Psychophysical power functions for apparent area in perceptive, memory, and inference conditions for observers of different age groups

The purpose of this research was to verify the effect of age on the exponent of the power function in Perceptive, Memory, and Inference experimental conditions. In the Memory condition the intervals of 2 min., 8, 24, and 48 hr. and 1 wk. were used between acquisition of information and remembering. For each experimental condition the ages of observers ranged between 17 and 35 years (Group I), 40-55 years (Group II), and 60-77 years (Group III), and education ranged from high school to graduate school. The observers estimated the areas of the Brazilian satires using the psychophysical method of magnitude estimation. No significant differences were obtained for Groups I, II, and III for each experimental condition, except in the Memory Condition with the 24-hr. interval. Analysis for experimental conditions and ages showed a significant difference between the Perceptive Condition and each of the others, but no difference between the Inference and Memory Conditions. These results indicated that in the remembering processes there is no loss of information as a function of age. From the small variability in the power function exponents for the three ages, we may assume that age could be related to amount of education of the observers, which suggests study is important.

Optimizing glucocorticoid therapy in rheumatoid arthritis

Glucocorticoids have a profound effect on the immune system and also on the HPA axis. Present insights into these mechanisms are discussed. Glucocorticoid resistance and clinical efficacy in the treatment of RA are reviewed. There is growing evidence for a positive effect of low-dose glucocorticoids on the retardation of erosive joint damage. Side effects of glucocorticoids on bone are now better controlled. Some guidelines to optimize glucocorticoid therapy in RA are given regarding dosage, timing, managing of side effects, and (new) types of glucocorticoids.

[Primary intracerebral hemorrhage. Retrospective study of 72 operated cases]

We analysed 72 cases of primary intracranial hemorrhage surgically treated from 1970 to 1999. The hemorrhages were diagnosed by computerized axial tomography in 52 patients. Most hematomas were situated in the cerebral hemispheres (30 percent in thalamus-basal ganglia region and 50 percent in the subcortical matter). There were 10 patients with cerebellar hemorrhage. Hypertension (based in blood pressure recordings in the hospital and history) was found in 24 patients (33 percent). The most frequent findings were coma, intracranial hypertension and hemimotor deficit. The death rate registered was 27.7 percent; however, it was found a significant difference in the mortality index when considering the 70-79 decade (62.7 percent) and the 90-99 decade (20.7 percent). A critical analysis was made about depth hematomas, consciousness state and intracranial hypertension with herniation related to surgical procedure.

[Transitory cerebellar mutism: report of 2 cases]

We present two cases of mutism observed after resection of tumors of the cerebellum, in two children of the feminine sex, being in the first case of medulloblastoma and in the second of juvenile astrocytoma. In both patients there was pre-operative lesion of low cranial nerves. The pathophysiology of the mutism involves anatomical, vascular and emotional factors, being its essential characteristics discussed with base in revision of the literature.

Sex hormones and glucocorticoids: interactions with the immune system

Gender and sex hormones exert powerful effects in the susceptibility and progression of numerous human and experimental autoimmune diseases. This has been attributed to direct immunological effects of sex hormones that impact a clear gender dimorphism on the immune system. Globally, estrogens depress T cell-dependent immune function and diseases, but enhance antibody production and aggravate B cell-dependent diseases. Androgens suppress both T-cell and B-cell immune responses and virtually always result in the suppression of disease expression. Defects in the hypothalamic-pituitary-adrenal (HPA) axis have been proposed to play an important role in the pathogenesis of autoimmune diseases. Glucocorticoid response to stress, including immune challenge, is strongly inhibited by androgens and enhanced by estrogens. Complex three-way interactions between these systems appear to be involved in gender dimorphism of the immune system. This paper reviews the mechanisms involved in interactions between sex steroids and the HPA axis, addresses the possibility of similar interactions on immunocompetent cells, and explores an integrated perspective of the impact of these interplays on the immune system.

Destruction of articular cartilage by alpha 2 macroglobulin elastase complexes: role in rheumatoid arthritis

OBJECTIVE

Neutrophil elastase accounts for the ability of some fresh rheumatoid synovial fluids to degrade cartilage matrix in vitro. The aim of this study was to determine if enzyme activity could result from depletion of synovial fluid inhibitors or protection of the enzyme from inhibition.

