Primary diffuse leptomeningeal gliomatosis

A 20-year-old woman with a history of seizures presented symptoms of walking difficulties for the past six months. Clinical examination was suggestive of a craniovertebral junction anomaly. A cerebrospinal fluid study showed mild protein elevation with no evidence of an infective pathology. Craniospinal MRI revealed diffuse nodular leptomeningeal enhancement of the brain and spinal cord. Histopathological examination was suggestive of a low-grade glioma, and the patient was diagnosed with primary diffuse leptomeningeal gliomatosis. So far, the patient has survived for more than 110 months without aggressive therapy.

Decline in NRF2-regulated antioxidants in chronic obstructive pulmonary disease lungs due to loss of its positive regulator, DJ-1

RATIONALE

Oxidative stress is a key contributor in chronic obstructive pulmonary disease (COPD) pathogenesis caused by cigarette smoking. NRF2, a redox-sensitive transcription factor, dissociates from its inhibitor, KEAP1, to induce antioxidant expression that inhibits oxidative stress.

OBJECTIVES

To determine the link between severity of COPD, oxidative stress, and NRF2-dependent antioxidant levels in the peripheral lung tissue of patients with COPD.

METHODS

We assessed the expression of NRF2, NRF2-dependent antioxidants, regulators of NRF2 activity, and oxidative damage in non-COPD (smokers and former smokers) and smoker COPD lungs (mild and advanced). Cigarette smoke-exposed human lung epithelial cells (Beas2B) and mice were used to understand the mechanisms.

MEASUREMENTS AND MAIN RESULTS

When compared with non-COPD lungs, the COPD patient lungs showed (1) marked decline in NRF2-dependent antioxidants and glutathione levels, (2) increased oxidative stress markers, (3) significant decrease in NRF2 protein with no change in NRF2 mRNA levels, and (4) similar KEAP1 but significantly decreased DJ-1 levels (a protein that stabilizes NRF2 protein by impairing KEAP1-dependent proteasomal degradation of NRF2). Exposure of Bea2B cells to cigarette smoke caused oxidative modification and enhanced proteasomal degradation of DJ-1 protein. Disruption of DJ-1 in mouse lungs, mouse embryonic fibroblasts, and Beas2B cells lowered NRF2 protein stability and impaired antioxidant induction in response to cigarette smoke. Interestingly, targeting KEAP1 by siRNA or the small-molecule activator sulforaphane restored induction of NRF2-dependent antioxidants in DJ-1-disrupted cells in response to cigarette smoke.

CONCLUSIONS

NRF2-dependent antioxidants and DJ-1 expression was negatively associated with severity of COPD. Therapy directed toward enhancing NRF2-regulated antioxidants may be a novel strategy for attenuating the effects of oxidative stress in the pathogenesis of COPD.

DCT-Yager FNN: a novel Yager-based fuzzy neural network with the discrete clustering technique

Earlier clustering techniques such as the modified learning vector quantization (MLVQ) and the fuzzy Kohonen partitioning (FKP) techniques have focused on the derivation of a certain set of parameters so as to define the fuzzy sets in terms of an algebraic function. The fuzzy membership functions thus generated are uniform, normal, and convex. Since any irregular training data is clustered into uniform fuzzy sets (Gaussian, triangular, or trapezoidal), the clustering may not be exact and some amount of information may be lost. In this paper, two clustering techniques using a Kohonen-like self-organizing neural network architecture, namely, the unsupervised discrete clustering technique (UDCT) and the supervised discrete clustering technique (SDCT), are proposed. The UDCT and SDCT algorithms reduce this data loss by introducing nonuniform, normal fuzzy sets that are not necessarily convex. The training data range is divided into discrete points at equal intervals, and the membership value corresponding to each discrete point is generated. Hence, the fuzzy sets obtained contain pairs of values, each pair corresponding to a discrete point and its membership grade. Thus, it can be argued that fuzzy membership functions generated using this kind of a discrete methodology provide a more accurate representation of the actual input data. This fact has been demonstrated by comparing the membership functions generated by the UDCT and SDCT algorithms against those generated by the MLVQ, FKP, and pseudofuzzy Kohonen partitioning (PFKP) algorithms. In addition to these clustering techniques, a novel pattern classifying network called the Yager fuzzy neural network (FNN) is proposed in this paper. This network corresponds completely to the Yager inference rule and exhibits remarkable generalization abilities. A modified version of the pseudo-outer product (POP)-Yager FNN called the modified Yager FNN is introduced that eliminates the drawbacks of the earlier network and yi- elds superior performance. Extensive experiments have been conducted to test the effectiveness of these two networks, using various clustering algorithms. It follows that the SDCT and UDCT clustering algorithms are particularly suited to networks based on the Yager inference rule.

