A method is described in this study whereby dose distributions calculated by a treatment planning system (TPS) were evaluated by using dose distributions calculated with Monte Carlo (MC) simulations. The MC calculated dose data were used as a benchmark. A generic Siemens MD 2 linear accelerator was simulated with the BEAMnrc MC code to obtain beam specific dynamic variables in a phase space file (PSF) related to particle fluence in a plane at a known distance from a water phantom. Dose distributions from various field sizes were produced by simulations with the DOSXYZnrc MC code. Two datasets were produced consisting of percentage depth dose (PDD), profiles and diagonal profile data for 6 and 15MV x-ray beams. The CadPlan TPS was commissioned with these datasets for both energies. Analyses of TPS calculated dose distributions were done in a water phantom and dose distributions for various clinical cases on patient CT data. Patient CT datasets were transformed into patient CT models that were suitable for dose calculations with DOSXYZnrc. These models consisted of various media with various densities for which interaction cross section data is available. Dose distributions for a number of clinical treatment plans could be devised on both the TPS and DOSXYZnrc. These included head and neck, breast, lung, prostate, oesophagus and brain plans. Calculations on the TPS were done for the Single Pencil Beam (SPB) and in some cases the Double Pencil Beam (DPB) convolution algorithms in combination with the Batho and ETAR (Equivalent Tissue-air ratio) inhomogeneity correction algorithms. Dose distributions were normalized to the depth of maximum dose (dmax) for single fields and to the ICRU reference point in full treatment plans. The location of these points was the same for the TPS and DOSXYZnrc distributions. PDD curves, beam profiles, dose-volume histograms (DVHs) and equivalent uniform doses (EUDs) were produced to aid in the evaluation of the TPS dose calculation accuracy. Results demonstrated that the assumptions in the convolution models used to produce beam penumbra regions, especially in blocked field cases, fail to account for scattered dose contributions outside the treatment field and overestimated the dose underneath small or thin shielding blocks. The PB algorithms in combination with the inhomogeneity corrections show total disregard for lateral and longitudinal electron transport through heterogeneous media. This effect is pronounced in regions where electronic equilibrium is not found, like low density lung. This region, in combination with high density bone nearby, proved even larger discrepancies as dose absorption decreases in low density media and increases in high density media. A small 15 MV field passing through lung tissue exhibited large dose calculation errors by the PB algorithms. The dataset produced here is flexible enough to be used as a benchmark for any TPS utilizing commissioning measurements in water. This method can address commissioning results as well as any clinical situation requiring dose calculation verification.

The need to find new manners in which to combat cardiovascular disease and associated thrombotic complications, remains a high priority in industrialised countries. Even in third-world countries the implications and associated risks of these diseases are being felt more and more. The advent of the biotechnology era and employment of recombinant DNA techniques has brought about exponential advances in understanding the complex mechanisms of haemostasis, and is employed to find new ways to combat pathological thrombotic complications. The challenge is to harness the many tools and techniques produced by the ongoing biotechnology explosion, and apply them to elucidate questions still unanswered and explore areas still unknown. In this study it was illustrated that modern molecular biology techniques can be applied in many areas of thrombosis and haemostasis research. The display of cDNA libraries on the surfaces of filamentous bacteriophages was used in the search for novel antithrombotic compounds from a haematophagous insect Hippobosca rufipes. Phages displaying the cDNA libraries were panned against human a-thrombin and selected according to their binding affinity and inhibition ability. To illustrate the use of a Escherichia coli expression system, a domain of a enzyme was cloned, expressed, and the recombinant peptide isolated and refolded. ADAMTS-13 was recently identified as an important role player in the realm of von Willebrand factor activity, including primary haemostasis and pathological disorders. The second carboxy-terminal CUB domain of ADAMTS-13 was amplified from full-length cDNA, cloned into a expression vector system, and expressed as insoluble inclusion bodies in the cytoplasm of E. coli, from where it was isolated and refolded. In this study, molecular techniques were used in different phases of research into the specific activity and interactions of a particular component of the haemostatic system. This illustrated the marriage of biotechnology with fundamental medical research in an era of interdisciplinary sciences.

Includes abstract. / Includes bibliographical references. / Milk molecules such as mucins, antibodies, bactericidal enzymes like lysozymes and fatty acids that lyse bacteria, viral particles and bacterial peptides, offer anti-microbial activity in milk. Despite human breast milk being rich in anti-microbial substances, such as mucin, that protect against pathogens and viruses, it remains a significant route of HIV transmission from mother to child. ... The objectives of the study were to isolate, purify, identify and investigate the anti-HIV-1 activity of crude breast milk particularly the human milk fat globule material (MFGM) and its purified mucin components, in HIV positive patients (n = 20) compared with those who are not infected (n = 20). This study also tested the effect that heat (80°C, 10 min) might have on breast milk which might release the milk mucins and consequently have an inhibitory effect on HIV-1.

