A patient with Wegener''s granulomatosis presenting with a subarachnoid hemorrhage: case report and review of CNS disease associated with Wegener''s granulomatosis

1. Travellers to high altitude often complain of paroxysmal cough, which has not been previously investigated. We recorded overnight cough frequency and cough-receptor sensitivity to inhaled citric acid in a group of climbers travelling to 5300 m or higher. 2. Cough frequency, monitored in ten subjects, increased from a median of 0 coughs at sea level (range 0-1) to 5 coughs at 5000 m (range 0-13) and to over 60 coughs in subjects ascending to 7000 m. Citric acid cough threshold, measured in 42 subjects, was unchanged on arrival at 5300 m compared with sea level (geometric mean difference 1.26, 95% confidence intervals 0.84-1.89, P = 0.25), but was significantly reduced after 6 days, or more, at altitude compared with sea level (geometric mean difference 2.2, 95% confidence intervals 1.54-3.15, P = 0.0002). Cough threshold was not related to symptoms of acute mountain sickness, oxygen saturation, carbon dioxide tension or lung function. 3. These results indicate an increase in cough and cough-receptor sensitivity after some days at altitude. This may be due to respiratory tract damage from breathing cold dry air at increased ventilatory rates. Other explanations, such as sub-clinical pulmonary oedema or an effect on the cough centre of acclimatization to altitude, cannot be excluded.     

The measurement of the lateralization of narrow bands of noise using an acoustic pointing paradigm: the effect of sound-pressure level

The effects of varying interaural time delay (ITD) and interaural intensity difference (IID) were measured in normal-hearing subjects as a function of eleven frequencies and at sound-pressure levels (SPL) from 60 to 90 dB SPL and at 25-dB sensation level. Using an "acoustic" pointing paradigm, the IID of a 500-Hz narrow-band (100 Hz) noise (the "pointer") was varied by the subject to coincide with that of a "target" ITD stimulus. ITDs of 0, +/- 200, and +/- 400 microseconds were obtained through total waveform delays of narrow-band noise (NBN), including envelope and fine structure. The results of this experiment confirm the traditional view of binaural hearing for like stimuli: There is little perceived displacement away from 0 IID at frequencies of 1250 Hz and above. In the low frequencies, subjects required IIDs greater than the expected 10 dB to perceive a fully lateralized image, and they varied in the maximum value of IID that they required, regardless of frequency. Our subjects did not always perceive the intracranial locations of ITD targets symmetrically: When the signal was delayed to one ear, the resultant matching IID was often different in magnitude than for the same ITD target delayed to the opposite ear for the identical frequency. The results of two subjects suggested that people with asymmetric normal hearing have adapted to their asymmetry for lateralization tasks: The subjects were found to lateralize toward the ear with the greater SPL stimulus, regardless of the ear to which the signal was delayed, when signals of equal SL were presented, and toward the leading ear when signals of equal SPL were presented (unequal SL). Increasing the presentation levels above 60 dB SPL had an effect on the perception of high-frequency ITD targets: As the intensity level increased, the slopes of the IID versus ITD functions increased indicating better discrimination of ITD. This study is in agreement with other studies in providing strong evidence of individual differences in lateralization experiments. These individual differences might be attributable to differential sensitivity to ambiguous time stimulus cues, differential task sensitivity, age effects, threshold asymmetries, or criterion variability.     

Chromatin structure and the expression of cardiac genes

Three experiments investigated visual search for singleton feature targets. The critical dimension on which the target differed from the nontargets was either known in advance or unknown--that is, the critical difference varied either within a dimension or across dimensions. Previous work (Treisman, 1988) had shown that, while the search reaction time (RT) functions were flat in both conditions, there was an intercept cost for the cross-dimension condition. Experiment 1 examined whether this cost would disappear when responses could be based on the detection of any (target-nontarget) difference in the display (by requiring a "heterogeneity/homogeneity" decision). The cost remained. This argues that pop-out requires (or involves) knowledge of the particular dimension in which an odd-one-out target differs from the nontargets; furthermore, that knowledge is acquired through the elimination of dimensions not containing a target. In Experiment 2, the subjects had to eliminate (or ignore) one potential source of difference in order to give a positive response (displays could contain a "noncritical" difference requiring a negative response). The result was a comparatively large cost in the within-dimension (positive) condition. This can be taken to indicate that pop-out as such does not make available information as to the particular feature value in which the target differs from the nontargets. Experiment 3 examined whether search priorities can be biased in accordance with advance knowledge of the likely source of difference. The subjects were found to have a high degree of top-down control over what particular dimension to assign priority of checking to. The implication of the results for models of visual search and selection are discussed.     

