and resistance on muscle activities. METHODS: Fourteen healthy male (age: 21 ± 2 years old, height: 176 ± 5 cm, and mass: 71 ±8 kg) performed squat. A VICON motion-analysis system was used for data collection. The RMS of EMG of rectus abdominis (RA), tensor fasciae latae (TFL), rectus femoris (RF), right tibialis anterior (RTA), left tibialis anterior (LTA),lower lumbar erector spinae (LLES), right gluteus maximus (RGMa),left gluteus maximus (LGMa), gluteus medius (GMe), and biceps femoris (BF) muscles were collected by a Trigno TM wireless EMG system when performing squat on a new six degrees of freedom platform (CAREN, with one stable and two level(A,B) of instability condition) under body weight and 30%RM(repetition maximum), respectively. The sequence of 6 conditions (SO, S30, A0, A30, BO, B30) for each subject was randomized to eliminate the possible fatigue and learning effects. A Polar heart rate monitor was applied to make sure heart rate under 100 b/min after each rest. Differences in EMG activities of the muscles were compared between S0 and the other conditions using the paired t-test. RESULTS: No significant difference was observed for most muscles EMG between unstable and stable surface (p>.05). Most of muscles EMG significantly increased when 30%RM weight load compared with the body weight load condition (p<.05, Table 1). CONCLUSIONS: Simply applying moderately unstable surface do not provide more stimulation to the superficial muscles, external weight load can effectively mobilize more muscle activity during squatting in highly resistance-trained people. The effects of external loading might not be replaced by unstable surface if the goal is to increase superficial muscle activation levels.TABLE 1: The Relative value (mean ± SD) of RMS of tested muscles under 6 conditions (N = 14)

Aging alters reactivity of microvascular resistance networks in mouse skeletal muscle

Vascular aging is associated with adrenoreceptor (AR) activation and endothelial dysfunction yet little is known of how aging affects microvascular networks in vivo. We tested the hypothesis that vasoreactivity is altered throughout resistance networks with aging. The left gluteus maximus muscle of anesthetized Young and Old (4 and 24 months) male C57BL/6 mice (n's=5–6) was superfused with saline (pH 7.4, 34°C) and diameters of the inferior feed artery (FA) and 1A, 2A, &amp; 3A arterioles imaged at 1200X. Respective maximal diameters of Young (60, 51, 35, 23 ± 3 μm) were less (P&lt;0.05) than Old (62, 55, 44, 32 ± 4 μm) for 2A and 3A. Resting tone in 2A (53 vs 35%) and 3A (66 vs 49%) was higher (P&lt;0.05) in Old vs Young. Elevating superfusion O2 from 0 to 21% constricted all vessels more (P&lt;0.05) in Young (23–45%) than Old (11–31%). Constrictions to phenylephrine (α1AR) were similar across FA and 1A (60–70%) but greater (P&lt;0.05) for 2A (98 vs 69%) and 3A (100 vs 79%) of Young; all constrictions to UK14304 (α2AR) were depressed &gt;; 30% in Old. With ACh, dilations were 20% greater in FA of Young, yet dilations of 1A (15%), 2A (75%) and 3A (100%) were greater (P&lt;0.05) in Old. Thus aging decreased O2 reactivity and blunted α2AR responses throughout resistance networks and α1AR responses in distal arterioles. Enhanced dilation in arterioles of Old reflects greater resting tone and sensitivity to endothelium‐dependent dilation in vivo. (NIH HL086483)

Effects of Various Gait Speeds on the Latissimus Dorsi and Gluteus Maximus Muscles Associated with the Posterior Oblique Sling System

[Purpose] This study investigated the effect of different gait speeds on the muscle activities of the latissimus dorsi and gluteus maximus muscles in relation to the posterior oblique sling system. [Subjects] We recruited 14 young adult males. [Methods] We measured the left latissimus dorsi muscle activity and right gluteus maximus muscle activity of all subjects while they walked on a treadmill at speeds of 1.5 km/h, 3.5 km/h and 5.5 km/h. [Results] There was a significant increase in latissimus dorsi muscle activity with a treadmill speed of 5.5 km/h compared with 1.5 km/h and 3.5 km/h. The gluteus maximus muscle activity significantly increased in the order of 1.5 km/h < 3.5 km/h < 5.5 km/h. [Conclusion] The present results indicate that arm swing connected to increasing gait speed influences the muscle activity of the lower limbs through the posterior oblique sling system.

Ostéoarthrite de hanche primitive et myosite multifocale à méningocoque B chez un enfant de 7 ans

Neisseria meningitidis is associated with severe invasive infections such as meningitis and fulminant septicemia. Septic arthritis due to N.meningitidis is rare and bone infections have been reported exceptionally. We report the case of a 7-year-old boy who presented with septic arthritis of the right hip associated with a septic location on the pelvis and pyomyositis of the adjacent muscle. Culture of the joint fluid was sterile but universal 16S polymerase chain reaction (PCR) of this fluid revealed group B N.meningitidis. Our patient had never presented any symptoms of meningitis or septicemia and blood cultures were all sterile. Despite appropriate antibiotic treatment, the course of the disease was unusually long and his status did not improve until surgical lavage of the hip was performed. Moreover, MRI imaging showed bilateral hypersignals of the adjacent muscles and revealed an abscess formation in the left gluteus maximus muscle. Presumptive diagnosis bacterial myositis was confirmed by an elevation of creatine phosphokinase in the sera up to 21-fold the normal value but the culture of the abscess, performed 10 days after initiation of antibiotics, was sterile. Despite an initially unfavorable course, this patient's status improved after surgical drainage and he fully recovered 1 month later. This observation illustrates an unusual presentation of invasive meningococcal infection. The respective roles of infection and an inflammatory phenomenon during the course of the disease are discussed. Moreover, this case emphasizes the value of PCR for bacteriological diagnosis of bone and joint infections.

