Accumulation Of Lipofuscin Granules Research Articles

Accumulation of lipofuscin granules in acute myocardial infarction as a model of cell aging

Electron microscopic investigation of lipofuscin granules (LG) accumulation during one month in the myocardium of young rabbits in case of experimental acute infarction was performed. Accumulation of LG in cardiocytes of the ischemia-damaged myocardium area at the prenecrotic and necrotic stages was found. Analogous LG accumulation in cardiocytes in the perinecrotic area at the stage of infarction development was also observed. The fact of LG formation in fibroblast-like cells was also established. Cardiocytes and fibroblast-like cells contain a set of ultrastructurally varying LG. LG formation in functionally different cells of the ischemia-damaged myocardium is a further evidence of the active metabolic role of this organelle suggesting a common principle in LG genesis.

Is Basal Laminar Deposit Unique for Age-Related Macular Degeneration?

The ultrastructural nature and distribution of basal laminar deposit, considered to be a precursor of age-related macular degeneration, were studied in 42 human maculae. Basal laminar deposit was found from age 19 years on, not only between the retinal pigment epithelial cells and their basement membrane but also more often on the choriocapillary side of Bruch's membrane. No direct relationship was found with other aging changes, such as calcifications in Bruch's membrane, accumulation of lipofuscin granules, or drusen in the macular area. Material similar to basal laminar deposit can be found in the trabecular system, in the cornea, and also in many other organs and tissues. On a structural and morphometrical basis, we think that basal laminar deposit is similar to fibrous long-spacing collagen and thus does not seem to be a purely ocular abnormality.

Refractory heart failure and age-related differences in adriamycin-induced myocardial changes in rats.

Clinical use of adriamycin, an effective chemotherapeutic agent, has been restricted because of a demonstrated dose-limiting cardiotoxicity. To study age-related differences in adriamycin-induced cardiotoxicity, clinical status, developed force, ultrastructure, and lipid peroxide changes in the myocardium were investigated in two age groups of rats termed younger (Cy) and older (Co). Experimental animals (Cy + A; Co + A) received a cumulative dose of 15 mg/kg of adriamycin over 2 weeks. Animals in the Co + A group showed hydroperitoneum, higher mortality, and a greater decline in weight and feed consumption. Decline in base-line developed force in papillary muscles from Cy + A and Co + A group was not significant, but responsiveness to different interventions was attenuated. Papillary muscles from the Co + A group showed a significantly lesser increase over its control (Co) group in peak developed force in response to higher Ca2+. The decline in the peak developed force due to low Ca2+ and frequency increase was also significantly less in the Co + A group. Qualitatively similar but quantitatively less or even statistically insignificant changes were seen in the younger treated (Cy + A) group compared with its controls. A greater cell damage indicated by the loss of myofibrils, swelling of the mitochondria as well as the tubular system and accumulation of lipofuscin granules was seen in the Co + A group. While there was no significant change in the malondialdehyde content in the lipofuscin granules was seen in the Co + A group.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between metabolic rate, free radicals, differentiation and aging: a unified theory.

Metabolic rate is a major factor governing the rate of aging in both homeotherms and poikilotherms and is inversely related to life span. Homeotherms exhibit stable basal metabolic rates and species-specific life spans. Conversely, in poikilotherms, both basal metabolic rate and life span vary greatly. Metabolic potential (total energy consumed/g/life span) is a species-specific characteristic in Homoetherms and poikilotherms. Length of life is dependent upon the rate at which this fixed metabolic potential is expended, that is, metabolic rate. Oxygen-free radicals produced by metabolism can cause molecular damage. Accumulation of lipofuscin granules, Schiff-base-like, fluorescent material and thiobarbituric acid-reactants, as well as increased exhalation of pentane with age are indicative of free, radical-induced molecular damage. Metabolic rate influences the rate of age-related changes. There is an overlapping compensatory balance between various components of the antioxidant defense system. The total antioxidant capacity of cells tends to decline with age. A dynamic equilibrium may exist between the rate of free radical generation and antioxidant levels. The establishment of this equilibrium is associated with differentiation. It is hypothesized that loss of the equilibrium between free radical generation and antioxidant defenses results in dysdifferentiation, aging and cancer.

Electron-microscopic observation of the nucleus basilis of Meynert in human autopsy cases.

The large neurons of the nucleus basalis of Meynert (nbM) were examined with the electron microscope in 13 autopsied human adults. The neurons were characterized by a prominent Nissl substance and accumulation of lipofuscin granules. Lamellar bodies were often observed among the Nissl substance. Many of the lipofuscin granules were large and had a characteristic pronounced mosaic pattern of pale areas within gray zones. Menbranous structures within the nucleus and periodic transverse processes in the cristae of the mitochondria were regarded as postmortem alterations. Alzheimer's neurofibrillary tangles (NFT) were observed in two cases. Intranuclear fibrillary bundles were identified in four cases. Crystalloid formation in rough endoplasmic reticulum was identified in two cases. Hirano body was observed in a case of parkinsonism with dementia. Axonal swelling was seen in three cases and interpreted as axonal dystrophy, an age-related phenomenon. A basal body, which is unusual in neurons of the central nervous system (CNS), was observed in one case. Lewy bodies were observed in a case of parkinsonism.

高令者膜か牛の電顕的観察

The problem of aging has attracted the interest of many reserchers. So has presbycusis, aging of the cochlea. However, the pathogenesis of presbycusis is not yet understood completely. The purpose of this study is to examine the cochlea of aged humans using an electron microscope to characterize presbycusis. Two cases were available. The first case was an 80-year-old male, who suffered from hypertension and died of a cervical tumor. The second case was an 88-year-old male who suffered from severe diabetes mellitus. Of the two cases, the most characteristic finding was accumulation of lipofuscin granules, which were scattered diffusely in all the component cells of the cochlear duct. In the first case, the outer hair cells in the basal turn were severely degenerated, but those of the upper turns had maintained a fairly good shape. The vascular stria of the first case was normal.In the second case, the patient who had suffered from diabetes mellitus, the main pathological changes existed in the vascular stria. At the apical turn, strial atrophy was observed. At the lower turn, protrusion of marginal cells into the scala media and intercellular edema in the intermediate cell layer were prominent. These pathological changes resembled that of the K. K. mice which are a spontaneous diabetic animal.We identified the first case as sensory presbycusis and the second case as strial presbycusis.