Significant Genes Associated with Mortality and Disease Progression in Grade II and III Glioma

BACKGROUND

The Wnt/β-catenin pathway plays a critical role in the tumorigenesis and maintenance of glioma stem cells. This study aimed to evaluate significant genes associated with the Wnt/β-catenin pathway involved in mortality and disease progression in patients with grade II and III glioma, using the Cancer Genome Atlas (TCGA) database.

METHODS

We obtained clinicopathological information and mRNA expression data from 515 patients with grade II and III gliomas from the TCGA database. We performed a multivariate Cox regression analysis to identify genes independently associated with glioma prognosis.

RESULTS

The analysis of 34 genes involved in Wnt/β-catenin signaling demonstrated that four genes (CER1, FRAT1, FSTL1, and RPSA) related to the Wnt/β-catenin pathway were significantly associated with mortality and disease progression in patients with grade II and III glioma. We also identified additional genes related to the four significant genes of the Wnt/β-catenin pathway mentioned above. The higher expression of BMP2, RPL18A, RPL19, and RPS12 is associated with better outcomes in patients with glioma.

CONCLUSIONS

Using a large-scale open database, we identified significant genes related to the Wnt/β-catenin signaling pathway associated with mortality and disease progression in patients with grade II and III gliomas.

The genes significantly associated with an improved prognosis and long-term survival of glioblastoma

BACKGROUND AND PURPOSE

Glioblastoma multiforme (GBM) is the most devastating brain tumor with less than 5% of patients surviving 5 years following diagnosis. Many studies have focused on the genetics of GBM with the aim of improving the prognosis of GBM patients. We investigated specific genes whose expressions are significantly related to both the length of the overall survival and the progression-free survival in patients with GBM.

METHODS

We obtained data for 12,042 gene mRNA expressions in 525 GBM tissues from the Cancer Genome Atlas (TCGA) database. Among those genes, we identified independent genes significantly associated with the prognosis of GBM. Receiver operating characteristic (ROC) curve analysis was performed to determine the genes significant for predicting the long-term survival of patients with GBM. Bioinformatics analysis was also performed for the significant genes.

RESULTS

We identified 33 independent genes whose expressions were significantly associated with the prognosis of 525 patients with GBM. Among them, the expressions of five genes were independently associated with an improved prognosis of GBM, and the expressions of 28 genes were independently related to a poorer prognosis of GBM. The expressions of the ADAM22, ATP5C1, RAC3, SHANK1, AEBP1, C1RL, CHL1, CHST2, EFEMP2, and PGCP genes were either positively or negatively related to the long-term survival of GBM patients.

CONCLUSIONS

Using a large-scale and open database, we found genes significantly associated with both the prognosis and long-term survival of patients with GBM. We believe that our findings may contribute to improving the understanding of the mechanisms underlying GBM.

Risk Factors for Prevertebral Soft Tissue Swelling Following Single-Level Anterior Cervical Spine Surgery

OBJECTIVE

Anterior cervical spine surgery (ACSS) is a common surgical procedure used to treat cervical spinal degenerative diseases. One of the complications associated with ACSS is prevertebral soft tissue swelling (PSTS), which can result in airway obstruction, dysphagia, and other adverse outcomes. This study aims to investigate the correlation between various cervical sagittal parameters and PSTS following single-level ACSS, as well as to identify independent risk factors for PSTS.

METHODS

A retrospective study conducted at a single institution. The study population included all patients who underwent single-level ACSS between January 2014 and December 2022. Patients with a history of cervical spine surgery or trauma were excluded from the study. The presence and severity of PSTS was assessed by reviewing pre- and postoperative imaging studies. The potential risk factors for PSTS that were examined include patient age, sex, body mass index, tobacco use, comorbidities, serum albumin levels, operative time, implant type, implanted level, and various cervical spine sagittal parameters. Multivariate linear regression analysis was performed to identify the independent risk factors for PSTS.

RESULTS

A total of 62 consecutive patients who underwent single-level ACSS over a 8-year period at a single institution were enrolled in this study. Only preoperative segmental angle showed positive correlation with PSTS among various cervical spine sagittal parameters (r=0.36, p=0.005). Artificial disc replacement showed a negative correlation with PSTS (β=-0.38, p=0.002), whereas the use of demineralized bone matrix (DBM) had a positive impact on PSTS (β=0.33, p=0.009). We found that male sex, lower preoperative serum albumin, and implantation of upper cervical level (above C5) were independent predictors for PSTS after single-level ACSS (β=1.21; 95% confidence interval [CI], 0.27 to 2.15; p=0.012; β=-1.63; 95% CI, -2.91 to -0.34; p=0.014; β=1.44; 95% CI, 0.38 to 2.49; p=0.008, respectively).

CONCLUSION

Our study identified male sex, lower preoperative serum albumin levels, and upper cervical level involvement as independent risk factors for PSTS after single-level ACSS. These findings can help clinicians monitor high-risk patients and take preventive measures to reduce complications. Further research with larger sample sizes and prospective designs is needed to validate these findings.

DKK3 expression is associated with immunosuppression and poor prognosis in glioblastoma, in contrast to lower-grade gliomas

PURPOSE

We previously reported that expression of dickkopf-3 (DKK3), which is involved in the Wnt/β-catenin pathway, is significantly associated with prognosis in patients with glioblastoma multiforme (GBM). The aim of this study was to compare the association of DKK3 with other Wnt/β-catenin pathway-related genes and immune responses between lower grade glioma (LGG) and GBM.

METHODS

We obtained the clinicopathological data of 515 patients with LGG (World Health Organization [WHO] grade II and III glioma) and 525 patients with GBM from the Cancer Genome Atlas (TCGA) database. We performed Pearson's correlation analysis to investigate the relationships between Wnt/β-catenin-related gene expression in LGG and GBM. Linear regression analysis was performed to identify the association between DKK3 expression and immune cell fractions in all grade II to IV gliomas.

RESULTS

A total of 1,040 patients with WHO grade II to IV gliomas were included in the study. As the grade of glioma increased, DKK3 showed a tendency to be more strongly positively correlated with the expression of other Wnt/β-catenin pathway-related genes. DKK3 was not associated with immunosuppression in LGG but was associated with downregulation of immune responses in GBM. We hypothesized that the role of DKK3 in the Wnt/β-catenin pathway might be different between LGG and GBM.

