Outer Membrane Vesicle Proteome of Porphyromonas gingivalis Is Differentially Modulated Relative to the Outer Membrane in Response to Heme Availability.

Porphyromonas gingivalis is an anaerobic, Gram-negative oral pathogen associated with chronic periodontitis. P. gingivalis has an obligate requirement for heme, which it obtains from the host. Heme availability has been linked to disease initiation and progression. In this study we used continuous culture of the bacterium to determine the effect of heme limitation and excess on the P. gingivalis proteome. Four biological replicates of whole cell lysate (WCL) and outer membrane vesicle (OMV) samples were digested with trypsin and analyzed by tandem mass spectrometry and MaxQuant label-free quantification. In total, 1211 proteins were quantified, with 108 and 49 proteins significantly changing in abundance more than 1.5-fold ( p < 0.05) in the WCLs and OMVs, respectively. The proteins most upregulated in response to heme limitation were those involved in binding and transporting heme, whereas the four proteins most upregulated under the heme-excess condition constitute a putative heme efflux system. In general, the protein abundance ratios obtained for OMVs and WCLs agreed, indicating that changes to the OM protein composition are passed onto OMVs; however, 16 proteins were preferentially packaged into OMVs under one condition more than the other. In particular, moonlighting cytoplasmic proteins were preferentially associated with OMVs under heme excess.

Porphyromonas gingivalis and Treponema denticola exhibit metabolic symbioses.

Porphyromonas gingivalis and Treponema denticola are strongly associated with chronic periodontitis. These bacteria have been co-localized in subgingival plaque and demonstrated to exhibit symbiosis in growth in vitro and synergistic virulence upon co-infection in animal models of disease. Here we show that during continuous co-culture a P. gingivalis:T. denticola cell ratio of 6∶1 was maintained with a respective increase of 54% and 30% in cell numbers when compared with mono-culture. Co-culture caused significant changes in global gene expression in both species with altered expression of 184 T. denticola and 134 P. gingivalis genes. P. gingivalis genes encoding a predicted thiamine biosynthesis pathway were up-regulated whilst genes involved in fatty acid biosynthesis were down-regulated. T. denticola genes encoding virulence factors including dentilisin and glycine catabolic pathways were significantly up-regulated during co-culture. Metabolic labeling using 13C-glycine showed that T. denticola rapidly metabolized this amino acid resulting in the production of acetate and lactate. P. gingivalis may be an important source of free glycine for T. denticola as mono-cultures of P. gingivalis and T. denticola were found to produce and consume free glycine, respectively; free glycine production by P. gingivalis was stimulated by T. denticola conditioned medium and glycine supplementation of T. denticola medium increased final cell density 1.7-fold. Collectively these data show P. gingivalis and T. denticola respond metabolically to the presence of each other with T. denticola displaying responses that help explain enhanced virulence of co-infections.

Differential proteomic analysis of a polymicrobial biofilm.

Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia exist in a polymicrobial biofilm associated with chronic periodontitis. The aim of this study was to culture these three species as a polymicrobial biofilm and to determine proteins important for bacterial interactions. In a flow cell all three species attached and grew as a biofilm; however, after 90 h of culture P. gingivalis and T. denticola were closely associated and dominated the polymicrobial biofilm. For comparison, planktonic cultures of P. gingivalis and T. denticola were grown separately in continuous culture. Whole cell lysates were subjected to SDS-PAGE, followed by in-gel proteolytic H2¹6O/H2¹8O labeling. From two replicates, 135 and 174 P. gingivalis proteins and 134 and 194 T. denticola proteins were quantified by LC-MALDI TOF/TOF MS. The results suggest a change of strategy in iron acquisition by P. gingivalis due to large increases in the abundance of HusA and HusB in the polymicrobial biofilm while HmuY and other iron/haem transport systems decreased. Significant changes in the abundance of peptidases and enzymes involved in glutamate and glycine catabolism suggest syntrophy. These data indicate an intimate association between P. gingivalis and T. denticola in a biofilm that may play a role in disease pathogenesis.

Treponema denticola biofilm-induced expression of a bacteriophage, toxin-antitoxin systems and transposases.

