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Biomedical subjects

E Schechtman

Publications and source records attributed to E Schechtman.

13 recordsLinked to original sources
PubMed2003

Dynamic transperineal ultrasound vs. defecography in patients with evacuatory difficulty: a pilot study.

BACKGROUND AND AIMS: Defecating proctography has been traditionally used to assess patients with evacuatory dysfunction. More recently, dynamic transperineal ultrasound has been described, defining the interaction between the infralevator viscera and the pelvic floor at rest and during straining. This study compared qualitative diagnosis and quantitative measurement obtained by defecography and dynamic transperineal ultrasonography in patients with evacuatory difficulty. PATIENTS AND METHODS: Thirty-three women were examined using both techniques with both examiners blinded to the results of the other method. Quantitative measurement was made of rectocele depth, anorectal angle (at rest and during maximal straining) and anorectal junction position at rest and movement during straining. RESULTS: There was good agreement for the diagnoses of rectocele, rectoanal intususseption, and rectal prolapse. Dynamic transperineal ultrasound was more likely than defecography to make multiple diagnoses or to diagnose an enterocele when a rectocele was present. There was no difference noted between the two techniques for the measurement of anorectal angle at rest, anorectal junction position at rest, or anorectal junction movement during straining. The mean anorectal angle during straining was 123.3+/-4.3 degrees as measured by defecography and 116.4+/-3.3 degrees as measured by dynamic transperineal ultrasound, nearly reaching statistical significance. CONCLUSION: Dynamic transperineal ultrasound is a simple and accurate technique for assessment of the pelvic floor and soft-tissues in patients with evacuatory dysfunction.

Adult↗
PubMed2001

Head stabilization in herons.

We examined head stabilization in relation to body mass and length of legs in four heron species (little egrets, Egretta garzetta; night herons, Nycticorax nycticorax; squacco herons, Ardeola ralloides; and cattle egrets, Bubulcus ibis: Aves: Ardeidae). Head stabilization, under controlled, sinusoidal, perch perturbations was mostly elicited at frequencies lower than 1 Hz. Maximal perturbation amplitudes sustained were positively correlated with leg length and maximal perturbation frequencies sustained were negatively correlated with body mass and with leg length. The species differed significantly in average maximal perturbation amplitudes sustained. Combinations of amplitude and frequency for which stabilization was achieved were bounded by a decreasing concave "envelope" curve in the frequency-amplitude plane, with inter specific differences in "envelope". As physical constraints, we tested maximal vertical acceleration, which translates into a line defined by the product of frequency2 x amplitude, and maximal vertical velocity, which translates into a line defined by the product of frequency x amplitude. Both relations were in good agreement with the experimental results for all but squacco herons. The results support predictions based on mechanical considerations and may explain the predominance of motor patterns employed by herons while foraging.

Animals↗
PubMed2001

Self-reports of safe driving behaviors in relationship to sex, age, education and income in the US adult driving population.

This study analyzed the data of a health and safety survey conducted on a representative sample of the adult driving population. The analysis focused on the relationships between self-reported safe driving behaviors (including belt use, observing speed limits, and abstaining from drinking and driving), and demographic characteristics (including sex, age, education and income). The results showed that the three behaviors are quite independent of each other, and, contrary to some stereotypes, there is no single high-risk group that is most likely to violate all three safe driving behaviors. The only consistent effect was that of sex: women reported higher observance rates of all three behaviors. Reported use of safety belts increases with age and education for both men and women. However while for women the reported use increases with income, for males the reported use does not change with income. Complete avoidance of drinking and driving was reported by most drivers in all groups, and the high rates hardly varied across the different age, education, and income groups. The number of people who reported that they observe the speed limit all the time increased with age, but decreased with increasing education and income. The results have implications for identifying violation-specific high-risk groups, and stressing different factors for each.

Adult↗
PubMed2001

Mental and motor switching in Parkinson's disease.

