Non-invasive cardiac output monitoring with electrical velocimetry after cardiac surgery in infants.

INTRODUCTION: Low cardiac output following cardiac surgery is a major determinant of outcome that may be improved by early detection, yet there are no widely accepted methods for its measurement in young children. We evaluated the feasibility of the routine use of electrical velocimetry, a non-invasive technique providing continuous measurement of cardiac output, in infants in the early postoperative period. METHODS: With ethical approval and parental consent, infants undergoing cardiac surgery were recruited. The ICON electrical velocimetry monitor was attached on admission to the intensive care unit (ICU) and remained for up to 24h. RESULTS: A total of 15 infants were recruited, median age 3 months (interquartile range (IQR) 0.5-7.5) and weight 4.8kg (IQR 3.9-7.1), undergoing various operations. Cardiac index had a weak correlation with arterial lactate (r=-0.24, p=0.02) and no correlation with blood pressure, central venous pressure or arteriovenous oxygen difference. Data were recorded for a median of 19h (range 5-24), with lead detachment or movement artefact the most common causes of data loss. There was marked minute-to-minute variability, with 25% of consecutive measurements having >5% variability. CONCLUSION: Cardiac index measured by electrical velocimetry in infants in the early postoperative period is impaired by frequent data loss and marked intrapatient variability. Our feasibility study suggests that it is unsuitable for use as a routine monitoring tool in the setting of postsurgical ICU care.

Diminishing returns drive altruists to help extended family.

Altruism between close relatives can be easily explained. However, paradoxes arise when organisms divert altruism towards more distantly related recipients. In some social insects, workers drift extensively between colonies and help raise less related foreign brood, seemingly reducing inclusive fitness. Since being highlighted by W. D. Hamilton, three hypotheses (bet hedging, indirect reciprocity and diminishing returns to cooperation) have been proposed for this surprising behaviour. Here, using inclusive fitness theory, we show that bet hedging and indirect reciprocity could only drive cooperative drifting under improbable conditions. However, diminishing returns to cooperation create a simple context in which sharing workers is adaptive. Using a longitudinal dataset comprising over a quarter of a million nest cell observations, we quantify cooperative payoffs in the Neotropical wasp Polistes canadensis, for which drifting occurs at high levels. As the worker-to-brood ratio rises in a worker's home colony, the predicted marginal benefit of a worker for expected colony productivity diminishes. Helping related colonies can allow effort to be focused on related brood that are more in need of care. Finally, we use simulations to show that cooperative drifting evolves under diminishing returns when dispersal is local, allowing altruists to focus their efforts on related recipients. Our results indicate the power of nonlinear fitness effects to shape social organization, and suggest that models of eusocial evolution should be extended to include neglected social interactions within colony networks.

Capture of farmed Nile crocodiles (Crocodylus niloticus): comparison of physiological parameters after manual capture and after capture with electrical stunning.

The electric stunner (e-stunner) is commonly used to handle Nile crocodiles (Crocodylus niloticus) on commercial farms in South Africa, but while it seems to improve handling and safety for the keepers, no information regarding physiological reactions to e-stunning is currently available. The aim of this study was therefore to compare various physiological parameters in farmed C niloticus captured either manually (noosing) or by using an e-stunner. A total of 45 crocodiles were captured at a South African farm by either e-stunning or noosing, and blood samples were taken immediately as well as four hours after capture. Parameters monitored were serum corticosterone, lactate, glucose, as well as alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase and creatine kinase. Lactate concentrations were significantly higher in noosed compared with e-stunned animals (P<0.001). No other blood parameter differed significantly between the two methods of capture. In addition, recorded capture time confirmed that noosing takes significantly longer time compared with e-stunning (P<0.001), overall indicating that e-stunning seems to be the better option for restraint of especially large numbers of crocodiles in a commercial setup because it is quicker, safer and did not cause a significant increase in any of the parameters measured.

Self-reported musculoskeletal pain among dentists in South Africa: A 12-month prevalence study.

