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Biomedical subjects

R Reimann

Publications and source records attributed to R Reimann.

At least 19 recordsLinked to original sources
PubMed1996

Studies for a genotoxic potential of some endogenous and exogenous sex steroids. II. Communication: examination for the induction of cytogenetic damage using the chromosomal aberration assay on human lymphocytes in vitro and the mouse bone marrow micronucleus test in vivo.

The cytogenetic potential of 10 sex steroids (cyproterone acetate, drospirenone, gestodene, cyclodiol, cyclotriol, ethinylestradiol, atamestane, lilopristone, onapristone and propylmesterolone) with various medical indications was determined using the chromosomal aberration test in human lymphocytes in vitro and the mouse bone marrow micronucleus test in vivo. Nine of these sex steroids (gestodene was omitted) were investigated in the human lymphocyte assay and found to be negative with respect to the induction of chromosomal aberrations either with or without metabolic activation. In all assays the highest concentration evaluated was either clearly cytotoxic or, in case of noncytotoxicity, resulted in visible precipitates in the culture medium. Evaluation of the data from the mouse bone marrow micronucleus test indicated that the seven steroids (cyproterone acetate, drospirenone, gestodene, ethinylestradiol, atamestane, onapristone and propylmesterolone) investigated failed to induce enhanced frequencies of micronucleated polychromatic erythrocytes in male and female mice. The steroids were tested up to dose levels which induced signs of toxicity in the experimental animals or, in the case of non toxic compounds, the animals were treated up to the maximum recommended dose of 2 g/kg body weight. Evaluation of all data indicates that the investigated estrogens, progestins and other sex steroids had no genotoxic potential detectable with the chromosomal aberration assay on cultured human lymphocytes or the mouse bone marrow micronucleus test.

Animals↗
PubMed1996

Formation of DNA-adducts by selected sex steroids in rat liver.

1. We are reporting investigations into the potential of the steroid hormones chlormadinone acetate (CMA), cyproterone acetate (CPA), ethinylestradiol (EE2) gestodene (GEST), megestrol acetate (MGA), norethisterone acetate (NET-Ac), estradiol (E2), and progesterone (P) to form DNA-adducts in rat liver in vivo. 2. Compound-related DNA-adduct spots were detected in male and female rat liver following CMA, CPA, and MGA using the 32P-postlabeling-technique. Substance-specific DNA-adducts were also observed in male rats after administration of E2. The other compounds showed no DNA-adduct formation. After treatment with CMA, CPA or MGA, the relative adduct labeling (RAL) differed sex- and substance-specifically.

Animals↗
PubMed1996

Brainstem auditory evoked potentials in respiratory insufficiency following encephalitis.

Brainstem auditory evoked potentials (BAEPs) were recorded in 14 artificially ventilated patients (12 males, 2 females; mean age 33.3 +/- 16.3 years, range 18-67) with respiratory insufficiency resulting from severe inflammatory encephalopathies. The results were compared with those of 17 healthy volunteers (13 males, 4 females; mean age 27.4 +/- 5.3 years, range 21-45). BAEPs in the study patients showed prolonged interpeak latencies (I-III, I-V, III-V, IV-V) and delayed absolute latencies of waves I, II, III, and V at least on one side. Because the auditory pathways are in the near vicinity of the respiratory control centers in the brainstem, the electrophysiologic abnormalities of wave III and the IV/V complex may be a reflection of the disturbed central control of ventilation.

Acoustic Stimulation↗
PubMed1996

Abnormal brain stem auditory evoked potentials in a girl with the central alveolar hypoventilation syndrome.

Brainstem auditory evoked potentials were recorded in a 3-year-old girl with the central alveolar hypoventilation syndrome (Ondine's syndrome). Abnormal findings were seen at the level of the mid to upper brain stem (wave III), which was not reproducibly recordable on the left side. This electrophysiologic abnormality is consistent with a previous finding in a patient with sleep apnea.

Child, Preschool↗
PubMed1996

[Controversial rotation function of certain muscles in the hip joint].

The disputed rotating function of certain muscles in the hip joint. A device constructed for that study allows to determine the rotating function of the iliopsoas muscle as well as of the uniarticular adductor muscles of the thigh in every position of the hip joint by the method of threads. The iliac muscle rotates the thigh inward in every position of flexion/extension or abduction/adduction of the hip joint. The adductor magnus muscle always is a lateral rotator by those fibres which are inserted into the medical edge of the linea aspera, while the fibres attached to the adductor tubercle rotate the thigh inward. The psoas major, pectineus, adductor longus and adductor brevis muscles are able to rotate the thigh inward as well as outward. Their rotating function depends on the specific position of flexion/extension and abduction/adduction of the hip joint: Flexion and abduction intensify the lateral rotating function of these muscles, extension and adduction intensify the medial rotating function.

