PubMed Health⌕ Search

Biomedical subjects

J Radtke

Publications and source records attributed to J Radtke.

At least 19 recordsLinked to original sources
PubMed2001

Ferrographic tracking of bacterial transport in the field at the narrow channel focus area, Oyster, VA.

The first results from an innovative bacterial tracking technique, ferrographic capture, applied to bacterial transport in groundwater are reported in this paper. Ferrographic capture was used to analyze samples during an October 1999 bacterial injection experiment at the Narrow Channel focus area of the South Oyster site, VA. Data obtained using this method showed that the timing of bacterial breakthrough was controlled by physical (hydraulic conductivity) heterogeneity in the vertical dimension as opposed to variation in sedimentsurface or aqueous chemical properties. Ferrographic tracking yielded results that compared well with results from other tracking techniques over a concentration range of 8 orders of magnitude and provided a low detection limit relative to most other bacterial tracking techniques. The low quantitation limit of this method (approximately 20 cells/mL) allowed observation of transport of an adhesion-deficient bacterium over distances greater than 20 m in the fine sand aquifer underlying this site.

Bacteria↗
PubMed2001

[Lip-jaw-palate clefts. Heterogenous disease pictures].

BACKGROUND: Orofacial clefts are congenital structural deficits involving the lip with or without the palate. The genetic origins of orofacial clefts have been considered as heterogeneous for a long time. Non-syndromatic clefts are based on complex traits. DISCUSSION: The different approaches towards the genetics of this multifactorial disease are discussed and the consequences for genetic counselling for patients, persons at risk and their relatives are reflected upon.

Adult↗
PubMed2000

Neoadjuvant, hyperfractionated irradiation induces apoptosis and decreases proliferation in squamous cell cancer of the oral cavity.

Twenty-eight patients with squamous cell carcinoma of the oral cavity were treated with a total dose of 20 Gy. Tissue samples for immunohistochemistry were taken at the time of diagnostic biopsy and at surgery after radiotherapy (RX). For detection of proliferating cells, the immunoperoxidase reaction with Ki67 was performed. Apoptotic cells were detected by the TdT-mediated biotin dUTP nick end labeling (TUNEL) method. RX reduced proliferation in 27 patients, only in one case did the proliferation index (PI) increase. Delta PI (PI before RX PI following RX) amounted to 4.11% (SD=3.2%; P<0.0001). The apoptotic index (AI) increased significantly subsequent to neoadjuvant RX. Delta AI (AI after RX--AI before RX) measured 1.82% (SD=0.9; P<0.001). These data indicate that RX of patients suffering from squamous cell carcinoma of the oral cavity with a dosis of 20 Gy induces apoptosis and inhibits proliferation of tumor cells.

Adult↗
PubMed1998

[Phenolic acid intake of adults in a Bavarian subgroup of the national food consumption survey].

Phenolic acids, essentially hydroxycinnamic acids and hydroxybenzoic acids, are secondary plant products and commonly found in plant derived foodstuff. The antioxidant and anticarcinogenic properties of phenolic acids could be one of the facts to explain the inverse association between fruit and vegetable intake and the incidence of coronary heart disease and cancer, respectively, as found in epidemiologic studies. Phenolic acids are rarely listed in food composition tables and there are no dietary intake data available. Consequently, a data base containing the phenolic acid content of foods (literatur data) was built and 7-d dietary protocols of 63 women and 56 men of a Bavarian subpopulation (age 19-49 years) of the German National Food Consumption Survey (NVS) were evaluated. The average phenolic acid intake of men and women is 222 mg/d within a large range. The dominating one within all the phenolic acids is clearly caffeic acid (206 mg/d); the intake of the other phenolic acids amounts to 0.2 (gentisic acid) up to 5.2 mg/d (ellagic acid). The sum of hydroxybenzoic acids and hydroxycinnamic acids amounts to 11 mg/d and 211 mg/d, respectively. Significant sex differences are found for some of the phenolic acids. Especially, the average intake of caffeic acid of women (229 mg/d) is higher than that of men (179 mg/d) caused by the high amount of coffee consumption. The age group "25-49 years" is consuming more coffee than the age group "19-24 years" and, therefore, reveals a significantly higher intake of caffeic acid. The major sources of phenolic acids are coffee with 92% of the caffeic acid intake and fruits (including fruit products and juices) with 75% of the salycilic acid and 59% of the p-coumaric acid intake. Consequently, phenolic acids are consumed in considerable amounts with food. Since antioxidant and anticarcinogenic properties of phenolic acids are already proven in in vitro as well as in animal experiments, epidemiologic studies will show whether a high phenolic acid intake goes ahead with a reduced risk for coronary heart disease or cancer in humans.

