Characterization of pig liver purified cytochrome P-450 isoenzymes for ochratoxin A metabolism studies.

In this paper, we report the characterization of 4 isolated, constitutive cytochrome P-450 fractions from pig liver microsomes. The two predominant forms, A2 and A3, exhibit several similarities: a Mr of 54 kDa, a lambda max CO-Fe++ at 448 nm, a relatively high ratio of the high-spin form and an immunological cross-reaction with polyclonal antibodies against rat liver P-450 IIB1. It is shown that these forms and the minor form Ba, which are active as benzphetamine N-demethylase, play an important metabolic role in ochratoxin A oxidation. This mycotoxin was oxidized by at least 3 different pig liver cytochrome P-450 fractions, each producing different metabolites, namely (4R)-, (4S)-hydroxyochratoxin A, and a new lipophilic metabolite. Since the pig is particularly susceptible to ochratoxin A toxicity, it represents a good animal model for in vitro studies of the metabolism of such a xenobiotic.     

Development and evaluation of a hearing aid manual in the Malay language

Objective: This study aimed to (a) translate a hearing aid (HA) manual into Malay language and revise the translated manual based on best practice guidelines; (b) compare the effectiveness of the translated and the revised Malay HA manuals in helping individuals to perform HA management tasks.

Design: Cross-sectional, randomised, single-blinded study.

Study sample: An Oticon-Dynamo HA manual was translated and revised based on best practice guidelines. Ninety participants aged 55?years and above participated in this study. They were randomly assigned into the control group (received translated manual) and the experimental group (received the revised translated manual). The Hearing Aid Management (HAM) test, which was developed in a previous study, was conducted to evaluate participant’s ability to perform HA management tasks using the translated and the revised version of Malay HA manual.

Results: The revised Malay HA manual had a lower reading grade level relative to the initial translated Malay HA manual. The ability to perform HA management tasks was better in the experimental group (mean = 12.2, SD = 1.15) versus the control group (mean = 8.7, SD = 2.11).

Conclusion: Further revision of existing HA manuals based on best practice guidelines is recommended to help individuals better manage their HAs.     

Effects of a Basketball Activity on Lung Capillary Blood Volume and Membrane Diffusing Capacity,Measured by NO/CO Transfer in Children

In both children and adults, acute exercise increases lung capillary blood volume (Vc) and membrane factor (Dm_CO). We sought to determine whether basketball training affected this adaptation to exercise in children. The purpose of this study was to determine the effects of two years sport activity on the components of pulmonary gas transfer in children. Over a 2-yr period, we retested 60 nine year old boys who were initially separated in two groups: 30 basketball players (P) (9.0 ± 1.0 yrs; 35.0 ± 5.2 kg; 1.43 ± 0.05 m), and matched non players controls (C) (8.9 ± 1.0 yrs; 35.0 ± 6.0 kg; 1.44 ± 0.06 m) who did not perform any extracurricular activity, Vc and Dm_CO were measured by the NO/CO transfer method at rest and during sub-maximal exercise. Maximal aerobic power and peak power output was 12% higher in the trained group compared to matched controls (p < 0.05). Nitric oxide lung transfer (TL_NO) per unit lung volume and thus, Dm_CO per unit of lung volume (VA) were higher at rest and during exercise in the group which had undergone regular basketball activity compared to matched controls (p < 0.05). Neither lung capillary blood volume nor total lung transfer for carbon monoxide (TL_CO) were significantly different between groups. These results suggest that active sport can alter the properties of the lung alveolo-capillary membrane by improving alveolar membrane conductance in children.

Key Points

• Trained children had greater Dm_CO/VA and Dm_CO/Vc ratios compared with control children during exercise.
• The mechanisms by which basketball playing children were thought to improve lung diffusion are speculative.
• Further work will be required to determine the kinetics of the alteration in Dm when children switch from non players to players status or vice-versa.

Key Words: Membrane diffusing capacity, pulmonary capillary blood volume, alveolar volume, children, NO/CO transfer     

Evaluation of an enzyme-linked immunosorbent assay based on crude leishmania histone proteins for serodiagnosis of human infantile visceral leishmaniasis

Human visceral leishmaniasis (VL) is routinely diagnosed by detecting IgG that specifically binds to Leishmania antigens. The enzyme-linked immunosorbent assay (ELISA) remains a widely used method. However, the biggest challenge remains the choice of antigen with the highest specificity and sensitivity. This study is aimed at assessing the diagnostic performances of crude Leishmania histone (CLH) protein-based ELISAs in Mediterranean VL patients. The CLH proteins were biochemically purified from promastigote nuclear extracts. Their reactivities were analyzed by Western blotting (WB) using rabbit polyclonal antibodies against Leishmania recombinant histones and sera from VL patients, respectively. Then, the diagnostic potential of CLH proteins was validated by the CLH-based ELISA using 42 infantile VL patients' sera and 70 control subjects. The CLH-based ELISA performance was compared to that of the soluble Leishmania antigen (SLA)- and the recombinant K39 (rK39)-based ELISAs. Analysis of the WB profile with the use of polyclonal antibodies confirmed the histone origin of low molecular mass proteins (12 to 16 kDa). All VL samples tested presented antibodies reacting against different antigen fractions; however, recognition patterns were different depending on the reactivity of each serum. CLH-based ELISA showed an excellent ability to discriminate between VL cases and healthy controls (97.6% sensitivity and 100% specificity). It had a diagnostic performance similar to that of rK39-based ELISA (97.6% sensitivity and 97.1% specificity, P = 0.5) and a better serodiagnosis accuracy than the SLA-based ELISA (85.7% sensitivity and 90% specificity, P < 0.05). Therefore, crude Leishmania histone extract could be a valuable antigen for clinical use.     

Acoustic breath-phase detection using tracheal breath sounds

Current breathing flow estimation methods use tracheal breath sounds, but one step of the process, ‘breath phase (inspiration/expiration) detection’, is done by either assuming alternating breath phases or using a second acoustic channel of lung sounds. The alternating assumption is unreliable for long recordings, non-breathing events, such as apnea, swallow or cough change the alternating nature of the phases. Using lung sounds intensity requires the addition of a secondary channel and the associated labor. Hence, an automatic and accurate method for breath-phase detection using only tracheal sounds would be of great benefit. We present a method using several breath sound parameters to differentiate between the two respiratory phases. The proposed method is novel and independent of flow level; it requires only one prior- and one post-breath sound segment to identify the phase. The proposed method was tested on data from 93 healthy individuals, without any history of pulmonary diseases breathing at 4 different flow levels. The most prominent features were from the duration, volume and shape of the sound envelope. This method has shown an accuracy of 95.6% with 95.5% sensitivity and 95.6% specificity for breath-phase identification without assuming breath-phase-alteration and/or using any other information.