Preserved and impaired aspects of predictive grip force control in cerebellar patients.

Objective: To analyze preserved and impaired aspects of feedforward grip force control during cyclic arm movements with a hand-held object after cerebellar damage.

Methods: We tested eight subjects with unilateral or bilateral cerebellar pathologies and eight healthy control subjects. Participants performed cyclic vertical arm movements with a hand held instrumented object at three different speeds.

Manual and hemispheric asymmetries in the execution of actual and pantomimed prehension.

Impairments of the ipsilesional hand after brain damage have been reported in goal-directed motor acts and in pantomimes; the relationship between both movement conditions is largely unknown. In the presented study, pantomimed and actual prehension was examined in 29 stroke patients with left brain damage (LBD) or right brain damage (RBD) as well as in 21 control subjects. Kinematic analyses revealed various performance differences between the conditions of movement execution and the subject groups.

It takes the whole brain to make a cup of coffee: the neuropsychology of naturalistic actions involving technical devices.

Left hemisphere dominance has been established for use of single familiar tools and tool/object pairs, but everyday action in natural environment frequently affords multi-step actions with more or less novel technical devices. One purpose of our study was to find out whether left hemisphere dominance extends to such naturalistic action. Another aim was to analyze the cognitive components contributing to success or failure.

Pantomime of object use: a challenge to cerebral localization of cognitive function.

The paper illustrates difficulties and insecurities of localizing cognitive functions with the example of pantomime of object use. Numerous studies have established a particular sensitivity of this task to left brain damage (LBD), but there is no agreement as to how components of its cognitive architecture are related to the laterality and intrahemispheric location of responsible lesions. Apraxia and asymbolia have been suspected to be crucial for explaining the vulnerability of pantomime to LBD, but analysis of correlations between impairments of pantomime, imitation of gestures, drawing from memory, and language in patients with LBD and aphasia suggests that neither of these putative deficits can adequately account for the data.

The dependence of ipsilesional aiming deficits on task demands, lesioned hemisphere, and apraxia.

Neuroimaging studies as well as neurophysiological and lesion data indicate that the ipsilateral hemisphere plays a role in controlling the active limb. However, the nature and the conditions of this ipsilateral control are not well understood. We measured aiming movements with the ipsilesional limb toward targets with different characteristics which were made by patients with unilateral left brain damage (LBD) or right brain damage (RBD).

Defective pantomime of object use in left brain damage: apraxia or asymbolia?

Disturbance of pantomime of object use in patients with left brain damage (LBD) and aphasia has been firmly established but its nature remains controversial. It may be due to an inability to perform movements from memory without external support by objects (apraxia) or to an inability to produce signs referring to absent objects and actions (asymbolia). The need to perform movements without external support is shared with imitation of gestures, and the demand to designate absent objects with drawing from memory.

Grip force control during object manipulation in cerebral stroke.

Objective: To analyze impairments of manipulative grip force control in patients with chronic cerebral stroke and relate deficits to more elementary aspects of force and grip control.

Methods: Nineteen chronic stroke patients with fine motor deficits after unilateral cerebral lesions were examined when performing 3 manipulative tasks consisting of stationary holding, transport, and vertical cyclic movements of an instrumented object. Technical sensors measured the grip force used to stabilize the object in the hand and the object accelerations, from which the dynamic loads were calculated.

Ipsilesional deficits during fast diadochokinetic hand movements following unilateral brain damage.

Impaired sensorimotor function of the hand ipsilateral to a unilateral brain lesion has been reported in a variety of motor tasks; however, elementary diadochokinetic movements, such as tapping with the index finger, seem to be preserved in chronic-lesion patients. Three different diadochokinetic movements (forearm diadochokinesis, hand tapping (HT) and finger tapping (FT)) were tested in patients with left brain damage (LBD) and right brain damage (RBD) and control subjects. Movements were measured three-dimensionally and the kinematics of joint angles were analyzed.

Imitation and matching of hand and finger postures.

Converging evidence from patients with unilateral brain lesions, from a patient with callosal disconnection, and from functional imaging in healthy subjects suggests different competencies of both hemispheres for imitation and matching of hand and finger postures. Whereas the left hemisphere is fully competent for processing hand postures, an additional right hemisphere contribution is needed for finger postures. I propose that the left hemisphere is responsible for coding gestures with reference to knowledge about the structure of the human body, whereas a right hemisphere contribution is needed for visuospatial exploration and analysis of gestures.

Preanalytical Variables and Their Influence on the Quality of Laboratory Results.

While analytical standards have been developed by established quality control criteria, there has been a paucity in the development of standards for the preanalytical phase. Only recently recommendations have been published regarding the quality of samples including the definition of the optimal sample size, the use of anticoagulants and stabilizers, stability criteria regarding transport and storage and handling of hemolytic, lipemic and icteric samples. Technical recommendations regarding sampling, transport and identification have been developed by national and international consensus organizations.

A telemedical approach to the screening of diabetic retinopathy: digital fundus photography.

Objective: The importance of screening for diabetic retinopathy has been established, but the best method for screening has not yet been determined. We report on a trial of assessment of digital photographs by telemedicine compared with standard retinal photographs of the same fields and clinical examination by ophthalmologists.

