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Biomedical subjects

H P Albrecht

Publications and source records attributed to H P Albrecht.

At least 19 recordsLinked to original sources
PubMed1995

[Disordered cutaneous microcirculation in diabetic neuropathic foot ulcer. Is modification by retrograde transvenous perfusion therapy possible?].

Due to the high risk of amputation they involve, diabetic neuropathic plantar ulcers (DNPU) must be regarded as a late manifestation/complication of diabetes mellitus. The suspected cause of these ulcers--disturbed cutaneous microcirculation--was studied by simultaneously measuring laser-Doppler flux (LDF) and cutaneous oxygen tension (pCUO2) in 14 patients with DNPU at three differently affected sites (dorsal forefoot, ulcer edge, lower leg). Dynamic tests (arterial occlusion, local hyperthermia) as a measure of vascular reactivity showed significantly reduced pCUO2 parameters coinciding with elevated LDF values. This reflects a shift of blood flow from the nutritive capillaries towards deeper vessels. Abolition of normal vasoconstriction in the arteriovenous shunt vessels by diabetic polyneuropathy is the assumed cause of increased AV perfusion, with a consequent rise in LDF values. In a subgroup of the above patients (n = 7) undergoing daily intravenous retrograde perfusion therapy (RVP) over 10 days several basic and dynamic microcirculatory functions were studied before and after this treatment. This subgroup showed on the forefoot and the lower leg a remarkable improvement of the microcirculatory parameters investigated, suggesting a better oxygen supply to the tissues after RVP therapy.

Adult↗
PubMed1995

[Color-coded duplex ultrasound and laser Doppler flowmetry of finger tips of healthy probands].

In the study presented, color-coded duplex sonography (CCDS) and laser Doppler flux (LDF) signals from finger tips of 7 healthy individuals were recorded simultaneously. The aim of the study was to examine whether or not the results of a functional test ('deep inspiration') could also be observed with an ultrasonic Doppler. In the literature this test is known to provoke notable blood flow characteristics of the LDF ('inspiratory gasp'), a phenomenon which is caused by a sympathetically mediated vasoconstriction of acral vessels. With regard to the penetration depth of the LDF in skin it was of further interest to determine the distance between the surface of the skin and the vessels found near the surface. We found for CCDS parameters (color pixels/image; time-averaged flow velocity [TAV]; resistance index [RI]) as well as for LDF (flux [taLDF]) significant changes before versus after 'deep inspiration'. CCDS is a new diagnostic tool to visualize also very small vessels down to 0.2 mm, e.g. in finger tips. It should be evaluated which role this method may play in combination with functional tests in diagnostic handling, e.g. of patients with polyneuropathies or collagenoses.

Adolescent↗
PubMed1995

[Dynamic function tests for detection of physiologic and pathophysiologic reactions in cutaneous microcirculation].

Functional tests simulating local stresses are especially suitable for the evaluation of physiological and pathophysiological patterns in the cutaneous microcirculation, particularly if combined with non-invasive methods such as laser-Doppler fluxmetry and oxygen tension measurements. Arterial occlusion (3 min) and local heating (up to 42 degrees C) are appropriate as stimuli to simulate specific local demands on the cutaneous perfusion similar to those produced by pressure, myokinesis, heat, and inflammation. When the current microcirculatory status is described the initial values (LDF and pO2) and their time-courses during each functional test can be used to determine the so-called post-stimulatory parameters. These-- corresponding to physiological equivalents--allow statements on the vascular reactivity towards hypoxia and ischaemia. Furthermore, dynamic performance parameters can easily be derived from the poststimulatory values. They describe the capacity of cutaneous microcirculation with regard to perfusion reserves and ischaemic tolerance in local stress situations in an appropriate manner. As an example of the usefulness of functional tests for cutaneous microcirculation, the physiological and pathophysiological patterns found in systemic sclerosis are described.

Blood Flow Velocity↗
PubMed1994

[Idiopathic pustular and bullous variants of Sweet syndrome].

We report on the case of a 62-year-old patient with disseminated pustular plaques affecting especially his face and hands. These lesions exhibited severe blistering later in the course. The diagnosis of an unusual variant of an acute febrile neutrophilic dermatosis (Sweet's syndrome) was histologically confirmed. Pustular lesions are known to occur in Sweet's syndrome. Secondary development into bullous lesions, however, has not previously been described. No associated disease has so far been detected.

Biopsy↗
PubMed1994

[Initial visceral involvement with diffuse systemic scleroderma].

Progressive systemic sclerosis (PSS) is characterized in most patients by initially unspecific symptoms like acrocyanosis. Raynaud's phenomenon, general malaise or acral paresthesia. Clinical manifestations appear with an edematous-inflammatory stage of disease leading to a chronic-progressive phase with increasing fibrosclerosis of the skin and internal organs. Dermal involvement and the demonstration of immunopathological abnormalities in the peripheral blood precede visceral fibrosis in most cases. We report on an unusual case of diffuse PSS with preceding involvement of internal organs. Early visceral fibrosis is demonstrated by histomorphological results and is correlated with laboratory findings. Serum antinuclear antibodies could not be obtained until 4 months ante finem and the liver was also involved in the fibrotic process.

