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Biomedical subjects

R Krauspe

Publications and source records attributed to R Krauspe.

At least 73 records · Page 4Linked to original sources
PubMed1988

Synthesis of diadenosine 5',5'''-P1,P4-tetraphosphate by organellar and cytoplasmic phenylalanyl-tRNA synthetases of Euglena gracilis.

Purified phenylalanyl-tRNA synthetases present in chloroplasts, mitochondria and cytoplasm of green and bleached Euglena gracilis strains, respectively, are able to synthesize diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A). Ap4A synthesis is strictly dependent on zinc ions. This is the first evidence that chloroplasts should be able to synthesize Ap4A. Synthesis of Ap4A by phenylalanyl-tRNA synthetases of the three compartments of a plant cell or by other enzymes such as Ap4A phosphorylase is discussed.

Adenine Nucleotides↗
PubMed1986

Coomassie brilliant blue G-250 dye-binding technique for determination of autolytic protein breakdown in Euglena gracilis and comparison to other methods of autolysis measurement.

The Coomassie brilliant blue G-250 dye-binding technique of M. M. Bradford (1976, Anal. Biochem. 72, 248-254) for protein quantification has been used to measure autolytic protein breakdown in cell-free extracts of Euglena gracilis. Specific autolysis rates were calculated from the difference between initial and actual absorbances at different incubation times of Coomassie brilliant blue-stained protein. They were found to depend linearly on time and initial protein concentration. Calibration against another method of protein determination is necessary due to different color yields with various protein mixtures. The high sensitivity and reproducibility of this method permit determination of specific autolysis rates below 0.1% mg-1 h-1 over a pH range between 3 and 8, without protein precipitation or pH adjustment, and in the presence of high amounts of amino acids and/or small peptides. Results obtained by this method are comparable to those of other autolysis measurements and to proteolytic activity determination by azocaseinolysis. Proteolytic autolysis has been observed in both the soluble and the particulate fractions of E. gracilis cell-free extracts, but displays different pH optima and specific activities in these fractions, as is also the case for azocaseinolysis. The method described is easy to perform, inexpensive, time saving, and should be applicable to other biological systems as well.

Animals↗
PubMed1984

Activation of postganglionic neurones via non-nicotinic synaptic mechanisms by stimulation of thin preganglionic axons.

Activity in postganglionic neurones supplying skeletal muscle and hairy skin of the cat hindlimb was measured after single and repetitive stimulation of preganglionic axons in the lumbar sympathetic trunk at variable stimulation strengths. Simultaneously the compound action potentials were measured in one of the lumbar white rami L2 or L3. Early short latency ("nicotinic") responses were obtained in the postganglionic neurones when preganglionic axons conducting at 8.9 +/- 3.44 m/s (n = 12) or less were stimulated. Late, long-latency non-nicotinic responses were elicited in the postganglionic neurones when preganglionic axons conducting at 1.52 +/- 0.94 m/s (n = 12) or less were stimulated.

Action Potentials↗
PubMed1983

Photoaffinity labeling of chloroplastic and cytoplasmic leucyl-tRNA synthetases of Euglena gracilis by the gamma-(p-azidoanilidate) of ATP.

The photoreactive gamma-(p-azidoanilidate) analog of ATP, AzAnATP, was used to affinity-label the chloroplastic and cytoplasmic leucyl-tRNA synthetases of Euglena gracilis. The analog is able to replace the substrate ATP in the tRNA leucylation reaction catalyzed by both enzymes. In the presence of ATP, it is a competitive inhibitor against ATP as well as leucine for the two isoenzymes, as is also shown for the photoinactive gamma-anilidate analog of ATP, AnATP, which does not serve as substrate in the enzyme reaction. During ultraviolet irradiation, the enzymes are irreversibly inactivated by AzAnATP in a concentration-dependent and time-dependent manner indicative of photoaffinity labeling. Both ATP and leucine, but not tRNA, protect the enzymes against ultraviolet-induced inactivation by AzAnATP. Comparative kinetic characterization of the inactivation process reveals differences in the active centers of the two intracellular isoenzymes.

Adenosine Triphosphate↗
PubMed1983

Reflex activation of postganglionic vasoconstrictor neurones supplying skeletal muscle by stimulation of arterial chemoreceptors via non-nicotinic synaptic mechanisms in sympathetic ganglia.

