Showing items 361 - 376 of 376

Vitamin E supplementation and secondary metabolites interactions and effects on melanoma growth

- Ottino, Paulo

  • Authors: Ottino, Paulo
  • Date: 1997
  • Subjects: Vitamin E Melanoma
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4016 , http://hdl.handle.net/10962/d1004076
  • Description: The present study was undertaken to determine the effects and possible mechanism of action of vitamin E succinate on malignant murine melanoma (BL6) and non-malignant monkey kidney (LLCMK) cell growth in vitro. Studies revealed that supplementation of 5, 7 and lOJLg/ml vitamin E succinate significantly inhibited BL6 cell growth, while in LLCMK cells no significant increase or decrease in growth was observed. The actual mechanism by which vitamin E succinate inhibits BL6 cell growth is at present unclear. Studies have suggested a radical or oxidant involvement in a number of degenerative diseases such as cancer, and that supplementation of antioxidant vitamins such as vitamin E may function to reduce cancer cell growth by quenching free radical species and preventing lipid peroxidation. In addition to its antioxidant role in a cell, vitamin E is believed to modulate the activities of various enzymes and metabolites in the eicosanoid pathway. Hence, this study investigated the effects of vitamin E succinate supplementation on free radical and lipid peroxidation levels, as well as the activities of various enzymes and metabolites ill the eicosanoid pathway. Throughout this study, emphasis was placed on BL6 melanoma cells since the magnitude of the relationship between LLCMK growth and the levels of various enzymes and metabolites in the eicosanoid pathway varied considerably from one experiment to another and did not show the consistent trend found with the BL6 cells. A decrease in cell growth was found to be accompanied by a concomitant increase rather than a decrease in the levels of free radicals and lipid peroxidation, suggesting that the growth inhibitory effects of vitamin E succinate on BL6 cells in vitro was not due to its antioxidant properties associated with the vitamin E component, but rather due to one or more of its other potential roles within the cell. This proposal was further strengthened by findings that vitamin E succinate, a non-physiological antioxidant in its esterified form, did not undergo significant cleavage to free vitamin E in the BL6 cells. Vitamin E succinate is believed to modulate membrane bound enzyme activities through physicochemical interactions with membrane lipids and changes in membrane fluidity. Hence, this study investigated the role of vitamin E succinate in modulating the activity of various enzymes and secondary messengers in the eicosanoid pathway. Supplementation of l-lOjLg/ml vitamin E succinate resulted in an overall increase in phospholipase A2 activity while cyclooxygenase and adenyl ate cyclase activities were found to be significantly increased at vitamin E succinate concentrations of 7 and WjLg/ml respectively. A significant increase in" 5-LOX activity was observed a! 10jLg/mi supplementation. The suggestion that vitamin E succinate modulates membrane bound enzyme activities was further strengthened by uptake and cellular distribution studies, which showed significantly higher levels of vitamin E succinate in membrane fractions of BL6 cells when compared with stroma fractions. Another factor which could account for elevated PLA2,-5-LOX and COX activities in BL6 cells as a result of vitamin E succinate supplementation, was that of intracellular calcium levels. Supplementation of BL6 cells with 1-7 jLg/ml vitamin E succinate resulted in an overall increase in intracellular calcium levels. These changes in calcium levels however were positively correlated with changes in PLA2 activity only. Since the rate of prostaglandin synthesis is controlled by phospholipase A2 activity, and net prostagiandin production is dependant on cyclooxygenase activity, the effects of vitamin E succinate supplementation on prostaglandin levels in BL6 cells was determined. Vitamin E succinate supplementation resulted in a significant decrease in prostaglandin D2 levels at vitamin E succinate concentrations of 3, 5, 7 and lOjLg/ml respectively, while prostaglandin F2a levels were significantly decreased at 1-10jLg/ml vitamin E succinate. The increases in prostaglandin E2 and 12 levels were inversely related to BL6 cell growth suggesting that both prostaglandins may act as negative regulators of BL6 cell growth. When comparing prostaglandin E2 levels to prostaglandin 12 levels in BL6 cells, significantly higher levels of prostaglandin E2 were found, suggesting that vitamin E succinate effects were mediated primarily through an increase in prostaglandin E2 levels. Furthermore, prostaglandin E2 levels are believed to modulate adenylate cyclase activity. It is therefore reasonable to conclude that the increased adenyl ate cyclase activity found in BL6 cells was dependant on prostaglandin E2 levels, since increases in prostaglandin E2 levels at 7 and lOjLg/ml vitamin E succinate correlated with an increase in adenylate cyclase activity and cyclic adenosine monophosphate levels. Thus it appeared that the observed inhibitory effects of vitamin E succinate supplementation on BL6 cell growth was not due to the antioxidant properties associated with the vitamin E component of the vitamin E succinate molecule, but was rather mediated in part through a cascade effect initiated by phospholipase A2 activation and archidonic acid release. This initial effect then appeared to result in an increase in cyclooxygenase activity and activation of a prostaglandin E2-adenylate cyclase-cyclic adenosine monophosphate linked system, ultimately altering cyclic adenosine monophosphate levels and inhibiting BL6 cell growth. This was confirmed when BL6 cells were supplemented with indomethacin, a cyclooxygenase inhibitor. Supplementation with the inhibitor resulted in vitamin E succinate having no inhibitory effects on BL6 cell growth. Furthermore, when comparing the levels of prostaglandin ~, adenylate cyclase activity and cyclIC adenosine monophosphate in the indomethacin treated cultures to non-indomethacin treated cultures, markedly lower levels of these metabolites were found in the indomethacin treated cultures. The cause of the increase in free radical and lipid peroxidation levels in BL6 cells following vitamin E succinate supplementation was further investigated. Cyclooxygenase enzymes are believed to generate free radical species and contribute to lipid peroxidation levels during catalytic activity. Markedly lower levels of free radicals and lipid peroxidation in indomethacin treated cultures were found when compared with vitamin E succinate treated cultures alone, suggesting that the increases in free radical and lipid peroxidation levels in BL6 cells supplemented with vitamin E succinate were indirectly due to an increase in cyclooxygenase activity in these cells.
  • Full Text:
  • Date Issued: 1997

