Alpha-Synuclein Aggregation in Parkinson's Disease.

Parkinson's disease (PD), a neurodegenerative disorder characterized by distinct aging-independent loss of dopaminergic neurons in substantia nigra pars compacta (SNpc) region urging toward neuronal loss. Over the decade, various key findings from clinical perspective to molecular pathogenesis have aided in understanding the genetics with assorted genes related with PD. Subsequently, several pathways have been incriminated in the pathogenesis of PD, involving mitochondrial dysfunction, protein aggregation, and misfolding. On the other hand, the sporadic form of PD cases is found with no genetic linkage, which still remain an unanswered question? The exertion in ascertaining vulnerability factors in PD considering the genetic factors are to be further dissevered in the forthcoming decades with advancement in research studies. One of the major proponents behind the prognosis of PD is the pathogenic transmutation of aberrant alpha-synuclein protein into amyloid fibrillar structures, which actuates neurodegeneration. Alpha-synuclein, transcribed by SNCA gene is a neuroprotein found predominantly in brain. It is implicated in the modulation of synaptic vesicle transport and eventual release of neurotransmitters. Due to genetic mutations and other elusive factors, the alpha-synuclein misfolds into its amyloid form. Therefore, this review aims in briefing the molecular understanding of the alpha-synuclein associated with PD.

Decoding Conformational Imprint of Convoluted Molecular Interactions Between Prenylflavonoids and Aggregated Amyloid-Beta42 Peptide Causing Alzheimer's Disease.

Protein misfolding occurs due to the loss of native protein structure and adopts an abnormal structure, wherein the misfolded proteins accumulate and form aggregates, which result in the formation of amyloid fibrils that are associated with neurodegenerative diseases. Amyloid beta (Aß42) aggregation or amyloidosis is contemplated as a unique hallmark characteristic of Alzheimer's disease (AD). Due to aberrant accrual and aggregation of Aß42 in extracellular space, the formation of senile plaques is found in AD patients. These senile plaques occur usually in the cognitive and memory region of the brain, enfeebles neurodegeneration, hinders the signaling between synapse, and disrupts neuronal functioning. In recent years, herbal compounds are identified and characterized for their potential as Aß42 inhibitors. Thus, understanding their structure and molecular mechanics can provide an incredible finding in AD therapeutics. To describe the structure-based molecular studies in the rational designing of drugs against amyloid fibrils, we examined various herbal compounds that belong to prenylflavonoids. The present study characterizes the trends we identified at molecular docking studies and dynamics simulation where we observed stronger binding orientation of bavachalcone, bavachin, and neobavaisoflavone with the amyloid-beta (Aß42) fibril structure. Hence, we could postulate that these herbal compounds could be potential inhibitors of Aß42 fibrils; these anti-aggregation agents need to be considered in treating AD.

Detection and pharmacokinetics of a cytomegalovirus (CMV) DNA plasmid in human plasma during a clinical trial of an intramuscular CMV vaccine in hematopoietic stem cell transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) causes significant morbidity and mortality in solid organ and bone marrow transplant recipients. DNA vaccines can provide both humoral and cellular immunity without exposing immune-compromised persons to replication-competent CMV. METHODS: We studied the kinetics of CMV vaccine DNA in plasma. The samples were obtained from vaccine recipients who were enrolled in a double-blinded, placebo-controlled clinical trial of an intramuscular, plasmid-based, bivalent DNA vaccine for CMV in stem cell transplant recipients. Residual specimens on patients enrolled in the vaccine trial were saved until the trial was unblinded and published. Quantitative real-time polymerase chain reaction (PCR) was used to detect and quantify CMV glycoprotein B (gB) DNA in plasma from 4 recipients of the vaccine. The melting temperature of the vaccine gB amplicon was 62.4°C, compared to 68.8°C, which is seen with the wild-type virus. RESULTS: Sequence analysis revealed that there were 3 mismatches between the fluorescent resonance energy transfer probe and the vaccine DNA sequence. CONCLUSION: Because preemptive treatment of CMV disease in stem cell transplant patients is based on quantitative PCR analysis of viral sequences in plasma, it is important that vaccine sequences not be confused with those in wild-type virus. Confusion could lead to treatment with toxic medications, potentially compromising the transplant. Effects of PCR target choice and amplicon detection techniques on patient management and vaccine trials are discussed.

