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Somatofugal axonal atrophy precedes development of axonal degeneration in acrylamide neuropathy.

Somatofugal axonal atrophy is part of the neuronal perikaryal response to axonal injury (axon reaction). Chronic administration of acrylamide (AC) produces proximal atrophy in virtually all sensory fibers in lumbar dorsal root ganglion (DRG) despite the presence of many intact axons in the distal portion of the sciatic nerve. This suggests that the development of axonal atrophy in AC-intoxicated animals is not solely due to a toxic chemical-induced axonal degeneration (axotomy). In this study, we asked whether axonal atrophy arises before onset of axonal degeneration. Rats were given a single intraperitoneal (i.p.) high dose of AC (75 mg/kg), which blocks retrograde axonal transport, followed by daily intraperitoneal injections (30 mg/kg, for 4 days). At 5 days, sensory fibers in the L4 and L5 DRG appeared smaller in caliber and less circular in shape compared to fibers from age-matched normal animals. Axonal diameters of sensory fibers in the L5 dorsal root were significantly (p less than 0.05) reduced at distances up to 2 mm from the DRG. Quantitative electron microscopy demonstrated that the reduction in caliber was due to a decreased neurofilament (NF) content. Axonal degeneration was not present in the distal portion of both centrally (dorsal root) and peripherally (sciatic nerve) projecting sensory fibers at this time, although primary afferent terminals in muscles of the hindfeet were packed with NFs. The somatofugal progression of the atrophy was evident following more prolonged exposures (10-28 days). It is suggested that AC produces somatofugal axonal atrophy by inhibiting the delivery of a retrogradely transported target-derived "trophic" signal to the neuronal perikaryon.

Acrylamide

The significance of cerebral atrophy for the symptomatology of Parkinson's disease.

Hitherto published results on the impact of brain atrophy on the neurological and psychopathological sympion of this problem without risk of complications. We investigated 173 parkinsonian patients (89 men, 84 women) aged 37--83 years. Besides CT in all patients a standardized neurological and psychopathological investigation was carried out, including psychological tests, intelligence, personality structure, fine motor performance and visual reaction times. The investigations revealed pronounced correlations between CT-findings and more severe clinical symptomatology and a corresponding impairment in daily activities in the levodopa-treated and particularly in the untreated group, above all when there was a combination of cortical atrophy and ventricular enlargement. The same was true for fine motor performance and simple and complex reaction times. These functions were more impaired in patients with brain atrophy, irrespective of its localisation, whether cortical atrophy or ventricular enlargement. In contrast, no statistically significant relationship between the different parameters of brain atrophy and intelligence could be found. Considering cortical atrophy as a specific sign in Parkinson's disease -- our results are in favour of this assumption -- and ventricular enlargement more related to increasing age, parkinsonism is influenced by extranigral lesions inherent in the disease and dependent on increasing age.

Adult

Relationship between corpus callosum atrophy and cerebral metabolic asymmetries in multiple sclerosis.

Corpus callosum (CC) atrophy by magnetic resonance imaging (MRI) is a common finding in multiple sclerosis (MS). In order to examine the relationship between CC atrophy and cortical brain metabolism, we compared the cerebral metabolic rates for glucose (CMRglc), measured by positron emission tomography (PET), of 8 MS patients with evidence of CC atrophy on midsagittal MRI, 8 MS patients without CC atrophy and 10 healthy controls. Results showed no significant differences in supratentorial CMRglc absolute values between the three groups, although a slight metabolic reduction was observed in both MS groups compared with normal controls. By contrast, only patients with CC atrophy showed greater directional metabolic asymmetry than normals, the left frontal, temporal and parietal association cortices being significantly lower than the right. Predominant left hemispheric metabolic reductions were not accompanied by a corresponding left-sided predominance in the extent of MRI-detected demyelinating lesions. Therefore our data suggest that CC atrophy interfers more with left than with right metabolic function.

