Monday, April 28, 2008
April 28, 2008
By Syed Akbar
Hyderabad: The National Geophysical Research Institute has come out with a unique geochemical baseline mapping system which will serve as a watchdog for polluters.
The pilot project is being implemented in the backward Medak district of Andhra Pradesh. According to NGRI scientist Dantu Sujatha, the experience gained from the regional geochemical baseline mapping in Medak district will be useful for efficient planning and promoting the methodology for developing low cost environmental baseline data in other places.
Geochemical baseline is the concentration of a given chemical parameter in a given sample of geologic material at a given point in time. This is in contrast to geochemical background, which is the natural abundance of an element in a particular material with no human interference The concept of geochemical baseline mapping gained importance during 1986 after the explosion at Chernobyl nuclear power plant. Geochemical baselines are very important in environmental legislation, which prescribes limits for heavy metals in contaminated land and other surface materials as defined by environmental authorities, she said.
"While it does not appear that we are going to neutralise the threat of heavy metal toxicity in our communities nor decrease our utilisation of the many commercial goods that they help produce, we can take steps to understand this threat and put into action policies of prevention and treatment that may help to lessen the negative impact that these agents have on human health," Sujatha told this correspondent.
The increase/decrease in trace elements in soils is an important factor in the development of urban and agricultural areas as these trace elements may adversely affect the soil, environment, agricultural production or crop quality and ultimately ground water quality.
The Medak project is funded by the Department of Science and Technology. The aim of the study is not only to provide reliable analytical data to display large patterns of geochemical signatures on the regional scale, but also to investigate the different factors influencing these patterns, notably bedrock geology, climate and human influences.
Distribution patterns reflect the geological and climatic variation, differences in topography, age of the soil, land use changes, agricultural practices and pollution. The resulting database and maps would help the policy makers to decide the future industrial areas, land use, agriculture
The entire study area (9699 km2) is divided into 10/10 km grid and from each such grid; soil sampling is carried out based on the knowledge acquired from geology, morphology, vegetation, soil and hydrology maps.
The top layer usually comprised the plough layer which is vertically homogenised by agricultural practice. It is assumed that human activity primarily influenced this soil layer. The subsoil samples are assumed to represent the pristine soil composition.
Soil samples after processing are analysed for 10 major heavy and 14 trace elements.
A detailed geochemical database and preparation of high-resolution easy-to-read maps illustrates regional patterns. The visualisation of the geochemical maps aid in the integration of geochemistry with the regional geology. These maps can indicate areas where there is the potential for trace element deficiency or toxicity, enabling expensive veterinary or medical investigations to be better targeted.
Monday, April 21, 2008
April 21, 2008
By Syed Akbar
Scientists working on animal models have developed a special process to deliver vaccine onto the skin using a patch, without needles.
When it is applied in human beings, vaccination will become quite simple and virtually painless. Vaccines like cholera vaccine can be delivered without the use of needles.
Researchers at the International Vaccine Institute in Seoul, South Korea, of which India is a member, have now successfully discovered the mechanism by which a vaccine applied onto the skin can cause an immune response in the gut, as well as in the body.
The International Vaccine Institute is an international organisation which has been working for development of vaccines for the developing world. India is also a beneficiary of the IVI research. This new method is called transcutaneous immunisation or simply TCI. It involves applying a vaccine onto the skin using a patch. In previous animal and human studies, TCI was found to induce robust immune responses in blood and in mucosal secretions.
IVI's Tae Kyung Byun told this correspondent from South Korea that the IVI team had found in an animal study that dendritic cells (cells that capture vaccines and carry them to the immune system) were induced by TCI in the lymph nodes draining the gut. They were involved in the initiation of intestinal antibody responses, which are essential to stopping bacteria and virus infections.
"Such findings provide an explanation why intestinal immune responses are induced after skin immunisation, the reason for which had remained elusive until now," said IVI's post-doctoral fellow Sun-Young Chang.
The study suggests that an efficient "cross-talk" exists between the skin and gut immune systems and appears to be mediated by specialised dendritic cells in lymph nodes draining the intestines," said Dr. Kweon Mi-na, who led the study.
