[Structural changes in the hepatocytes of old rats with posthemorrhagic anemia]

Using light and electron microscopy, and morphometry, it has been demonstrated that 15 min and 2.5 h after a single blood loss (2% of the body mass) organelle disintegration and destruction are more marked and preserved in hepatocytes of old (25-month-old) rats, as compared to adult (8-month-old) animals. Regenerative processes in adult rats lead to hepatocyte structure normalization already by the 10th hour after the experiment was started, while in old rats disseminated fatty dystrophy of hepatic cells is observed even on day 7. Thus, hepatocytes of old animals are more susceptible to blood-loss-induced disturbances, with the regenerative processes in them being less marked and slower than in adult animals.

Age-related trend for osteopenia in femurs of female C57BL/6 mice

Age-related changes in femoral cortical bone were quantified in female C57BL/6 mice. Variables included in this study were cortical thickness; number of osteocytes and periosteal preosteoblasts; bone DNA, protein, calcium, and phosphorus content; and uptake of 3H-thymidine, 3H-proline, and 45CaCl2. Also, the activity of bone alkaline and acid phosphatase was measured as well as the hydroxyproline content of the tissue. Femurs of old mice 28 months old, compared to those of young mice 7 months old, showed significant decreases in cortical thickness, number of bone cells, bone mineral content, and enzyme activity. The latter were accompanied by a marked reduction in ability to incorporate radiolabeled precursors of DNA and collagen synthesis as well as of the mineralization process. Hence, aging female C57BL/6 mice reveal structural and biochemical features indicative of developing osteopenia.

The aging eye. A family physician discusses some inevitable changes and suggests methods for dealing with them

The aging eye undergoes a variety of structural and physiologic changes that can impair vision and cause functional disability. Among the changes are backward displacement of the eye into the orbit, thickening and yellowing of the lens, decrease in pupil size, increase in laxity of the lids, and accumulation of waste products in the retina. The specific diseases of the eye that occur with aging include macular degeneration, cataracts, glaucoma, diabetic retinopathy, and sudden vision loss. Preventive care both in old age and earlier in life may help forestall ocular changes and the subsequent morbidity and mortality they cause. Environmental changes to accommodate visual change can be important in accident prevention and in improved functioning and quality of life.

[The adrenal medulla and adrenergic innervation of the ventricles of the heart during the postnatal period of ontogenesis of the white rat (histofluorescent study)]

The sympathetic innervation of the cardiac ventricles and dynamics of catecholamine contents in the adrenal medulla have been investigated in inbred white rats (1-3-week-old, immature, mature and old animals). During 1-3 weeks of age, development of adrenergic innervation of the heart is observed, in 1.5-month-old rats in approaches that in mature animals. In the old rats the arrangement density and fluorescent intensity of the adrenergic terminals of the cardiac ventricles in comparison to those in the mature animals decreases considerably. Catecholamine contents in the adrenal medulla in 3-week-old rats practically reaches those specific for mature animals. In the old animals the amount of catecholamines in the adrenal medulla decreases by 20%, comparing to those in the mature animals. Thus, maturation of the mediator link of the sympatho-adrenomedullary system is performed in it later than the hormonal one, while processes of old age involution are more intensive.

Age-related changes in iliac crest trabecular microanatomic bone structure in man

Age-related changes in the microanatomic structure of human iliac crest trabecular bone have been investigated in biopsies from 90 subjects, using a new computerised method which automatically identifies and quantifies nodes, free ends and a number of topologically defined struts. In both sexes there was a significant age-related decrease in the number of nodes and of trabecular struts, corrected for section area. In females, there was also a significant age-related decrease in the node to free end ratio (P less than 0.001), and the combined node-to-node and node-to-loop strut length, expressed as a percentage of total strut length (P less than 0.001) and a significant increase in free end to free end strut length (P less than 0.001). In males, the only additional age-related change was a significant increase in the cortex to free end strut length (P less than 0.005). These results indicate that loss of trabeculae resulting in decreased interconnectedness of the normal trabecular bone structural pattern, plays an important role in age-related bone loss in females. Removal of trabeculae also occurs in males but in less prominent, implying that trabecular thinning makes a greater contribution to age-related bone loss in males.