Characterization and genotoxicity evaluation of particulate matter collected from industrial atmosphere in Tamil Nadu state, India.

Ambient particulate matter (PM) collected in the vicinity of five industries (Cement, Chemical, Thermal power plant, Sponge-iron and Steel) in Tamil Nadu state, India was characterized for size distribution, metals and polycyclic aromatic hydrocarbons (PAHs) content. Genotoxicity of PM and organic matter (OM) extracted from PM was measured in human lung cancer cell-line, A549 and in human liver carcinoma cell-line, HepG2, respectively, using the comet assay. PM values varied from 57.0 µg/m(3) of air at Cement industry upstream to 561.0 µg/m(3) of air at Sponge iron industry downstream samples. Their metal content varied from 5.758 µg/m(3) of air at Chemical industry to 46.144 µg/m(3) of air at Sponge iron industry and PAH concentration varied from 0.5 ng/m(3) air in upstream Thermal power plant to 3302.4 ng/m(3) air in downstream Sponge iron industry samples. While all PM samples induced DNA strand breaks at higher dose levels, downstream samples of Steel and Sponge iron industries which contained relatively higher concentrations of PAHs and metals and exhibited higher levels of pro-oxidant activity as measured by DTT activity induced significantly higher levels of DNA damage in HepG2 and A549 cells. Pretreatment of A549 cells with vitamin C or quercetin significantly reduced PM induced DNA strand breaks.

Cryptococcal meningitis presenting as sinusitis in a renal transplant recipient.

Cryptococcal meningitis is a relatively common invasive fungal infection in immunocompromised patients, especially in solid organ transplant recipients. Clinical presentation typically includes fever, headache, photophobia, neck stiffness, and/or altered mental status. Unusual presentations may delay diagnosis. Therapy is challenging in renal transplant patients because of the nephrotoxicity associated with amphotericin B, the recommended treatment. We present a case of cryptococcal meningitis in a renal transplant recipient presenting as acute sinusitis with successful treatment using fluconazole as primary therapy.

Vaccination adherence in hematopoietic stem cell transplant patients: a pilot study on the impact of vaccination cards and reminder telephone calls.

BACKGROUND: The Karmanos Cancer Center Bone Marrow Transplant (KCC BMT) Center updated the vaccination protocol for transplant patients based on joint guidelines recently published by European Bone Marrow Transplantation, Centers for Disease Control, Infectious Diseases Society of America, and the American Society for Bone Marrow Transplantation. The objectives for this study were to determine the impact of vaccination cards and telephone outreach on vaccine adherence and to determine the reasons for missed or delayed vaccinations. METHODS: Retrospective analysis consisted of autologous and allogeneic hematopoietic stem cell transplant (HSCT) patients at the KCC BMT Clinic who received vaccines based on the guidelines published in 2009. Adherence was calculated as percentage of vaccines missed over the vaccination period. RESULTS: Overall, 37 of 111 patients (33%) missed at least 1 vaccine set and 29 patients (26%) received 1 set later than recommended. Reasons for missed and delayed vaccines included neutropenia/thrombocytopenia, anticoagulation, active infection, and graft-versus-host complications. CONCLUSIONS: Current guidelines recommend a complex vaccination schedule for the HSCT recipients, which may lead to difficulties with adherence. Our study shows that missed and delayed vaccinations are common in both autologous and allogeneic HSCT recipients. Methods to improve adherence are needed.

In vitro-in vivo correlation of voriconazole resistance due to G448S mutation (cyp51A gene) in Aspergillus fumigatus.