METHODS

The ability of synovial fluids to inhibit porcine pancreatic elastase was investigated together with chemical pretreatments capable of inactivating alpha 1 protease inhibitor (alpha 1PI) or preventing formation of alpha 2 macroglobulin (alpha 2M) elastase complexes. Subsequently, complexes of human neutrophil elastase with alpha 2M were prepared and applied to frozen sections of cartilage. Proteoglycan loss was quantified by alcian blue staining and scanning and integrating microdensitometry. Parallel studies were carried out using a low molecular weight chromogenic elastase substrate. The effects of alpha 1PI and SF on these systems were investigated. Finally, synovial fluids were subjected to gel filtration and the fractions assayed for elastase activity. High molecular weight fractions were pooled, concentrated, and tested for their ability to degrade cartilage sections.

RESULTS

All synovial fluids reduced the activity of porcine pancreatic elastase, the inhibition mainly being attributable to alpha 1PI, whereas remaining activity resulted from complexes of elastase with alpha 2M. Complexes of human neutrophil elastase with alpha 2M were shown to cause proteoglycan degradation in frozen sections of human articular cartilage. Alpha 1PI prevented alpha 2M elastase complexes from degrading cartilage but not the chromogenic substrate. The data suggested that alpha 1PI does not inhibit elastase bound to alpha 2M but sterically hinders the complex. However, only one of five synovial fluids was able to completely block the actions of alpha 2M elastase complexes against cartilage. Gel filtration of rheumatoid synovial fluids showed elastase and cartilage degrading activity to be associated with fractions that contained alpha 2M, and not with fractions expected to contain free enzyme.

CONCLUSIONS

The data suggest that synovial fluid alpha 2M elastase complexes can degrade cartilage matrix in rheumatoid arthritis.

[Isolated fourth ventricle: report of 2 cases]

Two cases of isolated fourth ventricle are reported, the first due to cerebellar haemorrhage, and the second due to congenital hydrocephalus with multiple shunt revisions and Dandy-Walker cyst. In our opinion, there are two basic treatment for isolated forth ventricle. The direct approach to the fourth ventricle is indicated when there is presence of an intraventricular cyst. The fourth ventricular shunting, independent of the supratentorial shunt, is the best treatments for patients with an isolated fourth ventricle without the presence of a cyst.

Visual perception of egocentric distance as assessed by triangulation

Two triangulation methods for measuring perceived egocentric distance were examined. In the triangulation-by-pointing procedure, the observer views a target at some distance and, with eyes closed, attempts to point continuously at the target while traversing a path that passes by it. In the triangulation-by-walking procedure, the observer views a target and, with eyes closed, traverses a path that is oblique to the target; on command from the experimenter, the observer turns and walks toward the target. Two experiments using pointing and 3 using walking showed that perceived distance, averaged over observers, was accurate out to 15 m under full-cue conditions. For target distances between 15 and 25 m, the evidence indicates slight perceptual underestimation. Results also show that observers, on average, were accurate in imaginally updating the locations of previously viewed targets.

Visual perception of egocentric distance as assessed by triangulation

Two triangulation methods for measuring perceived egocentric distance were examined. In the triangulation-by-pointing procedure, the observer views a target at some distance and, with eyes closed, attempts to point continuously at the target while traversing a path that passes by it. In the triangulation-by-walking procedure, the observer views a target and, with eyes closed, traverses a path that is oblique to the target; on command from the experimenter, the observer turns and walks toward the target. Two experiments using pointing and 3 using walking showed that perceived distance, averaged over observers, was accurate out to 15 m under full-cue conditions. For target distances between 15 and 25 m, the evidence indicates slight perceptual underestimation. Results also show that observers, on average, were accurate in imaginally updating the locations of previously viewed targets.