Morphometric analysis and fine structure of the vestibular epithelium of aged C57BL/6NNia mice

The vestibular organs of young and very old C57BL/6NNia (B6) mice were compared by light and electron microscopy. Hair cell density decreased an average of 14% in the utricle, 19% in the saccule and posterior crista, 23% in the horizontal crista, and 24% in the anterior crista. Hair cell size remained the same throughout the mouse's life span as did the ratio of Type I to Type II hair cells. The most apparent sign of advanced age was dense inclusions found in sensory and supporting cells. Although small inclusions were present at five weeks, by 29 months, additional, larger forms appeared. An unusual melanin-like form was characteristic of old Type I hair cells. Synaptic morphology and synaptic bodies were well preserved even in very old B6 mice. Elongated bars were common in Type I hair cells and spheroid synaptic bodies were the most common form in Type II hair cells. Large clusters of synaptic bodies occurring in both young and old mice were seen only in Type I hair cells. Although the B6 strain suffers from genetically determined early cochlear degeneration, it does not experience early degeneration of the peripheral vestibular organs.

Cognitive and neurologic findings in demented patients with diffuse white matter lucencies on computed tomographic scan (leuko-araiosis)

A series of patients referred to the University of Western Ontario, London, Dementia Study for investigation of possible dementia underwent computed tomographic scans, psychometric testing (Extended Scale for Dementia [ESD]), and neurologic examination. Thirty-nine of the 113 patients studied (ischemic score, less than or equal to 4) were found to have leuko-araiosis, which we have defined as patchy or diffuse lucencies in the white matter. Patients with leuko-araiosis had significantly lower mean scores on the ESD, 109.7 +/- 61.2, compared with mean scores of 148.5 +/- 78.0 in those without. However, only a trend toward lower scores on the ESD was observed when age, sex, education, and infarct were taken into account in the analysis of covariance. Leuko-araiosis was found to be associated with increasing age, hypertension, abnormalities of power in the limbs, and extensor-plantar responses in this sample of patients. In patients with Alzheimer's disease (AD) alone, diagnosed clinically, 29 out of 91 demonstrated leuko-araiosis on computed tomography, but scores on the ESD in this group overall were not significantly different when those with and without leuko-araiosis were compared. In less advanced cases, however, a highly significant trend was evident for leuko-araiosis to be associated with increased dementia in AD. The results are consistent with the hypothesis that leuko-araiosis is associated with dementia in AD, and that this is either most marked or most easily identifiable before the dementia becomes very severe.

Aging and the cardiovascular system

As a result of aging, a variety of structural and biochemical changes occur in arterial walls that result in hemodynamic adaptations. With age, there is a thickening of intima and media, together with an increase in the number of smooth muscle cells, synthesis of collagen and elastin, and deposition of calcium, glycosaminoglycans, free and esterified cholesterol, and sphingolipids. These changes are similar to those observed in atherosclerosis, which is accompanied by marked increases of intimal smooth muscle cells and connective tissue constituents. The net effects of both aging and atherosclerosis are a loss of elasticity and distensibility. This results in a decrease in arterial compliance or capacitance, which in turn means that with increasing age systolic blood pressure (SBP) tends to be higher, and diastolic blood pressure (DBP) lower. As a consequence of structural changes both in myocardium and vessels, cardiac output and renal and hepatic blood flow undergo adaptive alterations in order to meet the requirements of central hemodynamics and peripheral circulation. The implications of these processes of aging demand appropriate treatment of cardiovascular disorders, in particular hypertension, which occurs in 30-50% of patients above the age of 60 years. Appropriate treatment may demand dose adjustment and careful selection of antihypertensive drugs with a minimum of side effects, which additionally are capable of diminishing preload and afterload.

Fixation effects on synaptic vesicle density in neuromuscular junctions of young and old mice

It was previously reported that in soleus neuromuscular junctions of old mice, synaptic vesicle density was decreased while transmitter release was increased (compared to results in young mice). In the present study, two hypotheses that might resolve this disparity were tested. The first was that the density of readily releasable vesicles close to the preterminal membrane, rather than those in the whole terminal, would correlate with the physiological results. This hypothesis was excluded because both vesicle density in the 200 nm region just within the presynaptic terminal membrane, and total vesicle density were similarly reduced in old soleus junctions. The second hypothesis was that more transmitter was released during fixation at old than at young neuromuscular junctions, leading to an age-related depletion of vesicles. This was tested by counting vesicles in muscles fixed after transmission block was attained in Krebs solution lacking calcium, and by direct recording of quantal release during conventional fixation. This second hypothesis was excluded: in neuromuscular junctions exposed to zero-calcium Krebs solution before fixation, the age-related reduction in vesicle density was still present, and intracellular recording revealed only a slight increase in quantal transmitter release during fixation. Therefore, as discussed, other mechanisms must be considered.