Communication in Statistical Terms.

Comments that a number of mostly favorable comments, have greeted the suggestion to substitute "stability" for "significance" in statistical tests (Amer. Psychologist, 1954, 9, 158). One critic inquires at what level a difference is to be called stable. The answer is, at the same level as "significant," i.e., depending upon the rigor called for by the situation. My proposal does not pretend to add anything at all to statistics; it is purely a plea for better communication. One must still define his limits: "stable at the 1% level." Something, however, should be done about the phrase, "at the X% level." Whether one speaks of stability or significance, something is wrong when "at the 1% level" is more of the thing qualified than "at the 5% level." Moreover, "level," whether of significance or stability, does not suggest the real meaning. What we need is a term suggesting frequency of occurrence. Would it be too dangerous to say "stable at 95% probability?" (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phenotypic and genotypic characterization of oral yeasts from Finland and the United States

A total of 4-22 isolates of oral yeasts per subjects from 48 yeast-positive Finnish and American subjects (25 females and 23 males) were phenotyped and genotyped to determine the frequency of simultaneous oral carriage of multiple yeast taxa. An oral sample from either periodontal pockets, oral mucosa or saliva was obtained. All subjects yielded Candida albicans and 3 subjects an additional yeast species (Candida krusei, Candida glabrata or Saccharomyces cerevisiae). The API 20C Aux kit distinguished 9 different carbohydrate assimilation profiles among the C. albicans isolates. Thirty-eight of 46 C. albicans biotype I isolates were categorized in a single numerical profile. PCR analysis, using a random primer OPA-03 and a repetitive primer (GACA)4, detected 2 major genotypic groups among the C. albicans isolates; 44 subjects showing isolates with a "typical" PCR-profile and 4 subjects isolates with an "atypical" PCR-profile. The "atypical" PCR-profile was similar to that of Candida dubliniensis. All C. albicans isolates assimilated xylose, except 5, including the 4 with an "atypical" PCR-profile. No difference was found in distribution of oral yeast species, and of C. albicans phenotypes and genotypes between Finnish and American subjects. The present PCR method may offer a rapid and easy means of distinguishing oral Candida species.     

Rhinotillexomania: psychiatric disorder or habit?

BACKGROUND: Conditions once considered bad habits are now recognized as psychiatric disorders (trichotillomania, onychopagia). We hypothesized that nose picking is another such "habit," a common benign practice in most adults but a time-consuming, socially compromising, or physically harmful condition (rhinotillexomania) in some. METHODS: We developed the Rhinotillexomania Questionnaire, mailed it to 1000 randomly selected adult residents of Dane County, Wisconsin, and requested anonymous responses. The returned questionnaires were analyzed according to age, sex, marital status, living arrangement, and educational level. Nose picking was characterized according to time involved, level of distress, location, attitudes toward self and others regarding the practice, technique, methods of disposal, reasons, complications, and associated habits and psychiatric disorders. RESULTS: Two hundred fifty-four subjects responded. Ninety-one percent were current nose pickers although only 75% felt "almost everyone does it"; 1.2% picked at least every hour. For 2 subjects (0.8%), nose picking caused moderate to marked interferences with daily functioning. Two subjects spent between 15 and 30 minutes and 1 over 2 hours a day picking their nose. For 2 others, perforation of the nasal septum was a complication. Associated "habits" included picking cuticles (25%), picking at skin (20%), biting fingernails (18%), and pulling out hair (6%). CONCLUSION: This first population survey of nose picking suggests that it is an almost universal practice in adults but one that should not be considered pathologic for most. For some, however, the condition may meet criteria for a disorder-rhinotillexomania.     

