摘要:

Age-related changes in drug metabolism of the liver from male Lou rats were determined by measuring changes in the production of mutagens. Activation of aflatoxin B1 (AFB1), 2-aminoanthracene (2AA) and benzo[a]pyrene (B[a]P) to mutagenic derivatives was assayed using the Ames salmonella test system. The promutagens were incubated with tissue fractions isolated from rats ranging in age from 3 weeks to 18 months. Hepatic activation of AFB1 and 2AA changes with age and is maximal from 4 to 10 months. In contrast, no significant modification with age was observed for the activation of B[a]P. It is concluded that the composition of different cytochrome P-450 fractions is modified with age thereby altering the specific ability to convert different promutagens to mutagens.

ISSN:0304-324X    

DOI:10.1159/000213523

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Effects of aging on monoamine metabolism in transient cerebral ischemia were studied using adult and aged female spontaneously hypertensive rats (SHRs). Tissue monoamine contents in discrete brain areas were quantified after 20 min of cerebral ischemia with or without 30-min recirculation. Cerebral blood flow (CBF) was determined with a hydrogen clearance method in separate experiments. Dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) contents in the striatum, nucleus accumbens and septum decreased in ischemic aged SHRs, compared with those in ischemic adult SHRs. After 30-min recirculation, DA contents were actually unchanged with inconsistently increased DOPAC levels. Ischemic CBF decreased to < 20% of the resting CBF in the striatum and cortex, which was not different between the two age groups of SHRs. These results indicate that aging is primarily responsible for more severely impaired DA metabolism during cerebral ischemia in aged SHRs.

ISSN:0304-324X    

DOI:10.1159/000213524

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Young mice were found to have serum copper concentrations ranging from a low of 0.291 to a high of 0.584 ppm. Old mice had serum copper concentrations ranging from 0.223 to 1.715 with 30.9% of the old animals having values greater than 0.6 ppm. The mitogen response of isolated lymphocytes from the spleens of aging mice was greatly reduced when these cells were taken from animals with naturally occurring serum copper levels in excess of 0.6 ng of copper/mg wet weight serum. The lymphocytes taken from young mice with higher serum copper concentrations, on the other hand, had increased response to mitogens. Addition of the copper protein, ceruloplasmin, to lymphocyte cultures in vitro reduced the mitogen response of purified splenic lymphocytes with the reduction being greater for cells from old animals. We suggest that excess serum copper and ceruloplasmin may be immunosuppressive, especially in older organisms.

ISSN:0304-324X    

DOI:10.1159/000213525

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Whether or not the gastric mucosa undergoes significant changes in normal aging subjects is still open to debate. In 51 subjects undergoing endoscopy and lacking any significant endoscopic or histologic modification we evaluated mucosal thickness, gland number, numbers of parietal, chief and mucous cells at the fundus and of mucopeptic cells at the antrum, with a morphometric method, subgrouping the patients according to their age class. Our findings demonstrate that the number of parietal cells tends to increase with age and, on the other hand, the number of mucous cells is reduced in elderly subjects (p < 0.05). When considering the parietal-to-mucous cell ratio, this is significantly increased (p = 0.0005) with age. Acid secretion being an offensive factor and mucus a fundamental component of the gastric mucosal barrier, these findings suggest an increased susceptibility of the gastric mucosa to damage in the elderly.

ISSN:0304-324X    

DOI:10.1159/000213526

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

We examined age- and diet-related alterations in RNA poly(A) tail length using high-resolution gel electrophoresis followed by Northern hybridization. The results demonstrate conclusively that there is no age-related decrease in the size of the Poly(A) tail of RNA isolated from the male Fischer 344 rat. In contrast, our results suggest that there is actually a slight age-related increase in the length of the poly(A) tail isolated from the liver and hypothalamus of these rats. Dietary restriction did not affect either poly(A) tail length or its age-related increase. These data demonstrate conclusively that oligo(dT) probes can be used to standardize RNA hybridization experiments between animals of different ages and dietary groups. In addition, these data provide further evidence that the ratio between RNA polymerase I and RNA polymerase II activity does not change with age.

ISSN:0304-324X    

DOI:10.1159/000213527

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The calcium homeostatic mechanisms were explored in 31 aged individuals some of whom suffered from dementia (11 Alzheimer’s disease, 5 other dementias, 15 cognitively normal individuals). Their mean age was 81,2 ± 9,2 years, varying from 60 to 96 years. Polymorphonuclear leukocytes (PMNs) were isolated from freshly drawn citrated blood and loaded with Fura-2. Resting intracellular free calcium values, [Ca2+]o, were recorded as well as the calcium transients produced by formyl-methionyl-leucyl-phenylalanine 10-8M:Δ[Ca2+]i. The return to prestimulation values was also recorded. Average [Ca2+]o was 64.6 ± 16.0 nM and the average Δ[Ca2+]i 77.6 ± 52.7 nM. No correlation was found with age within the range explored nor was there any difference in calcium transients between demented and nondemented patients. The most surprising finding was the inability of about 30% of all examined patients’ PMNs to return the elevated [Ca2+]i values to prestimulation values. For some patients, elevated [Ca2+]i remained at the higher value, for others [Ca2+]i continued to rise. Those who could down-regulate poststimulation values did it only very slowly. Previous results obtained with leukocytes from younger individuals (under 45 years) showed a rapid return to prestimulation values. It appears that this loss of calcium-homeostatic mechanisms in old individuals is a progressive process which involves a relatively high proportion of the investigated subjects. The rate of decrease of intracellular calcium (measured by the slope P) did not correlate with diagnosis. These results show the progressive loss of calcium-homeostatic mechanisms in PMN leukocytes of old individuals but they do not demonstrate any difference between demented and nondemented individuals as far as prestimulation intracellular free calcium values are c

ISSN:0304-324X    

DOI:10.1159/000213528

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

There have been no reported studies specifically devoted to the Guillain-Barré syndrome in elderly patients. The survey reported in this paper investigated the manifestations of the disease in older patients and compared them with those seen in younger patients. All adult patients with an established diagnosis of Guillain-Barré syndrome admitted over 9 years to a Regional Referral Centre providing services for a population of 543,213 were identified and studied. Fifteen patients were over the age of 60 years and 21 between 19 and 60 years of age. Antecedent illnesses and, in particular, gastro-intestinal symptoms were reported less frequently in older patients. Where there was an antecedent illness, this was of shorter duration in elderly subjects. Neurological symptoms related to peripheral nerve damage, such as paraesthesiae, myalgia, backage and an inability to stand, occurred with a similar frequency in both age groups. Double vision and facial weakness, however, occurred less often in older patients, and cerebellar features were not encountered in the older age group. The cerebrospinal fluid immunoglobulin abnormality was more marked in the elderly. The interval between onset and peak severity was shorter in elderly patients. The duration of hospital stay was significantly greater in the elderly, though the overall prognosis was similar in both age groups. There was only one death in each group. The incidence of the Guillain-Barré syndrome in the elderly was higher than in subjects aged 19-60 years, but this difference was not significant. Although it may present with equal severity in both old and young, it carries a similar prognosis in the old and must be as vigorously managed as in younger patien

ISSN:0304-324X    

DOI:10.1159/000213529

出版商:S. Karger AG    

年代:1993

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000213530

出版商:S. Karger AG    

年代:1993

数据来源: Karger