Adult

The relationship between apoptosis and atrophy in the irradiated lacrimal gland.

Atrophy is generally considered to be a true late effect of radiation. However, in serous glands, atrophy was thought to be a consequential late effect because serous cells die within hours of irradiation and the apparent effects of atrophy are observed contemporaneously with radiation treatment. Therefore, to determine the pathogenesis of atrophy in serous glands, it is necessary to differentiate between parenchymal loss as a result of direct radiation death of serous cells and parenchymal loss as a result of serous cell death that is secondary to fibrosis, vascular damage, or precursor cell death. The lacrimal glands of 62 rhesus monkeys have been irradiated to single doses of 2.5 to 20 Gy and examined at intervals of 4 hr to 112 days postirradiation. Serous cells (nuclei) and acini were counted in at least 30 high power fields per (dose, time) point. At each dose and time of sacrifice, the average number of nuclei per acinus and the average number of acini per high power field were calculated. Also at each dose and time, the distribution of the number of nuclei per acinus was examined to determine how the frequency of acinar sizes changed as a function of irradiation. The number of cells per acinus appears to rise initially, but this is likely a result of the degranulated cells being physically smaller, yielding an artificially higher count. Within 4 days after 12.5 Gy, the average number of nuclei per acinus approaches control values and remains within the range of controls for at least 112 days. The number of acini per high power field decreases steadily for 30 days after 12.5 Gy. From 30 to 112 days, there is some recovery of this number, but it remains well below control values. At 24 hr, the number of nuclei per acinus shows a distinct dose response up to 20 Gy. However, at 30 days there is no evidence of a dose response for this parameter. These results indicate that even though serous cells die in significant numbers within hours of irradiation, the atrophy of the lacrimal gland (and by extension, the parotid gland) is a result of the death of the serous stem cell or precursor. Consequently, protection of serous cells from radiation apoptosis will not diminish serous gland atrophy.

Animals

The effect of disuse muscular atrophy on the forces generated in dynamic exercise.

1. Six patients were studied after prolonged immobilization of an injured leg resulting in muscle atrophy. 2. The forces exerted by the atrophied and normal legs during continuous dynamic exercise (one- and two-leg cycling) were examined by a specially adapted ergometer. 3. In one-leg cycling the peak force exerted on the crank at a given work rate, the net work rate performed on the crank, and the proportion of work rate performed in leg extension and flexion phases of the cycle were the same whether the atrophied or normal limb was used. 4. Despite these similarities there was an unexplained reduction in efficiency when using the atrophied leg to perform one-leg cycling. 5. In two-leg cycling the peak force exerted at a given work rate by the atrophied leg was reduced by about 40% as compared with the normal leg, which reflected a similar reduction in the contribution of that leg to the total net work rate. Possible reasons and implications for this disproportionate sharing of work between the normal and atrophied leg are discussed.

Adult

Post-menopausal atrophy in elderly women: is a vaginal smear necessary for diagnosis?

The diagnosis of post-menopausal atrophy should preferably be confirmed before any trial of oestrogen treatment for genito-urinary symptoms. The ideal method, cytological analysis of a vaginal wall smear, is not always feasible in elderly women. Might physical examination alone be sufficient? This study aimed to determine which clinical features might best predict atrophy on the smear. Of 120 consecutive women admitted to an acute geriatric unit (mean age 82 years), satisfactory smears were obtainable from 70 (58%). Sixty per cent of these showed severe atrophy but almost one-fifth showed no atrophic changes. Degree of atrophy correlated with physical thinness (p less than 0.01), low parity (p less than 0.01) and dryness on vaginal examination (p less than 0.001). However, none of the other physical findings traditionally thought to indicate atrophy were found to be associated, nor were age or medication. In contrast, severe atrophy was present in only one of nine women with breast cancer (p less than 0.01). This merits further study.

