Artificial red blood cells developed - C&EN Global Enterprise (ACS

Dec 9, 1985 - ... Publications/Website. facebook · twitter · Email Alerts ... This success brings the prospect of a human blood substitute closer to r...
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Compromise Superfund bill up for House vote Backroom wrangling has pried loose long-deadlocked Superfund hazardous waste cleanup bills from two committees and sent a tough fiveyear, $10 billion compromise bill to the House floor. Chemical and oil industry trade groups immediately began a beefed-up lobbying effort for a broad-based corporate tax to finance the Superfund program. The House Ways & Means Committee already backs such a taxing scheme. But support is increasing in the House for bypassing this value-added tax and replacing it with increased taxes on chemical and oil products. Those so-called feedstock taxes, which supported cleanup under Superfund, expired Oct. 1. The compromise bill was negotiated by leaders of the Energy & Commerce and Public Works & Transportation committees. The bill that emerged was harder on industry than the one supported by Energy chairman John D. Dingell (D.Mich.). Yet even he agreed with the joint statement by both committees that the bill sets in place "a sound, workable Superfund program/' That bill would set schedules that the Environmental Protection Agency must meet in studying and cleaning up hazardous waste sites on the National Priorities List. The agency would have to study more than 1100 sites in a five-year period and begin cleanup on 125 sites by fiscal 1987. Cleanups would have to meet all relevant environmental standards. However, waivers would be allowed for air and toxic substances rules but not water quality criteria. In addition, the bill would allow citizens the right to sue in federal courts to force private parties to clean up hazardous waste sites that "may present an imminent and substantial endangerment to health or the environment/' The bill also offers community right-to-know provisions. One would require chemical companies to report the location of facilities containing especially dangerous chemicals and the quantities of such chemicals. The provisions of the compromise

Dingell: a sound, workable program bill generally trouble chemical and oil companies but are applauded by environmental groups. The president of the American Petroleum Institute, Charles J. DiBona, says EPA would not be able to meet the bill's schedules, and citizens' suits would delay cleanups. Both he and Chemical Manufacturers Association president Robert A. Roland say that increases in taxes paid on the products or feedstocks of their industries would cost thousands of jobs and harm U.S. trade. The chemical and oil industries consider a broad-based tax on manufactured goods an equitable way of financing Superfund. However, opposition to such a tax is mounting among manufacturing and processing industries, with support from the White House. D

Artificial red blood cells developed Researchers in San Francisco have created artificial red blood cells that carry oxygen and have sustained laboratory rats whose natural blood was s i p h o n e d off. This success brings the prospect of a human blood substitute closer to reality. Such a substitute could save lives by temporarily replacing blood lost as a result of tissue injury. The artificial red cells consist of hemoglobin encapsulated in a lipid

membrane [Science, 230, 1165 (1985)]. They were prepared by emulsifying an aqueous solution of purified human hemoglobin with a nonaqueous solution of cholesterol and phospholipids. The lipids served as surfactants in the resulting emulsion. When the volatile organic solvents were removed under vacuum, lipid membranes began forming around the hemoglobin droplets. After several additional steps, the researchers isolated the artificial cells, which they dubbed neohemocytes. Suspensions of these bogus red cells were transfused into five lab rats to replace 95% of their red blood cells (erythrocytes). All the animals survived more than 18 hours, and two of them lived for months—long after their bodies had manufactured enough new erythrocytes to replace the artificial cells. Pharmaceutical chemist C. Anthony Hunt of the University of California, San Francisco, a n d his coworkers determined that the neohemocytes are cleared from circulation in rats with an apparent halflife of about six hours. In a medical emergency, that would allow enough time for an accident victim given a blood substitute to be whisked to a hospital for further care. But Hunt wants to extend the cells' half-life to at least 24 hours so that they are not removed from circulation before the body can replace them with its own red cells. The ersatz blood cells appear to be reasonably safe, although they are not ready to be tested in humans. The San Francisco researchers saw only minimal acute toxic effects in rats. "Although the rats look normal, they probably feel very tired," Hunt says. That's because the neohemocytes are less efficient than erythrocytes in conveying oxygen to the tissues and waste carbon dioxide to the lungs. The artificial cells carry less oxygen than normal blood because they contain only about half the hemoglobin of real red cells. And although the lab-made cells bind carbon dioxide, they don't process the gas as erythrocytes do because a key enzyme is missing. Hence, the artificial cells would have difficulty coping with respiratory demands caused by exercise. December 9, 1985 C&EN

