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Biomedical subjects

W Krüger

Publications and source records attributed to W Krüger.

At least 19 recordsLinked to original sources
PubMed1992

Laser Doppler flux and tissue oxygenation of experimental tumours upon local hyperthermia and/or hyperglycaemia.

Laser Doppler fluxmetry and oxygen partial pressure (pO2) histography have been applied to investigate the acute effects of hyperthermia (HT) and/or hyperglycaemia (HG) on microcirculatory function and tissue oxygenation of subcutaneous rat tumours growing on the dorsum of the hind foot. The experiments were performed to test whether, and to what extent, the two adjunct treatment modalities applied alone or in combination can modify these therapeutically relevant parameters. Local HT was performed in a saline bath (44 degrees C) for 2 h; HG was induced by i.v. infusion of 40% glucose solution for 2.5 h (blood glucose levels: 35-40 mM during heating). Laser Doppler flux (LDF) in superficial tumour tissue regions was recorded over the entire treatment period; tumour pO2 distribution was evaluated immediately after termination of the treatment. HG alone reduced the average LDF signal to 18% of the baseline reading before treatment, but did not influence the tumour oxygenation status and the proportion of pO2 readings occurring in the radiobiologically hypoxic class (pO2 = O-2.5 mm Hg). This phenomenon is most probably due to the occurrence of the Crabtree effect (reduction of the O2 consumption rate when excess glucose is available within a malignant tumour). Hyperthermia alone reduced LDF to approximately the same extent, and led to a rise in the number of pO2 readings in the hypoxic range with only minor changes in the average pO2. The combined treatment (HT/HG) neither increased the fraction of "hypoxic" pO2 readings nor intensified the flow drop already present at the end of the tumour heating. It is thus concluded that under hyperglycaemia the oxygenation status of normothermic and heated tumours is maintained. It may therefore be hypothesized that hyperthermia in conjunction with hyperglycaemia might be a better "radiosensitizer" than hyperthermia alone.

Animals↗
PubMed1992

[Prevalence of hepatitis C virus in poly-transfused patients with hematologic and oncologic diseases].

Patients with hematological and oncological diseases often require intensive, supportive hematotherapy due to the underlying disease or chemo-/radiotherapy. As a consequence, they had an increased transfusion-associated risk of hepatitis C virus infections (non-A, non-B-posttransfusion hepatitis) until 1989-1990, when specific and sensitive HCV antibody tests became available. This is confirmed by our study of 'first' and 'second' generation (1.0 and 2.0) anti-HCV EIAs against structural and non-structural (NS) antigen-determinants. Ten of 101 patients (10.9%) were anti-HCV positive in 2.0 tests. HCV antibodies were detected more often by 2.0 EIAs and the new HCV-immunoblot (4-RIBA), than by 1.0 EIAs. In this respect, the patients' serological HCV profile differs from that of healthy blood donors, which display a prevalence of NS-antibodies.

Adolescent↗
PubMed1992

Water-filtered infrared-A radiation: a novel technique to heat superficial tumors.

A novel device consisting of an infrared-A (= ultrared-A) radiation source equipped with a water filter in the radiation path is described which allows for the therapeutic heating of superficial experimental and human tumors. Preliminary studies with agar phantoms showed that heating in the presence of the water-cuvette avoids intolerable overheating in the very superficial layers. This effect can be further enhanced by surface cooling with room air such that a stratification of the temperature distribution can be achieved. In subsequent experiments, temperature distributions were recorded in the x-, y- and z-axis of superficial rodent tumors. The results obtained confirm those from the phantom experiments, showing that therapeutically relevant temperatures (T > or = 42 degrees C) could be achieved through the tumor mass to a depth of approximately 1.2 cm. Temperature homogeneity is comparable to that seen in superficial tumors undergoing water-bath hyperthermia. This novel technique has proved to be reliable, is well-tolerated, is easy to apply, and is easily accessible to a larger number of potential users for the local heating of superficial malignancies.

Agar↗
PubMed1991

Acute changes of systemic parameters in tumour-bearing rats, and of tumour glucose, lactate, and ATP levels upon local hyperthermia and/or hyperglycaemia.

Arterial blood pressure and relevant parameters of the arterial blood (O2 and CO2 tensions, pH, haematocrit, serum electrolytes and osmolality) were determined in tumour-bearing rats upon local hyperthermia (HT) and/or hyperglycaemia (HG). Tumour heating was performed in a saline bath (44 degrees C) for 120 min; hyperglycaemia was induced by i.v. infusion of 40% glucose solution for 150 min [blood glucose levels: 35-40 mM during heating; total amount of glucose: 1.19 g/100 g body wt.; infusion rates: 0.31 ml (100 g body wt.)-1 min-1 for 2 min, 0.02 ml (100 g body wt.)-1 min-1 for 88 min, and 0.01 ml (100 g body wt.)-1 min-1 for 60 min]. Immediately after treatment, glucose, lactate and ATP levels were determined in tumour and muscle specimens and compared to these values under normothermic (NT) and/or normoglycaemic (NG) conditions. In all groups (NT/NG, NT/HG, HT/NG, HT/HG) there were only minor but characteristic changes in blood parameters, which were mainly due to the volume and type of the infused fluids (glucose solution, saline). During hyperglycaemia, tumour glucose levels rose 13- to 17-fold, whereas muscle glucose concentrations exhibited only a 3- to 5-fold increase; lactate levels were 1.9-2.5 times higher in tumours than in muscle, indicating an increase in the metabolic differences between normal and malignant tissues. Despite an increased glucose availability, tumours did not show an improved energy status and, thus, would not be expected to develop a decrease in thermal sensitivity or stimulation in growth rate. The good systemic tolerability of the combined treatment (HT/HG) and the differential changes in malignant and normal tissue occurring under these conditions, support further attempts to manipulate tumour metabolic environment by glucose in order to achieve better therapeutic results.