Axonal polyglucosan body in the ventral posterolateral nucleus of the human thalamus in relation to ageing

Axonal polyglucosan bodies in myelinated axons in the ventral posterolateral nucleus of the human thalamus (VPL) are described. These axonal inclusions were distributed exclusively in the dorsolateral part of the caudal VPL, and their arrangement may be associated with fibres originating from the gracile nucleus. They were not observed in patients under age of 50, and appeared to increase in number and size with advancing age. It is suggested that axonal polyglucosan bodies are an ageing phenomenon of the secondary sensory fibres.

Changes in bone marrow blood flow with aging

We investigated changes in bone marrow blood flow and histology with aging in rabbits. Bone marrow blood flow was measured by the hydrogen washout method, which was performed in the proximal tibia of Japanese white rabbits, 3-42 months of age. Bone marrow blood flow was found to decrease with age. Histological observations of the proximal tibia identified a decrease in the number of osteoblasts and hematopoietic cells, an increase of the number of empty lacunae, a reduction in bone formation rate, and a degeneration of marrow fat with aging. These results suggest that the decrease of bone marrow blood flow is related to histological changes found with aging.

Effect of aging and exercise on the kidney. Anatomical and morphological studies

The effect of short-term endurance exercise on the kidneys of C57BL/6J mice of various ages was studied. While as a function of age there was a slight increase in the ratio of kidney weight to body weight, after 6 weeks of training there was a significant hypertrophy of kidneys of old mice compared to young ones. In addition to these gross anatomical studies, light- and electron-microscopic studies were performed. Using light microscopy, semiquantitative morphological assessment of kidney damage revealed that in young animals about 66% of total glomeruli were characterized as normal. 32% of the glomeruli were singled out as slightly damaged but still functioning. These values remained basically the same for kidneys of young animals trained for 6 weeks. In old mice, on the other hand, only 37% of total glomeruli were characterized as normal morphologically, and over 60% showed various degrees of kidney sclerosis. Exercise for 6 weeks reduced the proportion of normal-appearing glomeruli to 6.25%, while the damaged glomeruli of all types increased to over 90%. Electron-microscopic pictures revealed an increased amount of mesangial damage and severe obliteration of capillary lumens in aging animals. These changes were magnified in old running mice. The results may indicate that while kidneys of young animals were not affected by 6 weeks of exercise, kidneys of old animals were adversely affected by this type of exercise regimen.

Anatomy, function and aging in the mouse liver

A brief overview is given of the embryology, gross and microscopic anatomy and sinusoidal lining cells of the mouse liver. The handling of xenobiotics is also considered. So called phase I and II reactions are of major importance. Furthermore, heterogeneity of metabolism occurs in the different zones of the hepatic acinus. Finally, some of the manifest pathological changes are discussed. Despite the occurrence of these changes there is still no clearcut evidence that liver function declines with age.

The role of the nucleus basalis of Meynert in dementia: review and reconsideration

The nucleus basalis of Meynert (nbM), a cholinergic nuclear group located in the sublenticular region, receives afferent input principally from the limbic system and projects to most of the cerebral cortex. The nucleus is atrophic in dementia of the Alzheimer type (DAT) and several other dementing disorders and attempts have been made to relate cholinergic deficits as well as intellectual impairment to nbM alterations. A cortical cholinergic deficit is routinely associated with atrophy of nbM, but there is no consistent relationship between changes in nbM and histopathologic alterations of the Alzheimer type and a variable association between nbM changes and dementia. The available information suggests that atrophy of nbM and cortical cholinergic deficits have a contributory role in several dementia syndromes but cannot account for many pathologic and behavioral aspects of these disorders.

