Effect of carbon dioxide injection on production of wood cement composites from waste medium density fiberboard (MDF)

The possibility of recycling waste medium density fiberboard (MDF) into wood-cement composites was evaluated. Both new fibers and recycled steam exploded MDF fibers had poor compatibility with cement if no treatment was applied, due to interference of the hydration process by the water soluble components of the fiber. However, this issue was resolved when a rapid hardening process with carbon dioxide injection was adopted. It appears that the rapid carbonation allowed the board to develop considerable strength before the adverse effects of the wood extractives could take effect. After 3-5 min of carbon dioxide injection, the composites reached 22-27% of total carbonation and developed 50-70% of their final (28-day) strength. Composites containing recycled MDF fibers had slightly lower splitting tensile strength and lower tensile toughness properties than those containing new fibers especially at a high fiber/cement ratio. Composites containing recycled MDF fibers also showed lower values of water absorption. Unlike composites cured conventionally, composites cured under CO(2) injection developed higher strength and toughness with increased fiber content. Incorporation of recycled MDF fibers into wood cement composites with CO(2) injection during the production stage presents a viable option for recycling of this difficult to manage waste material.

Polymerase chain reaction for diagnosis of human immunodeficiency virus infection in infancy in low resource settings

BACKGROUND

Diagnosis of human immunodeficiency virus (HIV) is essential for accessing treatment. Current HIV diagnostic protocols for infants require adaptation and validation before they can be implemented in the developing world. The timing and type of HIV assays will be dictated by country-specific circumstances and experience from similar settings. The performance of an HIV-1 DNA polymerase chain reaction (PCR) test, and in particular a single test at 6 weeks of age, in diagnosing HIV subtype C infection acquired in utero or peripartum was assessed.

METHODS

A retrospective review of 1825 Amplicor HIV-1 DNA PCR version 1.5 tests performed between 2000 and 2004 in 2 laboratories in Johannesburg, South Africa on 769 effectively non-breast-fed infants from 3 clinically well characterized cohorts was undertaken. The HIV status of each infant was used as the standard against which the HIV PCR results were compared.

RESULTS

The overall sensitivity and specificity of the HIV PCR test were 99.3 and 99.5% respectively. A single test was 98.8% sensitive and 99.4% specific in the 627 infants tested at 6 weeks of age (58 HIV-infected and 569 HIV-uninfected). Repeat testing of all positive HIV PCR tests minimized false positive results.

CONCLUSIONS

In resource-poor settings where HIV PCR testing in an environment of good laboratory practice is feasible, a single 6-week HIV DNA PCR test can increase identification of HIV-infected children substantially from current levels. Further operational research on how best to implement and monitor such a diagnostic protocol in specific local settings, especially in breast-fed infants, is necessary.

Survival of very-low-birth-weight infants according to birth weight and gestational age in a public hospital

OBJECTIVES

To determine the survival rates for infants weighing 500 - 1 499 g according to birth weight (BW) and gestational age (GA).

DESIGN

This was a retrospective cohort study. Pregnancy and delivery data were collected soon after birth and neonatal data at discharge or at death.

SETTING

Chris Hani Baragwanath Hospital (CHBH), a public-sector referral hospital, affiliated to the University of the Witwatersrand.

SUBJECTS

Live births weighing between 500 g and 1 499 g delivered at or admitted to CHBH from January 2000 to December 2002.

OUTCOME MEASURES

BW and GA-specific survival rates for all live infants born at CHBH and for those admitted for neonatal care.

RESULTS

Seventy-two per cent of infants survived until discharge. The survival to discharge rate was 32% for infants weighing < 1 000 g, and 84% for those weighing 1 000 - 1 499 g. Survival rates at 26, 27 and 28 weeks' gestation were 38%, 50% and 65% respectively. Survival rates for infants admitted to the neonatal unit were better than rates for all live births, especially among those weighing < 1 000 g or with a GA < 28 weeks. There was a marked increase in survival between the 900 - 999 g and 1 000 - 1 099 g weight groups. Provision of antenatal care, caesarean section, female gender and an Apgar score more than 5 at 1 or 5 minutes were associated with better survival to hospital discharge.

