Development of a clinical prediction score for perioperative complications following metastatic spinal surgery (PERCOM) score

Background

Spinal metastases can impair mobility, worsening the Karnofsky Performance Status (KPS). Surgery for spinal metastases has the potential to improve KPS and extend prognosis, but it is crucial to recognize the elevated risk of perioperative complications. Therefore, the development of a new scoring system to accurately predict perioperative complications in spinal metastatic surgery is essential.

Methods

We conducted a retrospective observational study with 86 patients who underwent surgical intervention for spinal metastases. Patients were divided into two groups based on the presence or absence of perioperative complications within 14 days after surgery. Various factors related to perioperative complications were assessed through univariate and multivariate analyses. We established a clinical prognostic scoring system called the Perioperative Complications following Metastatic Spinal Surgery (PERCOM) score and evaluated its precision using receiver operating characteristic (ROC) analysis.

Results

Five variables (age, KPS, primary prostate cancer, Albumin, and Hemoglobin) identified in the univariate analysis were assigned binary values of 0 or 1. The PERCOM score was then calculated for each patient by summing the individual points, ranging from 0 to 5. The optimal threshold determined by ROC curve analysis for the PERCOM score was 2 points, with a sensitivity of 86 % and a specificity of 56 %.

Conclusions

The composite PERCOM score effectively predicted perioperative complications in spinal metastasis surgery. To further validate its precision, a prospective multicenter study is needed.

Clinical features and outcomes of spine surgery in patients with ankylosing spondylitis

OBJECTIVES

The study aimed to comprehend the clinical features and outcomes of surgical treatments for spinal disorders in patients with ankylosing spondylitis (AS).

METHODS

This retrospective study enrolled patients with AS who underwent spine surgery between 2000 and 2019 in our facility.

RESULTS

Thirteen patients with AS underwent spine surgeries. The mean age was 56.2 years, and the mean disease duration was 25.1 years at the time of surgery. Nine patients had vertebral fracture, two had kyphotic deformity, and two had myelopathy due to the spinal ligament ossification. Fracture cases included five patients with secondary pseudarthrosis/delayed palsy due to conservative treatment failure. Spinal fixation was performed in all patients. Pedicle subtraction osteotomy for kyphosis and laminectomy for myelopathy were also conducted. All patients improved after surgeries. One patient with kyphotic deformity underwent additional surgery of bilateral hip prosthesis, which resulted in better spine alignment. Four cases of perioperative complications were observed.

CONCLUSION

Myelopathy was newly found as the aetiology requiring surgery in patients with AS. This summarized case series could help physicians to identify patients with surgically treatable spinal disorders among patients with AS.

Postoperative Time Course of Avulsion-Type Herniation Focused on the Development of New Modic Changes and Their Effect on Short-Term Residual Low Back Pain

STUDY DESIGN

Retrospective study.

OBJECTIVE

To investigate the characteristics of newly developing Modic changes following discectomy and their impact on residual low back pain (LBP) in the early postoperative stage of lumbar disc herniation.

METHODS

We included 96 patients who underwent microscopic discectomy. Through MRI, we assessed new developments of Modic changes and the progression of disc degeneration at the surgical level. The presence of cartilaginous endplates was evaluated using resected specimens, and the main outcome was assessed using the visual analog scale (VAS). Further, the prevalence and time course of Modic changes, and their effects on clinical outcomes in the early postoperative period were examined.

RESULTS

A new development of Modic changes was detected in 28% of cartilaginous herniations at 6 months. Modic changes were observed more frequently in patients with cartilaginous herniation than in those without cartilaginous herniation postoperatively (P < .001). The VAS scores for LBP up to 6 months were greater in patients with Modic changes (P < .001) than those without; however, no significant differences were identified in the presence or absence of Modic changes over the year follow-up. The development of Modic changes was closely associated with residual LBP at 6 months (β:0.511, P < .001).

CONCLUSIONS

Modic changes develop predominantly in patients with avulsion-type herniation than in those with annular rupture at an earlier phase after discectomy. Furthermore, disc herniation with cartilaginous endplates may be associated with a slower decrease in LBP for up to 6 months, supporting the notion that newly developing endplate changes may cause residual LBP.

Older age at surgery and postoperative leg length discrepancy are risk factors for unfavourable patient-reported outcome measures of knee tumour endoprostheses following resection for musculoskeletal tumour of the lower limb

Aims

To evaluate mid-to long-term patient-reported outcome measures (PROMs) of endoprosthetic reconstruction after resection of malignant tumours arising around the knee, and to investigate the risk factors for unfavourable PROMs.

Methods

The medical records of 75 patients who underwent surgery between 2000 and 2020 were retrospectively reviewed, and 44 patients who were alive and available for follow-up (at a mean of 9.7 years postoperatively) were included in the study. Leg length discrepancy was measured on whole-leg radiographs, and functional assessment was performed with PROMs (Toronto Extremity Salvage Score (TESS) and Comprehensive Outcome Measure for Musculoskeletal Oncology Lower Extremity (COMMON-LE)) with two different aspects. The thresholds for unfavourable PROMs were determined using anchor questions regarding satisfaction, and the risk factors for unfavourable PROMs were investigated.

Results

The thresholds for favourable TESS and COMMON were 64.8 and 70.4 points, respectively. Multivariate analysis showed that age at surgery (p = 0.004) and postoperative leg length discrepancy (p = 0.043) were significant risk factors for unfavourable TESS results, while age at surgery (p < 0.001) was a significant risk factor for unfavourable COMMON-LE results. Following receiver operating characteristic analysis, the threshold for both TESS and COMMON-LE was 29 years of age at surgery. Additionally, a leg length discrepancy of 8.2 mm was the threshold for unfavourable TESS.

Conclusion

Patients aged > 29 years at the time of surgery require appropriate preoperative counselling and adequate postoperative physical and socioemotional support. Reconstruction equivalent to the length of the resected bone can reduce the risk of functional disabilities in daily living.

