Age specific mortality trends in the U.S.A. from 1960 to 1980: divergent age-sex-color patterns

Trends in age-specific mortality (10-year age groups, 5-74) for the U.S. population were reviewed for all causes of death from 1960 to 1980. The age-specific mortality rate generally declined. However, the following age-sex-color groups showed divergent mortality trends compared to those of other groups: (1) The death rates for white male teenagers and young adults (ages 15-24 and 25-34) increased during 1960s and stayed at the same level during 1970s. The ratio of male to female deaths for white teenagers and young adults (15-24 and 25-34) increased over both decades, although the mortality rate for white women age 15-24 increased during the 1960s. (2) Non-white men age 15-24 and 25-34 experienced biphasic mortality trends, with a rise peaking in 1971 and then a fall. (3) The mortality ratios, non-white to white men, age 25-34 and 35-44, were far higher then those of other age groups. (4) The mortality ratios, non-white males to females, increased steadily for all age groups, and those of age groups 15-24 and 25-34 turned up sharply. Selected causes of death (1960-1977) were reviewed to uncover reasons for the unfavorable mortality trends among males. The following causes contributed to rising mortality among males: (a) accidents, suicide, and homicide for white and non-white teenagers and young adults, age 15-24, 25-34 and 35-44; (b) suicide and homicide for non-white men age 45-54; (c) cirrhosis of the liver for white men age 35-44 and for non-white 25-34, 35-44 and 45-54; (d) malignant neoplasms for white men age 35-44 and for non-white age 45-54.

Transport of glycine, serine, and proline into spinach leaf mitochondria

The transport of radioactive glycine, serine, and proline into the matrix of spinach leaf mitochondria was studied using the silicone oil centrifugation technique. The uptake of all three amino acids showed a biphasic characteristic. At concentrations higher than 0.5 mM, an apparent diffusion process dominated. The uptake was not saturable at increasing amino acid concentrations, and there was no accumulation of amino acid in the matrix (i.e., concentration was similar to that in the medium). At concentrations lower than 0.5 mM, in addition to the diffusion process, an active uptake system that accumulated amino acid in the matrix became apparent. This system was partially inhibited by rotenone, antimycin A, and carbonylcyanide-m-chlorophenyl hydrazone. Also, uptake of glycine and serine was mutually inhibitory. These two amino acids exhibited comparatively less inhibitory effect on proline uptake, and proline also did not inhibit glycine or serine uptake. The results suggest that the active uptake system consists of at least two components with different degrees of amino acid specificity. The diffusion process dominates at amino acid concentrations of 0.5 mM or higher, whereas the active uptake system becomes more prominent as the amino acid concentration decreases.

Influence of culturing on the survival of major histocompatibility complex-compatible and -incompatible thyroid grafts in rats

Culturing Fischer thyroid fragments promotes their survival in major histocompatibility complex (MHC) -incompatible ACI rats but not in MHC- compatible Lewis animals.

Isolation of spinach leaf peroxisomes in 0.25 molar sucrose solution by percoll density gradient centrifugation

A procedure for isolating spinach (Spinacia oleracea L.) leaf peroxisomes in 0.25 molar sucrose solution by Percoll density gradient centrifugation followed by removal of the Percoll by washing and centrifugation was established. The preparation contains more than 90% peroxisomes as intact organelles with no detectable chlorophyll or cytochrome oxidase contamination. The peroxisomes are stable at 0 to 4 degrees C or 25 degrees C for at least 2 hours.

Betaine accumulation and betaine-aldehyde dehydrogenase in spinach leaves

Spinach leaf discs accumulated betaine when exposed to a mannitol solution of -20 bars. The accumulation was 12 micromoles per gram original fresh weight in a 24-hour period.Betaine-aldehyde dehydrogenase (EC 1.2.1.8) was assayed in various subcellular fractions prepared from spinach leaves, and it was found only in the soluble fraction. This cytosolic enzyme was purified 175-fold, and its properties were studied. The enzyme was relatively specific for betaine aldehyde as the substrate with an apparent K(m) value of 2.08 x 10(-4) molar. It also exerted activity on other aldehyde analogs tested, but with lower V(max) and higher K(m) values. The enzyme was relatively specific for nicotinamide adenine dinucleotide as the coenzyme, having an apparent K(m) value of 9.46 x 10(-6) molar; lower activities were observed when nicotinamide adenine dinucleotide phosphate or 3-acetyl pyridine adenine dinucleotide were tested as electron acceptors. The activity was enhanced by dithiothreitol and inhibited by p-chloromercuribenzoate, and the inhibition by p-chloromercuribenzoate was partially reversed by the subsequent addition of dithiothreitol. The activity was inhibited by high concentrations of NaCl and, to a lesser extent, proline. The equilibrium of the enzymic reaction was strongly in favor of betaine formation.The in vitro activity of the enzyme under optimal assay conditions was high enough to account for the amount of betaine accumulated under water stress conditions. The enzyme activity was the same in unstressed leaves and in leaves that had been water stressed for 24 hours.