Sequestration hypothesis of atherosclerosis

Atherosclerosis of the human aorta has been studied by morphometric, chemical, and histochemical methods. Results of these separate approaches are converging upon a theory of pathogenesis. This theory begins with the standard view of a two stage process, intimal fibroplasia followed by atheronecrosis in the most thickened and aged places. The first stage, fibroplasia, can be described in terms of a stochastic process wherein smooth muscle cells, scattered in accordance with a Poison distribution, elaborate matrix materials over time, causing the realms of the cells to expand and to aggregate. The fusion of the expanded smooth muscle cell realms seems to mark the advent of necrosis. The second stage, atheronecrosis, can be described such that the probability of a necrotic core emerging at a site in a vessel is governed by the amount and the age of interstitial matrix materials at the site. Further evidence shows that the matrix materials tend to sequester lipids in greater than proportionate amounts as the intimal bulk increases. The sequestered perifibrous lipid is histochemically different from the lipids of the necrotic core, in that only the latter can be fixed with chromic acid. These results suggest that lipids undergo a qualitative change as well as a quantitative increase at the stage of impending necrosis. This qualitative change is governed by age, which raises the possibility that necrotizing toxicity accumulates in the sequestered lipid as it ages.

Giant mitochondria in the myocardium of aging and endurance-trained mice

During the course of an ultrastructural study on the apex region of the left ventricular myocardium of experimental female C57BL/6J mice, aged between 6 and 27 months, and that had been subjected to long-term daily enforced endurance running schedules, we encountered some instances of unusual giant mitochondria. These mitochondria showed degenerative changes including the disruption, disorganization and loss of cristae and the development of a very electron-lucent matrix. In many instances, these giant mitochondria showed dense inclusions within the matrix. The giant mitochondria appear to have developed as a result of fusion between adjacent hypertrophic mitochondria followed by a sequence of progressive degenerative changes. These giant mitochondria were most common in the myocardium of mice that had followed endurance training schedules for 10 or 15 months and were not encountered in age-matched nonrunning control mice.

Nuclear magnetic resonance imaging in the aging brain

43 patients aged over 55 years with different clinical diagnoses but with the common aspect of impairment of the cognitive functions underwent a 0.5 Tesla magnetic resonance imaging (MRI) investigation in order to obtain further information about the pathological causes underlying the clinical syndromes. The occurrence of white matter signal alterations (periventricular lucency) and of multifocal ischemic areas represented the most frequent and atypical finding. Independently of the clinical focal symptomatology, these data might well represent a marker of a diffuse tissue sufferance due to a chronic mild cerebral hypoperfusion. The incidence of similar findings in 'normal' elderly subjects must be assessed before giving them a definite relevance in the evaluation of the pathological aging.

[Proliferative processes in the myocardium in different parts of the heart during the creation of experimental myocardial infarct of the left ventricle in 2- and 3-week-old rats]

As a result of 30 times repeated injections of 3H-thymidine (3HTdr) to neonate rats, beginning from days 13 or 21 post partum, ca. 20 and 10% of myonuclei in the left and right atria were labeled, respectively, while in both ventricles cumulative labeling of myocytes was nearly ten times lower. In rats of the same age with experimental infarction of the left ventricular myocardium the number of myonuclei labeled after 30-fold 3HTdr injections increased in atria up to 40-50%, in perinecrotic myofibers of the left ventricles up to 8-11%, and in myofibers of the left and right ventricle located far from the necrotic foci up to 3-4 and 2-3%, respectively. In some of rats subendocardial and/or subepicardial layers of the surviving left ventricular myocardium contained up to 15-35% of labeled myonuclei. Thus, in neonatal rats the extent of DNA synthesis reactivation in the nuclei of cardiomyocytes, the majority of which have recently completed normal ontogenetic proliferation, is, on the whole, of the same order as found in similar experiments on adult rats (Rumiantsev, Kassem, 1976; Oberpriller et al., 1984). However, still immature ventricular myocytes of neonatal rats resume mitotic cycle easier than those of adult animals which is evidenced not only by higher numbers of 3HTdr labeled myonuclei in subepicardial and subendocardial ventricular myocardia of some rats, but even more by reactivation of DNA synthesis in a limited fraction (2-3%) of the whole population of non-perinecrotic myocytes in both ventricles. Besides, reactive proliferation of cardiomyocytes in the atria of neonate rats, unlike in adults, starts on day 3 rather than on day 5 after infarction is induced. In the atria of neonatal rats polyploidization of myonuclei at later postinfarction stages is less pronounced than in adult rats which may be accounted for by formation of individual daughter nuclei during acytokinetic mitoses or, more seldom, by completion of cytotomy.