Acids, Carbocyclic↗
PubMed1997

[Flavonoid intake of adults in a Bavarian subgroup of the national food consumption survey].

Flavonoids as naturally occurring compounds of plant derived foodstuff reveal some biological effects (antioxidative, antimutagenic, anticarcinogenic) which makes them interesting substances in the prevention of atherosclerosis and cancer in humans. Data on the flavonoid content of food are not considered in food composition tables, and human intake data are scarce (flavonols) or missing. Consequently, after installing a flavonoid data base by means of literature data, 7-d dietary protocols of 119 adults (63 women and 56 men, age 19-49 years) representing a bavarian subgroup of the German National Food Consumption Survey (NVS) were evaluated. In all subjects, average intake of all flavonoids (calculated as aglycons) amounts to 54.0 mg/d (median) with a great range of variability. The most important flavonoid groups are flavonols (12.0 mg/d), catechins (8.3 mg/d), and flavanons (13.2 mg/d), followed by anthocyanidins (2.7 mg/d), proanthocyanins (3.7 mg/d) and phloretin (dihydrochalcone) (0.7 mg/d). Sex differences did not reach statistical significance. Fruits, fruit products and fruit juices were the most important flavonoid sources. Vegetables and its products provided about half of the flavonol intake. Therefore, statistically significant correlations (p < 0.001) exist between total flavonoid intake and the intake of vitamin C (r = 0.59) or dietary fiber (r = 0.49). Compared to other countries, flavonol intake of the investigated group of persons is rather low. With the built data base it was possible for the first time to calculate the intake of further flavonoids besides flavonols. In comparison to the intake of other antioxidants (e.g. vitamins C and E) the amount of flavonoids in the diet is considerably high and therefore should be regarded in further investigations on the role of diet in certain diseases.

Adult↗
PubMed1996

[Thermographic quantification of sensory and sympathetic nerve lesions in mandibular fractures--a prognostic criterium?].

As a rule, damage to segmental afferent nerves by trauma is accompanied with local impairment of sympathic functions. Standardized quantification of subjective items concerning the deficit of sensibility is quite problematical. Investigation by electrophysiological means yield not more than qualitative issues. In contrast, changes of sympathetic status and reaction of dependent dermatomas are quantitatively measurable by thermography. -26 patients with unilateral mandibular fractures complained of different posttraumatic or postoperative sensible impairment of the third branch of the trigeminal nerve. In the course of onto 3 years area and quality of the concerned neural defect were correlated to skin temperature that was measured by contact thermography and compared to the opposite reference region.- In all cases the early posttraumatic period showed a difference in temperature of the corresponding skin areas (delta T = 0.43 +/- 0.24 C). In 20 of 26 cases a relation between the changes of temperature concerning time and area and the sensible improvement could be seen. There was an individual time-lag between these developments. Side-comparing thermography was able to forecast improvement in 17 of 26 cases. Thus, the issued device provides statements about the amount and the course of posttraumatic loss of sensibility.

Follow-Up Studies↗
PubMed1994

[Ultrasonic guided cannulation of the axillary vein in intensive care patients].

Cannulation of the axillary vein is claimed to be an effective and relatively safe access to the central venous (CV) system [2, 4, 5, 8]. However, anatomical landmarks recommended for venous location (Muskulus pectoralis minor, processus coracoideus) are probably hard to identify in the majority of intensive care (ICU) patients. This investigation evaluated unidirectional 8 MHz Doppler ultrasound (US) in locating the axillary vein. Success rates and complications of this CV access in ICU patients is analysed. METHODS. The experimental design was approved by the local ethical committee (RUB). In 50 patients from our ICU cannulation of the axillary vein was attempted; all were in need of a CV line. Other CV puncture sites (except for the subclavian vein) were associated with contraindications. Patients were placed in a 15 degrees Trendelenburg position (15 exceptions); the arm was abducted to 45 degrees [5, 8]. The course of the axillary vein was located by Doppler US and marked on the skin with a felt pen. Prior to puncture, US intensity was judged by a score ranging from 0 to 4. After skin desinfection, sterile draping, and local anaesthesia, puncture of the axillary vein was attempted. The puncture kit LeaderCath 11,515 (Vygon, Aachen, FRG) was used. When venous blood could be aspirated, the Seldinger guidewire was inserted and the definite catheter placed. The experimental design allowed up to ten punctures, slightly modified in angle and direction of the needle, if puncture of the axillary vein or guide-wire placement failed. The cannulation attempt was classified as unsuccessful in the following cases: malposition, axillary vein not encountered by the puncture needle, guide-wire placement unsuccessful, or if identification and cannulation of the vein lasted more than 20 min. The puncture attempts were evaluated in respect to success rate, time, relation of US intensity to puncture attempts and CV pressure, complications, and malposition. RESULTS. Of the 50 attempted CV catheters, 43 were placed successfully. In 2 cases the axillary vein could not be encountered by the puncture needle. Guide-wire placement did not succeed in 4 patients. One catheter was malpositioned in the ipsilateral internal jugular vein. Four inadvertent punctures of the axillary artery remained without sequelae after compression. No further puncture-related complications were observed. With high US intensity score the number of puncture attempts necessary for successful vein cannulation was lower. On the other hand, complications and puncture failure seemed to be more frequent in patients with lower US intensity scores. DISCUSSION. CV access via the axillary vein had a satisfying success rate (43/50) and proved to be a safe procedure in our ICU patients despite higher risk factors compared to a healthy population. Although ethical reasons did not allow a randomised comparison with the standard technique, location of the axillary vein by Doppler US is likely to improve cannulation results and reduce complications induced by "blind" needle probing. With a low US intensity score, the rate of successful punctures is lower and complication rates increase. In some patients, e.g., those with extended tumour operations involving the head and neck, CV access via the axillary vein may be of high clinical value.

