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Biomedical subjects

B Schmidt

Publications and source records attributed to B Schmidt.

At least 433 records · Page 24Linked to original sources
PubMed1988

Fibrinogen has a rapid turnover in the healthy newborn lamb.

The half-lives for coagulation factors in the healthy newborn infant are not known and may be different than for the adult. We measured the half-life for fetal sheep fibrinogen and compared it to the half-life of adult sheep fibrinogen. Fibrinogen was purified from adult and fetal sheep plasma and radiolabeled with either 125I or 131I. The half-lives for these fibrinogens were determined in the adult sheep and newborn lamb. In addition, the fetal and adult sheep fibrinogens were compared by reptilase time, thrombin clotting time, sialic acid content, and the behavior of the N-glycans derived from these fibrinogens on the immobilized lectin, Sepharose-concanavalin A. Finally, the in vivo response of coinjected radiolabeled fibrinogens to increasing doses of infused thrombin was determined. The fetal sheep fibrinogen differed from the adult as indicated by a prolonged reptilase time and an increased sialic acid content (fetal: 10-11 residues/340 Kd versus adult: 8-9 residues/340 Kd). The latter was also reflected in differing chromatographic profiles for the N-glycans on Sepharose-concanavalin A. The half-lives for both the adult and fetal fibrinogen were significantly more rapid in the newborn lamb (fetal: 47 +/- 2.0 h; adult: 46 +/- 2.4 h, mean +/- SEM) than in the adult (fetal: 116 +/- 6.5 h; adult: 121 +/- 6.9 h). Finally, the adult and fetal sheep fibrinogen responded to thrombin in an identical fashion in the intact animal. In summary, both adult and fetal fibrinogen have faster half-lives in the lamb compared tot he adult, despite a higher sialic acid content for the fetal fibrinogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1988

[Te place of radiotherapy in the treatment of local recurrences of rectal cancer].

A retrospective study was conducted on 67 patients irradiated between 1976 and 1983 at the Medical Radiologic Institute of Tübingen for local recurrences of primarily operated carcinomas of the rectum. Generally, a total dose of 50 to 60 Gy was applied partially in form of a rotational therapy with individual doses of 2 Gy each. The irradiation was well tolerated by most of the patients. The troubles which were mostly severe and progressive before radiotherapy could be relieved by the irradiations in 91% of the patients. This palliative effect lasted for twelve months on an average. The prognosis quoad vitam is unfavorable with a median survival time of 21 months and a three-year survival rate of 15%. A clear dependence on the dose was not found for any of these parameters. Our own results are compared to those communicated by other authors. It is shown that better results can only be achieved by re-operation performed in sano.

Adult↗
PubMed1988

[Neuroblastoma of the olfactory nerve. Radiotherapy experiences in 6 patients].

Six patients with neuroblastomas of the olfactory nerve (esthesioneuroblastoma) are presented who were irradiated between 1983 and 1986 at the Medical Radiologic Institute of Tübingen. Clinical manifestations, diagnostics, histology, therapy, and courses are compared and discussed with regard to a survey of literature. An attempt is made to find out the value of radiotherapy in the treatment of this rare disease. In stage A (tumor restricted to the nasal cavity, 1 patient), a local tumor control of up to now 28 months could be achieved by a treatment combination of surgery and radiotherapy. A treatment consisting of surgery or radiotherapy alone should even in this stage only be performed in connection with a close follow-up because of the increased local recurrence risk. Tumors of stage B (manifestation in the nasal cavity and the paranasal sinuses) did not occur in this group of patients. Five patients suffered from tumors of stage C (tumor extent beyond the paranasal sinuses). A good palliative effect was obtained temporarily by radiotherapy alone in three out of these patients showing large inoperable tumors and rapidly progressing clinical symptoms. A complete remission now lasting 16 months was achieved only in one patient by radical surgery with unilateral evisceration of orbit and homogeneous postirradiation. In case of stage C tumors it is recommended to perform, if possible, a radical tumor excision with evisceration of orbit in case of unilateral manifestation in the orbit and a postirradiation applying a radical, large volume technique. In order to reduce the risk of radiogenic cerebral necroses, it should be attempted to avoid dose maxima as they can occur when applying a combined ventro-dorsal and lateral irradiation technique.