CONCLUSION

Survival among infants weighing less than 1 000 g is poor. In addition to severe prematurity, the poor survival among these infants (< 1 000 g) is most likely related to the fact that they were not offered mechanical ventilation. Mechanical ventilation should be offered to infants weighing < 1 000 g as it may improve their survival even in institutions with limited resources.

Development of a modified hollow fibre assay for studying agents targeting the tumour neovasculature

BACKGROUND

Previous studies have shown extensive vascularisation surrounding subcutaneously implanted fibres when the duration of the US National Cancer Institute (NCI) hollow fibre assay was prolonged.

MATERIALS AND METHODS

The feasibility of adapting the NCI assay for evaluating agents targeting the tumour vasculature was investigated in vitro and in vivo. Finally, in the optimised assay, changes in neovasculature formation around the fibres following treatment with the anti-vascular agent paclitaxel were quantified by immunohistochemistry.

RESULTS

Correlations between cell number seeded, time in culture and vascular endothelial growth factor (VEGF) secretion were seen. In vivo studies showed that transplanting single rather than 3 fibres at a site reduced inflammation, reducing the length of the fibre transplanted, as did without any significant loss in cell growth over 21 days. A statistically significant reduction in neovascularisation surrounding the fibres was seen accompanying paclitaxel treatment.

CONCLUSION

Modifications made here to the NCI hollow fibre assay demonstrate its potential for analysing anti-tumour vasculature agents.

Evaluation of transgenic approaches for controlling tuber moth in potatoes

A wide spectrum of strategies to genetically engineer potato plants resistant to potato tuber moth, Phthorimaea operculella (Zeller), have been investigated. The potato cv Iwa was transformed with a range of genes under the transcriptional control of the CaMV 35S promoter using Agrobacterium-mediated gene transfer. The transferred genes encode protease inhibitors (spleen inhibitor and alpha1-antitrypsin inhibitor), biotin-binding proteins (avidin and streptavidin) and Cry proteins (crylAc9, cry1Ba1, crylCa5 and cry9Aa2). Of these three transgenic approaches, cry genes have proved the most useful. In order to control the expression of the cry genes in foliage and not in the tubers a light-inducible Lhca3 promoter from potato was also used. The interaction of different cry genes was investigated using an experimental approach to simulate gene pyramiding in potato. Potato plants transgenic for both the crylAc9 and cryAa2 genes were developed and evaluated to help provide a more durable resistance to potato tuber moth.

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.

Transgenic Pinus radiata from Agrobacterium tumefaciens-mediated transformation of cotyledons

A method for Agrobacterium tumefaciens-mediated transformation of Pinus radiata cotyledon explants was developed using commercially available open-pollinated seed. Pinus radiata is the most widely planted commercial conifer species in the Southern Hemisphere. Reports on transformation of this species have relied on particle bombardment of embryogenic callus derived from immature embryos. The main drawback to the method is the small number of genotypes that are amenable to transformation and regeneration. Since more than 80% of genotypes of radiata pine can be regenerated using cotyledons from mature seed, cotyledon explants were cocultivated with A. tumefaciens strain AGL1 containing a plasmid coding for the neomycin phosphotransferase II (nptII) gene and the beta-glucuronidase (GUS) gene (uidA). Transformed shoots were selected using either geneticin or kanamycin. Critical factors for successful transformation were survival of the cotyledons after cocultivation and selection parameters. Of the 105 putative transformants that were recovered from selection media, 70% were positive for integration of the nptII gene when analysed by PCR. GUS histochemical assay for uidA expression was unreliable because of reaction inhibition by unidentified compounds in the pine needles. Further, only 4 of the 26 independent transformants characterised by PCR and Southern analysis contained an intact copy of both genes. The remaining 22 transformants appeared to have a truncated or rearranged copy of the T-DNA. It is possible that the truncation/rearrangements are due to the Cauliflower mosaic virus (CaMV) 35S promoter. Analysis of the T-DNA junction sites and sequencing of the introduced DNA will help elucidate the nature of T-DNA insertion so that genetic modification of radiata pine can be targeted effectively.

