Size of submicrometric and nanometric particles affect cellular uptake and biological activity of macrophages in vitro.

BACKGROUND: Micrometric and nanometric particles are increasingly used in different fields and may exhibit variable toxicity levels depending on their physicochemical characteristics. The aim of this study was to determine the impact of the size parameter on cellular uptake and biological activity, working with well-characterized fluorescent particles. We focused our attention on macrophages, the main target cells of the respiratory system responsible for the phagocytosis of the particles. METHODS: FITC fluorescent silica particles of variable submicronic sizes (850, 500, 250 and 150 nm) but with similar surface coating (COOH) were tailored and physico-chemically characterized. These particles were then incubated with the RAW 264.7 macrophage cell line. After microscopic observations (SEM, TEM, confocal), a quantitative evaluation of the uptake was carried out. Fluorescence detected after a quenching with trypan blue allows us to distinguish and quantify entirely engulfed fluorescent particles from those just adhering to the cell membrane. Finally, these data were compared to the in vitro toxicity assessed in terms of cell damage, inflammation and oxidative stress (evaluated by LDH release, TNF-α and ROS production respectively). RESULTS AND CONCLUSION: Particles were well characterized (fluorescence, size distribution, zeta potential, agglomeration and surface groups) and easily visualized after cellular uptake using confocal and electron microscopy. The number of internalized particles was precisely evaluated. Size was found to be an important parameter regarding particles uptake and in vitro toxicity but this latter strongly depends on the particles doses employed.

In vitro radiosensitizing effects of ultrasmall gadolinium based particles on tumour cells.

Since radiotherapy is widely used in cancer treatment, it is essential to develop strategies which lower the irradiation burden while increasing efficacy and become efficient even in radio resistant tumors. Our new strategy is relying on the development of solid hybrid nanoparticles based on rare-earth such as gadolinium. In this paper, we then evidenced that gadolinium-based particles can be designed to enter efficiently into the human glioblastoma cell line U87 in quantities that can be tuned by modifying the incubation conditions. These sub-5 nm particles consist in a core of gadolinium oxide, a shell of polysiloxane and are functionalized by diethylenetriaminepentaacetic acid (DTPA). Although photoelectric effect is maximal in the [10-100 keV] range, such particles were found to possess efficient in-vitro radiosensitizing properties at an energy of 660 keV by using the "single-cell gel electrophoresis comet assay," an assay that measures the number of DNA damage that occurs during irradiation. Even more interesting, the particles have been evidenced by MTT assays to be also efficient radiosensitizers at an energy of 6 MeV for doses comprised between 2 and 8 Gy. The properties of the gadolinium-based particles give promising opening to a particle-assisted radio-therapy by using irradiation systems already installed in the majority of hospitals.

Evaluating SPIO-labelled cell MR efficiency by three-dimensional quantitative T2* MRI.

An in vitro MR-assay for superparamagnetic iron oxide (SPIO) particle cell labelling assessment via three-dimensional quantitative T(2) (*) MR microscopy was proposed. On high-resolution images, and due to the high susceptibility difference between the particles and the surrounding medium, SPIO internalized in cells induces signal loss which may be counted and measured on T(2) (*) maps. The increase in both labelled cell percentage and the average perturbation volume with an added amount of iron in the incubation medium proved that intracellular iron uptake is dependent upon the initial concentration of incubation iron. It also proved that the observed increases in total cellular iron uptake measured by inductively coupled plasma optical emission spectroscopy are due to both an increase in the iron mass per cell and also an increase in labelled cell concentration. MR results were compared with Prussian blue staining histology. The sensitivity of the MR methodology was then used to distinguish labelling differences for two different types of particle coating. The MRI-assay we proposed is a compulsory tool to optimize labelling efficiency in order to improve in vivo cell detection. Key parameters for detection, such as the percentage of cell labelling, the effect on the image for a given amount of internalized iron and labelling distribution among a cell population, are easily obtained. The comparison of different contrast agents for labelling one cell type, the assessment of one type of contrast agent for labelling different cell types and/or the evaluation of labelling strategies, are possible without having recourse to classical methods, and provide improved accuracy, since the principle is based on intracellular relaxivity.

The knowledge and attitudes of surgical staff towards the use of opioids in cancer pain management: can the Hospital Palliative Care Team make a difference?

The principles of cancer pain management are well established, but evidence suggests that these are not incorporated into daily practice and patients are still in pain. Deficiencies in knowledge and inappropriate attitudes towards the use of opioids may partially explain why the management of cancer pain is still such a widespread problem. This study assessed the knowledge and attitudes of 135 nursing and medical staff working in a surgical unit, before and after working with a newly established Hospital Palliative Care Team. The baseline survey highlighted the existence of a number of myths and misconceptions in relation to opioid use. Results of the follow-up survey indicated that the knowledge and attitudes of doctors and nurses had improved after working with the team, but that this probably occurred as a result of good working relationships and case discussions rather than through formal teaching. The study provided a useful method of identifying deficiencies in knowledge and attitude among staff, and helped to raise awareness of the problem of cancer pain management. Our challenge now is to work with staff to ensure that positive changes in knowledge and attitudes are translated into the everyday practice of hospital nurses and doctors caring for patients with cancer.

Surges of increased T cell reactivity to an encephalitogenic region of myelin proteolipid protein occur more often in patients with multiple sclerosis than in healthy subjects.