Postganglionic sympathetic neurones supplying skeletal muscle and skin can be activated from the preganglionic site via cholinergic nicotinic, muscarinic and noncholinergic synaptic mechanisms. The experiments described in this paper were designed in order to show that postganglionic vasoconstrictor neurones supplying skeletal muscle can be activated by the naturally occurring discharge pattern in preganglionic axons when the nicotinic transmission is blocked. For this purpose, the activity was recorded simultaneously from postganglionic vasoconstrictor axons supplying skeletal muscle and vasoconstrictor axons supplying hairy skin. The preganglionic neurones were driven reflexly by stimulation of the arterial chemoreceptors. 1) During blockade of nicotinic transmission muscle vasoconstrictor neurones were activated via the CNS during stimulation of arterial chemoreceptors. This activation is either generated by muscarinic action of released acetylcholine or by a noncholinergic synaptic mechanism. 2) Postganglionic cutaneous vasoconstrictor neurones were inhibited during stimulation of arterial chemoreceptors. During blockade of cholinergic nicotinic transmission these neurones were not activated reflexly by stimulation of arterial chemoreceptors although they received inputs via cholinergic muscarinic and noncholinergic synaptic mechanisms. 3) The results illustrate that postganglionic vasoconstrictor neurones supplying skeletal muscle can not only be activated via non-nicotinic synaptic mechanisms through synchronous repetitive electrical stimulation of preganglionic axons but also by the discharge pattern produced in preganglionic neurones during stimulation of arterial chemoreceptors.

Animals↗
PubMed1983

Vimentin filaments in peritoneal macrophages at various stages of differentiation and with altered function.

Comparative immunofluorescence microscopic, transmission and scanning electron microscopic investigations were carried out to study the arrangement and significance of vimentin filaments in monocytes, macrophages, epithelioid cell equivalents and multinucleate giant cells under various different functional conditions, and in the presence of functional disorders. Uncoated or sebum-coated coverslips were implanted in the peritoneal cavity of Wistar rats. Some of the animals received repeated i.p. injections of colchicine. Rats were killed at various times 1 to 14 days after initiation of the experiment. The number of macrophages, the degree of their activation, and the growth of cells on the coverslips was considerably greater on sebum-coated than on uncoated implants. Various characteristic vimentin distribution patterns were found dependent on the cell cycle, the form and volume of the cell, and on the degree of differentiation and maturity; they were also related to the type and intensity of cell function. These patterns were best developed in ordered multinucleate giant cells. Repeated administrations of colchicine resulted in a marked flattening of the cell body on the coverslips--which correlated with a considerable reduction in the number of vimentin filaments and of cytoplasmic processes--and also in the formation of circumscribed erect, tree-like protuberances. The "trunk" of these structures comprised closely bundled vimentin filaments, and the cell nucleus was located at its base. These morphologic changes, which were associated with a functional insufficiency, proved to be reversible.

Animals↗
PubMed1982

Transmission of impulses from pre- to postganglionic vasoconstrictor and sudomotor neurons.

Transmission of impulses of pre- to postganglionic neurons supplying skeletal muscle and skin of the cat's hindlimb and tail was investigated. The objective of the study was to determine whether these postganglionic neurons can be influenced from the preganglionic side by non-nicotinic synaptic mechanisms in the lumbar sympathetic chain ganglia. The activity of the postganglionic neurons was recorded from their axons being isolated from peripheral skin and muscle nerves. (1) Vasoconstrictor neurons can be activated by muscarinic action of released acetylcholine and by a non-cholinergic synaptic mechanism. This type of non-nicotinic excitation of postganglionic vasoconstrictor neurons requires the activation of thin, probably unmyelinated preganglionic axons and considerable summation. Postganglionic sudomotor and pilomotor neurons cannot be activated in this way. (2) Ongoing activity in postganglionic vasoconstrictor neurons, but not in sudomotor neurons, can be enhanced for up to 60 min by brief trains of stimuli applied to the preganglionic site. Also this enhancement requires the activation of thin preganglionic axons. (3) Stimulation of thin preganglionic axons leads to an activation of muscle vasoconstrictor neurons via non-nicotinic synaptic mechanisms in the ganglia after complete block of nicotine transmission. (4) Postganglionic vasoconstrictor neurons and sudomotor neurons may be inhibited by a catecholaminergic autogenic mechanism in the ganglia. (5) The results indicate that integration may take place in the sympathetic chain ganglia by other than divergent and convergent processes. In this integration muscarinic actions of released acetylcholine and non-cholinergic synaptic mechanisms may be involved.

Acetylcholine↗
PubMed1982

The cytoskeleton in activated and in functionally disordered cells of the macrophage system.