Voices of the Transport and Omnibus Workers Union Vol 1 No 9

- TOWU

  • Authors: TOWU
  • Date: Dec 1997
  • Subjects: TOWU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/135587 , vital:37278
  • Description: NACTU held its 5th National Congress at Shaft 17 centre in Gauteng from 13 to 16th November 1997. Comrades M Soeker, Joe Sineker, J Braaf, C Lahoo and D Abels were the TOWU delegates. Several constructive resolutions were passed at Congress, notably: Organizational issues Labour market issues Economic issues Social issues Transformation and affirmative action. Discussion and debates ensured that everybody present partook actively because making resolutions and implementing them .are two different things. Message of NACTU President, Comrade James T Madlalose: "We in NACTU need to be more committed and focused. A lot of work lies ahead and it is our responsibility as Congress to execute it with the best interests of our members in mind. NACTU will survive AMANDLA!".
  • Full Text:
  • Date Issued: Dec 1997

Voltammetric behavior of cysteine and metallothionein on cobalt (II) tetrasulfonated phthalocyanine modified glassy carbon electrodes

- Limson, Janice, Nyokong, Tebello

  • Authors: Limson, Janice , Nyokong, Tebello
  • Date: 1997
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/293346 , vital:57077 , xlink:href="https://doi.org/10.1002/elan.1140090314"
  • Description: Cysteine, and rat Cd, Zn-metallothionein (Cd, Zn-MT) have been studied electrochemically at glassy carbon electrodes modified with cobalt(II) tetrasulfonated phthalocyanine, [CoIITSPc]4−, where Pc(2-) = phthalocyanine dianion. The electrode was modified by electrodeposition of [CoIITSPc]4−. The anodic currents for the oxidation of cysteine on these electrodes are observed at 0.82 V (vs. Ag/AgCl) in acidic media. The anodic currents for the oxidation of Cd, Zn-MT are observed at 0.90 V at pH 8.4 (Tris buffer).
  • Full Text:
  • Date Issued: 1997

Walton Park garden

- Skead, C J (Cuthbert John)

Walton Park garden

- Skead, C J (Cuthbert John)

Walton Park garden

- Skead, C J (Cuthbert John)

WCED causes crisis in education

- SADTU

  • Authors: SADTU
  • Date: 1997
  • Subjects: SADTU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/162052 , vital:40752
  • Description: On 15 December 1997 the WCED tabled a proposal in the ELRC. This would effectively terminate the contracts of 3333 temporary educators who were filling vacant substantive posts that were created after 1 July 1996 as a result of the rationalisation process. Not only will temporary educators be dismissed, but the posts that they occupy will be frozen. This means that the teachers who remain behind at schools will have increased workloads and will have to manage bigger class sizes
  • Full Text:
  • Date Issued: 1997