Vinflunine potentiates the activity of cisplatin but not 5-fluorouracil in a transplantable murine adenocarcinoma model

BACKGROUND

Vinflunine is a novel Vinca alkaloid currently undergoing Phase II clinical trials, which have previously demonstrated anti-vascular effects in a transplantable murine colon adenocarcinoma model. Previous studies with compounds showing similar effects in combination with standard anti-cancer agents have demonstrated an improved efficacy relative to the standard agents.

MATERIALS AND METHODS

In this study the synergistic effects of administering vinflunine in combination with either Cisplatin (CPL) or 5-fluorouracil (5-FU) were investigated in a well-differentiated transplantable murine colon adenocarcinoma model (MAC 29).

RESULTS

Vinflunine significantly potentiated the anti-tumour effects of CPL, but had little effect in combination with 5-FU. Using Hoescht 33342 dye labelling of the functional vasculature, clear evidence of vascular shutdown was seen for treatment groups including vinflunine.

CONCLUSION

These data demonstrate that the combination of vinflunine and CPL has significant preclinical anti-tumour activity against a transplantable murine adenocarcinoma model that is related to the anti-vascular effects of vinflunine.

Influence of Agrobacterium tumefaciens strain on the production of transgenic peas ( Pisum sativum L.)

We compared the efficiency of two Agrobacterium tumefaciens strains, AGL 1 and KYRT1, for producing transgenic pea plants. KYRT1 is a disarmed strain of Chry5 that has been shown to be highly tumourigenic on soybean. The efficacies of the strains were compared using cotyledon explants from three pea genotypes and two plasmids. The peas were sourced from field-grown plants over three Southern Hemisphere summer seasons. Overall, KYRT1 was found to be on average threefold more efficient than AGL 1 for producing transgenic plants. We suggest that KYRT1 is sensitive to cocultivation temperature as the expected increase in efficiency was not achieved at high laboratory temperatures.

Combretastatin A-1 phosphate potentiates the antitumour activity of cisplatin in a murine adenocarcinoma model

BACKGROUND

The tubulin depolymerizing drug Combretastatin A-1 phosphate (CA1P), a water-soluble derivative of combretastatin A-1, has been recently shown to have a better efficacy in experimental models than the clinically active, close structural analogue, combretastatin A-4 phosphate (CA4P). Previous studies with CA4P in combination with standard anti-cancer agents have demonstrated improved efficacy relative to the standard agents.

MATERIALS AND METHODS

In this study the synergistic effects of administering CA1P in combination with cisplatin (CPL) in a well-differentiated transplantable murine colon model (MAC 29) was evaluated.

RESULTS

CA1P at 100 mgkg-1 significantly potentiated the anti-tumour effects of CPL. The effect with CPL was similar to that seen for CA1P at its maximum tolerated dose (MTD) alone.

CONCLUSION

These data demonstrate that the combination of CA1P and CPL has significant preclinical antitumour activity against a transplantable murine adenocarcinoma model that is related to the antivascular effects of CA1P.

Antitumour 2-(4-aminophenyl)benzothiazoles generate DNA adducts in sensitive tumour cells in vitro and in vivo

