Construct validity of concepts of attention in healthy controls and patients with CHI.

The present study aimed to examine the construct validity of three aspects of attention, namely focused, divided, and supervisory control of attention. Factor-analytic techniques were applied to scores of healthy subjects on a series of neuropsychological tests tapping these aspects of attention. The two components found did not match the hypothesized aspects and were labeled as Memory-driven Action and Stimulus-driven Reaction.

Executive functioning, attention and frontal lesions in patients with chronic CHI.

To study the presence and nature of dysexecutive problems after CHI, a series of unstructured tasks tapping executive functioning were selected. These were administered to a group of 51 participants with CHI in the chronic stage (i.e.

Recovery versus retest effects in attention after closed head injury.

Recovery in 60 patients with a closed-head injury (CHI) in the first year posttrauma was assessed repeatedly with a series of attention tests. A matched group of healthy subjects was tested at the same intervals to allow us to control for practice effects. The results of a multilevel analysis for longitudinal data show retest effects in all but one of the tests.

Exogenous norepinephrine induces an enhanced microproteinuric response in microalbuminuric insulin-dependent diabetes mellitus.

Exogenous norepinephrine (NE) increases intraglomerular pressure in animal experiments, but it is unknown whether NE induces a microproteinuric response in humans. Moreover, it has not been studied whether possible microproteinuric and renal hemodynamic changes induced by NE are altered in insulin-dependent diabetes mellitus (IDDM) complicated by microalbuminuria. Therefore, the microproteinuric and renal hemodynamic responses to exogenous NE infusions were measured in eight matched normoalbuminuric IDDM patients (group D1), microalbuminuric IDDM patients (group D2), and control subjects (group C).

Norepinephrine-induced blood pressure rise and renal vasoconstriction are not attenuated by enalapril treatment in microalbuminuric IDDM.

Background: In non-diabetic subjects, an attenuated systemic norepinephrine (NE) responsiveness may contribute to the mechanisms of action of angiotensin-converting enzyme (ACE) inhibitor treatment. We determined whether ACE inhibitor treatment influences systemic and renal haemodynamic responsiveness to exogenous NE, as well as urinary albumin excretion during NE, in microalbuminuric insulin-dependent diabetic (IDDM) patients, representing a patient category that benefits by strict blood pressure control.

Methods: In seven microalbuminuric IDDM patients, systemic and renal responsiveness to NE, infused at individually determined threshold [deltamean arterial pressure (MAP)=0 mmHg], 20% pressor (deltaMAP=4 mmHg) and pressor (deltaMAP=20 mmHg) doses, were compared before and after 8 weeks treatment with enalapril, 10 mg daily.

Deficits of attention after closed-head injury: slowness only?

The performance of a group of 60 severely closed-head-injured patients in the subacute stage of recovery on a series of tests addressing focused, divided, and sustained attention, and supervisory attentional control was compared to the performance of a matched group of 60 healthy controls. Patients performed significantly worse on each test with time pressure (those addressing focused and divided attention), indicating basic slowness of information processing, and on the self-paced tasks for supervisory attentional control. No indication was found of a sustained attention deficit.

The influence of the mobility in the cervicothoracic spine and the upper ribs (shoulder girdle) on the mobility of the scapulohumeral joint.

Objective: To examine the influence of the cervicothoracic spine and upper ribs (shoulder girdle) on glenohumeral mobility and the development of shoulder complaints.

Data Collection And Synthesis: Literature was collected by a search in Medline and Embase for English, German and Dutch publications, by further checking references in the articles found and by perusal of already collected literature regarding shoulder research. Articles referring directly or indirectly to a mutually influencing anatomical connection between the cervicothoracic spine, upper ribs (shoulder girdle) and scapulohumeral joint were selected during a consensus meeting of all reviewers.

Increased urinary IgG/albumin index in normoalbuminuric insulin-dependent diabetic patients: a laboratory artefact.

The previous observation that urinary IgG excretion is increased in normoalbuminuric insulin-dependent (IDDM) patients is unexplained and could possibly be related to a laboratory phenomenon. When untreated urine samples were stored -20 degrees C for 2 to 4 weeks, the IgG/albumin Index (IgG clearance divided by albumin clearance) was higher in normoalbuminuric IDDM patients than in control subjects (0.91 (0.

Influence of ambient plasma noradrenaline on renal haemodynamics in type 1 (insulin-dependent) diabetic patients and healthy subjects.