Reduced Neuroinflammation Via Astrocytes and Neutrophils Promotes Regeneration After Spinal Cord Injury in Neonatal Mice

Neonatal spinal cord injury (SCI) shows better functional outcomes than adult SCI. Although the regenerative capability in the neonatal spinal cord may have cues in the treatment of adult SCI, the mechanism underlying neonatal spinal cord regeneration after SCI is unclear. We previously reported age-dependent variation in the pathogenesis of inflammation after SCI. Therefore, we explored differences in the pathogenesis of inflammation after SCI between neonatal and adult mice and their effect on axon regeneration and functional outcome. We established two-day-old spinal cord crush mice as a model of neonatal SCI. Immunohistochemistry of the spinal cord revealed that the nuclear translocation of NF-κB, which promotes the expression of chemokines, was significantly lower in the astrocytes of neonates than in those of adults. Flow cytometry revealed that neonatal astrocytes secrete low levels of chemokines to recruit circulating neutrophils (e.g., Cxcl1 and Cxcl2) after SCI in comparison with adults. We also found that the expression of a chemokine receptor (CXCR2) and an adhesion molecule (β2 integrin) quantified by flow cytometry was lower in neonatal circulating neutrophils than in adult neutrophils. Strikingly, these neonate-specific cellular properties seemed to be associated with no neutrophil infiltration into the injured spinal cord, followed by significantly lower expression of inflammatory cytokines (Il-1β, Il-6 and TNF-α) after SCI in the spinal cords of neonates than in those of adults. At the same time, significantly fewer apoptotic neurons and greater axonal regeneration were observed in neonates in comparison with adults, which led to a marked recovery of locomotor function. This neonate-specific mechanism of inflammation regulation may have potential therapeutic applications in controlling inflammation after adult SCI.

The Difference in Clinical Features between Small-Sized Soft Tissue Sarcomas and Benign Tumors

BACKGROUND

Small-sized tumors tend to be resected without thorough assessment and are often managed in a sarcoma center after a malignancy is diagnosed. The lack of knowledge about the features of smallsized sarcomas may lead to unplanned resection. The features of small-sized soft tissue sarcomas were investigated by comparing them with those of small benign soft tissue tumors.

METHODS

We included 17 soft tissue sarcoma cases (7 on the hands and feet and 10 on the limbs and trunk) with a diameter of under 2 cm. The features of small-sized sarcomas were compared to those of 39 benign soft tissue tumors with a diameter of under 2 cm and non-specific imaging findings (30 on the hands and feet and 9 on the limbs and trunk). The investigated features were age, sex, presence of pain, subjective increasing tumor size, and duration of observation.

RESULTS

When we compared the tumors in the hands and feet, those <40 years of age (5/7 [71%] vs. 8/30 [27%], p=0.03) experiencing pain (7/7 [100%] vs. 13/30 [43%], p=0.007) were more common in patients with sarcomas than in patients with benign tumors. When we compared the tumors in the limbs and trunk, there was no significant difference in all investigated features.

CONCLUSION

Although clinical features were ineffective in distinguishing malignancy in most small-sized soft tissue tumors, we should pay attention to painful tumors of the hands and feet in younger patients.

Cases requiring reoperation for recurrence of myelopathy by lamina closure after a double-door laminoplasty using a modified Kirita-Miyazaki suture method

Background

Progression of kyphosis after laminoplasty sometimes results in the recurrence of myelopathy with lamina closure. However, only a few case reports have been published on the reoperation of double-door laminoplasty using the suture method. This study investigated the incidence and clinical features of reoperation cases caused by the recurrence of myelopathy with lamina closure after double-door laminoplasty using a modified Kirita-Miyazaki suture method.

Methods

A total of 169 patients who underwent double-door laminoplasty were included in this study, with a mean follow-up duration of 6.6 years (range: 2-16). All surgeries were double-door laminoplasties in which the open lamina was sutured to the paravertebral muscle. The reoperation rate for myelopathy recurrence due to lamina closure and the associated risk factors were investigated. The risk factors included age, history, cervical alignment, C2-7 lordosis, the cervical sagittal vertical axis, and C7 slope.

Results

The reoperation rate for recurrence of myelopathy by lamina closure was 3.0% (5/169). All patients showed kyphosis progression after surgery; the spinal cord was more compressed by closed lamina than before the initial surgery. The reoperation group had more patients with neuromuscular or psychiatric disorders (60% [3/5] vs. 2% [4/164]; p < 0.001), kyphotic alignments (60% [3/5] vs. 10% [16/164]; p < 0.001), and cases with less than -10° of C2-7 lordosis (60% [3/5] vs. 7% [11/164]; p < 0.001).

Conclusions

Double-door laminoplasty with the suture method may not be suitable for patients with a neuromuscular or psychiatric disease or those with preoperative C2-7 lordosis less than -10°.

Macrophages play a leading role in determining the direction of astrocytic migration in spinal cord injury via ADP-P2Y1R axis

After spinal cord injury (SCI), inflammatory cells such as macrophages infiltrate the injured area, and astrocytes migrate, forming a glial scar around macrophages. The glial scar inhibits axonal regeneration, resulting in significant permanent disability. However, the mechanism through which glial scar-forming astrocytes migrate to the injury site has not been clarified. Here we show that migrating macrophages attract reactive astrocytes toward the center of the lesion after SCI. Chimeric mice with bone marrow lacking IRF8, which controls macrophage centripetal migration after SCI, showed widely scattered macrophages in the injured spinal cord with the formation of a huge glial scar around the macrophages. To determine whether astrocytes or macrophages play a leading role in determining the directions of migration, we generated chimeric mice with reactive astrocyte-specific Socs3^-/- mice, which showed enhanced astrocyte migration, and bone marrow from IRF8^-/- mice. In this mouse model, macrophages were widely scattered, and a huge glial scar was formed around the macrophages as in wild-type mice that were transplanted with IRF8^-/- bone marrow. In addition, we revealed that macrophage-secreted ATP-derived ADP attracts astrocytes via the P2Y1 receptor. Our findings revealed a mechanism through which migrating macrophages attract astrocytes and affect the pathophysiology and outcome after SCI.

Destructive cervical spondylitis due to Cutibacterium acnes with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome: A case report

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a spectrum of heterogeneous diseases commonly recognised by skin and osteoarticular lesions. There have been reports of some surgical cases of the progressive, destructive spondylitis associated with SAPHO syndrome, wherein the destructive spondylitis was considered to have developed due to the progression of spondylitis with SAPHO syndrome as the pathogenic bacteria were not isolated. We herein report a surgical case of destructive cervical spondylitis associated with SAPHO syndrome. A 54-year-old woman with a history of palmoplantar pustulosis suffered severe neck pain for 6 months. Radiography and computeed tomography showed sclerosed and collapsed cervical vertebrae, and the patient was referred to our hospital for further evaluation and management upon suspicion of infection or spondylitis with SAPHO syndrome. For the severe neck pain and progressive destruction of cervical vertebrae, we performed posterior fusion surgery with subsequent anterior fusion. Cutibacterium acnes (C. acnes) was isolated by enrichment culture with thioglycolate broth from both the anterior and the posterior tissue samples. We diagnosed pyogenic spondylitis secondary to C. acnes infection and administered doxycycline for 6 weeks after the first surgery. The neck pain was resolved and cervical fusion was achieved one year postoperatively. C. acnes infection could elicit destructive spondylitis. An enrichment culture should be performed to isolate the pathogenic bacteria in cases of destructive spondylitis with SAPHO syndrome.