2-(4-Aminophenyl)benzothiazoles represent a potent and highly selective class of antitumour agent. In vitro, sensitive carcinoma cells deplete 2-(4-aminophenyl)benzothiazoles from nutrient media; cytochrome P450 1A1 activity, critical for execution of antitumour activity, and protein expression are powerfully induced. 2-(4-Amino-3-methylphenyl)benzothiazole-derived covalent binding to cytochrome P450 1A1 is reduced by glutathione, suggesting 1A1-dependent production of a reactive electrophilic species. In vitro, 2-(4-aminophenyl)benzothiazole-generated DNA adducts form in sensitive tumour cells only. At concentrations >100 nM, adducts were detected in DNA of MCF-7 cells treated with 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203). 5F 203 (1 microM) led to the formation of one major and a number of minor adducts. However, treatment of cells with 10 microM 5F 203 resulted in the emergence of a new dominant adduct. Adducts accumulated steadily within DNA of MCF-7 cells exposed to 1 microM 5F 203 between 2 and 24 h. Concentrations of the lysylamide prodrug of 5F 203 (Phortress) > or = 100 nM generated adducts in the DNA of sensitive MCF-7 and IGROV-1 ovarian cells. At 1 microM, one major Phortress-derived DNA adduct was detected in these two sensitive phenotypes; 10 microM Phortress led to the emergence of an additional major adduct detected in the DNA of MCF-7 cells. Inherently resistant MDA-MB-435 breast carcinoma cells incurred no DNA damage upon exposure to Phortress (< or = 10 microM, 24 h). In vivo, DNA adducts accumulated within sensitive ovarian IGROV-1 and breast MCF-7 xenografts 24 h after treatment of mice with Phortress (20 mg kg(-1)). Moreover, Phortress-derived DNA adduct generation distinguished sensitive MCF-7 tumours from inherently resistant MDA-MB-435 xenografts implanted in opposite flanks of the same mouse.

Anti-tumor and anti-vascular effects of the novel tubulin-binding agent combretastatin A-1 phosphate

The combretastatins are derived from an African medicinal plant Combretum caffrum (Combretaceae). They have previously been shown to be potent inhibitors of microtubule assembly that cause marked haemorrhagic necrosis in murine subcutaneous tumors. Promising clinical trial results with combretastatin A-4 phosphate led to this investigation of the anti-tumor and anti-vascular effects of a close structural analog, combretastatin A-1 phosphate. This compound caused identical disruption of the tubulin cytoskeleton in HUVECs in vitro at similar concentrations and duration of exposure as combretastatin A-4 phosphate. Treatment of a well-vascularised murine colon adenocarcinoma (MAC 29) with an effective dose (150 mg/kg) of combretastatin A-1 phosphate resulted in a dramatic decrease in functional vascular volume 2 hours after administration. Vascular shutdown was complete within 4 hours after treatment apart from in small areas of the tumor periphery. Morphological examination of hepatic deposits of HT29 and DLD-1 human colon tumors in nude mice demonstrated that combretastatin A-1 phosphate displays greater anti-tumor effects than the A-4 analog at the same dose and this order of activity (A-1 > A-4) is mirrored in the subcutaneous site with the same tumor type. In summary, combretastatin A-1 phosphate can exert its anti-tumor action via an anti-vascular mechanism. The results indicate that, despite having similar in vitro anti-tubulin properties, combretastatin A-1 phosphate seems to have greater in vivo anti-tumor activity than combretastatin A-4 phosphate at the same doses and may therefore be more successful in the clinic.

The intrauterine environment is a strong determinant of glucose tolerance during the neonatal period, even in prematurity

The aim of this study was to determine the contribution of birth weight and gestational age to glucose tolerance in premature neonates. The study group consisted of 100 premature and/or small-for-gestational age infants. Anthropometric measurements were performed both at birth and at the time of a standardized milk feed carried out at 19.6 +/- 12.1 d (range, 1-65 d) after birth. Fasting and postprandial glucose and insulin levels were measured. Birth weight, as a proxy mirror of the intrauterine environment, was found to influence the glucose concentration following a standardized milk feed (beta = -0.46; P = 0.01 for birth weight z-score with 60-min glucose level), whereas gestational age did not. Small-for-gestational age neonates had higher 60-min insulin levels than appropriate-for-gestational age neonates (115.4 +/- 9.5 vs. 68.4 +/- 14.2; P < 0.05) despite similar glucose levels. Neonates born of mothers who were on antihypertensive treatment were smaller and had a higher insulin secretory response than neonates from normotensive mothers. Postnatal growth velocity (kilograms per day) correlated with birth weight (beta = -0.65; P < 0.0001) and insulin resistance (beta = -0.31; P = 0.0004), independently of each other. This study shows that glucose tolerance of the neonate is determined by weight attained at birth irrespective of gestational age and that maternal blood pressure may influence insulin sensitivity of the newborn. Furthermore, catch-up growth in neonates is determined by birth weight and insulin sensitivity.

