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Biomedical subjects

H Roos

Publications and source records attributed to H Roos.

At least 19 recordsLinked to original sources
PubMed2005

Chromosomal aberrations in peripheral lymphocytes of patients treated with radium-224 for ankylosing spondylitis.

The aim of this study was to investigate the in vivo frequency of chromosomal aberrations (primarily dicentric chromosomes and chromatid breaks) potentially induced by (224)Ra alpha-radiation in peripheral lymphocytes. The study was designed to serve as a cytogenetic analysis along with the therapeutic procedure of ankylosing spondylitis patients who were undergoing a treatment with (224)Ra-chloride. The total administered activity was 10 MBq, and the treatment followed a schedule of 10 i.v. injections per week, each with a dose of 1 MBq of (224)Ra. The calculation of absorbed doses delivered to the blood used the models suggested by the ICRP and yielded a value of 4.7 mGy/MBq. The frequency of chromosomal aberrations observed during the course of therapy was related to the blood dose. The frequency of dicentric chromosomes induced in vivo was found to agree well with the corresponding value of dicentrics induced in vitro. However--given that peripheral lymphocytes are in the cell cycle's G(0) stage--an unexpected increase with dose in the yield of chromatid breaks was observed, with about 95% of them occurring in cells without any other chromosome-type aberrations. Reasons for the production of chromatid breaks are discussed.

Adult↗
PubMed2005

[Principles of construction in the forepaw and hindpaw of the domestic cat (Felis catus). 4. Innervation of muscles and analysis of locomotion].

Principles of construction in the forepaw and hindpaw of the domestic cat (Felis catus). 4. Innervation of muscles and analysis of locomotion.The innervation relations of the fore- and hindlimb of the cat were newly investigated to complete the interpretation of the muscle innervation (Figs 1-4). By means of special motion studies the contribution of paw muscles was determined during balance, locomotion as well as under specific manipulation of the prevailing single phases of the motion cycle. The functional considerations are graphically prepared in Figs 5-11.

Animals↗
PubMed2004

High prevalence of knee osteoarthritis, pain, and functional limitations in female soccer players twelve years after anterior cruciate ligament injury.

OBJECTIVE: To determine the prevalence of radiographic knee osteoarthritis (OA) as well as knee-related symptoms and functional limitations in female soccer players 12 years after an anterior cruciate ligament (ACL) injury. METHODS: Female soccer players who sustained an ACL injury 12 years earlier were examined with standardized weight-bearing knee radiography and 2 self-administered patient questionnaires, the Knee Injury and Osteoarthritis Outcome Score questionnaire and the Short Form 36-item health survey. Joint space narrowing and osteophytes were graded according to the radiographic atlas of the Osteoarthritis Research Society International. The cutoff value to define radiographic knee OA approximated a Kellgren/Lawrence grade of 2. RESULTS: Of the available cohort of 103 female soccer players, 84 (82%) answered the questionnaires and 67 (65%) consented to undergo knee radiography. The mean age at assessment was 31 years (range 26-40 years) and mean body mass index was 23 kg/m2 (range 18-40 kg/m2). Fifty-five women (82%) had radiographic changes in their index knee, and 34 (51%) fulfilled the criterion for radiographic knee OA. Of the subjects answering the questionnaires, 63 (75%) reported having symptoms affecting their knee-related quality of life, and 28 (42%) were considered to have symptomatic radiographic knee OA. Slightly more than 60% of the players had undergone reconstructive surgery of the ACL. Using multivariate analyses, surgical reconstruction was found to have no significant influence on knee symptoms. CONCLUSION: A very high prevalence of radiographic knee OA, pain, and functional limitations was observed in young women who sustained an ACL tear during soccer play 12 years earlier. These findings constitute a strong rationale to direct increased efforts toward prevention and better treatment of knee injury.

Adult↗
PubMed2004

Exposure of aircraft crew to cosmic radiation: on-board intercomparison of various dosemeters.