A randomized trial of testosterone therapy in males with rheumatoid arthritis

Thirty-five male patients, aged 34-79 yr, with definite rheumatoid arthritis (RA) were recruited from out-patient clinics and randomized to receive monthly injections of testosterone enanthate 250 mg or placebo as an adjunct therapy for 9 months. Endpoints included disease activity parameters and bone mineral density (BMD). At baseline, there were negative correlations between the ESR and serum testosterone (r = -0.42, P < 0.01) and BMD (hip, r = -0.65, P < 0.01). A total of 29.6% of all patients had at least one vertebral fracture, most having multiple fractures. Back pain, however, was not more prevalent in fracture patients (55% vs 50%). Disease activity was significantly higher in the fracture group (joint score P < 0.05, rheumatoid factor P < 0.01). Thirty patients completed the trial, 15 receiving testosterone and 15 receiving placebo. There were significant rises in serum testosterone, dihydrotestosterone and oestradiol in the treatment group. There was no significant effect of treatment on disease activity overall, five patients receiving testosterone underwent a "flare'. Differences in mean BMD following testosterone or placebo were non-significant (spine: +1.2% vs -1.1%; femur: -0.3% vs +0.3%). There was no suggestion of a positive effect of testosterone on disease activity in men with RA.

Perturbations of hypothalamic-pituitary-gonadal (HPG) axis and adrenal androgen (AA) functions in rheumatoid arthritis

The available evidence reviewed does not allow definitive response to the question of a primary versus secondary role of sex hormone perturbations in RA. However, this conclusion should not be discouraging in view of the relatively recent focus upon this facet of the physiopathogenesis of RA and the enormous complexities of sex hormone biology and this disease. Specifically, data on the incidence of RA as well as life cycle changes in serum androgenic-anabolic (A-A) and sex hormone levels suggest important risk correlations. Furthermore, HLA-susceptibility markers for RA, gender, menopause and older age are all factors which significantly relate to the risk of developing RA and each has been shown to associate with sex hormone status. Whether or not HPG-AA hormonal status may modulate RA risk (or its course) primarily and independently or merely be predictive markers of other biological mechanisms was critically considered and requires further study. Sex hormone influences on cellular and humoral immunological reactivity and vascular pathogenetic mechanisms in RA were summarized. Androgens generally suppress immunoreactivity and cartilage responses to inflammation-mediated injury processes and may enhance synovial macrophage-like lining cell apoptosis. Oestrogens generally enhance immunoreactivity, offer some protection to inflammation-mediated cartilage damage (but less than androgens) and may inhibit apoptosis in certain in vitro cell models. Scant information is available on the balance of sex hormones (and glucocorticoids) in RA or its presumed pathogenetic mechanisms. Data were reviewed which support the concept of a spectrum of androgenicity in the normal population, particularly among women. A simplified schema of trophic and tropic steroidogenic mechanisms was proposed which could influence androgenic-anabolic (A-A) status and might relate to RA. Serum concentrations of DHAS (mumol/l), T (nmol/l) and O2 (pmol/l) span several orders of magnitude in normal physiology. The effects of alterations in the individual levels of these sex hormones and deviations from their normal physiological balance are not well understood. Critical attention to their biological functions is needed in RA as well as in health and disease generally. Such focused clinical and experimental investigations of HPG-AA functions promise to clarify the complex physiopathology of RA and contribute to its improved long-term management.

Direct degradation of articular cartilage by rheumatoid synovial fluid: contribution of proteolytic enzymes

OBJECTIVE

To test the effects of synovial fluids (SF) on human cartilage in an in vitro model.

METHODS

Freshly collected SF were incubated with cryostat sections of articular cartilage, and glycosaminoglycan (GAG) loss determined by microdensitometry after alcian blue staining.

RESULTS

Of 20 rheumatoid SF, 11 induced significant GAG loss compared with only 3 out of 15 osteoarthritic SF. The effect of rheumatoid fluids appeared to be related to disease activity. GAG loss was partially prevented by a broad spectrum serine protease inhibitor and a specific elastase inhibitor. Cartilage degrading activity was lost on storage which may explain why it has not been widely reported before.

CONCLUSION

Rheumatoid SF can directly degrade cartilage through the action of proteases. There is an involvement of serine proteases, elastase in particular.

Cartilage contribution to gender differences in joint disease progression. A study with rat articular cartilage

OBJECTIVE

Rheumatoid arthritis is associated with a worse prognosis in females and is influenced by sex hormone changes. Similar observations in osteoarthritis support the hypothesis that gender differences in cartilage make a hitherto unrecognized contribution to gender differences in arthritis. The aim of the present study was to investigate potential gender differences in articular cartilage biochemistry, metabolism and response to inflammatory mediators.