Zinc chelator treatment in crush syndrome model mice attenuates ischemia-reperfusion-induced muscle injury due to suppressing of neutrophil infiltration

In crush syndrome, massive muscle breakdown resulting from ischemia-reperfusion muscle injury can be a life-threatening condition that requires urgent treatment. Blood reperfusion into the ischemic muscle triggers an immediate inflammatory response, and neutrophils are the first to infiltrate and exacerbate the muscle damage. Since free zinc ion play a critical role in the immune system and the function of neutrophils is impaired by zinc depletion, we hypothesized that the administration of a zinc chelator would be effective for suppressing the inflammatory reaction at the site of ischemia-reperfusion injury and for improving of the pathology of crush syndrome. A crush syndrome model was created by using a rubber tourniquet to compress the bilateral hind limbs of mice at 8 weeks. A zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)-ethylenediamine (TPEN) was administered immediately after reperfusion in order to assess the anti-inflammatory effect of the chelator for neutrophils. Histopathological evaluation showed significantly less muscle breakdown and fewer neutrophil infiltration in TPEN administration group compared with control group. In addition, the expression levels of inflammatory cytokine and chemokine such as IL-6, TNFα, CXCL1, CXCL2, CXCR2, CCL2 in ischemia-reperfusion injured muscle were significantly suppressed with TPEN treatment. Less dilatation of renal tubules in histological evaluation in renal tissue and significantly better survival rate were demonstrated in TPEN treatment for ischemia-reperfusion injury in crush syndrome. The findings of our study suggest that zinc chelators contributed to the resolution of exacerbation of the inflammatory response and attenuation of muscle breakdown in the acute phase after crush syndrome. In addition, our strategy of attenuation of the acute inflammatory reaction by zinc chelators may provide a promising therapeutic strategy not only for crush syndrome, but also for other diseases driven by inflammatory reactions.

Shape Factor of the Spinal Cord: A Possible Predictor of Surgical Outcome for Intradural Extramedullary Spinal Tumors in the Thoracic Spine

STUDY DESIGN

Retrospective diagnostic analysis.

OBJECTIVES

To establish a new predictor of surgical outcome after surgery for intradural extramedullary spinal tumor (IDEMT) in the thoracic spine, we introduced shape factor (SF), a mathematical description of the morphology of the spinal cord. SF was calculated by dividing object area by the square of perimeter.

MATERIALS AND METHODS

Forty-three consecutive patients with IDEMT, detected by magnetic resonance imaging at the thoracic level with myelopathic signs, were included. Preoperative transverse cross-sectional area (CSA) and perimeter of the spinal cord (perimeter) at the level of maximal compression were measured. SF was calculated as 4π × CSA/(perimeter)². The association between clinicoradiological factors and surgical outcome of IDEMT was statistically analyzed.

RESULTS

Mean CSA, perimeter, and SF were 27.8 ± 15.8 mm², 28.8 ± 6.1 mm, and 0.385 ± 0.14, respectively. A histogram distribution revealed that perimeter and SF, but not CSA, fit the normal distribution. The patients were subdivided into 2 groups according to postoperative modified Japanese Orthopedic Association Score (mJOA). [group F (favorable): n = 32, mJOA ≥ 9; group UF (unfavorable): n = 11, mJOA < 9). Group UF had significantly lower mean CSA and SF. In univariate analysis of possible predictive factors for IDEMT surgery, greater age, lower preoperative mJOA, and lower SF were significantly associated with unfavorable outcome. In multivariate analysis, lower SF was the only significant predictor of postoperative outcome (odds ratio = 2.66, 95% CI 1.10-6.39, p = 0.0115).

CONCLUSION

Measurements of CSA and perimeter, followed by calculation of SF, may provide valuable quantitative information for the outcome of surgery for IDEMT.

The Posterolaterally Oriented and Laterally Downward Sloping Facet Joint Is a Risk Factor for Degenerative Cervical Spondylolisthesis and Myelopathy

Introduction

Facet joints are anatomical structures that are known to be crucial for determining spinal biomechanical motion; however, the potential relationship between facet orientation and the development of cervical spondylolisthesis remains unclear. Thus, in this study, we aimed to explore the relationship between facet orientation and cervical spondylolisthesis as well as myelopathy.

Methods

Facet orientation in the cervical spine was investigated using computed tomography in 103 patients with cervical myelopathy, and facet inclination was measured on axial, coronal, and sagittal reconstructed images. Patients were divided into anterolisthesis, retrolisthesis, and no spondylolisthesis groups at each intervertebral level (C2/3-C6/7 levels).

Results

Facet joints in the anterolisthesis and retrolisthesis groups tended to slope posterolaterally and downward laterally compared with those in the no spondylolisthesis group at C3/4, C4/5, and C5/6 levels (P<0.001).

Conclusions

The posterolaterally oriented and laterally downward sloping facet at C3/4 and C4/5 levels may be a risk factor for the development of cervical spondylolisthesis as well as symptomatic myelopathy.

Long-term outcome after en bloc resection and reconstruction of the spinal column and posterior chest wall in the treatment of malignant tumors

BACKGROUND

Malignant tumors occurring around both the spinal column and posterior chest wall are uncommon. Surgical resection of chest wall tumors adjacent to the spinal column is still challenging due to the surrounding anatomical structures. The purpose of the present study was to evaluate the long-term outcomes of surgical management in malignant tumors involving the spinal column and posterior chest wall.

METHODS

Between 1999 and 2007, 10 consecutive patients underwent en bloc resection combined with the posterior chest wall in the treatment of malignant tumors around the spinal column. There were 6 males and 4 females with a mean age at the surgery of 40.9 years old (range, 14-62 years old). The mean postoperative follow-up period was 159.7 months (range, 84-245 months). The clinical history, physical examination, laboratory data, radiological findings, and operative findings for each patient were retrospectively reviewed.