Identification of subunits of bovine heart cytochrome oxidase

Purified lipid-depleted cytochrome oxidase, at purity of 12--14 nmol heme a per mg protein, has been shown to contain seven non-identical subunits in the ratio of unity. Their molucular weights on polyacrylamide gel are, in thousands, 40, 21, 14.8, 13.5, 11.6, 9.5, and 7.6 from gel electrophoresis after dissociation in sodium dodecyl sulfate and beta-mercaptoethanol. The molar ratio is determined by the amino acid composition of each subunit obtained from direct hydrolysis of the stained polyacrylamide gel slices. The amino acid composition of the isolated subunits I and II determined by regular hydrolysis method is found practically the same as that from direct hydrolysis of gel slices. The heme-associated polypeptides are identified with subunits of molecular weights of 40.10(3) and 11.6.10(3). One of the two coppers associated with the polypeptide of molecular weight of 21 000. The second copper may be associated with heme in the subunit of 40.10(3). Evidence of the existence of interpolypeptide disulfide linkages is presented.

Subunit structure of the reconstitutively active cytochrome b-c1 complex. Determination of amino acids and molar distribution of subunit fractions from gel electrophoresis

A quantitative method has been developed to analyze the amino acid composition of protein subunits directly from the Coomassie Blue-stained band of polyacrylamide gel columns after electrophoresis. It is an improved method originally reported by Houston (Houston, L. L. (1971) Anal. Biochem. 44, 81--88). The results obtained can be thus used for the calculation of the molar ratios of subunit components of protein. The manipulation of the method and computation of the results are illustrated by a very complicated lipoprotein complex. The subunit molar ratios of the reconstitutively active cytochrome b-c1 complex were determined to be 2, 2, 2, 3, 2, 2, and 5 among the seven bands of the corresponding molecular weights of 53 000, 50 000, 37 000, 30 000, 28 000, 17 000, and 15 000, from gel electrophoretic columns. The amino acid composition of each subunit fraction determined directly from hydrolysis of gel was comparable with that obtained by actual isolation of each subunit.

Lymphocyte subpopulations: analysis of T-cell rosette characters

The data indicated that 2 populations of thymocytes existed: immature and mature types, identifiable by their rosette characters. The immature type was capable of changing spontaneously to the mature type, but was partially suppressed in vivo by the high concentration of thymic hormone present in the intrathymic environment. The mature types of thymocytes emigrated to the peripheral organ, accounting for their high percentage of small rosettes. Alternately, cells of peripheral organs might have originated from the immature type in the thymus. Once emigrated and exposed to a lower concentration of thymic hormone, they changed into the mature pattern. The fact that lymph node rosettes were less affected by culture in vitro indicated that once cells have changed to the mature pattern they have less ground for further differentiation.

Studies on cytochrome oxidase. Interactions of the cytochrome oxidase protein with phospholipids and cytochrome c

1. By the application of the principle of the sequential fragmentation of the respiratory chain, a simple-method has been developed for the isolation of phospholipid-depleted and phospholipid-rich cytochrome oxidase preparations. 2. The phospholip-rich oxidase contains about 20% lipid, including mainly phosphatidylethanolamine, phosphatidylcholine, and cardiolipin. Its enzymic activity is not stimulated by an external lipid such as asolectin. 3. The phospholipid-depleted oxidase contains less than 0.1% lipid. It is enzymically inactive in catalyzing the oxidation of reduced cytochrome c by molecular oxygen. This activity can be fully restored by asolectin; and partially restored (approximately 75%) by purified phospholipids individually or in combination. The activity can be partially restored also by phospholipid mixtures isolated from mitochondria, from the oxidase itself, and from related preparations. Among the detergents tested only Emasol-1130 and Tween 80 show some stimulatory activity. 4. The phospholipid-depleted oxidase binds with cytochrome c evidently by "protein-protein" interactions as does the phospholipid-rich or the phospholipid-replenished oxidase to form a complex with the ratio of cytochrome c to heme a of unity. The complex prepared from phospholipid-depleted cytochrome oxidase exhibits a characteristic Soret absorption maximum at 415 nm in the difference spectrum of the carbon monoxide-reacted reduced form minus the reduced form. This 415-nm maximum is abolished by the replenishment of the complex with a phospholipid or by the dissociation of the complex in cholate or in a medium of high ionic strength. When ascorbate is used as an electron donor, the complex prepared from phospholipid-depleted cytochrome oxidase does not cause the reduction of cytochrome a3 which is in dramatic contrast to the complex from the phospholipid-rich or the phospholipid-replenished oxidase. However, dithionite reduces cytochrome a3 in all of the preparations of the cytochrome c-cytochrome oxidase complex. These facts suggest that the action of phospholipid on the electron transfer in cytochrome oxidase may be at the step between cytochromes a and a3. This conclusion is substantiated by preliminary kinetic results that the electron transfer from cytochrome a to a3 is much slower in the phospholipid-depleted than in phospholipid-rich or phospholipid-replenished oxidase. On the basis of the cytochrome c content, the enzymic activity has been found to be about 10 times higher in the system with the complex (in the presence of the replenishedhe external medium unless energy is provided, and that