Does Gadolinium Deposition Lead to Metabolite Alteration in the Dentate Nucleus? An MRS Study in Patients with MS

BACKGROUND AND PURPOSE

Repeat contrast-enhanced MR imaging exposes patients with relapsing-remitting MS to frequent administration of gadolinium-based contrast agents. We aimed to investigate the potential metabolite and neurochemical alterations of visible gadolinium deposition on unenhanced T1WI in the dentate nucleus using MRS.

MATERIALS AND METHODS

This prospective study was conducted in a referral university hospital from January 2020 to July 2021. The inclusion criteria for case and control groups were as follows: 1) case: patients with relapsing-remitting MS, visible gadolinium deposition in the dentate nucleus (ribbon sign), >5 contrast-enhanced MR images obtained; 2) control 1: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, >5 contrast-enhanced MR images obtained; 3) control 2: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, <5 contrast-enhanced-MR images obtained; and 4) control 3: adult healthy individuals, with no contrast-enhanced MR imaging. Dentate nucleus and pontine single-voxel 12 × 12 × 12 MRS were analyzed using short TEs.

RESULTS

Forty participants (10 per group; 27 [67.5%] female; mean age, 35.6 [SD, 9.6] years) were enrolled. We did not detect any significant alteration in the levels of NAA and choline between the studied groups. The mean concentrations of mIns were 2.7 (SD, 0.73) (case), 1.5 (SD, 0.8) (control 1), 2.4 (SD, 1.2) (control 2), and 1.7 (SD, 1.2) (control 3) (P = .04). The mean concentration of Cr and mIns (P = .04) and the relative metabolic concentration (dentate nucleus/pons) of lipid 1.3/Cr (P = .04) were significantly higher in the case-group than in healthy individuals (controls 1-3). Further analyses compared the case group with cumulative control 1 and 2 groups and showed a significant increase in lactate (P = .02), lactate/Cr (P = .04), and Cr (dentate nucleus/pons) (P = .03) in the case group.

CONCLUSIONS

Although elevated concentrations of Cr, lactate, mIns, and lipid in the dentate nucleus of the case group indicate a metabolic disturbance, NAA and choline levels were normal, implying no definite neuronal damage.

The Complete Response of a Renal Cell Carcinoma Metastatic to Brain, Lungs, and Liver to Second-Line Nivolumab: A Case Report

Metastatic renal cell carcinoma (RCC) is a therapeutic challenge to clinicians since it shows significant resistance to chemotherapy and radiation therapy. With the introduction of immunotherapy, the treatment paradigm for RCC has evolved. Here, we describe the case of a 55-year-old male who presented with flank pain. An abdominal-pelvic computed tomography (CT) scan revealed a right renal mass. Following open right radical nephrectomy, first-line treatment with sunitinib was administered. After four months he developed multiple metastases to the liver, lungs, abdominal wall, and brain. He initiated second-line treatment with nivolumab and also received whole brain radiation therapy (WBRT). Six months following combined treatment with nivolumab and WBRT, a CT scan revealed complete radiologic response in the lungs, abdominal wall, brain, and liver except for the persistence of a subhepatic mass. Despite the discontinuation of nivolumab and starting bevacizumab due to financial problems, the patient was stable for 22 months, and after this, he was hospitalized with high bilirubin levels. An abdominal CT scan detected the development of the necrotic subhepatic mass compressing the common bile duct (CBD), with no other sign of metastatic disease. We believe that the explanation for this long-term disease control could be the combination of immune-checkpoint-inhibitor (ICI) with WBRT resulting in significant cranial and extracranial immune response, known as "the abscopal effect". This report highlights the importance of local therapy combined with ICI-based therapy in metastatic RCC.

Late-onset neuromyelitis optica spectrum disorder: A case series from Iran

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is a disabling autoimmune disease of the central nervous system that can start at ages of 50 or more, when it is called late-onset NMOSD (LO-NMOSD). Data on this disorder are sparse. In this cross-sectional study, patient characteristics of the disease were studied. LO-NMOSD patients of a tertiary center in Tehran were studied from 2016 to 2020.

CASE REPORTS

Eight patients were identified, half of whom were men. The diagnostic delay was from no time-lapse to three years (mean: 0.62, SD: 1.06), which was significantly shorter than in early-onset patients. Seven patients (87.5%) tested positive for AQP4-IgG which was significantly higher compared to early-onset patients (p-value=0.01). Four patients (50%) had both transverse myelitis and optic neuritis as presenting symptoms, while three (38%) had just myelitis and only one (12%) had optic neuritis.

CONCLUSION

There is discrepancy regarding different aspects of LO-NMOSD. Further studies are needed to clarify the subject in order to enhance diagnosis and treatment.