The change in aggressiveness of neoplasms with age

With aging, tumors occur more frequently. The "malignant" characteristics of tumors (ie, rapid growth and metastases), however, appear to be less prominent in the elderly. In experimental tumor models, similar observations have been recorded. The reason for this phenomenon could be that tumors (ie, malignant cells) are different in different-aged hosts. Alternatively, host features such as the fibrotic, angiogenic, or immune response may be altered by the aging process and may render the host "soil" less fertile for "malignant" tumor growth. Indeed, experimental evidence has supported the importance of each of these host features. The significance of the exploration and eventual understanding of the age-related change in tumor behavior extends beyond clinical geriatric medicine; it may, in fact, involve the very unraveling of some of the basic biology of both tumor control and the aging process itself.

Vascular risk factors and leuko-araiosis

Leuko-araiosis was found in 49 of 140 demented patients compared with 12 out of 110 control subjects. Thirty-one of 95 patients with dementia of the Alzheimer's type had leuko-araiosis. A history of stroke was four times more frequent in patients with leuko-araiosis than in those without leuko-araiosis (17.4% and 4.4%, respectively). It occurred in 25% of controls with leuko-araiosis compared with only 2% of those without leuko-araiosis. Mean systolic blood pressure was associated with leuko-araiosis. No association was found for diastolic blood pressure, myocardial infarction, angina, diabetes, or carotid bruits. On logistic regression analysis, the strong association between dementia and leuko-araiosis was mainly explained by a history of stroke. There are common factors in leuko-araiosis and stroke, but stroke alone does not account for leuko-araiosis.

[Modification of Bielschowsky's method for detecting senile plaques and intracellular neurofibrils]

The distinction of the modification of Bielschowsky's method lies in additional colouring of silver-golden sections with strong solutions of stable cresyl-violet and acetic acid, as well as in recommendations to use precise-profile cortical sections. The given modification helps to obtain preparations with definite orientation and guaranteed identification of different nerve tissue elements. The preparations obtained can be employed for quantitative analysis and for a detailed study of thin specific structures and cytologic properties of pathologically changed nerve and glial cells.

Etiologic factors of myelopathy. A radiographic evaluation of the aging changes in the cervical spine

The radiographic characteristics of the cervical spine among older individuals were investigated in 100 normal subjects and compared with those of younger subjects. The cervical spine of the older subjects displayed narrowing of intervertebral discs and osteophytoses (posterior osteophytes as well as anterior osteophytes) at the levels of C5-6 and C6-7, where the range of motion was decreased. Such degenerative changes resulted in vertebrolisthesis, especially retrolisthesis, predominantly at the levels of C3-4 and C4-5, where intervertebral disc space was well maintained and mobility was well preserved. Both static and dynamic anteroposterior canal diameter decreased with age. Throughout the aging process the dynamic canal became much narrower than the static canal, except at C2-3. Posterior osteophytes at C5-6 or C6-7 and retrolisthesis at C3-4 or C4-5 were major levels of stenosis associated with changes in the dynamic canal. Following the same evaluation system, 20 elderly patients with cervical spondylotic myelopathy were assessed. Based on the above-noted characteristics of the aging process, patients with myelopathy had smaller static and dynamic canal measurements than normal subjects. The development of cervical myelopathy, however, was not always based on critical static or dynamic canal stenosis (10% in this series) and might involve other factors.

Histochemical and proliferative changes preceding the onset of spontaneous gastric adenocarcinoma in Mastomys natalensis

The histochemical and proliferative changes preceding spontaneously developing gastric adenocarcinoma were examined in Mastomys natalensis. The stomachs of 86 inbred animals from the DWZ strain were examined between 1 and 24 months of age. Two thirds of the animals had a small solitary ulcer in the middle of the lesser curvature which was observed by the first month of age. With increasing age, more and more dysplastic glands invading the submucosa were seen around the ulcer and eventually adenocarcinoma was observed after 12 month. Histochemical alterations included increased intracellular peanut lectin and Concanavalin A binding sites in the gastric pits and the development of lectin binding sites and of acid glycoproteins in the surface epithelium. Using 3H thymidine and autoradiography increased labelling and mitotic indices with extension of the progenitor area to the mucosal surface were observed around the ulcer. The coexistence of these histochemical and histokinetic alterations may represent an early sign of malignant potential in the gastric mucosa.