RESULTS

All surgeries were performed via a combined anterior and posterior approach. The mean numbers of partially resected vertebrae and ribs were 3.1 and 4.1, respectively. Lower or upper lobectomy was performed in four patients, and the diaphragm was partially resected in two patients. The surgical margin was wide in seven patients and marginal in two patients. Although five patients had postoperative respiratory problem, all patients improved immediately without life-threatening complications. There were no patients with respiratory insufficiency after surgery. One patient with osteosarcoma died of lung metastases 99 months after surgery. At the final follow-up, only one patient had local recurrence, five had been continuously disease-free, and three were alive with no evidence of disease.

CONCLUSIONS

En bloc resection and reconstruction in selected patients with malignant tumors involving both the spinal column and posterior chest wall demonstrated good long-term results for local control and the respiratory function.

Efficacy and safety of tranexamic acid in patients undergoing surgery for bone and soft tissue tumors: a propensity score matching analysis

Objective

The aim of this study was to investigate the efficacy and safety of tranexamic acid in patients undergoing surgery for bone and soft tissue tumors.

Methods

Data were retrospectively collected from 454 consecutive patients with bone and soft tissue tumors who underwent open biopsy, marginal resection, curettage or wide resection between January 2017 and December 2018. We performed propensity score matching of patients who received tranexamic acid with those who did not. The primary outcome variables were intra-operative, peri-operative and estimated blood loss (IBL, PBL and EBL, respectively).

Results

Tranexamic acid (+) and tranexamic acid (−) groups were defined according to whether patients received tranexamic acid or not. Among the 454 patients, open biopsy was performed in 102, marginal resection in 175, curettage in 54 and wide resection in 123. Intra-operative blood loss was significantly lower in the tranexamic acid (+) group than in the tranexamic acid (−) group for both marginal and wide resection (marginal resection: 17.3 vs. 70.3 g, respectively, P = 0.045; wide resection: 128.8 vs. 273.1 g, respectively, P = 0.023). Peri-operative blood loss and estimated blood loss were also significantly lower in the tranexamic acid (+) group for wide resection (peri-operative blood loss: 341.5 vs. 686.5 g, respectively, P = 0.0039; estimated blood loss: 320.7 vs. 550.6 ml, respectively, P = 0.030). No venous thromboembolism occurred in either group.

Conclusion

This study suggests that TXA administration safely and effectively reduces blood loss, in particular for wide resection, with no increase in the rate of adverse events.

Clinical features of multiple spinal schwannomas without vestibular schwannomas

BACKGROUND

Multiple spinal cord tumors in a single patient are very rare and most often seen in cases of neurofibromatosis and associated disorders. Schwannomatosis, which is characterized by the development of multiple schwannomas without vestibular schwannomas, has been newly defined as a distinct form of neurofibromatosis. The purpose of the present study was to describe and review the clinical and radiological features and the management of patients with multiple spinal schwannomas without vestibular schwannomas.

METHODS

Between 1986 and 2016, 19 patients with multiple spinal schwannomas without vestibular schwannoma were diagnosed and treated. Of the 19 patients, 13 were males, and 6 were females. The mean age at the first surgery for spinal schwannoma was 45.2 years old. The mean follow-up period was 123.4 months. The clinical features and radiological findings of the patients with multiple spinal schwannomas were retrospectively reviewed.

RESULTS

Among the 19 patients, there were more than 140 spinal schwannomas. The most common area of spinal schwannoma was the thoracolumbar-lumbar region. Initial symptoms and chief complaints caused by spinal schwannomas were primarily pain in the trunk or extremities in 17 (89.5%) of 19 patients. More than 60 spinal schwannomas were surgically resected. Multiple spinal surgeries were required in six patients. In all 19 patients, surgical treatment has provided successful relief of symptoms and neurological recovery.

CONCLUSIONS

Surgical treatment was safe and effective in patients with multiple spinal schwannomas without vestibular schwannomas. After surgery, we recommend that all patients be followed with magnetic resonance imaging to monitor for asymptomatic tumors or detect new tumors early.

An Analysis of 20 Cases of Radiation-Associated Sarcoma, Including 4 Cases Treated by Carbon Ion Radiotherapy

Introduction Radiation-associated sarcoma (RAS) is one of the most life-threatening complications associated with the treatment of malignant neoplasms. Because all RAS patients have a history of radiotherapy, there have been no effective treatment options when RAS is not completely resected. Methods We retrospectively reviewed 20 RAS patients, including 4 unresectable cases treated by carbon ion radiotherapy (CIRT). Results The primary diseases targeted by radiotherapy included malignant lymphoma (n=4), cervical cancer (n=3), pharyngeal cancer (n=3), breast cancer (n=2), lung cancer (n=1), rectal cancer (n=1), maxillary cancer (n=1), synovial sarcoma (n=1), and benign neoplasms (n=4). The histological diagnoses of RAS included osteosarcoma (n=8), leiomyosarcoma (n=3), undifferentiated pleomorphic sarcoma (n=3), rhabdomyosarcoma (n=1), angiosarcoma (n=1), malignant peripheral nerve sheath tumor (n=1), spindle cell sarcoma NOS (n=1), and sarcoma not further specified (n=2). The median survival time from the diagnosis of RAS was 26 months. Eleven patients underwent surgery. Five of these patients achieved a continuous disease free status or showed no evidence disease. Four patients underwent CIRT. One of these patients with leiomyosarcoma achieved a continuous disease free status, and the other patient with osteosarcoma achieved a partial response. On the other hand, 2 patients experienced Grade 3 toxicities that required surgical treatment. Conclusion RAS originates from various types of diseases that are treated by radiotherapy and shows diverse pathological features. Complete resection achieves a good prognosis. CIRT can be an effective and feasible option for unresectable RAS.

Does the Use of Peripheral Immune-Related Markers Indicate Whether to Administer Pazopanib, Trabectedin, or Eribulin to Advanced Soft Tissue Sarcoma Patients?

Pazopanib, trabectedin, and eribulin are administered for the treatment of soft tissue sarcomas (STSs); however, there is little consensus on which agent should be preferentially used in a clinical setting. This study assessed whether peripheral immune-related markers served as a useful reference when selecting pazopanib, trabectedin, or eribulin. This study included 63 patients who were administered pazopanib, trabectedin, or eribulin for advanced STSs between March 2015 and December 2020. Patients were divided into three groups based on the first drug administered among these three drugs. Differences in overall survival (OS) or progression-free survival (PFS) among the three groups were analyzed. OS showed no significant differences among the drugs administered first. For patients with low neutrophil-to-lymphocyte ratio (NLR), the OS of patients administered pazopanib as the first choice was shorter than the others (hazard ratio [HR] = 9.53, 95% confidence interval [CI] = 1.94–18.13, p = 0.0018). In the low platelet-to-lymphocyte ratio (PLR) subgroup, the OS of the patients administered eribulin for the first choice was longer than that of the others (HR = 0.32, 95%CI = 0.10–0.98, p = 0.046). Therefore, NLR and PLR might be used as prognostic indicators to dictate whether STS patients receive pazopanib, trabectedin, or eribulin.