Aged

Fine structure of muscle in human disuse atrophy: significance of proximal muscle involvement in muscle disorders.

The universal occurrence of weakness of skeletal musculature on disuse, however produced, and the paucity of published reports on the fine structural changes in human disuse atrophy, prompted the present investigation. The quadriceps muscle of a leg immobilized in plaster cast (for fracture) and of the opposite non-immobilized limb was biopsied in four adult males, after periods of immobilization from 50 to 75 days. These 8 muscle specimens were examined for histopathological changes, and muscle fibre diameters were measured by micrometry from paraffin sections. The histograms revealed a larger proportion of small fibres (less than 20 micron) and a smaller proportion of large fibres (greater than 40 micron) in the immobilized limb compared to the opposite. Thus, light microscopy showed only atrophic changes. This was confirmed by electronmicroscopy, where atrophy of few to several muscle fibres was seen in the form of loss of myofibrils, collapse and folding of the basement membrane and prominence of glycogen or muscle nuclei. The atrophic change was more severe in the immobilized limbs, but it was also noticeable in all the non-immobilized limbs. Degenerative changes, especially disorganization and breakdown of myofibrils, and fragmentation of plasma membrane, were also seen in occasional atrophied muscle fibres, again more frequently in the immobilized limb. Lipofuscin was often found accumulated in muscle fibres and occasionally in endothelial cells of intramuscular blood vessels; the latter showed prominent pinocytotic vesicles or thickened basement membrane. It is concluded that both atrophy and degeneration of fibres of proximal muscles can occur as non-specific consequences of disuse of the limb in man, that degeneration is a latter and more severe change, that muscles even of the non-immobilized leg are subjected to disuse atrophy during bed-rest, and that the proximal muscles in man seem to have a natural susceptibility to atrophy and degeneration in any muscular disorders.

Adult

Brain atrophy and intellectual impairment in heavy drinkers--a clinical, psychometric and computerized tomography study.

The frequency of cerebral and cerebellar atrophy was assessed by computerized tomography (CT) in 26 heavy drinkers. Findings were correlated with clinical deficits, with the results of psychometric testing using the Wechsler Adult Intelligence Scale (WAIS), and with the alcoholic history and nutritional status. Cerebral atrophy was present in 19 cases (73%), 16 of whom also had cerebellar atrophy. There was a good correlation between the degree of cerebral hemisphere atrophy and age and length of drinking history, but a poor correlation between neurological deficits and atrophy. Impairment of visuo-spatial and visuo-motor functions with sparing of other non-dominant hemisphere functions and of verbal skills was the characteristic pattern found with the WAIS in 18 subjects; four showed a more global depression of intellectual function. The degree of cerebral hemisphere atrophy correlated significantly with the impairment of non-dominant hemisphere functions but not with total IQ.

Adult

Atrophy of optic nerve fibres in compression of the chiasm. Prognostic implications.

A relationship between the degree of atrophy of retinal nerve fibres and visual field defect has been described in postoperative steady-state patients (Lundström & Frisén 1976). The same factors were studied prior to surgery in six patients with compression of the chiasm due to chromophobe adenoma. In five eyes the field defect was excessive in relation to the degree of atrophy. After surgery the visual field defects improved to a level corresponding to the degree of atrophy in these eyes. In the remaining seven eyes there was a close correspondence between the atrophy and the visual field defect already before surgery. The visual field defects remained unchanged in these eyes. Provided that atrophy does not increase after surgery, simultaneous preoperative evaluation of retinal nerve fibre atrophy and visual field defect allows an accurate prediction of prognosis for improvement.

Adenoma, Chromophobe

Trace element movement and oxidative stress in skeletal muscle atrophied by immobilization.