Antibodies, Antinuclear↗
PubMed1994

Disturbances of cutaneous microcirculation in patients with diabetic legs: additional parameters for a new therapeutic concept?

To study disturbed microcirculation involved in the pathogenesis of diabetic neuropathic plantar ulcers (DNPU), we recorded dynamic changes in laser-Doppler flux (LDF) and cutaneous oxygen tension (pcuO2) caused by short-time arterial occlusion and local heating at three different sites (forefoot, ulcer edge, lower leg) in patients (n = 14) with DNPU and healthy controls (n = 18). Significantly reduced dynamic pcuO2 parameters coincided with a significant increase of flux in the patient group. This post-stimulatory "hypoxic hyperemia" indicates a shifting of blood flux, reducing circulation of the nutritive capillaries comparable to an internal "steal effect". This may predispose to the development of DNPU when additional stresses influence the initial borderline balance, characterized by similar pcuO2 and increased flux values compared to controls. Abolishment of normal vasoconstriction in the shunt vessels by diabetic polyneuropathy is the assumed cause of increased arteriovenous perfusion and therefore raised flux values. Non-invasive testing of microcirculatory functions demonstrates characteristic disturbances in DNPU patients and could be used as additional parameters for new therapeutic concepts as the intravenous retrograde perfusion (RVP). After RVP therapy, applied to a subgroup (n = 7) of the patients, some dynamic microcirculatory parameters improved, allowing a preliminary quantitative evaluation of a therapeutic regimen.

Adult↗
PubMed1994

[Respiration-dependence of cutaneous laser Doppler flow motion].

The aim of this study was to show and to quantify the breath-dependency of cutaneous fluxmotion in the volar proximal forearm using a new computer-aided system. A meanflux-related index (MI) representing the intensity of the influence of respiration on fluxmotion was calculated. There was a good correlation between MI and the rate of respiration under spontaneous breathing: the lower the rate of respiration, the higher the value of MI. Prescribing a constant breathing rhythm amplifies this frequency-dependent effect. According to occurrence of low rates of respiration (< 12/min) also under physiological conditions the respiration should be simultaneously recorded while assessing fluxmotion.

Adolescent↗
PubMed1992

[A special form of Bazex acrokeratosis in small cell bronchial cancer].

A 66-year-old pensioner developed distinct, erythematosquamous and keratonic lesions on the hands and feet within 2 months, and also a progressive red-bluish discoloration of the whole integument. Clinical and X-ray exploration revealed a still asymptomatic small-cell bronchial carcinoma, so that the otherwise inexplicable skin lesions made an acrokeratotic paraneoplastic syndrome of the Bazex type seem most likely. This very rare syndrome has hitherto been observed only in patients with carcinomas of either the bronchial or the upper digestive tract, with or without cervical and mediastinal lymph node metastases. We report on our third patient with Bazex-type acrokeratosis, mainly because of the uncommon distribution and severity of his otherwise typical lesions. In addition, recent reports on this syndrome in the literature are reviewed.

Acrodermatitis↗
PubMed1991

L-dopa potentiating analogs of Pro-Leu-Gly-NH2 with oral efficacy.

Chemical modification of PLG, comprising replacement of proline or/and leucine by unnatural amino acids led to analogs with high oral efficacy. The most active analog identified in the course of our works was 1-prolyl-2-phenyl-1-2-aminobutanoylglycinamide (Doreptide). Doreptide is presently further evaluated as a new drug for the treatment of Parkinson's disease.

Administration, Oral↗
PubMed1990

[Noninvasive intraoperative measurement of intracapillary hemoglobin oxygenation and relative hemoglobin concentration in surgical skin flaps].

We describe the Erlangen microconducting spectrometer (EMPHO I), a device that measures the oxygen saturation and relative haemogloblin content in the capillaries. These factors determine the oxygen supply and survival of cutaneous flaps. The EMPHO I was used for intraoperative measurements in pectoralis major myocutaneous flaps and showed reproducible results, so that it is valid for intraoperative monitoring in plastic surgery.

Computer Graphics↗
PubMed1989

Measurements of angular distributions of Rayleigh and Mie scattering events in biological models.

Remission spectroscopy in living tissues can only be performed because scattering processes induce a pronounced amount of backscattered light. New types of scattering chambers were constructed in order to investigate the angular distribution of light intensities caused by scattering events typical for living tissues. Different solutions and suspensions containing microspheres, haemoglobin molecules, erythrocytes and liver homogenate were used in order to gain basic information applicable to remission spectrophotometry in tissue. Reflection spectroscopy in biological tissues is only possible because of the scattering properties of the material under observation. Light which penetrates the sample is remitted from the tissue. The remission is caused by the scattering of the light by different biological structures and particles. This scattered light gives information about the optical properties of the particles and structures in an integral form. A scattering chamber for small sample volumes has been developed for measurements of the optical properties of various particles in suspension. Measurements of scattering diagrams from microspheres with an average diameter of 7 microns, artificial particles, haemoglobin solutions, mixtures of microspheres and haemoglobin as well as erythrocytes and mitochondria have been performed. The different optical behaviour of the measured signals is qualitatively discussed.

Erythrocytes↗