The association between environmental lead exposure with aggressive behavior, and dimensionality of direct and indirect aggression during mid-adolescence: Birth to Twenty Plus cohort.

Chronic lead exposure is associated with neurological ill-health including anti-social behavior such as aggressive behavior. The main aim of this study was to examine the association between lead exposure at 13years old and dimensions of aggressive behavior during mid-adolescence. The study sample included 508 males and 578 females in mid-adolescence (age 14 to 15years) from the Birth to Twenty Plus cohort in Johannesburg, South Africa. Blood samples collected at age 13years were used to measure blood lead levels. Seventeen items characterizing aggression from the Youth Self Report questionnaire were used to examine aggressive behavior. Principal Component Analysis was used to derive composite variables from the original data for aggressive behavior; and data were examined for an association between blood lead levels and dimensionality of direct and indirect aggression and disobedience during mid-adolescence. We also examined the dimensions of aggression during mid-adolescence in relation to gender and socio-demographic factors. Blood lead levels ranged from 1 to 28.1µg/dL. Seventy two percent of males and 47.7% of females in the study had blood lead levels ≥5µg/dL. There was a positive association between elevated blood lead levels and direct aggression (p<0.05). Being male was positively associated with direct aggression (p<0.001) but, negatively associated with indirect aggression (p<0.001). Maternal education and age at birth were negatively associated with direct aggression during mid-adolescence. The significant association between elevated blood lead levels and direct aggressive behavior observed in this study may shed light on a possible environmental toxicological contribution to aggressive behavior in South African youth; and most importantly the type of aggressive behavior associated to lead exposure.

The association between elevated blood lead levels and violent behavior during late adolescence: The South African Birth to Twenty Plus cohort.

Epidemiological studies have shown the adverse neuro-behavioral health effects of lead exposure among children, in particular. However, there is lack evidence in this regard from developing countries. The main aim of this study was to assess the association between blood lead levels (BLLs) during early adolescence and violent behavior in late adolescence. Our study sample from the Birth to Twenty Plus cohort in Soweto-Johannesburg, South Africa included 1332 study participants (684 females). BLLs were measured using blood samples collected at age 13years. Violent behavior was evaluated using data collected at ages 15 to 16years using the Youth Self Report questionnaire. First, bivariate analysis was used to examine data for an association between lead exposure in early adolescence and violent behavior items during late adolescence. Principal Component Analysis (PCA) was used for dimensionality reduction and six violent behavior components were derived. Data were further analyzed for an association between BLLs at age 13years and violent behavior using PCA derived components; to determine the specific type(s) of violent behavior associated with lead exposure. Median whole BLLs were 5.6µg/dL (p<0.001). Seventy five percent of males and 50% of females had BLLs≥5µg/dL. BLLs ranging from 5 to 9.99µg/dL were associated with physical violence (p=0.03) and BLLs≥10µg/dL were associated physical violence and fighting (p=0.02 and p=0.01, respectively). When data were analyzed using continuous BLLs physical violence was associated with lead exposure (p<0.0001). Furthermore, males were more likely to be involved in violence using a weapon (p=0.01), physical violence (p<0.0001), and robbing others (p<0.05) compared to females. The results from this study show the severe nature of violent behavior in late adolescence associated with childhood lead exposure. They highlight the urgent need for preventive measures against lead exposure among children in low or middle income countries such as South Africa.

Outcome of Patients with Severe Abdominal Sepsis in the Intensive Care - Experience at Charlotte Maxeke Johannesburg Academic Hospital

Despite advances in diagnosis; surgery; antimicrobial therapy and intensive care support; the mortality rate associated with intra-abdominal sepsis remains unacceptably high. The aim of the present study was to identify prognostic factors in 54 consecutive cases with abdominal sepsis admitted to the intensive care unit (ICU) over a two-year period; from January 2001 to December 2002. This was a retrospective record review of cases with abdominal sepsis admitted to the ICU. Of 54 patients that were studied; only 14 survived. The mortality rate was 74.1. Non-survivors had significantly longer ICU stay; had more relook laparotomies; more blood transfusions and a significantly higher APACHE II score on admission to the ICU. Other results revealed that non-survivors required significantly more inotropic support and corticosteroids; had a lower paO2/FiO2 ratio and had more total arenteral nutrition days. None of the patients who urvived required dialysis. The number of relook laparotomies were higher in the non-survivors and the maximum number of relook laparotomies were four in the survivors and 13 in the non-survivors. The non-survivors were also more likely to have an open abdomen. We conclude that patients with abdominal sepsis have an extremely high mortality and utilise an enormous amount of limited intensive care resources. The length of ICU stay; APACHE II score on admission; number of relook laparotomies; whether the abdomen was left open or not; and requirement for inotropic support; dialysis; total parenteral nutrition and blood transfusions were predictive of adverse outcomes in these patients

Antifungal effect of mouth rinses on oral Candida counts and salivary flow in treatment-naïve HIV-infected patients.