Owing to their professional activity, flight crews may receive a dose of some millisieverts within a year; airline passengers may also be concerned. The effective dose is to be estimated using various experimental and calculation tools. The European project DOSMAX (Dosimetry of Aircrew Exposure during Solar Maximum) was initiated in 2000 extending to 2004 to complete studies over the current solar cycle during the solar maximum phase. To compare various dosemeters in real conditions simultaneously in the same radiation field, an intercomparison was organised aboard a Paris-Tokyo round-trip flight. Both passive and active detectors were used. Good agreement was observed for instruments determining the different components of the radiation field; the mean ambient dose equivalent for the round trip was 129 +/- 10 microSv. The agreement of values obtained for the total dose obtained by measurements and by calculations is very satisfying.

Aircraft↗
PubMed2004

[The blood vessels of the mesonephros of domestic cattle (Bos taurus), a corrosion cast study].

The blood vessels of the bovine mesonephros - a corrosion cast study Using scanning electron microscopy plastoid corrosion cast specimens of the mesonephros of 30-45-day-old bovine foetuses were investigated. The studies showed that the blood vessels of the mesonephros are organized in two separate networks similar to these of the teleosts and amphibians. The glomerula mesonephrica originate from the aorta implying that they belong to the high pressure system. The tubuli mesonephrici are surrounded by a filamentous independent capillary network which is shown for the first time in these studies. This capillary network originates from the caudal cardinal veins and represents a mesonephric portal system with a relatively low blood pressure. The blood from the two capillary networks diverts into terminal veins and into the subcardinal veins. The questions of haemodynamics in the mesonephros are discussed.

Animals↗
PubMed2004

The effect of centrifugal force on mRNA levels of collagenase, collagen type-I, tissue inhibitors of metalloproteinases and beta-actin in cultured human periodontal ligament fibroblasts.

BACKGROUND: The aim of orthodontic treatment is to relocate teeth abnormally positioned in the jaws. This is achieved by application of continuous force on the tooth, which is immediately being sensed by the periodontal ligament (PDL), bone and the gingiva. Since the bony response is mediated by the PDL, tooth movement is primarily a PDL phenomenon. OBJECTIVES: Thus, the purpose of the present study was to evaluate the direct effect of force (excluding the in vivo tissue response) on the molecular level of matrix metalloproteinase-1 (MMP-1) and collagen type-I (Col-I) in human PDL fibroblasts. METHODS: PDL cell culture flasks were centrifuged for 10, 20, 30, 60, 90 and 120 min by horizontal microplate rotor. The effect of force on mRNA levels of beta-actin, MMP-1, Col-I, tissue inhibitors-1 and -2 (TIMPs) genes was analyzed by RT-PCR. RESULTS: The results showed that force had no effect on the mRNA levels of beta-actin during the first 90 min of application of force, indicating for the first time the use of beta-actin gene as an internal invariant control. It increased the mRNA levels of MMP-1 while almost no effect on Col-I and TIMPs was observed. CONCLUSIONS: The results indicate that PDL remodeling following application of orthodontic force could be partly attributed to the direct effect of the force on MMP-1 gene expression in fibroblasts.

Actins↗
PubMed2004

High prevalence of osteoarthritis 14 years after an anterior cruciate ligament tear in male soccer players: a study of radiographic and patient relevant outcomes.