Association between female urinary urgency and aponeurotic ptosis: Results from a community-based cross-sectional study in Japan

AIMS

To investigate the relationship between urinary urgency (UU) and aponeurotic ptosis (AP) in a health promotion project.

METHODS

This cross-sectional study analyzed 658 women in Aomori, Japan. The presence of UU was evaluated using the Overactive Bladder Symptom Score. The distance from the light reflex on the cornea to the upper eyelid (margin reflex distance-1 [MRD-1]) was measured. AP was defined as MRD-1 of less than 2.0 mm. The daily salt intake amount was estimated using the dietary questionnaire. Daily salt intake was defined as excessive if it was 10 g/day or higher. Independent factors of UU and AP were analyzed via multivariable logistic regression model.

RESULTS

The number of women with UU and AP was 193 and 65, respectively. Similar background differences were observed in age, cardiovascular disease history, renal function, hypertension, diabetes mellitus, dyslipidemia, and daily salt intake between participants with UU and those with AP. Participants with UU had a higher prevalence of AP (19% vs. 6.2%) than those without. Moreover, more than 50% of the women with AP experienced UU. Multivariable logistic analysis on UU showed that age (≥65 years), diabetes mellitus, daily salt intake (≥10 g/day), and AP (odds ratio, 2.07, p = .014) were independent factors. Multivariable analysis on AP revealed that age (≥65 years), hypertension, daily salt intake (≥10 g/day), and UU were independent factors.

CONCLUSIONS

AP was an independent indicator of UU, in addition to excessive daily salt intake. Women with AP may tend to intake excessive salt and experience UU.

Overcorrection of fractured vertebrae increases the incidence of adjacent fractures after balloon kyphoplasty: A retrospective study

Purpose

To investigate whether the correction amount by balloon kyphoplasty (BKP) is associated with the incidence of adjacent vertebral fractures (AVF).

Methods

Data from 61 patients without and 25 patients with AVF were analyzed. A linear regression model was used between vertebral instability and corrected angle or height to divide patients into the overcorrection and undercorrection groups.

Results

Vertebral fractures overcorrected for instability led to a higher incidence rate of AVF [42.4% and 46.9% with overcorrection vs. 10.7% and 13.3% with undercorrection for angle and height, respectively].

Conclusions

Overcorrection of fractured vertebrae may associate with the increased incidence of AVF.

Radiographic and Clinical Results of C1 Laminoplasty for the Treatment of Compressive Myelopathy

Study Design

Case series.

Purpose

To evaluate the radiographic and clinical results of C1 laminoplasty without fusion.

Overview of Literature

C1 laminectomy has been the standard procedure for decompression at the C1 level. However, there have been some reports of trouble cases after C1 laminectomy. C1 laminoplasty might be superior to C1 laminectomy with regard to maintaining the original C1 anatomical shape, preventing compression from the posterior soft tissue, and ensuring an adequate bone-grafting site around the C1 posterior part if additional salvage fusion surgery is necessary afterward.

Methods

Seven patients with spinal cord compression without obvious segmental instability at the C1/2 level treated by C1 laminoplasty were included. The indication of C1 laminoplasty was same as that of C1 laminectomy. C1 laminoplasty was performed in the same way as subaxial double-door laminoplasty. The imaging findings were evaluated using X-ray, computed tomography, and magnetic resonance imaging. The clinical results were evaluated using the Japanese Orthopaedic Association (JOA) Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) and JOA score. Peri- and postoperative complications were also investigated.

Results

No patient showed increased C1/2 segmental instability after the surgery. The mean pre- and postoperative JOA scores were 8.6 and 11.7, respectively. The mean recovery rate was 40.2%. The effective rate in the JOACMEQ was 50% for the cervical spine function, 33% for the upper extremity function, 50% for the lower extremity function, 17% for the bladder function, and 17% for the quality of life. No major complication that seemed to be unique to C1 laminoplasty was observed over a period of about 4 years follow-up.

Conclusions

C1 laminoplasty for patients without obvious segmental instability might be a viable alternative procedure to C1 laminectomy.

Post-carbon-ion radiotherapy vertebral pathological fractures in upper cervical primary malignant spinal tumors treated by occipito-cervical fusion

PURPOSE

To describe the characteristic features of post-carbon-ion radiotherapy (CIRT) vertebral pathological fractures (VPFs) in upper cervical primary malignant spinal tumors (PMSTs) treated by occipito-cervical (OC) fusion.

METHODS

OC fusion was performed for three consecutive patients with post-CIRT VPFs. The clinical results and imaging findings, including bone single-photon emission computed tomography (SPECT)/CT were prospectively collected.

RESULTS

No surgery-related wound complication and surgical site infection were noted. One patient experienced re-fracture and displacement of dens with the loosening of occipital screws and was treated by posterior revision surgery. At the final follow-up, all patients were alive without evidence of disease, and the solid OC fusion was confirmed. Bone SPECT/CT clearly revealed the effect of CIRT on bone turnover in the irradiated field.

CONCLUSION

The OC fusion with autologous bone grafts was a reliable option for the treatment of post-CIRT VPCs in the patients with upper cervical PMSTs. In addition, evaluation of the bone turnover at the irradiated field by bone SPECT/CT would help surgeons select an effective plan of care, such as fusion level and postoperative care.

The effectiveness of a percutaneous endoscopic approach in a patient with psoas and epidural abscess accompanied by pyogenic spondylitis: a case report

Background

Psoas or epidural abscesses are often accompanied by pyogenic spondylitis and require drainage. Posterolateral percutaneous endoscopic techniques are usually used for hernia discectomy, but this approach is also useful in some cases of psoas or lumbar ventral epidural abscess. We here report a case of psoas and epidural abscesses accompanied by pyogenic spondylitis that was successfully treated by percutaneous endoscopic drainage.

Case presentation

Our patient was a 57-year-old Japanese woman who had been receiving chemotherapy for inflammatory breast cancer and who became unable to walk due to lower back and left leg pain. She was transported as an emergency to another hospital. Magnetic resonance imaging revealed psoas and epidural abscesses accompanied by pyogenic spondylitis, and methicillin-resistant Staphylococcus aureus was detected in a blood culture. Drainage of the psoas abscess was performed under echo guidance, but was not effective, and she was transferred to our institution. We performed percutaneous endoscopic drainage for the psoas and epidural abscesses. Immediate pain relief was achieved and the inflammatory reaction subsided after 8 weeks of antibiotic therapy with daptomycin.