CONCLUSION

According to our findings, DKK3 expression had a weak effect on LGG but a significant effect on immunosuppression and poor prognosis in GBM. Therefore, DKK3 expression seems to play different roles, through the Wnt/β-catenin pathway, between LGG and GBM.

Identification of genes from ten oncogenic pathways associated with mortality and disease progression in glioblastoma

Glioblastoma multiforme (GBM) is the most malignant brain tumor with an extremely poor prognosis. The Cancer Genome Atlas (TCGA) database has been used to confirm the roles played by 10 canonical oncogenic signaling pathways in various cancers. The purpose of this study was to evaluate the expression of genes in these 10 canonical oncogenic signaling pathways, which are significantly related to mortality and disease progression in GBM patients. Clinicopathological information and mRNA expression data of 525 patients with GBM were obtained from TCGA database. Gene sets related to the 10 oncogenic signaling pathways were investigated via Gene Set Enrichment Analysis. Multivariate Cox regression analysis was performed for all the genes significantly associated with mortality and disease progression for each oncogenic signaling pathway in GBM patients. We found 12 independent genes from the 10 oncogenic signaling pathways that were significantly related to mortality and disease progression in GBM patients. Considering the roles of these 12 significant genes in cancer, we suggest possible mechanisms affecting the prognosis of GBM. We also observed that the expression of 6 of the genes significantly associated with a poor prognosis of GBM, showed negative correlations with CD8+ T-cells in GBM tissue. Using a large-scale open database, we identified 12 genes belonging to 10 well-known oncogenic canonical pathways, which were significantly associated with mortality and disease progression in patients with GBM. We believe that our findings will contribute to a better understanding of the mechanisms underlying the pathophysiology of GBM in the future.

Efficacy of Cytokine-Induced Killer Cell Immunotherapy for Patients With Pathologically Pure Glioblastoma

The most common malignant central nervous system tumor is glioblastoma multiforme (GBM). Cytokine-induced killer (CIK) cell therapy is a promising type of adoptive cell immunotherapy for various cancers. We previously conducted a randomized clinical trial on CIK cell therapy in patients with GBM. The aim of this study was to evaluate the efficacy of CIK immunotherapy for patients with pathologically pure GBM, using data from our previous randomized clinical trial. The difference between overall survival (OS) and progression-free survival (PFS) according to CIK immunotherapy was analyzed using the Kaplan–Meier method. Hazard ratios were calculated using univariate and multivariate Cox regression analyses to determine whether CIK cell immunotherapy was independently associated with higher OS and PFS in patients with pure GBM. A total of 156 eligible patients were included in the modified intention-to-treat (mITT) population. We confirmed that 125 (80.1%) GBM samples were pure GBM tumors without the presence of other types of tumors. For patients with pure GBM, Kaplan-Meier analysis showed no significant difference in OS between the CIK cell treatment and control groups. However, multivariate Cox regression demonstrated CIK cell immunotherapy as an independent predictor of greater OS (hazard ratio, 0.59; 95% CI, 0.36–0.97; p = 0.038) and PFS (hazard ratio, 0.55; 95% CI, 0.36–0.84; p = 0.001) in patients with pathologically pure GBM in the mITT population. This study showed that CIK cell immunotherapy combined with conventional temozolomide chemoradiotherapy could prolong OS and PFS in patients with newly diagnosed pathologically pure GBM, with no significant adverse events related to treatment. However, unlike the results of multivariate Cox analysis, no statistical significance of CIK cell immunotherapy in OS in Kaplan-Meier analysis raises a question. Further studies are required to validate these results.

Effect of osteoporotic conditions on the development of peritumoral brain edema after LINAC-based radiation treatment in patients with intracranial meningioma

PURPOSE

Disruption of the tumor-brain barrier in meningioma is a crucial factor in peritumoral brain edema (PTBE). We previously reported the possible effect of osteoporosis on the integrity of the arachnoid trabeculae because both the bone and the arachnoid trabeculae are composed of type 1 collagen. We hypothesized that osteoporotic conditions may be associated with PTBE occurrence after radiation treatment in patients with meningioma.

METHODS

A receiver operating characteristic curve analysis was used to identify the optimal cut-off values of mean skull Hounsfield unit for predicting osteopenia and osteoporosis in patients from our registry. Multivariate Cox regression analysis was used to determine whether possible osteoporosis independently predicted PTBE development in patients with meningioma after radiation.

RESULTS

A total of 106 intracranial meningiomas were included for the study. All patients received linear accelerator-based radiation therapy in our hospital over an approximate 6-year period. Multivariate Cox regression analysis identified that hypothetical osteoporosis was an independent predictive factor for the development of PTBE in patients with meningioma after linear accelerator-based radiation treatment (hazard ratio 5.20; 95% confidence interval 1.11-24.46; p = 0.037).

CONCLUSIONS

Our study suggests that possible osteoporotic conditions may affect PTBE development after linear accelerator-based radiation treatment for intracranial meningioma. However, due to the study's small number of patients, these findings need to be validated in future studies with larger cohorts, before firm recommendations can be made.

Effect of Osteoporotic Condition on Ventriculomegaly and Shunt-Dependent Hydrocephalus After Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Hydrocephalus is a common complication in aneurysmal rupture subarachnoid hemorrhage (SAH). As both the bone and arachnoid trabeculae are composed of type 1 collagen, we identified the possible relationship between bone mineral density and ventriculomegaly and shunt-dependent hydrocephalus (SDHC) development after aneurysmal rupture SAH in younger patients.

METHODS

We measured frontal skull Hounsfield unit (HU) values on brain computed tomography upon admission, and mean frontal skull HU values were used instead of T-score value. Hazard ratios were calculated using Cox regression analysis to identify whether osteoporotic condition is an independent predictor for ventriculomegaly and SDHC after surgical clipping for SAH in younger patients.

RESULTS

Altogether, 412 patients (≤65 years) who underwent surgical clipping for primary spontaneous SAH from a ruptured aneurysm were enrolled in this 11-year analysis in 2 hospitals. We observed that the first tertile group of skull HU was an independent predictor of SDHC after SAH compared with the third tertile of skull HU values (hazard ratio, 2.55 [95% CI, 1.25-5.20]; P=0.010). There were no significant interactions between age and skull HU with respect to ventriculomegaly and SDHC in younger patients.

CONCLUSIONS

Our study suggests a relationship between possible osteoporotic conditions and ventriculomegaly and SDHC development after SAH in younger patients. Our findings may be useful in predicting hydrocephalus in young SAH patients using a convenient method of measuring skull HU value on brain computed tomography upon admission.