Treponema denticola is an oral spirochaete that has been strongly associated with chronic periodontitis. The bacterium exists as part of a dense biofilm (subgingival dental plaque) accreted to the tooth. To determine T. denticola gene products important for persistence as a biofilm we developed a continuous-culture biofilm model and conducted a genome-wide transcriptomic analysis of biofilm and planktonic cells. A total of 126 genes were differentially expressed with a fold change of 1.5 or greater. This analysis identified the upregulation of putative prophage genes in the T. denticola 35405 genome. Intact bacteriophage particles were isolated from T. denticola and circular phage DNA was detected by PCR analysis. This represents the first, to our knowledge, functional bacteriophage isolated from T. denticola, which we have designated varphitd1. In biofilm cells there was also an upregulation of genes encoding several virulence factors, toxin-antitoxin systems and a family of putative transposases. Together, these data indicate that there is a higher potential for genetic mobility in T. denticola when growing as a biofilm and that these systems are important for the biofilm persistence and therefore virulence of this bacterium.

Detecting Predeath Grief in Family Caregivers of Persons With Dementia: Validity and Utility of the Marwit-Meuser Caregiver Grief Inventory in a Multiethnic Asian Population.

Background and Objectives: Coping with predeath grief (PDG) is an unmet need in caregivers of persons with dementia (PWD). The Marwit-Meuser Caregiver Grief Inventory (MM-CGI) and its abbreviated MM-CGI-Short-Form (MM-CGI-SF) are among the few empirically developed scales that detect PDG, yet they have not been substantially validated outside United States. We evaluated the reliability and validity of the PDG scales in a multiethnic Asian population distinct from that of United States. Research Design and Methods: Family caregivers of community-dwelling PWD (n = 300) completed self-administered questionnaires containing MM-CGI and other scales of related construct. Sixty percent of the participants repeated the questionnaires 1 week later for test-retest reliability. Internal-consistency reliability was assessed by Cronbach's α, test-retest reliability by intraclass-correlation-coefficient, construct validity by Spearman's correlation-coefficient, and factorial validity by confirmatory factor analysis (CFA). Cohen's κ was used to compare the agreement between MM-CGI and a commonly-used caregiver burden scale (Zarit Burden Interview). Results: MM-CGI and MM-CGI-SF demonstrated internal-consistency reliability, test-retest reliability, construct validity, and known-group validity. In CFA, MM-CGI showed modest model-fit (comparative-fit-index, CFI = .80; Tucker-Lewis-index, TLI = .79), whereas MM-CGI-SF showed better model-fit (CFI = .91; TLI = .90). Eighty-six percent of the caregivers reported average or high levels of PDG, with 18% reporting high PDG. High scores in the caregiver burden scale only showed modest agreement with high scores in MM-CGI (κ = .47). Discussion and Implications: MM-CGI and MM-CGI-SF demonstrated adequate psychometric properties and utility, beyond that of a caregiver burden scale, in detecting high PDG in a multiethnic Asian population. They open the way for PDG intervention in clinical care, as well as further exploration in caregiver research.

Hemangiopericytoma of the thoracic spine: a case report.

Hemangiopericytoma (HPC) has been described to be aggressive and potentially a malignant tumour. We report a rare case of a 63-year-old Chinese male who presented with primary intradural extramedullary HPC of the thoracic spine. The main presenting complaint was gradual progression of back pain, associated with paraparesis and sensory deficit of lower limbs. He had MRI thoracolumbar with contrast which showed T9 lesion compressing on spinal cord and oedema, he was then operated upon and histopathology report confirmed a thoracic spine HPC. A T8/9 laminectomy and excision of intradural extramedullary lesion was performed, tumour section was sent for frozen section study, and more tissue was sent for paraffin studies and additional immunohistochemical staining. Surgical resection is most commonly performed, radiotherapy remains debatable. In this report, we discussed another rare case of primary spinal HPC to be added into the literature.

Effect of azithromycin on a red complex polymicrobial biofilm.

