Mycobacterium avium-avium-Associated Typhlitis Mimicking Appendicitis in an Immunocompetent Host

Mycobacterium avium-intracellulare complex (MAC) primarily causes respiratory infection in patients with underlying lung disease or disseminated disease in immunocompromised patients. We report a unique case of MAC disease in the terminal ileum of a healthy patient, mimicking appendicitis. This case emphasizes the need to further explore MAC pathogenesis in immunocompetent hosts.     

Stability-indicating micellar electrokinetic chromatography method for the analysis of sumatriptan succinate in pharmaceutical formulations

A micellar electrokinetic chromatography method for the determination of sumatriptan succinate in pharmaceutical formulations was developed. The effects of several factors such as pH, surfactant and buffer concentration, applied voltage, capillary temperature, and injection time were investigated. Separation took about 5 min using phenobarbital as internal standard. The separation was carried out in reversed polarity mode at 20 °C, 26 kV and using hydrodynamic injection for 10 s. Separation was achieved using a bare fused-silica capillary 50 μm × 40 cm and background electrolyte of 25 mM sodium dihydrogen phosphate—adjusted with concentrated phosphoric acid to pH 2.2, containing 125 mM sodium dodecyl sulfate and detection was at 226 nm. The method was validated with respect to linearity, limits of detection and quantification, accuracy, precision and selectivity. The calibration curve was linear over the range of 100-2000 μg mL⁻¹. The relative standard deviations of intra-day and inter-day precision for migration time, peak area, corrected peak area, ratio of corrected peak area and ratio of peak area were less than 0.68, 3.48, 3.28, 2.97 and 2.83% and 2.01, 5.50, 4.46, 4.92 and 4.07%, respectively. The proposed method was successfully applied to the determinations of the analyte in tablet. Forced degradation studies were conducted by introducing a sample of sumatriptan succinate standard solution to different forced degradation conditions using neutral (water), basic (0.1 M NaOH), acidic (0.1 M HCl), oxidative (10% H₂O₂) and photolytic (exposure to UV light at 254 nm for 2 h). It is concluded that the stability-indicating method for sumatriptan succinate can be used for the analysis of the drug in various samples.     

Checklist and pictorial key to fourth-instar larvae of mosquitoes (Diptera: Culicidae) of Saudi Arabia

The Kingdom of Saudi Arabia includes fauna from three zoogeographic regions: the Afrotropical, Oriental, and Palaearctic regions. To study the mosquito (Diptera: Culicidae) fauna of these regions in Saudi Arabia, larval collections were made at 15 sites during 2005-2006. Thirty-three species representing nine genera were found. Six species, Anopheles culicifacies Giles s.l., Anopheles subpictus Grassi s.l., Culex arbieeni Salem, Culex simpsoni Theobald, Culex univittatus Theobald, and Ochlerotatus detritus Haliday are reported for the first time for Saudi Arabia. An annotated checklist and an illustrated key to the fourth-instar larvae of the 33 species are presented, along with some remarks about problematic species. Eleven species of genus Anopheles Meigen, five species of tribe Aedini, 13 species of genus Culex L., two species of genus Culiseta Felt, one species of genus Lutzia Theobald, and one species of genus Uranotaenia Lynch Arribátlzaga were recorded during the study.     

Anxiety symptoms and perceived performance in medical students

Medical students represent a highly educated population under significant pressures. During the transition to clinical settings in the third year, they may experience a loss of external control and may counter this with an increase in obsessionality and/or other anxiety symptoms. Our study examines the phenomenology of obsessive-compulsive and other anxiety symptoms in medical students at two U.S. medical schools and relates these symptoms to self-perception of performance. Subjects anonymously completed a battery of questionnaires regarding obsessive-compulsive symptoms, attentional problems, anxiety symptoms, depressive symptoms, and perceived performance in medical school. A factor analysis of obsessional symptoms showed four primary factors: checking/doubts, contamination, long time/detail, and unpleasant thoughts/worries. These four factors were similar to those found among college students and other nonclinical populations. Anxiety, attentional, and depressive symptoms were highest in the third-year medical students. In contrast, obsessional symptoms were highest in the first-year students and lower for subsequent years. Perceived performance was not significantly correlated with obsessionality, although lower perceived performance was associated with higher levels of anxiety and depressive symptoms. Students with lower perceived performance in medical school were significantly more likely to be female, depressed, or older. The progressive decrease in number of obsessional symptoms across years and the lack of correlation with perceived performance suggest that these symptoms may be developmentally appropriate, and perhaps adaptive. In contrast, other anxiety symptoms appear to be maladaptive responses to external stressors.     

