Browsing by Author "Maritz, J. S."

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    'n Oorsig van die bepaling van die vroeë bakterisidiese aktiwiteit van verskeie antituberkilosemiddels
    (AOSIS, 2003) Donald, P. R.; Sirgel, F. A.; Venter, A.; Fourie, P. B.; Parkin, D. P.; Seifart, H. I.; Van de Wal, B. W.; Maritz, J. S.
    The early bactericidal activity (EBA) of an antituberculosis agent is the daily decline in log10 colony forming units of M tuberculosis per ml of sputum during the first two days of treatment with the agent. It reflects the capacity of an agent to kill the actively metabolising organisms in tuberculosis lung cavities. It offers a relatively cheap means to evaluate the antituberculosis activity of an agent in a small group of patients within a matter of months. This article summarizes the authors’ experience in seven published EBA studies and identifies sources of variation in the procedure. The patients who participated in these studies had a mean age of 33 years, a mean weight of 50 kg and there was extensive or massive involvement of the lungs in 55% of patients. The highest EBA values (0,50-0,66) were found in groups of patients receiving isoniazid and the lowest values (0,05 and 0,09 respectively), in patients receiving the aminoglycosides amikacin and paromomycin in a dose of 15 mg/kg body weight. The variation in EBA in 248 patients was 0,0312 and the variation ascribable to the process of sputum production and collection was 0,0233. This implies that the different aspects of sputum production and collection involved in obtaining a representative sputum sample are responsible for most of the variation in EBA results. The selection of patients for inclusion in EBA studies and their ability to co-operate in producing a representative sputum specimen are of critical importance in the successful completion of EBA studies.
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    Thymic size at birth in preterm infants with severe respiratory distress syndrome can be used to predict the likelihood of survival : a retrospective cohort study
    (Health & Medical Publishing Group, 2010) Tooke, L. J.; Smith, J.; Griffith-Richards, S.; Maritz, J. S.
    Objective. To determine whether the thymic size in preterm infants with severe respiratory distress syndrome (RDS) canbe used to predict survival. We also set out to determine which antenatal and postnatal factors have an influence on, or correlation with, thymic size. Methods. A retrospective study was conducted on 55 consecutive preterm infants who were ventilated for RDS. A chest X-ray (CXR) was taken within the first 24 hours, and the cardiothymic/thoracic ratio (CT/T ratio) calculated. This ratio was then correlated with outcome, as well as antenatal maternal and postnatal factors. Results. Of the 49 infants included in the study (6 were excluded), 15 died and 34 survived. There was a statistically significant correlation between the CT/T ratio and survival (p=0.029). In those infants above 1 030 g, the CT/T ratio was more significant (p=0.038) than birth weight in predicting survival. The severity of RDS did not influence the CT/T ratio. The only maternal and postnatal factors influencing CT/T ratio were the presence of pre-eclamptic toxaemia (PET) and birth by caesarean section (CS), but these factors did not influence likelihood of survival. Factors found to be not associated with thymic size were antenatal steroid administration, maternal HIV status, clinical chorio-amnionitis, gender, gestational age (small or appropriate weight) and lymphocyte count. Conclusions. A small thymus measured in the first 24 hours can be used to predict likelihood of survival in infants weighing more than 1 030 g, but not in smaller infants. Prenatal stress associated with PET and indication for CS may cause the thymus to shrink.