Azithromycin has recently gained popularity for the treatment of periodontal disease, despite sparse literature supporting efficiency in treating periodontal bacterial biofilms. The aim of this study was to evaluate the effect of azithromycin on biofilms comprised of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in comparison to an amoxicillin and metronidazole combination. P. gingivalis W50, T. denticola ATCC35405, and T. forsythia ATCC43037 grown under anaerobic conditions at 37°C were aliquoted into 96-well flat-bottom plates in different combinations with addition of azithromycin or amoxicillin + metronidazole at various concentrations. For the biofilm assay, the plates were incubated at 37°C anaerobically for 48 h, after which the biofilms were stained with crystal violet and measured for absorbance at AU620. In this model, polymicrobial biofilms of P. gingivalis + T. denticola, P. gingivalis + T. forsythia, and T. denticola + T. forsythia were cultured. Combination of all three bacteria enhanced biofilm biomass. Azithromycin demonstrated a minimal biofilm inhibitory concentration (MBIC) of 10.6 mg/L, while the amoxicillin + metronidazole combination was more effective in inhibiting biofilm formation with a MBIC of 1.63 mg/L. Polymicrobial biofilm formation was demonstrated by combination of all three red complex bacteria. Azithromycin was ineffective in preventing biofilm formation within a clinically achievable concentration, whereas the combination of amoxicillin and metronidazole was more effective for this purpose.

Disseminated spread of recurrent oligodendroglioma (WHO grade II).

Oligodendroglioma is a relatively uncommon primary brain tumour. The occurrence of metastatic dissemination of oligodendroglioma is rare and usually occurs in patients with anaplastic oligodendroglioma. The dissemination of WHO Grade II oligodendroglioma can occur and we report a patient with an initial diagnosis of a left temporal oligodendroglioma who presented with disseminated disease in the left temporal lobe, sellar region, medulla oblongata, both frontal lobes and ventricles more than 8 years later. Histology at dissemination showed anaplastic oligodendroglioma. Similar reports of metastatic dissemination of oligodendrogliomas reveal that the tumours may remain as WHO Grade II or may progress to anaplastic oligodendroglioma at metastasis. However, regardless of the histological grade at metastasis, the prognosis of metastatic oligodendroglioma is poor.

The potential acidogenicity of liquid breakfasts.

OBJECTIVES: To determine the potential acidogenicy of liquid breakfasts. METHODS: In vitro acid production by Streptococcus mutans was measured in the beverages at a pH of 5.5, as was the fall in pH over 10min. The buffering capacity was determined, as well as the calcium, inorganic phosphate and fluoride concentrations (total and soluble) of the beverages. Bovine milk (UHT) was used for comparison. RESULTS: The rate of acid production by S. mutans, and pH fall over 10min was greater in liquid breakfasts compared to bovine milk. All beverages except one demonstrated a significantly lower buffering capacity than bovine milk. All beverages contained significantly greater concentrations of soluble calcium than bovine milk, and all except two contained significantly more soluble inorganic phosphate. CONCLUSIONS: S. mutans was able to generate significantly more acid in the liquid breakfasts than in bovine milk, indicating these drinks may contribute to a cariogenic diet. In general, the liquid breakfasts required significantly less acid than bovine milk to reduce their pH to the approximate critical pH for enamel demineralisation. However, the liquid breakfasts also tended to contain significantly more soluble calcium and inorganic phosphate than bovine milk. CLINICAL SIGNIFICANCE: The substantial amounts and various types of sugars found within liquid breakfast beverages may result in a significant pH drop in dental plaque following consumption of these products.

Giant spinal ganglioneuroma.

Ganglioneuromas are rare benign tumours, which may affect any part of the spine and spinal cord. They occasionally grow to a large size but total excision using microsurgical techniques is often possible, and may be curative. This case report illustrates the clinical and histopathological features of two rare giant ganglioneuromas of the spinal cord.

Spinal schwannoma with acute subarachnoid hemorrhage: a diagnostic challenge.

We report a case of spinal intradural schwannoma presenting with intracranial subarachnoid hemorrhage. Cerebral angiography studies were negative, but MR imaging of the spine revealed a large hemorrhagic tumor in the thoraco-lumbar junction. The tumor was misdiagnosed as ependymoma of the conus medullaris. This case illustrates the importance of a high index of suspicion for spinal disease in angiographically-negative subarachnoid hemorrhage and pitfalls in MR diagnosis of thoraco-lumbar tumors.

MR imaging features of pigmented villonodular synovitis of the cervical spine.