METHODS

Femoral head cartilages from age-matched male and female Wistar rats were analysed for the water, glycosaminoglycan, hydroxyproline and collagen crosslink contents. Proteoglycan loss and synthesis were assessed in vitro, and in the presence and absence of serum and interleukin-1. An in vivo model of inflammation-induced cartilage degradation was employed to investigate gender differences in cartilage susceptibility to erosion caused by granulomatous tissue.

RESULTS

Articular cartilage from male Wistar rats presented higher levels of both proteoglycan and collagen and showed a lower spontaneous glycosaminoglycan loss and higher proteoglycan synthesis in vitro than cartilage from females. Proteoglycan synthesis from female, but not male, cartilage was significantly stimulated by foetal calf serum. Female cartilage was more sensitive to IL-1 inhibition of proteoglycan synthesis while the opposite was observed in IL-1-induced proteoglycan loss. Female cartilage was more susceptible to granuloma-induced degradation than male when implanted into female mice, but no differences were observed between male and female cartilage implanted in male mice.

CONCLUSION

These results demonstrate important gender differences in cartilage biochemistry, metabolism and susceptibility to inflammatory mediators which may have important consequences for the joint destruction in arthritis and support a role for hormone therapy.

The influence of sex in arthritis: is cartilage an overlooked factor?

Sex emerges as a predominant risk and prognostic factor from epidemiological studies in a variety of rheumatic diseases. Investigations into the underlying mechanisms stress sex related differences in immune and inflammatory responses. Cartilage destruction is an essential feature of most arthropathies and plays an essential role in the symptomatology and progression of arthritis. Based on published evidence and recent experimental observations, we explore the possibility that sex differences in articular cartilage may be an important, though unrecognized, factor in the effects of sex and related hormones in the progression of articular disease.

Sex differences in inflammation induced cartilage damage in rodents. The influence of sex steroids

OBJECTIVE

To investigate sex differences in granulomatous inflammation and its effects upon articular cartilage and to assess the potential role of sex steroids in the process.

METHODS

The cotton-pellet cartilage implant model was used with male and female mice in the presence and absence of gonadectomy and hormone replacement. The effects of granulomatous tissue upon articular cartilage was assessed and tissue content of interleukin 1 (IL-1) was determined. The expression of sex hormone receptors in inflammatory tissue was investigated by immunocytochemistry.

RESULTS

Female mice showed a higher ability than males to degrade cartilage irrespective of the sex of the cartilage implanted. Gonadectomy resulted in a significant acceleration of cartilage damage in both sexes, which was reverted by estrogen replacement in females and androgen replacement in males. Female granulomata had significantly higher IL-1 content than those from males. Gonadectomy was associated with an increased IL-1 content in males but not in females, the effects being abolished by androgen replacement in males. Estrogen and androgen receptors were identified in inflammatory cells from the granulomatous tissue.

CONCLUSION

Our data demonstrate that sex hormones affect inflammation induced cartilage degradation in male and female mice probably through the modulation of cytokine production and release in the granulomatous tissue. Further investigation on the effects of sex steroids in inflammation induced cartilage degradation may help elucidate their pathogenic role and therapeutic potential in human disease.

Protective effect of androgens against inflammation induced cartilage degradation in male rodents

OBJECTIVES

Rheumatoid arthritis (RA) is a disease which predominantly affects women. Interestingly, low serum androgen levels and clinical improvement with androgen replacement have been reported in male patients. The aetiopathogenic role of sex hormones in arthritis and their potential long term effects on joint destruction and disability remains unclear, however. This study was designed to investigate the potential influence of sex hormones on inflammation induced cartilage degradation in male rodents.

METHODS

An in vivo model of cotton wrapped cartilage implants was used to assess the effects of androgen, oestradiol, and progesterone on inflammation induced cartilage degradation, and in vitro techniques were used to investigate the direct actions on cartilage metabolism and cytokine production in male animals.

RESULTS

Orchidectomy resulted in accelerated cartilage damage which was reversed by replacement of physiological levels of androgens. Granulomatous tissue from castrated male rodents produced higher amounts of interleukin 1. Sex hormones reduced spontaneous proteoglycan loss in vitro but did not interfere with the effects of interleukin 1 on cultured cartilage.

CONCLUSIONS

Androgens appear to protect cartilage from inflammation induced breakdown in male animals. These results support a pathogenic role for hypoandrogenism in rheumatoid arthritis and suggest that long term androgen replacement may help prevent joint damage and disability.