Pioneer in public health education: Roscoe Conkling Brown

In order to study the influence of ageing on the hormonal function of the endothelium in man, plasma endothelin levels were measured in 11 normal young persons (mean aged 25.7 +/- 1.8 years) and in 16 apparently healthy elderly subjects (mean 87.5 +/- 5.4 years) without anamnestic or clinical signs of symptomatic atherosclerosis. The mean plasma level +/- SD of endothelin was 2.72 +/- 0.61 pg/ml in elderly subjects and 2.09 +/- 0.66 in young subjects. The difference was statistically significant (p < 0.05). Various humoral or local age-related environmental factors may be responsible for this result. In particular increased vascular production of endothelin may be the response to endothelial cell damage caused by an asymptomatic atherosclerotic process. Studies still need to define whether enhanced plasma endothelin levels in elderly subjects not suffering from symptomatic atherosclerosis are the consequence of ageing alone or an ongoing but clinically silent atherosclerotic process.     

Thrombotic complications in essential thrombocythemia with relatively low platelet counts

The purpose of this prospective study was to determine the overall incidence and distribution of lumbo-sacral degenerative changes (i.e. disc protrusion or extrusion, facet degeneration, disc degeneration, nerve root canal stenosis and spinal stenosis) in patients with and without a lumbo-sacral transitional vertebra (LSTV). The study population consisted of 350 sequential patients with low back pain and/or sciatica, referred for medical imaging. In all cases CT scans of the lumbo-sacral region were obtained. In 53 subjects (15%) and LSTV was found. There was no difference in overall incidence of degenerative spine changes between the two groups. We did find, however, a different distribution pattern of degenerative changes between patients with and those without an LSTV. Disc protrusion and/or extrusion occurred more often at the level suprajacent to the LSTV than at the same level in patients without LSTV (45.3% vs 30.3%). This was also the case for disc degeneration (52.8% vs 28%), facet degeneration (60.4% vs 42.6%) and nerve root canal stenosis (52.8% vs 27.9%). For spinal canal stenosis there was no statistically significant difference between the two categories. In conclusion, our findings indicate that an LSTV does not in itself constitute a risk factor for degenerative spine changes, but when degeneration occurs, it is more likely to be found at the disc level above the LSTV.     

Trend of circulating eosinophils in healthy children and children suffering from infectious diseases. A retrospective study

INTRODUCTION: Acute bacterial and viral infections are accompanied by a marked diminution in circulating eosinophils in the blood. This forms part of the host's physiological response to acute infection and was first studied in adults early this century. The aims of this study were to check whether eosinopenia during acute phlogosis is a phenomenon present in pediatric patients, and whether the trend is comparable to the experimental models reported; to describe the trend of circulating eosinophils in the remission process. METHODS: A retrospective study was performed in 34 children hospitalised in the Pediatric Hospital of AUSL 2-Lucca (Italy) for bacterial or viral infective diseases documented by cell culture or presumed diagnosed. Children with the following characteristics were excluded from the study: 1) blood samples collected for hemochrome analysis at times other than normal (7-8 a.m.); 2) cortisone treatment administered up to 5 days prior to blood sample and/or during hospitalisation; 3) positive personal anamnesis for manifest allergic diseases. On admittance (children during acute phase) and at the start of remission, an absolute count of circulating eosinophils was performed in these children using an automatic globule counter. Sixty-six children with non evident infective and/or inflammatory diseases were included in the study as a control group. This group was also selected in the same way as infective subjects. RESULTS: The mean number of circulating eosinophils was 288 (+/- 248) in the control group, 46 (+/- 58) in subjects at the acute phase of infective pathology and 252 (+/- 162) in infective patient during the remission phase. The difference between the two means was statistically significant. This characteristic falling and rising trend of circulating eosinophils was found in 33 of the 34 infective subjects examined. CONCLUSIONS: Eosinophil values found in control subjects are broadly in line with those reported in the literature. Eosinopenia during the course of acute infection and the early rise during remission represent a characteristic phenomenon indicating the body's "normal" response to a non-parasitic infection. Both eosinophil levels, namely in the control group (288/mm3) and in acute-phase subjects (46/mm3), should be regarded as "normal" provided they refer to the appropriate situation. The precocity and precision with which the eosinophil trend follows the phases of the infection underlines the value of the assay of these cells as a reliable parameter for monitoring acute infection. There are also indications that, in an inflammatory situation, the behaviour of circulating eosinophils may provide a practical clinical marker of the predominant lymphocyte pattern (Th1 or Th2), as well as the phase of phlogosis, active or remission.     