Pigmented villonodular synovitis (PVNS) is a benign proliferative disorder primarily occurring in the large joints of the appendicular skeleton such as the knee and hip joints. We present an unusual case of PVNS involving the cervical spine in an adult. MR imaging showed an enhancing mass lesion arising from the posterior elements of the cervical spine and hyperintensity on the T2-weighted images, without evidence of T2 susceptibility effects. Gross total excision of the tumor was performed, and the diagnosis was established by histopathology.

C1-C2 tuberculosis: a case report.

Tuberculosis of the atlantoaxial spine is a rare condition that is often overlooked and remains a diagnostic dilemma. We report the rare case of a 56-year-old woman with cervical myelopathy secondary to a lytic lesion of C1-C2 complex with a histological diagnosis of tuberculosis.

Spinal epidural haematoma: MRI-aided diagnosis.

Spinal epidural haematoma is a rare cause of spinal cord compression. It is most commonly attributed to trauma and coagulation disorders. We report a case of a 64 year-old man with thrombocytopaenia who presented with a traumatic epidural haematoma who p resented with right hemiparesis which progressed to complete tetraplegia. MR of the cervical spine showed an epidural collection on the posterior aspect of the cord throughout the cervical spine. The patient underwent C1-C7 laminectomy and decompression. Postoperatively, the patient has improved gradually and has power of grade 3 (Medical Research Council classification of power) in all 4 limbs at 2-month follow-up. MRI is an important modality in the early diagnosis of spinal epidural haematomas and can facilitate emergent decompressive surgery which offers the best chance of neurological improvement.

Study of lumbar disc pathology among a group of dockworkers.

Low back disorders pose a serious health problem among workers engaged in heavy manual lifting and carrying. In order to determine the extent to which this type of activity may contribute to the prevalence and pattern of lumbar disc degeneration, a group of dockworkers doing heavy lifting and carrying and a control group of clerks were compared. The prevalence of disc changes was higher among the dockworkers at all disc levels studied (T12-L5). No significant differences in pattern of distribution of affected discs were demonstrated. A higher prevalence of anterior and posterior disc changes, occurring more in combination than singly, was observed in the dockworkers. There was a significant excess of such combined changes in the T12, L4 and L5 discs among the dockworkers, compared with only L5 involvement in the controls.

Functionalized curcumin analogs as potent modulators of the Wnt/ß-catenin signaling pathway.

Osteosarcoma is a primary bone malignancy with aggressive metastatic potential and poor prognosis rates. In our earlier work we have investigated the therapeutic potential of curcumin as an anti-invasive agent in osteosarcoma by its ability to regulate the Wnt/ß-catenin signaling pathway. However, the clinical use of curcumin is limited owing to its low potency and poor pharmacokinetic profile. In this study, an attempt was made to achieve more potent Wnt inhibitory activity in osteosarcoma cells by carrying out synthetic chemical modifications of curcumin. We synthesized a total of five series consisting of 43 curcumin analogs and screened in HEK293T cells for inhibition of ß-catenin transcriptional activity. Six promising analogs, which were 6.5- to 60-fold more potent than curcumin in inhibiting Wnt activity, were further assessed for their anti-invasive activity and Wnt inhibitory mechanisms. Western blot analysis showed disruption of ß-catenin protein nuclear translocation following treatment with analogs 2f, 3c and 4f. Using transwell assays, we also found that these compounds were more potent than 1a (curcumin) in impeding the invasion of osteosarcoma cells, possibly through suppressing MMP-9 activity. Structure-activity-relationship studies revealed that Wnt inhibitory effects could be enhanced by shortening and restraining the flexibility of the 7-carbon linker moiety connecting the terminal aromatic rings of curcumin and substituting both rings with appropriate substituents. Our results demonstrate that the synthesized curcumin analogs are more potent Wnt inhibitors in osteosarcoma cell lines as compared to parental curcumin and are good lead compounds for further development. Future in vivo tests with these compounds will define their therapeutic potentials as promising drug candidates for clinical treatment of osteosarcoma.

Synthesis and evaluation of bisbenzylidenedioxotetrahydrothiopranones as activators of endoplasmic reticulum (ER) stress signaling pathways and apoptotic cell death in acute promyelocytic leukemic cells.