Oral candidiasis is a major problem in developing countries where antiretroviral therapy is available to a small percentage of the infected population. HIV patients are prone to xerostomia and predisposed to Candida infection. Preventing oral candidiasis is better than the frequent use of antifungals that may lead to the development of drug resistance. This study investigated the ability of commercial mouth rinses and sodium bicarbonate to reduce salivary Candida and to improve the saliva flow of HIV-positive patients. One hundred fifty HIV patients without oral candidiasis were examined for oral lesions initially and after 2, 4, and 12 weeks. Unstimulated saliva was collected; the volume was measured and cultured for yeasts. Subjects were provided with mouth rinses containing either benzydamine hydrochloride, benzydamine hydrochloride with chlorhexidine gluconate, triclosan with sodium fluoride, 5% sodium bicarbonate, or placebo and asked to rinse twice daily for 12 weeks. The effect of the mouth rinses and placebo on Candida counts and saliva flow was analyzed using analysis of variance (ANOVA). A total of 108 patients completed the trial, 35 missed appointments, 4 died, 2 developed oral candidiasis, and 1 herpetic lesion. Triclosan/fluoride decreased the Candida count more than the placebo (p = 0.005) while chlorhexidine/benzydamine hydrochloride (p = 0.001) and triclosan/fluoride mouthrinses (p = 0.002) increased the salivary flow during the initial 4 weeks. The most effective mouth rinse triclosan/fluoride decreased oral Candida counts and increased saliva flow. Studies are needed to determine the efficacy of these mouth rinses for the long-term prevention of clinical oral candidiasis in adult HIV-positive patients.

Staphylococcus aureus bacteraemia at two academic hospitals in Johannesburg.

OBJECTIVES AND METHODS: Staphylococcus aureus bacteraemia (SAB) remains a major problem worldwide. A retrospective study of patients with SAB seen from November 1999 to October 2002 was conducted at two academic hospitals in Johannesburg to determine mortality rates (death within 14 days of submission of blood culture) in patients bacteraemic with methicillin-sensitive (MSSA) and resistant S. aureus (MRSA) and to identify risk factors associated with mortality. RESULTS: Of 449 patients with SAB, 104 (23.2%) died within 14 days of clinically suspected SAB. Of the 204 patients who acquired SAB in hospital, 6 patients died within 2 days, 39 between 2 and 14 days, and 41 more than 14 days after onset of SAB. One hundred and five patients (23.4%) had MRSA bacteraemia, 21 (20%) originating from the community. The MRSA bacteraemia rate among patients with hospital-acquired infection was 41.1%, significantly higher (p < 0.0001) than the 10.3% community-acquired MRSA bacteraemia. Thirty-five (33.3%) of the 105 patients with MRSA bacteraemia died within 14 days, compared with 69 (20.1%) of 344 MSSA patients (p = 0.0048). Admission to the intensive care unit (ICU) was significantly associated with mortality (p < 0.001)--30 of 79 patients admitted to ICU died (38%). Among 222 patients whose HIV status was known, 117 (52.7%) were positive, and of these 32 died (27.4%), a rate not significantly higher than that among HIV-seronegative patients (18 of 105 patients, p = 0.69). CONCLUSIONS: Compared with MSSA, MRSA was shown to be significantly associated with mortality. Stay in ICU and infection with strains resistant to oxacillin, ofloxacin and rifampicin were highly significant predictors for mortality.

Increased prevalence of severe malaria in HIV-infected adults in South Africa.

