Made available in DSpace on 2014-10-09T12:23:05Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:32Z (GMT). No. of bitstreams: 1 01283.pdf: 2447147 bytes, checksum: 6203b909d0d934193ad105213a7ef253 (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Medicina, Universidade de Sao Paulo - FM/USP

M.Phil. / The record cards of all patients (21 554) examined by the eye clinic on the Phelophepa Mobile Health Care train during January and September, 1995 were analysed. The prevalence of. POAG in the sample was 0-.8% (177 of 21 554 persons). Differences in POAG prevalence were observed with respect to sex, age and geographical region. There was a significant difference (p<0.001) in the number of males (1.1%, 92 of 8113), compared to females (0.6%, 85 of 13 441) diagnosed with POAG. In persons over 40 years of age the prevalence rate was 1.2 % (166 of 14 254 persons) and in persons over 60 years the rate was 1.7% (110 of 6375 persons). The highest prevalence rate was found in the Western Cape (1.84%) and the lowest in the Eastern Cape (0.33%). POAG patients were compared to a control group to investigate the role of certain demographic, systemic and ocular factors. Risk factor analysis identified old age(> 60 years) (OR = 7.2, 95% CI = 4.4 - 11.7), geographical area (Western Cape, OR =2.5, 95% CI = 1.7 - 3.9), systolic hypertension (OR = 2.2, 95% CI = 1.3 - 3.7), diastolic perfusion pressure (< 40 mmHg, OR = 12.9, 95% CI = 4.2 - 52.9), myopia (OR = 2.7, 95% CI = 1.7 - 4.4) and elevated IOP (21 - 30 mmHg, OR = 12.6, 95% CI = 6.4 - 25.0) as significant risk factors. The effectiveness of employing certain blood pressure (BP) and intraocular pressure (TOP) variables as screening tools for glaucoma was evaluated. The systolic BP/IOP ratio was the most valid of the four tests evaluated (sensitivity = 66.0%, specificity = 98.2%, phi coefficient = 0.72). The study recommends that glaucoma screening programmes need to be developed which include sphygmomanometry as part of a battery of tests, and these programmes be targeted specifically at high risk populations (elderly, hypertensives). Further epidemiological studies are required which investigate reasons for the geographical differences found with respect to glaucoma prevalence.

Dissertation submitted in compliance with the requirements for the Masters Degree in Technology: Radiography, Technikon Natal, 2001. / The purpose of this study was to evaluate the Carbon-14 Urea Breath Test e4C-UBT) and histology for the detection of Helicobacter pylori (H pylori) in terms of cost-effectiveness and patient perceptions. It was hypothesized that the 14C_UBTwas more cost-effective and more easily tolerated than a histological analysis of a biopsy specimen obtained on endoscopy for H pylori detection / M

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Malaria represents one of the oldest documented diseases among humans and even today organisms in the genus Plasmodium kill more people than any other infectious disease, especially in tropical and subtropical areas. The four most common species which infect humans are Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malaria. Of these four species, Plasmodium falciparum and Plasmodium vivax account for 95 percent of infections globally. Microscopy has been used since early days for the diagnosis of malaria because this method is simple, does not require highly equipped facilities, and in most cases enables differentiation among the species causing malaria in humans when performed by skilled microscopy readers. However, this method has been misleading in identifying parasite species, especially in the case of low level parasitemia, a mixed parasite infection, or modification by drug treatment as well as in placental malaria. Malaria rapid diagnostic tests (RDT) have played a major role in malaria management; particularly in providing blood based diagnosis in remote locations where microscopy based diagnosis is unavailable. These diagnostic tests are fast and easy to perform and do not require electricity or specific equipment. As part of strengthening malaria diagnostics in Malawi, the Ministry of Health and Population strongly recommends the use of malaria RDT’s at all levels of the health care delivery system. However, malaria microscopy remains a gold standard test for malaria. All patients (regardless of age) with suspected uncomplicated malaria should have a confirmed diagnosis with malaria RDT before anti-malaria treatment is administered. Based on field performance evaluations that assessed performance, quality control and production capacities of the manufacturing companies of malaria RDT’s, the Ministry of Health and Population recommended two brands of Histidine Rich Protein 2 (HRP-2), RDT’s for use in Malawi. These are SD Bioline malaria Ag Pf and the New Paracheck malaria Ag Pf. All these RDT’s are able to detect only P. falciparum. However, other species have been reported to exist in the country and there is a need to find proper RDT’s which will be able to detect all other species including P. falciparum. The main aim of this study was to evaluate Paramax-3 Pf/Pv/Pan RDT (Zephyr Biomedicals, India), if used in Malawi, could be able to detect and identify the different species of Plasmodium causing malaria in Malawi. The study recruited a total of 250 adult and infants at Bwaila Hospital in Lilongwe, Malawi. Study results showed that the overall sensitivity and specificity of the Paramax-3 RDT used in the study were 100 percent and 83 percent respectively. However, it was observed that the RDT test was not able to identify the P. ovale, and in some cases, the RDT test was positive for P. falciparum when the PCR identified the species as P. ovale. No P. vivax was detected both by RDT and PCR. This study was able to detect and identify the presence of P. malaria and P. ovale in Malawi apart from the P. falciparum. There were no significant differences between microscopy results compared to both the RDT and the PCR, with 94 percent and 98 percent sensitivities of R1 and R2 compared to RDT, as well as 94 percent and 96 percent sensitivities for R1 and R2 compared to PCR respectively. Both R1 and R2 had low specificities for example, R1 had 72 percent and R2 had 80 percent compared to RDT. Comparing R1 and R2 to PCR, the sensitivities were 64.9 percent and 67.2 percent respectively. However, the readers had difficulties differentiating the different species microscopically. The history of anti-malaria treatment had no significant effect on the outcome of the results in both the RDT and PCR.

