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Nanocells contain drugs for destroying vessels supplying blood to cancer cells and chemotherapy agents to kill the cells
Nanocells sucked by tumour vessels get trapped in the tumour bed
Nanocells used to treat melanoma and Lewis lung cancer in animals
Eighty per cent of mice treated with nanocells survived beyond 65 days compared with 30 days in the case of mice treated with the best current therapy
THE BATTLE against cancer has entered a new phase and if Ram Sasisekharan and his team’s work proves to be efficacious in humans, treating some forms of cancer is likely to become effective, safe and truly path breaking.
While they have essentially used the existing methods of treating cancer, what is truly innovative is the way they have used them for achieving the same.
Dr. Sasisekharan who is a professor in the Biological Engineering Division at Massachusetts Institute of Technology, U.S., has turned to nanotechnology to achieve promising results in animal models. The results were published in the July 28 issue of the journal Nature.
Conventional methods
While conventional chemotherapy treatment is effective in treating cancer, it has its own share of problems — inability to target just the cancer cells and the possibility of cancer cells developing drug resistance.
Cells, be they normal or cancerous, depend on blood supply for sustenance and oxygen. Cutting off blood supply could be one way to kill the cancer cells.
This is however fraught with problems as cancer cells have a propensity to create new blood vessels. The process of cutting off blood supply is called anti-angiogenesis. Combining the two methods — chemotherapy and anti-angiogenesis — can be another way to kill cancer cells. This has it own limitations though — drugs that cut off blood supply not only deprive cancer cells of oxygen but also chemotherapy drugs that can kill the cancer cells.
Two-in-one
Dr. Sasisekharan used the above combination, but in a different way — `nanocells’ (of 200 nanometres in size) in a balloon within a balloon design — to deliver chemotherapy agents and drugs for destroying the blood supply to the cancer cells. The outer balloon has the anti-angiogenesis agent and the inner balloon has chemotherapy drugs.
“We tried the other combination but it will not work out,” Dr. Sasisekharan explained. “First you need a vascular shut down (blood supply cut off) and then release the chemotherapy drug.
“This will not only increase the therapeutic index but also decrease the toxicity. And this will happen only if the outer balloon is filled with an anti-angiogenesis drug.”
The ability of the `nanocells’ to wreak complete destruction of cancerous cells is aided by the cancerous cells themselves. “Tumour vessels suck things into their environment and the nanocells get trapped in the tumour bed due to their large size,” he elucidated.
The size of the nanocell plays a crucial role. While the 200 nanometre size of the nanocell prevents it from coming out of the blood vessel into organs, at the site of tumour it is a different story.
Leaky vessels
“Here the blood vessels are leaky and have pores as large as 400-600 nanometres,” he noted. “So the nanocells can pass through the vessels into the tumour where they are retained.”
In other words Dr. Sasisekharan and his team used the difference in pathology of blood vessels in the tumour and the normal organs to selectively deliver the drugs.
Once inside the tumour, the nanocell’s outer balloon disintegrates and the anti-angiogenesis drug brings about the blood vessel collapse, shrinkage and shut down.
The chemotherapy drugs in the inner balloon are then released slowly as prolonged exposure of the tumour to chemotherapy has greater efficacy in killing cancer cells.
“It may not be optimal to release the anti-angiogenesis and chemotherapy drugs simultaneously as the chemotherapeutic drugs may leak out before the blood vessels inside the tumour are cut,” he elucidated.
“If both drugs are released simultaneously, it becomes a simple combination therapy and though such a combination did show some efficacy (in our study), the nanocell was far superior to such a combination.”
Selection of drugs
The team had worked on animal models to treat melanoma and Lewis lung cancer. “There is no universal chemotherapeutic agent — they are dependent on the cancer,” he observed. “We need to find the right combination of drugs that will work for a given tumour.”
Eighty per cent of mice treated with nanocells survived beyond 65 days compared with 30 days in the case of mice treated with the best current therapy. “The 65-day period wasn’t a benchmark,” he noted. “When we started this study, we did not expect the animals to survive this long.”
This entry was posted on August 9, 2005 at August 9, 2005 and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed.
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Job Interview Tips
An interview gives you the opportunity to showcase your qualifications to an employer, so it pays to be well prepared. The following information provides some helpful hints.
Preparation:
Learn about the organization.
Have a specific job or jobs in mind.
Review your qualifications for the job.
Be ready to briefly describe your experience, showing how it relates it the job.
Be ready to answer broad questions, such as “Why should I hire you?” “Why do you want this job?” “What are your strengths and weaknesses?”
Practice an interview with a friend or relative. More....
Evaluating a Job Offer
Once you receive a job offer, you must decide if you want the job. Fortunately, most organizations will give you a few days to accept or reject an offer.
There are many issues to consider when assessing a job offer. Will the organization be a good place to work? Will the job be interesting? Are there opportunities for advancement? Is the salary fair? Does the employer offer good benefits? Now is the time to ask the potential employer about these issues—and to do some checking on your own.
The organization. Background information on an organization can help you to decide whether it is a good place for you to work. Factors to consider include the organization’s business or activity, financial condition, age, size, and location.
You generally can get background information on an organization, particularly a large organization, on its Internet site or by telephoning its public relations office. A public company’s annual report to the stockholders tells about its corporate philosophy, history, products or services, goals, and financial status. Most government agencies can furnish reports that describe their programs and missions. Press releases, company newsletters or magazines, and recruitment brochures also can be useful. Ask the organization for any other items that might interest a prospective employee. If possible, speak to current or former employees of the organization.