Antibodies to prothrombin imply a risk of myocardial infarction in middle-aged men

Antiphospholipid antibodies in patients with "antiphospholipid syndrome" may be directed at least in part against plasma phospholipid-binding proteins, such as beta 2-glycoprotein I or prothrombin, which are involved in the control of thrombosis and haemostasis. IgG-class antibodies against prothrombin and beta 2-glycoprotein I were measured by enzyme-linked immunoassay in initially healthy middle-aged dyslipidaemic men (non-high-density lipoprotein > 5.2 mml/l). Serum samples had been drawn at entry to a 5-year coronary primary-prevention trial with gemfibrozil from 106 subjects who experienced either a non-fatal myocardial infarction or cardiac death during the follow-up and from 106 subjects without coronary episodes, matched for treatment group (gemfibrozil/placebo) and geographical area. The antiprothrombin antibody level, as expressed in optical density units, was significantly higher in patients than in controls (0.26 +/- 0.17 versus 0.22 +/- 0.09; p < 0.02). A high level of antiprothrombin antibodies (highest tertile of distribution) predicted a 2.5-fold increase in the risk (95% confidence interval 1.2-5.3) of myocardial infarction or cardiac death. The distribution of IgG-class antibodies against beta 2-glycoprotein I did not differ significantly between cases and controls. The joint effect of antiprothrombin antibodies and other factors associated with hypercoagulative state: triglyceride level, lipoprotein(a) and smoking, was multiplicative for the risk. Antiprothrombin antibodies are a new immunological predictor of myocardial infarction and the effect of these antibodies may be mediated by hypercoagulative mechanisms.     

Urinary total isothiocyanate (ITC) in a population-based sample of middle-aged and older Chinese in Singapore: relationship with dietary total ITC and glutathione S-transferase M1/T1/P1 genotypes

Isothiocyanates (ITCs), degradation products of glucosinolates (which occur naturally in a variety of cruciferous vegetables), have been shown to exhibit chemopreventive activity. These compounds are metabolized in vivo to form the corresponding dithiocarbamates, which are the major urinary metabolites of ITCs, by a pathway involving the glutathione S-transferase (GST) class of enzymes. Using a newly developed assay that measures total ITC (primarily ITC conjugates) in urine, we examined the relationships between cruciferous vegetable intake (obtained from a food frequency/portion size questionnaire administered in person); dietary total ITC level; GSTM1, GSTT1, and GSTP1 genotypes; and levels of total ITC in spot urine samples collected from 246 Singapore Chinese (111 men and 135 women), ages 45-74 years, who are participants of the Singapore Cohort Study on diet and cancer. Consumption level of cruciferous vegetables was high in study subjects (mean consumption = 345 times per year, mean daily intake = 40.6 g), which was >3 times the comparable level of intake in the United States. Mean daily intake of total ITC among study subjects was 9.1 micromol, and there was a 2.5-fold difference between the 25th and 75th percentile values. Seventy-three % of study subjects tested positive for ITC in urine, and there was a 4-fold difference between the 25th and 75th percentile values among the positive subjects. There was a highly significant positive association between dietary intake and urinary excretion levels of total ITC (two-sided P = 0.0003) that was stronger than the association between overall cruciferous vegetable intake and urinary ITC level, which also was statistically significant (P = 0.0004). There was no difference in urinary ITC levels between GSTM1-null and GSTM1-positive study subjects (P = 0.61) or between subjects with differing GSTP1 genotypes (P = 0.77), but urinary excretion of ITC was significantly higher among GSTT1-positive subjects, relative to GSTT1-null subjects (P = 0.006). The strength of the association between GSTT1 genotype and urinary total ITC level was highly dependent on the level of cruciferous vegetable consumption (or dietary ITC level) in study subjects. Among subjects in the lowest tertile of cruciferous vegetable intake, there was little evidence of an association between GSTT1 genotype and urinary total ITC level (P = 0.67). In contrast, there was a strong and statistically significant association between GSTT1 genotype and urinary total ITC among subjects in the highest tertile of cruciferous vegetable intake (P = 0.02), whereas those in the middle tertile of cruciferous vegetable consumption exhibited an association of intermediate strength (P = 0.04). These results suggest the presence of GSTT1 inducers in cruciferous vegetables.     

