Fourth down and five.

Binocular diplopia and right hemifacial numbness developed in a 52-year-old woman after resection of a right temporal lobe glioblastoma. Based on the Parks-Bielschowsky 3-step test, she was diagnosed with a right cranial nerve (CN) IV palsy in addition to right CN V dysfunction. Iatrogenic diplopia may result from temporal lobe surgery due to the intimate relationship of CN IV and CN III to the mesial temporal lobe. In addition, injury to CN V within Meckel cave is believed to be the cause of facial numbness in some patients after temporal lobe surgery. The anatomy of the intracranial portion of CN IV is reviewed, and the etiologies of CN IV palsy are discussed.

A novel WDR45 mutation in a patient with ß-propeller protein-associated neurodegeneration.

Neurodegeneration with brain iron accumulation (NBIA) is a group of genetic diseases characterized by progressive extrapyramidal symptoms and focal iron accumulation in the basal ganglia. ß-Propeller protein-associated neurodegeneration (BPAN), also known as static encephalopathy of childhood with neurodegeneration in adulthood or NBIA 5, is an X-linked dominant subtype of NBIA.1 Brain MRI studies consistently demonstrate iron accumulation in the globus pallidus and substantia nigra with a subset of patients also demonstrating a halo of hyperintense signal surrounding a thin region of hypointense signal in the substantia nigra on T1-weighted imaging.2 The majority of patients with BPAN are female, but several affected males with identical phenotypes have been described, most likely harboring postzygotic mutations leading to somatic mosaicism.3 BPAN has been shown to be caused by heterozygous mutations in WDR45 at Xp11.23. To date, all mutations have been de novo, with no affected relatives.1,3,4 We report here on a patient with BPAN with a novel c.597_598 deletion mutation in WDR45.

Rapidly Progressive Quadriplegia and Encephalopathy.

A woman aged 77 years was transferred to our neurocritical care unit for evaluation and treatment of rapidly progressive motor weakness and encephalopathy. Examination revealed an ability to follow simple commands only and abnormal movements, including myoclonus, tongue and orofacial dyskinesias, and opsoclonus. Imaging study findings were initially unremarkable, but when repeated, they demonstrated enhancement of the cauda equina nerve roots, trigeminal nerve, and pachymeninges. Cerebrospinal fluid examination revealed mildly elevated white blood cell count and protein levels. Serial electrodiagnostic testing demonstrated a rapidly progressive diffuse sensory motor axonopathy, and electroencephalogram findings progressed from generalized slowing to bilateral periodic lateralized epileptiform discharges. Critical details of her recent history prompted a diagnostic biopsy. Over time, the patient became completely unresponsive with no further abnormal movements and ultimately died. The differential diagnosis, pathological findings, and diagnosis are discussed with a brief review of a well-known yet rare diagnosis.

Human Rabies - Wyoming and Utah, 2015.

In September 2015, a Wyoming woman was admitted to a local hospital with a 5-day history of progressive weakness, ataxia, dysarthria, and dysphagia. Because of respiratory failure, she was transferred to a referral hospital in Utah, where she developed progressive encephalitis. On day 8 of hospitalization, the patient's family told clinicians they recalled that, 1 month before admission, the woman had found a bat on her neck upon waking, but had not sought medical care. The patient's husband subsequently had contacted county invasive species authorities about the incident, but he was not advised to seek health care for evaluation of his wife's risk for rabies. On October 2, CDC confirmed the patient was infected with a rabies virus variant that was enzootic to the silver-haired bat (Lasionycteris noctivagans). The patient died on October 3. Public understanding of rabies risk from bat contact needs to be improved; cooperation among public health and other agencies can aid in referring persons with possible bat exposure for assessment of rabies risk.

An enzyme-coupled continuous spectrophotometric assay for S-adenosylmethionine-dependent methyltransferases.

Modification of small molecules and proteins by methyltransferases affects a wide range of biological processes. Here, we report an enzyme-coupled continuous spectrophotometric assay to quantitatively characterize S-adenosyl-L-methionine (AdoMet/SAM)-dependent methyltransferase activity. In this assay, S-adenosyl-L-homocysteine (AdoHcy/SAH), the transmethylation product of AdoMet-dependent methyltransferases, is hydrolyzed to S-ribosylhomocysteine and adenine by recombinant S-adenosylhomocysteine/5'-methylthioadenosine nucleosidase (SAHN/MTAN, EC 3.2.2.9). Subsequently, adenine generated from AdoHcy is further hydrolyzed to hypoxanthine and ammonia by recombinant adenine deaminase (EC 3.5.4.2). This deamination is associated with a decrease in absorbance at 265 nm that can be monitored continuously. Coupling enzymes are recombinant and easily purified. The utility of this assay was shown using recombinant rat protein arginine N-methyltransferase 1 (PRMT1, EC 2.1.1.125), which catalyzes the mono- and dimethylation of guanidino nitrogens of arginine residues in select proteins. Using this assay, the kinetic parameters of PRMT1 with three synthetic peptides were determined. An advantage of this assay is the destruction of AdoHcy by AdoHcy nucleosidase, which alleviates AdoHcy product feedback inhibition of S-adenosylmethionine-dependent methyltransferases. Finally, this method may be used to assay other enzymes that produce AdoHcy, 5'-methylthioadenosine, or compounds that can be cleaved by AdoHcy nucleosidase.

Synthesis of LuxS inhibitors targeting bacterial cell-cell communication.

[reaction: see text] Quorum sensing is a process by which bacteria sense cell density. This cell-cell communication process is mediated by autoinducers. A cross-species messenger, autoinducer-2 (AI-2) is produced from S-ribosyl-L-homocysteine by the LuxS enzyme. A proposed mechanism for LuxS is an aldose-ketose isomerization of S-ribosylhomocysteine followed by a beta-elimination. We report here the synthesis of two substrate analogues, S-anhydroribosyl-L-homocysteine and S-homoribosyl-L-cysteine, which prevent the initial and final step of the mechanism, respectively.