Invasive pulmonary aspergillosis continues to be associated with a high mortality despite timely and appropriate therapy. Although host immunity plays a major role in poor clinical response, antifungal drug resistance cannot be ignored. Our studies were aimed 1) to study the mechanism of drug resistance in voriconazole strains of Aspergillus fumigatus, 2) to establish a causal relationship between cyp51A mutation and voriconazole resistance (VRC-R), and 3) to determine whether VRC-R due to cyp51A mutation correlated with in vivo resistance. A point mutation (G448S) involving cyp51A gene in VRC-R isolate was associated with resistance to VRC but not to posaconazole (POS); POS had superior activity to VRC in reducing lung fungal burden and mortality in mice infected with a VRC-R mutant of A. fumigatus. Our study demonstrated that azole resistance is based on specific site of cyp51A mutation and that in vitro VRC-R correlates with in vivo resistance.

Open surgical repair of abdominal aortic aneurysm: proximal aortic control by endoaortic balloon - a novel approach.

Patients with infrarenal abdominal aortic aneurysm with unfavorable anatomy for endovascular aneurysm repair have to undergo open surgical repair. Open surgery has its own morbidity in terms of proximal clamping and declamping, bleeding and prolonged hospital stay and mortality. We present two such patients with juxtarenal abdominal aortic aneurysm who underwent open surgical repair. The proximal aortic control during open surgical repair of the aneurysm was achieved by endoaortic balloon occlusion technique.

Clinical impact of the use of 16S rRNA sequencing method for the identification of "difficult-to-identify" bacteria in immunocompromised hosts.

Molecular method of 16S rRNA sequencing is reported to be helpful in the accurate identification of organisms with ambiguous phenotypic profiles. We analyzed the use of 16S rRNA sequencing method to identify clinically significant, "difficult-to-identify" bacteria recovered from clinical specimens, and evaluated its role in patient management and consequent clinical outcome. Among the 172 "difficult-to-identify" bacteria recovered over a 4-year period, 140 were gram-positive cocci or gram-negative bacilli; identification by 16S rRNA did not play a role in the management of patients infected with these bacteria. From 32 patients, 33 "difficult-to-identify" gram-positive bacilli were identified; the organisms were mycobacteria, Nocardia, Tsukamurella, Rhodococcus, and Gordonia. In 24 patients for whom clinical data were available, results from the 16S rRNA sequencing method led to treatment change in 14 immunocompromised patients (including 7 hematopoietic stem cell recipients and 1 liver transplant recipient). Therapy was modified in 9 patients, initiated in 3 patients, and discontinued in 2 patients. Most patients' therapy was switched to oral antibiotics with discontinuation of intravascular catheters, facilitating early hospital discharge. All 14 patients were alive 30 days after infection onset. The present study demonstrates the clinical application of 16S rRNA sequencing method to identify "difficult-to-identify" mycobacteria and other gram-positive bacilli in clinical specimens, particularly in immunocompromised hosts.

Weissella confusa: an unexpected cause of vancomycin-resistant gram-positive bacteremia in immunocompromised hosts.

We report the first case of Weissella confusa bacteremia in an allogeneic hematopoietic stem cell transplant patient. After engraftment and discharge, the patient returned with fever and graft failure and was started on an empiric regimen of aztreonam and vancomycin. A blood culture grew an alpha-hemolytic, gram-positive coccus forming pairs and chains, originally thought to be a viridans Streptococcus and a skin contaminant. The isolation of the organism from multiple blood cultures, and the presence of vancomycin resistance prompted identification and additional susceptibility testing. The RapID(™) Str panel, which has W. confusa in its database, provided multiple incorrect identifications. The MicroScan WalkAway 96 SI, using PC-20 or -29 panels, also did not identify this bacterium, because it is not in their database. The organism was identified as W. confusa by 16S rDNA sequencing. Antibiotic susceptibility determination by Etest revealed vancomycin resistance and daptomycin susceptibility. Therapy was changed to daptomycin, and the infection resolved. Additionally, W. confusa sepsis, with multiple positive blood cultures, developed in a patient in the burn unit at our medical center. The patient's blood cultures remained positive until vancomycin was discontinued and daptomycin therapy initiated. Infections with vancomycin-resistant, gram-positive cocci are emerging among immuno compromised hosts. Under appropriate circumstances, clinicians need to request that the laboratory perform susceptibility testing and accurate identification, by nucleic acid sequencing if necessary. Sequencing of 16S rDNA is an important tool in the accurate identification of unusual pathogens.

