Patterns of referral to Red Cross War Memorial Children's Hospital, Cape Town

Patterns of referral to Red Cross War Memorial Children's Hospital were studied to assess the appropriateness of referrals. From 1 July to 31 December 1987 all 9288 referral letters presented to the hospital were collected and a sample (4662 letters) analysed. It emerged that the patients were similar to those attending the outpatient department without referral, except that relatively fewer referred patients were black. The private sector, i.e. general practitioners, was the largest referral agency, followed by day hospitals. Most patients were referred to the outpatient department without an appointment. Of the specialist clinics, the surgical clinics (i.e. ophthalmology and ear, nose and throat) had the highest number of referrals. The majority of patients (84,9%) were not admitted. Only in 30,3% of referred cases did the hospital make contact with referral agents. Referral rates were highest from the predominantly coloured areas of the Cape Peninsula. The hospital cannot isolate itse" from the community it serves and needs to support and guide referral agents in order to improve the utilisation of the hospital. Training of health professionals in order to increase expertise is a priority. A study of the total patient population would facilitate the understanding of hospital utilisation. Similar studies could be beneficial at other hospitals

A comparison of cointegration and copula asset allocation approaches

The empirical performance of cointegration and copula asset allocation techniques are compared against that of the market. Multivariate copula structures are used to derive index-tracking portfolios which are then compared with that of portfolios constructed using cointegration techniques. The results suggest that modelling the long-term relationships between stocks by means of the cointegration approach do not consistently lead to portfolios that outperform the benchmark. Using a short-term asset allocation approach, such as the copula-simulation approach, lead to portfolios that perform at least as well as the cointegration portfolios

Shallow-water spinal injuries – devastating but preventable

Background. Shallow-water diving injuries have devastating consequences for patients and their families, requiring intensive use of resources in both the acute and rehabilitative phases of injury. With the final clinical outcome often poor, the question is raised as to whether a target group can be identified for whom to implement a preventive programme. Objective. To evaluate the demographics, clinical features and outcomes of shallow-water diving injuries in an acute spinal cord injury (ASCI) unit. Materials and methods. All patients admitted to the ASCI unit with diving-related injuries were entered into the study. Data regarding demographics, injury profile and subsequent management were collated. All case notes and X-rays were reviewed. Ethical approval was obtained. Results. Forty-six patients were reviewed from 19 April 2003 to 8 February 2009. A steady annual increase in diving injuries was noted. A very specific patient profile was identified: 91% male incidence, average age 23 years, 37% admitted alcohol use, with a summer-time prevalence. Compression-flexion type injuries were most prevalent, with an orthopaedic level of C5 and neurological level of C4 being the most common injury sites. A third of diving injuries occurred in the sea, 20% in swimming pools, 20% in rivers, 11% in tidal pools and 4% in dams. Conclusion. A very specific patient profile was identified, and the severity of shallow-water diving injuries was confirmed. No current preventive programme exists except for a single television advertisement. These data will be used to motivate further educational and preventive programmes for reducing the incidence of diving-related injuries

Multiple sclerosis in South Africa

Since there are no well-documented epidemiological studies on multiple sclerosis (MS) in South Africa, we devised a questionnaire to determine qualitative data. Responses were obtained from 430 patients: 91% had magnetic resonance imaging (MRI) scans, 64% had lumbar punctures and 49% had evoked potentials to establish the diagnosis of MS. A total of 71% of the respondents were aged 30 - 59 years, 73% were female, and 89% were white. In terms of MS type, 46% had relapsing-remitting MS, 13 % secondary progressive MS, 12% primary progressive MS, 12% benign MS, and 17% not known. Disease-modifying treatment was not used by 32% of respondents, and 30% were treated with methotrexate and 22% with interferon beta. These findings are similar to those in the literature, except for the under-utilisation of interferons as disease-modifying treatment. South African Medical Journal Vol. 98 (5) 2008 pp. 391-39