Hyperhomocyst(e)inemia and a common methylenetetrahydrofolate reductase mutation (Ala223Val MTHFR) in patients with inherited thrombophilic coagulation defects

To assess whether certain abnormalities of the sulfated amino acid metabolism are associated with the occurrence of thromboembolic events in patients with inherited thrombophilic conditions, the levels of homocyst(e)ine, before or after methionine load, and the presence of the Ala223Val substitution in the 5,10-methylenetetrahydrofolate reductase (MTHFR) were evaluated in 119 subjects with a congenital single thrombophilic condition (type I deficiency of antithrombin n = 10, protein C n = 24, protein S n = 16; activated protein C resistance due to factor V Leiden mutation n = 69). Sixty-three subjects had experienced at least one documented thrombotic event, while the remaining 56 subjects were still free from any thrombotic symptom. Our results show that (1) high homocyst(e)ine levels, either in fasting condition or after methionine load, were not more frequent in subjects with inherited thrombophilic alterations (14.4%) than in normal control subjects (10% by definition) and (2) the frequency of hyperhomocyst(e)inemia was similar in thrombophilic subjects, who already have (14.3%) or have not (14.6%) experienced thrombotic events. As regards the MTHFR mutation, the homozygous condition was present in 23.2% of the thrombophilic patients versus 17.5% in the control subjects, a nonsignificant difference. The mutation was slightly more frequent in those thrombophilic subjects who had suffered a thrombotic episode (25.5%) versus those with no thrombosis (20.8%), with odds ratios of 1.61 (confidence interval (CI) = 0.58-4.52) and 1.24 (CI = 0.42-3.43), respectively. These differences were also nonsignificant. It is concluded that in subjects with inherited thrombophilias, a condition of hyperhomocyst(e)inemia "per se" is not a factor increasing the risk of thrombosis. The risk enhancement conferred by the MTHFR mutation, if any, seems to be slight or limited, and its significance could be ascertained only in a large multicenter trial.     

Do humans ape? Or do apes human? Imitation and intention in humans (Homo sapiens) and other animals.

A. Whiten, D. M. Custance, J.-C. Gomez, P. Teixidor, and K. A. Bard (1996) tested chimpanzees' (Pan troglodytes) and human children's (Homo sapiens) skills at imitation with a 2-action test on an "artificial fruit." Chimpanzees imitated to a restricted degree; children were more thoroughly imitative. Such results prompted some to assert that the difference in imitation indicates a difference in the subjects' understanding of the intentions of the demonstrator (M. Tomasello, 1996). In this experiment, 37 adult human subjects were tested with the artificial fruit. Far from being perfect imitators, the adults were less imitative than the children. These results cast doubt on the inference from imitative performance to an ability to understand others' intentions. The results also demonstrate how any test of imitation requires a control group and attention to the level of behavioral analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorizing objects in isolation and in scenes: What a superordinate is good for.

Many studies have shown that subjects are faster at categorizing objects into "basic" concepts than into more general superordinate concepts. However, all of these studies have used a categorization task in which single, isolated objects are identified. There is good reason to believe that superordinate concepts are typically used to refer to collections of objects rather than to individual objects. For example, people more often use the term furniture to refer to a number of pieces of furniture rather than to name a single piece. This suggests that superordinate concepts include information about multiple objects and their common relations, particularly the typical scenes in which such objects appear. Four experiments examined this possibility by investigating whether the basic concept advantage will decrease or reverse itself when subjects are asked to categorize an object as part of a scene. The results showed that the basic-superordinate difference did decrease when subjects categorized objects in scenes. Furthermore, when an object was placed in an inappropriate scene, there was more interference for superordinate identifications. The results suggest qualitative differences in the representations of superordinate and basic concepts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The time-course of analytic psychotherapy: A semiotic phenomenonology.