Biomechanical analysis of a newly developed interspinous process device conjunction with interbody cage based on a finite element model

Purpose

This study aimed to investigate the biomechanical effects of a newly developed interspinous process device (IPD), called TAU. This device was compared with another IPD (SPIRE) and the pedicle screw fixation (PSF) technique at the surgical and adjacent levels of the lumbar spine.

Materials and methods

A three-dimensional finite element model analysis of the L1-S1 segments was performed to assess the biomechanical effects of the proposed IPD combined with an interbody cage. Three surgical models—two IPD models (TAU and SPIRE) and one PSF model—were developed. The biomechanical effects, such as range of motion (ROM), intradiscal pressure (IDP), disc stress, and facet loads during extension were analyzed at surgical (L3-L4) and adjacent levels (L2-L3 and L4-L5). The study analyzed biomechanical parameters assuming that the implants were perfectly fused with the lumbar spine.

Results

The TAU model resulted in a 45%, 49%, 65%, and 51% decrease in the ROM at the surgical level in flexion, extension, lateral bending, and axial rotation, respectively, when compared to the intact model. Compared to the SPIRE model, TAU demonstrated advantages in stabilizing the surgical level, in all directions. In addition, the TAU model increased IDP at the L2-L3 and L4-L5 levels by 118.0% and 78.5% in flexion, 92.6% and 65.5% in extension, 84.4% and 82.3% in lateral bending, and 125.8% and 218.8% in axial rotation, respectively. Further, the TAU model exhibited less compensation at adjacent levels than the PSF model in terms of ROM, IDP, disc stress, and facet loads, which may lower the incidence of the adjacent segment disease (ASD).

Conclusion

The TAU model demonstrated more stabilization at the surgical level than SPIRE but less stabilization than the PSF model. Further, the TAU model demonstrated less compensation at adjacent levels than the PSF model, which may lower the incidence of ASD in the long term. The TAU device can be used as an alternative system for treating degenerative lumbar disease while maintaining the physiological properties of the lumbar spine and minimizing the degeneration of adjacent segments.

Relationship between the atlantodental interval and T1 slope after atlantoaxial fusion in patients with rheumatoid arthritis

BACKGROUND

Atlantoaxial fusion has been widely used for the treatment of atlantoaxial instability (AAI). However, atlantoaxial fusion sacrifices the motion of atlantoaxial articulation, and postoperative loss of cervical lordosis and aggravation of cervical kyphosis are observed. We investigated various factors under the hypothesis that the atlantodental interval (ADI) and T1 slope may be associated with sagittal alignment after atlantoaxial fusion in patients with rheumatoid arthritis (RA).

METHODS

We retrospectively investigated 64 patients with RA who underwent atlantoaxial fusion due to AAI. Radiological factors, including the ADI, T1 slope, Oc-C2 angle, cervical sagittal vertical axis, and C2-C7 angle, were measured before and after surgery.

RESULTS

The various factors associated with atlantoaxial fusion before and after surgery were compared according to the upper and lower preoperative ADIs. There was a significant difference in the T1 slope 1 year after surgery (p = 0.044) among the patients with lower preoperative ADI values. The multivariate logistic regression analysis showed that the preoperative ADI (> 7.92 mm) defined in the receiver-operating characteristic curve analysis was an independent predictive factor for the increase in the T1 slope 1 year after atlantoaxial fusion (odds ratio, 4.59; 95% confidence interval, 1.34-15.73; p = 0.015).

CONCLUSION

We found an association between the preoperative ADI and difference in the T1 slope after atlantoaxial fusion in the patients with RA. A preoperative ADI (> 7.92 mm) was an independent predictor for the increase in the T1 slope after atlantoaxial fusion. Therefore, performing surgical treatment when the ADI is low would lead to better cervical sagittal alignment.

Effects of Possible Osteoporotic Conditions on the Recurrence of Chronic Subdural Hematoma

The recurrence rate of chronic subdural hematoma (CSDH) has been reported to range from 2.3 to 33%. As bridging veins are composed of abundant collagen bundles and bone matrix, we aimed to investigate the possible associations between skull Hounsfield unit (HU) values and the recurrence of CSDH. We retrospectively enrolled patients with CSDH who underwent burr hole surgery. The HU values of the frontal skull were measured on brain CT scans. The cumulative hazard for recurrence was estimated according to predictive factors. To identify the independent predictors associated with the recurrence of CSDH, hazard ratios (HRs) were estimated using multivariate Cox regression analysis. A total of 208 consecutive patients who underwent burr hole trephination for CSDH over a 7-years period at a single institution were enrolled in this study. We found that age, greater midline shift (≥10.5 mm), lower skull HU (<769.5), and diabetes were independent predictors for the recurrence of CSDH (HR 1.06, 95% confidence interval [CI] 1.00–1.12, p = 0.042; HR 5.37, 95% CI 1.48–19.46, p = 0.010; HR 6.71, 95% CI 1.84–24.45, p = 0.004; and HR 3.30, 95% CI 1.05–10.43, p = 0.042, respectively). A relationship between possible low bone mineral density (BMD) and CSDH recurrence was observed. In addition, age, greater preoperative midline shift, and diabetes were also identified as predictive factors for recurrence. We expect that our findings may facilitate our understanding of the possible association between CSDH and BMD.

Does the skull Hounsfield unit predict shunt dependent hydrocephalus after decompressive craniectomy for traumatic acute subdural hematoma?

Background and purpose

Posttraumatic hydrocephalus affects 11.9%–36% of patients undergoing decompressive craniectomy (DC) after traumatic brain injury and necessitates a ventriculo-peritoneal shunt placement. As bone and arachnoid trabeculae share the same collagen type, we investigated possible connections between the skull Hounsfield unit (HU) values and shunt-dependent hydrocephalus (SDHC) in patients that received cranioplasty after DC for traumatic acute subdural hematoma (SDH).

Methods

We measured HU values in the frontal bone and internal occipital protuberance from admission brain CT. Receiver operating characteristic curve analysis was performed to identify the optimal cut-off skull HU values for predicting SDHC in patients receiving cranioplasty after DC due to traumatic acute SDH. We investigated independent predictive factors for SDHC occurrence using multivariable logistic regression analysis.

