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Biomedical subjects

K H Labs

Publications and source records attributed to K H Labs.

33 records · Page 2Linked to original sources
PubMed1996

HWA 285 (propentofylline)--a new compound for the treatment of both vascular dementia and dementia of the Alzheimer type.

The pharmacological profile of HWA 285 favors its use in patients with both Alzheimer's disease (PDD) and/or vascular dementia (MID). Clinical trials showed clinically relevant, statistically significant efficacy in the domains of cognitive function, global function and activities of daily living (ADL) in both PDD and MID. HWA 285 had a prolonged symptomatic effect for at least 12 months, although therapeutic effects were seen already after the first 3 months of treatment. HWA 285 was very well tolerated for at least 1 year.

Activities of Daily Living↗
PubMed1996

The pentoxifylline experience: exercise testing reconsidered.

This paper critically reviews the methodology used in clinical trials in chronic occlusive arterial disease (COAD) stage II (intermittent claudication) patients. The reasons for choosing internationally accepted standard treadmill settings as well as its limitations are discussed. Emphasis is put on the discussion of valid trial endpoints such as hemodynamic surrogates and clinically oriented parameters. Reasons for a spontaneous and treatment-unrelated improvement in claudication distance are elucidated, and variables which may be used for the definition of patient subsamples showing a high frequency of a pronounced treatment response (treatment responder populations) are presented. The magnitude of claudication distance improvement that might be considered clinically relevant is discussed in the light of the European Union guidelines for clinical trials in COAD patients. Results achieved with pentoxifylline are presented in context with all variables mentioned above.

Aged↗
PubMed1992

How useful are acceleration- and deceleration-based Doppler indices? A trial on patients with percutaneous transluminal angioplasty.

The usefulness of indices commonly used in Doppler sonography is limited; the aim of this study was to investigate if inclusion of systolic acceleration and deceleration patterns in Doppler indices will result in practical diagnostic advantages. Systolic delay time index (SDTI) and height-width index (HWI) are compared to Gosling's pulsatility index (PI) and to PI-based damping factors (DF) in patients with isolated lesions in the distal superficial femoral artery before and after percutaneous transluminal angioplasty (PTA). Before PTA, all indices distal to the lesion differ significantly from proximal indices. After successful PTA, none of the indices is able to detect the PTA outcome with sufficient sensitivity. The additionally defined curve broadening index (CBI) shows a 100% sensitivity for detecting PTA success in the examined patient population.

Aged↗
PubMed1992

The pre-stenotic Doppler shift signature.

In two series of measurements the Doppler shift signatures of 10 healthy volunteers were studied at varying distances proximal to a total reflection site, in order to describe parameters which are predictive for downstream lesions. Characteristic changes both in amplitude and time parameters were found; the most marked changes being the abolishment of a DC-component for monophasic signatures, the development or the augmentation of early diastolic reverse flow amplitudes together with a highly significant reduction in the signatures' systolic deceleration time. Maximum changes however tended to be localized at 2 to 4 centimeters upstream from the reflection site. Further upstream propagation was limited. Hence the time course of a Doppler signature and particularly its systolic deceleration should be taken into account in addition to the known resistance indices, if downstream lesions shall be predicted from upstream Doppler signatures. The limited upstream propagation of pre-stenotic Doppler signature changes restricts its diagnostic value to vascular segments where the region adjacent to a lesion is routinely scanned; thus diagnostic benefit can be expected for extracranial carotid artery disease but hardly for peripheral (lower limb) lesions.

Adult↗
PubMed1991

[Changes in the ultrasound power spectrum due to concentric stenoses of the femoral artery of the dog].

An artificial stenosis model consisting of a revolving centric cylinder with six boreholes (10-60% diameter reduction) was implanted in the superficial femoral artery of anaesthezised beagles (n = 10). Range gated pulsed Doppler signals were recorded at 7 sites between three diameters upstream to ten diameters downstream the Angle corrected parameters derived from the contour of spectral lines between 3 and 21dB on both sides of mode frequency were calculated for different time windows. Two groups of dogs could be distinguished. Group A showed marked downstream power spectrum changes which did not correlate to the degree of stenosis. In Group B, in contrast, the degree of power spectral disturbances correlated to the degree of stenosis. It was suggested that partial thrombosis of the stenoses during measurement provides an acceptable explanation for the missing correlation in Group A.

Animals↗
PubMed1991

[What does 31 phosphorus magnetic resonance spectroscopy measure?A validation in healthy probands].

With 31P nuclear magnetic resonance spectroscopy skeletal muscle metabolism can be measured noninvasively. Aim of this study was to investigate intraindividual reproducebility, interindividual variability, and the correlation of the NMR parameters PCr, alpha-, beta-, gamma-ATP to graded exercise. Reproducebility and variability of PCr values were comparabel to changes of the pH value. Alpha-, beta-, gamma-ATP did not change during measurements. Correlations between the workload and the changes of the NMR parameters were rare. It was found that the intraindividual reproducebility is low and the interindividual variability is high. No systematic correlation between the NMR parameters and the workload could be seen. The termination of exercise in healthy volunteers is not explained by energy depletion but due to other mechanisms. There is no evidence that 31P NMR spectroscopy presents remarkable advantages for clinical purposes compared to well established diagnostic methods.

Aged↗
PubMed1985

Drug-induced changes of the flow pulse contour recorded by directional CW-Doppler devices: a possible estimation of changes in vascular characteristic impedance and peripheral resistance.