The movements of trace elements and the level of oxidative stress in the soleus, a typical slow red muscle which, atrophied by immobilization, were investigated in designated intervals. Male Wistar rats (14 wk old) whose one ankle joints were immobilized in the extended position were killed after 4, 8, and 12 days. Fe, Zn, Mn, and Cu concentrations and the levels of thiobarbituric acid-reactive substance (TBARS) and glutathione were measured. The rate of atrophy increased rapidly until the 8th day and slowly after that. In whole muscle, Fe concentration kept increasing, and Zn and Mn increased temporarily. Their subcellular distributions also changed; especially, the Fe level of the microsomal fraction kept increasing and reached threefold at 12 days. Increased TBARS and glutathione disulfide and decreased total glutathione indicated the increased oxidative stress in atrophy, which might result from an increased Fe level, especially that of the microsomal fraction. Vitamin E injection lessened the rate of atrophy, which showed that oxidative stress accelerated muscle atrophy. This might be mediated by increased intracellular Ca. Also metallothionein was induced in muscle atrophy.

Animals

Do hormonal (stress) and vascular (ischaemia) factors contribute to reflex muscle atrophy induced by chronic nociceptive stimulation in rats?

1. Reflex muscle atrophy was induced in rats by fracturing the metatarsal bones of one hind paw and injecting 0.02 ml turpentine oil into the planta under shortlasting ether anaesthesia. The atrophy thus evoked in the soleus and extensor digitorum longus (EDL) was compared with the contralateral muscles. 2. There was a twelvefold increase of plasma corticosteroid levels one hour after application of the above nociceptive stimulus and the levels were still somewhat enhanced at 3 days. Neither bilateral adrenalectomy nor administration of corticosteroid hormones or cold stress affected the development of reflex atrophy. 3. Restriction of the arterial blood supply (ligature of the common iliac artery) led to a slowly progressing atrophy with a maximum 10 days after the ligature. Reflex atrophy introduced at different times after ligature was not enhanced. 4. These results are interpreted as evidence that neither general stress (and the effect of catabolic hormones) nor local restriction of muscle blood flow (by reflex vasospasm, for example) are likely to play any appreciable role in the mechanism of reflex muscle atrophy.

Adrenal Cortex Hormones

Testicular atrophy and impaired spermatogenesis in rats fed high levels of the methylxanthines caffeine, theobromine, or theophylline.

Experiments were designed to determine the effects of feeding the methylxanthines caffeine, theobromine, or theophylline to 4- to 6-week-old males rats at a dietary level of 0.5 percent for periods ranging from 14 to 75 weeks. In the first two experiments, Osborne-Mendel rats were fed the test substances alone or in combination with sodium nitrite to test the hypothesis that these amines might nitrosate in vivo to produce toxic nitrosamine compounds. The compounds failed to produce neoplastic or preneoplastic lesions, but a significant positive finding was the occurrence of severe bilateral testicular atrophy with aspermatogenesis or oligospermatogenesis in 85-100 percent of the rats fed caffeine or theobromine. In a third experiment the methylxanthines were fed to Holtzman rats for 19 weeks to determine whether testicular atrophy would be induced in a second strain of rat. The testicular effects were similar to those in Experiments I and II but were more pronounced. Caffeine and theobromine induced testicular injury in nearly all rats. Theophylline induced severe testicular atrophy in 14 percent of the rats, mild to moderate atrophy in 71 percent, and had no effect in 15 percent. The relative testicular toxicity of the methylxanthines was caffeine, most potent; theobromine, slightly less potent; and theophylline, considerably less potent. Somewhat variable atrophic changes of the accessory sexual organs (epididymis, prostate, and seminal vesicles) accompanied the testicular changes. Cytogenetic analysis of testes from caffeine- or theophylline-treated rats revealed a significantly reduced number of mitotic cells in the caffeine-treated group. Plasma testosterone concentrations were significantly elevated in the theobromine group and somewhat elevated in the caffeine-treated group; this correlated morphologically with an apparent hyperplasia of interstitial cells in severely atrophied testes in these groups. Plasma cholesterol concentrations were significantly increased in the caffeine and theobromine groups. Possible sites and mechanisms of action of the methylxanthines in the induction of testicular atrophy and impaired spermatogenesis are discussed.