Intra-hospital dissemination of clinical and environmental isolates of Stenotrophomonas maltophilia from Tehran

Stenotrophomonas maltophilia isolates are responsible for various hospital-acquired infections and are particularly increasing in the immunocompromised patients. The aim of this study was to determine the clonal relatedness between S. maltophilia isolates originating from the clinic and environment. A total of 150 S. maltophilia isolates from patients and 1108 environmental samples obtained in three hospitals from Tehran. Following molecular identification targeting 23S rRNA gene, the clonal relatedness of the environmental and clinical isolates was determined using pulsed field gel electrophoresis (PFGE). Of the 150 clinical and 18 environmental isolates identified using phenotypic tests, the speciation of 120 and 15 was confirmed by targeting the 23S rRNA gene. The 24 common pulsotypes (PTs) and 32 single PTs were identified by PFGE. Only a small cluster was shared among the clinic and environment within a hospital; therefore, the intra-hospital dissemination of certain isolates of S. maltophilia among the clinic and environment was demonstrated.

PPAR-gamma in overcoming kinase resistance in chronic myeloid leukemia

Peroxisome proliferator-activated receptor gamma (PPARγ) plays key roles in regulating cellular differentiation, proliferation and apoptosis pathways. As such, they are considered promising targets for anticancer drug development, especially for breast cancer, multiple myeloma and hematologic malignancies. Chronic myeloid leukemia (CML) is a myeloproliferative disorder arising from an oncogenic Bcr-Abl tyrosine kinase. Inhibitors of this oncogene by small molecules such as imatinib are effective only in 75% of the patient's population. One of the potential strategies to overcome this resistance is to devise combination therapy protocols with other therapeutic agents including PPAR ligands. Since PPAR ligands are potentially interesting in different hematologic malignancies, this article will review the potential of PPAR ligands for use in CML treatment.

The Effect of Prednisolone on miR 15a and miR16-1 Expression Levels and Apoptosis in Acute Lymphoblastic Leukemia Cell Line: CCRF-CEM

BACKGROUND

Glucocorticoids are probably the most important drugs in the treatment of childhood acute lymphoblastic leukemia (ALL). Prednisolone exerts its effect by induce apoptosis in lymphoid lineage cells. Micro RNAs are 18-24 nucleotides RNA implicated in the control of essential biological functions, including apoptosis. In the following study, the effect of prednisolone on the expression of miR 15a & miR16-1 and apoptosis in the CCRF-CEM cell line is investigated.

METHODS

The cell line of CCRF-CEM was cultured in standard conditions. The changes in the miR 15a and miR 16-1 expression levels were determined by Real Time-PCR technique. Also, the apoptosis is evaluated by flow cytometry using Annexin V and PI staining.

RESULTS

This study revealed that, the prednisolone induced apoptosis in a time dependent manner. Prednisolone in concentration of 700 µM was significantly increased the expression of miR 16-1 and miR 15a after 24 h and 48 h treatment (p<0.05).

CONCLUSION

prednisolone-induced apoptosis might be mediated by up-regulation of these 2 miRNAs in CCRF-CEM cells.

Proteomics analysis of melanoma metastases: association between S100A13 expression and chemotherapy resistance

BACKGROUND

Disseminated cutaneous malignant melanoma (CMM) is commonly unresponsive to standard chemotherapies, and there are as yet no predictive markers of therapy response.

METHODS

In the present study we collected fresh-frozen pretreatment lymph-node metastasis samples (n=14) from melanoma patients with differential response to dacarbazine (DTIC) or temozolomide (TMZ) chemotherapy, to identify proteins with an impact on treatment response. We performed quantitative protein profiling using tandem mass spectrometry and compared the proteome differences between responders (R) and non-responders (NR), matched for age, gender and histopathological type of CMM.

RESULTS

Biological pathway analyses showed several signalling pathways differing between R vs NR, including Rho signalling. Gene expression profiling data was available for a subset of the samples, and the results were compared with the proteomics data. Four proteins with differential expression between R and NR were selected for technical validation by immunoblotting (ISYNA1, F13A1, CSTB and S100A13), and CSTB and S100A13 were further validated on a larger sample set by immunohistochemistry (n=48). The calcium binding protein S100A13 was found to be significantly overexpressed in NR compared with R in all analyses performed.

CONCLUSIONS

Our results suggest that S100A13 is involved in CMM resistance to DTIC/TMZ.