Sex steroids affect glucocorticoid response to chronic inflammation and to interleukin-1

The influence of gender and sex hormones upon both the hypothalamic-pituitary-adrenal (HPA) axis and the immune and inflammatory responses is well recognized, but it is not clear to what extent the two effects are interdependent. We have investigated this interaction using a chronic inflammation model. Corticosterone levels were measured in mature BALB/c male and female mice, which were intact, sham-operated or gonadectomized. No significant differences were found between groups in baseline corticosterone, but systemic inflammation (cotton-induced granulomas) resulted in stimulation of the HPA axis in a reproducible pattern. Corticosterone levels were higher in sham-operated females than in males, but gonadectomy had opposing effects in the two genders, resulting in reduced levels in females but significantly increased levels in males. A similar pattern emerged after stimulation by ether exposure or injection of interleukin-1 beta. In the chronic inflammatory model, replacement of ovariectomized females with physiological levels of progesterone restored a response similar to that of intact females. Physiological levels of 5 alpha-dihydrotestosterone prevented the increase in corticosterone levels caused by castration in males and also resulted in reduced corticosterone levels in sham-operated females. Oestradiol treatment did not affect corticosterone levels. Release of interleukin-1 by peritoneal macrophages from intact and gonadectomized mice with chronic inflammation followed a similar pattern, females releasing more than males. These data suggest a complex inter-relationship between sex steroids, inflammatory stimuli and the HPA axis, such that females have a greater tendency than males to generate activating signals and in addition have a greater sensitivity to such factors.

Visual space perception and visually directed action

The results of two types of experiments are reported. In 1 type, Ss matched depth intervals on the ground plane that appeared equal to frontal intervals at the same distance. The depth intervals had to be made considerably larger than the frontal intervals to appear equal in length, with this physical inequality of equal-appearing intervals increasing with egocentric distance of the intervals (4 m-12 m). In the other type of experiment, Ss viewed targets lying on the ground plane and then, with eyes closed, attempted either to walk directly to their locations or to point continuously toward them while walking along paths that passed off to the side. Performance was quite accurate in both motoric tasks, indicating that the distortion in the mapping from physical to visual space evident in the visual matching task does not manifest itself in the visually open-loop motoric tasks.

Pregnancy and rheumatoid arthritis: an overview

The literature concerning the relationship of rheumatoid arthritis (RA) to pregnancy is reviewed. The amelioration of RA during pregnancy is a complex process. No specific factor that causes amelioration and is amenable to therapeutic intervention has been identified. Either RA is associated with lower fertility/fecundity, or pregnancy induces a protective effect against the development of the disease. The biological mechanism of these findings is not established.

[Spinal cord neuroschistosomiasis: clinical and laboratory evaluation of 5 cases]

Schistosomiasis mansoni is an endemic disease in Brazil. Cases of nervous system schistosomiasis have been referred in our medical literature for the past forty years. In this report five cases of schistosomiasis of the spinal cord are studied. A review of the literature has been made and some clinical, laboratory and therapeutical aspects are discussed.

The role of pregnancy in the course and aetiology of rheumatoid arthritis

The aetiology of rheumatoid arthritis (RA) is unknown, although being female is generally recognized as the most important independent risk factor, the disease being 2 to 3 times more frequent in females than in males. The dramatic effect of pregnancy in rheumatoid arthritis has been documented for over 50 years. This review examines the evidence and possible mechanisms by which pregnancy modifies the disease process and may alter predisposition to the development of RA in later life.

The effects of gender and sex hormones on outcome in rheumatoid arthritis

Disease patterns in RA vary between the sexes; the condition is more commonly seen in women, who exhibit a more aggressive disease and a poorer long-term outcome. Men, however, are more likely than women to die from extra-articular complications of rheumatoid disease. This chapter discusses the outcome and mortality studies that substantiate these conclusions and then examines the possible mechanisms that may account for them, including the HLA system, seropositivity, compliance, response to therapy and pain threshold. In particular, sex and sex hormones emerge as independent risk factors in rheumatoid disease. The epidemiological evidence points towards a peak age of onset of RA at the time of the menopause in women and towards later in life in men. Premenopausal women may fare better than postmenopausal women with RA. The possible protective effects of the oral contraceptive pill and the dramatic amelioration with pregnancy are well documented. In vivo and in vitro studies have demonstrated that sex hormones interfere with a number of the putative processes involved in the pathogenesis of RA, including immunoregulation, interaction with inflammatory mediators and the cytokine system, and direct effects on cartilage itself. All these observations point towards the importance of gonadal hormones. However, trials on the potential therapeutic use of sex hormones in RA are limited and, as yet, disappointing. Further work is necessary to determine whether the roles of sex hormones are as central protagonists or just supporting cast in the complex arena of rheumatoid disease.