INTRODUCTION: Musculoskeletal trouble (ache, pain, discomfort) originating in the neck, shoulder, and back is a common occupational hazard among dental professionals worldwide, The significance of this problem justified research into the prevalence of these symptoms among dentists in South Africa for which there is currently no information. AIMS: The aim of this study was to investigate the one-year prevalence of self-reported musculoskeletal trouble in the neck, shoulder, and lower back areas among dentists in South Africa. METHODS: A survey questionnaire was forwarded to all members of the South African Dental Association whose email addresses were recorded on the Association data base. The email survey was performed using the previously validated Nordic Musculoskeletal Questionnaires. RESULTS: This cross sectional study revealed a self-reported 12-month prevalence of musculoskeletal trouble (ache, pain, discomfort) among dentists in South Africa of 77.9% involving the neck, 69.8% the lower back, and 72.4% the shoulders, Multiple regression analysis showed that a

Smoking after cardiac transplantation.

Although smoking cessation is a prerequisite prior to listing for cardiac transplantation, some patients return to smoking after recovery. We have covertly assessed the smoking habits of our cardiac transplant recipients (with ethical approval) since 1993 by measuring urinary cotinine: a level of >500 ng/mL signifying continued tobacco use. We retrospectively analyzed survival, causes of death and the development of graft coronary artery disease (GCAD) with respect to the number of positive and negative cotinine levels. One hundred four of 380 (27.4%) patients tested positive for active smoking at some point posttransplant, and 57 (15.0%) tested positive repeatedly. Smokers suffered significantly more deaths due to GCAD (21.2% vs. 12.3%, p < 0.05), and due to malignancy (16.3% vs. 5.8%, p < 0.001). In univariate analysis, smoking after heart transplantation shortened median survival from 16.28 years to 11.89 years. After correcting for the effects of pretransplant smoking in time-dependent multivariate analysis, posttransplant smoking remained the most significant determinant of overall mortality (p < 0.00001). We conclude that tobacco smoking after cardiac transplantation significantly impacts survival by accelerating the development of graft vasculopathy and malignancy. We hope that this information will deter cardiac transplant recipients from relapsing, and intensify efforts in improving cessation rates.

Clinical experience with assisted venous drainage cardiopulmonary bypass in elective cardiac reoperations.

Reoperative cardiac surgery is associated with substantial morbidity and mortality due to technical problems at sternal reentry, which can result in laceration of the right ventricle, innominate vein injury, or embolization from patent grafts. To minimize the risk associated with reentry, we adopted the method of assisted venous drainage in the cardiopulmonary bypass circuit with peripheral cannulation for cardiac reoperations. From March 1999 to May 2003, a series of 52 patients (38 males; mean age 48.7 years, range 4 months to 78 years) underwent cardiac reoperations performed with centrifugal pump venous-assisted cardiopulmonary bypass. EuroSCORE was 7.34 +/- 3.9 (range, 4-19). The reoperations were coronary artery bypass graft (25 patients), valve replacement/repair (18 patients), and complex pediatric procedures (11 patients). The studied adverse events were structural damage at reentry, mortality, blood loss, stroke, and hemolysis. Complications at sternotomy were damage to the innominate vein (1 patient) and aorta (1 patient) with blood loss of 625 and 225 mL, respectively. Four patients required intraaortic balloon pump or extracorporeal membrane oxygenation (n = 1) for hemodynamic support on weaning off cardiopulmonary bypass. Three patients died in the postoperative period. Our experience with centrifugal pump-assisted venous drainage in cardiac reoperations has shown excellent results, with reduced risk of damage to vital structures on sternal reentry. In cases in which structural damage did occur, blood loss was minimal.

A literature review and pilot study to characterise the treatment of burning mouth syndrome.

Although the definition of burning mouth syndrome (BMS) can vary, the most commonly accepted is that of a burning sensation of normal appearing oral mucosa with no apparent underlying local or systemic contributing factors. The condition can be classified according to the patterns of burning experienced, the severity of the burning, as well as the pattern of onset. The management of these patients is difficult, since they are often seen by numerous clinicians and many unnecessary tests are performed in the hope of finding an underlying physical cause for the burning. No precise information pertaining to the natural history of BMS could be found. This paper consists of a selective review of the literature on BMS as well as a pilot study involving the standardised collection of data on 10 patients (9 women and 1 man) with BMS. These patients will be followed up in the long term in order to gather information pertaining to the natural history of this condition. No detectable local or systemic cause for the burning sensation could be found for any of the 10 subjects. The role of somatisation as a mechanism for burning sensation was investigated and certain proposals have been put forward regarding the management of such patients.

Nutritional status of preschool children in informal settlement areas near Bloemfontein, South Africa.

