scholarly journals Brain-Eating Amoebae: Predilection Sites in the Brain and Disease Outcome

2017 ◽  
Vol 55 (7) ◽  
pp. 1989-1997 ◽  
Author(s):  
Timothy Yu Yee Ong ◽  
Naveed Ahmed Khan ◽  
Ruqaiyyah Siddiqui
Keyword(s):  
Case Reports ◽  
Treatment Options ◽  
Acute Infection ◽  
Content Type ◽  
Disease Outcomes ◽  
Granulomatous Amoebic Encephalitis ◽  
Causative Agents ◽  
Diagnostic Modalities ◽  
Amoebic Meningoencephalitis ◽  
The Brain

ABSTRACTAcanthamoebaspp. andBalamuthia mandrillarisare causative agents of granulomatous amoebic encephalitis (GAE), whileNaegleria fowlericauses primary amoebic meningoencephalitis (PAM). PAM is an acute infection that lasts a few days, while GAE is a chronic to subacute infection that can last up to several months. Here, we present a literature review of 86 case reports from 1968 to 2016, in order to explore the affinity of these amoebae for particular sites of the brain, diagnostic modalities, treatment options, and disease outcomes in a comparative manner.

scholarly journals Naegleria fowleri: Pathogenesis, Diagnosis, and Treatment Options

2015 ◽  
Vol 59 (11) ◽  
pp. 6677-6681 ◽  
Author(s):  
Eddie Grace ◽  
Scott Asbill ◽  
Kris Virga
Keyword(s):  
Case Reports ◽  
Treatment Options ◽  
Clinical Manifestations ◽  
Naegleria Fowleri ◽  
Content Type ◽  
High Profile ◽  
Free Living Amoeba ◽  
Nægleria Fowleri ◽  
Amoebic Meningoencephalitis

ABSTRACTNaegleria fowlerihas generated tremendous media attention over the last 5 years due to several high-profile cases. Several of these cases were followed very closely by the general public.N. fowleriis a eukaryotic, free-living amoeba belonging to the phylum Percolozoa.Naegleriaamoebae are ubiquitous in the environment, being found in soil and bodies of freshwater, and feed on bacteria found in those locations. WhileN. fowleriinfection appears to be quite rare compared to other diseases, the clinical manifestations of primary amoebic meningoencephalitis are devastating and nearly always fatal. Due to the rarity ofN. fowleriinfections in humans, there are no clinical trials to date that assess the efficacy of one treatment regimen over another. Most of the information regarding medication efficacy is based on either case reports orin vitrostudies. This review will discuss the pathogenesis, diagnosis, pharmacotherapy, and prevention ofN. fowleriinfections in humans, including a brief review of all survivor cases in North America.

scholarly journals Efficacy of Guanabenz Combination Therapy against Chronic Toxoplasmosis across Multiple Mouse Strains

2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Jennifer Martynowicz ◽  
J. Stone Doggett ◽  
William J. Sullivan
Keyword(s):  
Limit Of Detection ◽  
Acute Infection ◽  
Antagonistic Effect ◽  
Mouse Strains ◽  
Chronic Infections ◽  
Content Type ◽  
Brain Cyst ◽  
The Brain

ABSTRACT Toxoplasma gondii, an obligate intracellular parasite that can cause life-threatening acute disease, differentiates into a quiescent cyst stage to establish lifelong chronic infections in animal hosts, including humans. This tissue cyst reservoir, which can reactivate into an acute infection, is currently refractory to clinically available therapeutics. Recently, we and others have discovered drugs capable of significantly reducing the brain cyst burden in latently infected mice, but not to undetectable levels. In this study, we examined the use of novel combination therapies possessing multiple mechanisms of action in mouse models of latent toxoplasmosis. Our drug regimens included combinations of pyrimethamine, clindamycin, guanabenz, and endochin-like quinolones (ELQs) and were administered to two different mouse strains in an attempt to eradicate brain tissue cysts. We observed mouse strain-dependent effects with these drug treatments: pyrimethamine-guanabenz showed synergistic efficacy in C57BL/6 mice yet did not improve upon guanabenz monotherapy in BALB/c mice. Contrary to promising in vitro results demonstrating toxicity to bradyzoites, we observed an antagonistic effect between guanabenz and ELQ-334 in vivo. While we were unable to completely eliminate the brain cyst burden, we found that a combination treatment with ELQ-334 and pyrimethamine impressively reduced the brain cyst burden by 95% in C57BL/6 mice, which approached the limit of detection. These analyses highlight the importance of evaluating anti-infective drugs in multiple mouse strains and will help inform further preclinical studies of cocktail therapies designed to treat chronic toxoplasmosis.

