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We report a 53-year-old woman with a rare ruptured lumbar intraspinal epidermoid cyst causing chemical meningitis evaluated with MRI (including diffusion-weighted imaging), with histopathologic correlation.

We present a case of a 35 year-old male with Blastomyces dermatitidis meningitis as the primary presentation of blastomycosis infection, without evidence of involvement outside the CNS at time of discharge. We focus on the magnetic resonance imaging findings, with histopathologic correlation.

Cancers appear to escape surveillance by the immune system at least in part because they fail to induce a protective immune response. Therapeutic vaccines based on specific tumour antigens and tumour cells modified ex vivo by genetic techniques are but two strategies being used to circumvent this problem. In this report, we describe a simple, yet effective alternative in which tumour-specific responses are induced by in situ administration of a well-characterized liposomal formulation of the cytokine interleukin 2 (IL-2). Using the non-immunogenic B16 melanoma model, intratumoural injections of liposomal IL-2 L(IL2), were shown to induce a long-lived immune response specific for the injected tumour. In conjunction with subsequent removal of the primary tumours by surgery, the injections increased mean survival to 57 days from a control value of 32 days and partially protected surviving mice against re-challenge with B16. L(IL2) induced an early infiltration of inflammatory cells within the tumours which was followed several days later by an influx of CD3+ T cells. The cellular influx and a coincident decrease in tumour growth were noted in both injected tumours and a second non-injected tumour on the same animal, thereby demonstrating the systemic nature of the immune response. Intratumoural injections of soluble IL-2 at the same dose failed to induce B16-specific cellular immunity or to prolong survival of the mice. Thus, liposomal formulation of the cytokine was fundamental to successful induction of immunity by this in situ vaccination regimen.

A liposomal Muc1 mucin vaccine for treatment of adenocarcinomas was formulated by incorporating a synthetic Muc1 mucin-based lipopeptide and Lipid A into a DPPC/cholesterol bilayer. Vaccination of mice with the liposomal formulation produced a peptide-specific immune response dependent on the cholesterol content. The response occurred at a threshold of 20–23 mol% cholesterol, and was optimal at cholesterol levels of ≥30 mol%. To understand this cholesterol dependency, we studied the effect of cholesterol on the liposomal bilayer and surface properties. Freeze-fracture electron microscopy showed a unique surface texture that was codependent upon cholesterol (≥20 mol%) and lipopeptide content. Fluorescence anisotropy measurements exhibited a significant decrease in the rotational motion of 1,6-diphenyl-1,3,5-hexatriene in formulations containing >20 mol% cholesterol and only in the presence of the lipopeptide. At 20 mol% cholesterol and with lipopeptide, DSC showed a significant increase in the main phase transition of the DPPC bilayers, while Raman spectroscopy indicated a more ordered arrangement of DPPC molecules compared to control liposomes containing DPPC/cholesterol alone. Taken together, the data suggest the presence of lipopeptide-rich microdomains at and above a threshold of 20 mol% cholesterol that may play a role in the induction of a peptide-specific immunological response.

Oncolipin is a multilamellar liposomal (dimyristoyl phosphatidylcholine) formulation of interleukin 2 (IL-2) and human serum albumin (HSA) with distinct surface characteristics which may influence its biological activities. IL-2 and HSA were detected on the surface of the liposomes using specific antibody staining. Surface expression of IL-2 was also demonstrated by the observation that Oncolipin bound to cells expressing IL-2 receptors (IL-2R) containing alphabetagamma or betagamma subunits. Binding and internalization of Oncolipin by cells expressing alphabetagamma or betagamma receptor subunits was blocked by excess free IL-2 or a neutralizing antibody against the beta chain. The display of surface IL-2 on Oncolipin's liposomes was maintained in vivo after intravenous injection into mice. IL-2 was also present between the lipid bilayers of the multilamellar liposomes based on the unique physical characteristics detected by freeze fracture electron microscopy. The bulk of the liposome-associated IL-2 was released from the liposomes upon incubation at 37 degrees C in medium containing serum, indicating that the IL-2 was not irreversibly entrapped on or in the liposome structure. Thus, Oncolipin is receptor-targeted to activated T and NK cells by virtue of its surface expression of IL-2 and has the potential to release IL-2 following deposition within lymphoid organs. These properties may confer distinct advantages over soluble IL-2 for immunotherapy of cancer and viral diseases.