Relative deficiency of serine proteinase activities in spleens of aged mice

We examined the relation of hydrolytic enzymes in spleen to the aging process in mice over a period of 30 months. When the enzymatic activities were expressed as activities per milligrams protein, those of serine proteinases and dipeptidyl peptidase IV (Gly-Pro-AP) significantly decreased with age, whereas that of L-leucine aminopeptidase (Leu-AP) increased significantly. However, when expressed as total activities, the enzymatic activities in spleen generally tended to increase with age, except in the case of serine proteinases, because of the age-related increase in spleen weight. The results were taken to indicate that the activities of serine proteinases become relatively more deficient in the spleen as age increases. The results of a multivariate study maintained this peculiarity of serine proteinases in comparison with other enzymes. The relative deficiency of serine proteinases in spleen may be somehow related to immunodeficiency in aged animals, as judged from similar findings in animal models of systemic erythematodes.

Selected pathological findings in the human cochlea

Out of a material of 45 patients with known audiograms where the inner ears had been fixed with an aldehyde within 7 h after death, 4 cases were chosen for detailed morphological examination. The general findings in the ageing human cochlea are presented as well as the findings in the 4 specific cases.

The fine structural morphology of the midgut of aged Drosophila: a morphometric analysis

The midguts of 1-day and 72 day-old fruitflies were examined morphometrically at the electron microscopic level. The major alterations noted were that the number of supranuclear mitochondria decreased by approximately 50%, while the volume of individual mitochondria doubled as a function of age. Moreover, approximately 29% of the nuclear volume of old flies, was occupied by inclusion bodies as was 19% of the supranuclear cytoplasmic volume. Additionally, the surface density of rough endoplasmic reticulum was reduced to more than half that of young flies. It is suggested that the functional capability of the parenchymal cells become debilitated due to the presence of these inclusion bodies, and that the cell's ability to manufacture proteins and produce energy are seriously hindered by the mitochondrial alterations and reduction in the surface density of the rough endoplasmic reticulum.

Aging and the nerve cell population of the putamen: a morphometric study

Whereas the numbers of nerve cells in several areas of the cerebral cortex are reported to decrease with aging, the fate of the neurons of the subcortical nuclei is controversial. This work is concerned with a morphometric study of the nerve cell population of the putamen through cell counting in 24 subjects aged 62 to 90 years. Our data suggest that there is no significant decline in the small-cell density with aging, nor any differences according to sex. No conclusions on the functions of the aging brain should be inferred from cell counting alone, since other signs of functional damage, such as impairment of the synapses or decrease in their number probably precede cell loss.

Effect of aging on the morphology of epididymal adipose tissue in the rat

Quantitative morphometrical parameters were compared in epididymal adipose tissue of adult (6 months old) and old (24 months old) Wistar rats, using light and electron microscopy of embedded material and freeze-etch replicas, and taking into account the functional unit of adipose tissue: the capillary-adipocyte. Despite an insignificant reduction of the adipocyte number and size in old rats when the whole population was sampled, the confounding factor of size of adipocytes could be excluded from morphometric computations in adult and old rats. Morphometric measures were performed on the whole transit from capillaries to adipocytes. They revealed that the plasma membranes, as seen in freeze etching, and the thicknesses of endothelial and adipocyte cytoplasms, as seen in ultra-thin sections, remained unaltered with aging. By contrast, the basement membranes were changed but differently around capillaries and adipocytes. The capillary-adipocyte distances were shorter and the vascularization density was higher in old rats.

Age-related reduction in 8th cervical ventral nerve root myelinated fiber diameters and numbers in man

Reduction in the number of large myelinated nerve fibers in spinal nerve roots has been described previously. We observed a reduction in myelinated nerve fiber diameters which at least in part explains the apparent marked reduction in the number of large myelinated fibers with age.

An immunohistochemical quantification of fibrous astrocytes in the aging human cerebral cortex

In order to determine whether cortical fibrous astrocytes increase with age, we studied 25 patients ranging in age from 24 to 100 years with no clinical or pathological evidence of dementia or other cerebral disorder. Paraffin sections of mid-frontal cortex were obtained and stained with the avidin-biotin immunolabeling procedure for glial intermediate filament protein. The resulting immunolabeled fibrous astrocytes were then counted in the molecular and cellular (cortical laminae 2-6) layers. Populations of fibrous astrocytes in both layers varied widely among individuals, and in the molecular layer their numbers were not significantly correlated with advancing age. In the cellular layer, however, despite widely ranging cell counts among individuals within the same decades of life, there was a significant linear increase with age. Our data suggest that the increase occurs or accelerates significantly after age 70, but the case numbers preclude reaching such a conclusion with statistical confidence. However, when the patients are divided into those less than 70 and those older, fibrous astrocytes in the cellular layer are shown to be significantly increased in the latter group compared to the former.