Characterization of an rpoN mutant of Mesorhizobium ciceri

AIMS

To study the genetic basis of C(4)-dicarboxylate transport (Dct) in relation to symbiotic nitrogen fixation in Mesorhizobium ciceri.

METHODS AND RESULTS

A Tn5-induced mutant strain (TL16) of M. ciceri, unable to grow on C(4)-dicarboxylates, was isolated from the wild-type strain TAL 620. The mutant lacked activities of the enzymes, which use C(4)-dicarboxylates as substrate. The sequencing of the 3.2kb EcoRI fragment, which was the site of Tn5 insertion, revealed three complete and two partial open reading frames. In the mutant, Tn5 interrupted the rpoN gene, of which only one copy was there. Complementation and biochemical studies suggest that the M. ciceri rpoN activity is required for C(4)-Dct, maturation of bacteroids and symbiotic nitrogen fixation. The fine structure of the ineffective nodules produced by TL16 on Cicer arietinum L changed in comparison with those produced by the wild type.

CONCLUSIONS

The mutant strain TL16 suffered a disruption in the rpoN gene. Only one copy of rpoN gene is present in M. ciceri. The mutation abolishes Dct activity. It additionally abolishes the symbiotic nitrogen fixation activity of the bacteroids in the nodules.

SIGNIFICANCE AND IMPACT OF THE STUDY

This first document in M. ciceri shows that a functional rpoN gene is essential for the transport of dicarboxylic acids and symbiotic nitrogen fixation.

Does flexible videostroboscopy compare with rigid videostroboscopy in the assessment of the neoglottis? A preliminary report

OBJECTIVE

To evaluate rigid and flexible stroboscopy of the neoglottis.

STUDY DESIGN

Prospective pilot study set at a tertiary level Head & Neck Unit.

PARTICIPANTS

Twenty-four patients recruited. All had undergone a total laryngectomy and were voicing using a Blom-singer valve. All had stroboscopic evaluation of their neoglottis using flexible and rigid endoscopes.

MAIN OUTCOME MEASURES

A rating form was devised based on six parameters with clear definitions. Secondary measures included ability to tolerate the procedure and completeness of the rating form for each parameter using the two systems.

RESULTS

There was good reliability between individual raters for the assessment of each system based on Spearman Rho correlation. Importantly, two-thirds of the patients were unable to tolerate the rigid videostroboscopy managed flexible videostroboscopy. Correlation between rigid and flexible videostroboscopy was poor for both raters. Flexible systems picked up more mucosal waves and allowed further analysis of the mucosal wave pattern.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate that fibreoptic videstroboscopy is as good as rigid videostroboscopy in the assessment of the neoglottis. In fact, flexible videostroboscopy should be routinely used, as it is better tolerated and allows a more detailed analysis of the neoglottis.

Noninvasive molecular neuroimaging using reporter genes: part II, experimental, current, and future applications

SUMMARY

In this second article, we review the various strategies and applications that make use of reporter genes for molecular imaging of the brain in living subjects. These approaches are emerging as valuable tools for monitoring gene expression in diverse applications in laboratory animals, including the study of gene-targeted and trafficking cells, gene therapies, transgenic animals, and more complex molecular interactions within the central nervous system. Further development of more sensitive and selective reporters, combined with improvements in detection technology, will consolidate the position of in vivo reporter gene imaging as a versatile technique for greater understanding of intracellular biologic processes and underlying molecular neuropathology and will potentially establish a future role in the clinical management of patients with neurologic diseases.