Until recently, the major portion of the study of the electrical activity of the heart has been done with the aid of electrocardiograms and vectorcardiograms. However, such information as the variation of the magnitude and angle of the heart vector with time is not directly discernible from either of these recordings. A polarcardiograph was developed by W.K.R. Park to present the plane projection of the heart vector in magnitude and angle as a continuous function of time. The polarcardiograph proved to be useful but it was not sufficiently stable. An electronic device which would be stable and at the same-time present the heart vector in three dimensions, magnitude, frontal angle and polar angle as continuous functions of time, would be useful in electrocardiographic research. The design of such a computer, the "spherical polarcardiograph", is described in this thesis. The spherical polarcardiograph, which must compute the spherical polar coordinates of points from their respective Cartesian coordinates, has been developed using analog multipliers, subtracters and adders as well as a two-phase sinusoidal voltage source and a device for generating a voltage proportional to the phase difference of two sinusoidal signals. With the exception of the third coordinate computation and the gated feedback circuitry, the system is similar to that used by Park. Automatic balancing of the circuit occurs for a short interval during the rest period of the heart. The spherical polarcardiograph has not been constructed in final form but tests on the individual units indicate that the instrument will be well within the accuracy required for normal electrocardiographic purposes. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The relationships between lateral ventricle size, smooth pursuit eye tracking, and neuropsychological test performance were investigated using a sample of 30 chronic schizophrenic inpatients. There were no significant correlations between any of the measures. Compared to a control group of normal volunteers, the schizophrenic patients showed abnormally poor eye tracking accuracy but did not show lateral ventricular enlargement. Compared to a group of age matched non-schizophrenic psychiatric patients, the schizophrenic patients were impaired on six out of ten neuropsychological tests. As there was no evidence of lateral ventricle enlargement, it is clear that eye tracking impairment and deficits on neuropsychological tests may occur independently of enlarged lateral ventricles. The absence of relationships between impairments on the neuropsychological tests and poor eye tracking is not thought to be the result of restricted performance ranges for any of the measures. The most parsimonious conclusion is that there is no relationship between eye tracking and the variety of neuropsychological functions assessed in this study. However, an alternative possibility is that the study sample was too homogeneously impaired, and a relationship between eye tracking impairment and neuropsychological deficits might emerge in a more diverse sample representative of the range of individuals currently diagnosed as schizophrenic. / Arts, Faculty of / Psychology, Department of / Graduate

The purpose of the present study was to examine whether or not luminance thresholds through static, chromatic perimetry could be used to distinguish visual threshold losses in multiple sclerosis from that of normal functioning. It was proposed that threshold losses would be greater at both the fovea and near foveal eccentricities due to the assumption that the cone system, unlike the rods, would be the most effected by MS. Twenty-two MS patients and thirty age matched normals were tested on an extensively modified version of the Fieldmaster F225 Automatic Perimeter. Thresholds were established for an achromatic, red, and blue stimulus along a 195 - 15 degree meridian. Testing was done using a 45 apostilb background, to which the subjects were preadapted prior to testing. Results indicated that there was extensive cone involvement (loss in chromatic thresholds) for the MS subjects. Significant differences existed at the fovea between normal and clinically definite subjects but not between normal and probable. Correlational analyses indicated great functional changes in retinal sensitivity for the MS patients. Similar results were obtained between MS patients with and without optic neuritis. Discriminant analyses indicated that the red filter could correctly classify 86.27% of the normals and MS patients with few false positives or negatives. Log threshold difference values between the fovea and 30 degree nasal eccentricity were used to determine a threshold value which could separate normal profiles from MS profiles. The typical "swiss cheese" defects reported in the clinical literature were found only for the achromatic and blue filters. No irregular profiles were found for the red filter. A possible theoretical model based on the results was discussed. Limitations of the study as well as possible future research were also discussed. / Arts, Faculty of / Psychology, Department of / Graduate

In the present study, the syntactic deficit of Alzheimer's patients was investigated, using an object manipulation task. Four case studies were presented, using data from test batteries devised by Caplan (pers. comm.) and the author. Subjects responded by acting out stimulus sentences presented in aural and written modes, using a set of small figurines. Responses were evaluated following criteria described by Caplan (1986, pers. comm.). Data from the four subjects were compared with each other, and with data obtained from a similar battery administered to aphasic patients. An impairment in the ability to interpret certain syntactic structures was found for all subjects, indicating that Alzheimer's patients do suffer from a syntactic comprehension deficit in the early stages of the disease. Several syntactic structures which caused errors in the responses of the Alzheimer's subjects, also caused errors for the aphasic patients, suggesting that the parsing model underlying the design of the stimuli, described by Caplan (in press) is a valid description of normal language function. Results of the present investigation are examined in relation to a model of syntactic comprehension suggested by Caplan (in press). Contradictions to hypotheses proposed are noted. The limitations and diagnostic use of the object manipulation test, are discussed. / Medicine, Faculty of / Audiology and Speech Sciences, School of / Graduate