Results

A total of 162 patients (>15 years of age) were enrolled in the study over an 11-year period from two university hospitals. Multivariable logistic analysis revealed that the group with simultaneous frontal skull HU ≤797.4 and internal occipital protuberance HU ≤586.5 (odds ratio, 8.57; 95% CI, 3.05 to 24.10; P<0.001) was the only independent predictive factor for SDHC in patients who received cranioplasty after DC for traumatic acute SDH.

Conclusions

Our study reveals a potential relationship between possible low bone mineral density and development of SDHC in traumatic acute SDH patients who had undergone DC. Our findings provide deeper insight into the association between low bone mineral density and hydrocephalus after DC for traumatic acute SDH.

Significance of skull osteoporosis to the development of peritumoral brain edema after LINAC-based radiation treatment in patients with intracranial meningioma

Background and purpose

Disruption of the tumor-brain barrier in meningioma plays a critical role in the development of peritumoral brain edema (PTBE). We hypothesized that osteoporotic conditions may be associated with PTBE occurrence after radiation in patients with intracranial meningioma.

Methods

We measured Hounsfield units (HU) of the frontal skull on simulation brain CT in patients who underwent linear accelerator (LINAC)-based radiation treatment for intracranial meningioma. Receiver operating characteristic curve analysis was performed to determine the optimal cut-off values for several predictive factors. The cumulative hazard for PTBE was estimated and classified according to these factors. Hazard ratios were then estimated to identify independent predictive factors associated with the development of PTBE after radiation in intracranial meningioma patients.

Results

A total of 83 intracranial meningiomas in 76 patients who received LINAC-based radiation treatment in our hospital over an approximate 5-year period were included for the study. We found mean frontal skull HU ≤630.625 and gross tumor volume >7.194 cc to be independent predictors of PTBE after radiation treatment in patients with meningioma (hazard ratio, 8.41; P = 0.019; hazard ratio, 5.92; P = 0.032, respectively). In addition, patients who were ≥65 years showed a marginally significant association with PTBE.

Conclusions

Our study suggests that possible osteoporotic conditions, large tumor volume, and older age may be associated with PTBE occurrence after LINAC-based radiation treatment for intracranial meningioma. In the future we anticipate that these findings may enhance the understanding of the underlying mechanisms of PTBE after radiation in meningioma patients.

Association between cerebral atrophy and osteoporotic vertebral compression fractures

PURPOSE

Osteoporotic vertebral compression fractures (OVCFs) have a serious impact on people's health and quality of life. The purpose of this study was to analyze brain volume in patients with osteoporosis using brain magnetic resonance imaging (MRI) and to investigate the relationship with osteoporotic vertebral compression fractures.

MATERIALS AND METHODS

We included 246 patients with osteoporosis who underwent thoracolumbar radiographs and brain MRI at our hospital. Clinical data on age, sex, bone mineral density, height, weight, osteoporosis medication, hypertension, diabetes, alcohol drinking, and smoking were collected. Intracranial cavity, brain parenchyma, and lateral ventricles volumes were measured using brain MRI with a semiautomated tool.

RESULTS

We founded an independent correlation between age and volume percentages of the brain parenchyma and lateral ventricles. We observed a statistically significant decrease in volume percentage of the brain parenchyma and an increase in volume percentage of the lateral ventricles with increasing age. In addition, we confirmed that patients with OVCF showed a significantly lower volume percentage of brain parenchyma than patients without OVCF.

CONCLUSION

We observed a significant association between OVCF and volume percentage of brain parenchyma. Degeneration of the brain may lead to a high incidence of falls, and OVCF may occur more frequently in patients with osteoporosis.

LGR5 and Downstream Intracellular Signaling Proteins Play Critical Roles in the Cell Proliferation of Neuroblastoma, Meningioma and Pituitary Adenoma

Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) has been reported to play critical roles in the proliferation of various cancer cells. However, the roles of LGR5 in brain tumors and the specific intracellular signaling proteins directly associated with it remain unknown. Expression of LGR5 was first measured in normal brain tissue, meningioma, and pituitary adenoma of humans. To identify the downstream signaling pathways of LGR5, siRNA-mediated knockdown of LGR5 was performed in SH-SY5Y neuroblastoma cells followed by proteomics analysis with 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In addition, the expression of LGR5-associated proteins was evaluated in LGR5-inhibited neuroblastoma cells and in human normal brain, meningioma, and pituitary adenoma tissue. Proteomics analysis showed 12 protein spots were significantly different in expression level (more than two-fold change) and subsequently identified by peptide mass fingerprinting. A protein association network was constructed from the 12 identified proteins altered by LGR5 knockdown. Direct and indirect interactions were identified among the 12 proteins. HSP 90-beta was one of the proteins whose expression was altered by LGR5 knockdown. Likewise, we observed decreased expression of proteins in the hnRNP subfamily following LGR5 knockdown. In addition, we have for the first time identified significantly higher hnRNP family expression in meningioma and pituitary adenoma compared to normal brain tissue. Taken together, LGR5 and its downstream signaling play critical roles in neuroblastoma and brain tumors such as meningioma and pituitary adenoma.

Association between bone mineral density and brain parenchymal atrophy and ventricular enlargement in healthy individuals

Bone, vascular smooth muscle, and arachnoid trabeculae are composed of the same type of collagen. However, no studies have investigated the relationship between bone mineral density deterioration and cerebral atrophy, both of which occur in normal, healthy aging. Accordingly, we evaluated whether bone mineral density was associated with brain parenchymal atrophy and ventricular enlargement in healthy individuals. Intracranial cavity, brain parenchyma, and lateral ventricles volumes were measured using brain magnetic resonance imaging (MRI) with a semiautomated tool. We included 267 individuals with no history of dementia or other neurological diseases, who underwent one or more dual-energy X-ray absorptiometry scans and brain MRIs simultaneously (within 3 years of each other) at our hospital over an 11-year period. We found that progression of brain parenchymal atrophy was positively associated with bone mineral density after full adjustment (B, 0.94; P < 0.001). In addition, individuals with osteoporosis showed more parenchymal atrophy among those younger than 80 years. In addition, we observed greater ventricular enlargement in individuals with osteoporosis among those older than 80 years. We believe that osteoporosis may play a role in the acceleration of parenchymal atrophy during the early-stages, and ventricular enlargement in the late-stages, of normal aging-related cerebral atrophy.