Animals

Testicular atrophy and impaired spermatogenesis in rats fed high levels of the methylxanthines caffeine, theobromine, or theophylline.

Experiments were designed to determine the effects of feeding the methylxanthines caffeine, theobromine, or theophylline to 4- to 6-week-old male rats at a dietary level of 0.5 percent for periods ranging from 14 to 75 weeks. In the first two experiments, Osborne-Mendel rats were fed the test substances alone or in combination with sodium nitrite to test the hypothesis that these amines might nitrosate in vivo to produce toxic nitrosamine compounds. The compounds failed to produce neoplastic or preneoplastic lesions, but a significant positive finding was the occurrence of severe bilateral testicular atrophy with aspermatogenesis or oligospermatogenesis in 85-100 percent of the rats fed caffeine or theobromine. In a third experiment the methylxanthines were fed to Holtzman rats for 19 weeks to determine whether testicular atrophy would be induced in a second strain of rat. The testicular effects were similar to those in Experiments I and II but were more pronounced. Caffeine and theobromine induced testicular injury in nearly all rats. Theophylline induced severe testicular atrophy in 14 percent of the rats, mild to moderate atrophy in 71 percent, and had no effect in 15 percent. The relative testicular toxicity of the methylxanthines was caffeine, most potent; theobromine, slightly less potent; and theophylline, considerably less potent. Somewhat variable atrophic changes of the accessory sexual organs (epididymis, prostate, and seminal vesicles) accompanied the testicular changes. Cytogenetic analysis of testes from caffeine- or theophylline-treated rats revealed a significantly reduced number of mitotic cells in the caffeine-treated group. Plasma testosterone concentrations were significantly elevated in the theobromine group and somewhat elevated in the caffeine-treated group; this correlated morphologically with an apparent hyperplasia of interstitial cells in severely atrophied testes in these groups. Plasma cholesterol concentrations were significantly increased in the caffeine and theobromine groups. Possible sites and mechanisms of actions of the methylxanthines in the induction of testicular atrophy and impaired spermatogenesis are discussed.

Animals

A family with Charcot-Marie-Tooth disease and Leber's optic atrophy.

A family has been studied in which members of 4 generations were affected by the hypertrophic type of Charcot-Marie-Tooth disease. The diagnosis was confirmed by electrophysiological studies and by sural nerve biopsy. 10 members of the family, 8 males and 2 females, developed optic atrophy of acute onset with progression over a period of two to six months. The history of visual failure, its maternal inheritance, and the neuro-ophthalmological findings of optic atrophy with bilateral central scotomata were typical of Leber's optic atrophy. 2 members of the family suffered from both Charcot-Marie-Tooth disease and Leber's optic atrophy. There have been a few previous reports of optic atrophy associated with Charcot-Marie-Tooth disease, and in the present family both conditions appeared to have been inherited independently.

Adolescent

Dominant spinopontine atrophy. Report of two additional members of family W.

In five generations of Anglo-Saxon family W, 28 members were affected with dominant hereditary ataxia. In 1969, two members of this family were reported as prototypes of dominant spinopontine atrophy. We discuss two additional members of the original family, with one postmortem examination, including ultrastructual study. In contrast to previously accepted clinical generalizations, we found abolished tendon reflexes and flexion contractures of the lower extremities in patient 1 and onset of illness at the age of 18 years, palatal myoclonus, and optic atrophy in patient 2. Dementia was observed in both patients. Unlike in previous pathological reports, our patient 1 showed definite involvement of the cerebellum and mild degeneration of the inferior olivary nuclei. We conclude, therefore, that clinical and pathological distinction between dominant spinopontine atrophy and olivopontocerebellar atrophy is not clear and raises the question of the justification for regarding dominant spinopontine atrophy as a nosological entity.