Workers News - 15 000 comrades out on strike against privatisation

- SAMWU

  • Authors: SAMWU
  • Date: Sep 1997
  • Subjects: SAMWU
  • Language: English, Afrikaans
  • Type: text
  • Identifier: http://hdl.handle.net/10962/113336 , vital:33749
  • Description: The servicing of the members is a very important instrument that has to be sharpened every day if need be. In essence it is absolutely necessary to service the members, for the capacity building on policy of worker control of the organisation; building confidence, defending, developing and advancing the programmes of the organisation. We need to also build organisational skills based not on reckless or appetite militancy, but on radical concrete co-ordinated militancy. The correct flow of information is the key on empowering of the members, so that they can be able to contribute in solving the problems and take an appropriate decisions on organisational issues.
  • Full Text:
  • Date Issued: Sep 1997

Workers News - Special tenth anniversary edition

- SAMWU

  • Authors: SAMWU
  • Date: Nov 1997
  • Subjects: SAMWU
  • Language: English, Zulu, Sotho and Afrikaans
  • Type: text
  • Identifier: http://hdl.handle.net/10962/113358 , vital:33752
  • Description: It brought change in Local Government. Although this strike was a success for the organisation, we suffered losses. Many workers were dismissed and many workers suffered injuries at the hands of the security forces. This strike forced the employers to take us seriously. Another strike took place in 1995. Here again we had casualties. Workers were shot and beaten by police in places like Pietersburg, Kuruman, Bethlehem. We have workers in Groblersdal who were dismissed during that strike who have not been re-instated to this day. We have tried our best, and will continue to try. A funny incident during my term was when Cdes Tom Ngobeni, Mike Mthembu, Themba Khumalo and I called a march in Pretoria. The police station commander asked us how many workers would be marching, and Cde Tom replied "40 thousand!" When it came to the day of the march, the army lined a long street. The soldiers were heavily armed and barricaded both sides of the street. But when the march started, we were only 150! So the soldiers were far more than the marchers! The police said that they were going to sue SAMWU, but they ended up doing nothing. Now every time we want to march in Pretoria, this station commander still remembers this incident. As President of SAMWU, I feel great about the members. SAMWU members like their organisation. Wherever you go they are proud about their trade union. Even in areas where service to members is weak, those members are still proud of their union. The Union came in as a saviour to many workers, taking into account the conditions we used to work under. I always believe that if you are elected by people they should not be afraid to talk to you. I don't like it when a President is above the workers, and the workers are not permitted to say anything about their President. You have to be open to criticism, and that is the only way you can be built by others. I enjoy being a trade unionist first and foremost, but it is not an easy job to be a President. You miss your family because you never spend time with your family. My children have grown but they have never spent much time with me, except at night when I arrive home late. I think SAMWU will grow more and more. We have grown since our launch by over 100 thousand members. One of the reasons for this huge growth is that we always have a target at every Congress. During this period we didn't have a target, and that is why we did not grow so much. We need now to say that by the next Congress we should be at least 150-180 thousand in SAMWU, and make sure that we work hard to target that number. We also need public sector unity to make sure there is proper restructuring of Local Government and also to rid the public sector of corruption. Although corruption is not a new thing - it has been there for years but we need to come together to make sure that we instill that discipline within all workers in the public sector, even those that are not our members. We must make sure that all corruption in Local Government is rooted out, especially those workers in traffic departments. There are corrupt elements in every traffic department in this country. We need to build an image that will gain us respect from those communities that we are supposed to serve. Most of our members understand that SAMWU is opposed to privatisation. Once the state assets are in the hands of the private sector, government will be dependent on business. As SAMWU we say that we need a strong state to lead us, instead of the private sector leading. This will be one of our biggest challenges in the next few years. I have an important message to all municipal workers on our tenth anniversary. I would like to say that we need to improve our service delivery and make sure that we are closer to our communities. Communities must understand our problems and we must also understand their problems. We need to make sure that we democratise our union. Where there are weaknesses, members must make sure that those weaknesses are addressed. If we don't do things correctly, workers should correct us.
  • Full Text:
  • Date Issued: Nov 1997