Background: PLWH have twice the chances of developing cardiovascular disease (CVD) when compared to the uninfected population. This and other NCDs are important cause of non-AIDS related mortality among PLWH, and its prevalence may increase as PLWH continue to age. Factors that may have association with the increased risk of NCDS among PLWH have been identified including the use of HAART, systemic inflammation, male gender, aging, diet, and sedentary lifestyle. The relationship between higher diet quality and a lower risk of NCDs has been reported among PLWH. Furthermore, dietary interventions have reduced the risk of NCDs among PLWH. However, studies assessing dietary intake among PLWH in South Africa are not recent and were conducted among ART-naïve participants. This dissertation contains a scoping review of literature that sought to identify the diet quality and food insecurity indices that have been used among PLWH and how these constructs are associated with the risk of developing CVD. The primary study component assessed the nutritional and health status of adults living with HIV stable on HAART attending the Heideveld CHC in Cape Town. We also investigated the association that may exist between these factors, especially diet quality, and the risks of NCDs. Methods: For this thesis, a scoping review and primary study was conducted. For the scoping review, the frameworks of Arksey and O'Malley, the Joanna Briggs Institute's (JBI) manual for conducting scoping reviews, and the Preferred Reporting Items for Systematic review and Meta Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines were used for the scoping review. The protocol was registered on OSF registries and published in BMJ Open. Extracted data were presented in tables, followed by a descriptive summary of findings. A search strategy was developed, and a preliminary MEDLINE (via PubMed) search was conducted followed by a final search on PubMed, EbscoHost, Scopus, Web of Science, and COCHRANE library databases. The findings from the scoping review were also used to refine the protocol of the cross-sectional study. The primary study was descriptive and cross-sectional including 247 adults receiving HAART from the Heideveld CHC. Eligible participants were HIV positive, on HAART for at least 1 year, aged 18 years or older, and able to communicate in English language, isiXhosa, or Afrikaans. Ethical approvals were obtained from the UCT ethics committee and the Department of Health. Data were collected using an interviewer-administered questionnaire and the patients' folder. Data were collected on socio-demographic variables, HIV infection-related information, anthropometry, biochemical, and clinical measures, as well as weight perception, satisfaction, and management goals. Other measures included dietary intake and habits, food security, physical activity, self-esteem, smoking, and alcohol intake. Data were captured using Microsoft Excel (version 2180) and analyzed using RStudio Version 1.2.5033. Appropriate statistical methods were used to summarize and describe the results. Results: A total of 31 studies were included in the scoping review after the recommended multilevel screening against the inclusion criteria. Three studies assessing food security status showed that food insecurity was high in PLWH. Six studies assessing dietary adequacy using a predefined diet quality index showed that PLWH had moderate adherence to the Healthy Eating Index (HEI) and Mediterranean Diet Score (MDS) guidelines. However, adherence to the recommendation of individual food items or nutrients was low. Other studies presented intakes of individual nutrients or food components. Two African studies were included with none using a diet quality index. The two most reported CVD risks were obesity and hypertension. The association between diet and risk of CVD reported was complex; while some studies found significant associations, some did not. In the primary study, the majority (69.9%) were females with a median age of 46 years. The median duration of infection was 12 years, the median ART duration was 10 years, and 94.7% had a suppressed viral load. One-third of the participants had comorbidities, hypertension was the most prevalent comorbidity reported, followed by dyslipidemia and diabetes. Other comorbidities reported were CVD, renal problems, and cancer. The prevalence of obesity was 40.7% while 27.6% were overweight. Based on predefined criteria, 50.0% of the participants had high blood pressure. Food insecurity was reported by 89.0% of the participants. The median intake of fruits and vegetables was 0.9 and 1.6 servings/day respectively. Habitual consumption of SSB and processed meat on average of 1.0 servings/day was reported. Mean (SD) DASH and Alternate Healthy Eating Index (aHEI) scores were 21.6 (5.1) and 41.9 (9.8) respectively. While 80.0% did not try to gain weight in the previous year, 51.0% gained weight. However, 58.0% were happy with their present weight. There were significant differences between the three BMI categories for gender (p< 0.001), level of education (p< 0.001), ever being pregnant (p=0.046), creatinine (p=0.002), systolic BP (p=0.010), relative hand grip strength (p< 0.001), PA (p<0.001), and being a smoker (p< 0.001). There was a significant difference between those who were hypertensive and those who were not for age (p< 0.001), level of education (p=0.019), and ever being pregnant (p=0.008). There was no significant association between aHEI score and BMI, as well as DASH score and hypertension. Conclusions: Findings from the scoping review suggest that the majority of PLWH are affected by food insecurity and achieve only moderate adherence to recommendations for diet quality. Few studies have used diet quality indices to assess dietary adequacy among PLWH, and the association of diet with risks of CVD is complex and needs further research. In our primary study, the prevalence of obesity and hypertension was high among the participants, and hypertension was the most prevalent comorbidity reported. The participants were mostly middle-aged females, they were on long-term ART and most of them had an undetectable viral load. The dietary habits and consumption of participants did not conform to recommendations. Obesity was more likely among females, those who had completed high school education, women who had been previously pregnant, those who were sedentary, and less likely among those who were previous and current smokers. Hypertension had a significant positive association with age. Diet quality was not significantly different among PLWH with or without comorbidities. The findings of this study emphasize the need to incorporate holistic nutrition education into HIV care at the PHC level. More nutrition-focused research is needed among PLWH in South Africa.