Adult

Immobilization-induced muscle atrophy is not reversed by lengthening the muscle.

In clinical practice, repaired tendocalcaneus (Achilles tendon) ruptures are often protected in immobilization casts for 4 weeks in the fully plantar flexed position and for up to another 4 weeks after returning the ankle to joint neutral. Moderate to severe muscle atrophy occurs within 4 weeks of immobilization in plantar flexion, but it is not known if this atrophy is minimized or reversed following restoration of joint neutral position. We tested the hypothesis that the extent of atrophy could be reduced by returning the ankle to joint neutral after 4 weeks of immobilization. Eighteen rabbits were anesthetized, and their right hind-limbs were casted with the knee flexed 90 degrees and the ankle fully plantar flexed. Three animals each were studied after 3, 4, 6, or 8 weeks of immobilization. After 4 weeks of immobilization, the immobilization casts of the remaining six rabbits were modified to return the ankle to joint neutral for another 2 or 4 weeks. For muscle studies, the animals were anesthetized, and the soleus (SOL), plantaris (PLN), and gastrocnemius (GST) muscles were removed and weighed; the SOL and PLN were quick frozen and processed for histochemical fiber typing and fiber cross-sectional area measurement. All three muscles showed significantly reduced muscle weight to body weight ratios after 3 weeks of immobilization. SOL was the most affected, and GST was least affected. There was no significant further atrophy through 8 weeks of immobilization. The atrophy correlated with a significant reduction of mean fiber area (MFA) for Types I, IIo, and IIc fibers in SOL and PLN. In PLN, Type IIg fiber area was not significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Differentiation of normal pressure hydrocephalus and cerebral atrophy by computed tomography and spinal infusion test.

The diagnostic value of computed tomography (CT) and spinal infusion test (SIT) was investigated in 27 patients with normal pressure hydrocephalus (NPH) and 35 patients with cerebral atrophy. The most consistent CT finding of NPH was dilatation of the temporal horns, that of cerebral atrophy widening of the convexity sulci. However, 43% of patients with cerebral atrophy demonstrated no cortical atrophy. The SIT showed an excellent relation with isotope cisternography and continuous intracranial pressure recording. NPH and cerebral atrophy were correctly differentiated in 71% by CT and SIT. A normal SIT and a CT scan without the typical features of NPH exclude impairment of cerebrospinal fluid absorption. An abnormal SIT and a CT scan showing ventricular enlargement without dilatation of convexity sulci, require isotope cisternography and possibly intracranial pressure recording to determine the degree of the absorption deficit.

Atrophy

Relationship between arteriosclerosis and cerebral atrophy in Parkinson's disease.

Computed tomographic examinations of parkinsonian patients revealed a high incidence of cerebral atrophy, in most cases a combination of cortical atrophy and ventricular enlargement. The present study considered the relationship between cerebral atrophy and physical signs indicating or promoting arteriosclerosis such as overweight, electrocardiographic changes, hypertension, calcification of the internal carotid artery and aorta as well as elongation of the aorta. The study is based on 173 treated and untreated parkinsonian patients (89 men, 84 women) aged from 37--84 years (mean 64.6), on whom CT was performed about 5.4 years after the onset of the first symptoms of the illness. The results demonstrate an increase of pathological CT findings as well as of calcification in the carotid siphon with advanced age. No correlation was found between the other items and increasing age. Further analysis of the relationship between cerebral atrophy and signs of arteriosclerosis revealed only a statistically relevant correlation with calcification of the carotid siphon, especially with calcification of the media. Since pathological CT findings and calcification of the internal carotid artery are both related to advanced age, whereas all the other items which may be considered to be indications of arteriosclerosis do not have any clear relationship, it is concluded that the cerebral atrophy in Parkinson's disease is not caused by arteriosclerosis.

Adult