Imbalances in renal vasodilatory and vasoconstrictive mechanisms are responsible for the renal haemodynamic changes observed in Type 1 diabetes mellitus. Animal experiments have shown that noradrenaline (NA) infusion increases the intraglomerular pressure by predominantly efferent arteriolar vasoconstriction. The relationships between ambient plasma NA levels and renal haemodynamics were studied in 18 healthy control subjects (group C); in 17 normoalbuminuric diabetic patients (group D1) (albumin excretion rate (Ualb V) < 20 micrograms min-1), and in 17 microalbuminuric Type 1 diabetic patients (group D2) (UalbV 20-200 micrograms min-1), all patients being without overt autonomic neuropathy.

Spared recognition capacity in elderly and closed-head-injury subjects with clinical memory deficits.

This study describes the performance of three groups of subjects on a pictorial forced-recognition task, the Hundred Pictures Test. The aim was to determine whether subjects with memory deficits (elderly and closed-head-injured subjects) would perform as well as healthy young subjects, both on immediate and very long-term recognition. The results indicate that memory for complex meaningful pictures is spared in subjects with an otherwise impaired memory, and that despite increasing forgetting rates with increasing retention intervals (up to 27 weeks), still no differences are found between performance of these subjects and healthy young controls.

Effect of ethanol on hepatobiliary transport of cationic drugs. A study in the isolated perfused rat liver, rat hepatocytes and rat mitochondria.

The effect of ethanol on the hepatic uptake of various cationic drugs was studied in isolated perfused rat livers, isolated rat hepatocytes and isolated rat liver mitochondria. In isolated rat hepatocytes and in isolated perfused rat livers, the uptake of the model organic cation tri-n-butylmethylammonium was found to be markedly stimulated by ethanol in a concentration-dependent fashion. The uptake of tri-n-butylmethylammonium at 1 microM was increased to 120% and 137% at 0.

Contributory roles of circulatory glucagon and growth hormone to increased renal haemodynamics in type 1 (insulin-dependent) diabetes mellitus.

The stimulatory effects of growth hormone (GH) and glucagon on renal function are well known, but it is uncertain whether these hormones are involved in the increase in renal function, characteristic of type 1 (insulin-dependent) diabetes mellitus. Therefore, the circulatory levels of GH and glucagon were measured in 10 type 1 diabetic patients with an elevated glomerular filtration rate (GFR > 130 ml min-1 1.73 m-2) and in 20 age and sex matched normofiltering patients (GFR ranging from 90-130 ml min-1 1.

Pharmacokinetic analysis and cellular distribution of the anti-HIV compound succinylated human serum albumin (Suc-HSA) in vivo and in the isolated perfused rat liver.

After intravenous injection of a low dose (25 micrograms/kg) in rats, the anti HIV-1 compound succinylated human serum albumin (Suc-HSA) is taken up mainly in the liver and spleen and is proteolytically degraded. Ten minutes after injection of 125I-Suc-HSA, 72 and 14% of the dose were found in the liver and spleen, respectively. With immunohistochemistry we demonstrated that in both organs, Suc-HSA was specifically endocytosed in endothelial cells.

Modulators of the protein kinase C system influence biliary excretion of cationic drugs.

To investigate whether hepatobiliary transport of organic cations is under regulatory control, we studied transport of tri-n-butylmethylammonium in the isolated perfused rat liver and in isolated rat hepatocytes. Transport was investigated in the presence of modulators of the protein kinase C and the cyclic AMP second-messenger system. In the isolated perfused rat liver, it was observed that compounds modulating protein kinase C activity clearly affected the biliary excretion process of the cation tri-n-butylmethylammonium.

Novel, negatively charged, human serum albumins display potent and selective in vitro anti-human immunodeficiency virus type 1 activity.

We prepared a series of modified proteins and peptides by derivatizing the positively charged epsilon-amino groups of the lysine amino acids through reaction with anhydrides of succinic acid (Suc) and aconitic acid (Aco). Human serum albumin (HSA) was modified by introduction of a single carboxylic group (Suc-HSA) or two carboxylic groups (Aco-HSA) per amine function, yielding strongly negatively charged compounds. The in vitro anti-human immunodeficiency virus (HIV)-1 IC50 of Suc-HSA was about 1 microgram/ml, and the most polyanionic modified albumin of the series (Aco-HSA) exhibited an IC50 as low as 0.

Differential effects of metabolic inhibitors on cellular and mitochondrial uptake of organic cations in rat liver.