Listeria grayi: vancomycin-resistant, gram-positive rod causing bacteremia in a stem cell transplant recipient.

We report the first case of Listeria grayi bacteremia in a stem cell transplant recipient. The patient developed bacteremia with a gram-positive rod that was initially thought to be Corynebacterium species and a skin contaminant. The organism grew in multiple blood cultures and therapy with vancomycin was initiated. The API Coryne (version 3.0) identified the organism as L. grayi. Susceptibility testing by Etest suggested that the organism was resistant to vancomycin, but susceptible to ampicillin. After therapeutic change from vancomycin to ampicillin, the bacteremia cleared. Empiric therapy with vancomycin for all gram-positive bacterial infections is not appropriate. Accurate identification and antibiotic susceptibility is important, particularly in those with persistent bacteremia.

In vitro interaction of posaconazole with calcineurin inhibitors and sirolimus against zygomycetes.

OBJECTIVES: Zygomycosis is an uncommon but devastating disease with few therapeutic options. Calcineurin inhibitors and sirolimus (mTOR inhibitor), commonly used in transplant patients as immunosuppressives, have antifungal activity. They are known to demonstrate synergy with triazoles against certain fungi, though limited data exist about their activity against zygomycetes. Our aim was to study the in vitro interaction of posaconazole with calcineurin inhibitors and sirolimus against zygomycetes. METHODS: Drug interactions were assessed with chequerboard dilution for posaconazole with calcineurin inhibitors and sirolimus according to the CLSI M38-A2 method for filamentous fungi. Twenty-eight clinical isolates were studied, including Rhizopus arrhizus, Rhizopus microsporus, Rhizomucor pusillus, Mucor sp., Cunninghamella bertholletiae, Myocladus corymbifera and Apophysomyces elegans. Combinations of posaconazole with tacrolimus, cyclosporin A or sirolimus were used. Experiments were performed in duplicate. Mean fractional inhibitory concentration indices were calculated. RESULTS: Posaconazole with calcineurin inhibitors demonstrated consistent synergy against C. bertholletiae, M. corymbifera and A. elegans, whereas synergy or no interaction was primarily observed against R. arrhizus, R. microsporus, R. pusillus and Mucor. Antagonism was seen with the combination of posaconazole and sirolimus. Strain variability was noted among the same species. CONCLUSIONS: The clinical significance of these findings is unclear, but further studies are warranted given the potential for concomitant use of these agents in transplant patients treated for zygomycosis.

Rhodococcus equi lung infection in an allogeneic hematopoietic stem cell transplant recipient.

In this report, we describe a case of Rhodococcus equi lung infection diagnosed in an allogeneic hematopoietic stem cell transplant with oral graft-versus-host disease 3 months after stem cell infusion. The lung lesion persisted despite an approximate 3 months of vancomycin therapy, but then responded favorably to a combination of intravenous ertapenem at 1 g daily and oral rifampin at 600 mg daily for 1 month. An overview of Rhodococcus infection in transplant recipients is presented. This case and the discussed literature suggest that combination antibiotic therapy is warranted in patients with decreased humoral and cellular immunity.

Non-bacterial infections in allogeneic non-myeloablative stem cell transplant recipients.

Data on non-bacterial infections during allogeneic non-myeloablative hematopoietic stem cell transplantation (HSCT) are widely different. We evaluated data on 48 consecutive patients who received a conditioning regimen with fludarabine and cyclophosphamide (73%) or fludarabine and total body irradiation (27%) and then underwent allogeneic non-myeloablative HSCT. Cytomegalovirus (CMV) infection was common and occurred in 48% of patients; 3 patients developed CMV disease, and all survived. CMV reactivation was found to be common with both conditioning regimens in our patient population. Invasive aspergillosis occurred in 4 patients (8%) and 3 died. Other serious non-bacterial infections were uncommon. Review of the available literature on non-myeloablative HSCT suggests that the frequency and type of opportunistic infections vary considerably.