Are prescription drug prices high?

The U.S. pharmaceutical industry has been criticized because its products are perceived to be too expensive, yet prescription medicines remain the least expensive form of therapy. At this time, we are experiencing a dramatic increase in the risks and costs of pharmaceutical research and development (R&D). An example may be seen in the R&D history of lovastatin. The U.S. pharmaceutical industry continues to lead the world in the discovery and development of important new medicines because it assumes greater financial risk and invests more of its sales dollar in R&D than virtually any other industry. Where such a risk is posed, there must continue to be the potential for profits. Pharmaceutical companies must set responsible prices, must keep price increases down, and must help improve access to important medicines.

Enzyme specificity as a factor in regulation of fatty acid chain length in Escherichia coli.

Various acyl-acyl carrier protein intermediates in saturated and unsaturated fatty acid biosynthesis were tested as substrates for beta-ketoacyl-acyl carrier protein synthetase. With both classes of substrates the condensing enzyme in fatty biosynthesis demonstrates specificities which indicate that it might be an important factor in determining fatty acid chain length in Escherichia coli.

Phosphatidic acid phosphatase and phospholipdase A activities in plasma membranes from fusing muscle cells.

Plasma membrane from fusing embryonic muscle cells were assayed for phospholipase A activity to determine if this enzyme plays a role in cell fusion. The membranes were assayed under a variety of conditions with phosphatidylcholine as the substrate and no phospholipase A activity was found. The plasma membranes did contain a phosphatidic acid phosphatase which was optimally active in the presence of Triton X-100 and glycerol. The enzyme activity was constant from pH 5.2 to 7.0, and did not require divalent cations. Over 97% of the phosphatidic acid phosphatase activity was in the particulate fraction. The subcellular distribution of the phosphatidic acid phosphatase was the same as the distributions of the plasma membrane markers, (Na+ + k+)-ATPase and the acetylcholine receptor, which indicates that this phosphatase is located exclusively in the plasma membranes. There was no detectable difference in the phosphatidic acid phosphatase activities of plasma membranes from fusing and non-fusing cells.

Manipulation of fatty acid composition of membrane phospholipid and its effects on cell growth in mouse LM cells.

Fatty acid composition of the phospholipids of mouse LM cells grown in suspension culture in serum-free chemically defined medium was modified by supplementing the medium with various fatty acids bound to bovine serum albumin. Following supplementation with saturated fatty acids of longer than 15 carbons (100 micron) profound inhibition of cell growth occurred; this inhibitory effect was completely abolished when unsaturated fatty acids were added at the same concentration. Supplementing with unsaturated fatty acids such as linoleic acid, linolenic acid or arachidonic acid had no effect on the cell growth. Fatty acid composition of membrane phospholipids could be manipulated by addition of different fatty acids. The normal percentage of unsaturated fatty acids in LM cell membrane phospholipids (63%) was reduced to 35--41% following incorporation of saturated fatty acids longer than 15 carbon atoms and increased to 72--82% after addition of unsaturated fatty acids. A good correlation was found between the unsaturated fatty acid content of membrane phospholipids and cell growth. When incorporated saturated fatty acids reduced the percentage of unsaturated fatty acids in membrane phospholipids to less than 50%, severe inhibition of the cell growth was found. Simultaneous addition of an unsaturated fatty acid completely abolished this effect of saturated fatty acids. The results suggest that maintenance of membrane fluidity by unsaturated fatty acids in membrane phospholipids is critical to membrane integrity and cell growth.

Analysis of bacterial biotin-proteins.

The biotin-protein populations in several bacterial strains were analyzed by solubilization of [3H]biotin-labeled cells with sodium dodecylsulfate followed by electrophoresis on polyacrylamide gels containing the detergent. A variety of patterns of biotin-labeled polypeptide chains was seen, ranging from a single biotin-protein in Escherichia coli, corresponding to the biotin carboxyl carrier protein component of acetyl-CoA carboxylase, to multiple species in Enterobacter aerogenes, Pseudomonas citronellolis, Bacillus cereus, Propionibacterium shermanii, Lactobacillus plantarum, and Mycobacterium phlei, which probably represent subunits of multiple biotin-dependent enzymes present in these organisms. In the case of Pseudomonas citronellolis two major biotin-containing polypeptides with approximate molecular weights of 65 000 and 25 000 were shown to correspond to the biotin carboxyl carrier components of pyruvate carboxylase and acetyl-CoA carboxylase, respectively. Thus in the case of Pseudomonas citronellolis two different biotin-dependent enzymes in the same cell do not share common biotin carboxyl carrier subunits.

Isolation and characterization of an unsaturated fatty acid-requiring mutant of cultured mammalian cells.

An unsaturated fatty acid-requiring mutant derived from Chinese hamster ovary (CHO) cells has been isolated and characterized. This mutant grows normally when oleate or other unsaturated fatty acids are supplemented in the growth medium. Unlike the wild-type CHO cells, growth stops when medium is deprived of unsaturated fatty acid. Whole cell pulse experiments with [14C]acetate or [14C]stearate indicate that the mutant is defective in unsaturated fatty acid synthesis. Enzyme assays in vitro show that the enzymatic defect of the mutant is localized to the microsomal stearoyl-CoA desaturase.

A new class of lipids: chlorosulfolipids.

Acid hydrolysis of sulfolipids from Ochromonas danica liberates 13-chloro-docosan-1,14-diol; 11,15-dichloro-docosan-1,14-diol; and other docosan-diols with three to six chlorine atoms per molecule. In stationary cells grown on 1.47 mM Cl(-), the majority of sulfolipids are chlorinated, with the hexachloro species being the most abundant.

Regulation of mammalian fatty-acid synthetase. The roles of carbohydrate and insulin.

The regulation of fatty-acid synthetase has been studied in liver, adipose tissue, and brain of diabetic and normal rats in relation to insulin administration and glucose or fructose feeding. The data indicate that: (1) insulin is not necessary for regulation of synthetase activity in liver but may be necessary in adipose tissue; (2) synthetase of liver can be regulated by carbohydrate, which can enter the glycolytic scheme in the absence of insulin (e.g., fructose), suggesting the possibility that regulation of synthetase may depend on the concentration of certain intermediates of the glycolytic pathway or beyond; (3) fructose feeding affects the synthetase by causing an increase in the rate of synthesis of fatty-acid synthetase; and (4) unlike fatty-acid synthetase of liver and adipose tissue, the enzyme of brain is unaffected by the diabetic state or by glucose or fructose feeding.

Use of beta-parinaric acid, a novel fouorimetric probe, to determine characteristic temperatures of membranes and membrane lipids from cultured animal cells.

A naturally occurring fluorescent compound, beta-parinaric acid, was employed as a probe to measure the effects of temperature changes on plasma membrenes, microsomes, and mitochondria and on their respective lipids after isolation form LM cells grown in suspension culture. A computer-centered spectrofluorimenter simultaneously measured the absorbance, absorbance-corrected fluorescence, and relative fluorescence efficiency of beta-parinaric acid incorporated into the membranes or isolated membrane lipids. These parameters were measured as a function of temperature. The probe revealed five characteristic breaks or changes in slope with both the plasma membranes as well as their extracted lipids. These discontinuities occurred at approximately 18, 23, 31, 38, and 43 degrees. The other isolated subcellular organelles, microsomes, and mitochondria, as well as their respective isolated lipids, exhibited approximately the same characteristic temperatures (+/- 1 degree) as plasma membranes. Thus, these data negate one criterion of the theory that an asymmetric distribution of characteristic temperatures exist across the membranes of LM cells.