OBJECTIVE: To identify the consequences of an anterior cruciate ligament (ACL) tear in a cohort of male soccer players 14 years after the initial injury with respect to radiographic knee osteoarthritis and patient relevant outcomes. METHODS: Of 219 male soccer players with an ACL injury in 1986, 205 (94%) were available for follow up after 14 years; 75% of the cohort (154/205) answered mailed questionnaires (KOOS, SF-36, and Lysholm knee scoring scale) and 122 of these consented to weight bearing radiographs. RESULTS: Radiographic changes were found in 95 (78%) of the injured knees, while more advanced changes, comparable with Kellgren-Lawrence grade 2 or higher, were seen in 50 (41%). In the uninjured knees more advanced changes, comparable with Kellgren-Lawrence grade 2 or higher, were seen in five knees (4%). No differences were seen between surgically and conservatively treated players. The patient relevant outcome was affected and did not differ between subjects with and without radiographic changes. Eighty per cent reported reduced activity level. CONCLUSIONS: A high prevalence of radiographic knee osteoarthritis was seen in male soccer players 14 years after an ACL disruption. The injury and the osteoarthritis, irrespective of the treatment provided to these patients, often result in knee related symptoms that severely affect the knee related quality of life by middle age.

Adult↗
PubMed2003

Re-evaluation of the RBE of 29 kV x-rays (mammography x-rays) relative to 220 kV x-rays using neoplastic transformation of human CGL1-hybrid cells.

Neoplastic transformation of human CGL1-hybrid cells was examined after exposure to 29 kV x-rays (mammography x-rays) and conventional 220 kV x-rays. The study was designed to repeat, under well-defined irradiation and culture conditions, an earlier investigation by Frankenberg et al. (Radiat Res, 2002), and to assess the validity of the high RBE values of 29 kV x-rays that had been reported. The experiments with the two types of x-rays were performed simultaneously and shared the same controls. The transformation yields with both radiation qualities were fitted to the linear-quadratic dependence on absorbed dose, and a corresponding analysis was performed for the data earlier obtained by Frankenberg et al. The transformation yields in the present study exceed those in the earlier investigation substantially, and it appears that the difference reflects inadequate feeding conditions of the cell cultures in the early experiments. The standard error bands of the dose response curves are derived and are seen to be considerably more narrow in the present results. The lowest dose of the 29 kV x-rays was 1 Gy in both studies, and at this dose the RBE vs. the conventional x-rays has now been found to be 2 with a 95% confidence interval of 1.4-2.6. The previous result was about 3.2, but the 95% confidence is very broad for these data. The estimated limit at low doses is 3.4 in the present experiments with a confidence interval that extends from less than 2 to large values.

Carcinogenicity Tests↗
PubMed2003

[Phylogeny, form and function of canine teeth in the horse].

The canine teeth of the horse developed phylogenically from the simple, pointed, short-rooted tooth form of the leaf eating, in pairs living, Eocene horse Hyracotherium and served up to the Oligocene as a means of defense (self preservation). In the Miocene the living conditions of the Merychippus changed and they took to eating grass and adopted as a new behavior the life in a herd. The canine teeth possibly played an important role in fights for social ranking; they changed from a crown form to knife-like shape. In the Pliohippus the canine tooth usually remained in male horses and since the Pliocene, it contributed to the fights between stallions, to ensure that the offspring only came from the strongest animals (preservation of the species). Form and construction of the canine tooth are described and discussed in detail under the above mentioned phylogenic and ethologic aspects.

Animals↗
PubMed2003

The maximum low-dose RBE of 17.4 and 40 keV monochromatic X rays for the induction of dicentric chromosomes in human peripheral lymphocytes.