No description available.

Background: Kidney stone disease is a common and often debilitating disorder, yet its pathophysiology is poorly understood. This dissertation studies predisposition to kidney stone formation from diurnal variation in physiochemical and physiologic properties of urine and in response to increased fluid intake. Methods: Urine volume, flow rate and constituents were measured in multiple timed specimens from healthy volunteers in a day. Further, subjects were asked to provide specimen over a period of increased fluid intake. Results: A 24-hour specimen missed significant periods of supersaturation in individual urine samples throughout the day. Despite a significant reduction in nocturnal urine flow rate, calcium concentration as well as urine pH and divalent phosphate remained unchanged. Finally, increased water intake did not dilute urine evenly. Conclusion: Mixing multiple urine samples obscures information about periods of increased calcium phosphate precipitation risk over 24 hours. Further, increased fluid intake does not uniformly provide risk protection.

Background: Kidney stone disease is a common and often debilitating disorder, yet its pathophysiology is poorly understood. This dissertation studies predisposition to kidney stone formation from diurnal variation in physiochemical and physiologic properties of urine and in response to increased fluid intake. Methods: Urine volume, flow rate and constituents were measured in multiple timed specimens from healthy volunteers in a day. Further, subjects were asked to provide specimen over a period of increased fluid intake. Results: A 24-hour specimen missed significant periods of supersaturation in individual urine samples throughout the day. Despite a significant reduction in nocturnal urine flow rate, calcium concentration as well as urine pH and divalent phosphate remained unchanged. Finally, increased water intake did not dilute urine evenly. Conclusion: Mixing multiple urine samples obscures information about periods of increased calcium phosphate precipitation risk over 24 hours. Further, increased fluid intake does not uniformly provide risk protection.

Limitations in the clinical applicability as well as undesireable side effects of the natural antispasmodic drubs, atropine and papaverine, turned early investigators to the problem of developing a more suitable antispasmodic through synthetic procedure.

In the first half of the 20th century, the researchers in the medical sciences in Sweden were dependent on funding from private foundations. Earlier research has shown that the foundation Stiftelsen Therese och Johan Anderssons Minne was a financier of great importance especially for the 1920s until the 1950s. This paper is written with the purpose of examining how the financing has changed over time, by analyzing the foundations yearly accounts from 1931 until 1963. I will show that physiologists and chemists took a dominant position in the fight for funds. In conclusion, it seems that the fact that the colleague of teachers at Karolinska had the power to decide who to fund were an important factor for the foundations activity. The characteristics of the medical research exercised by the researchers applying for funds were not the sole factor which affected the outcome.

Today, production companies are being asked to create scenes that are almost impossible to render. To create these impossible shots with speed and quality, the industry has created render passes. In this research project, the aim is to learn and understand the fastest and most efficient methods to create 3D Medical Sciences Visualization. A deeper understanding of Render Passes using Nuke compositing software in an industry based pipeline will answer the above statement. This project was developed in collaboration with the Uppsala Biomedical Center (BMC) and the Special Effects company Oddville. The final animation will also be used for BMC medical conferences. The results revealed that the render passes did allowed for the animation in postproduction and also saved a great deal of time.