In animal experiments, and for various granulomatous diseases of humans, components of the so-called cytoskeleton in cells of the macrophage system were investigated in the electron microscope and with the aid of indirect immunofluorescence microscopy using monospecific antibodies. In young monocytes and in non-activated or only slightly activated mononuclear phagocytes, predilection areas and characteristic patterns of arrangement were found: F-actin is observable, densely arranged, in particular, around the nucleus and below the cytomembrane; intermediate filaments of the vimentin type form a broad, intensely fluorescent wreath around the cell nucleus; microtubules radiate from the perinuclear centriole in all directions into the neighbouring cytoplasm, taking the form of a microaster. Modifications of this pattern of distribution begin in the pre-mitotic phase, and become highly evident in karyokinesis and cytokinesis. Increases in the cell function are associated with changes in the arrangement of the cytoskeleton of quite a different nature, in particular in the regions of the cytomembrane, the cytocentre, including the Golgi dictyosomes and neighbouring portions of the rough endoplasmic reticulum, at sites of endocytosis and exocytosis and polarization and orientation, and in conjunction with intracytoplasmic translocations after the fusion of macrophages to form multinucleate giant cells. We do not consider the findings described here to be a sort of more or less static compartimentalization phenomenon, but, rather, believe them to bear a causal relationship to the functional dynamism of highly activated and specially differentiated macrophages, epithelioid cell equivalents, epithelioid cells and giant cells. Moreover, they are suggestive of function-dependent, intimate interactions of the individual cytoskeletal components. The experimental, reversible disturbance by the use of colchicine leads in macrophages to a transient loss of structural and functional identity with drastic alterations of microtubules and vimentin filaments.

Adult↗
PubMed1978

[Inhibition of leucyl-tRNA-synthetases by modified ATP analogs].

The interaction between modifying ATP analogs containing alkylating or phosphorylating groups in the polyphosphate moiety of the ATP molecule and leucyl-tRNA synthetases from cytoplasm and chloroplasts of Euglena gracilis (strain Z) was studied. It was shown that most of the ATP analogs irreversibly inhibit the cytoplasmic enzyme, having no inhibiting effect on the chloroplast synthetase. The kinetic constants K1 and k2 for the interaction between the most effective irreversible inhibitors and the cytoplasmic enzyme were determined. The data on the protection of the enzyme activity by substrates against irreversible inhibition suggest, that the effect of the adenosine 5'-(beta-chloroethyl phosphate) is directed to the ATP-binding site of the cytoplasmic enzyme, whereas the mixed anhydride of AMP and mesithylene carbonic acid acts predominantly on the binding site of 3'-terminal adenosine of the tRNALeu molecule. ATP analogs may be effectively used for affinity labelling of the cytoplasmic leucyl-tRNA synthetase.

Adenosine Triphosphate↗
PubMedDate not supplied

[Minimal invasive therapy of localized Langerhans-cell histiocytosis of bone].

PURPOSE: Scaglietti introduced a method of steroid injection for the management of unicameral bone cysts in 1974. Subsequently the intralesional infiltration of corticosteriods has also been recommended as a primary therapy for localized Langerhanscell histiocytosis (LCH). We report our experience with the administration of methylprednisolone acetate in children and young adults localized LCH. MATERIAL AND METHODS: [corrected] Nine patients with localized LCH, aged 2 3/12 to 29 years, were treated with a single--in only one case two--intralesional injection of methylprednisolone acetate as a crystalline suspension. The dose was between 40 and 150 mg depending on the size of the radiolucent defect. We treated 4 lesions in the skull, 3 in the femur, 1 in the distal humerus and 1 in the mandibula. In each case the diagnosis was established by biopsy. Follow-up ranged from 2 to 8 8/12 years (4 years 4 months on average). RESULTS: 7 out of 9 patients with localized LCH had excellent results with complete healing of the lesion. In 2 patients there was no response to the initial injection therapy and dissemination of the disease occurred. In 4 patients with an additional soft tissue tumor, after injection therapy of the bone lesion, the soft tissue tumor resolved without further treatment. CONCLUSION: Intralesional infiltration of methylprednisolone acetate as a primary therapy for localized Langerhans cell histiocytosis leads to rapid relief of pain, restoration of bone morphology and reduction of associated soft tissue tumors. Performed with appropriate skill under sterile condition with the reported high percentage of effectiveness and low recurrence rate, this low invasive method is the treatment of choice, resulting in a lower morbidity and lower costs.

Adolescent↗
PubMedDate not supplied

[Prospective randomized comparative study of early functional outcome of 2 knee joint endoprosthesis systems--rotation plateau versus fixed polyethylene inlay].

AIM: Different systems are used for total knee arthroplasty (TKA). Compared were a press-fit femur condyle replacement system with fixed tibial PE-inlay versus a rotating tibia component system with an emphasis on the early functional results. METHOD: Patient selection and the use of the Knee Society Score for this randomized and prospective study were based on the directives for TKA of the german Society for Orthopaedic and Trauma Surgery (DGOT). We examined the patients post-operatively after 1 week, 2 weeks, 6 weeks, 3 months, 6 months, and 1 year. RESULTS: After 6 weeks an increase of the total knee score could be seen in both groups. The total knee score of the rotating tibia component increased from 93.96 pre-operatively to 113.57 after 6 weeks, to 139.82 after 3 months, to 154.32 after 6 months, and to 159.65 after one year. The total score with the fixed PE-inlay increased from 79.75 to 111.5 after 6 weeks, to 128.25 after 3 months, to 134.08 after 6 months, and to 130.08 after one year. CONCLUSION: After 6 weeks the implant with the rotating tibia component showed a lasting higher score as compared to the implant with a fixed PE-inlay component using the same early rehabilitation and mobilization techniques.