Conclusions

Percutaneous endoscopy allowed us to approach the psoas and epidural abscesses directly, enabling the immediate drainage of the abscesses with less burden on the patient.

Kyphosis Progression after Balloon Kyphoplasty Compared with Conservative Treatment

Study Design

Retrospective cohort study (level of evidence: 4).

Purpose

To demonstrate the effects of balloon kyphoplasty (BKP) on prevention of kyphosis progression.

Overview of Literature

Kyphoplasty can correct local kyphosis (fractured vertebra), but its efficacy is attenuated by adjacent fracture and/or disc height reduction with endplate damage. With these attenuating factors incorporated, a comparison between BKP and conservative treatment is necessary to verify the effect of BKP on kyphosis correction.

Methods

This study retrospectively analyzed 129 patients treated conservatively and 95 treated with BKP in our institution. The rate of new adjacent fracture occurrence was determined using Kaplan–Meier analysis. We examined the progression of local kyphosis in patients who underwent lateral X-ray after 1 year. Local kyphosis was measured as an angle between higher end plate of the vertebra above and lower end plate of the vertebra below the fractured vertebra. The comparison included 45 patients treated conservatively and 58 treated with BKP.

Results

The incidence of new adjacent fracture at 1 year was 7.3% in the conservative treatment group and 23.2% in the BKP group (p<0.001), while the progression of local kyphosis at 1 year was 5.7°±4.7° and 3.2°±4.6°, respectively (p=0.01). Relative to conservative treatment, local kyphosis did not progress after BKP, despite the higher incidence of adjacent fracture. Local kyphosis progressed in cases with adjacent fracture compared with those without adjacent fracture (6.0°±4.3° vs. 2.1°±4.3°, p=0.003), and fractured vertebral instability was found to be a risk factor for adjacent fracture in BKP.

Conclusions

Compared with the conservative treatment, BKP suppressed the progression of local kyphosis. However, an adjacent fracture attenuated the BKP correction and was more frequently seen in patients with unstable vertebral fractures.

Clinical Outcome and Prognostic Factors of Malignant Spinal Dumbbell Tumors

Introduction

To investigate the clinical outcome and prognostic factors of malignant spinal dumbbell tumors (m-SDTs).

Methods

We retrospectively reviewed the clinical outcome of 22 consecutive cases of m-SDTs and analyzed the prognostic factors associated with worse outcome.

Results

Nineteen of the 22 cases were managed with surgery (86%), and gross total resection (GTR) was achieved in four cases (21%). The duration of overall survival (OS) ranged from 3 to 140 months, with a median survival time of 15.3 months. The 5 year OS rate was 55.6%. In multivariate analysis, histological subtype (high-grade malignant peripheral nerve sheath tumor) (hazard ratio [HR] 14.9, p = 0.0191), GTR (HR 0.07, p = 0.0343), and presence of local recurrences (HR 11.2, p = 0.0479) were significant and independent predictors of OS.

Conclusions

On the basis of clinical data, we propose that GTR and prevention of local recurrence may improve the clinical outcome of m-SDTs.

Effect of cartilaginous endplates on extruded disc resorption in lumbar disc herniation

Objective

The aim of this study was to investigate the clinicopathologic features of lumbar disc herniation (LDH) with endplate degeneration and the association between cartilaginous fragments and inflammatory response to the herniated disc.

Summary of background data

LDH often involves hyaline cartilage fragments pulled from the vertebral endplates. Modic changes are closely associated with LDH that contains hyaline cartilage, and cartilaginous endplates seem to affect resorption of the herniated disc.

Methods

A total of 78 patients who underwent microscopic discectomy between 9 and 16 weeks after an occurrence of LDH were reviewed. Modic changes, disc degeneration, high-intensity zone, and vertebral corner defect were evaluated using magnetic resonance imaging (MRI). Histopathological observations of cartilaginous endplates and inflamed granulation tissue in the herniated disc were made. In cases with inflamed granulation tissue, neovascularization and macrophage infiltration were also evaluated using immunohistochemical analysis.

Results

Modic changes were observed in approximately one-third of the patients (26 cases: type 1, 7; type 2, 17; and type 3, 2). Cartilaginous endplates were observed in 32 cases (41%) and in the majority of cases with Modic changes compared with cases without Modic changes (65%, p = 0.001). Although inflamed granulation tissue was observed in 60 cases (77%), no significant differences were detected in patient age and the composition of the herniated material. Immunohistochemical analysis showed that fewer CD34-positive capillaries and CD68-positive cells were found in cases with cartilaginous fragments compared with those without cartilaginous fragments (p < 0.001). In addition, a higher immunoreactivity to CD34 and CD68 was found in herniated discs <25% of whose area was occupied by cartilaginous endplates compared with discs whose area was occupied at 25% or more (p < 0.001).

Conclusion

There is an association between LDH with endplate degeneration and cartilaginous herniation, with Modic type 2 predominating. Furthermore, neovascularization and macrophage infiltration, especially if the amount of cartilage is high, are likely to be less frequent in cartilaginous herniation, leading to failure in the spontaneous remission of clinical symptoms.

The neurological outcome of radiotherapy versus surgery in patients with metastatic spinal cord compression presenting with myelopathy

PURPOSE

While radiotherapy is generally an acceptable treatment for metastatic spinal cord compression, surgical intervention is controversial due to the invasiveness and diversity of diseases in the patients being considered. The ideal treatment, therefore, depends on the situation, and the most acute treatment possible is necessary in patients presenting with myelopathy. We compared the neurological outcomes between radiotherapy and surgery in patients with metastatic spinal cord compression presenting with myelopathy.

METHODS

A total 54 patients with metastatic spinal cord compression presenting with myelopathy treated in our institution between 2006 and 2016 were analyzed retrospectively. Twenty patients were selected by radiotherapy alone (radiation group), and 36 patients were selected by decompression and stabilization surgery with or without radiotherapy (surgery group). The neurological outcomes and complications were compared between the two treatment groups.

RESULTS

Seven patients initially in the radiation group underwent surgery because of a substantial decline in their motor strength during radiotherapy. One of the remaining 13 patients (8%) in the radiation group and 30 of the 34 patients (88%) in the surgery group showed improvement in their neurological symptoms (P < 0.01). One patient (8%) in the radiation group and 21 patients (62%) in the surgery group were ambulatory after treatment (P < 0.01). There were no major complications related to radiotherapy, but surgery-related complications occurred in 9 of 34 (26%) patients, and 6 (18%) patients needed reoperation.

