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Biomedical subjects

R Blank

Publications and source records attributed to R Blank.

At least 19 recordsLinked to original sources
PubMed2004

Identifying early treatment failure on category I therapy for pulmonary tuberculosis in Lima Ciudad, Peru.

SETTING: Ambulatory, public tuberculosis treatment facilities, central Lima, Peru. OBJECTIVE: To identify risk factors for failure on directly observed Category I therapy. DESIGN: Case-control study. All failures of Category I (2HREZ/4H2R2) therapy in 2000 (2.9% of smear-positive TB patients) were included as cases; two controls per case were matched on health center and approximate time of treatment initiation. RESULTS: The study included 38 cases and 76 controls, all new smear-positive, pulmonary TB patients treated with Category I therapy in central Lima in 2000. Neither treatment irregularity nor incidence of adverse events predicted failure in the study group. Mean baseline body mass index was lower in cases than in controls (P = 0.06). Cases gained less weight during therapy (P = 0.01). Smear positivity at 2 months of therapy was strongly associated with failure (OR 11.7; 95%CI 2.4-57.5). No controls had positive smears at or after 3 months of therapy (OR [corrected] 144.9; 95%CI 8.4-2500). Nearly 75% of cases with isolates tested for susceptibility to first-line drugs had multidrug-resistant TB (MDR-TB). CONCLUSION: A large proportion of failures on Category I therapy can be identified early. As three-quarters of patients with susceptibility results have MDR-TB, early referral for culture and drug susceptibility testing is critical for prompt initiation of appropriate therapy and improved outcomes.

Adolescent↗
PubMed2001

Human development of grip force modulation relating to cyclic movement-induced inertial loads.

The present study examines the development of grip force modulation relating to self-induced loads during repetitive vertical arm movements at different frequencies with a hand-held object. One hundred and thirty-four 3- to 6-year-old children and 16 adults were asked to move a lightweight object up and down at increasing rates from 0.5 Hz up to individual maximal arm movement rates (> 2.5 Hz). Grip forces were measured by a uni-axial force transducer and the inertial forces (tangential forces) were calculated from the measurements by accelerometers within the object. Generally, the quality of anticipatory grip force control improved from movement frequencies of 1 Hz to 2.5 Hz and decreased above 2.5 Hz. At movement frequencies below 1 Hz, the phase lag between grip and load force cycles was longer in children than in adults (children: median = 17 ms; adults: median = 0 ms); however, there were no significant differences between the age groups above 1.5 Hz. The grip-to-load force ratio and the grip force modulation were not significantly different from the adults up to 2.5 Hz. The fine coupling of grip and load forces (precise temporal and gain control) showed age effects among the 3- to 6-year-old children, mainly between 3- and 4-year-olds, and in adults extremely good coupling at medium arm movement frequencies. However, concerning the pure temporal coordination of grip and inertial forces, there were only differences between the 3-year-old children and the other groups at arm movement frequencies above 2.5 Hz. The results show that, during cyclic movements with hand-held loads, temporal control is well established at the age of 4 years whereas the fine gain control needs a longer time to develop. The anticipatory control is dependent on the arm movement frequency and, therefore, how rapidly the inertial loads change. The high level of anticipatory control during self-induced repetitive actions in children of 3-6 years of age is interpreted as an early developing ability to predict precisely cyclic self-induced inertial loads of hand-held objects when the object properties are known by proprioception. The timing, which is possibly related to cerebellar functions, is, to some extent, developed earlier than the gain control, which may be associated with cortical functions.

Adult↗
PubMed2000

Human motor development and hand laterality: a kinematic analysis of drawing movements.

This study examines the developmental profiles of basic 'open-loop' drawing movements on the non-dominant hand (ND) in comparison with the dominant hand (D). Fifty-three right-handed children aged 7-14 years and 15 adults aged 27-43 years were examined. Each subject drew lines and circles of different sizes at maximum velocity with a pressure-sensitive pen on a computer graphics tablet. Small lines were drawn at 90 degrees to the axis of the forearm (lines using wrist movements (LWM)) and along the axis of the forearm (lines using elbow movements (LEM)). Larger lines were drawn at 90 degrees to the axis of the forearm (LEM). At both extremities, the movement frequencies of the proximally generated drawing movements increased in a parallel fashion at different levels. In LWM, the right-left-differences (RLD) were high in 7- to 8-year-old children; until puberty, the ND hand reached almost the performance of the D hand. In contrast, the RLD of the LFM increased at the same time. As adulthood approaches, frequencies of all drawings increased further while the LWM on the ND side remained stable. In adults, there were similar RLD for all line drawings involving predominantly flexion and extension movements. When drawing circles, the RLD were highest, though stable in all age groups. Hand laterality of pen use changes over time; these changes are dependent on complexity (combined/sequential cf. flexion-extension muscle activation) and on topography (proximal cf. distal movements). Distinct developmental profiles of motoneuronal populations of the cortex may be responsible for the distinct hand laterality effects and the decreasing variability of motor patterns. The drawing abilities and developmental changes on the untrained ND hand indicate that effector-specific practice plays a minor role.