The effects of several metabolic inhibitors on the uptake of tri-n-butylmethylammonium (TBuMA) were studied in isolated rat liver mitochondria, isolated rat hepatocytes and isolated perfused rat livers, in order to characterize further the mechanisms for carrier-mediated uptake and cellular accumulation of organic cations in the liver. Treatment of isolated hepatocytes with valinomycin, carbonylcyanide-m-chlorophenyl-hydrazone (CCCP), dinitrophenol, oligomycin or antimycin resulted in a rapid decrease in cellular ATP within 3 min of addition. The initial uptake rate of TBuMA was generally largely affected by these treatments.

A multispecific uptake system for taurocholate, cardiac glycosides and cationic drugs in the liver.

To test the hypothesis of multiplicity in carrier-mediated uptake mechanisms for organic cations in the liver and to study the possible relation with bile acid and cardiac glycoside uptake mechanisms, mutual interaction during uptake of various radiolabeled quaternary amines has been studied in isolated rat hepatocytes. Inhibition patterns at low concentrations (1 microM) of the presumed type I monovalent organic cation tri-n-butylmethylammonium were markedly different from those at relatively high concentrations (25 microM). Both the cardiac glycoside K-strophantoside and the bile acid taurocholate clearly reduced the uptake rate of tri-n-butylmethylammonium at 25 microM whereas these agents completely failed to reduce the uptake at low concentrations of the cation.

Effect of a somatostatin analogue, octreotide, on renal haemodynamics and albuminuria in acromegalic patients.

Although insulin-like growth factor I increases renal function, the renal haemodynamic abnormality underlying the glomerular hyperfiltration in acromegaly is unknown. In normal subjects, amino acids and low doses of dopamine increase the glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), presumably by a predominant vasodilation of the afferent and efferent glomerular arterioles, respectively. We studied baseline GFR and ERPF (determined with 125I-iothalamate and 131I-hippuran, respectively), the renal stimulatory effects of amino acid and dopamine infusion, and albuminuria before and after 3 months octreotide treatment in seven acromegalic patients with metabolically active disease.

Inhibin as a marker for granulosa cell tumor.

In order to determine whether serum-immunoreactive inhibin could constitute a biochemical marker for the presence and progression of ovarian granulosa cell tumors and their metastases, we measured immunoreactive inhibin concentrations in series of serum samples obtained from 8 patients with granulosa cell tumor. Six series were tested in retrospect. From these, three came from patients who had been treated with an abdominal hysterectomy and bilateral salpingo-oophorectomy.

Inhibin as a marker for granulosa-cell tumors.

Inhibin is a peptide hormone normally produced by ovarian granulosa cells. It reaches a peak of 772 +/- 38 U per liter in the follicular phase of the menstrual cycle and is undetectable in the serum of menopausal women. To determine whether measurements of serum inhibin levels would provide a biochemical marker of the presence or progression of ovarian granulosa-cell tumors and their metastases, we measured the serum immunoreactive inhibin concentrations in six women with such tumors.

The relation of fertility and ovarian histology after bilateral ovarian wedge resection.

The immediate and long term fertility after bilateral ovarian wedge resection in 53 women with clomiphene citrate-resistant hyperandrogenic chronic anovulation is related to the histology of the ovarian wedges. Patients with polycystic ovaries and hyperplastic stromal abnormalities had most spontaneous conceptions and a normal fertility during follow-up. Apparently, chronic anovulation in these cases had been caused by ovarian disease in the face of normal hypothalamic function.

Apparent movements induced by luminance modulations: a model study.

When the receptive-field profiles of the different units in the primary visual cortex are described by a series of different functions which are given by a Gaussian distribution and its first, second, and so on, spatial derivatives, a full analysis of the input-output processing of these units (under the assumption of linearity for small signals) can be achieved for a wide variety of optical stimuli consisting of closely adjacent fields modulated independently in intensity. Once the input-output relationship for one particular unit has been obtained, it is possible to calculate in a straightforward manner the spatial representation of the stimulus pattern in a two-dimensional distribution of such units. Investigations are reported into how a stimulus pattern (a dark or bright bar between two fields modulated in illuminance) is represented in a hierarchical structure of such layers of units, each layer containing just one type of receptive-field profile from the Gaussian family of derivatives.

Letter processing in dyslexic subgroups.

Hypothesized cognitive strengths and weaknesses of three dyslexic subgroups (Boder and Jarrico 1982) were examined in two reading related experiments. The first experiment tested the prediction that auditorily presented letter sets should be processed better by dyseidetic than by dysphonetic readers. The prediction was not confirmed.