scholarly journals Pseudomonas aeruginosa Contact-Dependent Growth Inhibition Plays Dual Role in Host-Pathogen Interactions

mSphere ◽  
2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Jeffrey A. Melvin ◽  
Jordan R. Gaston ◽  
Shawn N. Phillips ◽  
Michael J. Springer ◽  
Christopher W. Marshall ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acute Infection ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Microbial Pathogenesis ◽  
Host Pathogen Interactions ◽  
Gram Negative ◽  
Content Type ◽  
Disease Outcomes ◽  
Host Pathogen

ABSTRACT How bacteria compete and communicate with each other is an increasingly recognized aspect of microbial pathogenesis with a major impact on disease outcomes. Gram-negative bacteria have recently been shown to employ a contact-dependent toxin-antitoxin system to achieve both competition and regulation of their physiology. Here, we show that this system is vital for virulence in acute infection as well as for establishment of chronic infection in the multidrug-resistant pathogen Pseudomonas aeruginosa. Greater understanding of the mechanisms underlying bacterial virulence and infection is important for the development of effective therapeutics in the era of increasing antimicrobial resistance. Microorganisms exist in a diverse ecosystem and have evolved many different mechanisms for sensing and influencing the polymicrobial environment around them, utilizing both diffusible and contact-dependent signals. Contact-dependent growth inhibition (CDI) is one such communication system employed by Gram-negative bacteria. In addition to CDI mediation of growth inhibition, recent studies have demonstrated CDI-mediated control of communal behaviors such as biofilm formation. We postulated that CDI may therefore play an active role in host-pathogen interactions, allowing invading strains to establish themselves at polymicrobial mucosal interfaces through competitive interactions while simultaneously facilitating pathogenic capabilities via CDI-mediated signaling. Here, we show that Pseudomonas aeruginosa produces two CDI systems capable of mediating competition under conditions of growth on a surface or in liquid. Furthermore, we demonstrated a novel role for these systems in contributing to virulence in acute infection models, likely via posttranscriptional regulation of beneficial behaviors. While we did not observe any role for the P. aeruginosa CDI systems in biofilm biogenesis, we did identify for the first time robust CDI-mediated competition during interaction with a mammalian host using a model of chronic respiratory tract infection, as well as evidence that CDI expression is maintained in chronic lung infections. These findings reveal a previously unappreciated role for CDI in host-pathogen interactions and emphasize their importance during infection. IMPORTANCE How bacteria compete and communicate with each other is an increasingly recognized aspect of microbial pathogenesis with a major impact on disease outcomes. Gram-negative bacteria have recently been shown to employ a contact-dependent toxin-antitoxin system to achieve both competition and regulation of their physiology. Here, we show that this system is vital for virulence in acute infection as well as for establishment of chronic infection in the multidrug-resistant pathogen Pseudomonas aeruginosa. Greater understanding of the mechanisms underlying bacterial virulence and infection is important for the development of effective therapeutics in the era of increasing antimicrobial resistance.

scholarly journals Primary Amoebic Meningoencephalitis by Naegleria fowleri: Pathogenesis and Treatments

Biomolecules ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1320 ◽  
Author(s):  
Andrea Güémez ◽  
Elisa García
Keyword(s):  
Molecular Mechanisms ◽  
Case Reports ◽  
Naegleria Fowleri ◽  
Initial Exposure ◽  
Immunomodulatory Agents ◽  
Primary Amoebic Meningoencephalitis ◽  
The Central Nervous System ◽  
Nægleria Fowleri ◽  
Amoebic Meningoencephalitis ◽  
The Brain

Naegleria fowleri is a free-living amoeba (FLA) that is commonly known as the “brain-eating amoeba.” This parasite can invade the central nervous system (CNS), causing an acute and fulminating infection known as primary amoebic meningoencephalitis (PAM). Even though PAM is characterized by low morbidity, it has shown a mortality rate of 98%, usually causing death in less than two weeks after the initial exposure. This review summarizes the most recent information about N. fowleri, its pathogenic molecular mechanisms, and the neuropathological processes implicated. Additionally, this review includes the main therapeutic strategies described in case reports and preclinical studies, including the possible use of immunomodulatory agents to decrease neurological damage.