Adolescent↗
PubMed2000

Development of externally guided grip force modulation in man.

We examined the development of externally guided changes of grip force with respect to force rate and direction of force change. Sixty-nine children, 3-6 years of age, and 17 adults produced increasing or decreasing isometric forces on a small cylindrical sensor using a pinch grip with visual feedback. Force changes were instructed with a visual tracking task. Ramp-like paradigms with both force increase and force decrease and two different target force rates were used (0.5 N/s, 1.25 N/s). Precision of force tracking showed clear age effects and was influenced by the required force rates and directions of force change. In adults, tracking errors were much more dependent on target force rate and direction than in children. Up to four years of age, the children tended to overshoot the target force change in a 'jump and wait' manner in all conditions except for fast target force decreases. Older children tended to overshoot only in the condition with slow target force decrease. Adults showed close undershooting in all conditions when following the target. Adults used either a continuous 'following' strategy or a 'see and catch-up' strategy. The distinct effects on tracking errors suggest an age-related change of strategies from a feedforward strategy with intermittent use of sensorimotor feedback towards a fairly parallel and well-integrated feedback and feedforward processing. A critical age appears to be around five to six years. We suggest that these age effects may reflect distinct developmental velocities of neuronal subpopulations of the cortex and of the cerebello-cortical connections.

Adult↗
PubMed1999

Externally guided control of static grip forces by visual feedback-age and task effects in 3-6-year old children and in adults.

This study has been devised to examine the visual feedback control of static grip force levels by pinch and by hand grip during pre-school age and in adults. 69 3-6-year old children and 17 adults were asked to establish and hold grip force levels defined by a visual target and feedback on the dominant and non-dominant hand by hand grip and by pinch grip. From 3 to 6 years of age, the time needed to establish requested grip force levels decreased by a third and the precision increased two-fold for hand grip but four-fold for pinch grip; in contrast to younger children, 5-6-year olds showed a marked superiority of 60% for the pinch grip compared to hand grip, decreasing to about 40% in adults. In the case of pinch grip, all individuals had worse results on higher force levels (children: 50%, adults: 32%). The young children generally tended to use too much force. Older children and adults were better by 75% under the condition of visual feedback vs. internal proprioceptive control (after withdrawing visual feedback). In contrast to previous findings in anticipatory grip force regulation, externally guided force regulation begins to develop during late nursery age. Specific developmental effects were found for grip style and for the ability to use visual feedback and to change from external to internal (proprioceptive) control, and to a lesser extent for force magnitude but not for hand laterality and gender. The findings are interpreted by different developmental velocities of motor areas which are responsible for force regulation mechanisms and for grip style.

Adult↗
PubMed1999

Effects of age on distally and proximally generated drawing movements: a kinematic analysis of school children and adults.

The effects of age on basic fine motor functions were assessed using a kinematic analysis of simple repetitive drawing movements in a sample of 53 right-handed children aged 7 to 14 years 11 months and 16 adults aged 27 to 54 years with no detectable abnormality with neurological examination. Lines, circles, and half-circles were drawn at a self-chosen and maximum velocity with a pressure-sensitive pen on a computer graphics tablet. Patterns generated by finger, wrist, and arm movements, and those generated by combined finger-wrist movements with and without a change in the drawing direction were analysed. The frequencies of all movement patterns increased until adulthood: 0.1 Hz per year for half-circles, 0.15 to 0.2 Hz per year for circles and lines generated by arm and wrist movements. The greatest increase (0.35 Hz per year) was observed for lines produced by finger movements. Differences in movement frequencies between finger versus wrist or arm movements when drawing lines decreased from about 3 Hz in 7- to 8-year-olds to 0.5 to 1 Hz in adolescents. In adults the difference between maximum finger, wrist, and arm movement frequencies decreased to almost zero. In contrast, the differences in movement patterns with and without change in direction remained stable until adulthood. Based on these results it is hypothesized that the differential effects of finger and more proximally generated movements on age reflect maturation of distinct neuronal sites of the corticostriatal-cerebellar circuit rather than acquisition of motor skills or myelinization of corticospinal pathways.

Adolescent↗
PubMed1999

Effect of fumaric acid and dietary buffering capacity on ileal and fecal amino acid digestibilities in early-weaned pigs.