Curcumin is known to trigger ER-stress induced cell death of acute promyelocytic leukemic (APL) cells by intercepting the degradation of nuclear co-repressor (N-CoR) protein which has a key role in the pathogenesis of APL. Replacing the heptadienedione moiety of curcumin with a monocarbonyl cross-conjugated dienone embedded in a tetrahydrothiopyranone dioxide ring resulted in thiopyranone dioxides that were more resilient to hydrolysis and had greater growth inhibitory activities than curcumin on APL cells. Several members intercepted the degradation of misfolded N-CoR and triggered the signaling cascade in the unfolded protein response (UPR) which led to apoptotic cell death. Microarray analysis showed that genes involved in protein processing pathways that were germane to the activation of the UPR were preferentially up-regulated in treated APL cells, supporting the notion that the UPR was a consequential mechanistic pathway affected by thiopyranone dioxides. The Michael acceptor reactivity of the scaffold may have a role in exacerbating ER stress in APL cells.

Nfil3 is a glucocorticoid-regulated gene required for glucocorticoid-induced apoptosis in male murine T cells.

Glucocorticoids (GCs) have essential roles in the regulation of development, integrated metabolism, and immune and neurological responses, and act primarily via the glucocorticoid receptor (GR). In most cells, GC treatment results in down-regulation of GR mRNA and protein levels via negative feedback mechanisms. However, in GC-treated thymocytes, GR protein levels are maintained at a high level, increasing sensitivity of thymocytes to GCs, resulting in apoptosis termed glucocorticoid-induced cell death (GICD). CD4(+)CD8(+) double-positive thymocytes and thymic natural killer T cells in particular are highly sensitive to GICD. Although GICD is exploited via the use of synthetic GC analogues in the treatment of hematopoietic malignancies, the intracellular molecular pathway of GICD is not well understood. To explore GICD in thymocytes, the authors performed whole genome expression microarray analysis in mouse GR exon 2 null vs wild-type thymus RNA 3 hours after dexamethasone treatment. Identified and validated direct GR targets included P21 and Bim, in addition to an important transcriptional regulator Nfil3, which previously has been associated with GICD and is essential for natural killer cell development in vivo. Immunostaining of NFIL3 in whole thymus localized NFIL3 primarily to the medullary region, and double labeling colocalized NFIL3 to apoptotic cells. In silico analysis revealed a putative GC response element 5 kb upstream of the Nfil3 promoter that is strongly conserved in the rat genome and was confirmed to bind GR by chromatin immunoprecipitation. The knockdown of Nfil3 mRNA levels to 20% of normal using specific small interfering RNAs abrogated GICD, indicating that NFIL3 is required for normal GICD in CTLL-2 T cells.

Infratentorial benign cystic meningioma mimicking a hemangioblastoma radiologically and a pilocytic astrocytoma intraoperatively: a case report.

INTRODUCTION: Cystic meningiomas are rare variants of meningiomas; they can pose a radiological diagnostic dilemma. CASE PRESENTATION: We present a rare case of a 30-year-old Chinese woman with a histopathological diagnosis of infratentorial cystic meningioma (World Health Organization Grade 1) in which the features in imaging modalities were suggestive of a hemangioblastoma. Intraoperatively, however, the gross macroscopic features were more in keeping with a pilocytic astrocytoma. CONCLUSION: In benign cystic meningiomas, particularly the infratentorial variety, radiological findings utilizing the various imaging modalities and intraoperative impressions may not be reflective of or in keeping with the final histopathological diagnosis.

Spinal cavernous malformations: magnetic resonance imaging and associated findings.

INTRODUCTION: We reviewed the clinical features, brain and spinal cord magnetic resonance (MR) imaging findings and associated abnormalities in six patients with spinal cavernous malformations (CMs). METHODS: Lesions were defined on gradient-recalled echo (GRE) images but measured on T2-weighted images performed on 1.5- and 3-tesla clinical scanners. RESULTS: Four patients had associated multiple cranial CMs and one patient had multiple spinal CMs. All spinal CMs were predominantly hypointense on GRE images, and most were predominantly hyperintense and surrounded by hypointense edge on T2-weighted images. Other associations included asymptomatic vertebral body and splenic haemangiomas. CONCLUSION: We conclude that intramedullary spinal CMs typically have 'mulberry' or 'popcorn' appearances similar to those of cranial CM. The presence of associated haemangioma or familial cranial CM syndrome on MR imaging may suggest the correct diagnosis without requiring invasive investigations.