摘要:

Electrolytes and/or amino acids were determined in leg skeletal muscle biopsies from elderly (age range 57–75 years) and young (age range 20–35 years) apparently healthy women. When compared to the young group, the elderly one was characterized by increased levels of muscular Na+ and Cl––, while the calculated intracellular concentration of Na+ was reduced. The pattern and levels of free amino acids showed only minor differences between elderly and young women. Intracellular Mg2+ and K+ showed a significant correlation with muscle levels of simultaneously determined energy-rich phosphagen compounds that was published pre

ISSN:0304-324X    

DOI:10.1159/000213088

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Thermal denaturation and electrophoretic mobility of liver and small intestinal mucosa fractionated chromatin and the DNA of chromatin fractions have been studied in young and old rats. During aging, the thermostability of chromatin increased, electrophoretic mobility of mono-, di-, and trinucleosomal fragments decreased at the expense of increased repeated length of nucleosomal DNA.

ISSN:0304-324X    

DOI:10.1159/000213089

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Maximal electrically evoked and voluntary contractions of the triceps surae were repeatedly measured over several weeks in 13 elderly men, mean age 69.6 ± 1.3 years. All subjects were found to be tolerant of supramaximal single twitch stimuli from the first occasion of measurement onwards and were habituated to supramaximal tetanic stimulation at frequencies of 10 and 20 Hz after three occasions of measurement. There was a significant increase in maximal voluntary contraction between the first and second occasions of measurement, but thereafter it remained unchanged. The coefficient of variation for maximal twitch and tetanic tensions and MVC were 12.5, 9.0 and 8.3%, respectively. Comparison with previously reported data showed that elderly muscle had an increased time-to-peak twitch tension development (148 ± 15 ms) compared with young subjects (113 ± 11 ms). The respective half relaxation times were 99 ± 13 and 78 ± 4 ms. Maximal tetanic tensions at frequencies of 10 and 20 Hz were significantly lower in the elderly men, 520 ± 168 and 716 ± 193 N respectively compared with 742 ± 133 and 1,162 ± 199 N respectively in the young subjects. A 2-min test involving repeated tetanisation of the triceps surae showed that though the absolute loss of tension was the same the relative loss was greater in the older than the younger men. It is concluded that muscle function in the elderly can be reliably assessed. The results suggest that the triceps surae of the elderly are weaker, more slowly contracting and show a greater relative force loss, when subjected to a standard ‘fatigue’ test procedure, than young t

ISSN:0304-324X    

DOI:10.1159/000213090

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The maximal electrically evoked and voluntary contractions of the triceps surae were measured, before and after 30 min of continuous uphill walking, in 8 elderly men aged 67–71 years. The exercise was performed on a motor-driven treadmill and corresponded to 66–74% of their predicted maximal aerobic power output. During the control period, before exercise, twitch tension (Pt), time-to-peak tension (TPT) and half relaxation time (½RT) of the maximal twitch response were 102 ± 29 N, 156 ± 15 ms and 98 ± 11 ms; the tetanic responses at frequencies of 10 Hz (Po10) and 20 Hz (Po20) and the maximal voluntary contraction (MVC) averaged 600 ± 103, 766 ± 106 and 1,225 ± 185 N, respectively. The fatigue index in response to a 2-min test involving repeated tetanisation of the triceps surae was 0.40 ± 0.14. None of these variables (except TPT which was decreased to 145 ± 11 ms, p < 0.001) was significantly changed following exercise. It was concluded that exercise of relatively high intensity and duration in healthy elderly men does not impair the force-generating capacity of the lower leg muscles nor increase their