We have previously shown that patients with multiple sclerosis (MS) have increased T cell responses to the immunodominant region (residues 184-209) of myelin proteolipid protein (PLP). The present study investigated whether this reactivity fluctuates over time and correlates with disease activity. We performed monthly limiting dilution assays for 12-16 mo in four healthy subjects and five patients with relapsing-remitting MS to quantify the frequencies of circulating T cells proliferating in response to PLP(41-58), PLP(184-199), PLP(190-209), myelin basic protein (MBP), MBP(82-100), and tetanus toxoid. Disease activity was monitored by clinical assessment and gadolinium-enhanced magnetic resonance imaging of the brain. There were fluctuations in the frequencies of autoreactive T cells in all subjects. Compared with healthy controls, MS patients had significantly more frequent surges of T cells reactive to the 184-209 region of PLP, but infrequent surges of T cell reactivity to MBP(82-100). There was temporal clustering of the surges of T cell reactivity to MBP(82-100) and MBP, suggesting T cell activation by environmental stimuli. Some clinical relapses were preceded by surges of T cell reactivity to PLP(184-209), and in one patient there was significant correlation between the frequency of T cells reactive to PLP(184-199) and the total number of gadolinium-enhancing magnetic resonance imaging lesions. However, other relapses were not associated with surges of T cell reactivity to the Ags tested. T cells reactive to PLP(184-209) may contribute to the development of some of the CNS lesions in MS.

Transoral resection of retro-odontoid disc sequestration: case report and review of the literature.

A rare case of retro-odontoid disc sequestration causing significant cord compression and progressive neurological deterioration is presented. The clinical history, radiology, treatment and pathogenesis of the case are described, along with a review of the relevant literature.

Deep cerebral venous thrombosis presenting as an encephalitic illness.

Three cases of deep cerebral vein thrombosis presenting as encephalitic illnesses are described. Thyrotoxicosis was present in one case, ulcerative colitis in one case and an anticardiolipin antibody was detected in two cases. All three patients were on oestrogen and progesterone. Magnetic resonance imaging and angiography allowed rapid confirmation of the diagnosis and permitted non-invasive follow up of this condition. The first two patients made complete clinical recoveries despite having thalamic infarction, in one case bilaterally, demonstrable radiologically.

Bronchiolitis obliterans organising pneumonia: a clinical and radiological review.

BACKGROUND: The clinical presentation, course, and radiological spectrum of bronchiolitis obliterans organising pneumonia (BOOP) is still being characterised to aid differentiation from other causes of organising pneumonia. AIMS: To define the clinical presentation, response to therapy, and radiological spectrum of BOOP. METHODS: Fifteen cases of BOOP were retrospectively reviewed. The clinical presenting features, treatment and outcome of each patient were determined. Three independent readers and chest X-rays (CXRs) were blinded. CXRs were scored by a semi-quantitative method. Modal scores were calculated for type and profusion of opacification of each CXR. RESULTS: The mean age of presentation was 64 years and the median duration of follow-up was 12.5 months. Thirteen patients received corticosteroid therapy. Outcome was varied. One patient had progressive loss of lung function, five had persisting symptoms with stable abnormal lung function, and nine were asymptomatic with near normal lung function. Five patients had a disease relapse. Symptoms length prior to presentation, duration and intensity of treatment were not associated with outcome (p = 0.23-0.9). Radiological opacities were alveolar in 73%, large localised infiltrates in 13%, nodular in 20% and mobile in 33% of CXR series. There was no relationship between overall profusion, type of CXR opacities and patient outcome, treatment duration or treatment intensity (p = 0.42-1.0). CONCLUSIONS: The clinical spectrum of BOOP includes mild subacute, chronic progressive, and acute life threatening illness. Prognosis and response to treatment is variable. The diversity of radiological findings and clinical presentations should prompt consideration of the diagnosis in patients with undiagnosed respiratory tract symptoms and persisting or varying radiological abnormalities.

A report of actinomycosis involving the lung and liver.

A case is presented of actinomycosis that involved the lung and the liver, which was diagnosed after a computed-tomographic-guided needle biopsy of a liver mass. The diagnosis was made on histological grounds that were based on the staining and morphological characteristics of Actinomyces spp. Imaging techniques suggested a communication between the lung and liver lesions. The regression of the disease was followed during 12 months of therapy. The patient remained free of disease for three months after the cessation of treatment. The relevant literature is reviewed.

Computed tomographic appearances and clinical features of prolactin-secreting pituitary adenomas in young male patients.

Prolactin-secreting adenomas, the commonest of the pituitary tumours, are being recognised with increasing frequency in men. Their appearance and behaviour differ from those occurring in women, being typically larger and more aggressive. We describe the clinical features and radiological findings of three prolactinomas in young males and review the literature.

An evaluation of dynamic pituitary function tests in patients with pituitary tumours.

In a prospective study of 26 patients with macroadenoma of the pituitary (14 secretory and 12 non-secretory), basal and stimulated pituitary hormone levels were used to detect hypothalamic dysfunction and to examine pituitary hormone secretion before and after hypophysectomy. Suprasellar tumour extention with hypothalamic compression occurred in 18 patients but was not consistently associated with hormonal tests indicative of hypothalamic dysfunction. In patients with secretory tumours, secretory activity was adequately assessed by basal hormone levels alone, which showed that surgery reduced hormone levels by a mean 85% in acromegaly and by a mean 55% in prolactinomas. Preoperatively, pituitary reserve of hormones not being hypersecreted was often normal, despite large tumour size and hypothalamic compression. Even after apparently complete pituitary removal at surgery, normal responses to stimulatory tests could sometimes be detected. Conventional dynamic tests are only of limited value in the assessment of hypothalamo-pituitary dysfunction in patients with large pituitary tumours and should not be used indiscriminately in such individuals requiring surgery.