Adenosine Triphosphate↗
PubMed1991

Polymyalgia rheumatica and rheumatoid arthritis of the elderly: a clinical, laboratory, and scintigraphic comparison.

Clinical, laboratory, and scintigraphic features of 16 patients with polymyalgia rheumatica and 23 patients matched for age presenting with classical or definite rheumatoid arthritis (American Rheumatism Association 1958 criteria) of the elderly were compared in order to define features that might distinguish between these two syndromes. The sensitivity of proposed diagnostic criteria for polymyalgia rheumatica was always higher in the group with polymyalgia rheumatica, though only significantly so for morning stiffness. A comparison of 27 different laboratory features showed few significant differences between the diseases, though correlation between laboratory variables within each of the disease groups differed, perhaps suggesting a fundamental pathogenetic difference between them. Scintigraphy of the shoulder joint proved of no value in differential diagnosis. It was concluded that polymyalgia rheumatica and rheumatoid arthritis of the elderly are probably discrete clinical entities. Bilateral upper arm tenderness, lack of positive rheumatoid factor, and a normal caeruloplasmin are the most valuable features for distinguishing polymyalgia rheumatica from rheumatoid arthritis of the elderly.

Aged↗
PubMed1991

[Comparative studies of toothpastes and toothpaste ingredients in biological systems: 1. Can various toothpastes be differentiated by relative biological effectiveness in cell culture studies?].

The cytotoxicity of 15 commercial toothpastes was examined in human epithelial cell cultures. The following parameters were evaluated: protein concentration, DNA-synthesis, cell morphology and autoradiography. In comparison to the control cell culture, one toothpaste had no influence on the cell growth at all. The other pastes caused a more or less strong growth inhibition, which also depended on the concentration of the toothpaste suspension. The presented investigations showed that the cytotoxicity tests applied to toothpastes yielded a good validity.

Cells, Cultured↗
PubMed1991

[Need for preventive dentistry in adult women: investigation in maternal convalescent homes. 2. Tooth and periodontal findings].

For this study an extensive oral examination was performed in 111 women between 21 and 48 years of age recreating themselves in special rest homes. A mean DMF-T of 19.1 and a mean DMF-S of 62.5 was found; women with a low education (Sonderschule) showed an especially high DMF-S of 85.0, participants with a secondary education (Abitur) had a DMF-S-Index less by half. The oral hygiene of the women was insufficient (mean QHI 2.6), papilla bleeding was easy to provoke in most of them. 98% of the women needed periodontal treatment, 10.8% showed a probing depth of 6-8 mm. 60.8% of 942 examined restorations needed to be renewed, the reason was mostly marginal leakage.

Adult↗
PubMed1991

[Comparative studies of toothpastes and toothpaste ingredients in biological systems. 2. Study of toothpaste ingredients and their effects on cell growth].

The influence on cell growth by different ingredients of toothpastes was examined in cell culture. Following parameters were evaluated: protein concentration, MTT-test and cell morphology. Substantial inhibition of cell growth was caused by tensides. Preparations with Tego-Betain had a significantly less influence on cell growth than Texapon. Other ingredients as medical soap, fluoride and preservative showed a very low effect.

Animals↗
PubMed1991

[Need for dental prophylaxis in grown women: an investigation in maternal rest centers. 1. Information knowledge and or oral hygiene status].

111 women out of 316 women relaxing in three rest homes volunteered to participate in this study and answered a questionnaire concerning following subjects: daily oral hygiene, knowledge in hygiene procedures, frequency of dental treatment and interest in dental prophylaxis. Oral hygiene behaviour and knowledge were not sufficient. Only half of them knew dental floss and fluorides. Interdental care was practised by 20 women and only 10 used fluorides, they had without exception a secondary education. Most of the participants were educated in dental health care mainly by their parents. 36 women went to see the dentist only in case of necessity. 15 women were very afraid of dental treatment. 60% out of 111 women participated in a lecture on preventive dentistry and prophylaxis.

Adult↗
PubMed1990

[Comparative investigations of new dental electrosurgical instruments].

11 electrosurgical units of several manufactures were analysed by physical measurements. Conventional units and those with constant output voltage demonstrate nearly identical behavior in their voltage- and power-characteristics at load-impedance occurring during dental electrosurgery. So far there are no advantages of simple voltage control. We did not find technical deficiencies concerning security in the modern units examined.

Electrosurgery↗
PubMed1990

[A responsibility key for personnel in health and social service as an aid for occupational medicine epidemiology].

Staff members of the public health service were examined referring to problems of industrial epidemiology. This examination requires the consideration of activity and branch of study of the people involved. A system of itemization used for encoding is explained. Results of application are introduced with occupationally caused allergy to formaldehyde serving as example. In addition, further possibilities of application are shown.

Cross-Sectional Studies↗
PubMed1990

[Results of physiologic occupational studies of intensive care unit nurses].

Continuous measures of the pulse by wireless telemeter to value the degree of work were performed by 6 nurses in intensive care unit during work in shifts about 476 hours. Work activity and time were registed simultaneously. In the outcome is ascertained that the work of these nurses is middle heavy on an average with heavy or very heavy short portions. To reduce or to avoid the latter proposals are recommended.

Adult↗