Effects of dominant/subordinate social status on formalin-induced pain and changes in serum proinflammatory cytokine concentrations in mice

Current investigations regarding social stress primarily focus on the health consequences of being in stressful social hierarchies. The repetitive nature of social conflicts seems to favor an induction of hyperalgesia or hypoalgesia, both in rodents and humans. Additionally, social conflicts may affect the immune system. In order to better establish the pain and immune responses to stress, the present study implemented a sensory contact model on 32 male BALB/c mice. Subsequent to establishing a dominance/submissive social relationship, each mouse was injected with formalin (20 μl, 2%) and their pain behavior was scored and serum concentrations of proinflammatory cytokines IL-1 and IL-6, and corticosterone were also measured. Test results revealed that subordinate mice were hypoalgesic during chronic phase of formalin test compared to control and dominant mice (P<0.05). On the other hand, subordinate mice were hyperalgesic compared to dominant mice during the whole acute phase of formalin test (P<0.05). Corticosterone, IL-1 and IL-6 concentrations were much higher in serum of dominant and subordinate mice than in the control group (p<0.05). The results indicated that, although both dominant and subordinate animals displayed an increase in serum corticosterone and proinflammatory cytokines during social interactions, their response to pain perception differently was affected with the social status.

Simultaneous pattern visual evoked potential and pattern electroretinogram in strabismic and anisometropic amblyopia

BACKGROUND

Amblyopia is a relatively common condition in which visual acuity through an eye is subnormal despite no overt pathology. Pattern visual evoked potential (PVEP) can detect any defect from optic nerve to occipital cortex and pattern electroretinogram (PERG) can detect retinal defects specially the ganglion layers. This study was performed to evaluate the cortical and retinal activity in strabismic and anisometropic amblyopia.

METHODS

PVEP and PERG were recorded simultaneously in 40 amblyopes (20 strabismics and 20 anisometropics) and 20 normal control subjects. Normal subjects were age and sex matched with patients.

RESULTS

The P(100) latency in PVEP was increased in both groups of patients but the P(100) amplitude was reduced only in anisometropic group. In PERG, the amplitude of P(50) was reduced in all patients with no significant change in latency.

CONCLUSION

Beside reduced PVEP responses in strabismic and anisometropic amblyopia, the activity of retina reduced too. It is likely that retinal impulses can affect the development of visual system.

Nitric oxide effects on myocardial function and force-interval relations: regulation of twitch duration

As the precise role of nitric oxide (NO) as a modulator of myocardial contraction and the force-interval relationship remains unclear, the objective of this study was to examine the effect of the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) on baseline myocardial contraction, and the impact of both SNAP and the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) on the force interval relation. Studies were performed using isolated rat papillary muscles. In the presence of baseline NOS blockade, nanomolar to micromolar concentrations of SNAP exerted a modest positive inotropic effect with a small but significant increase in twitch isometric tension (P<0.007). Nanomolar concentrations of SNAP also reduced overall twitch duration (P<0.007). These effects were not seen in control experiments using N-acetyl-penicillamine instead of SNAP. The force-frequency response (FFR) and post-rest contractile potentiation, mechanical correlates of sarcoplasmic reticulum (SR) Ca(2+)handling, were also examined. Neither L-NAME nor SNAP had any effect on post-rest potentiation following rest intervals as long as 6 min, or on the negative FFR at stimulation frequencies between 0.3 to 1.7 Hz. However, L-NAME significantly blunted the net reduction in twitch duration between 0.3 Hz and 1.7 Hz compared to control (P=0.006), an effect reversed by 100 n m SNAP. These results indicate that low concentrations of NO can modulate myocardial function by influencing myocardial inotropy and the time course of myofilament interaction, but do not impact significantly on the force-interval relation and, by inference, SR Ca(2+)handling. Moreover, modulation of twitch duration occurs over a range of stimulation frequencies, suggesting a mechanistic role for NO in the changes in contraction and relaxation time intervals seen during changes in heart rate.

Proximally induced accommodation and accommodative adaptation

To determine the effect of proximally induced accommodation (PIA) on accommodative adaptation, this study has examined the posttask shift in tonic accommodation (TA) following 5-min monocular viewing of equivalent-sized targets located at distances of 0.33 and 5 m. The distal target was viewed through a negative lens to equate the dioptric stimuli (3 D). The steady-state accommodative response was measured subjectively in 10 subjects using a Hartinger coincidence optometer. A significant correlation was observed between the degree of adaptation following the two conditions, with the magnitude of adaptation for the distal target being approximately half that for the nearer target. Furthermore, adaptation magnitude was inversely correlated with pretask TA under both conditions. These results indicate that PIA can produce accommodative adaptation. The implications of this finding are discussed with regard to models of the accommodative mechanism.

Accommodative responses to naturalistic stimuli

Steady-state accommodative responses to a wide range of commonly encountered textural and graphic stimuli were investigated in 12 young, visually normal subjects. Details of two experiments are described. In the first experiment, stimuli were varied in terms of size, contrast, spatial frequency, colour and intellectual demand. In the second experiment, only the colour of the targets was systematically altered. In both experiments the stimulus demand was maintained at 3 D, and accommodation was measured subjectively using a Hartinger coincidence optometer. No significant difference in mean accommodative response was observed between the widely differing targets adopted in either experiment. These findings suggest that an overall threshold exists for accommodative stimuli, with supra-threshold targets of low to moderate contrast being capable of initiating and sustaining an appropriate accommodative response.