© 2007 Elsevier 0196-4399/00 (see frontmatter) 173 Introduction Micrococcus species are grampositive cocci (GPC) that are most frequently recovered in blood cultures as phlebotomy-associated contaminants. However, they can be opportunistic pathogens on rare occasions. Our case highlights a previously reported association between Micrococcus spp. and catheter infections in patients with pulmonary arterial hypertension (PAH) who are being treated with epoprostenol (EPO) via central venous catheter (CVC). To enhance prompt recognition of clinically significant culture results, such cases benefit from good communication between the microbiology laboratory and the clinical team.

In this study, a circulation system was used to measure T(1) values of bovine blood under physiological conditions at field strengths of 4.7, 7 and 9.4 T. Results show that T(1) increases linearly with magnetic field B(0) and can be described with the equation T(1)=129 ms/T B(0)+1167 ms for magnetic field strengths between 1.5 and 9.4 T.

When interacting with phospholipid in an aqueous environment, amphotericin B forms unusual structures of markedly reduced toxicity (Janoff et al. (1988) Proc. Natl. Acad. Sci. USA 85, 6122-6126). These structures, which appear ribbon-like by freeze-fracture electron microscopy (EM), are found exclusively at amphotericin B to lipid mole ratios of 1:3 to 1:1. At lower mole ratios they occur in combination with liposomes. Circular dichroism (CD) spectra revealed two distinct modes of lipid-amphotericin B interaction, one for liposomes and one for the ribbon-like structures. In isolated liposomes, amphotericin B which comprised 3-4 mole percent of the bulk lipid was monomeric and exhibited a hemolytic activity comparable to amphotericin B suspended in deoxycholate. Above 3-4 mole percent amphotericin B, ribbon-like structures emerged and CD spectra indicated drug-lipid complexation. Minimal inhibitory concentrations for Candida albicans of liposomal and complexed amphotericin B were comparable and could be attributed to amphotericin a release as a result of lipid breakdown within the ribbon-like material by a heat labile extracellular yeast product (lipase). Negative stain EM of the ribbon-like structures indicated that the ribbon-like appearance seen by freeze-fracture EM arises as a consequence of the cross-fracturing of what are aggregated, collapsed single lamellar, presumably interdigitated, membranes. Studies examining complexation of amphotericin B with either DMPC or DMPG demonstrated that headgroup interactions played little role in the formation of the ribbon-like structures. With these results we propose that ribbon-like structures result from phase separation of amphotericin B-phospholipid complexes within the phospholipid matrix such that amphotericin B release, and thus acute toxicity, is curtailed. Formation of amphotericin B-lipid structures such as those described here indicates a possible new role for lipid as a stabilizing matrix for drug delivery of lipophilic substances, specifically where a highly ordered packing arrangement between lipid and compound can be achieved.

Purpose The radiology externship program at the authors' institution introduces medical students to radiology using a hands-on approach and is tailored to interested third-year medical students. There are currently limited data available on whether the program increases exposure to radiology in a positive fashion and how it influences medical students' education and career choices. Methods In September 2010, current and former externs between 2007 and 2010 were surveyed using an anonymous, Web-based survey. Results The response rates were 100% (11 of 11) for current externs and 52% (15 of 29) for former externs, for an overall response rate of 65% (26 of 40). The respondents included 20 men and 5 women. The average age of respondents was 27.3 ± 2.5 years. Forty-six percent of former externs (6 of 13) had matched to radiology residencies, whereas the remainder had matched to various surgical and nonsurgical subspecialties. Eighty-four percent (21 of 25) had overall positive ratings of the program. Ninety-two percent (23 of 25) felt they had a better understanding of which test was most appropriate to order for common indications, and 88% (22 of 25) felt that they had a better understanding of imaging contraindications. Sixty-eight percent (17 of 25) felt that they had a better understanding of risk-benefit analysis involving imaging using ionizing radiation, and 56% (14 of 25) felt more confident in discussing these matters with their patients. Conclusions This radiology externship program increases exposure to radiology in a positive fashion, increases understanding of the appropriate use of imaging modalities and their associated clinical benefits and risks, and influences medical students' career choices. These results add to the evidence that this type of program is mutually beneficial to medical students, residents, and clinical colleagues and suggest that more medical schools and radiology departments should evaluate the feasibility of starting radiology externship programs.

This report describes the properties of a novel sustained-release drug delivery system comprising liposomes sequestered in a collagen gel. Two peptide hormones, insulin and growth hormone encapsulated in vesicles sequestered within the matrix, are slowly released into the circulation from either an intramuscular or subcutaneous injection site. A maximum 3-5-d release for insulin or a 14-d growth hormone release was observed. Enhanced sequestration of liposomes with the collagen can be achieved by modifying the liposome surface with fibronectin. The liposome gel delivery system appears to offer several advantages over other liposome formulations or gel formulations constructed only with free drug.