Background information on the organization may be available at your public or school library. If you cannot get an annual report, check the library for reference directories that may provide basic facts about the company, such as earnings, products and services, and number of employees. Some directories widely available in libraries either in print or as online databases include:
Dun & Bradstreet’s Million Dollar Directory
Standard and Poor’s Register of Corporations
Mergent’s Industrial Review (formerly Moody’s Industrial Manual)
Thomas Register of American Manufacturers
Ward’s Business Directory
Stories about an organization in magazines and newspapers can tell a great deal about its successes, failures, and plans for the future. You can identify articles on a company by looking under its name in periodical or computerized indexes in libraries, or by using one of the Internet’s search engines. However, it probably will not be useful to look back more than 2 or 3 years.
The library also may have government publications that present projections of growth for the industry in which the organization is classified. Long-term projections of employment and output for detailed industries, covering the entire U.S. economy, are developed by the Bureau of Labor Statistics and revised every 2 years. Trade magazines also may include articles on the trends for specific industries.
Career centers at colleges and universities often have information on employers that is not available in libraries. Ask a career center representative how to find out about a particular organization.
During your research consider the following questions:
Does the organization’s business or activity match your own interests and beliefs?
It is easier to apply yourself to the work if you are enthusiastic about what the organization does.
How will the size of the organization affect you?
Large firms generally offer a greater variety of training programs and career paths, more managerial levels for advancement, and better employee benefits than do small firms. Large employers also may have more advanced technologies. However, many jobs in large firms tend to be highly specialized.
Jobs in small firms may offer broader authority and responsibility, a closer working relationship with top management, and a chance to clearly see your contribution to the success of the organization.
Should you work for a relatively new organization or one that is well established?
New businesses have a high failure rate, but for many people, the excitement of helping to create a company and the potential for sharing in its success more than offset the risk of job loss. However, it may be just as exciting and rewarding to work for a young firm that already has a foothold on success.
The job. Even if everything else about the job is attractive, you will be unhappy if you dislike the day-to-day work. Determining in advance whether you will like the work may be difficult. However, the more you find out about the job before accepting or rejecting the offer, the more likely you are to make the right choice. Consider the following questions:
Where is the job located?
If the job is in another section of the country, you need to consider the cost of living, the availability of housing and transportation, and the quality of educational and recreational facilities in that section of the country. Even if the job location is in your area, you should consider the time and expense of commuting.
Does the work match your interests and make good use of your skills?
The duties and responsibilities of the job should be explained in enough detail to answer this question.
How important is the job to the company or organization?
An explanation of where you fit in the organization and how you are supposed to contribute to its overall goals should give you an idea of the job’s importance.
What will the hours be?
Most jobs involve regular hours—for example, 40 hours a week, during the day, Monday through Friday. Other jobs require night, weekend, or holiday work. In addition, some jobs routinely require overtime to meet deadlines or sales or production goals, or to better serve customers. Consider the effect that the work hours will have on your personal life.
How long do most people who enter this job stay with the company?
High turnover can mean dissatisfaction with the nature of the work or something else about the job.
Opportunities offered by employers. A good job offers you opportunities to learn new skills, increase your earnings, and rise to positions of greater authority, responsibility, and prestige. A lack of opportunities can dampen interest in the work and result in frustration and boredom.
The company should have a training plan for you. What valuable new skills does the company plan to teach you?
The employer should give you some idea of promotion possibilities within the organization. What is the next step on the career ladder? If you have to wait for a job to become vacant before you can be promoted, how long does this usually take? When opportunities for advancement do arise, will you compete with applicants from outside the company? Can you apply for jobs for which you qualify elsewhere within the organization, or is mobility within the firm limited?
Salaries and benefits. When an employer makes a job offer, information about earnings and benefits are usually included. You will want to research to determine if the offer is fair. If you choose to negotiate for higher pay and better benefits, objective research will help you strengthen your case.
You may have to go to several sources for information. One of the best places to start is the information from the Bureau of Labor Statistics.
You should also look for additional information, specifically tailored to your job offer and circumstances. Try to find family, friends, or acquaintances who recently were hired in similar jobs. Ask your teachers and the staff in placement offices about starting pay for graduates with your qualifications. Help-wanted ads in newspapers sometimes give salary ranges for similar positions. Check the library or your school’s career center for salary surveys such as those conducted by the National Association of Colleges and Employers or various professional associations.
If you are considering the salary and benefits for a job in another geographic area, make allowances for differences in the cost of living, which may be significantly higher in a large metropolitan area than in a smaller city, town, or rural area.
You also should learn the organization’s policy regarding overtime. Depending on the job, you may or may not be exempt from laws requiring the employer to compensate you for overtime. Find out how many hours you will be expected to work each week and whether you receive overtime pay or compensatory time off for working more than the specified number of hours in a week.
Also take into account that the starting salary is just that—the start. Your salary should be reviewed on a regular basis; many organizations do it every year. How much can you expect to earn after 1, 2, or 3 or more years? An employer cannot be specific about the amount of pay if it includes commissions and bonuses.
Benefits also can add a lot to your base pay, but they vary widely. Find out exactly what the benefit package includes and how much of the cost you must bear.