Workers News - The war against privatisation 1997

- SAMWU

  • Authors: SAMWU
  • Date: June 1997
  • Subjects: SAMWU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/113667 , vital:33818
  • Description: SAMWU continues to fight against the privatisation of more and more services. Even’ region is facing different struggles, but let’s not forget that we are all fighting against one thing: the notion that services should be provided for profit and not to meet needs. Let’s learn about each other’s struggles so that we can prepare for united mass action! Local Authorities here are proposing to privatise the security departments of Duiwelskloof and Potgiet- ersrus TLC. In Naboom- spruit, it has been proposed that meter reading services be contracted out to private companies. Council has also spoken of putting out tenders for the maintenance of the Tzaneen cemetry. So comrades can see that we are fighting privatisation on many fronts! In Queenstown, council is attempting to privatise the refuse collection service. IMATU has joined SAMWU in rejecting this. At the moment we are trying to arrange a meeting with community structures in order to put our position forward to them. Umtata municipality proposed privatisation of the ambulance and fire departments, but noting union opposition, scheduled a meeting with SAMWU and IMATU to discuss this further. Our Aberdeen comrades are to be congratulated! We have heard that they have gone from door to door in their communities educating others about the dangers of privatisation!
  • Full Text:
  • Date Issued: June 1997

Workers News Nov 1997 - Special tenth anniversary edition

- SAMWU

  • Authors: SAMWU
  • Date: Nov 1997
  • Subjects: SAMWU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/137959 , vital:37577
  • Description: I started with the municipality in 1970 as a plumber with the technical section of the JCC. There were no unions then that organised Black workers - we were not allowed to belong to any union at that time. We were first given help by the Industrial Aid Society, then the FOSATU Workers Project, and then I became one of the first shopstewards in TGWU in 1980. It was difficult in the early days of TGWU - other workers would be afraid even to sit next to you in case they were victimised by the employer. In those days there were no wage negotiations - we used to get a 20c increase. The process in launching SAMWU was a very difficult one. We started the merger talks even before COSATU was launched in 1985. But when COSATU launched, that Congress took a decision that organiations in the municipal sector should merge. It was not an easy process but because we were all for unity in the end we achieved what we set out to do. My first main challenge as SAMWU President was to unite Local Government workers. In our history Local Government workers had no national union, whereas workers in other sectors had national unions. But in many ways, after SAMWU's first Congress, things became easier for municipal workers. We had established a solid base from which to challenge the employers.
  • Full Text:
  • Date Issued: Nov 1997

Xa ungena emzin' wam

- Group performance, Group Composition, Dargie, Dave

Yaka Yaka Ndemka

- Hogsback festival participants, Composer not specified, Dargie, Dave

Yaka Yaka Ndemka

- Hogsback festival participants, Souma, N, Dargie, Dave

Zinyanya zami nivumela ntoni

- Hogsback festival participants, Composer not specified, Dargie, Dave

Department of Economic Affairs and RDP

- Department of Economic Affairs

  • Authors: Department of Economic Affairs
  • Date: 1997-01
  • Subjects: Reconstruction and Development Programme (South Africa) , Western Cape (South Africa) -- Economic conditions , South Africa -- Economic policy
  • Language: English
  • Type: text , book
  • Identifier: http://hdl.handle.net/10962/72490 , vital:30072
  • Description: Local Economic Development (LED) is one of the primary building blocks in terms of the economic growth and development equation for the Province. The primary challenges LED has the potential to address include the following: Job creation, the building of an enabling environment that will encourage economic engagement by a larger number of local entrepreneurs, drawing together a number of critical partners and mobilising their energies and resources towards local economic growth and development, facilitating access to finance, markets, capacity building and business support services, creating the environment which will effect economic viability of local communities and their Local Authorities, linking local product development to provincial, national and international markets. There are many other fundamental challenges. The key issue though is whether people in their communities, especially rural and peripheral environments, are benefiting in real terms regarding the quality of their lives. The LED programme will also give effect to the “Growth, Employment and Redistribution: A Macro Economic Strategy” framework that outlines the strategy for rebuilding and restructuring the South African economy. The document confirms Government’s commitment: “It is Government’s conviction that we have to mobilise all our energy in a new burst of economic activity. This will need to break current constraints and catapult the economy to higher levels of growth, development and employment needed to provide a better life for all South Africans.” (1996:2)
  • Full Text:
  • Date Issued: 1997-01
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