Switching difficulties in Parkinson's disease (PD) are expressed in both mental and motor tasks. The authors of the present study investigated whether those deficits coexist in the same patient and are positively correlated. They tested 8 nondemented PD patients and 6 age-matched control participants by using the modified Wisconsin Card Sorting Test and a motor switching paradigm that is based on the task of reaching toward visual targets, the location of which could unexpectedly be altered within the reaction time. In both mental and motor tasks, patients performed significantly worse than controls. There were no significant correlations between the two types of pathology in individual patients. Mental and motor switching deteriorate in PD patients, but the deficits are not necessarily of parallel severity.

Aged↗
PubMed2001

Antivascular treatment of solid melanoma tumors with bacteriochlorophyll-serine-based photodynamic therapy.

We describe here a strategy for photodynamic eradication of solid melanoma tumors that is based on photo-induced vascular destruction. The suggested protocol relies on synchronizing illumination with maximal circulating drug concentration in the tumor vasculature attained within the first minute after administrating the sensitizer. This differs from conventional photodynamic therapy (PDT) of tumors where illumination coincides with a maximal concentration differential of sensitizer in favor of the tumor, relative to the normal surrounding tissue. This time window is often achieved after a delay (3-48 h) following sensitizer administration. We used a novel photosensitizer, bacteriochlorophyll-serine (Bchl-Ser), which is water soluble, highly toxic upon illumination in the near-infrared (lambda max 765-780 nm) and clears from the circulation in less than 24 h. Nude CD1 mice bearing malignant M2R melanotic melanoma xenografts (76-212 mm3) received a single complete treatment session. Massive vascular damage was already apparent 1 h after treatment. Changes in vascular permeability were observed in vivo using contrast-enhanced magnetic resonance imaging (MRI), with the contrast reagent Gd-DTPA, by shortening spin-spin relaxation time because of hemorrhage formation and by determination of vascular macromolecular leakage. Twenty-four hours after treatment a complete arrest of vascular perfusion was observed by Gd-DTPA-enhanced MRI. Histopathology performed at the same time confirmed primary vascular damage with occlusive thrombi, hemorrhage and tumor necrosis. The success rate of cure of over 80% with Bchl-Ser indicates the benefits of the short and effective treatment protocol. Combining the sensitizer administration and illumination steps into one treatment session (30 min) suggests a clear advantage for future PDT of solid tumors.

Animals↗
PubMed1999

Cattle egrets are less able to cope with light refraction than are other herons.

The majority of heron species (Aves, Ardeidae) forage on aquatic prey in shallow water. Prey detection, aiming and the beginning of the capture strikes are performed while the heron's eyes are above water. For most angles, as a result of air/water light refraction, the apparent image available to a heron is vertically displaced from the prey's real position. Herons must therefore correct for refraction. We tested the hypothesis that species that forage in aquatic habitats should be more able to correct for image disparity than those of terrestrial habitats. The ability of hand-reared herons of four species to capture stationary prey (fish) underwater (submerged) or in air (aerial) was tested. Three species (little egret Egretta garzetta, squacco heron Ardeola ralloides, and night heron Nycticorax nycticorax) normally forage in aquatic habitats while the fourth (cattle egret Bubulcus ibis) forages in terrestrial habitats. No individuals missed aerial prey. Success rates of little egrets and of squacco herons with submerged prey were high, while night herons became less successful with increased prey depth and/or distance. In cattle egrets, success rate was low and negatively correlated with prey depth. The observed interspecific differences may thus be related to (1) differential ability to correct for air/water light refraction and (2) the species' foraging behaviour. We suggest that cattle egrets are in the process of losing their ability to cope with submerged prey. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Trends in safe driving behaviors and in relation to trends in health maintenance behaviors in the USA: 1985-1995.