The distinctness and linear order of "beginning" and "termination" in analytic psychotherapy is questioned by examining therapy as a process of multiple transitions between experience and hermeneutic representation. It is argued that critical points (CPs) such as beginning and termination may be established at the level of experience, but must be rendered relative at the level of representation, to allow the therapeutic discourse semiotic freedoms essential for its development. This approach subjects CPs to a "middleness principle", whereby all phases of therapy must be analyzed according to the way they connect to preceding and subsequent experience. Such analysis is afforded by redefining CPs according to the way they shape the therapeutic discourse, which is illustrated in fragments of therapeutic conversation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of the relationship between low back pain and lumbar posteroanterior stiffness

OBJECTIVE: To investigate the relationship between low back pain (LBP) and lumbar posteroanterior (PA) stiffness. DESIGN: A repeated-measures design was used to measure lumbar posteroanterior stiffness on two occasions in subjects with and without LBP. SUBJECTS: Twenty-five subjects with acute or subacute LBP and twenty-five pain-free subjects participated. Pain subjects reported pain on the application of a manual PA force to the lumbar spine and had no contraindication to PA stiffness testing. Pain-free subjects reported no history of LBP requiring treatment, and obtained a score of 0 on the McGill Pain Questionnaire. METHODS: PA stiffness was measured in subjects with LBP when (a) they first presented with pain and (b) when pain had resolved by more than 80%. Pain-free subjects, matched with pain subjects on gender, age, vertebral level to be tested and time between tests, were also measured on two occasions, to control for the effects of repeated stiffness testing and the passing of time. RESULTS: In subjects with low back pain stiffness decreased by 1.21 N/mm between test 1 and test 2. A paired t test found a significant difference between the tests (t = 3.04, df = 24, p = .006). In subjects without pain, there was an increase in stiffness of 0.74 N/mm between test 1 and test 2; a paired t test found no significant difference between the tests (t = -1.673, df = 24, p = .107). CONCLUSIONS: Subjects with LBP showed increased PA stiffness compared with when they had little or no pain, whereas pain-free subjects showed unchanged PA stiffness over time.     

Active detection of chronic obstructive pulmonary disease and asthma in the general population. Results and economic consequences of the DIMCA program

The aim of this prospective study was to detect subjects in the general population with objective signs of chronic obstructive pulmonary disease (COPD) or asthma at an early stage. This was done by means of a two-stage protocol involving screening and a subsequent 2-yr monitoring of all subjects with positive results of screening. The study was done in 10 general practices located in the eastern part of the Netherlands. A random sample was taken from the general population aged 25 to 70 yr. All known COPD and asthma patients were excluded. A total of 1,749 subjects met the inclusion criteria: 1,155 subjects (66%) agreed to participate in the screening stage of the study. A total of 604 subjects (52.3%) showed symptoms or objective signs of COPD or asthma during the screening and were considered "positive." Of those with positive screening results, 384 subjects (64%) agreed to participate in the second, 2-yr monitoring stage of the study. The costs involved in detection were calculated for three different scenarios, as follows: (1) The detection of subjects with persistently decreased lung function or an increased level of bronchial hyperresponsiveness (BHR) during 6 mo of monitoring; (2) Scenario 1 plus the detection of subjects with a rapid decline in lung function with signs of BHR during 12 mo of monitoring; (3) Scenario 2 plus the detection of subjects with a moderate increase in the decline in lung function or signs of BHR during 24 mo of monitoring. The costs of lung function assessments, organization, transportation, and patient time were included. The costs were converted to United States dollars on the basis of purchasing power (1 United States dollar = 2.08 Netherlands guilders). During the second stage, 252 subjects were detected with objective signs of COPD or asthma at an early stage. Smoking status as a screening criterion was neither sensitive nor specific. Because there was no evidence of biased recruitment or selection during the program, the proportions of subjects found to have objective signs of COPD or asthma at an early stage could be extrapolated to the general population. Of the general population, 7.7% showed persistently reduced lung function or increased BHR. Another 12.5 % of the general population showed a rapid decline in lung function (> 80 ml/yr) in combination with signs of BHR, and a further 19.4% of the general population showed mild objective signs of COPD or asthma. The average costs per detected case varied from US$953 (Scenario 1) to US$469 (Scenario 3). In conclusion, detection of COPD or asthma at an early stage by means of a two-stage protocol was feasible at relatively little expense in comparison with other mass screening programs. Persistently decreased lung function or a rapid decline in lung function (Scenario 2) was observed in approximately 20% of the general adult population.     