A comparison of high versus low dose recombinant human erythropoietin versus blood transfusion in the management of anaemia of prematurity in a developing country

The purpose of this study was to evaluate the effectiveness of early treatment with erythropoietin (EPO) in two different treatment regimes (high vs. low dose) in comparison to the conventional treatment of packed red blood cell (PRBC) transfusions in the management of anaemia of prematurity in a country with limited resources. An open controlled trial was conducted on 93 preterm infants (7 days postnatal age, 900-1500 g birthweight). Patients were randomly assigned either to a low dose (250 IU/kg), a high dose (400 IU/kg), or a control group. EPO was administered subcutaneously three times a week and all infants received 6 mg/kg iron orally from study entry to endpoint of therapy. Haematological parameters were measured and compared. The success was defined as an absence of transfusions and a haematocrit that did not fall below 30 per cent during the time period that the infants were in the study. The three groups were statistically comparable at study entry with respect to gestational age, birthweight, Apgar scores, and haematological values. Over the period that the infants were in the study, 75 per cent of the low dose group and 71 per cent of the high dose group met the criteria for success compared with 40 per cent in the control group (p < 0.001). However, there was no significant difference in the number of transfusions when the low and high EPO dose groups (9.5 per cent) were combined and compared with the control group (26.7 per cent) p = 0.0587. It was concluded that in stable infants, 900-1500 g, where phlebotomy losses are minimized and stringent transfusion guidelines are adhered to, EPO does not significantly decrease the number of transfusions. A conservative approach in the management of anaemia of prematurity, is a viable alternative in areas with limited resources.

Combretastatin A-1 phosphate a novel tubulin-binding agent with in vivo anti vascular effects in experimental tumours

In view of the clinical potential of a number of natural products, Combretastatin A-1 phosphate was developed as a water-soluble derivative of combretastatin A-1. This study examined the anti-tumour activity of this compound against an experimental colon tumour (MAC29) in mice. A comparison was made with the clinically active combretastatin A-4 phosphate. The new compound was well-tolerated up to a dose of 250 mg/kg and was more effective at producing tumour growth delays than the A-4 analogue. Significant growth delays were seen at a dose of 50 mg/kg whereas the A-4 phosphate produced no measurable growth delay until a dose of 150 mg/kg was administered. Histological examination of treated tumours indicated that combretastatin A-1 phosphate caused very severe haemorrhagic necrosis in the tumour tissue and analysis of the sections indicated that almost 94 percent of the tumour was dead within 24 hours of treatment. The mechanism of action of combretastatin A-1 phosphate appears to be similar to the A-4 phosphate in that tumour vascular shutdown occurs within 4 hours of treatment. In summary combretastatin A-1 phosphate, the water-soluble analogue of combretastatin A-1, is more potent against a well-vascularised murine colon tumour than its predecessor, combretastatin A-4 phosphate. These data suggest this compound may have potential for clinical development.

Hematological reference ranges in black very low birth weight infants

This study compared hematological reference ranges in black very low birth weight infants to previously published values established predominantly on white subjects. Ninety-four healthy, black, premature babies with a birth weight of 800 to 1500 g at 2-7 days of age were enrolled as part of a study comparing blood transfusions and high- versus low-dose recombinant erythropoietin in anaemia of prematurity. Peripheral venous blood was collected for a full blood count and differential, fetal hemoglobin and erythropoietin levels. The hematological parameters observed in black very low birth weight neonates are similar to previously published reference ranges, except that lower limits of normal were observed for hemoglobin and the red cell indices.