OBJECTIVE: To determine the nutritional status and household resources of preschool children. DESIGN: A cross-sectional survey. SETTING: : Two informal settlement areas, Joe Slovo (JS) and JB Mafora (JBM) in Mangaung, near Bloemfontein, South Africa. SUBJECTS: Preschool children (<72 months) of a randomly selected sample of households in JS (experimental) (n = 162) and JBM (control) (n = 186) were included. Standard methods were used to obtain household and care-giver particulars, weight and height measurements, blood and stool samples, and 24-hour dietary recalls. RESULTS: Breast-feeding and dietary intake in the two areas were nearly similar; breast-feeding was continued for 12 months and longer. Although the children's total protein intake was sufficient, their energy intake was low. A low median intake of micronutrients prevailed, including iron, zinc, calcium, niacin, riboflavin, thiamine and vitamins C, B6, A and D. The prevalence of being underweight (JS = 19.8%; JBM = 18.8%), stunted (JS = 29%; JBM = 21. 5%) and wasted (JS = 6.5%; JBM = 3.7%) were fairly similar in both areas, as well as the prevalence of marginal vitamin A deficiency, anaemia, iron deficiency and parasite infestations. No significant associations could be found between household and nutritional status indicators, probably due to the small number of well-nourished children and the generally poor household situation of the participants. CONCLUSIONS: The generally poor nutritional status and environmental conditions emphasize the urgency of intervention for these children.

The diagnosis of skeletal tuberculosis by polymerase chain reaction.

OBJECTIVE: To determine the potential of the polymerase chain reaction (PCR) for detecting Mycobacterium tuberculosis in skeletal samples by comparing results obtained by 1) Ziehl Neelsen staining, Lowenstein-Jensen and Bactec culture, 2) histopathology and clinical findings at the level of agreement, sensitivity and specificity. DESIGN: Cross sectional study. SETTING: Department of Medical Microbiology, Orthopaedics and Anatomical pathology, University of the Orange Free State Bloemfontein, South Africa. SUBJECTS: 45 consecutive patients were extensively investigated, 30 patients with clinical presumptive active tuberculosis and 15 with other pathology. RESULTS: Detection using culture could confirm only three of the 26 clinically diagnosed tuberculosis cases while PCR detection confirmed disease in 15 cases. The use of PCR increased the confirmation of clinically probable tuberculosis from 14 using standard laboratory techniques and histology to 18 of 26 cases. Calculated sensitivity and specificity for PCR employing culture as the "gold standard" were 100% (with 95% CI 29.2; 100.0) and 71.4% (55.4; 84.3), which due to low detection levels, basically excludes culture as a standard for statistical analysis. Sensitivity and specificity for PCR using histology as the "gold standard" were 78.6% (49.2; 95.3) and 87.1% (70.2; 96.4) respectively with positive and negative predictive values of 73.3% (44.9; 92.2) and 90% (73.5; 97.9) respectively. Positive agreement between PCR and histology was 0.64 (0.4; 0.9) indicating fair agreement. CONCLUSION: Although numbers in the study were too low to effectively draw statistically valid conclusions the importance of the relevance of PCR for rapid detection of low numbers of acid-fast bacilli and confirmation of mycobacterial infection in spinal biopsies has been established.

Comparative activity of eighteen antimicrobial agents against anaerobic bacteria isolated in South Africa.

The in vitro activity of 18 antimicrobial agents was determined against 378 anaerobic bacteria isolated in Bloemfontein, South Africa, during 1996/97. Against the gram-positive isolates, MICs of penicillin and cefoxitin were >0.5 microg/ml and >16 microg/ml, respectively, for five and three strains of non-perfringens Clostridium spp. Seventeen Peptostreptococcus anaerobius strains were resistant to penicillin (MIC > or = 2 microg/ml). All gram-positive anaerobes tested except one Peptostreptococcus sp. and one Clostridium sp. were susceptible to dalfopristin-quinupristin (MICs < or = 1 microg/ml). The carbapenems exhibited excellent activity against the gram-positive isolates and were effective against most gram-negative anaerobes, with the exception of the fusobacteria. Only seven strains exhibited decreased susceptibility to trovafloxacin (MICs > 2 microg/ml). In mixed anaerobic/aerobic infections, carbapenems and the fourth-generation quinolone trovafloxacin were the agents most suitable for us as broad-spectrum monotherapy.