Aged↗
PubMed1993

Studies for a genotoxic potential of some endogenous and exogenous sex steroids. I. Communication: examination for the induction of gene mutations using the Ames Salmonella/microsome test and the HGPRT test in V79 cells.

The mutagenicity results and data of nine progestins (cyproterone acetate, dehydrospirorenone, gestodene, gestonorone caproate, levonorgestrel, norethisterone, norethisterone acetate, norethisterone enanthate, norethynodrel), one hypothetical metabolite (6,7-epoxy-cyproterone acetate), four estrogens (estradiol, ethinylestradiol, cyclodiol, cyclotriol), and four other sex steroids (atamestane, lilopristone, onapristone, propylmesterolone) are reported. All 17 sex steroids were investigated using the Ames salmonella/microsome direct plate incorporation protocol, and seven were additionally tested using the preincubation modification. Seven sex steroids were also studied in the HG-PRT test with V79 cells for the induction of gene mutations in mammalian cells. The metabolite was examined in the Ames salmonella/microsome assay using the standard protocol and the preincubation modification. In all assays the test compounds were investigated up to concentration levels where cytotoxicity and/or visible precipitation occurred or at least the solubility limit of the test compound was reached. For all assays, evaluation of the data indicates that neither any of the sex steroids nor the hypothetical metabolite was able to induce gene mutations whether in the absence or the presence of an extrinsic metabolizing system (S9 mix).

Animals↗
PubMed1992

[Biomechanics of the joints of the large toe. Shape and movement of the first tarsometatarsal joint and of the medial cuneonavicular joint].

90% of the first (hallucal) tarsometatarsal joints are screw-shaped; the axis is directed upwards to the front touching the lateral edge of the joint. Thus the plantar flexion is inevitably accompanied by an adduction and a pronation, and vice versa a dorsiflexion is consequently accompanied by an abduction and a supination, when the articular surfaces exactly slide along each other. 10% of these joints, however, are ellipsoid-shaped; in this case the distal articular surface of the medial cuneiform bone has the form of an ovoid head, and a strong ligament situated next to the lateral edge of the joint effects the same kind of motion described above. The medial cuneonavicular joint is always ellipsoid-shaped, the head of which is made up by the medial facet of the distal articular surface of the navicular bone. Each of the two joints mentioned has a considerable range of mobility.

Biomechanical Phenomena↗
PubMed1991

[Manual examination of so-called lumbosacral instability].

By the manual test of the lumbosacral instability described by Eder and Tilscher we can never find out for certain whether the fifth lumbar vertebra can be shifted ventrally above the sacrum. Before this test the patient has to be turned over on to his side with hips flexed, which causes a ventral flexion (anteflexion) of the lumbosacral segment. During the test, however, the lumbosacral segment is forced to a dorsal flexion (retroflexion); therefore the spinous process of the fifth lumbar vertebra retires from the back surface simulating a sliding forward of the whole vertebra.

Adult↗
PubMed1990

[The effect of morphologic variety on the biostatics of lumbosacral transition].

Variants shown by the orientation of the cover-plate and of the superior articular facets of the sacrum have a considerable influence on the lumbosacral biostatistics. This can be illustrated by parallelograms of forces. If we assume a certain force stressing upon the sacrum, we are able to calculate the distribution of stress upon the cover-plate and the articular facets by help of the size and the orientation of these weight bearing faces.

Humans↗
PubMed1989

[The biostatics of the human sacrum: is there a relationship between the sacral inclination and the spatial orientation of the upper articular process of the sacral plate?].

The orientation of the superior articular processes with regard to the upper end-plate of the sacrum does not depend on the inclination of the sacrum. This assertion can be made by interpreting certain angles already described in literature and may be confirmed by a research following strict biomechanic principles: The orientation of the articular processes is put in relation to the direction of the forward shear brought upon by the Vth lumbar vertebra and caused by the inclination of the sacrum. This is achieved by measuring the angle between the articular facet and a plane normal to the mentioned forward shear. The result is that the size of this angle does not at all depend on the degree of the inclination of the sacrum.

Adult↗
PubMed1988

[Models of the geometry of the human ankle bone pulley: two series of geometric models for demonstrating the biomechanics of the ankle joint].

