摘要:

In order to test the ability of aged animals to compensate a cerebrovascular insufficiency, common carotid ligation was performed on young (12 months) and aged (30 months) rats. By using gold microelectrodes, the pO2 distribution in the cerebral cortex was registered for 1 h following the occlusion of the carotid arteries. It could be shown that, while the young group was able to compensate the reduction in arterial blood supply, the cortical pO2 distribution in the group of aged rats shifted towards a hypoxic profile. These results provide further evidence of the limited adaptability to functional demands with increasing age.

ISSN:0304-324X    

DOI:10.1159/000212266

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

There are ‘factors’ in both the cytoplasm and the nucleus which are capable of a limited digestion of the DNA in chromatin. These factors show a pH optimum closer to that of DNase I than DNase II and do not promote the activities of either of these purified enzymes. These factors show considerable tissue specificity, for example, liver extracts are less able to degrade kidney chromatin than the homologous chromatin (40% difference) and slight age specificity since ‘age-matched’ samples gave consistently higher (10%) extents of degradation. There is no evidence, however, with increasing age in mice, that the accessibility of DNA in chromatin to digestion by deoxyribonucleases is

ISSN:0304-324X    

DOI:10.1159/000212267

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The spectrum of aldimine cross-link bonds of skin collagen is dependent on the localization of the examined material. In correlation to this, there is no synchronous behaviour of cross-linkage in the aging process. The age-dependent decrease of HLNL and the increase of DHLNL in the collagen of tail tendon is only unsubstantially found in the skin of neck. It is supposed that environmental conditions or bodily activity in an area might effect the cross-link bonds of collagen.

ISSN:0304-324X    

DOI:10.1159/000212268

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The collagenous/noncollagenous protein ratio in the skeletal muscle of the male garden lizard increased with advancing age, suggesting increased tensile strength of aged muscle. The solubility of collagen and the solube/insoluble collagen ratio showed a decline during ageing confirming the development of cross-linkages in the muscle collagen of ageing lizards. It is suggested that these changes are likely to disturb the efficiency of ageing muscle.

ISSN:0304-324X    

DOI:10.1159/000212269

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

In the livers from young (3–6 month) and old (30 month) C57/BL mice and BN/Bi rats light microscope histochemistry has shown that enzyme activity is not always distributed evenly throughout the lobule. The mitochondrial enzyme succinic dehydro-genase, the plasma membrane enzyme 5’-nucleotidase and the endoplasmic reticulum enzyme glucose-6-phosphatase showed heavier reaction product in the periportal regions of the lobule compared with the centrilobular regions. Alkaline phosphatase showed an altered distribution pattern with age: in young livers this was uniform throughout the lobule while in old livers there was enhanced periportal activity. Electron microscope cytochemistry showed that this was due to increased numbers of bile canaliculi in this region containing reaction product and to the additional presence of reaction product associated with the microvilli lining the space of Di

ISSN:0304-324X    

DOI:10.1159/000212270

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

In the previous contribution to this debate, the age-associated disulfide bonding between chromatin proteins was suggested as the primary event leading to cellular aging. Evidence is now presented that S-S bond formation in chromatin may be a programmed event. The possible role of SH oxidating random events in the accumulation of S-S bonds in chromatin with age are also pointed out. Finally, the possible slowing down of the aging process with the sulfhydryl protecting-disulfide reducing agents is discussed together with some supporting experimental results.

ISSN:0304-324X    

DOI:10.1159/000212271

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Thermodynamic racemization may be a cause of aging. Racemases might accelerate the aging process. If enzymatic racemization does accelerate aging, then the use of chemical or immunological inhibitors of racemases might retard aging.

ISSN:0304-324X    

DOI:10.1159/000212272

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Lymphocyte chromosomes were studied in 10 female patients with Alzheimer’s disease, including 5 cases with positive heredity for organic dementia. The chromosomes were analyzed by means of the Giemsa banding technique. All patients had a normal karyotype with a completely normal banding pattern in all metaphases analyzed. It may be concluded that chromosomal changes demonstrable with methods available today are not involved in the causation of Alzheimer’s disease, whether sporadic or with positive heredity for organic dementia starting in the presenile or senile per

ISSN:0304-324X    

DOI:10.1159/000212273

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

A case of premature ageing (progeria) in a 3-year-old Indian child is described. The conjugations of paracetamol with glucuronic acid and sulphate, of benzoic acid with glycine and of phenylacetic acid with glutamine have been investigated in this child, in view of suggestions that these reactions are impaired in old age. The results suggest that the glucuronic acid conjugation pathway may be quantitatively less important in the progeric child than in normal children and adults.

ISSN:0304-324X    

DOI:10.1159/000212274

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The bactericidal capacity of blood polymorphonuclear granulocytes and the plasma levels of complement factors 3 and 4 did not differ between 15 aged patients and 15 young control subjects, nor did these important antimicrobial functions predict morbidity and mortality in the next 6 months.

ISSN:0304-324X    

DOI:10.1159/000212275

出版商:S. Karger AG    

年代:1978

数据来源: Karger