Primary central nervous system T-cell lymphoma

1991 ◽  
Vol 74 (4) ◽  
pp. 668-672 ◽  
Author(s):  
Martin M. Bednar ◽  
Anthony Salerni ◽  
Martin E. Flanagan ◽  
William W. Pendlebury
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
T Cell ◽  
Cell Lymphoma ◽  
Case Reports ◽  
Treatment Options ◽  
T Cell Lymphoma ◽  
Content Type ◽  
Diagnostic Measures ◽  
T Cell Lymphomas

✓ Primary central nervous system (CNS) T-cell lymphoma is extremely rare. The present case report provides immunocytochemical evidence for a cerebellar CNS T-cell lymphoma. The patient underwent surgery followed by radiation therapy and is alive and well 36 months postoperatively. The clinical and pathological features of primary CNS T-cell lymphoma as well as diagnostic measures and treatment options are discussed, together with a compilation of all previous case reports of primary CNS T-cell lymphomas.

scholarly journals Treatment of Infections by OXA-48-Producing Enterobacteriaceae

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Adam Stewart ◽  
Patrick Harris ◽  
Andrew Henderson ◽  
David Paterson
Keyword(s):  
Antimicrobial Agents ◽  
Case Reports ◽  
Treatment Options ◽  
Treatment Success ◽  
Intrinsic Activity ◽  
Beta Lactamase ◽  
Global Public Health ◽  
Content Type ◽  
Extended Spectrum Beta Lactamase

ABSTRACT Carbapenemase-producing Enterobacteriaceae (CPE) contribute significantly to the global public health threat of antimicrobial resistance. OXA-48 and its variants are unique carbapenemases with low-level hydrolytic activity toward carbapenems but no intrinsic activity against expanded-spectrum cephalosporins. blaOXA-48 is typically located on a plasmid but may also be integrated chromosomally, and this gene has progressively disseminated throughout Europe and the Middle East. Despite the inability of OXA-48-like carbapenemases to hydrolyze expanded-spectrum cephalosporins, pooled isolates demonstrate high variable resistance to ceftazidime and cefepime, likely representing high rates of extended-spectrum beta-lactamase (ESBL) coproduction. In vitro data from pooled studies suggest that avibactam is the most potent beta-lactamase inhibitor when combined with ceftazidime, cefepime, aztreonam, meropenem, or imipenem. Resistance to novel avibactam combinations such as imipenem-avibactam or aztreonam-avibactam has not yet been reported in OXA-48 producers, although only a few clinical isolates have been tested. Although combination therapy is thought to improve the chances of clinical cure and survival in CPE infection, successful outcomes were seen in ∼70% of patients with infections caused by OXA-48-producing Enterobacteriaceae treated with ceftazidime-avibactam monotherapy. A carbapenem in combination with either amikacin or colistin has achieved treatment success in a few case reports. Uncertainty remains regarding the best treatment options and strategies for managing these infections. Newly available antibiotics such as ceftazidime-avibactam show promise; however, recent reports of resistance are concerning. Newer choices of antimicrobial agents will likely be required to combat this problem.

Severe Head Injury linked to Subsequent Development of Malignant Brain Tumour within a Short Period- A Case Report

2018 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Head Injury ◽  
Brain Tumour ◽  
Severe Head Injury ◽  
Case Reports ◽  
Subsequent Development ◽  
Malignant Brain Tumour ◽  
Tumour Development ◽  
Short Period ◽  
The Brain

There have been a few case reports of head injury leading to brain tumour development in the same region as the brain injury. Here we report a case where the patient suffered a severe head injury with contusion. He recovered clinically with conservative management. Follow up Computed Tomography scan of the brain a month later showed complete resolution of the lesion. He subsequently developed malignant brain tumour in the same region as the original contusion within a very short period of 15 months. Head injury patients need close follow up especially when severe. The link between severity of head injury and malignant brain tumour development needs further evaluation. Role of anti-inflammatory agents for prevention of post traumatic brain tumours needs further exploration.

Long-term management of patients with multiple brain metastases after shaped beam radiosurgery

2004 ◽  
pp. 406-412
Author(s):  
Paul Okunieff ◽  
Michael C. Schell ◽  
Russell Ruo ◽  
E. Ronald Hale ◽  
Walter G. O'Dell ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Tumor Control ◽  
Content Type ◽  
Negative Results ◽  
Multiple Metastases ◽  
Extracranial Disease ◽  
Successful Control ◽  
The Brain

✓ The role of radiosurgery in the treatment of patients with advanced-stage metastatic disease is currently under debate. Previous randomized studies have not consistently supported the use of radiosurgery to treat patients with numbers of brain metastases. In negative-results studies, however, intracranial tumor control was high but extracranial disease progressed; thus, patient survival was not greatly affected, although neurocognitive function was generally maintained until death. Because the future promises improved systemic (extracranial) therapy, the successful control of brain disease is that much more crucial. Thus, for selected patients with multiple metastases to the brain who remain in good neurological condition, aggressive lesion-targeting radiosurgery should be very useful. Although a major limitation to success of this therapy is the lack of control of extracranial disease in most patients, it is clear that well-designed, aggressive treatment substantially decreases the progression of brain metastases and also improves neurocognitive survival. The authors present the management and a methodology for rational treatment of a patient with breast cancer who has harbored 24 brain metastases during a 3-year period.