Association Between Possible Osteoporosis and Shunt-Dependent Hydrocephalus After Subarachnoid Hemorrhage

Background and Purpose- Pathological obstruction in arachnoid granulations after subarachnoid hemorrhage (SAH) can impede cerebrospinal fluid flow outward to the venous sinus and causing hydrocephalus. Because bone and arachnoid granulations share the same collagen type, we evaluated the possible relation between bone mineral density and shunt-dependent hydrocephalus after SAH. Methods- We measured Hounsfield units of the frontal skull on admission brain computed tomography in patients with SAH. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff Hounsfield unit in skull to predict osteopenia and osteoporosis in a large sample registry. According to the optimal cutoff skull Hounsfield unit values, study patients were then categorized as hypothetical normal, osteopenia, and osteoporosis. Odds ratios were estimated using logistic regression to determine whether the osteoporotic conditions are independent predictive factors for the development of shunt-dependent hydrocephalus after clipping for SAH. Results- A total of 447 patients (alive ≥14 days) with ruptured aneurysm SAH who underwent surgical clipping were retrospectively enrolled in this study during a 9-year period from 2 hospitals. We found that hypothetical osteoporosis was an independent predictor for shunt-dependent hydrocephalus after aneurysmal clipping for SAH after full adjustment for other predictive factors, including age (odds ratio, 2.08; 95% confidence interval, 1.06-4.08; P=0.032). Conclusions- Our study demonstrates a possible relation between possible osteoporosis and hydrocephalus after SAH. Hounsfield unit measurement on admission brain computed tomography may be helpful for predicting hydrocephalus during the clinical course of SAH in patients with osteoporosis or suspected osteoporosis.

Upper Cervical Subluxation and Cervicomedullary Junction Compression in Patients with Rheumatoid Arthritis

Objective

Rheumatoid arthritis (RA) is known to involve the cervical spine up to 86%. It often causes cervical instability like atlantoaxial subluxation (AAS), subaxial subluxation, and vertical subluxation (VS). In order to find the relation between RA and cord compression, we will evaluate the characteristics and risk factors of basilar invagination (BI) and cervicomedullary junction (CMJ) compression.

Methods

From January 2007 to May 2015, 12667 patients administrated to Hanyang University Medical Center. Four thousand three hundred eighty-six patients took cervical X-ray and 250 patients took cervical computed tomography or magnetic resonance imaging. Radiologic parameters, medication records were obtained from 242 patients. Multivariate logistic regression analysis was performed with correlation of CMJ compression, basin-dental interval (BDI), basin-posterior axial line interval (BAI), pannus formation, BI, and AAS.

Results

In the point of CMJ compression, atlantodental interval (ADI), posterior-atlantodental interval, BAI, AAS, and BI are relatively highly correlated. Patients with BI have 82 times strong possibility of radiologic confirmed CMJ compression, while AAS has 6-fold and pannus formation has the 3-fold possibility. Compared to the low incidence of BI, AAS and pannus formation have more proportion in CMJ compression. Furthermore, wrist joint erosion was correlated with VS and AAS.

Conclusion

BI has a very strong possibility of CMJ compression, while AAS and pannus formation have a high proportion in CMJ compression. Hence bilateral wrist joint erosion can be used as an indicator for the timing of screening test for cervical involvement. We suggest the early recommendation of cervical spine examination for the diagnosis of cervical involvement in order to prevent morbidity and mortality.

Paradoxical relationship between body mass index and bone mineral density in patients with non-small cell lung cancer with brain metastasis

Background and purpose

Low body mass index (BMI) at presentation has been reported to be associated with higher incidence and mortality of lung cancer, but studies on the relationship between brain metastasis and BMI at presentation are lacking. This study aimed to evaluate the association between brain metastasis and BMI and bone mineral density (BMD) in NSCLC.

Methods

We retrospectively enrolled patients with non–small cell lung cancer who underwent brain magnetic resonance imaging with contrast within 3 months of diagnosis. The BMI was collected, and the BMD was measured in Hounsfield unit (HU) on initial staging computed tomography scans. The independent relationship between BMI and BMD was assessed using multivariable linear regression according to the presence of brain metastasis.

Results

A total of 356 consecutive NSCLC patients were enrolled in the study over a 8-year period in a single institution. Lower BMI with higher BMD was an independent predictive factor for brain metastasis in patients with NSCLC, relative to the other group (HR, 2.03; 95% CI, 1.21 to 3.40; P = 0.007). We also found a significant negative correlation between BMI and BMD among patients with NSCLC with brain metastases (B, -3.343; 95% confidence interval, -6.352 to -0.333; P = 0.030).

Conclusions

Brain metastasis may possibly be associated with lower BMI and higher BMD in NSCLC patients. We expect that these results may facilitate future predictions of brain metastases during the clinical course of NSCLC and enhance our understanding of the underlying mechanisms that link brain metastases and lung cancer.

Postpartum Superior Sagittal Sinus Thrombosis: A Case Report

Cerebral venous sinus thrombosis (CVST) is a rare disease. Early diagnosis and treatment are important, as CVST is potentially fatal. Pregnancy and puerperium are known risk factors for CVST. Here, we report the case of a patient who developed superior sagittal sinus thrombosis after a normal vaginal delivery. A 20-year-old woman presented with a headache and seizures two days after a normal vaginal delivery. Initially, brain computed tomography (CT) showed a subarachnoid hemorrhage in the right parietal lobe and sylvian fissure, together with mild cerebral edema. CT angiography revealed superior sagittal sinus thrombosis. Multiple micro-infarctions were seen on diffusion-weighted magnetic resonance images. An intravenous infusion of heparin and mannitol was administered immediately. Two days after treatment initiation, the patient showed sudden neurological deterioration, with left-sided hemiplegia. Brain CT showed moderate brain edema and hemorrhagic densities. Emergency decompressive craniectomy was performed, and heparin was re-administered on post-operative day (POD) 1. On POD 9, the patient's mental state improved from stupor to drowsy, but the left-sided hemiplegia persisted. CT angiography showed that the superior sinus thrombosis had decreased. Superior sagittal sinus thrombosis is an uncommon complication, with an unfavorable outcome, after delivery. Timely diagnosis and treatment are important for preventing neurological deterioration.

Opportunistic osteoporosis screening via the measurement of frontal skull Hounsfield units derived from brain computed tomography images

Background and purpose

Osteoporosis is one of the most common chronic metabolic diseases, but detection and treatment rates are low. The aim of the current study was to evaluate the correlation between frontal skull Hounsfield unit (HU) values from brain computed tomography (CT) scans and T-scores of the lumbar spine and femoral neck from dual-energy X-ray absorptiometry (DXA) scans.