The areca nut chewing habit and oral squamous cell carcinoma in South African Indians

A retrospective study (1983 - 1989) of oral squamous carcinomas and concomitant oral habits was undertaken in South African Indians from Natal. Information came from hospital records and interviews with patients, famlilies and friends. There were 143 oral squamous carcinomas; these occurred in a ratio of 1:1,6 for men and women respectively. Squamous carcinomas of the cheek (buccal mucosa, alveolar sulcus and gingiva) occurred most frequently, especially in women (57/89 - 64%), while in men tongue cancer predominated (22/54 - 41-%). Ninety-three per cent of women (83/87) and 17% of men (9/54) habitually chewed the areca nut. Thirty-nine of 57 women (68%) with cheek cancer and 21/25 (84%) with tongue cancer only chewed the nut (no tobacco, snuff or smoking). Analyses confinned an association between nut chewing and cheek cancer. The odds ratio (OR) for oral cancer in women 25 years and older who only chewed the nut was 43,9 and the attributable risk (AR) 0,89 (89%). With tobacco the OR increases to 47,42 and the AR to 0,91 (91%). The data showed that the areca nut habit with or without tobacco use is important in the development of oral squamous carcinoma. Elimination of this habit can reduce the risk in these women substantially (89 - 91%) if all other factors remain the same

Angular dependence of the magnetic-field driven superconductor-insulator transition in thin films of amorphous indium-oxide

A significant anisotropy of the magnetic-field driven superconductor-insulator transition is observed in thin films of amorphous indium-oxide. The anisotropy is largest for more disordered films which have a lower transition field. At higher magnetic field the anisotropy reduces and even changes sign beyond a sample specific and temperature independent magnetic field value. The data are consistent with the existence of more that one mechanism affecting transport at high magnetic fields.Comment: 4 pages, 5 figure

Additive opportunistic capture explains group hunting benefits in African wild dogs

African wild dogs (Lycaon pictus) are described as highly collaborative endurance pursuit hunters based on observations derived primarily from the grass plains of East Africa. However, the remaining population of this endangered species mainly occupies mixed woodland savannah where hunting strategies appear to differ from those previously described. We used high-resolution GPS and inertial technology to record fine-scale movement of all members of a single pack of six adult African wild dogs in northern Botswana. The dogs used multiple short-distance hunting attempts with a low individual kill rate (15.5%), but high group feeding rate due to the sharing of prey. Use of high-level cooperative chase strategies (coordination and collaboration) was not recorded. In the mixed woodland habitats typical of their current range, simultaneous, opportunistic, short-distance chasing by dogs pursuing multiple prey (rather than long collaborative pursuits of single prey by multiple individuals) could be the key to their relative success in these habitats

Determination of kanamycin plasma levels using LC-MS and its pharmacokinetics in patients with multidrug-resistant tuberculosis with and without HIV-infection

The objectives of the study were: (1) to determine kanamycin plasma concentrations using liquid chromatography coupled with mass spectrometry (LC-MS), (2) to investigate kanamycin pharmacokinetics (PK) in patients with multi-drug resistant tuberculosis (MDR-TB), (3) to find out whether HIV infection, kidney dysfunction and antiretroviral drugs influence kanamycin PK. The study was designed as a non-randomized study involving male and female HIV- positive and HIVnegative patients admitted for MDR-TB treatment. Blood samples were collected before (baseline) and ½, 1, 2, 4, 8 and 24 hours after intramuscular injection of kanamycin. LC-MS was used to quantify kanamycin plasma concentrations. Thirty one patients including 13 HIV (+) participated in the study. The lower limit of detection and lower limit of quantification of kanamycin were 0.06 μg/ml and 0.15 μg/ml respectively. Kanamycin PK parameters were described and there was no significant difference between HIV-positive and HIV-negative patients. A statistical significant difference (p=0.0126) was found in the renal function in HIV - positive and HIV - negative patients. However, this difference did not affect kanamycin elimination. No interactions have been identified between antiretroviral drugs and kanamycin. Conclusion: LC-MS analysis method is highly specific and highly sensitive in the detection and quantification of kanamycin plasma concentrations. Kanamycin PK in patients with MDR-TB was described. Due to a limited number of patients, we cannot rule out any influence of HIV - infection, renal impairment and antiretroviral drugs on kanamycin pharmacokinetics. The relationship between the area under the curve of kanamycin free plasma concentrations (fAUC) and its minimum inhibitory concentrations (MIC) on M.tuberculosis isolated from the sputum of each patient should be assessed. Therefore, kanamycin free plasma concentrations and MIC should be determined.Web of Scienc