Cutaneous gerontology: solar degeneration of the skin

Solar elastotic syndromes are syndromes showing varied morphology of ageing effects on the skin with acceleration of the changes by the sun. Three peculiar syndromes which are less well recognised are described. These are acrokerato-elastoidosis, in which severe solar elastosis is confirmed on biopsy, colloid milium and photodermatitis--like solar degeneration with echymoses and stellate hypopigmented scars. These changes are seen in fourteen patients and often, an occupation with prolonged exposure in the sun aggravates this. Such skin changes are unlikely to be seen in future as the life style and occupations of the population change in the twenty first century.

The geriatric dental patient

The life expectancy of our citizens has increased due to better living conditions and medical care. This poses new challenges to dental surgeons because geriatric dental patients have different needs brought on by ageing. Tooth loss, periodontal disease, alveolar bone resorption, mucosal changes, edentulism are just some of the problems faced by the elderly. Recognition of the dental needs of this special category of the population compels us to bear the responsibility of treating them now and in the future. We require a gerodontology programme that emphasizes prevention, maintenance of the oral health and understanding of their psychological status.

[Results of autopsy examination of knee cartilage in 120 patients dying in the hospital. I. Femoro-patellar joint]

The authors have performed the pathological examination of the knees of 57 women and 63 men or 112 patients over the age of 50, who died in the hospital. The lesions of the patellar and trochlear cartilages were studied and classified according to four categories: stage I: non extended fissures; stage II: fissures extending over 25 p. cent of the articular surface; stage III: fissures associated with small deep ulcerations of the cartilage; stage IV: deeps and extended ulcerations of the articular cartilage exposing the sub-chondral bone. Cartilage alterations were found in 93.3 p. cent of the patellas; 26.2 p. cent of stage I; 22.5 p. cent of stage II, 27.1 p. cent of stage III; 17.5 p. cent of stage IV. These alterations are bilateral and symmetrical, most of the time. Their frequency and severity increase with age. Thus, deep and extended ulcerations (stage IV) of the patellar cartilage have a frequency of 1.9 p. cent before the age of 60.8 p. cent between 60 and 70 years, 13.6 p. cent between 70 and 80 years and 38.9 p. cent after 80 years. Alterations of the patellar cartilage are more frequent and more severe in women than in men. In 85.7 of the patellas they occupy both facets, overriding the patellar crest; more seldom, they are exclusively localized to the medial patellar facet (11.6 p. cent) or lateral facet (3.1 p. cent). Alterations of the trochlear cartilage, although more common are less frequent than that of the patellar cartilages. Patellar osteophytosis is very frequent.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of long-term running stress on the ultrastructure of the aging mouse heart

Apical regions of the left ventricular myocardium of female C57BL/6J mice, aged between 6 and 27 months, that had been subjected to endurance running for 2, 10 or 15 months, were examined by light and electron microscopy. Focal degenerative changes were found in myocytes of these experimental mice, including loss of myofibrils, erosion of myocytes and changes in nuclei, lipofuscin content and mitochondria. The interstitial connective tissue showed an increase in collagen in aged myocardia. Endurance-trained runners frequently showed signs of platelet aggregation or microthrombi in small capillaries associated with myocytes. These were most common in endurance-trained middle-aged and very elderly mice, but were not found in sedentary age-matched controls. Our experiments indicate that running stress may be damaging to cardiac tissue in aged animals. Our findings may be of significance in helping the understanding of the development and the etiology of stress-induced cardiovascular damage in the elderly.

Maxillary suture obliteration: aging the human skeleton based on intact or fragmentary maxilla

Obliteration of the four sutures of the bony palate is examined to determine its value as an age indicator. Thirty-six maxillae from a predominately white series representing both sexes and a wide variety of ages are studied. It is concluded that the amount of obliteration of these sutures is useful in estimating general biological age.