Rapid-extraction oxidation process to recover and reuse copper chromium and arsenic from industrial wood preservative sludge

Chromated copper arsenate (CCA) wood preservative can form insoluble sludges when the hexavalent chromium component is reduced by wood extractives, wood particles and preservative additives in the solution. This sludge accumulates in treating solution work tanks, sumps and in-line filters and must be disposed of as hazardous wastes by waste disposal companies at high costs. A number of commercial sludges were investigated and found to contain 18-94% copper, chromium and arsenic as oxides combined with sand, oil, wood particles, additives and wood extractives. We have developed a multi-stage recycling process whereby approximately 97% of the CCA components are recovered from the sludge. It involves extraction with sodium hypochlorite to remove and oxidize chromium (more than 90%) and extract most of the arsenic (approx. 80%) followed by extraction of the copper and remaining arsenic and chromium with phosphoric acid. The phosphoric acid extract contains some trivalent chromium, which is subsequently oxidized by sodium hypochlorite. The combined oxidized extract containing CrVI, CuII and AsV was compatible with CCA treating solutions and could be re-used commercially for treating wood without having a significant effect on the preservative fixation rate or the leach resistance of the treated wood. A cost analysis showed that the economic savings from recovery of CCA chemicals and reduced landfill costs exceeded the variable costs for materials and energy for the process by as much as Can $966 per tonne of sludge if sodium sulfite can be acquired in bulk quantities for the process.

Is prophylaxis of early-onset group B streptococcal disease appropriate for South Africa?

BACKGROUND

Early-onset group B streptococcal (GBS) disease in neonates can be prevented by the use of intrapartum chemoprophylaxis. There are two prevention strategies, one based on risk factors and the other on culture screening for GBS. This study sought to establish whether GBS chemoprophylaxis is appropriate in a developing country such as South Africa.

METHODS

All neonates with early-onset GBS disease born at Johannesburg Hospital between 1 January 1995 and 21 December 1997 were reviewed. Data were collected prospectively between 1 January and 31 October 1998. Data included demographic information, obstetric information, disease characteristics, admission details and mortality. The approximate cost of implementing both strategies was determined.

RESULTS

The overall incidence of early-onset GBS was 1.16 per 1,000 live births. The rate was significantly greater in 1998 compared with the previous years. Most of the babies were born preterm (70%), and 60% required admission to the neonatal intensive care unit (ICU) (a total of 81 ICU days). Twelve of the babies died. Assuming that chemoprophylaxis would reduce the number of ICU days by half, this would save an amount of R52,000. Culture-based chemoprophylaxis would cost R10 million, whereas an approach based on risk factors would cost R31,140.

CONCLUSION

In conclusion, we feel that early-onset GBS disease is sufficiently prevalent in our unit to justify the implementation of a chemoprophylaxis strategy based on risk factors. Whether other units should adopt a similar approach would depend on the local incidence of early-onset GBS.

Serial interleukin 6 measurements in the early diagnosis of neonatal sepsis

The objective of the present study was to evaluate serial interleukin 6 (IL6) levels in the early diagnosis of neonatal sepsis. Subjects included 255 neonates from the Neonatal Unit of Johannesburg Hospital evaluated for suspected sepsis between February and May 1998. All infants had IL6, full blood count (FBC), C reactive protein (CRP) and blood cultures done at presentation. CRP and IL6 were repeated after 24 h. Infants were categorized into groups according to the likelihood of infection on the basis of clinical presentation, CRP, FBC and culture results, i.e., group 1 (no infection) to group 4 (definite infection). IL6 was compared between the groups by the U-test of Mann-Whitney; stepwise logistic regression was done to establish the best predictors of infection, sensitivity, specificity, positive and negative predictive values were determined. The initial IL6 level was significantly raised in those infants with possible infection [880.67 pg/ml (2966.04), p value 0.0104], probable infection [422.62pg/ml (4077.7), p value 0.0021] and definite infection [11164.39pg/ml (24139.77), p value 0.0000] as compared to those infants without infection [58.65 (182.4)]. The best predictors of infection were the combination of the initial IL6 value and CRP value after 24 h (goodness of fit 97.7 per cent). An initial IL6 value below 20 pg/ml gave a negative predictive value of 90.18 per cent. It is concluded that an IL6 value done at the time of presentation of signs and symptoms suggestive of infection is useful in the early diagnosis of neonatal sepsis. In particular, an initial IL6 value below 20 pg/ml may allow antibiotics to be withheld in a number of infants evaluated for sepsis. There is no benefit in serial determination of IL6 in the diagnosis of neonatal sepsis.