Research Design And Methods: A total of 129 diabetic inpatients were screened for diabetic retinopathy by slit-lamp biomicroscopy performed by an ophthalmologist and by two-field 50 degrees non-stereo digital fundus photographs assessed by six screening centers that received the images by electronic mail.

Preanalytical factors and their influence on analytical quality specifications.

Whereas analytical standards are described by established quality control criteria, no such standards exist for defining the quality of the preanalytical phase. A working group of the German Society for Clinical Chemistry and Laboratory Medicine has defined recommendations to describe the quality criteria for materials and processes used in the diagnostic process between patients and the analytical step. Thus, the quality of the sample may be defined regarding its adequacy and amount, as well as anticoagulants and stabilizers used.

Basal forebrain amnesia: does the nucleus accumbens contribute to human memory?

Objective: To analyse amnesia caused by basal forebrain lesions.

Methods: A single case study of a patient with amnesia after bleeding into the anterior portion of the left basal ganglia. Neuropsychological examination included tests of attention, executive function, working memory, recall, and recognition of verbal and non-verbal material, and recall from remote semantic and autobiographical memory.

Matching and imitation of hand and finger postures in patients with damage in the left or right hemispheres.

To disentangle perceptual, conceptual and motor aspects of imitation of gestures, reproduction of meaningless postures of either the hand or the fingers was examined in two conditions. In the matching test a target gesture had to be identified among an array of four gestures performed by different persons and seen under different angles of views. For imitation, the same gestures had to be imitated.

The more you know the less you can tell: inhibitory effects of visuo-semantic activation on modality specific visual misnaming.

WH, a 77-years old right-handed psychoanalyst, displayed modality specific visual misnaming as a sequel of an embolic stroke in the left posterior cerebral artery. WH's errors in visual object naming consisted mainly of semantic paraphasias and perseverations. His verbalizations during testing sometimes manifested a conflict between correct responses and perseverations.

Determination of lamotrigine, carbamazepine and carbamazepine epoxide in human serum by gas chromatography mass spectrometry.

A method for the identification and quantification of the antiepileptics lamotrigine, carbamazepine and carbamazepine epoxide (active metabolite) in human serum is described. In refractory epilepsy the combination of carbamazepine and lamotrigine was recently developed to a modern therapeutic concept. The goal of this paper is therapeutic drug monitoring (TDM) of these substances.

Head and trunk orientation modulate visual neglect.

Five patients with left visual neglect after right hemisphere lesions were examined with a line bisection and a reading task under five different conditions: head and trunk straight ahead, head or trunk oriented 20 degrees to the left and head or trunk oriented 20 degrees to the right. Fixation was always straight ahead. Five patients with right hemisphere lesions but without neglect and five normal subjects served as controls.

Site-specific regulation of organic osmolytes along the rat nephron.

The regulation of organic osmolytes was investigated in acute furosemide and chronic lithium diuresis along the nephron and in urinary bladder of rats. Sorbitol, myo-inositol, glycerophosphorylcholine, and betaine were measured enzymatically or by high performance liquid chromatography in homogenates and bioluminometrically in microdissected tubules. In untreated rats, all osmolytes except myo-inositol increased along the corticopapillary axis.

Determination of choline dehydrogenase activity along the rat nephron.

A radioenzymatic microassay was developed to quantitate choline dehydrogenase activity in single microdissected nephron segments. This enzyme is the rate limiting step in the biosynthesis of betaine, which serves as an intracellular osmoregulatory organic solute in mammalian kidney. The enzyme localized in renal mitochondrial inner membrane forms betaine aldehyde, which in the assay is converted to betaine by oxidative treatment.

Beneficial clinical effect of very early enalapril treatment in patients with acute left ventricular failure complicating myocardial infarction.

Acute myocardial infarction (AMI) leads to left ventricular dysfunction, the extent of which predicts mortality. We studied the effect of very early enalapril treatment in patients with left ventricular failure (Killip classification II-III) resulting from AMI. In a double-blind randomized trial, patients on conventional treatment were started on placebo (PL, n = 15) or 2.

Phospholipase A activity in Pseudomonas aeruginosa.

Our study describes the production, purification and properties of an enzyme from Pseudomonas aeruginosa displaying the properties of phospholipase A. Maximal amounts of enzyme could be detected in the culture supernatant when the bacterium was grown for 3 to 5 days at 37 degrees C in stirred flask cultures containing brain heart infusion. The enzyme was purified by polyethylenimine precipitation and ammonium sulfate precipitation followed by gel filtration.

Effect of decaffeination of coffee or tea on gastro-oesophageal reflux.

Background: Coffee and tea are believed to cause gastro-oesophageal reflux; however, the effects of these beverages and of their major component, caffeine, have not been quantified. The aim of this study was to evaluate gastro-oesophageal reflux induced by coffee and tea before and after a decaffeination process, and to compare it with water and water-containing caffeine.

Methods: Three-hour ambulatory pH-metry was performed on 16 healthy volunteers, who received 300 ml of (i) regular coffee, decaffeinated coffee or tap water (n = 16), (ii) normal tea, decaffeinated tea, tap water, or coffee adapted to normal tea in caffeine concentration (n = 6), and (iii) caffeine-free and caffeine-containing water (n = 8) together with a standardized breakfast.