Rapid turnover of spinules at synaptic terminals

Spinules found in brain consist of small invaginations of plasma membranes which enclose membrane evaginations from adjacent cells. Here, we focus on the dynamic properties of the most common type, synaptic spinules, which reside in synaptic terminals. In order to test whether depolarization triggers synaptic spinule formation, hippocampal slice cultures (7-day-old rats, 10–14 days in culture) were exposed to high K⁺ for 0.5–5 min, and examined by electron microscopy. Virtually no synaptic spinules were found in control slices representing a basal state, but numerous spinules appeared at both excitatory and inhibitory synapses after treatment with high K⁺. Spinule formation peaked with ∼1 min treatment at 37 °C, decreased with prolonged treatment, and disappeared after 1–2 min of washout in normal medium. The rate of disappearance of spinules was substantially slower at 4 °C. N-methyl-d-aspartic acid (NMDA) treatment also induced synaptic spinule formation, but to a lesser extent than high K⁺ depolarization. In acute brain slices prepared from adult mice, synaptic spinules were abundant immediately after dissection at 4 °C, extremely rare in slices allowed to recover at 28 °C, but frequent after high K⁺ depolarization. High pressure freezing of acute brain slices followed by freeze-substitution demonstrated that synaptic spinules are not induced by chemical fixation. These results indicate that spinules are absent in synapses at low levels of activity, but form and disappear quickly during sustained synaptic activity. The rapid turnover of synaptic spinules may represent an aspect of membrane retrieval during synaptic activity.     

Block-copolymer micelles as carriers of cell signaling modulators for the inhibition of JNK in human islets of Langerhans

Here we investigate the potential of PCL-b-PEO micelles in preventing the cell death of isolated human islets of Langerhans. PCL-b-PEO micelles were loaded with c-Jun NH₂-terminal kinases inhibitor SP600125 to rescue the isolated islets. Mechanistic studies of the uptake were conducted in PC12 cells. Incorporation of SP600125 afforded 8.2 fold greater solubility of SP600125 in micelle suspension. To investigate the effectiveness of micelle-incorporated SP600125 in preventing the islet cell death, we challenged the islets with TNF-alpha, IL-1, and IFN gamma. Micelle-incorporated SP600125 did not lose its inhibitory activity during incorporation into micelles, and it protected the islets against cytokine-induced loss of viability to the same extent as control SP600125. Moreover, the concentration of micelle-incorporated SP600125 used was 13-fold lower, demonstrating the greater efficacy of micelle delivered SP600125. Micelles maintained their cytoplasmic distribution without detectable nuclear localization in islets. The inhibition of JNK was confirmed by western blots. This study suggests that micelle-based intracellular delivery of potent, poorly water soluble, cell-death-pathway inhibitors may represent a valuable addition to established delivery of cytocidal block-copolymer micelle-incorporated bioactives.     

Oxazolone-induced delayed type hypersensitivity reaction in the adult yucatan pigs. A useful model for drug development and validation

The purpose of this study was to establish a model of delayed type hypersensitivity (DTH) reaction in the ear skin of large animals such as adult Yucatan pigs, which may aid in evaluating the efficacy of therapeutic modalities of newly developed anti-inflammatory drugs. The pigs were sensitized with oxazolone, re-challenged with the same irritant six days later, and dosed with either vehicle or with cyclosporine A (CsA) before and after challenge. CsA reduced the redness, inhibited the accumulation of ear fluid and inflammatory cells, as well as the release of the inflammatory mediators. Further, CsA inhibited the proliferation of T cells collected from the spleens or PBMCs of CsA-treated pigs when these cells were stimulated in vitro with PMA plus Ionomycin. These results indicate that pig skin can be used to evaluate modalities for the purpose of developing drugs that may be used to treat DTH in humans.     

Vertical Scar Mammaplasty in Gigantomastia: Retrospective Study of 115 Patients Treated Using the Modified Lejour Technique

Since 1996, the original technique of superior pedicle vertical scar mammaplasty described by Lejour has been modified by decreasing skin and glandular undermining, limiting liposuction, avoiding tight glandular stitches, and adding a small horizontal scar for very large breasts. Between 1996 and 2002, 115 consecutive patients underwent a bilateral reduction mammaplasty of more than 500 g per breast using the modified Lejour technique. The early, late, and delayed complications were studied according to four parameters: glandular resection, age, smoking habits, and body mass index (BMI). There was no difference in terms of complications according to the glandular resection. Patients with a high BMI were found to have a higher rate of wound dehiscence. The occurrence of partial areolar necrosis proved to be related to smoking habits. Patients younger than 20 years presented a lower rate of seroma. The modified Lejour technique has proved to be safe and effective for large breasts.