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News of the Week Another limitation of the surrogate cells is that they cannot perform the many diverse functions of erythrocytes and other blood components. For example, because the cell membrane of a neohemocyte contains no protein, it carries no antigenicity. Hunt expects that the characteristics of artificial red cells will be improved. Nevertheless, neohemocytes already offer a number of potentially important advantages. For instance, they could be stored far longer than natural blood and theoretically could be given without regard to a recipient's blood type. And because the artificial cells are much smaller than real red cells, they can slip through constricted blood vessels more easily. Other laboratories around the world are busy developing blood substitutes based on chemically modified (not encapsulated) hemoglobins or o x y g e n - t r a n s p o r t i n g perfluorocarbons. D

PPG pruning chemical group through layoffs PPG Industries has been quietly restructuring its chemicals group since midyear with a series of small- to medium-sized layoffs. By the time the program is completed, several hundred employees—including a significant number of chemists and chemical engineers—will have either lost their jobs or been relocated and at least one production unit will have shut down. By year's end, the chemicals group will have laid off 127 salaried and 168 hourly employees at its Lake Charles, La., complex, a company spokesman confirms. Included in those numbers, according to unofficial sources, are four chemists and 26 chemical engineers. At Natrium, W.Va., 33 salaried personnel will lose their jobs. At La Porte, Tex., PPG is ending production of polyvinyl chloride initiators, a shutdown that will eliminate 12 more jobs. The chemicals group also is apparently dismantling its headquarters chemical engineering department. Of a staff of 44 salaried people, 12 are losing their jobs, nine are being 6

December 9, 1985 C&EN

reassigned to various PPG chemical plants, and, a spokesman says, it is likely that the remainder will be relocated as well. PPG, which has not made the restructuring public, will not disclose the overall goals or costs of the program. The spokesman says no charges have been made to earnings because of it. "This cost reduction was necessary for PPG to continue as a strong and viable force in the increasingly competitive global chemical markets," says Robert D. Duncan, group vice president for chemicals, speaking of the Lake Charles and Natrium layoffs. In a n o t h e r d e v e l o p m e n t that eventually could affect technical staffs, PPG has taken an option on property outside Pittsburgh for a contemplated new central R&D facility for chemicals. The facility, which would not be built for several years depending on various approvals, would include a 200,000-sqft industrial and specialty chemicals lab and a 16,000-sq-ft process evaluation lab. About 400 people, mostly chemists and chemical engineers, eventually would be employed at the contemplated lab. If the new facility is built, PPG's current chemical R&D labs at Barberton will be phased out gradually, the company says. D

Interleukin-2 technique promising cancer tool A technique that appears to be successful in activating certain cells of the immune system to destroy cancer cells in patients whose cancers are so far advanced that they no longer respond to conventional methods of treatment has been developed by researchers at the National Cancer Institute. Steven A. Rosenberg, chief of the surgery branch at NCI, and colleagues have reported preliminary, but extremely promising, results in 11 of 25 patients with a variety of types of cancer [N. Engl. J. Med., 313,1485 (1985)]. The technique uses interleukin-2, a naturally occurring messenger substance of the immune system. The researchers use massive doses of interleukin-2, produced by genetic

engineering techniques, to treat a type of white blood cell called a lymphocyte, which they have previously extracted from the cancer patient's blood. When stimulated with interleukin-2, certain lymphocytes develop into cells that can kill tumor cells without harming normal cells. Those lymphocytes, which the researchers call lymphokineactivated killer (LAK) cells, are then injected back into the cancer patient, along with further doses of interleukin-2 to assure that they multiply within the body. Of the 25 patients treated this way by the NCI researchers, 11 (or 44%) responded to the treatment with at least a 50% reduction in the size of their tumors. In one patient, with a skin cancer called melanoma, the cancer disappeared completely and has not recurred in 10 months of followup investigation. The other patients showing significant responses had melanoma, colorectal, kidney, and lung cancers—all cancers that are difficult to treat with c o n v e n t i o n a l t h e r a p i e s . No responses occurred in four patients with sarcomas and in one patient with cancer of the esophagus. The technique is "the most promising biological approach to cancer at the present time/' says Vincent T. DeVita Jr., director of the National Cancer Institute. "It clearly is producing a fairly dramatic effect in people with advanced cancer." Rosenberg says, "This is really the first step, but it demonstrates that it is possible to manipulate the immune system and make a variety of cancers in a variety of locations disappear." The technique has significant side effects, which require that patients undergoing this treatment be hospitalized, often in intensive care units, throughout their treatment. The most serious side effect is weight gain caused by fluid retention. Sixteen of the 25 patients gained more t h a n 10% of their starting weight; 20 developed fluid in the lungs, causing mild breathing difficulties for 18 and severe distress for two. Patients also developed chills and fever following injection of the LAK cells. All of the adverse effects stopped when interleukin-2 treatment ended. D