Visual space perception and visually directed action

The results of two types of experiments are reported. In 1 type, Ss matched depth intervals on the ground plane that appeared equal to frontal intervals at the same distance. The depth intervals had to be made considerably larger than the frontal intervals to appear equal in length, with this physical inequality of equal-appearing intervals increasing with egocentric distance of the intervals (4 m-12 m). In the other type of experiment, Ss viewed targets lying on the ground plane and then, with eyes closed, attempted either to walk directly to their locations or to point continuously toward them while walking along paths that passed off to the side. Performance was quite accurate in both motoric tasks, indicating that the distortion in the mapping from physical to visual space evident in the visual matching task does not manifest itself in the visually open-loop motoric tasks.

Joint space in radiologically normal knees

Joint space loss is a characteristic feature of rheumatoid arthritis and osteoarthritis. It cannot be fully evaluated, however, without knowledge of the normal variability of joint space size. We have measured joint space size using digital image analysis in a population of radiologically normal individuals. Anteroposterior films of the knee were studied from 685 consecutive patients attending Casualty with unexplained knee pain or following trauma, but with no clinical or radiological evidence of arthritis. Results show that in a radiologically normal population, men have larger joint spaces than women and there is a steady decline in joint space size with age. We found no significant difference in joint space size between weight bearing and non-weight bearing women. There was also no difference in patients presenting with pain and those presenting following an injury. Normal joint space size was not related to height, weight or body mass index in a subgroup of 213 patients. We suggest that patients lose joint space with increasing age and eventually reach a 'pain threshold' at which symptoms of osteoarthritis occur. This explains the increase in joint symptoms in those who begin with smaller joint spaces; that is in women and in the elderly.

[Coronary risk factors in high-rank athletes]

PURPOSE

To report the prevalence of coronary risk factors in elite athletes.

METHODS

The prevalence of coronary risk factors was determined in 88 athletes (62 men and 26 women) who participate representing Brazil, in the Olympic Games at Seul in 1988, in the Project SEUL/COB/AMIL. The risk factors analyzed were: family history of coronary heart disease, hypercholesterolemia (total-cholesterol and subfractions), hypertension, glucose intolerance, smoking and left ventricle hypertrophy (LVH). We compared the mean values of total-cholesterol/HDL-cholesterol between men and women with unpaired Student's t Test. The distribution of risk factors prevalence by sex was analysed with the chi-square test.

RESULTS

Family history of coronary heart disease was detected in 11 (12.5%) athletes. Smoking was found in 12 (13.6%) athletes. There was no one with hypertension or glucose intolerance. LVH was diagnosed with the echocardiogram, in 36 athletes (40.9%). Total-cholesterol mean was 172 +/- 36 mg/dl in men and 187 +/- 34 mg/dl in women. HDL-cholesterol mean was 46 +/- 10 mg/dl in men and 60 +/- 13 mg/dl in women. Total-cholesterol/HDL-cholesterol mean was 4.02 +/- 1.39 mg/dl in men and 3.21 +/- 0.74 mg/dl in women. The difference between total-cholesterol in mean and women was not statistically significant (p less than 0.05). HDL-cholesterol and total-cholesterol/HDL-cholesterol means were statistically different (p less than 0.05). Prevalence distribution of the number of risk factors by sex were not statistically different (p less than 0.05).

CONCLUSION

The results shows how important is to look for coronary risk factors in elite athletes.

Constancy of individual exponents for inspired lung volume: a comment on Harver (1987)

In this paper we made two brief commentaries on Harver's (1987) experiment. The first comment is an observation on the growing area of respiratory psychophysics for which we prefer the name Behavioral Physiology. In the second comment it is suggested that the stable individual differences in the exponent of the psychophysical power law reported by Harver may be an artifact of the psychophysical method employed: category production.