Methods

Patients with < 1 year between brain CT and DXA scans were included in the study. The average frontal skull HU value used for analysis was defined as the average of four HU values of the frontal bone. A receiver operating characteristic curve was generated, and area under the curve (AUC) was used to determine the HU values of the frontal skull for predicting osteoporosis. The frontal skull HU value with the highest sensitivity and specificity was considered the optimal cutoff value.

Results

In total, 899 patients who underwent both brain CT and DXA scans at a single institution were enrolled. Average skull HU values differed significantly among patients in different bone mineral density categories (p < 0.001). There was a positive correlation between skull HU value and T-score (β = 105.06, p < 0.001, R² = 0.343). The mean HU value in subjects with osteoporosis was 515, and the optimal cutoff value for the prediction of osteoporosis was 610 HU (AUC = 0.775, 95% CI 0.744–0.806, p < 0.001).

Conclusions

Clinical brain CT scans can assist in the detection of osteoporosis, and patients with an HU value < 610 as determined via brain CT may be considered for further evaluation for possible osteoporosis.

Cervical Epidural Hematoma That Induced Sudden Paraparesis After Cervical Spine Massage: Case Report and Literature Review

BACKGROUND

Most people understand spinal manipulation therapy to be a safe procedure, and in many cases treatment is provided without a diagnosis if there is musculoskeletal pain. Cervical epidural hematoma occurs in extremely rare cases after cervical manipulation therapy. This study reports a case of epidural hematoma that occurred in the anterior spinal cord after cervical massage.

CASE DESCRIPTION

A 38-year-old male patient was admitted to the emergency department for sudden weakness in the lower extremity after receiving a cervical spine massage. No fracture was found using cervical radiographs, and there were no particular findings on performing brain computed tomography or diffusion magnetic resonance imaging. However, using cervical magnetic resonance imaging, an acute epidural hematoma was observed in the anterior spinal cord from the C6 and C7 vertebrae to the T1 vertebra, compressing the spinal cord. There were no fractures or ligament injury. No surgical treatment was required as the patient showed spontaneous improvements in muscle strength and was discharged after just 1 week, following observation of the improvement in his symptoms.

CONCLUSION

Although cervical epidural hematoma after cervical manipulation therapy is extremely rare, if suspected, a thorough examination must be performed in order to reduce the chances of serious neurologic sequelae.

Influence of systemic bone mineral density on atlantoaxial subluxation in patients with rheumatoid arthritis

Osteopenia and osteoporosis were independent predictive factors for higher atlantoaxial subluxation occurrence in patients with lower body mass index. Our findings suggest that patients with rheumatoid arthritis with osteopenia or osteoporosis, particularly those with lower body mass index (BMI), should be screened regularly to determine the status of their cervical spines.

INTRODUCTION

Cervical spine involvement in rheumatoid arthritis (RA) patients may cause serious adverse effects on quality of life and overall health. This study aimed to evaluate the association between atlantodental interval (ADI), atlantoaxial subluxation (AAS), and systemic bone mineral density (BMD) based on BMI variations among established patients with RA.

METHODS

The ADI was transformed to the natural log scale to normalize distributions for all analyses. Multivariable linear regression analyses were used to identify independent predictive factors for ADI based on each BMD classification. Multivariate Cox regression analyses were also performed to identify independent predictive factors for the risk of AAS, which were classified by tertile groups of BMI.

RESULTS

A total of 1220 patients with RA who had undergone at least one or more cervical radiography and BMD assessments were identified and enrolled. We found that the association between BMD and ADI (β, -0.029; 95% CI, -0.059 to 0.002; p = 0.070) fell short of achieving statistical significance. However, the ADI showed a 3.6% decrease per 1 BMI increase in the osteoporosis group (β, -0.036; 95% CI, -0.061 to -0.011; p = 0.004). The osteopenia and osteoporosis groups showed about a 1.5-fold and a 1.8-fold increased risk of AAS occurrence among the first tertile of the BMI group.

CONCLUSIONS

Our study showed a possible association between lower BMD and AAS occurrence in patients with RA with lower BMI. Further studies are needed to confirm our findings.

Current update of adoptive immunotherapy using cytokine-induced killer cells to eliminate malignant gliomas

The therapeutic outcome for those with malignant glioma is poor, even though diverse therapeutic modalities have been developed. Immunotherapy has emerged as a therapeutic approach for malignant gliomas, making it possible to selectively treat tumors while sparing normal tissue. Here, we review clinical trials of adoptive immunotherapy approaches for malignant gliomas. We also describe a clinical trial that examined the efficacy and safety of autologous cytokine-induced killer (CIK) cells along with concomitant chemoradiotherapy for newly diagnosed glioblastoma. These CIK cells identify and kill autologous tumor cells. This review focuses on the use of adoptive immunotherapy for malignant gliomas and reviews the current literature on the concept of antitumor activity mediated by CIK cells.

Radiologic Findings and Patient Factors Associated with 30-Day Mortality after Surgical Evacuation of Subdural Hematoma in Patients Less Than 65 Years Old

Objective

The purpose of this study is to evaluate the associations between 30-day mortality and various radiological and clinical factors in patients with traumatic acute subdural hematoma (SDH). During the 11-year study period, young patients who underwent surgery for SDH were followed for 30 days. Patients who died due to other medical comorbidities or other organ problems were not included in the study population.

Methods

From January 1, 2004 to December 31, 2014, 318 consecutive surgically-treated traumatic acute SDH patients were registered for the study. The Kaplan–Meier method was used to analyze 30-day survival rates. We also estimated the hazard ratios of various variables in order to identify the independent predictors of 30-day mortality.

Results

We observed a negative correlation between 30-day mortality and Glasgow coma scale score (per 1-point score increase) (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.52–0.70; p<0.001). In addition, use of antithrombotics (HR, 2.34; 95% CI, 1.27–4.33; p=0.008), history of diabetes mellitus (HR, 2.28; 95% CI, 1.20–4.32; p=0.015), and accompanying traumatic subarachnoid hemorrhage (hazard ratio, 2.13; 95% CI, 1.27–3.58; p=0.005) were positively associated with 30-day mortality.