The IVI's study challenges the traditional notion that ingesting vaccines is the only means for inducing immunity in the gut. The results reported by Dr Kweon's team not only supports the notion that administering a vaccine in a skin patch can do the job but also provides a clue as to why this approach works, Tae Kyung Byun observed.
Monday, April 7, 2008
April 7, 2008
By Syed Akbar
A group of Japanese doctors has been removing cancerous kidneys from patients, repairing them on the surgical table and then transplanting them in people, whose kidneys have stopped functioning. This is a medical miracle as the diseased kidneys, which otherwise find their way in hospital surgical wastes, have been saving the lives of kidney-failure patients.
And Indian doctors say this Japanese medical practice could be replicated in the country to meet the acute shortage of donor kidneys. India has one of the stringent organ transplantation Rules and cadaver transplantation is still seen as a taboo here. But doctors say it will take some time for Indian health experts to make the Japanese practice an Indian reality.
"Kidney repair is quite possible and 'repaired" kidney can be used for transplant. From oncology perspective, if a cancer kidney is to be used for transplant, the tumour should be small, less than 4 cms. If the cancer size is big, it makes it impossible for transplantation," says Dr Vijay Anand P Reddy, director of Apollo Cancer Hospital.
But there's a warning attached to the repaired kidney transplantation. The tumour may recur in the rest of the kidney.
Dr Shiro Fujita of the Department of Urology, Uwajima Tokushukai Hospital, Ehime, Japan, one of the pioneers of "kidney repair" technology, however allays the fears of the Indian doctors and patients. Says Dr Shiro, "graft survival rate of restored kidney transplantation appears to be comparable to that of deceased kidney transplant when donor age and multiple previous transplants are taken into account. As far as donors/patients and recipients understand the risks and benefits, restored kidneys will be a last resort, a novel source of renal allografts in countries where the deceased donor is scarce".
Dr Shiro and his team obtained between January 1991 and September 2006, 42 kidneys from 38 patients. The lesions were removed and repaired outside (ex vivo), then transplanted.
"One, five and 10-year patient survival rates of restored transplant patients were 92.9 per cent, 79.3 per cent and 63.8 per cent, respectively. The graft survival rates of restored kidney transplant patients were 78.6 per cent, 51.8 per cent and 42.7 per cent, respectively for these years. There were no recurrence of small renal cell carcinomas.
There was one recurrence of ureteral cancer in the transplanted kidney 15 months after operation," Dr Shiro told this correspondent.
Dr Ch Subba Rao, head of the department of urology, King George Hospital, Visakhapatnam, agrees with Dr Shiro. He says repaired kidneys are possible
in certain cases in India too. "It may prove to be helpful in a state of organ shortage, but the disadvantage is the possibility of donor disease recurrence. It is going to bring down the cost of kidney transplantation."
"Because of the grave shortage of deceased kidney allografts in Japan, we have embarked on a new source of organs; restored kidneys from living patients," Dr Shiro said.
Senior urologists like Dr V Raja Gopal, however, feel that the Japanese technology cannot be replicated in India. "It is very difficult to replicate the method in a country like India. It is very risky and is associated with a lot of complications in the kidney transplant recipient.
It will be much more expensive with high risks involved. This kind of work reported from Japan has not been reproduced elsewhere in the world. In a country like India, it is not going to be answer to organ shortage," he argues.
The Japanese technology is not cost effective, points out nephrologist Dr T Ravi Raju. "Since kidney repair and transplantation are done together. Both have advantages and disadvantages. It is not cost effective". The team led by Dr Shiro has opened a sort of debate among Indian doctors on the need to introduce such a system in India where the waiting list for kidney donation is quite high.
"Urologists encounter not only patients in need of renal transplantation, but also patients who need nephrectomies. This is because we came up with the idea of using kidneys destined to be discarded to those in need of renal transplantation. Instead of autotransplantion of kidneys with aneurysms or small renal cell carcinomas after back table repair, we transplanted the kidneys into third party recipients as an innovative practice," Dr Shiro said.