Stability of individual psychophysical functions for perceived distance in natural indoor and outdoor settings

Exp. 1 examined correlations of the power functions exponents for individual observers, for apparent distance in a natural indoor setting, obtained for a group of 9 observers over 5 experimental sessions separated by intersession intervals that varied from 1 day to 9 mo. Stable individual differences in the exponent of the psychophysical power law were shown. Intercorrelations of subjects' exponents were positive and reliable with 1 day between sessions and 9 mo. In Exp. 2 the estimates of apparent distance were made by 5 independent groups of 10 observers each, tested and retested at different intersession intervals. There were 5 intervals of 1 day to 9 mo. Fair temporal stability of psychophysical power function exponents was observed in most groups. In Exp. 3 psychophysical power functions were obtained from magnitude estimates of apparent distance in a natural outdoor setting. The same 10 observers were tested and then retested after 1 day and again after 1 yr. Significant correlations for both intersessions intervals indicated consistent and persisting individual differences. Taken together Exps. 1, 2, and 3, regardless of the environment in which distance estimates were performed, clearly demonstrate that power functions are repeatable, enduring, and characteristic of individuals. In addition, the mean exponents were in reasonable agreement with other reported apparent distance exponents obtained in both settings.

The protective effect of carnitine in human diphtheric myocarditis

Carnitine, an important cofactor in the transport of fatty acids to the interior of cell mitochondria, is depleted in myocardial tissue of guinea pigs submitted to diphtheric toxin administration. Mortality rates were reduced in these animals by supplying exogenous amounts of carnitine. The accumulation of fatty acids in the cytoplasm of human heart cells reported in cases of diphtheria suggests that carnitine might possibly be depleted in human myocardium as well. For the purpose of studying the effect of carnitine administration, 132 diphtheric patients were randomly divided into two groups, one of them (carnitine-treated group, n = 73) receiving DL-carnitine, 100 mg/kg/day during 4 days after admission, in addition to routine treatment, which was prescribed for this and the control group (n = 59). The presence of myocardial damage was evaluated by clinical, electrocardiographic, radiological, and enzymatic criteria. Carnitine administration resulted in decreased incidence of heart failure (P = 0.0475), of pacemaker implants (P = 0.0256), and of lethality indexes due to myocarditis (P = 0.013). We suggest that carnitine can play an important role in the treatment of diphtheric patients.

Scales for measuring subjective distance in children and adults in a large open field

Five age levels (6, 8, 10, 12 years, and adults, N = 127) estimated distance in a large open field by the fractionation method. Scales for subjective distance were derived for each group. It was found that (a) the adults differed from all the other groups, (b) the 12-year-olds differed from the six-year-olds, (c) all the exponents were smaller than 1, (d) perceived distance in a large open field was characterized by underconstancy, and (e) underconstancy was greater for the younger subjects.

Scaling apparent distance in a large open field: some new data

Judged distance in a large open field, scaled by the method of magnitude estimation, is related to physical distance by a power function with an exponent smaller than unity. The exponents obtained with two ranges of distance were not affected by the availability of a standard. The mean exponent for all 80 individual power functions was 0.86, with a standard deviation of 0.11.

Scaling apparent distance in a large open field: presence of a standard does not increase the exponent of the power function

Apparent distance in a large open field was scaled by the method of magnitude estimation with or without a standard distance present. The presence of the standard did not increase the exponent of the power law. The average exponent of the power function relating judged to physical distance was .87. The results are consistent with those of other studies showing that apparent distance is a decelerating function of actual distance in a natural outdoor setting.

Scales for subjective distance in a large open field from the fractionation method: effects of type of judgment and distance range

By means of the method of fractionation, scales for subjective distance were derived from five different types of judgment accomplished with two ranges of distance estimated in a large open field. It was found (a) that the scales for subjective distance are to a considerable extent influenced by ways of obtaining the judgments, (b) that the scales are relatively uninfluenced by range of distance, (c) that the exponents of the scales for egocentric distances are different from those for exocentric distances, (d) that the functions for egocentric distances are slightly decelerated but for exocentric distances slightly accelerated, and (e) that the average exponent for all subjects was 0.98.

[Cryptococcal meningoencephalitis functioning as expansive process. Report of a case]

A case of cryptococcal meningoencephalitis occurrying in a 26-year-old white man disclosing clinical as well radiological features of a expanding process localized in the right cerebral hemisphere is reported. A definitive diagnosis was established through histopathologic examination following right fronto-temporo-parietal exploratory and decompressive craniotomy. Cryptococcus neoformans was easily demonstrated in the leptomeninges as well as in cystic spaces in the brain substance.