CONCLUSIONS

Surgical decompression and stabilization may be required to improve the neurological function in patients with metastatic spinal cord compression presenting with myelopathy. However, the high rate of complications associated with surgery should be taken into consideration.

Calcium pyrophosphate dihydrate crystal deposition disease of the spinal dura mater: a case report

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is characterized by the accumulation of CPPD crystal in articular and periarticular tissues, but CPPD crystal deposition along the spinal dura mater has not been previously reported. We report a 54-year-old male presenting with progressive neck pain and numbness of the extremities. CT showed diffuse dorsal epidural calcification from C3-T6 which resulted in spinal canal stenosis. On MR imaging, the lesion was hypointense on both T₁ and T₂ weighted images. From these findings, CPPD crystal deposition in the ligamentum flavum was suspected preoperatively. Biopsy at the level of C5-6 were performed to confirm the diagnosis. Perioperative and histopathological findings revealed that CPPD crystals were deposited along the dorsal dura mater, not in the ligamentum flavum. We firstly report the CT and MR imaging features of a possible new concept in the differential diagnosis of CPPD crystal deposition disease.

Metabolic Tumor Volume by 18F-FDG PET/CT Can Predict the Clinical Outcome of Primary Malignant Spine/Spinal Tumors

BACKGROUND AND PURPOSE

Primary malignant spine/spinal tumors (PMSTs) are rare and life-threatening diseases. In this study, we demonstrated the advantage of volume-based 18F-FDG PET/CT metabolic parameter, metabolic tumor volume (MTV), for assessing the aggressiveness of PMSTs.

MATERIALS AND METHODS

We retrospectively reviewed 27 patients with PMSTs and calculated SUVmax, MTV, and total lesion glycolysis (TLG) to compare their accuracy in predicting progression-free survival (PFS) and overall survival (OS) by receiver operating characteristic (ROC) curve analysis. Univariate and multivariate analyses were used to compare the reliability of the metabolic parameters and various clinical factors.

RESULTS

MTV exhibited greater accuracy than SUVmax or TLG. The cut-off values for PFS and OS derived from the AUC data were MTV 45 ml and 83 ml and TLG 250 SUV⁎ml and 257 SUV⁎ml, respectively. MTV above cut-off value, but not TLG, was identified as significant prognostic factor for PFS by log-lank test (p = 0.04). In addition, MTV was the only significant predictive factors for PFS and OS in the multivariate analysis.

CONCLUSIONS

MTV was a more accurate predictor of PFS and OS in PMSTs compared to TLG or SUVmax and helped decision-making for guiding rational treatment options.

Subchondral fracture of the femoral head after acetabular fracture: a case report

INTRODUCTION

Preventing post-traumatic osteoarthritis is a challenging problem following acetabular fracture. Progressive osteoarthritis is considered to be caused by an irregular articular surface of the acetabular roof or cartilage injury, but little is known about the pathogenesis of collapse of the femoral head after acetabular fracture. We report a case of post-traumatic osteoarthritis after acetabular fracture in which subchondral fracture of the femoral head contributed to the progressive collapse of the femoral head and osteoarthritis. To the best of our knowledge, there has been no previous report of subchondral fracture of the femoral head after acetabular fracture.

CASE PRESENTATION

A 58-year-old Japanese man fell from a ladder. He was diagnosed with a left acetabular fracture, which was managed conservatively. He developed left coxalgia six months after injury and was seen at our institution one year after the onset of pain. The left acetabular fracture had fused, but his left femoral head had collapsed. The images at the time of injury showed a fracture of the acetabular roof, and an approximately 2mm step-off existed in the articular surface. Retrospective evaluation of the plain radiographs and computed tomography images showed that his femoral head had progressively collapsed. Our patient underwent total hip arthroplasty. Histopathologic findings demonstrated that the collapse of his femoral head was caused by a subchondral fracture of his femoral head.

CONCLUSION

Our experience with this case indicates that in addition to post-traumatic osteonecrosis, subchondral fracture may need to be considered in cases with progressive collapse of the femoral head after acetabular fracture.

miR-125b develops chemoresistance in Ewing sarcoma/primitive neuroectodermal tumor

Background

Diverse functions of microRNAs (miRNAs), including effects on tumorigenesis, proliferation, and differentiation, have been reported, and several miRNAs have also been demonstrated to play an important role in apoptosis. In this study, we investigated the possible role that miRNAs may play in the development of chemoresistance in Ewing sarcoma/primitive neuroectodermal tumor (EWS).

Methods

We screened doxorubicin (Dox)-resistant EWS cells to identify any distinct miRNA sequences that may regulate the chemoresistance of EWS cells. The effects of miRNAs were evaluated using a chemosensitivity assay. The possible target genes of the miRNAs were predicted using a web-based prediction program.

Results

We found miR-125b to be upregulated in two different Dox-resistant EWS cell lines. The upregulation of miR-125b was also confirmed in the EWS tumors having survived chemotherapy regimen which includes doxorubicin. When miR-125b was knocked down in EWS cells, both the Dox-resistant and parental cells showed an enhanced sensitivity to doxorubicin, which was associated with the upregulation of the pro-apoptotic molecules, p53 and Bak. Inversely, the overexpression of miR-125b in parental EWS cells resulted in enhanced drug resistance, not only to doxorubicin, but also to etoposide and vincristine.

Conclusions

Our findings suggest that miR-125b may play a role in the development of chemoresistance in EWS by suppressing the expression of the apoptotic mediators, such as p53 and Bak.

Prognostic significance of AKT/mTOR and MAPK pathways and antitumor effect of mTOR inhibitor in NF1-related and sporadic malignant peripheral nerve sheath tumors

PURPOSE

Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with poor prognosis. MPNSTs occur frequently in patients with neurofibromatosis type 1 (NF1), in which NF1 gene deficiency leads to Ras hyperactivation. Ras activation causes the subsequent activation of the AKT/mTOR and Raf/MEK/ERK pathways and regulates cellular functions. However, the activation profiles of the AKT/mTOR and MAPK pathways in MPNSTs are poorly understood. The purposes of this study are to examine the correlation between the activation of these pathways and clinicopathologic or prognostic factors and to identify candidate target molecules in MPNST. Moreover, we assessed the antitumor effects of the inhibitor of candidate target.

