HKU Bulletin October 2004 (Vol. 6 No. 1)

13 12 RESEARCH T he theory that an asteroid likely killed off the dinosaurs is a well- known one. But objects f rom space have caused other catastrophic effects on Earth. Dr Jason Ali, Assistant Professor of the Department of Earth Sciences has recently helped to explain a collision that devastated northeast Thailand and left behind glassy black fragments across a vast area stretching from Madagascar to Australia and China. The fragments, called tektites, are pieces of molten rock that were thrown into the air at the time of the collision and came back to Earth with air and gas trapped in them. Dr Ali became involved in explaining the mysterious source of these objects at the invitation of a National Geographic funded team of Australian and Thai scientists, who were investigating a strange geological deposit in northeast Thailand. Huge blackened tree stumps and fossils of mammals had been uncovered at the site by builders digging for sand. This looked like the site of a collision – ‘ground zero’ – and Dr Ali was asked to date the deposit through its magnetic record. This information was then linked to the tektites. “When they took me to the sand pits I was amazed. It was just like a giant had trashed one of those massive North American Unearthly Discovery in Thailand lumberyards you sometimes see on TV. The trees were al l haphazardly stacked, burnt and cleanly snapped off five or 10 metres above their bases,” he said. “Both the force and the intensity of the fire required to do that must have been incredible.” Dr Ali dated the impact to 780,000 to 800,000 years ago – relatively recent, in geological terms. The findings have just been published in Earth and Planetary Science Letters by Dr Ali and Peter Haines, Kieren Howard and Clive Burrett of the University of Tasmania in Australia, and Sangad Bunopas of Thailand’s Department of Mines. “There is pretty convincing evidence that an impact killed the dinosaurs 65 million years ago. This thing was quite a bit smaller, but the effect of these things depends on where they land,” Dr Ali said “ . Apart from the devastation of this forest, there was no real impact on animal or plant life. It hasn’t changed evolution like the dinosaur event.” But it has provided a novel source of income for Thai farmers. They sel l tektites to curio shops, where tourists, including geologists, snap them up. T he University is playing a central role in new groundbreaking research into the treatment of spinal cord injuries. Clinical trials on new therapies, involving cell transplantation and drugs, will be carried out at six centres on the Mainland and in Hong Kong, co-ordinated by Professor So Kwok Fai of the Department of Anatomy. “For many years it was thought that if the spinal cord was damaged, it could not be repaired. But in the past few years there have been a lot of breakthrough studies of new therapies that suggest otherwise,” Professor So said. “What the China Spinal Injury Network wants to do is to apply these therapies in systematic clinical trials.” The University’s Clinical Trials Centre, headed by Professor Johan Karlberg, will co-ordinate the testing, with responsibility for everything from training and organising clinicians who deliver therapy and evaluate patients, to ensuring international standards are m “W et e . are not treating patients at the centre. What we’ve been brought in to do is to ensure the quality of the testing – that it’s going to be ethical, safe and trustworthy,” Professor Karlberg said. The testing will be carried out at hospitals in six cities – Hong Kong, Beijing, Guangzhou, Shanghai, Xian and Zhengzhou – and will involve a variety of treatments. The Hong Kong team includes Professor Keith Luk Dip Kei, Professor: Chair of Orthopaedic Surgery and Dr Wong Yat Wah from Queen Mary Hospital. Cell-based therapy will be tested, in particular stem cells and the olfactory ensheathing cells (OEC), which surround the nerve cells in the nose and which receive sensations of smell. Both stem cells and OECs have been shown to successfully promote axonal regeneration in the spinal cords of animals. “However, the future is not going to be just cel l transplantation, but combinations with other drugs that will facilitate recuperation,” Professor Young said. “The therapies studied in animals that are the most effective are combination therapies. Many therapies are ready to go to clinical trial, but there are not many places that can do it on the scale of China.” Some of these therapies involve drugs that are already used by people, such as lithium, which is used to treat mania and depression. A research team at the University, including Dr Wu Wutian, Associate Professor and Professor So recently combined lithium chloride with chondroitnase ABC (an enzyme which digests scar t issue) treatment and found i t signi f icant ly improved limb function in spinal cord injured rats. The results were published this year in the Journal of Neurotrauma , although it is not yet decided whether this treatment will be tested in the network. Seeking a Cure for Spinal Cord Injuries Several treatments, including the use of OECs, have been carried out on a few hundred patients in Beijing and shown some success, although they were not conducted with control groups, protocol and other regimented circumstances required for a proper clinical trial. The first task of the network will be to raise US$2 million (HK$15 million) to cover the cost of the initial trials. A Hong Kong Spinal Cord Injury Fund has been launched and Professor Young was confident they could raise the money to ensure testing started before the end of next year. The costs are much lower than the estimated US$800 million paid by drug companies to bring one new drug to market, because of lower costs in China and the fact the Clinical Trials Centre is a non-commercial centre. The timeline is also likely to be much shorter than the 10 years or so that are the norm in the commercial world. “China offers a unique opportunity to accelerate these therapies from the laboratory bench to the bedside. You have dedicated doctors and a strong commitment from the University of Hong Kong to co-ordinate this task. This network could enable us to assess one treatment every year,” Professor Young said. He expects to be able to treat 6,000 patients a year once the network is up and running. He also expects the results to be immediately acceptable to regulatory bodies in the United States and Europe because of the high international standards that will be applied in the trials.