Radiosurgery for patients with recurrent small cell lung carcinoma metastatic to the brain: outcomes and prognostic factors

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 247-254 ◽  
Author(s):  
Jason Sheehan ◽  
Douglas Kondziolka ◽  
John Flickinger ◽  
L. Dade Lunsford
Keyword(s):  
Lung Cancer ◽  
Brain Metastases ◽  
Lung Carcinoma ◽  
Small Cell Lung Carcinoma ◽  
Small Cell ◽  
Small Cell Lung ◽  
Cell Lung Carcinoma ◽  
Content Type ◽  
The Brain ◽  
Fine Print

Object. Lung carcinoma is the leading cause of death from cancer. More than 50% of those with small cell lung cancer develop a brain metastasis. Corticosteroid agents, radiotherapy, and resection have been the mainstays of treatment. Nonetheless, median survival for patients with small cell lung carcinoma metastasis is approximately 4 to 5 months after cranial irradiation. In this study the authors examine the efficacy of gamma knife surgery for treating recurrent small cell lung carcinoma metastases to the brain following tumor growth in patients who have previously undergone radiation therapy, and they evaluate factors affecting survival. Methods. A retrospective review of 27 patients (47 recurrent small cell lung cancer brain metastases) undergoing radiosurgery was performed. Clinical and radiographic data obtained during a 14-year treatment period were collected. Multivariate analysis was utilized to determine significant prognostic factors influencing survival. The overall median survival was 18 months after the diagnosis of brain metastases. In multivariate analysis, factors significantly affecting survival included: 1) tumor volume (p = 0.0042); 2) preoperative Karnofsky Performance Scale score (p = 0.0035); and 3) time between initial lung cancer diagnosis and development of brain metastasis (p = 0.0127). Postradiosurgical imaging of the brain metastases revealed that 62% decreased, 19% remained stable, and 19% eventually increased in size. One patient later underwent a craniotomy and tumor resection for a tumor refractory to radiosurgery and radiation therapy. In three patients new brain metastases were demonstrating on follow-up imaging. Conclusions. Stereotactic radiosurgery for recurrent small cell lung carcinoma metastases provided effective local tumor control in the majority of patients. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including radiosurgery can extend survival.

scholarly journals Characteristics and Treatment Challenges of Non-Clear Cell Renal Cell Carcinoma

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3807
Author(s):  
Pierangela Sepe ◽  
Arianna Ottini ◽  
Chiara Carlotta Pircher ◽  
Andrea Franza ◽  
Melanie Claps ◽  
...  
Keyword(s):  
Renal Cell ◽  
Kinase Inhibitors ◽  
Clear Cell ◽  
Case Reports ◽  
Treatment Options ◽  
Single Agent ◽  
Growth Factor Receptor ◽  
Mtor Inhibitors ◽  
Cell Renal Cell Carcinoma ◽  
Clear Cell Rcc

Non-clear cell renal cell carcinomas (RCC) comprise several rare and poorly described diseases, often characterized by bad prognosis and with no standard treatments available. The gap in their clinical management is linked to the poor molecular characterization in handling the treatment of non clear-cell RCC with untailored therapies. Due to their rarity, non-clear RCC are in fact under-represented in prospective randomized trials. Thus, treatment choices are based on extrapolating results from clear cell RCC trials, retrospective data, or case reports. Over the last two decades, various options have been considered as the mainstay for the treatment of metastatic RCC (mRCC), including angiogenesis inhibitors, vascular endothelial growth factor receptor inhibitors, other tyrosine kinase inhibitors (TKIs), as well as MET inhibitors and mammalian targeting of rapamycin (mTOR) inhibitors. More recently, the therapeutic armamentarium has been enriched with immunotherapy, alone or in combination with targeted agents that have been shown to significantly improve outcomes of mRCC patients, if compared to TKI single-agent. It has been widely proven that non-clear cell RCC is a morphologically and clinically distinct entity from its clear cell counterpart but more knowledge about its biology is certainly needed. Histology-specific collaborative trials are in fact now emerging to investigate different treatments for non-clear cell RCC. This review summarizes pathogenetic mechanisms of non-clear cell RCC, the evolution of treatment paradigms over the last few decades, with a focus on immunotherapy-based trials, and future potential treatment options.

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