EXPERIMENTAL DESIGN

Immunohistochemistry was conducted to evaluate the activation profiles of AKT/mTOR and MAPK pathways using 135 tumor specimens. Immunohistochemical expressions were confirmed by Western blotting. Then, an in vitro study was conducted to examine the antitumor effect of the mTOR inhibitor on MPNST cell lines.

RESULTS

Phosphorylated-AKT (p-AKT), p-mTOR, p-S6RP, p-p70S6K, p-4E-BP1, p-MEK1/2, and p-ERK1/2 expressions were positive in 58.2%, 47.3%, 53.8%, 57.1%, 62.6%, 93.4%, and 81.3% of primary MPNSTs, respectively. Positivity for each factor showed no difference between NF1-related and sporadic MPNSTs. Univariate prognostic analysis revealed that p-AKT, p-mTOR, and p-S6RP expressions were associated with poor prognosis. Furthermore, activation of each p-mTOR and p-S6RP was an independent poor prognostic factor by multivariate analysis. mTOR inhibition by Everolimus showed antitumor activity on MPNST cell lines in vitro.

CONCLUSION

mTOR inhibition is a potential treatment option for both NF1-related and sporadic MPNSTs.

Macrophage infiltration predicts a poor prognosis for human ewing sarcoma

Ewing sarcoma-primitive neuroectodermal tumor (EWS) is associated with the most unfavorable prognosis of all primary musculoskeletal tumors. The objective of the present study was to investigate whether tumor-associated macrophages (TAMs) affect the development of EWS. TAMs were isolated from mouse xenografts using CD11b magnetic beads and examined for their cytokine expression and osteoclastic differentiation. To evaluate the role of TAMs in xenograft formation, liposome-encapsulated clodronate was used to deplete TAMs in mice. Macrophage infiltration and tumor microvascular density were histologically evaluated in 41 patients with EWS, and association with prognosis was examined using Kaplan-Meier survival analysis. In mouse EWS xenografts, TAMs expressed higher concentrations of cytokines including interleukin-6, keratinocyte-derived chemokine, and monocyte chemotactic protein-1. TAMs were more capable than normal monocytes of differentiating into tartrate-resistant acid phosphatase-positive giant cells. Depleting macrophages using liposome-encapsulated clodronate significantly inhibited development of EWS xenografts. In human EWS samples, higher levels of CD68-positive macrophages were associated with poorer overall survival. In addition, enhanced vascularity, increase in the amount of C-reactive protein, and higher white blood cell counts were also associated with poor prognosis and macrophage infiltration. TAMs seem to enhance the progression of EWS by stimulating both angiogenesis and osteoclastogenesis. Further investigation of the behavior of TAMs may lead to development of biologically targeted therapies for EWS.

Role of the VEGF-Flt-1-FAK pathway in the pathogenesis of osteoclastic bone destruction of giant cell tumors of bone

Background

Giant cell tumors (GCTs) of bone are primary benign bone tumors that are characterized by a high number of osteoclast-like multinuclear giant cells (MNCs). Recent studies suggest that the spindle-shaped stromal cells in GCTs are tumor cells, while monocyte-like cells and MNCs are reactive osteoclast precursor cells (OPCs) and osteoclasts (OCs), respectively. In this study, we investigated the pathogenesis of osteoclastic bone destruction in GCTs by focusing on the role of the vascular endothelial growth factor (VEGF)-Flt-1 (type-1 VEGF receptor)-focal adhesion kinase (FAK) pathway.

Methods

The motility of OPCs cells was assessed by a chemotaxis assay and the growth of OPCs was examined using a cell proliferation assay. The expression of VEGF and activation of Flt-1 and FAK in clinical GCT samples and in OPCs were detected by immunohistochemistry and immunoblotting. The correlation between the expression levels of activated Flt-1 and FAK and clinical stages of GCTs was investigated by immunohistochemistry.

Results

In GCT samples, CD68, a marker of OPCs and OCs, co-localized with Flt-1. Conditioned media from GCT tissue (GCT-CM) enhanced the chemotaxis and proliferation of OPCs. GCT-CM also stimulated FAK activation in OPCs in vitro. Moreover, there was a correlation between the clinical stage of GCTs and the expression of tyrosine-phosphorylated Flt-1 and FAK.

Conclusions

Our results suggest that the VEGF-Flt-1-FAK pathway is involved in the pathogenesis of bone destruction of GCTs.

Delayed onset of systemic bacterial dissemination and subsequent death in mice injected intramuscularly with Streptococcus pyogenes strains

Streptococcus pyogenes causes severe invasive diseases in humans, including necrotizing fasciitis, sepsis, and streptococcal toxic shock syndrome (STSS). We found that mice infected intramuscularly (i.m.) with S. pyogenes strains developed bacteremia and subsequent sudden death after at least 10 days of a convalescent period. Mostly, it occurred more than 21 days after muscle infection. We provisionally designate this phenomenon as "delayed death." Just after muscle infection, all the mice lost weight and activity, but recovered completely within 3 days. They had kept good activity and a fine coat of fur till one or two days before their death. Some of the dead mice were found to have soft-tissue necrosis. There was no correlation between the virulence leading to the delayed death and the severity of diseases from which strains were isolated. It was also found that the production of neither streptococcal pyrogenic exotoxin (SPE) A nor B correlated to the virulence leading to delayed death. The bacteria obtained from the organs of the mice with delayed death expressed capsule. We suggest that the mice with delayed onset of systemic bacterial dissemination and subsequent death after muscle infection with S. pyogenes are the animal models of STSS, because the pathophysiology is extremely similar to that of human STSS.

Distinct distribution of protein disulfide isomerase family proteins in rat tissues

We investigated the distribution of protein disulfide isomerase (PDI) family proteins PDI, ERp72, and ERp61 in rat tissues and compared their localization by immunohistochemical double staining. The extent of their expression was diverse in different cell types, although they were ubiquitously distributed in a wide variety of cell types. Prominent staining for all three proteins was detected in thyroid follicular epithelia, tracheal mucous gland cells and chondrocytes, and chief cells and mucous neck cells of the stomach. Hepatocytes, neuronal cells in brain and spinal cord, and pancreatic acinar cells were also consistently and uniformly stained, but with low intensity. On the other hand, distinct differences were observed for the expression of the three proteins in plasma cells, pancreatic islet cells, goblet cells, and Paneth's cells of intestines, seminiferous epithelia, and salivary gland ductal epithelia. The similarities and differences in the distribution of the three proteins provide helpful clues to their biological functions.