A comparative study of the effect of age on the human cochlear and vestibular neuroepithelia

A semi-quantitative and semi-qualitative comparative analysis was performed on the maculae and cochleas of 3 patients. The cochleas were examined by SEM and the maculae by TEM and light microscopy. The surface features of the cochleas were minimally affected by autolysis. Hearing loss and increasing age correlated well with inner and outer hair cell counts. In the labyrinth, the sacculi were more resistant to autolysis than were the utriculi and the type 2 cells better preserved than the type 1 cells. The pattern of cellular degeneration in the utriculus and sacculus varied with both age and functional deficit. Lipofuscin was present in the sensory cell of all 3 patients but was most pronounced in the oldest. Long-spaced collagen, laminated bodies and membrane-bound inclusions were seen in all maculae.

Characterization of the choroidal mast cell

The experimental studies performed on nonpigmented rat choroids and the review of the important literature covered in this thesis seem to justify the following statements: 1. Mast cells are present in the choroid in significant numbers. 2. Mast cell numbers vary considerably from one individual to another and from one location in the choroid to another. 3. The major concentration of mast cells in the uvea is in the posterior choroid. 4. The mast cells of the choroid have a preferential location along arterial vessels. 5. Choroidal mast cell population density apparently decreases with senescence. 6. Mast cell products are present in sufficient quantity to exert substantial effects on physiologic, immunologic, and inflammatory responses in the choroid. 7. Choroidal mast cell products are released with appropriate stimulation and share some properties with the connective-tissue mast cell. 8. Choroidal mast cell demonstrate enough differences to suggest that a local differentiation may be present and may represent a locally controlled modulating effect for choroidal physiologic, immunologic, and inflammatory reactions.

Degeneration of hippocampal fibers and spatial memory deficit in the aged rat

Old and young Fisher 344 rats were compared for their ability to learn a delayed alternation task. The old animals displayed significant impairment of alternation learning, and were slower than the young animals. The brains of these animals were examined using a silver degeneration stain, and among old rats there was conspicuous degeneration. The greatest density of degenerating fibers was seen in the hippocampus and in anatomically related tracts, but there was substantial fiber staining in the corpus callosum, anterior commissure, and internal capsule. Examination of the young brains revealed only an occasional fiber. There were no signs of cortical atrophy in the old animals. The histopathology of the aged animals' hippocampus and fiber tracts supports the possibility that the delayed alternation impairment shown by these animals was a result of age related degenerative changes.

Atrophy of the cerebellar vermis in ageing. A morphometric and histologic study

Morphometric analysis of the cerebellar vermis in 67 non-alcoholic men between 36 and 94 years of age showed a significant decline in Purkinje cell densities with increasing age in all parts of the cerebellar vermis. However, the nerve cell loss was much more severe in the superior than in the inferior part. There were large individual variations and one-half of the subjects over 80 years showed densities similar to those in the sixties. By independent evaluation, atrophy of the superior vermis was diagnosed histologically in 16 cases, 13 of whom were over 70 years of age. There was a good correspondence between the histologic diagnoses and the morphometric findings. The atrophy involved all 3 cortical layers and the changes were identical to those seen in alcoholics. The diagnosis of alcoholic cerebellar atrophy must therefore be made with great caution in subjects over 70 years of age. Cases with malignant tumours had significantly lower Purkinje cell densities in the superior vermis than those without tumours but the decline with age was of the same magnitude in the 2 groups. The age-dependent atrophy of the superior vermis seemed to be correlated to age alone and not to other known conditions. It probably was sufficiently severe to be recognized radiologically and clinically in a considerable number of the cases.

[The normal range of cerebral atrophy during aging: statistical analysis of 500 normal subjects]

We previously reported the newly developed quantitative measurement of the cerebral atrophy (pixel count method), and advocated the value CCR (CSF-cranial ratio) as the index of the volumetric measurement of the cerebral atrophy. As the pixel count method is somewhat troublesome, we tried to compare the various linear measurement methods with pixel count method by means of multivariant analysis, and reported a single formula to calculate CCR from the linear measurement methods. Now we studied 500 normal subjects using the pixel count method and examined the normal range of the cerebral atrophy during aging by means of the maximum likelihood method. The normal range was estimated as follows; 0.32 less than y less than 5.78 (t less than 48), 0.068 t--2.944 less than y less than 0.368 t--11.884 (t greater than 48). Using these formula and this newly reported normal range, we can easily predict whether the cerebral atrophy is pathological or not.