Synthesis and antitumour activity of new derivatives of flavone-8-acetic acid (FAA). Part 4: Variation of the basic structure

A range of 11 derivatives of flavone-8-acetic acid (FAA) in which the structure has been substantially altered in different ways have been prepared and their anti-tumour activity evaluated in vitro against a panel of human and murine tumour cell lines and in vivo against MAC 15A. The generally poor activity observed shows that the basic structure cannot be altered much without destroying the activity.

Use of C-reactive protein to guide duration of empiric antibiotic therapy in suspected early neonatal sepsis

BACKGROUND

Serial C-reactive protein (CRP) measurements have been shown to be useful for guiding duration of antibiotic therapy in neonates. This study sought to determine whether this is a safe and practical approach in a developing country.

METHODS

The study was conducted at the Johannesburg Hospital between September 15, 1998, and January 15, 1999. Subjects included all neonates evaluated for suspected sepsis in the first 24 h of life who had negative initial and repeat CRP values (< or = 10 mg/l) [corrected]. Repeat CRP measurements were performed between 24 and 48 h after birth. Antibiotic therapy was stopped in these infants at 24 to 48 h, and they were observed until 72 h, when the final blood culture results were available. The number of positive blood cultures in this group was determined.

RESULTS

The repeat CRP estimation correctly identified 99 of 100 infants in the study as not requiring further antibiotic therapy (negative predictive value, 99%; 95% confidence intervals, 95.6 to 99.97%). The 1 infant with a positive blood culture was premature with a gestational age of 31 weeks. Eight babies required repeat evaluation for suspected sepsis, 4 presented on Day 3 to 4 and one of these babies died. All these neonates were of < or =33 weeks gestation.

CONCLUSION

The use of serial CRP measurements to guide antibiotic therapy is a safe and practical approach in neonates with suspected sepsis in a developing country.

Determination of histamine in tomatoes by liquid chromatography/mass spectrometry

The histamine level in tomato fruits and pastes was determined by 2 orthogonal techniques as a means of comparing accuracy. Close statistical agreement was found between assays for free histamine by capillary electrophoresis (with UV absorbance detection), and for the dansyl derivative by reversed-phase liquid chromatography (LC). Both techniques have adequate sensitivity for the analysis of endogenous histamine in tomatoes, but LC/electrospray tandem mass spectrometry was more sensitive by at least an order of magnitude, down to a level of 0.05 mg/kg.

HIV-1 co-infection in children hospitalised with tuberculosis in South Africa

SETTING

Hospitals associated with the Department of Paediatrics at the University of the Witwatersrand, Johannesburg, South Africa.

OBJECTIVES

To define the prevalence of human immunodeficiency virus (HIV) co-infection and differences in clinical presentation between HIV-infected and non-infected hospitalised children with tuberculosis.

DESIGN

Children were prospectively enrolled between August 1996 and January 1997.

RESULTS

Of 161 children enrolled, 42% were HIV-infected, including 67/137 with pulmonary tuberculosis (PTB) and 1/24 with extra-pulmonary disease (EPTB). Positive microscopy or bacteriology did not differ by HIV status for children with either PTB or EPTB. Although age did not differ between HIV-infected and non-infected children with PTB, non-HIV-infected children with EPTB were significantly older than those with PTB only (median age 32 months vs 14.5 months, P = 0.004). Chronic weight loss, malnutrition and the absence of BCG scarring were more common in HIV-infected children with PTB. HIV-infected children were also more likely to show cavitation (P = 0.001) and miliary TB (P = 0.01) on chest X-ray. Reactivity to tuberculin (> or = 5 mm and > or = 10 mm in HIV-infected and non-infected children, respectively) was significantly lower in HIV-infected children, as were CD4+ lymphocyte levels. The mortality rate during the study was 13.4% in HIV-infected children compared with 1.5% in non-HIV-infected children (P = 0.03).

CONCLUSIONS

There is a high prevalence of HIV co-infection in children with TB. Progressive PTB and death are more common in HIV-infected children. Tuberculin skin testing is of limited use in screening for TB in HIV-infected children even when using a cut-point of > or = 5 mm.