Conclusion

We found significant associations between short-term mortality after surgery for traumatic acute SDH and lower Glasgow Coma Scale scores, use of antithrombotics, history of diabetes mellitus, and accompanying traumatic subarachnoid hemorrhage at admission. We expect these findings to be helpful for selecting patients for surgical treatment of traumatic acute SDH, and for making accurate prognoses.

Comparison of Transarticular Screw Fixation and C1 Lateral Mass-C2 Pedicle Screw Fixation in Patients with Rheumatoid Arthritis with Atlantoaxial Instability

BACKGROUND

Many surgical procedures have been introduced to manage atlantoaxial instability caused by rheumatoid arthritis (RA) to prevent complications and improve fusion rate. We report the surgical outcome between transarticular screw fixation (TAF) and C1 lateral mass-C2 pedicle screw fixation (C1LM-C2P) in patients with atlantoaxial instability from RA.

METHODS

Between 2002 and 2012, 58 patients were enrolled in the study. According to surgical procedures, patients were divided into 2 groups: group I who received TAF (n = 33) and group II who received C1LM-C2P (n = 25). Bony fusion was assessed by radiologic comparison immediately after the operation and 1 year postoperatively. In addition, complications and clinical and functional outcomes were evaluated.

RESULTS

Overall, bone fusion was achieved in 32 patients in group I (97%). In group II, the fusion rate was evaluated in 100% of patients. Complications (regardless of neurologic deterioration) were cable loosening and screw malposition in group I and violation into the vertebral canal and spinal canal in group II. There was no statistical significance in fusion rate, clinical outcomes, or complications. The 12-month atlantodental interval after operation for the C1LM-C2P group was significantly lower than that for the TAF group after adjusting for all variables.

CONCLUSIONS

Two surgical techniques showed a good fusion rate by rigid fixation in the immediate postoperative period and fewer surgery-related complications in patients with RA. Because surgical complications are more likely during the learning curve (as with other surgical techniques), surgeons should carefully evaluate patients before surgery by radiologic and neurologic examinations.

Predictive factors for recurrence and clinical outcomes in patients with chronic subdural hematoma

OBJECTIVE Chronic subdural hematoma (CSDH) is a common type of intracranial hemorrhage in elderly patients. Many studies have suggested various factors that may be associated with the recurrence of CSDH. However, the results are inconsistent. The purpose of this study was to determine the associations among patient factors, recurrence, and clinical outcomes of CSDH after bur hole surgery performed during an 11-year period at twin hospitals. METHODS Kaplan-Meier analysis was performed to evaluate the risk factors for CSDH recurrence. Univariate and multivariate Cox proportional hazards regression analyses were used to calculate hazard ratios with 95% CIs for CSDH recurrence based on many variables. One-way repeated-measures ANOVA was used to assess the differences in the mean modified Rankin Scale score between categories for each risk factor during each admission and at the last follow-up. RESULTS This study was a retrospective analysis of 756 consecutive patients with CSDH who underwent bur hole surgery at the Hanyang University Medical Center (Seoul and Guri) between January 1, 2004, and December 31, 2014. During the 6-month follow-up, 104 patients (13.8%) with recurrence after surgery for CSDH were identified. Independent risk factors for recurrence were as follows: age > 75 years (HR 1.72, 95% CI 1.03-2.88; p = 0.039), obesity (body mass index ≥ 25.0 kg/m²), and a bilateral operation. CONCLUSIONS This study determined the risk factors for recurrence of CSDH and their effects on outcomes. Further studies are needed to account for these observations and to determine their underlying mechanisms.

Multiple Meningocerebral Metastasis and Extensive Skull Metastasis from Squamous Cell Carcinoma of Esophagus: A Case Report and Review of Literature

Esophageal carcinoma rarely metastasizes to the brain. Although some studies have mentioned esophageal cancer with solitary brain metastasis or with meningocerebral metastasis or with skull metastasis, multiple meningocerebral metastasis and extensive skull metastasis from squamous cell carcinoma of esophagus has not been reported in the literature. We encountered a case of an extensive osteolytic change of the skull and multiple meningocerebral metastases from esophageal carcinoma.

Retrograde Stent-assisted Coil Embolization of Wide-neck or Branch-incorporated Posterior Communicating Artery Aneurysm

Endovascular coil embolization using a balloon- or stent-assisted technique for the treatment of wide-necked posterior communicating artery (PcomA) aneurysms is well established. However, complete aneurysm occlusion with preservation of the PcomA can be difficult in case of wide-neck aneurysms with a PcomA incorporation. We present two cases of stent-assisted coil embolization using a retrograde approach through the posterior circulation for wide-neck or branch-incorporated PcomA aneurysms. Retrograde stenting was successful without periprocedural complications. These aneurysms were completely occluded. The patency of the PcomA was maintained in all cases.

Risk Factors for the Development and Progression of Atlantoaxial Subluxation in Surgically Treated Rheumatoid Arthritis Patients, Considering the Time Interval between Rheumatoid Arthritis Diagnosis and Surgery

Objective

Rheumatoid arthritis (RA) is a systemic disease that can affect the cervical spine, especially the atlantoaxial region. The present study evaluated the risk factors for atlantoaxial subluxation (AAS) development and progression in patients who have undergone surgical treatment.

Methods

We retrospectively analyzed the data of 62 patients with RA and surgically treated AAS between 2002 and 2015. Additionally, we identified 62 patients as controls using propensity score matching of sex and age among 12667 RA patients from a rheumatology registry between 2007 and 2015. We extracted patient data, including sex, age at diagnosis, age at surgery, disease duration, radiographic hand joint changes, and history of methotrexate use, and laboratory data, including presence of rheumatoid factor and the C-reactive protein (CRP) level.

Results

The mean patient age at diagnosis was 38.0 years. The mean time interval between RA diagnosis and AAS surgery was 13.6±7.0 years. The risk factors for surgically treated AAS development were the serum CRP level (p=0.005) and radiographic hand joint erosion (p=0.009). The risk factors for AAS progression were a short time interval between RA diagnosis and radiographic hand joint erosion (p<0.001) and young age at RA diagnosis (p=0.04).

Conclusion

The CRP level at RA diagnosis and a short time interval between RA diagnosis and radiographic hand joint erosion might be risk factors for surgically treated AAS development in RA patients. Additionally, a short time interval between RA diagnosis and radiographic hand joint erosion and young age at RA diagnosis might be risk factors for AAS progression.