Cbl-b regulates antigen-induced TCR down-regulation and IFN-gamma production by effector CD8 T cells without affecting functional avidity

The E3 ubiquitin ligase Cbl-b is a negative regulator of TCR signaling that: 1) sets the activation threshold for T cells; 2) is induced in anergic T cells; and 3) protects against autoimmunity. However, the role of Cbl-b in regulating CD8 T cell activation and functions during physiological T cell responses has not been systematically examined. Using the lymphocytic choriomeningitis virus infection model, we show that Cbl-b deficiency did not significantly affect the clonal expansion of virus-specific CD8 T cells. However, Cbl-b deficiency not only increased the steady-state cell surface expression levels of TCR and CD8 but also reduced Ag-induced down-modulation of cell surface TCR expression by effector CD8 T cells. Diminished Ag-stimulated TCR down-modulation and sustained Ag receptor signaling induced by Cbl-b deficiency markedly augmented IFN-gamma production, which is known to require substantial TCR occupancy. By contrast, Cbl-b deficiency minimally affected cell-mediated cytotoxicity, which requires limited engagement of TCRs. Surprisingly, despite elevated expression of CD8 and reduced Ag-induced TCR down-modulation, the functional avidity of Cbl-b-deficient effector CD8 T cells was comparable to that of wild-type effectors. Collectively, these data not only show that Cbl-b-imposed constraint on TCR signaling has differential effects on various facets of CD8 T cell response but also suggest that Cbl-b might mitigate tissue injury induced by the overproduction of IFN-gamma by CD8 T cells. These findings have implications in the development of therapies to bolster CD8 T cell function during viral infections or suppress T cell-mediated immunopathology.

Assessment of therapeutic response in brain tuberculomas using serial dynamic contrast-enhanced MRI

AIM

To assess the most useful dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) index in the evaluation of the therapeutic response in brain tuberculoma (BT) patients.

SUBJECTS AND METHODS

Twenty-three patients with 25 BT lesions were serially evaluated using DCE MRI. All lesions were classified into two groups: group I (n=15) included patients who showed clinical, as well as imaging, improvement; and group II (n=10) included patients with either clinical or radiological deterioration. The group I and group II lesions were examined for up to 12 months at 4 monthly intervals. However, the lesions in five patients of group II were excised following clinical deterioration after 4 months of therapy. The perfusion indices, i.e., relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), permeability (k(trans)), and leakage (v(e)), were quantified at each time point. The cellular, necrotic, and total volumes of lesion, together with the oedema volume, were also calculated.

RESULTS

All patients in group I and three in group II showed a significant decrease in all perfusion indices, together with the oedema volume, after 1 year. In these three patients in group II, increase in rCBV was associated with increased cellular volume fraction whereas the k(trans), v(e), and oedema volume decreased significantly after 4 months. In five patients in group II who underwent excision of the lesion after 4 months of therapy due to clinical deterioration, the decrease in rCBV was associated with significant increase in k(trans) and oedema volume without any significant change in lesion volume. The rCBV correlated significantly with the cellular volume, whereas k(trans) showed a significant correlation with the v(e) and oedema volume at each time point.

CONCLUSION

In BT, changes in k(trans) and oedema volume are associated with a therapeutic response at 4 months, even when there is a paradoxical increase in the lesion volume.

Küttner's tumour: an unusual cause of salivary gland enlargement

Enlargement of the submandibular gland is a condition that raises the alarm for further investigation as the risk of an underlying malignancy is higher in comparison to parotid gland enlargement. Chronic sclerosing sialadenitis or Küttner's tumour is usually mis-recognised as it is only after excision of the gland that the correct diagnosis is made.We present a case of a 47-year-old male patient who presented with one year history of firm non-tender enlarged right submandibular gland which was removed surgically and histology showed to be sclerosing sialadenitis.Küttner's tumour is a rare disease, which mimics malignancy. There is not enough evidence to support any diagnostic means that could help in the differential diagnosis of this benign condition. Given the high rate of malignancy in firm, painless lesions of the submandibular gland, surgical excision is often advocated and Küttner's tumour is usually diagnosed by the histopathologist.