In vitro screening of metal oxide nanoparticles for effects on neural function using cortical networks on microelectrode arrays

Nanoparticles (NPs) may translocate to the brain following inhalation or oral exposures, yet higher throughput methods to screen NPs for potential neurotoxicity are lacking. The present study examined effects of 5 CeO₂ (5– 1288?nm), and 4 TiO₂ (6–142?nm) NPs and microparticles (MP) on network function in primary cultures of rat cortex on 12 well microelectrode array (MEA) plates. Particles were without cytotoxicity at concentrations ≤50?µg/ml. After recording 1?h of baseline activity prior to particle (3–50?µg/ml) exposure, changes in the total number of spikes (TS) and # of active electrodes (#AEs) were assessed 1, 24, and 48?h later. Following the 48?h recording, the response to a challenge with the GABA_A antagonist bicuculline (BIC; 25?µM) was assessed. In all, particles effects were subtle, but 69?nm CeO₂ and 25?nm TiO₂ NPs caused concentration-related decreases in TS following 1?h exposure. At 48?h, 5 and 69?nm CeO₂ and 25 and 31?nm TiO₂ decreased #AE, while the two MPs increased #AEs. Following BIC, only 31?nm TiO₂ produced concentration-related decreases in #AEs, while 1288?nm CeO₂ caused concentration-related increases in both TS and #AE. The results indicate that some metal oxide particles cause subtle concentration-related changes in spontaneous and/or GABA_A receptor-mediated neuronal activity in vitro at times when cytotoxicity is absent, and that MEAs can be used to screen and prioritize nanoparticles for neurotoxicity hazard.     

Student attitude towards communication skills learning in a Caribbean medical school

Background

Medical student attitudes towards communication skills are important for curriculum planners and teachers. Xavier University School of Medicine (XUSOM) is a private medical school admitting students mainly from the United States and Canada.

Aims

Attitude of students towards communication skills has not been previously studied in the institution. Hence the present study was carried out.

Method

The study was carried out among the first, second, third and fourth semester undergraduate medical (MD) students at XUSOM, Aruba during July 2013 using the communication skills attitude scale (CSAS). Respondents’ age, gender, nationality, occupation of parents, place of residence of family, semester of study were noted. The positive and negative attitude scale scores were calculated and compared among different subgroups of respondents (p<0.05).

Results

Fifty-one of the seventy-three students (69.9 per cent) participated. The majority were between 20 to 25 years of age, of American nationality, from metro cities and had excellent or good self-perceived verbal and written communication skills. The mean positive attitude scale (PAS) score was 47.65 (maximum being 65) and the mean negative attitude scale (NAS) score was 31.06 (maximum 65). PAS score was significantly higher among respondents whose fathers were not in health related professions. NAS scores were significantly lower among the third and fourth semester respondents.

Conclusion

Students overall had a positive attitude towards communication skills but negative attitudes were also noted Based on results of the study and a review of literature we are planning to start communication skills learning in the institution right from the first semester and students will be provided opportunities for supervised practice during early clinical exposure, hospital observership and with standardised patients. The medical humanities module will be expanded and communication skills learning will continue during the clinical years with higher order skills being taught.     

A superficial ulnar artery anastomosing with a larger anterior interosseous artery to supply the wrist and hand

The term superficial ulnar artery (SUA) is applied to an artery which arises from the axillary, brachial or superficial brachial arteries and courses over the origins of the superficial forearm muscles to join at the midlevel of the forearm with the ulnar artery, sometimes replacing it (Wankoff, 1962; Lippert & Pabst, 1985; Nakatani et al. 1996, 1997). Its incidence ranges from 0.7% (Adachi, 1928) to 3.3% (Müller, 1903). The SUA has been reported with different terminologies; arteria antebrachialis superficialis ulnaris (Gruber, 1867; Müller, 1903; Adachi, 1928), high origin of the ulnar artery (Rodriguez-Baeza et al. 1995; Aharinejad et al. 1997) and SUA with a high origin (Fuss, 1988).
The present observation adds several aspects to the anatomical variations of the superficial ulnar arteries already described, most notably its anastomosis with the anterior interosseous artery. This anastomosis has previously been reported twice (Quain, 1844; Gruber, 1867) but without explanation as to the course taken by the anastomotic branch. The SUA was found in the right arm of a 66-y-old male during routine dissections in the Unit of Anatomy and Embryology at the Autonomous University of Barcelona.     

Human thrombopoietin levels are high when thrombocytopenia is due to megakaryocyte deficiency and low when due to increased platelet destruction

Thrombopoietin (TPO), the ligand for c-mpl, stimulates proliferation of committed megakaryocytic progenitors and induces maturation of megakaryocytes. To better understand factors regulating TPO levels, we measured blood levels of TPO in patients with impaired platelet production due to aplastic anemia (AA) and with platelet destructive disorders, including idiopathic thrombocytopenic purpura (ITP), posttransfusion purpura (PTP), drug purpura (DP), and X-linked thrombocytopenia (XLTP). The TPO receptor capture enzyme immunoassay (EIA) used had a detection limit of integral of approximately-150 to 200 pg/mL. TPO was undetectable in 88 of 89 normal individuals. Eighteen of 19 patients with AA and a mean platelet count (MPC) of 18,000/microliters (2,000 to 61,000/microliters) had markedly elevated TPO levels (mean, 1,467 pg/mL; range, 597 to 3,834 pg/mL). Eight AA patients who responded to immunosuppressive therapy with their MPC increasing to 140,000/microliters (92,000 to 175,000/microliters) had substantial decreases in TPO (mean, 440 pg/mL; range, 193 to 771 pg/mL). Initial TPO levels did not differ significantly between responders and nonresponders. In contrast, all 21 patients with ITP and an MPC of 16,000/microliters (1,000 to 51,000 /microliters) had undetectable TPO levels, as did 6 patients with acute PTP or DP and 2 patients with XLTP. Megakaryocyte mass, reflected in the rate of platelet production, appears to be the major determinant of TPO levels in thrombocytopenic patients rather than circulating platelet levels per se. Measurement of serum TPO may be useful in differentiating thrombocytopenias due to peripheral destruction from those due to thrombopoietic failure.     

Contrast medium-induced adverse reactions: economic outcome

Because the cost of managing an expected greater number of adverse reactions when high-osmolality contrast media (HOM) are used could offset the higher material cost of low-osmolality contrast media (LOM), a prospective study was done of 795 inpatients undergoing any of four procedures involving intravascular injection of HOM: cardiac catheterization, peripheral angiography, head computed tomography (CT), or body CT. The resources used in managing HOM-induced adverse reactions were measured, and the costs of these resources were estimated. Four hundred five patients (51%) had adverse reactions. Reactions were grouped into three classes according to their severity. Class 1 (mild) reactions occurred in 358 patients (45%), class 2 (moderate) reactions occurred in 44 patients (6%), and class 3 (severe) reactions occurred in three patients (0.4%). Ninety-nine patients (12%) consumed resources as a result of an adverse reaction. The average cost of these resources per patient undergoing examination was $1.07 to the radiology department, $5.83 to the hospital, and $12.93 to a charge-paying insurer. Mean (+/- standard deviation) cost to the hospital for managing class 1, class 2, and class 3 reactions were $2.52 +/- $5.33, $24 +/- $54, and $910 +/- $749, respectively. By comparison, the difference in material cost of HOM versus LOM ranged from $93 for body CT to $179 for cardiac catheterization. Even if LOM were to induce no adverse reactions, the increased material cost associated with universal substitution of LOM for HOM would be greater than the expected cost of managing adverse reactions when HOM are used.