Schmid et al. recently reported on the maximum low-dose RBE for mammography X rays (29 kV) for the induction of dicentrics in human lymphocytes. To obtain additional information on the RBE for this radiation quality, experiments with monochromatized synchrotron radiation were performed. Monochromatic 17.4 keV X rays were chosen for comparison with the diagnostic mammography X-ray spectrum to evaluate the spectral influence, while monochromatic 40 keV X rays represent a higher-energy reference radiation, within the experiment. The induction of dicentric chromosomes in human lymphocytes from one blood donor irradiated in vitro with 17.4 keV and 40 keV monochromatic X rays resulted in alpha coefficients of (3.44 +/- 0.87) x 10(-2) Gy(-1) and (2.37 +/- 0.93) x 10(-2) Gy(-1), respectively. These biological effects are only about half of the alpha coefficients reported earlier for exposure of blood from the same donor with the broad energy spectra of 29 kV X rays (mean energy of 17.4 keV) and 60 kV X rays (mean energy of 48 keV). A similar behavior is evident in terms of RBEM. Relative to weakly filtered 220 kV X rays, the RBEM for 17.4 and 40 keV monochromatic X rays is 0.86 +/- 0.23 and 0.59 +/- 0.24, respectively, which is in contrast to the RBEM of 1.64 +/- 0.27 for 29 kV X rays and 1.10 +/- 0.19 for 60 kV X rays. It is evident that the monochromatic radiations are less effective in inducing dicentric chromosomes than broad-spectrum X rays with the corresponding mean energy value. Therefore, it can be assumed that, for these X-ray qualities with broad energy spectra, a large fraction of the effects should be attributed predominantly to photons with energies well below the mean energy.

Chromosome Aberrations↗
PubMed2002

[The origin and function of the enamel cup, infundibulum dentis, on the incisors of the horse].

The enamel cups of equids originated phylogenetically through several phases in Oligocene and Miocene horses, which readjusted from hard to soft leaf food and from double nutrition (leaves and grass) to a pure grass intake. This has been proved experimentally. The resulting construction of the incisor is continually changed on its occlusal surface by erosion according to the pattern of the enamel crests. Referring to the whole incisor tooth, this results in an equid life cycle in which the good grip of the occlusal surface and the efficiency of ingestion favours the young, sexually mature horses, which are at the best age for food intake.

Age Factors↗
PubMed2002

Heavy ion RBE and microdosimetric spectra.

Reliable values for the relative biological effectiveness (RBE) of the complex field of heavy ions is essential for radiation therapy with carbon beams. Clinical experience with this novel form of therapy is still quite narrow and it is, therefore, desirable to compare and combine relevant clinical findings and theoretical approaches. One major source of available information comes from neutron therapy. The approach towards the determination of RBE for neutron therapy is, therefore, tentatively applied to the heavy ion therapy. This includes the determination of microdosimetric spectra and their numerical evaluation towards the determination of RBE. A microdosimetric detector on the basis of a tissue-equivalent proportional counter (TEPC) was developed for measurements in the heavy ion fields of the GSI, Darmstadt. Measurements were performed first near the perspex phantom surface with carbon ion energies between 89 MeV.amu-1 and 430 MeV.amu-1. Subsequently, measurements were taken at various depths in the neighbourhood of the Bragg region. The numerical techniques that were developed for neutron therapy lead to tentative values of the RBE that are compared to the RBE values from the biophysical model developed at the GSI. The comparison is still preliminary but can be helpful in modifying the microdosimetric approach for its application in heavy ion therapy.

Equipment Design↗
PubMed2001

Basic fibroblast growth factor suppresses tropoelastin gene expression in cultured human periodontal fibroblasts.

Growth factors are known to play a major role in the regeneration of the periodontium. Basic fibroblast growth factor (bFGF) is a polypeptide growth factor considered to have a role in chemotaxis and mitogenesis of periodontal ligament (PDL) cells. The aim of this study was to assess the effect of bFGF on the transcription level of tropoelastin. As known controls, we assessed the transcription levels of collagen type I, collagen type II and the housekeeping gene, actin. Initially, PDL cells were cultured without bFGF for 3, 7 and 14 days. At each time point. total RNA was extracted and the levels of transcription were assessed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) assay. The results showed that tropoelastin mRNA is transcribed in PDL cells and its levels increased from minimal amounts by day 3 to maximal amounts by day 14 of culture. We further examined the effect of the addition of 10 ng/ml bFGF to the culture media by day 14. The results showed that the addition of bFGF suppressed the transcription level of tropoelastin. At that time, as expected, a decrease in collagen type I transcription level was shown, while the transcription level of collagen type III was not affected. The findings that elastin is transcribed in vitro by PDL cells, but only negligibly in vivo, imply mechanisms that downregulate or even shut down the expression of the elastin gene in the functioning PDL. Basic FGF might be one of the cytokines involved in control of elastin expression in vivo.