Axillary Vein↗
PubMed1994

Sister chromatid exchange frequencies in lymphocytes of oral cancer patients seem to be influenced by drinking habits.

Sister chromatid exchange (SCE) values were determined in the lymphocytes of 24 oral cancer patients before therapy and in the lymphocytes of 24 control persons standardized with respect to sex, age and smoking habits. Oral cancer patients showed significantly elevated SCE values (mean 7.82 versus 6.42). In both groups the highest SCE values were found in the subgroups with the highest alcohol consumption. A significant correlation between SCE and gamma-glutamyltranspeptidase (GGT) values by Spearman correlation analysis was detected in the combined group (cancer patients and control persons) (n = 32, r = 0.40, P = 0.023). The SCE values in the oral cancer patients were weakly correlated (Pearson) to DNA adduct levels (n = 22, r = 0.39, P = 0.068) and DNA single-strand breakage frequencies (n = 12, r = 0.56, P = 0.054) in lymphocytes. The correlation (Pearson) between SCE values and DNA strand breakage values in lymphocytes was significant (n = 10, r = 0.67, P = 0.036) in smoking cancer patients. The increase of SCE values with respect to alcohol drinking habits underlines epidemiologic findings that alcohol is an important co-carcinogen in many cancers, especially in oral cancers. Because of the influences on SCE and adduct levels in lymphocytes, alcohol drinking habits should be controlled as broadly as possible in biomarker studies.

Adult↗
PubMed1993

DNA strand breakage and DNA adducts in lymphocytes of oral cancer patients.

In lymphocytes of 12 oral cancer patients (and two control groups) the frequencies of DNA single-strand breaks and DNA-protein cross-linking were determined by alkaline filter elution. We found elevated DNA elution rates, which must be interpreted as an increased strand breakage frequency. There were significant correlations between the DNA strand breakage frequency and smoking habits. Using the 32P-postlabelling assay we determined the DNA adduct level in lymphocytes of 23 oral cancer patients (and two control groups). No significant influence of smoking habit on the DNA adduct level could be detected. There was a significant correlation between the DNA adduct level and the gamma-glutamyltranspeptidase (GGT) value, suggesting systemic influences of alcohol drinking habits on the adduct level.

Adult↗
PubMed1991

A set of 4 nuclear proteins binds to a DNA sequence within the FOS promoter region.

We investigated DNA-protein-interactions occurring in the promoter region of c-fos using two-dimensional electrophoresis and south-western-blotting. When nuclear extracts from the human glioblastoma cell line HeRoSV were tested for their DNA-binding behaviour to a 650 bp-fragment within the promoter region of c-fos, we found 4 proteins designated as 120/6.6, 75/5.4, 65/6.4 55/5.0 interacting with this fragment. An additional protein 60/6.0 was detected by using a digoxygenine-labelled probe. These observations let us to assume that beside the well characterized SRF and FOS-JUN proteins additional factors recognize the promoter sequence and may play a role in c-fos regulation.

Base Sequence↗
PubMed1991

Exon-intron structure and nucleotide sequence of the rat proacrosin gene.

The nucleotide sequence and exon-intron organization of the proacrosin gene was determined. It consists of 6 exons and 5 introns of which one is located in the 5' untranslated region. The transcription initiation site was determined at position 471 (564 nucleotides upstream of ATG), TATA- and TAAT-boxes were found 588 and 656 bp upstream of the ATG-translation start point, respectively.

Acrosin↗