Aged↗
PubMedDate not supplied

[Medical-insurance aspects of atlantoaxial instability in children].

INTRODUCTION: An os odontoideum is mostly diagnosed coincidentally on the basis of neurological symptoms or painful movement of the cervical spine. Diagnostic work-up and therapy are currently subjects of controversial discussion in the literature. CASE: Our report is about an eleven-year-old boy with an unknown os odontoideum, who developed neurological symptoms with tetraparesis after a fall from 1.5 m height. Conventional X-ray examination resulted in the diagnosis of a suspected dens fracture, MRI showed atlanto-axial instability and an os odontoideum with significant dural sack compression but no signs of acute bony or ligamentous lesion. CONCLUSION: Because of the importance concerning not only medical but also legal/insurance aspects, a possible coincidental finding of an os odontoideum versus a dens fracture must be included in the differential diagnosis. In the case of an os odontoideum without instability in children, conservative therapy is justified after due enlightenment regarding possible risks. In the event of neurological symptoms and/or persistent instability the authors advocate early surgical stabilization even in patients with little infirmity, particularly in view of the possible consequences.

Accidental Falls↗
PubMedDate not supplied

[Primary synovial chondromatosis of the shoulder].

AIM: To demonstrate the various patterns of primary synovial chondromatosis (PSC) around the shoulder and to discuss a therapeutic algorithm. METHOD: In this retrospective study, 6 patients with histologically proven PSC were operated on. The diagnosis was based on clinical examination, plain X-rays, ultrasonography and MRI in 5/6 patients. Also, a histological examination was done in all cases. According to the localisation of the disease, surgery was done by endoscopy alone, endoscopy together with open surgery or direct open surgery. RESULTS: In one case each, we saw an isolated disease of the subacromial bursa or the gleno-humeral joint. In two cases, we found an intraarticular affection together with the biceps tendon sheath. The other two patients showed a massive periarticular deposition of loose bodies together with a defect of the rotator cuff. All patients with intraarticular disease (5/6) showed different stages of chondromalacia. In 5 of 6 patients all bodies could be removed at surgery. At follow-up after 36 months the patients subjectively rated the result as satisfactory to excellent. In the patients with total removal of the bodies, no recurrences were seen on plain X-ray or ultrasonography. CONCLUSION: PSC around the shoulder appears with a variable pattern. According to the possible late complications described in the literature (i. e., secondary osteoarthritis, involvement of the rotator cuff and secondary malignant transformation), we find operative treatment justified. Surgery addressing removal of loose bodies and partial synovectomy allows good results. The operative approach (endoscopy or open surgery) is related to the localisation and severity of the condition.

Adult↗
PubMedDate not supplied

[Medical-legal aspects in fractured ceramic liners after implantation of a hip endoprosthesis].

We report the case of a male patient after implantation of a thrust plate endoprosthesis to discuss reliable questions concerning the insurance and liability fields. The indication for implantation of this type of endoprosthesis should be decided critically. To prevent an early implant failure, both articulating ceramic partners - the liner and the femoral head - should be exchanged in any case of doubt during a hip revision surgery. In case of an implant failure, a surface analysis of the broken fragments can show signs of material insufficiencies. A detailed preoperative consent of the patient combined with an exact documentation is necessary to prevent potential medical claims by the patient, and also increases the compliance and reduces the costs for the health system.

Adult↗
PubMedDate not supplied

[Clinical and radiological short- and mid-term results of triple pelvic osteotomy according to Tönnis in adolescents and adults].

AIM: We report our clinical and radiological results after triple pelvic osteotomy according to Tönnis and accompanying femoral osteotomies in selected cases. METHOD: 48 patients were evaluated in a retrospective study with an average follow-up to 2 years and 9 months. RESULTS: In 68 % of our patients excellent to good results in the Harris Hip Score were achieved. We could significantly decrease pain awareness. The CE angle improved significantly from 10.6 degrees to 32.2 degrees and the acetabular angle of the weight-bearing zone according to Bombelli from 20.8 degrees to 3.8 degrees at the last follow-up. The VCA angle according to Lequesne and de Seze improved from 18.6 degrees to 33.5 degrees. Non-union of the ischial or the pubic bone developed in 7 cases as a relevant complication. CONCLUSION: On the basis of our results and the literature, the triple pelvic osteotomy according to Tönnis can be recommended for the treatment of acetabular dysplasia in adolescents and adults.

Acetabulum↗