Specific health and safe driving behaviors of the American adult population during the period 1985-1995, were examined for trends and for consistencies in observing them. The data base consisted of the results of annual surveys conducted on representative samples of 1250 people of the US adult population. Two indices were developed: a Health Index (HI) and a Safety Index (SI). The Health Index reflects the level of practice of six health and disease preventing behaviors (in order of decreasing importance: not smoking, frequent exercises, avoiding fat foods, having an annual blood pressure test, avoiding high-cholesterol foods, and having an annual dental exam). The Safety Index reflects the level of practice of three safe driving behaviors (in order of decreasing importance: wearing safety belts, avoiding drinking and driving, and observing the speed limit). Only a weak association was found among the individual safe driving behaviors, among the individual health maintenance behaviors, and between the two sets of behaviors. Over the 11-year study period the change in the Health Index has been practically and statistically insignificant, whereas the change in the Safety Index was both statistically and practically significant. The small improvement in the Safety Index actually masked a complex pattern of changes in safe driving habits. The three component Safety Index behaviors did not change in the same manner over the 11-year period. The greatest and most consistent increase was in the use of safety belts, with the reported percent who use it all the time increasing from 41.5% in 1985 to 74.1% in 1995 (an increase of 80%). There was also a consistent positive trend in refraining from drinking and driving, but the overall improvement was less dramatic than that reported for use of safety belts: from 71.6% reporting they never drink and drive in 1985 to 79.1% in 1995 (an increase of 10%). Still, it is noteworthy that by 1995 nearly 80% of the people reported they never drink and drive. Finally, obeying the speed limit did not improve over the 11-year period.

Accidents, Traffic↗
PubMed1998

Motor switching abilities in Parkinson's disease and old age: temporal aspects.

OBJECTIVES: To investigate capabilities of arm trajectory modification in patients with Parkinson's disease and elderly subjects using a double step target displacement paradigm. METHODS: Nine patients with Parkinson's disease and seven age matched control subjects were instructed to move a stylus towards visual targets presented on a digitising table. Within each session, in some trials the target location was changed before initiation of movement and the subjects were to modify their movements towards the new target (switching trials). In other trials the target location was not changed (control trials). This procedure was repeated for four different target configurations, using interstimulus time intervals of six different durations. The subjects' hand trajectories were recorded and their kinematic characteristics were analysed. RESULTS: In switching trials, about 40% of the movements were aimed directly toward the final target location in both groups. When the trajectories were initially directed toward the first target and then modified toward the second, the reaction time (RT) to the second stimulus (RT2) was longer than to the first stimulus (RT1). The RT2/RT1 ratio was significantly larger in patients with Parkinson's disease than in healthy elderly subjects. CONCLUSIONS: Patients with Parkinson's disease and elderly subjects are substantially slower in responding to a required modification of their movement than in responding to the required movement initiation. Patients with Parkinson's disease have impaired capabilities in processing simultaneously the motor responses to two visual stimuli presented in rapid succession.

Aged↗
PubMed1996

Double-blind comparison of cabergoline and bromocriptine in Parkinson's disease patients with motor fluctuations.

In the present study we compared the efficacy and safety of the new dopamine agonist cabergoline (CBG) with bromocriptine (BCR) in Parkinson's disease (PD). CBG has a very long half-life and can be administered as a single daily dose. Forty-four PD patients with uncontrolled motor fluctuations participated in the study. Patients were randomly and blindly assigned to equivalent doses of either CBG or BCR in addition to preexisting levodopa. Dosage was titrated to optimal, using up to 6 mg of CBG or 40 mg of BCR daily. CBG was given as a single morning dose whereas BCR was administered tid. Sixteen patients were followed for 1 year and 16 additional patients for 6 months. The mean follow-up duration was 9 +/- 5 months. The main effect of both drugs was observed on motor UPDRS scores, rigidity, bradykinesia items, and the percentage of awake hours spent during "on" and "off". In general, the effect of CBG was similar to that of BCR. The percentage of awake hours spent during "on" was higher with CBG as compared with BCR. Adverse events included dyskinesias, orthostatism, confusion, edema, and paresthesias in limbs. These effects were seen at similar frequencies with both drugs. The study shows that CBG given as a single morning dose is at least as efficacious as BCR given tid. CBG is a promising dopamine agonist for the treatment of motor fluctuations in PD.