Adult↗
PubMed1988

[Radiotherapy of bronchial carcinoma].

It is not to be expected that there will be dramatic improvements in the treatment of bronchial carcinoma in the near future. Hence, the only short-term goal that can be aimed at is to optimise treatment modalities in respect of indication and interdisciplinary cooperation, besides strictly realised prevention. With circumscribed small-cell carcinomas radiotherapy in conjunction with chemotherapy can improve intrathoracic remission rates, can delay local recurrences and reduce the incidence of cerebral metastases. With non-small cell carcinomas in circumscribed but inoperable stages radiotherapy is the only--albeit small--possibility of offering a chance of cure. With operated nodal-positive patients, subsequent irradiation improves long-term prognosis. In a palliative situation, carefully applied irradiation techniques that avoid stressful exposure to radiation, can usually achieve relevant improvements in the quality of life.

Carcinoma, Bronchogenic↗
PubMed1988

Standard assays underestimate the concentration of heparin in neonatal plasma.

Heparin is commonly used to treat neonatal thrombosis. Drug monitoring often involves assays that measure the inhibition of added factor Xa or thrombin by the antithrombin III (AT-III) heparin complex. We examined whether the neonatal AT-III deficiency affects heparin recovery in such assays at therapeutic drug concentrations (0.1 to 0.6 U/ml). The chromogenic anti-factor Xa assay (Teien AN, Lie M, Abildgaard U. Thromb Res 1976;8:413-6) and the protamine titration test were performed in eight pooled cord plasma samples and in normal adult plasma. Only 65% to 70% of heparin activity detected in adult plasma was recovered by the assay of Teien et al. In cord plasma; recovery by the protamine test was 80% or less. Heparin recovery in cord plasma was significantly improved by raising the AT-III concentration to normal adult levels in both assays. We conclude that heparin assays underestimate drug levels in neonatal plasma unless the neonatal AT-III deficiency is fully corrected in the test system. The use of standard assays may lead to over-heparinization of newborn infants, thereby placing them at a higher risk of bleeding.

Antithrombin III↗
PubMed1988

Multi-centre evaluation of the Behring ELISA Processor II.

A multi-centre evaluation of the Behring ELISA Processor II in connection with the Enzygnost-tests from Behringwerke was performed by 3 laboratories following the ECCLS Guidelines for the Evaluation of Analysers in Clinical Chemistry. The performance characteristics were studied with analytical tests for anti-HBs1), HBsAg and anti-CMV2). This evaluation represents, to our knowledge, the first trial in clinical virology with guidelines primarily designed for clinical chemistry. The evaluation revealed that the highly automated Behring ELISA Processor II is a reliable tool in the virological laboratory. The data obtained showed low imprecision and good accuracy. The washing unit proved to be very efficient. No carry-over of reagents was detected in the dispenser system. Several improvements for further developments of the analyser are suggested. This multi-centre study has shown that the ECCLS protocol can be used to evaluate analysers and test systems in clinical virology.

Autoanalysis↗
PubMed1987

Genetic heterogeneity of steroid sulfatase deficiency revealed with cDNA for human steroid sulfatase.

Three cDNA clones with inserts of 1.2-1.6 kb that reacted both with antibodies and oligonucleotides specific for steroid sulfatase were isolated from a human placental library in lambda gt11. The 5'-end of one of the inserts, STS-3, was sequenced and colinearity with the amino acid sequence of 3 peptides of steroid sulfatase encompassing 64 amino acids was demonstrated. STS-3 hybridized with 2.5, 4.6 and 6.3 kb species in poly(A)+RNA and with 2.5, 4 and 9 kb fragments of EcoRI digested human DNA. The frequency of the EcoRI fragments in DNA from females was approximately twice that in DNA from males. DNA from two patients with steroid sulfatase deficiency and X-linked ichthyosis did not hybridize with STS-3. DNA from a third patient showed a normal hybridization pattern. It is concluded that steroid sulfatase deficiency is a genetically heterogenous disorder.

Amino Acid Sequence↗
PubMed1987

[Morphologic studies of the pathogenesis of ligneous conjunctivitis].