Oral lipoid proteinosis.

This literature review of oral lipoid proteinosis and a case report of an infant with this condition describe an uncommon condition inherited as an autosomal recessive trait, but one which is more likely to occur in this country than elsewhere. The article discusses other lesions which could be mistaken for oral lipoid proteinosis, and offers some pertinent aspects of its diagnosis and management.

In vitro activities of 15 antimicrobial agents against clinical isolates of South African enterococci.

The activities of a panel of currently available antibiotics and the investigational agents LY 333328, linezolid, CL 331,002, CL 329,998, moxifloxacin (BAY 12-8039), trovafloxacin, and quinupristin-dalfopristin against 274 clinical isolates of enterococci were determined. No vancomycin resistance or beta-lactamase production was observed. Except for 12 isolates (all non-Enterococcus faecalis) showing reduced susceptibility to quinupristin-dalfopristin (MIC, >/=4 microg/ml), the new agents exhibited promising in vitro antienterococcal activity.

Enterococcal endocarditis--a case treated with teicoplanin and amoxycillin.

The study aimed to determine the antibacterial therapy effective in the cure of endocarditis caused by Enterococcus faecalis resistant to clinically achievable levels of vancomycin. Isolation of the causative enterococcus had been achieved by direct inoculation of the resected valve into the culture medium in theatre. The patient was known to have had an aortic valve defect since childhood and had recently undergone splenectomy following trauma. Blood cultures were negative prior to valve replacement. A perivalvular abscess was noted at operation. In vitro minimal bactericidal results and serum activity were the basis of the postoperative choice of drugs. The minimal bactericidal level of teicoplanin was 250 micrograms/ml and that of amoxycillin 64 micrograms/ml. Neither is achievable with the advocated dosage. A combination of these two cell-wall-active agents successfully eliminated the infection. Acting at two different sites in the synthesis of the bacterial cell wall, teicoplanin and amoxycillin were found to be bactericidal in vitro at the trough levels of the antibiotics in the serum. The patient recovered fully.

Plasmid analysis of Neisseria gonorrhoeae isolates and dissemination of tetM genes in southern Africa 1993-1995.

One group (145 isolates) of Neisseria gonorrhoeae was collected from municipal clinics in Bloemfontein in 1994 and a second group (65 isolates) in 1995. Penicillin and tetracycline MICs were determined and plasmid analysis performed to monitor antimicrobial susceptibilities in conjunction with the occurrence of plasmids in these isolates. The prevalence of penicillin resistance caused by beta-lactamase plasmids remained constant at 9% during the study period. Three high-level tetracycline-resistant strains (MICs 16 mg/L), the first to be detected in South Africa, were isolated in 1994. Although there was a reduction in the percentage of isolates harbouring 24.5 MDa conjugative plasmids (from 79% in 1994 to 46% in 1995), this was partially counteracted by an increase in TetM-encoding conjugative plasmids (25.2 MDa) from 2% to 18.5%. The tetM genes of 13 isolates shown to exhibit high-level tetracycline resistance were characterized as the American type. The American-type tetracycline resistance plasmid was demonstrated in 11 isolates. Digestion with Bg/l showed that two isolates harboured tetM-encoding plasmids that differed from the American- and Dutch-type plasmids described previously: one isolate contained a plasmid that produced two fragments of different sizes from those of the American-type plasmid and the second isolate possessed an American/Dutch hybrid plasmid. Auxotyping/serotyping and random amplified polymorphic DNA analysis revealed a predominant tetracycline-resistant family (NR/IA-6, genomic group I) in Bloemfontein. As there is a high incidence of chlamydial infections in southern Africa requiring tetracycline therapy, selective pressures exist in the environment for the maintenance and rapid spread of high-level tetracycline-resistant N. gonorrhoeae. It is possible that tetM genes may have emanated from Botswana and/or Namibia to Bloemfontein. The establishment of high-level tetracycline-resistant N. gonorrhoeae in Bloemfontein was seen to be complex as a related group of strains was identified, plasmid dissemination was evident and two new TetM-encoding plasmids were demonstrated. The appearance of these TetM-encoding plasmids indicates either that the American- and Dutch-type plasmids are continuing to evolve or that tetM genes are being introduced into different families of 24.5 MDa conjugative plasmids.