Aged↗
PubMed1995

Kinematic properties of upper limb trajectories in idiopathic torsion dystonia.

The kinematic properties of upper limb trajectories of simple reaching movements have been analysed in patients with idiopathic torsion dystonia (ITD). The velocity profiles differed from those of neurologically healthy subjects by being less symmetric. In several patients movement execution was slow due to a longer deceleration time. This phenomenon was even more conspicuous in the absence of visual feedback from the limb and was accompanied by a significant decrease in the final accuracy. These findings show that patients with ITD have deficits in central motor mechanisms beyond abnormal muscle activation patterns. Similarities between kinematic properties of patients with ITD and patients with Parkinson's disease including the deterioration of motor performance in ITD in the absence of visual feedback from the limb, suggest the existence of abnormalities in sensorimotor integration in both diseases.

Adult↗
PubMed1992

Kinematic analysis of upper limb trajectories in Parkinson's disease.

The purpose of this study was to analyze the kinematic properties of upper limb trajectories in Parkinson's disease (PD) patients and to investigate the role of visual feedback from the moving limb. Beyond the characteristic bradykinesia, PD patients differed from controls by generating hand trajectories with asymmetrical velocity profiles that lacked smoothness and were composed of a short initial accelerative phase, followed by a prolonged interval composed of alternating decelerative and accelerative phases. In both groups, the reaction times for movements directed away from the body were longer than for movements directed toward the body; this effect was accentuated in PD. In both groups, initial peak accelerations were significantly larger for distally as compared to proximally directed movements. In the absence of visual feedback from the limb a deterioration in the accuracy of reaching the target was observed in both control and PD patients only for distally directed movements. However, this deterioration and the effect of target location on final accuracy was substantially larger in PD. Taken together, our study suggests that in PD visual information is continuously relied upon for ongoing movement correction, therefore accentuating the bradykinesia. The deficit in final accuracy in the absence of visual feedback reflects the important role played by the basal ganglia in sensorimotor integration.

Acceleration↗
PubMedDate not supplied

A comparison of dopamine agonists and catechol-O-methyltransferase inhibitors in Parkinson's disease.

To compare the efficacy and tolerability of three dopamine agonists--pergolide (PRG), pramipexole (PRX), and ropinirole (ROP)-and two catechol-O-methyltranferase (COMT) inhibitors-tolcapone (TOL) and entacapone (ENT)-as add-on therapies to levodopa (L-Dopa) in Parkinson's disease, we analyzed randomized, double-blind, placebo-controlled, multicenter studies. To our knowledge, they had not yet been evaluated in comparison with each other. Statistical analyses used odds ratios, numbers needed to harm, and Fisher's inverse chi2 method. Seven studies meeting the inclusion criteria included treatment of 1,756 patients. The common efficacy measures were the reduction of L-Dopa dose and "off' duration. The reported reduction in L-Dopa dose was significant for all drugs in relation to placebo, but was most significant for PRX and ENT (p < 0.0001). The most significant reduction in "off' duration was with PRG, PRX, and ENT (p < 0.001). The common tolerability measures were the percentage of patients withdrawn because of side effects, because of any reason, and because of the development of dyskinesias. Ropinirole, PRX, and ENT caused fewer withdrawals related to side effects. Pergolide was better than other analyzed drugs concerning withdrawals for any reason. All drugs caused more dyskinesias than placebo (p < 0.0001), with overlapping confidence intervals, except for TOL 600 mg, which caused more dyskinesias than dopamine agonists and ENT. Pramipexole and ENT had the best efficacy and tolerability profile in this analysis.

Catechol O-Methyltransferase Inhibitors↗