Experiments were conducted to determine the effect of fumaric acid supplementation and buffering capacity of the diet on ileal and fecal digestibilities of CP, GE, and amino acids in early-weaned pigs. In two experiments, 12 pigs each were weaned at 14 d of age and fitted with a simple T-cannula at the distal ileum between 15 and 17 d of age. In both experiments, the pigs were fed four diets, based on wheat and soybean meal without (control) or with 1, 2, or 3% fumaric acid according to a balanced two-period change-over design. In Exp. 2, the buffering capacity of the diets was increased by supplementation of 3% sodium bicarbonate. The pigs were fed three times daily: equal amounts at 8-h intervals. The diets were supplied at a rate of 5% (wt/wt) of body weight. The inclusion of fumaric acid to the diet with a low buffering capacity increased (P < .05) the ileal digestibilities of CP, GE, and the majority of amino acids. The highest responses were found at an inclusion level of 2% fumaric acid. The improvements in apparent ileal amino acid digestibilities ranged from 4.9 to 12.8 percentage units. Supplementation of fumaric acid to a diet with a high buffering capacity led only to numerical increases in ileal digestibilities of CP, GE, and amino acids. In both studies, fumaric acid supplementation had no effect (P > .05) on the fecal digestibilities of CP, GE, and amino acids, except histidine. A high buffering capacity of the diet decreased the ileal amino acid digestibilities by 1 to 10 percentage units compared with diets with the low buffering capacities. In both experiments, ileal and fecal digestibilities were higher (P < .05) in Period 2 (on d 24 after weaning) than in Period 1 (on d 11 after weaning). A positive correlation (P < .05) between ileal digestibilities and fumaric acid supplementation to the diets with the low buffering capacities was observed in Period 1 (on d 11 after weaning), but not in Period 2 (on d 24 after weaning). No relationship (P > .05) between ileal digestibilities and fumaric acid supplementation to the diets with a high buffering capacity could be established. In conclusion, supplementation of fumaric acid to starter diets during the first 3 to 4 wk after weaning increases the ileal digestibilities of GE, CP, and amino acids.

Amino Acids↗
PubMed1997

[Clinical value of Doppler ultrasound controlled puncture of the inguinal vessels with the "Smart Needle" within the scope of heart catheter examination].

Due to the increasing number of diagnostic heart catheterizations, especially in elderly patients, as well as the increase of percutaneous transluminal coronary angioplasties, we are confronted with a rise in peripheral complications evolving from difficulties in the procedure of the puncture of the femoral artery or vene. The development of greater hematomas in the area of the puncture, the formation of arterio-venous fistulas and aneurysma spuria are the foremost complications. It was the aim of the study to investigate in as far an improved puncture technique could reduce the rate of peripheral complications. In this comparative study the vessel punctures were carried out by the conventional Judkins puncture technique and a new method using a special puncture needle. (Smart Needle" R), with an integrated ultrasonic sound device. In this study 114 patients--age 23 to 82 years--undergoing heart catheterization (91 diagnostics, 23 PTCAs) were examined. In all cases a puncture of the arterial and venous femoral vessel was done. 50 patients received a puncture via "Smart Needle" and the remaining 64 patients were punctured conventionally. In contrast to the group of patients receiving conventional puncture of the femoral artery, where in 72% more than one try was needed, in all patients of the "Smart Needle" group the first puncture was successive. Concerning the puncture of the venous vessels no significant difference between the two groups was observed. This difference between arterial and venous puncture outcome results from the difference between arterial and venous flow signals detected by the ultrasonic sound device. As to the bleeding complications hematomas following to "Smart Needle" puncture occurred less frequently-in 25%--and were significantly smaller than in the conventional group where hematomas were seen in 46%. The number of patients with hematomas with diameters of more than 5 cm was twice as high in the conventionaly punctured group (28%) than in the "Smart Needle" group (14%). However, patients suffering from arterial hypertension or hemostatic disorders showed an increased risk of vascular complications. In regard to the cost-benefit relation an indication for the use of the new technique is to be seen especially in overweight patients and patients suffering to aortic stenosis or cardiogenic shock.

Adult↗
PubMed1997

Ambulatory monitoring of children's activity.

One of the difficulties in clinical assessment is how to obtain accurate data in the "real world". This paper describes the Dynaport ADL Monitor, an accelerometry-based system for ambulatory monitoring of the activities of daily living (ADL). In previous studies the monitor has proved a success with adults. To validate the system for use with children, 9 h of various activities conducted by nine children were measured and videotaped at the same time. All postures and activities were divided into one of five main categories: standing, sitting, lying, locomotion and swing/seesaw. The video pictures were evaluated by an observer. Independent of this, the acceleration signals were translated by the DynaPort ADL monitor software, and were compared to the video pictures. Minimal and maximal validity percentages were calculated for each of the main classes, for each individual measurement and overall. To estimate monitoring performance the 10 sets of measurements are regarded as representative samples of children's daily activity. The overall minimal and maximal validity are 73.15 +/- 1.96 x 4.48 and 91.31 +/- 1.96 x 1.75 weighed standard deviation.