Visual "closed-loop" and "open-loop" characteristics of voluntary movement in patients with Parkinsonism and intention tremor

Normal voluntary movements are considered to be of two kinds, or to involve two components, (i) a ballistic or "open-loop" type, which are preprogrammed and executed without reference to current sensory information and (ii) a corrective or "closed-loop" type, whose course or termination are regulated by such information. In a previous paper it was suggested that Parkinsonism disrupted the first kind of movement, but intention tremor did not. In the present paper three experiments designed to test this hypothesis are described. Subjects were tested on an acquisition-tracking task using an oscilloscope display and joystick control, and measurements were made of the duration, velocity and error of their initial movements to acquire the target. Parkinsonian movements were found to be considerably different from normal in that (a) most movements by this group lasted longer than the reaction time for their initiation, as if including some secondary correction in their execution, (b) the rate of movement was not varied for different amplitudes (so keeping the duration fairly constant) as in normal subjects, but rather movements of all amplitudes were made at a constant slow rate, so that duration increased markedly with the larger steps, (c) error increased disproportionately as the velocity of movement increased; in particular any movements completed in one reaction time or less tended to be wildly inaccurate, (d) removing either the target or the response marker from the screen at the beginning of a movement had a significant effect, making it shorter in duration and smaller in amplitude than those usually produced with both markers visible all the time. Parkinsonian subjects showed no improvement in performance with repeated attempts at one movement over a whole sequence, so their deficit appears to be stable even after practice on a known fixed task. These results are interpreted as supporting the hypothesis that Parkinsonism interferes with the generation of accurate ballistic action which are characteristic of normal skilled movement. Tremor subjects in general resembled normal control subjects in their initial acquistion movements, but their accuracy was less with the larger steps.     

Mechanism of block by 4-aminopyridine of the transient outward current in rat ventricular cardiomyocytes

Binocular information has been shown to be important for the programming and control of reaching and grasping. But even without binocular vision, people are still able to reach out and pick up objects accurately - albeit less efficiently. As part of a continuing investigation into the role that monocular cues play in visuomotor control, we examined whether or not subjects could use retinal motion information, derived from movements of the head, to help program and control reaching and grasping movements when binocular vision is denied. Subjects reached out in the dark to an illuminated sphere presented at eye-level, under both monocular and binocular viewing conditions with their head either free to move or restrained. When subjects viewed the display monocularly, they showed fewer on-line corrections when they were allowed to move their head. No such difference in performance was seen when subjects were allowed a full binocular view. This study, combined with previous work with neurological patients, confirms that the visuomotor system "prefers" to use binocular vision but, when this information is not available, can fall back on other monocular depth cues, such as information produced by motion of the object (and the scene) on the retina, to help program and control manual prehension.     

Study of circulating 25 hydroxyvitamin D

The levels of circulating 25 OH-D were determined by a direct radio-competition methods both in normal subjects and in subjects with various pathological conditions. In normal subjects, the average level of 25 OH-D was higher in summer (42.3 ng/ml) than in winter (29.1 ng/ml), P less than 0.005. Monthly variations in the 25 HO-D levels were found in relation to insolation The level of 25 OH-D was practically normal in osteoporosis (28.9 ng/ml), clearly lower in the mixed forms called "osteoporomalacia" (13.5 ng/ml, P less than 0.005) and very low in osteomalacia (5.8 ng/ml, P less than 0.001). In cases of cortisone osteopathy the average level was 22.8 ng/ml (NS). The level of 25 OH-D was also found to be lower in hepatic cirrhosis (11.7 ng/ml, P less than 0.01), in subjects treated with anticonvulsants (P less than 0.01), and in the course of hyperparathyroidism (P less than 0.002). There was no corelation between the level of 25 OH-D and calcaemia, phosphoraemia, circulating immunoreactive parathyroid hormone, or the relative osteoid volume. In contrast, there seemed to be a good correlation with the level of alkaline phosphatasaemia. The level of 25 OH-D was also determined in 4 subjects with vitamin-resistant osteomalacia: in 3 cases hepatic hydroxylation seemed normal, indicating the possibility of a subsequent disorder of vitamin D metabolism; in one case the absence of hepatic hydroxylation was noted.