BACKGROUND: Conflicting reports exist regarding the impact of human immunodeficiency virus (HIV) infection on the risk of severe malaria. We aimed to assess the effect of HIV infection status, advancing immunosuppression, and antimalarial immunity on the severity of malaria. METHODS: A prospective cohort study was conducted. Consecutive hospitalized adult patients with falciparum malaria were tested for HIV antibodies and to determine CD4+ T cell count. Immunity to malaria was assessed by obtaining a history of childhood residence in an area where malaria is endemic. Patients were assessed for features of severe malaria. RESULTS: Three hundred thirty-six patients were enrolled in the study, of whom 32 (10%) had severe malaria. The prevalence of HIV infection was 33%, and 111 patients (33%) were nonimmune to malaria. HIV-infected patients complained more frequently about respiratory and abdominal symptoms and less frequently about rigors and headache. Risk factors for severe malaria determined by multivariate analysis included being nonimmune to malaria, having a positive HIV serostatus, having an elevated parasite count, and having an increased white blood cell count. Risk of severe malaria was increased in HIV-infected patients with a CD4+ T cell count of < 200 x 10(6) cells/L (P < or = .001). Nonimmune HIV-infected patients were significantly more likely to have severe malaria (13 [36%] of 36 patients) than were nonimmune non-HIV-infected patients (9 [12%] of 75 patients; odds ratio, 4.15 [95% confidence interval, 1.57-10.97]; P = .003). HIV serostatus did not affect risk of severe malaria in the group from an area with endemicity (5 [7%] of 74 HIV-infected patients had severe malaria, and 5 [3%] of 151 non-HIV-infected patients had malaria; P = .248). CONCLUSIONS: HIV-infected nonimmune adults are at increased risk of severe malaria. This risk is associated with a low CD4+ T cell count. This interaction is of great public health importance.

Serum procalcitonin as an early marker of neonatal sepsis.

BACKGROUND: It has recently been suggested that procalcitonin (PCT) is of value in the diagnosis of neonatal sepsis, with varying results. This study was to evaluate the role of PCT as a single early marker of neonatal sepsis. SETTING: Neonatal Unit, Johannesburg Hospital, and Microbiology Laboratory, National Health Laboratory Service (NHLS), South Africa. SUBJECTS AND METHODS: Neonates undergoing evaluation for sepsis between April and August 2002 were eligible for inclusion. Patients were categorised into 'no infection', 'possible infection' and 'definite infection' on the basis of C-reactive protein (CRP), white cell count (WCC), platelet count and blood culture results. PCT was correlated with infection categories. RESULTS: One hundred and eighty-three neonates were enrolled. One hundred and eighteen had no infection, 52 possible infection and 13 definite infection. PCT differed significantly among infection categories (p < 0.0001) and correlated significantly with CRP at presentation (correlation coefficient 0.404, p < 0.001) and CRP at 24 hours (correlation coefficient 0.343, p < 0.001). PCT predicted 89.5% of definite infection. Receiver operating characteristic (ROC) analysis for PCT to predict definite infection showed odds ratio (OR) 1.145 (95% confidence interval (CI): 1.05-1.25) with an area under the curve of 0.778. PCT had a negative predictive value of 0.95 (95% CI: 0.915-0.988) for definite infection. CONCLUSIONS: Although PCT was significantly related to the category of infection, it is not sufficiently reliable to be the sole marker of neonatal sepsis. PCT would be useful as part of a full sepsis evaluation, but is relatively expensive. A negative PCT on presentation may rule out sepsis, but this needs to be evaluated further.

Multiple method comparison: statistical model using percentage similarity.

BACKGROUND: Method comparison typically determines how well two methods agree. This is usually performed using the difference plot model, which measures absolute differences between two methods. This is often not applicable to data with wide ranges of absolute values. An alternative model is introduced that simplifies comparisons specifically for multiple methods compared to a gold standard. METHODS: The average between a new method and the gold standard is represented as a percentage of the gold standard. This is interpreted as a percentage similarity value and accommodates wide ranges of data. The representation of the percentage similarity values in a histogram format highlights the accuracy and precision of several compared methods to a gold standard. The calculation of a coefficient of variation further defines agreement between methods. RESULTS: Percentage similarity histograms of several new methods can be compared to a gold standard simultaneously, and the comparison easily visualized through use of a single 100% similarity reference line drawn common to all plots. CONCLUSION: This simple method of comparison would be particularly useful for multiple method comparison and is especially applicable for centers collating for external quality assessment or assurance programs to demonstrate differences in results between laboratories.