Mechanism of the reduced elimination clearance of benzylpenicillin from cerebrospinal fluid in rats with intracisternal administration of lipopolysaccharide.

The mechanism responsible for the reduced clearance of benzylpenicillin (BPC) from the cerebrospinal fluid (CSF) was investigated in rats that received an intracisternal administration of lipopolysaccharide (LPS). BPC was intraventricularly injected and its elimination from the CSF studied. During the inflammation created by the LPS administration to the cisterna magna, the clearance of BPC and taurine from the CSF was significantly reduced but reverted to the control level when N-nitro-L-arginine, a nitric oxide (NO) synthase inhibitor, was intracisternally administered. The in vitro uptake of BPC and taurine was significantly reduced in the choroid plexus (CP, the blood-CSF barrier) of rats with experimental inflammation and in control CP that had been pretreated with sodium nitroprusside (SNP, an NO donor). Interestingly, the clearance and CP uptake of formycin B, a substrate for a nucleoside transporter, were not affected by the experimental inflammation or by pretreatement with SNP. These observations suggest that the BPC transporter, and probably other transport systems as well, is functionally sensitive to NO in the blood-CSF barrier. Therefore, functional impairment of BPC transport in the CP by NO may be partly responsible for the increase in BPC concentration in the CSF during inflammation such as that caused by meningitis.     

Skull Base Invasion of Adenoid Cystic Carcinoma of the Lacrimal Gland : A Case Report

Although adenoid cystic carcinoma (ACC) of the lacrimal gland is a rarely encountered orbital tumor, it invades intracranially more frequently than carcinomas of other glands in the head and neck. A 52-year-old man underwent orbital exenteration and resection of intracranially extended tumor via a fronto-orbito-zygomatic approach in combination with a transfacial approach. Histopathologically, the tumor showed perineural, vascular, and lymphatic invasion. Additionally, he received radiotherapy (60 Gy) and adjuvant systemic cisplatin and 5-fluorouracil chemotherapy due to residual tumor in the orbit and systemic metastases (lung, ribs, and spines). He was free of progression and recurrence at 6 months after treatment. The authors report a case of skull base invasion by an ACC of the lacrimal gland to remind neurosurgeons planning intervention that this disease shows a tendency to invade intracranially.     

The steroid effect on the blood-ocular barrier change induced by triolein emulsion as seen on contrast-enhanced MR images.

OBJECTIVE: The purpose of this study is to evaluate the effect of dexamethasone on the damaged blood-ocular barrier caused by triolein emulsion, using contrast-enhanced MR imaging. MATERIALS AND METHODS: An emulsion of 0.1-mL triolein in 20 mL of saline was infused into the carotid arteries of 32 cats, 12 cats were placed in the treatment group and 18 cats were placed in the Control group. Thirty minutes after the infusion of triolein emulsion, a set of orbital pre- and post-contrast T1-weighted MR images (T1WIs) were obtained. Infusion of 10 mg/kg dexamethasone into the ipsilateral carotid artery of each of the cats in the treatment group cats and 20 mL saline in each of the cats in the control group was given. A second set of pre- and post-contrast orbital T1WIs were obtained three hours following triolein emulsion infusion. Qualitative analysis was performed for the the anterior chamber (AC), the posterior chamber (PC), and in the vitreous humor of the ipsilateral and contralateral eyes. The signal intensity ratios of the ipsilateral eye over the contralateral eye were quantitatively evaluated in the three ocular chambers on the first and second set of T1WIs, and were then statistically compared. RESULTS: Qualitatively, the AC, the PC or the vitreous did not show immediate contrast enhancement on the first and the second set of post-contrast T1WIs. However, the AC and the PC showed delayed contrast enhancement for both groups of cats on the second pre-contrast T1WIs. No enhancement or minimally delayed enhancement was seen for the vitreous humor. Quantitatively, the signal intensity ratios in the PC of the treatment group of cats were statistically lower than the ratios of the control group of cats for the second set of T1WIs (p = 0.037). The AC and vitreous showed no statistically significant difference between the feline treatment group and control group (p > 0.05). CONCLUSION: Contrast-enhanced MR images revealed increased vascular permeability in the PC of the eye after infusion of triolein emulsion. Dexamethasone seems to decrease the breakdown of the blood-aqueous barrier in the PC.     

Erratum: MRI monitoring of focal cerebral ischemia in peroxisome proliferator‐activated receptor (PPAR)‐deficient mice

NMR In Biomedicine: MRI monitoring of focal cerebral ischemia in peroxisome proliferator‐activated receptor (PPAR)‐deficient mice. Jean‐Baptiste Pialat, Tae‐Hee Chao, Olivier Beuf, Elisabeth Joye, Samir Moucharaffie, Jean‐Baptiste Langlois, Chantal Nemoz, Marc Janier, Yves Berthezene, Norbert Nighoghossian, Béatrice Desvergnre and Marlene Wiart. Published online April 24 2007, Issue 20:3, pp. 335–342; DOI: 10.1002/nbm.1157 . Following publication it has been noted that an author's name was misspelt. As above, the author was spelt as “Samir Moucharaffie”. It should have been spelt as “Samir Moucharrafie”.     

Immersion ultrasonography of excised nonpalpable breast lesion specimens after ultrasound-guided needle localization

OBJECTIVE: Ultrasound-guided needle localization has been used prior to the surgical excision of nonpalpable breast lesions. The aim of the study was to assess the feasibility of the use of a saline immersion specimen ultrasound technique (immersion-US) to confirm the successful removal of breast lesions. MATERIALS AND METHODS: The devised immersion-US technique was used to examine the excised tissues of 72 ultrasound-guided needle localized breast lesions of 58 patients (34 benign lesions, 30 high-risk lesions and 8 malignant lesions). Freshly excised specimens were placed in a container filled with saline and one radiologist scanned the surgically excised specimens using a high-frequency linear transducer. We evaluated successful lesion removal and the qualities of the immersion-US images. Miss rates were determined by the use of postoperative ultrasound during follow-up. RESULTS: All 72 lesions were identified by the use of immersion-US and satisfactory or excellent quality images were obtained for most lesions (70/72, 97%). Five (7%) lesions were initially identified as incompletely excised, based on the immersion-US findings, and prompt re-excision was undertaken. Follow-up ultrasound examinations showed no residual mass in the surgical field in any patient. CONCLUSION: The immersion-US technique was found straightforward and efficient to perform. Immersion-US was able to determine whether nonpalpable breast lesions had been successfully excised after ultrasound-guided needle localization.     

Impact of oxidative stress on lung diseases

Reactive oxygen species (ROS) are products of normal cellular metabolism and are known to act as second messengers. Under physiological conditions, ROS participate in maintenance of cellular 'redox homeostasis' in order to protect cells against oxidative stress through various redox-regulatory mechanisms. Overproduction of ROS, most frequently due to excessive stimulation of either reduced nicotinamide adenine dinucleotide phosphate by cytokines or the mitochondrial electron transport chain and xanthine oxidase, results in oxidative stress. Oxidative stress is a deleterious process that leads to lung damage and consequently to various disease states. Knowledge of the mechanisms of ROS regulation could lead to the pharmacological manipulation of antioxidants in lung inflammation and injury.