Actins↗
PubMed2001

[The phylogenesis of equine teeth].

Phylogenetic research on the teeth of equidae beginning with dagger Hyracotherium ('Eohippus') will be summarized, subdivided into its components, analysed in a new way and finally interpreted according to several theories of evolution. In this context, specific cells (ameloblasts, odontoblasts, cementoblasts) are discussed and valued according to Preuss (1987) as active carriers of the evolution of teeth.

Animals↗
PubMed2001

Long-term outcome of meniscectomy: symptoms, function, and performance tests in patients with or without radiographic osteoarthritis compared to matched controls.

OBJECTIVE: To describe the long-term influence of meniscectomy on pain, functional limitations, and muscular performance. To assess the effects of radiographic osteoarthritis (OA), gender and age on these outcomes in patients with meniscectomy. DESIGN: 159 subjects (35 women), mean age 53 years, were examined 19 (17-22) years after open meniscectomy. Self-reported symptoms and function were assessed, performance tests were carried out and radiographs were taken. Sixty-eight age- and gender-matched controls were examined likewise. The data was analysed in two steps. First, subjects with meniscectomy were compared to the controls, and subgroup analyses were carried out with regard to radiographic OA, gender and age. Second, similar comparisons were carried out within the meniscectomized group. RESULTS: Meniscectomized subjects reported significantly (P< 0.001) more symptoms and functional limitations than did controls. This was also true when operated subjects without OA were compared to controls without OA. Within the meniscectomized group, severe radiographic OA (joint space narrowing grade 2 or more) and female gender, but not older age, was associated with more symptoms and functional limitations. Meniscectomy was associated with worse muscular performance. Female gender and older age were associated with worse muscular performance in the study group. CONCLUSIONS: Meniscectomy is associated with long-term symptoms and functional limitations, especially in women. Patients who had developed severe radiographic OA experienced more symptoms and functional limitations. Age did not influence self-reported outcomes, however older age was associated with worse muscular performance.

Activities of Daily Living↗
PubMed2001

[Principals of construction in the forepaw and hindpaw of the domestic cat (Felis catus). III: Musculature].

With regard to muscular mass and inner structure, the muscles of the forepaw and hindpaw of the domestic cat are grouped functionally, compared and evaluated. A high degree of functional adaptation is present in these muscles, for example in the passive locomotion apparatus of the paws. The domestic cat is not a 'running animal' like other domestic mammals. Also, in domestication it has preserved a strongly individual way of life and has remained a quick, ambushing hunter and climber on the run. Hence its forepaw is a flexible guiding and gripping apparatus, while its hindpaw provides stability for sprinting and non-skid pushing. The partly re-interpreted functions of the muscles are described and listed in four tables.

Animals↗
PubMed2000

Biosensor analysis of the interaction between immobilized human serum albumin and drug compounds for prediction of human serum albumin binding levels.

The interactions between a set of drugs, selected on the basis of reported human serum albumin (HSA) binding levels, and immobilized HSA were investigated using surface plasmon resonance technology. Major HSA binding sites were available after immobilization. The intensity of the signal obtained from the interaction of the drug with the HSA surface was correlated with the reported HSA binding level. Drugs were classified into groups corresponding to high, medium, or low HSA binding based on the injection of the drug at 80 microM concentration. A set of 10 drugs binding to alpha(1)-acid glycoprotein (AGP) was also investigated and correlated with reported AGP binding data. The throughput of the presented assay is 100 compounds/24 h, and the sample consumption is less than 100 microL (8 nmol).

Binding Sites↗