Size-dependent toxicity of silver nanoparticles to Glyptotendipes tokunagai

OBJECTIVES: This study aims to evaluate the size-dependent toxicity of spherical silver nanoparticles (Ag NPs) to an endemic benthic organism, Glyptotendipes tokunagai. METHODS: Ag nanoparticles of three nominal sizes (50, 100, and 150 nm) capped with polyvinyl pyrrolidone (PVP-Ag NPs) were used. Their physicochemical properties, acute toxicity (48 hours), and bioaccumulation were measured using third instar larvae of G. tokunagai. RESULTS: The aggregation and dissolution of PVP-Ag NPs increased with exposure time and concentration, respectively, particularly for 50 nm PVP-Ag NPs. However, the dissolved concentration of Ag ions was not significant compared with the median lethal concentration value for AgNO3 (3.51 mg/L). The acute toxicity of PVP-Ag NPs was highest for the smallest particles (50 nm), whereas bioaccumulation was greatest for the largest particles (150 nm). However, larger PVP-Ag NPs were absorbed and excreted rapidly, resulting in shorter stays in G. tokunagai than the smaller ones. CONCLUSIONS: The size of PVP-Ag NPs significantly affects their acute toxicity to G. tokunagai. In particular, smaller PVP-Ag NPs have a higher solubility and stay longer in the body of G. tokunagai, resulting in higher toxicity than larger PVP-Ag NPs.

Size-dependent toxicity of silver nanoparticles to Glyptotendipes tokunagai

OBJECTIVES: This study aims to evaluate the size-dependent toxicity of spherical silver nanoparticles (Ag NPs) to an endemic benthic organism, Glyptotendipes tokunagai. METHODS: Ag nanoparticles of three nominal sizes (50, 100, and 150 nm) capped with polyvinyl pyrrolidone (PVP-Ag NPs) were used. Their physicochemical properties, acute toxicity (48 hours), and bioaccumulation were measured using third instar larvae of G. tokunagai. RESULTS: The aggregation and dissolution of PVP-Ag NPs increased with exposure time and concentration, respectively, particularly for 50 nm PVP-Ag NPs. However, the dissolved concentration of Ag ions was not significant compared with the median lethal concentration value for AgNO3 (3.51 mg/L). The acute toxicity of PVP-Ag NPs was highest for the smallest particles (50 nm), whereas bioaccumulation was greatest for the largest particles (150 nm). However, larger PVP-Ag NPs were absorbed and excreted rapidly, resulting in shorter stays in G. tokunagai than the smaller ones. CONCLUSIONS: The size of PVP-Ag NPs significantly affects their acute toxicity to G. tokunagai. In particular, smaller PVP-Ag NPs have a higher solubility and stay longer in the body of G. tokunagai, resulting in higher toxicity than larger PVP-Ag NPs.

Cervico-thoraco-lumbar Spinal Epidural Abscess and Psoas Abscess Successfully Treated with Parenteral Antibiotic Therapy and Percutaneous Drainage: A Case Report

We describe a 75-year-old man with a cervico-thoraco-lumbar spinal epidural abscess was extended to the psoas muscle. The patient complained high fever and back pain, followed by weakness of the lower extremities. He had received multiple epidural injections in a local pain clinic just few days before the onset of fever. The multi-segmental epidural abscess which was demonstrated by MRI compressed dural sac and cord. The best way to recommend him was to undergo a surgical decompression, but he refused the surgery. Next, we chose nonsurgical treatment such as longstanding parenteral antibiotic therapy and percutaneous drainage of psoas abscess. We could cultivate a causative organism and chose appropriate antibiotics. The patient experienced immediate relief of fever and the improvement of laboratory findings, gradual relief of back pain and full neurological recovery.

A Morphometric Analysis of the Foramen Ovale and the Zygomatic Points Determined by a Computed Tomography in Patients with Idiopathic Trigeminal Neuralgia

OBJECTIVE: The purpose of this study is to measure the dimensions of foramen ovale and to localize the zygomatic point using computed tomography(CT) in Korean adults with idiopathic trigeminal neuralgia. METHODS: Facial axial CT scans using the orbitomeatal plane were performed in 67patients (39males and 28females; mean age 58.8years) with idiopathic classic trigeminal neuralgia. We measured the size of the foramen ovale and localized the zygomatic point which was a skin marker over the ipsilateral zygoma that approximates the lateral projection of a straight line joining the centers of the two foramen ovale. RESULTS: The axial dimensions of the foramen ovale on the orbitomeatal plane were of average length: 8.18+/-0.82mm (range 6.9~11.5mm), width: 4.06+/-0.86mm (2.5~5.7mm). The average distance between the external acoustic meatus and the zygomatic point was 21.64+/-1.99mm (16.3~25.0mm) and the average distance of anterior margin of condylar process of mandible to zygomatic point was 4.29+/-1.19mm (1.0~7.0mm). CONCLUSION: The anatomical understandings including the size of the foramen ovale and localization of the zygomatic point could be helpful in determining a plan of percutaneous approaches to foramen ovale.

Clinical Analysis of Operation for Elderly Patients with Cerebral Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE: The number of elderly patients with cerebral aneurysm has markedly increased. We investigate the clinical characteristics and the surgical outcomes of cerebral aneurysms of elderly patients aged over 65 years comparing with those of control group aged under 65 years. METHODS: Total 439 patients were done aneurysm surgery between January 1998 to December 2002. The clinical data of 78 old-aged patients and 361 control group patients were reviewed to assess the relationship between sex, Hunt-Hess grade at admission, Fisher's grade at admission, site of aneurysm, timing of surgery, vasospasm, hydrocephalus, surgical outcome and age. RESULTS: The proportion of female, poor Hunt-Hess grade, poor Fisher's grade and hydrocephalus were significantly higher in old-aged patients than those of control group. But aneurysmal site and the rate of vasospasm were not different significantly in these two groups. Favorable outcomes were 75.6% for control group patients and 67.9% for old-aged patients. The surgical outcome was not statistic significantly different between two groups. The main causes of unfavorable outcome among elderly patients were attributed to their poorer Hunt-Hess grades on admission and postoperative medical complications. CONCLUSION: We conclude that old age is not a contra-indication for aneurysm surgery for elderly patients. And also after surgery, aggressive treatment and prevention of medical complications can lead to a better outcome.

Pseudotumor Cerebri Associated with Polycythemia Vera

We report a case of pseudotumor cerebri associated with hematologic disorder, polycythemia vera. The patient was 35 years old woman and experienced headache and nausea for three months. She presented bilateral papilledema with visual field defect. On MRI investigation no intracranial abnomality were observed except empty sella syndrome. Lumbar puncture showed increased intracranial pressure and normal biology. Hematologic study showed elevated hemoglobin and hematocrit level. The patient was treated with therapeutic lumbar puncture and acetazolamide. Repeated phlebotomy was done for treatment of polycythemia vera, and symptoms resolved gradually.