[Recurrent meningitis and cerebrospinal fluid fistula in fronto-basal cranio-encephalic trauma. Report of a case]

A case of fronto-basal traumatism with isolated fracture of the left sphenoidal sinus is reported. Meningitis occurred 5, 8 and 11 years, respectively, after injury. Cerebrospinal fluid cranio-nasal fistula was observed at the first time 8 years after injury and remained intermitent in the last 6 years. The surgical technic was accomplished according to the procedure devised by Dietz and consisted of plastics of the anterior floor of the skull accompanied by galeaperiosteal junction taken out from the scalp.

[Familial occurrence of basilar impression]

The authors studied nine members of the same family; two among them received surgical treatment for basilar impression and Arnold-Chiari malformation. In the other members of the family, several signs and symptoms of central nervous disease were observed. All patients had the apex of the odontoid apophysis above McGregor's line, 4 mm in the case 9, and 10 mm or more in the others.

[Decompression craniotomy in acute brain edema. Apropos of 30 operated cases]

Uni or bilateral decompressive craniotomy was carried out in 30 patients bearing severe cerebral edema of etiology predominantly traumatic. Coma, midriasis and decerebrate state were the mostly commonly clinical features presented. The average survival in the series was 46.6%.

Turner-mongolism polysyndrome. Review of the first eight known cases

To date, a total of eight cases of the Turner-mongolism polysyndrome have been recognized. The clinical manifestations included retarded growth (resulting in a small and infantile appearance), with shield-like chest, poorly developed breasts, absent body hair, brachycephaly, short neck with foldings and low hairline, oblique eyes with epicanthal folds, squat nose, scrotal or normal tongue, abnormal hard palate (high or cleft), short hands and feet, frequent cubitis valgus, normal clitoris (may be either hypoplastic or peniform), mental retardation, and the XO/G+ karyotype, mosaic for XO in most instances. At this time, a single cause for all cases of the double aneuploidy is not known.

On the mechanism of hyperkalaemia due to hyperosmotic expansion with saline or mannitol

1. To investigate the mechanism of the hyperkalaemia that results from hyperosmotic infusions of saline or mannitol, nephrectomized dogs received hyperosmotic infusions of sodium chloride or mannitol with various amounts of sodium bicarbonate. Pa,co2 was held constant. Body spaces and mean whole-body intracellular hydrogen ion activity [H+]i were measured with tritiated water, Na36Cl, and [14C]5,5-dimethyl-2,4-oxazolidinedione (DMO).

2. The extracellular hydrogen ion activity after infusion varied, but all animals developed intracellular alkalosis ([H+]i-35 nmol/l, SEM±5, P&lt;0.001). There was no net movement of Na+ across cell membranes. There was a significant negative correlation between the changes in extracellular hydrogen ion and that in extracellular potassium concentrations. A greater apparent cellular penetration of HCO3− resulted in less net loss of K+ from cells (r = 0.69, P &lt; 0.01).

3. The results suggest that the hyperkalaemia secondary to hyperosmolar infusion of saline or mannitol is not due to extracellular acidosis, but cellular dehydration, altered cell metabolism or altered cell-membrane function may contribute to the leak of K+ from cells in these circumstances.

[Choriocarcinoma initially manifesting as a cerebral tumor]

Os autores descrevem um caso de coriocarcinoma cerebral metastático, removido cirurgicamente, ocorrendo numa paciente de 19 anos e localizado na porção posterior do lobo frontal esquerdo. Um estudo retrospectivo da paciente revelou apenas discreta perda sangüínea pelos genitais, iniciada algumas semanas após o delivramento de uma criança normal, ocorrido quatro meses antes. O exame colpocitológico da secreção cérvico-vaginal revelou uma classe V de Papanicolau (positivo para células neoplásicas malignas), tendo ulteriormente a paciente sido submetida à histerectomia total com anexectomia bilateral. Um pequeno tumor de aspecto hemorrágico-necrótico foi encontrado na cavidade uterina, tendo o exame histológico mostrado tratar-se de coriocarcinoma. Os autores tecem considerações clínico-patológicas sobre o coriocarcinoma. com especial referência às lesões metastáticas cerebrais.