Ethambutol neuroretinopathy

OBJECTIVE: To describe the clinical features of ethambutol neuroretinopathy. DESIGN: Case report and meta-analysis of the literature. PARTICIPANTS: A patient with clinical and electrophysiological findings suggestive of ethambutol neuroretinopathy. TESTING: Electroretinogram, electro-oculogram and visual fields. MAIN OUTCOME MEASURE: Clinical and electrophysiological findings. RESULTS: 101 cases were reviewed, retinal findings include retinal pigment epithelial changes, macular edema, flame-shaped hemorrhages. Electroretinogram findings include decreased amplitude and abnormal wave pattern in full field ERG, multifocal or pattern ERG and electro-oculogram findings include abnormal Arden ratio. CONCLUSIONS: Clinical, electrophysiological and in vitro studies support the toxic effect of ethambutol on the retina. Therefore ethambutol ocular toxicity may be a neuroretinopathy.     

The influence of human leukocyte antigen and IL-10 gene polymorphisms on hepatitis B virus outcome

Context

The clinical outcome of hepatitis B virus (HBV) infection is variable, ranging from spontaneous recovery to an inactive carrier state, chronic hepatitis, occult HBV infection, liver cirrhosis, or hepatocellular carcinoma.

Evidence Acquisition

This variable pattern and clinical outcomes of the infection were mainly determined by virological and host genetic factors. Since the most of host genetic factors associated with HBV infection have currently focused on human leukocyte antigen (HLA) associations and interleukin (IL)-10 gene polymorphisms, this review focuses on the recent progresses in these issues to provide prognostic markers for the outcome of HBV infection.

Results

A study on serum levels of IL-10 in occult HBV infected patients reported that the higher level of IL-10 production may suppress function of the immune system against HBV in patients with occult HBV infection. IL-10 promoter polymorphism at position -592 is associated with susceptibility to occult HBV infection.

Conclusions

Findings of this study suggest that the host HLA polymorphism is an important factor in determining outcome of HBV infection but regarding IL-10 gene promoter polymorphisms, we are still have a long way to achieve a definite conclusion.     

Fever and Psychosis as an Early Presentation of Brucella-Associated Meningoencephalitis: A Case Report

Objective

To describe a case with Brucella-associated meningoencephalitis. In addition, we report drug-induced hepatotoxicity due to acyclovir.

Clinical Presentation and Intervention

A young woman was admitted with fever and psychosis and neuroimaging findings indicative of meningoencephalitis. Serology was positive for Brucella. She was treated with doxycycline, rifampin, and trimethoprim-sulfamethoxazole.

Conclusion

This case reminds physicians in endemic regions to consider neurobrucellosis as a differential diagnosis in patients with any unexplained neurologic symptoms or atypical psychosis. Early diagnosis and treatment of neurobrucellosis will be helpful in decreasing the sequelae of this complication.Key Words: Brucellosis, Meningoencephalitis, Psychosis, Acyclovir, Hepatotoxicity     

Downregulation of Calcineurin Gene Is Associated with Glucantime? Resiatance in Leishmania infantum

Background

Pentavalent antimonials are the first line drugs for the treatment of leishmaniasis. Unresponsiveness of Leishmania spp. to antimonial drugs is a serious problem in some endemic areas. Investigations on molecular mechanisms involved in drug resistance are essential for monitoring and managing of the disease. Cal-cineurin is an essential protein phosphatase for number of signal transduction pathways in eukaryotic cells and it has a mediated role in apoptosis. This study aimed to determine of biomarker(s) in Glucantime^® resiatance strain of L. infan-tum.

Methods

We used cDNA amplified fragment length polymorphism (cDNA-AFLP) and real time-RT PCR assays to compare gene expression profiles at the mRNA levels in resistant and susceptible L. infantum field isolates.

Results

The cDNA-AFLP results showed downlegulation of calcineurin in resis-tant isolate in comparison with susceptible one. Significant downregulation of cal-cineurin (0.42 fold) (P<0.05) was found in resistant isolate compared to susceptible one by Real time-RT PCR.

Conclusion

This is the first report of calcineurin implication in Glucantime^® drug resistance of field (natural) isolate of L. infantum. Downregulation of calcineurin could protect parasites from antimonial-induced apoptosis.     

Intrinsic physiology of identified neurons in the prepositus hypoglossi and medial vestibular nuclei

Signal processing in the vestibular system is influenced by the intrinsic physiological properties of neurons that differ in neurotransmitters and circuit connections. Do membrane and firing properties differ across functionally distinct cell types? This study examines the intrinsic physiology of neurons in the medial vestibular nucleus (MVN) and nucleus prepositus hypoglossi (NPH) which express different neurotransmitters and have distinct axonal projections. NPH neurons expressing fluorescent proteins in glutamatergic, glycinergic, or GABAergic neurons were targeted for whole-cell patch recordings in brainstem slices obtained from transgenic mouse lines (YFP-16, GlyT2, and GIN). Recordings from MVN neurons projecting to the spinal cord, reticular formation, or oculomotor nucleus were obtained by targeting fluorescent neurons retrogradely labeled from tracer injections. Intrinsic physiological properties of identified neurons exhibited continuous variations but tended to differ between functionally defined cell types. Within the NPH, YFP-16 neurons had the narrowest action potentials and highest evoked firing rates and expressed high levels of Kv3.3 proteins, which speed repolarization. MVN neurons projecting to the spinal cord and oculomotor nucleus had similar action potential waveforms, but oculomotor-projecting neurons had higher intrinsic gains than those projecting to the spinal cord. These results indicate that intrinsic membrane properties are differentially tuned in MVN and NPH neurons subserving different functions.     

Lethal toxic encephalopathy due to childhood shigellosis or Ekiri syndrome

Lethal toxic encephalopathy due to shigellosis or Ekiri syndrome is a rare complication of shigellosis with a high fatality rate. Data are very limited on factors that can predict this encephalopathy, so we evaluated clinical and laboratory characteristics for these patients. In this study children with extreme toxicity and convulsions followed by rapid neurological deterioration resulting in brain edema and fatal outcome without sepsis and severe dehydration were selected as having lethal toxic encephalopathy. There were 1295 children with shigellosis during the 10 years of the study. Five children (0.4%) had lethal toxic encephalopathy due to shigellosis. Death occurred following rapid neurological detoriation resulting in brain edema despite intensive treatment. Evidence of brain edema may be a prediction factor for death. Early recognition of encephalopathy and measures to prevent brain edema may improve patient outcome.