Relative pharmacokinetics of three amikacin brands in onco-hemotologic pediatric patients experiencing febrile neutropeina.

Three commercially available brands of amikacin were investigated in a parallel study design for the assessment of comparative pharmacokinetics in pediatric oncology patients with chemotherapy-induced neutropenic febrile episode. Amikacin concentration in serum samples was determined by fluorescence polarization immunoassay method using Abbott TDx system. Computer software, PK II was used for computation of pharmacokinetic parameters of amikacin. The serum concentration of all brands nonsignificantly (p > 0.05) varied at all time points, except at 1 and 2 hrs post dosing. At 1 hr post dosing, the serum concentration of brand II varied from rest of two brands. Whereas at 2 hr following I/V infusion, brands II and I were statistically different. Highest serum concentration of 38.69 +/- 1.45 microg/ml was observed in case of brand III while brands I and II showed lower but not significantly different serum concentration values, i.e., 36.30 +/- 1.65 and 37.89 +/- 1.32 microg/ml, respectively when compared with brand I. The other pharmacokinetic parameters of 3 brands found to have non-significant difference (P < 0.05) except, t(1/2)alpha and Cl of brands I and II that deviated statistically significant (p < 0.01). The relative bioavailability of brand II and III as compared with brand I, considered as standard 86.17 and 96.86%, respectively falls within the accepted limits of +/- 20% required for the bioequivalence of any two brands. Based upon findings of the present study, all these brands may be used interchangeably in oncology patients. Further studies, however are needed to determine whether the statistically elevated Cl value in brand II is of any clinical significance.     

Supraventricular arrhythmia: A complication of 5-fluorouracil therapy

5-Fluorouracil is an S-phase-specific, synthetic pyrimidine antimetabolite, which is used as a cytostatic agent for a variety of malignant lesions, either singly or in multidrug regimens. Gastrointestinal toxicity and myelosuppression are the most common adverse reactions, but, of late, clinical cardiotoxicity has been reported in both prospective and retrospective studies. We present our experience of clinical cardiotoxicity in five patients.     

Vestibular schwannoma growth rates in neurofibromatosis type 2 natural history consortium subjects.

OBJECTIVE: To determine the amount of growth in vestibular schwannomas in Neurofibromatosis type 2 (NF2) patients from diagnosis through short-term (up to 2 yr) and long-term (up to 4 yr) follow-up. STUDY DESIGN: Retrospective magnetic resonance imaging (MRI) films were obtained on subjects enrolled in the NF2 Natural History study and examined for changes in vestibular schwannoma size over time. SETTING: Data were collected from nine foreign and domestic NF2 centers, including hospital-based, academic, and tertiary care centers. SUBJECTS: NF2 patients with MRI data and at least one follow-up examination within 9 months to 2 years of diagnosis were included; n=56 patients with 84 lesions for evaluation of growth. INTERVENTION: Routine, clinically obtained, magnetic resonance images were digitized and measured using image management software. Short-term follow-up was defined as up to 2 years (n=84 lesions), and long-term follow-up was defined as 3 to 4 years (n=29 lesions). OUTCOME MEASURES: Vestibular schwannoma size was assessed using anterior-posterior, medial-lateral, and greatest diameter linear measurements. RESULTS: Vestibular schwannomas increased in size (at least 5 mm) in 8% of the vestibular schwannomas across short-term follow-up. At long-term follow-up, 13% of the tumors had increased in size. On average, schwannomas increased in greatest diameter 1.3 mm per year across short-term follow-up. CONCLUSION: Slightly greater than 1 in 10 diagnosed NF2-related vestibular schwannomas increased in size by at least 5 mm by 4 years of follow-up, if still untreated at that time.     

Interspeaker variation in habitual speaking rate: additional evidence.

PURPOSE: The purpose of the present study was to test the hypothesis that talkers previously classified by Y.-C. Tsao and G. Weismer (1997) as habitually fast versus habitually slow would show differences in the way they manipulated articulation rate across the rate continuum. METHOD: Thirty talkers previously classified by Tsao and Weismer (1997) as having habitually slow (n = 15; 7 males, 8 females) and habitually fast (n = 15; 8 males, 7 females) articulation rates produced a single sentence at 7 different rates, using a magnitude production paradigm. Hence, the participants were not randomly assigned to conditions. RESULTS: Quadratic regression functions relating measured to intended articulation rates were all statistically significant, and most important, there were significant differences between the slow and fast groups in the y intercepts of the functions, for both males and females. CONCLUSIONS: This study provides a constructive replication of Tsao and Weismer (1997), showing a difference between slow and fast talkers with a new set of speech materials and in a new task. The findings appear to be consistent with a biological basis for intertalker rate differences.     

Evaluation of cytotoxic, oxidative stress, proinflammatory and genotoxic responses of micro- and nano-particles of dolomite on human lung epithelial cells A(549)

Dolomite is a natural mineral of great industrial importance and used worldwide, thus millions of workers are at risk of occupational exposure. Its toxicity is however, meagerly documented. In the present investigation, a dolomite powder obtained from its milling unit was analyzed by some standard methods namely, optical microscopy, transmission electron microscopy and dynamic light scattering. Results showed that dolomite powder contained particles of different shapes and size both microparticles (MPs) and nanoparticles (NPs), suggesting potential occupational exposure of these particles. An attempt was therefore, made to investigate dolomite toxicity in a particle size-dependent manner in human lung epithelial cells A(549). The comparative toxicity evaluation of MPs and NPs was carried out by assessing their effects on cell viability, membrane damage, glutathione, reactive oxygen species (ROS), lipid peroxidation (LPO), micronucleus (MN) and proinflammatory cytokines, namely tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). These markers of cytotoxicity, genotoxicity and inflammation were assayed in cells exposed to MPs and NPs in a dose-and time-dependent manner. Invariably, their toxic effects were dose-and time-dependent while NPs in general were significantly more toxic. Notably, NPs caused oxidative stress, genotoxicity and inflammatory responses, as seen by significant induction of ROS, LPO, MN, TNF-α, IL-1β and IL-6. Thus, the study tends to suggest that separate health safety standards would be required for micrometer and nanometer scale particles of dolomite.