Ultrasound Doppler sonography using directional continuous wave Doppler devices is an inexpensive, simple tool used worldwide for the diagnosis and hemodynamic assessment of patients with peripheral vascular disease (PVD). In addition to pressure evaluation, the interpretation of Doppler velocity pulses has become routine within the last years. However, spontaneous variations in characteristic impedance of muscular arteries or in peripheral resistance will lead to respective variations of arterial reflection coefficients, with consequent changes of the arterial flow pulse reflection pattern and flow pulse contour. The authors studied peripheral Doppler wave forms in 20 volunteers after buccal administration of 1.6 mg of glyceryl trinitrate (GTN) and i.a. (femoral) injection of 30 mg tolazoline hydrochloride. Velocity pulse changes due to artificially introduced variation in peripheral resistance (reactive hyperemia, total arterial blockade) were compared to those induced by above maneuvers. An isolated decrease in characteristic impedance of muscular arteries without alteration of the peripheral resistance is characterized by an increase in the amplitudes of foreward as well as the reverse flow phase of the Doppler signal, with predominant increase of the early diastolic reverse flow phase and subsequent decrease in mean velocity. In contrast, isolated changes in peripheral resistance are reflected mainly by subsequent variations of the reverse flow phase amplitude of the Doppler signals.

Adult↗
PubMedDate not supplied

A new rotational thrombectomy catheter: system design and first clinical experiences.

PURPOSE: To describe a new catheter for the percutaneous mechanical removal of fresh and organized thrombi, and to assess its efficacy and safety in vitro and in vivo. METHODS: The catheter consists of a coated stainless steel spiral that rotates at 40,000 rpm over a guidewire inside the whole length of an 8 Fr, single-lumen, polyurethane catheter, driving a dual-blade cutting crown. Abraded occlusion material is sucked into the catheter head through distal side holes and transported by the spiral into a reservoir at the proximal end. The efficacy of the device was tested in arterial models and fresh bovine carotid arteries (n = 72). In a clinical pilot study 10 patients (8 women, 2 men; mean age 70.6 +/- 10.1 years) with occlusions of the superficial femoral artery (2-12 cm, mean 5.8 cm), not older than 4 weeks, underwent thrombectomy with the new catheter. RESULTS: In arterial models and bovine cadaver arteries the catheter completely removed fresh thrombi. Occlusion material of higher consistency was cut into particles of 100-500 micron and transported outside. Thrombectomy was successful and vessel patency restored in all 10 patients. The ankle/brachial pressure index significantly (p < 0.0005) increased from 0.41 +/- 0. 18 before intervention to 0.88 +/- 0.15 after 48 hr and to 0.84 +/- 0.20 after 3 months. Two reocclusions occurred within 14 days after the intervention. CONCLUSION: Thrombectomy with the new device appears to be feasible and safe in patients with acute and subacute occlusions of the femoropopliteal artery.

Aged↗
PubMedDate not supplied

A 12-month, randomized, placebo-controlled trial of propentofylline (HWA 285) in patients with dementia according to DSM III-R. The European Propentofylline Study Group.

Alzheimer's disease (AD) and vascular dementia (VaD) share several features such as overactivation of microglial cells, damage induced by free radicals, glutamate and calcium overload. Propentofylline (HWA 285) has shown beneficial effects on all of these common elements, thus favouring its use in both subtypes of dementia. In a multinational, randomized, 12-month, double-blind, parallel-group study 260 out-patients with mild to moderate AD or VaD received 300 mg propentofylline (n = 129) or placebo (n = 131) three times daily 1 h before meals. The efficacy was tested at four independent rater levels (physician, psychologist, relative and patient) with assessments covering three major domains of dementia (global function, cognitive function and activities of daily living). After 12 months, the total patient population showed statistically significant treatment differences in favour of propentofylline for the global measures of dementia (Gottfries-Bråne-Steen scale, GBS, p = 0.001; Clinical Global Impressions, CGI, item I: p = 0.004, item II: p = 0.072) as well as for the cognitive measures (Syndrome Short Test, SKT, p = 0.002) and Mini-Mental State Examination (p = 0.001). The activities of daily living also showed a significant treatment difference in favour of propentofylline (p = 0.002). No significant treatment differences were found for rating scales performed by the patients. At month 12, VaD patients showed treatment differences in favour of propentofylline for the GBS total score (p = 0.006), CGI item I (p = 0.004), GGI item II (p = 0.044) and SKT (p = 0.028). Treatment differences for AD patients were all in favour of propentofylline and reached statistical significance for the SKT (p = 0.018). Propentofylline showed a good safety profile with respect to adverse events, vital signs, ECG and laboratory changes.

Activities of Daily Living↗
PubMedDate not supplied

Physiological flow variations in the periorbital arteries in Zambian Africans. A screening with bidirectional Doppler ultrasound.

Directional Doppler sonography with direct evaluation of the extracranial carotid artery system and scanning of the periorbital arteries has been performed in 49 black Zambian hypertensive patients and in 19 controls without cardiovascular risk factors. Direct evaluation of the extracranial carotid artery system did not show any abnormalities. In contrast to this periorbital Doppler examination revealed positive findings with retrograde flow direction in the supratrochlear artery in 19% and 21% of all examined carotids in the hypertension and control group, respectively. Compared to direct carotid angiography, 66% of the positive supratrochlear and 13% of the positive supraorbital findings in the hypertensive patient group could be shown to be false positive results. As a possible explanation of this high incidence of a retrograde flow direction in periorbital arteries a different flow physiology in the ophthalmic artery of black Zambians compared to Caucasians is discussed.

Adult↗