A Pain in the Butt: Marginal Zone Lymphoma of the Gluteus Muscle

AbstractAbstract 5104A 75-year-old man first noted a slowly enlarging left buttock mass about one year prior to his presentation to the hematology/oncology clinic. At that time, he was evaluated at the surgical clinic and imaging studies as well as a biopsy were recommended. The patient refused and was lost to follow-up. On presentation to the hematology/oncology clinic, the patient complained of further increase in the size of the mass as well as growing discomfort in the area. Physical exam revealed a large, firm, discrete but nontender left buttock mass, measuring approximately 14 × 10 cm (Figure 1). There was no other palpable lymphadenopathy or hepatosplenomegaly, and the rest of his physical and neurologic exam was normal. A CT scan of the chest, abdomen, and pelvis was performed revealing a massively enlarged left gluteus maximus muscle measuring 14.4 × 9.7 cm with homogeneous attenuation and no drainable fluid collection that was extending into the sacrosciatic notch, sacroiliac joint, and with epidural extension into the sacral foramen (Figure 2). There were no other abnormal findings. A core needle biopsy was performed, and pathology revealed a diffuse infiltrate of small lymphocytes that was negative for CD5, CD10, CD23, bcl-6, cyclin D1, and positive for CD20 and CD43, consistent with marginal zone lymphoma (Figure 3). The patient denied weight loss, fevers, or night sweats. A bone marrow biopsy was performed and showed no evidence of lymphoma. Laboratory evaluation including a CBC, comprehensive metabolic panel, LDH, and hepatitis serologies were negative.Due to increasing discomfort and moderate difficulty in ambulation attributable to the mass, treatment comprising four cycles intravenous rituximab 375 mg/m2, cyclophosphamide 750 mg/m2, vincristine 1.4 mg/m2 given on Day 1 and oral prednisone 40 mg/m2 daily from Days 1 to 5 (R-CVP), was begun. The patient tolerated treatment well with no adverse effects. There was complete resolution of the mass after two 21-day cycles of R-CVP.Marginal zone lymphomas (MZL) are a group of distinct entities including nodal MZL, extranodal MZL, and splenic MZL. They all share a similar immunophenotype, being positive for B cell markers CD19, CD20, and CD22, and negative for CD5, CD10, and usually CD23. MZLs are often indolent malignancies and present with localized disease. Risk factors associated with the development of these malignancies include autoimmune diseases such as Sjogren's syndrome and Hashimoto's thyroiditis, and various infectious agents including Helicobacter pylori, Chlamydia psittaci, Borrelia burgdorferi, Campylobacter jejuni, and even the human immunodeficiency and hepatitis C viruses. Extranodal MZLs constitute about 5% of all Non-Hodgkin's lymphomas. Most extranodal MZL patients present with stage I or II disease and B-symptoms are uncommon. Extranodal MZLs most commonly involve the gastrointestinal tract (stomach most commonly), lung, lacrimal and salivary glands, skin, thyroid, dura, and breast where mucosa-associated lymphoid tissue is abundant. Standard treatment for extranodal MZLs has not yet been established due to the small number of studies in the literature, and thus is highly individualized. For patients with localized disease, locoregional radiation therapy is appropriate. Patients with advanced disease are managed similarly as patients with follicular lymphoma with conventional chemoimmunotherapy.Primary skeletal muscle involvement with lymphoma is exceedingly rare; most of the cases described in the literature are of the diffuse large B-cell type and is thought to carry a poor prognosis. The patient described in the case had a complete response after treatment and experienced no adverse events. Although MZL of the extra-ocular muscles have been described in the literature, to the authors' knowledge, this is the first report of marginal zone lymphoma of the gluteal muscle. [Display omitted] [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

A case of intraneural perineurioma presenting with monomelic atrophy in a child

We report the case of an 11-year-old girl who developed slowly progressive atrophy of the left lower extremity. She suffered from mild dilated cardiomyopathy of unknown cause since 4 years of age. When she was 7 years old, her family noticed that her left extremity was thinner compared to the right one. Computed tomography showed atrophy and areas of low density in the left gluteus maximus, thigh, and calf muscles. The left sciatic nerve showed gadolinium enhancement on magnetic resonance imaging. A biopsy of the left sural nerve revealed pseudo-onion bulbs. Immunohistochemical staining was positive for epithelial membrane antigen and negative for S100 protein. Electron microscopy demonstrated myelinated or unmyelinated nerve fibers surrounded by concentric layers of perineurial cells. These results indicated intraneural perineurioma. The tumor was estimated at least from the nerve root to the ankle joint. The length of nerve involvement in this patient was the highest recorded in the literatures. Intraneural perineurioma is a very rare disorder, but is tend to be found in youth. This disorder should be considered when we see children with monomelic weakness and/or atrophy.