Mass spectrometry metabolomics and feature-based molecular networking reveals population-specific chemistry in some species of the Sceletium genus

The Sceletium genus has been of medicinal importance in southern Africa for millennia and Sceletium tortuosum (Aizoaceae), one of eight species in the genus has gained pharmaceutical importance as an anxiolytic and anti-depressant due to the presence of mesembrine alkaloids. S. tortuosum is used for the manufacture of herbal teas, dietary supplements and other phytopharmaceutical products. This study aimed to provide a metabolomic characterization of S. tortuosum and its sister species as these are not easy to distinguish using morphology alone. Plant samples were thus collected from various locations in the succulent Karoo (South Africa) and analyzed through liquid chromatography-mass spectrometry (LC-MS), using MSE fragmentation as a putative tool for chemical identities. Metabolomics-based analyses in combination with molecular networking were able to distinguish between the four species of Sceletium based on the presence of 4-(3,4-dimethyoxyphenyl)-4-[2-acetylmethlamino)ethyl]cyclohexanone (m/z 334.2020; RT 6.60 min), mesembrine (m/z 290.1757; RT 5.10 min) and 4’-O-demethylmesembrenol (m/z 276.1597; RT 4.17 min). Metabolomic profiles varied according to the different localities and metabolites occurred at variable quantitative levels in Sceletium ecotypes. Molecular networking provided the added advantage of being able to observe mesembrine alkaloid isomers and coeluting metabolites (from the joubertiamine group) that were difficult to discern without this application. By combining high-throughput metabolomics together with global and feature basedmolecular networking, a powerful metabolite profiling platform that is able to discern chemical patterns within and between populations was established. These techniques were able to reveal chemotaxonomic relationships and allowed for the discovery of chemical markers that may be used as part of monitoring protocols during the manufacture of phytopharmaceutical and dietary products based on Sceletium.The National Research Foundation of South Africa and Medical Research Council (South Africa).http://frontiersin.org/Nutritiondm2022Plant Production and Soil Scienc

A time-frequency analysis approach for condition monitoring of a wind turbine gearbox under varying load conditions

This paper deals with the condition monitoring of wind turbine gearboxes under varying operating conditions. Generally, gearbox systems include nonlinearities so a simplified nonlinear gear model is developed, on which the time–frequency analysis method proposed is first applied for the easiest understanding of the challenges faced. The effect of varying loads is examined in the simulations and later on in real wind turbine gearbox experimental data. The Empirical Mode Decomposition (EMD) method is used to decompose the vibration signals into meaningful signal components associated with specific frequency bands of the signal. The mode mixing problem of the EMD is examined in the simulation part and the results in that part of the paper suggest that further research might be of interest in condition monitoring terms. For the amplitude–frequency demodulation of the signal components produced, the Hilbert Transform (HT) is used as a standard method. In addition, the Teager–Kaiser energy operator (TKEO), combined with an energy separation algorithm, is a recent alternative method, the performance of which is tested in the paper too. The results show that the TKEO approach is a promising alternative to the HT, since it can improve the estimation of the instantaneous spectral characteristics of the vibration data under certain conditions