ISSN:0304-324X    

DOI:10.1159/000213091

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Old Long-Evans male rats (24–33 months of age) do show postcastration rise in serum LH but do not have postcastration LH rise in the pituitary both as expressed in content and concentration. The serum LH levels of intact and castrated rats of old age show a tendency of decrease, though not to the level of statistical significance. The pituitary FSH content and concentration of intact old rats are not different from those of young adults (3.5–5 months of age), whereas serum FSH level of intact old male rats is significantly higher than that of intact young adults. There is a postcastration rise in the pituitary FSH content as well as concentration and serum FSH level in both age-groups. The half-lives of endogenous and exogenous LH and FSH are not different between old male rats (24- to 31-month-old) and young adults (3- to 5-month-old). Blood testosterone levels begin to decline between the age of 12 and 18 months and remained low from 18 months of age on. These results indicate: (1) deficiencies in the LH regulatory mechanism in response to removal of gonadal steroids are easier to manifest than those of FSH control mechanism in old age in male rats; (2) the ability of clearing circulating LH and FSH of old male rats is not different from that of young adult males, if their molecular sizes are similar, and (3) high serum FSH level of old male rats is not due to prolonged half-life in the circulat

ISSN:0304-324X    

DOI:10.1159/000213092

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Help for a secondary response to a determinant can be dependent on previous exposure to other determinants of the macromolecule; it can also be independent of sensitization to such carrier determinants. A helper effect, which is independent of the hapten carrier bridge, can be seen in the indirect plaque-forming response. This Th-2 type of reactivity was observed in tissue culture with spleen cells from A/J and C57BL/6 mice, immunized with various macromolecules. The spleen cells of these mice were exposed in tissue culture to the sensitizing macromolecule and to antigens conjugated to a macromolecule which was structurally unrelated to the sensitizing macromolecule. Sensitization of the spleen cell donor with the hapten was not required for this help to be given if the hapten was 2,4-dinitrophenyl, but was required when the hapten was p-azobenzene sulfonic acid. The age, at which the Th-2 helper effect was first seen, shows polymorphism. The effect was detected well after sexual maturity, and 50% of the final value was reached only when the animal had passed the 20th week of its life. The variation in age of detectable Th-2 capacity depended on the nature of the hapten; with 2,4-dinitrophenyl, as the hapten, A/J and C57BL/6J differed very little in the age at which the Th-2 capacity became detectable; with p-azobenzene sulfonic acid the Th-2 capacity was detectable at a much later age in A/J than in C57BL/6 mice.

ISSN:0304-324X    

DOI:10.1159/000213093

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

A carrier-independent type of helper activity for the indirect plaque-forming response was detected in the supernatant of spleen cell suspensions from primed mice. The potency of the factor increased during the adult life of the spleen cell donor. The factor(s) acted antigen nonspecifically and across the major histocompatibility complex. The ability of spleen cells to generate this activity was lost after treatment of primed cells with anti-Thy 1.2, anti-Lyt 1.2, or anti-Ly 7.2, in the presence of complement. The capacity to generate the activity depended on the presence of cells which adhered specifically to surfaces coated with the sensitizing antigen. The production of factor(s) involved cooperation of nonadherent T cells from primed old animals and adherent cells from unprimed donors; the age-dependent change in factor-production did not depend on the age of the donor of adherent cells.

ISSN:0304-324X    

DOI:10.1159/000213094

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The immunocompetence of 22 subjects aged 85–104 years (mean 90 ± 1 years) was studied and compared to 21 young subjects aged 19–37 years (mean 30 ± 1 years). The absolute lymphocyte number and the percentage of T and B lymphocytes in the peripheral blood was similar in the two groups. A marked decrease in phytohemagglutinin response of T-enriched lymphocytes from old subjects was observed. Autologous mixed lymphocyte reaction (MLR) was also profoundly reduced in old subjects. No difference between male and female subjects was observed. The responsiveness of enriched T lymphocytes to allogeneic irradiated non-T cells was only slightly impaired in the old individuals. Non-T cells from old and young subjects functioned equally well as stimulatory cells in allogeneic MLR. The data suggest that an alteration of T lymphocytes with regulatory function and of self-recognition is present in aged h

ISSN:0304-324X    

DOI:10.1159/000213095

出版商:S. Karger AG    

年代:1983

数据来源: Karger