2 series of models demonstrate the geometrical shape of the human trochlea tali. We have changed step by step the shape of the 2 flanking articular facets of the trochlea, the course of the edges of the trochlea, and the length of their radii, and so we have found a model responding to the biomechanic conditions of the trochlea tali. The convex surface of this model (corresponding to the superior articular surface, i.e. the facies superior trochleae tali) is a torse, the medial flanking facet (corresponding to the medial articular facet of the trochlea, i.e. the facies malleolaris medialis) is a flat cone, the lateral flanking facet (corresponding to the lateral articular facet of the trochlea, i.e. the facies malleolaris lateralis) is a screwed (helicoidal) face. The resulting model shows the 2 completely different phases of motion in the ankle joint: During dorsiflexion (motion setting out from the neutral position towards the final position of dorsiflexion), the internal malleolus leads the talus, whereas the external malleolus is pushed outwards by the screwed lateral articular facet of the trocheal. The trochlea is moved like a hinge. In the final position of dorsiflexion, the malleoli tightly embrace the 2 flanking facets of the trochlea, whilst an obvious cleft appears dorsally and medially between the superior articular surface of the trochlea and the tibial roof (i.e. the facies articularis inferior tibiae). During plantarflexion (motion setting out from the neutral position towards the final position of plantarflexion), the external malleolus leads the talus, whereas the medial articular facet of the trochlea withdraws from the internal malleolus. The trochlea is moved like a screw. In the final position of plantarflexion, the superior articular surface of the trochlea closely contacts the tibial roof, whilst an obvious cleft appears between the medial articular facet of the trochlea and the internal malleolus.

Ankle Joint↗
PubMed1988

[The lumbosacral transition: morphologic variations and their functional significance].

The articular facet of a superior articular process of the sacrum is directed backward, inward, and upward with marked variations. 4 angles characterize the orientation of this facet: a) The relative angle of tilt: i.e. the angle between the articular facet and the upper end-plate of the sacrum, measured in a sagittal plane. b) The absolute angle of tilt: i.e. the angle between the articular facet and the horizontal plane, measured in a sagittal plane. c) The tilted part-angle of opening: i.e. the angle between the articular facet and the sagittal plane, measured in a plane parallel to the upper end-plate of the sacrum. d) The horizontal part-angle of opening: i.e. the angle between the articular facet and the sagittal plane, measured in a horizontal plane. These 4 angles are determined by characteristic straights within the articular facet and certain reference planes (upper end-plate of the sacrum, horizontal plane, sagittal plane). Only 2 intersecting straights suffice for an adequate determination of a geometrical plane; therefore, if we know the relative angle of tilt and the tilted part-angle of opening, we are able to construct or to calculate the absolute angle of tilt as well as the horizontal part-angle of opening by using the range of inclination of the sacrum. The shape as well as the orientation of the articular facets at the superior articular processes of the sacrum do not depend on the inclination of the pelvis nor on the inclination of the sacrum nor on the range of the lumbosacral angle. Only the absolute angle of tilt shows a reference to the inclination of the sacrum because the relative angle of tilt shows a certain constancy. The orientation of the articular facets is slightly influenced by static moments, but considerably determined by dynamical requirements. At spines with irregular numbers of praesacral vertebrae, the orientation of the lumbosacral articular facets do not differ from the orientation of these facets at spines with the regular number of 24 praesacral vertebrae. This, however, does not prove right at spines, that have a lumbosacral "transitional vertebra". Such lumbosacral transitional vertebrae detract much from the stability of the lumbosacral region of the spine.

Adult↗
PubMed1987

[Cervix and tocography screening in basic pregnancy monitoring].

Report about a myometrial contractility-screening in 2462 asymptomatic pregnancies at 30 weeks of gestation. A cervical examination was performed in the 26th and 33th weeks of gestation. An increased uterine contraction frequency was obtained in 3% and a cervical opening in 5.6%. Uterine contractions with cervical opening are a high-risk factor of prematurity (52%-70%) whereas uterine contractions alone are of low-risk. The prevention of preterm birth is useful. We found a significant decrease of early neonatal mortality in 487 singleton preterm deliveries after treatment. A classification of unexplained preterm delivery, iatrogenic or elective preterm delivery and complicated preterm labor is recommended for controlled outpatient and clinical trials.

Female↗
PubMed1986

[Pneumothorax after mediastinal emphysema. The site and mechanism of pleural rupture].

By rupture of the mediastinal pleura a mediastinal emphysema may lead to a pneumothorax. An experiment imitating this process is able to point out two spots where the pleura is most likely to tear: An area as large as a thumb tip above the root of the left lung; there mediastinal pleura covers a space the width of which changes most in respirating. The border of a fatty fold based on the pericardium and covered by mediastinal pleura; it is there that maxima of tension occur by emphysematic inflation. In general, air from the mediastinum far more often enters the left pleural cavity than the right one.

Aged↗
PubMed1986

[The geometry of the human trochlea tali].

The geometrical shape of the trochlea tali is responsible for two completely different courses of motion in the ankle joint setting out from the neutral position: dorsiflexion and plantar flexion. Dorsiflexion: The tibia leads the talus, whereas the fibula is pushed laterally by the screw-shaped lateral articular facet of the talus. The malleoli tightly embrace the trochlea tali, whilst an obvious cleft appears dorsally and medially between the superior articular surface of the talus and the tibial roof. Plantar flexion: The fibula leads the talus which withdraws from the medial malleolus by stretching the anterior talofibular ligament. At the same time the superior articular face of the talus closely contacts the tibial roof.

Ankle Joint↗