Effects of a Temperature-Sensitive, Anti-Adhesive Agent on the Reduction of Adhesion in a Rabbit Laminectomy Model

OBJECTIVE

A common cause of failure in laminectomy surgery is when epidural, peridural, or perineural adhesion occurs postoperatively. The purpose of this study is to examine the efficacy of a temperature-sensitive, anti-adhesive agent (TSAA agent), Guardix-SG®, as a mechanical barrier for the prevention or reduction of peridural scar adhesion in a rabbit laminectomy model.

METHODS

Twenty-six mature rabbits were used for this study. Each rabbit underwent two separate laminectomies at lumbar vertebrae L3 and L6, left empty (the control group) and applied 2 mL of the TSAA agent (the experimental group), respectively. Invasive scar formation or inflammation after laminectomy was quantitatively evaluated by measuring the thickness of the dura, the distance from the surface of dura to the scar tissues, the number of inflammatory cells in the scar tissues at the laminectomy site, and the concentration of collagen in histological sections.

RESULTS

At 6 weeks postsurgery, the dura was significantly thinner and the distance from the surface of dura to the scar tissues was greater in the experimental group than in the control group (p=0.04 and p=0.01). The number of inflammatory cells was not significantly different in the two groups (p=0.08), although the mean number of inflammatory cells was relatively lower in the experimental group than in the control group.

CONCLUSION

The current study suggests that the TSAA agent, Guardix-SG®, could be useful as an interpositional physical barrier after laminectomy for the prevention or reduction of adhesion.

A Primary Ossifying Intracranial Myxoma Arising from the Ethmoid Sinus

Myxomas are rare benign tumors that originate from mesenchymal tissue. They usually develop in the atrium of the heart, the skin, subcutaneous tissue, or bone. Involvement of the skull base with an intracranial extension is very rare and not well-described in the literature. We report a rare case of primary intracranial ossifying myxoma arising from the anterior skull base and mimicking a huge chondrosarcoma, and we review the relevant literature.

Bone Flap Resorption Following Cranioplasty after Decompressive Craniectomy: Preliminary Report

Objective

Resorption of autologous bone flap grafts is a known long-term complication of cranioplasty following decompressive craniectomy (DC). We analyzed our data to identify risk factors for bone flap resorption (BFR) following cranioplasty.

Methods

A total of 162 patients who underwent cranioplasty following DC due to life-threatening elevated intracranial pressure between October 2003 and December 2012, were included in our investigation. Follow-up exceeded one year.

Results

BFR occurred as a long-term complication in 9 of the 162 patients (5.6%). The affected patients consisted of individuals who had undergone DC for traumatic brain injury (TBI; n=4), for subarachnoid hemorrhage (SAH; n=3), for cerebral infarction (n=1), and intracerebral hemorrhage (n=1). Logistic regression analysis identified no significant risk factors for BFR.

Conclusion

TBI and SAH as initial diagnoses are more often associated with BFR than other diagnoses. This finding may influence future surgical decision making, especially in patients with possible risk factors for BFR. A prospective study with a large number of patients is needed to identify potential predictors of BFR such as bone flap sterilization and preservation.

Association of total tooth loss with socio-behavioural health indicators in Korean elderly

This study examined the association between total tooth loss, and socio-behavioural factors and general health indicators in elderly Koreans using national databases. Cross-sectional data for this study were from the third Korean National Health and Nutrition Examination Survey (KNHANES III), which was conducted among non-institutionalised civilians by the Korean Ministry of Health and Welfare in 2005. KNHANES III used a stratified, multistage probability sampling design on a representative of total South Korean population, according to geographical areas, age and sex groups. Among them, 1091 subjects aged 65 years and above were identified as potential participants in this study. The dependent variable in this study was the self-reported total tooth loss. The independent variables consisted of the following four categories: demographic information, socio-behavioural factors, psychological factors and general health indicators. The data were weighted to adjust for the sampling complexity, and SPSS version 14 for Windows software was used for data analysis. There were significant differences in total tooth loss odds according to the socio-behavioural backgrounds (education and smoking), psychological conditions (perceived oral health) and general health status (diabetes and body mass index as underweight). This suggests that the total tooth loss is associated with the socio-economic status, health-related behaviour and general health. However, more extensive longitudinal data and research will be needed to better explain the relationship between the total tooth loss and these variables.

Salmonella typhimurium LT2 strains which are r- m+ for all three chromosomally located systems of DNA restriction and modification

We describe the derivation of two strains of Salmonella typhimurium LT2 which are r- m+ for all three of the known chromosomal genes for the restriction and modification of DNA, hsdLT, hsdSA, and hsdSB; the strains were designated LB5000 and LB5010. LB5000 is a smooth derivative sensitive to phage P22; LB5010 is a galE strain sensitive to phage P1.

Ribonucleic acid polymerase mutation affecting glutamate synthase activity in and sporulation of Bacillus subtilis

Spore formation of 15 rifampin-resistant (Rifr) mutants of Bacillus subtilis strain 168 was examined. As a pleiotropic effect of a Rifr mutation, glutamate synthase activity was lost in these mutants. Twelve of the 15 mutants examined formed as many spores as the parent, but the remaining 3 formed significantly fewer (1%) spores. One of the latter mutants characterized further (RF301) was blocked in its sporulation process at stage 0. Thus, it was concluded that a certain modification of ribonucleic acid polymerase may affect specifically the gene expression of glutamate synthase and also the sporulation process at the initial stage.

Pleiotropic effect of a rifampin-resistant mutation in Bacillus subtilis

Rifampin-resistant (Rifr) mutants were isolated spontaneously from Bacillus subtilis strain 168. A fraction of the mutants did not grow on a minimal medium. A high concentration of one of the L-amino acids (glutamic acid, glutamine, arginine, proline, aspartic acid, or asparagine) was required to restore their growth on the medium. Further analysis of one of the mutants (strain RF 161) suggested that the mutant is unable to use ammonia as a nitrogen source and requires amino acids instead. Activity of glutamate synthase was not detected in the crude extract of the mutant. The Rifr mutation was closely located to cysA and the drug resistance was cotransformed with the property of amino acid requirement at 100% frequency. All revertants to prototrophy tested showed the rifampin-sensitive (Rifs) property. The activity of the DNA-dependent RNA polymerase of the mutant was resistant to rifampin. It is concluded that some alteration of RNA polymerase may cause absence of the activity of an enzyme involved in the nitrogen metabolism.