Activities of Daily Living↗
PubMed1996

[Effect of an oligo-antigen diet on the behavior of hyperkinetic children].

The influence of an oligoantigenic diet on different dimensions of the behavior of 21 children diagnosed as having attention-deficit hyperactivity disorder (ADHD) was examined. Treatment effects were assessed with three subjective measures (two questionnaires and an interview) and three objective measures (two attention tests and actometer). The study was divided into three phases: baseline, diet and provocation, each lasting three weeks. A crossover design was used. A significant effect was found for the subjective measures, but not for the objective measures. The results are discussed in terms of possible types of effects, e. g. rater effects and environmental effects. It may be that the oligoantigenic diet influences only certain dimensions of hyperactivity.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

Reduced risk of liver-function-test abnormalities and new gallstone formation with weight loss on 3350-kJ (800-kcal) formula diets.

Weight loss in obese subjects ingesting very-low-energy (VLE; < 2510 kJ/d), low-fat (< or = 1 g/d) formula diets is associated with liver-function-test abnormalities and gallstone formation. It is unknown whether these abnormalities develop during treatment with diets higher in energy and fat. We prospectively studied liver-function tests and gallstone formation in 73 obese patients ingesting approximately 3500 kJ and 15-25 g fat daily for 10 wk. Two of 53 patients completing the protocol developed ultrasonographic gallstones during weight loss, a rate substantially lower than that observed with VLE diets. Trend analysis demonstrated significant increases in AST and ALT activities, but changes were less than those observed with VLE diets. Patients who developed gallstones had a significantly greater weight loss rate and larger increases in AST and ALT than did nonstone-forming patients. These results suggest that the risk of developing hepatobiliary abnormalities with dieting is lowered when subjects ingest greater amounts of energy and fat than that administered in earlier VLE-diet studies. Our results also highlight potential risk factors and markers of new gallstone formation.

Adult↗
PubMed1993

Influence of blood sampling from venipunctures and catheter systems on serial determinations of prothrombin activation fragment 1 + 2 and thrombin-antithrombin III complex.

To evaluate the influence of different blood sampling techniques on test results of thrombin-antithrombin III complex (TAT) and prothrombin fragment 1 + 2 (F1 + 2) serial determinations were performed. In six groups of nonrandomized patients (ten patients each) the concentrations of the coagulation markers of blood samples from central catheters (internal jugular, caval, Shaldon, pulmonary artery) and peripheral cannulas (17G and 18G) were compared with those of blood samples obtained simultaneously from direct venipunctures of the contralateral arm. Medians and 25th-75th percentiles of TAT and F1 + 2 concentrations of plasmas obtained from central catheters were not different from those taken from venipunctures. When delta mean values (catheter - venipuncture) were calculated negative results were obtained, indicating lower concentrations measured from blood sampled through central catheters with the exception of blood that taken from Shaldon catheters. Only for TAT concentrations significantly were lower values measured in blood samples taken from internal jugular catheters when compared with blood samples obtained from direct venipunctures. Significantly higher TAT concentrations were determined in blood samples obtained from Shaldon catheters. For both coagulation markers correlations were found between concentrations in blood samples from central catheters and venipunctures. In blood samples taken from peripheral venous cannulas only F1 + 2 concentrations correlated with the concentrations found in samples from direct venipuncture. In contrast to F1 + 2, TAT concentrations measured from blood samples via peripheral cannulas were determined significantly higher than those taken from direct venipunctures.(ABSTRACT TRUNCATED AT 250 WORDS)

Antithrombin III↗
PubMed1992

[Subgroups of hyperkinetic disorders--explorative studies with reference to questionnaires and immunologic parameters].

In this paper, the main questions examined are: 1. The relationship between clinically diagnosed hyperkinetic syndrome (HKS) and 3 questionnaires for parents (Child Behavior Checklist (CBCL) by Achenbach and Edelbrock, Enzephalopathie-Fragebogen by Meyer-Probst and 10-Item scale by Conners). 2. The relationship between the clinical psychiatric diagnosis and the questionnaires and allergological parameters. In order to answer these questions, a sample of 122 psychiatric patients with "extraversive" behavior disturbances (HKS: N = 104, other "extraversive" disorders, mainly conduct disorders (EVD): N = 18) was examined prospectively and sequentially. The preliminary results are: a) The children with HKS, the children with EVD and the children with HKS and conduct disorder could be differentiated by several subscales (Especially by "introversive" symptoms) of the CBCL and the Fragebogen by Meyer-Probst. The Conners scale showed significant differences between the groups on only one item. b) The children with HKS, especially those without conduct disorder, had two to three times as many allergies as the children with HKS and conduct disorders or those with EVD.

Attention Deficit Disorder with Hyperactivity↗