The cases of ligneous conjunctivitis published since 1964 are presented in a review of the literature. A total of 84 cases have been described. The predominance of this disease in women is lower than was previously thought. Ligneous conjunctivitis tends to occur more frequently in children. However, it is not a "disease of little girls". Two cases are described in the present paper, including pathomorphological studies. In both cases, neutrophilic granulocytes were studied by electron microscopy. The results are compared with a control case and with corresponding reports in the literature. The number of granules in the neutrophilic granulocytes was significantly reduced in both cases. In one of the cases studied the granules were increased in size. These findings support the hypothesis that ligneous conjunctivitis could be the result of a lowered resistance associated with a disturbance of wound healing.

Biopsy↗
PubMed1987

Cloning of a cDNA encoding the human cation-dependent mannose 6-phosphate-specific receptor.

Complementary DNA clones for the human cation-dependent mannose 6-phosphate-specific receptor have been isolated from a human placenta library in lambda gt11. The nucleotide sequence of the 2463-base-pair cDNA insert includes a 145-base-pair 5' untranslated region, an open reading frame of 831 base pairs corresponding to 277 amino acids (Mr = 30,993), and a 1487-base-pair 3' untranslated region. The deduced amino acid sequence is colinear with that determined by amino acid sequencing of the N-terminus peptide (41 residues) and nine tryptic peptides (93 additional residues). The receptor is synthesized as a precursor with a signal peptide of 20 amino acids. The hydrophobicity profile of the receptor indicates a single membrane-spanning domain, which separates an N-terminal region containing five potential N-glycosylation sites from a C-terminal region lacking N-glycosylation sites. Thus the N-terminal (Mr = 18,299) and C-terminal (Mr less than or equal to 7648) segments of the mature receptor are assumed to be exposed to the extracytosolic and cytosolic sides of the membrane, respectively. Analysis of a panel of somatic cell (mouse-human) hybrids shows that the gene for the receptor is located on human chromosome 12.

Amino Acid Sequence↗
PubMed1987

Dissolution of gallstones using cholecystostomy tube in the pig.

Cholecystostomy catheters and human cholesterol gallstones were implanted surgically in the gallbladders of eight pigs. Through the catheters, mono-octanoin or sterile water (H2O) was infused from two to seven days. The mono-octanoin dissolved pure cholesterol gallstones smaller than 200 g. There was no stone dissolution with infusion of sterile water and only one stone larger than 250 g was dissolved with mono-octanoin. Side effects included moderate-to-severe inflammation and ulceration of the gallbladder with mono-octanoin instillation, which precludes its widespread use with the present treatment regimen. Infusion of water caused little gallbladder irritation.

Animals↗
PubMed1987

Ex vivo biocompatibility evaluation of a new modified cellulose membrane.

To evaluate membrane biocompatibility, an open loop ex vivo model was designed simulating the hemodialysis procedure. Blood was withdrawn continuously from healthy nonuremic donors, heparinized, and pumped through a module containing the membrane to be studied. C3a generation in the module was determined at various time points comparing the cuprammonium cellulose (CC) membrane and four types of modified cellulose (MC) membrane, each with a different degree of hydroxyl (OH-) group substitution. In other studies, C3a generation in the ex vivo mode was compared with that during in vivo dialysis. In the ex vivo model, C3a generation with MC membranes was reduced by 70% compared with CC. However, within the MC group, the degree of C3a generation did not correlate with the degree of OH-group substitution. In vivo studies confirmed the reduced degree of C3a generation with the MC membrane compared with CC. Additionally, validation studies using the CC membrane showed excellent agreement between C3a generation during ex vivo perfusion and in vivo dialysis. The results suggest that a group of new MC membranes causes substantially less complement activation than the CC membrane but that the degree of complement activation with various subtypes of MC membranes is not related to the degree of OH-group substitution.

Anaphylaxis↗
PubMed1987

Ex vivo and in vivo protein A perfusion: background, basic investigations, and first clinical experiences.

During the past several years clinical protein A perfusion has attracted much attention because it allows to selectively remove IgG subclasses 1, 2, 4 and probably IgG-containing immune complexes, and has a tumoricidal effect in experimental animals and in some cancer patients. Due to several drawbacks, this therapy is not yet generally accepted. Our first experience with laboratory and clinical protein A perfusions confirms several limitations of this new apheresis therapy. Plasma IgG extraction in the ex vivo system under investigation and during clinical application of protein A perfusion reached a 10:1 ratio of grams IgG removed per gram solid-phase protein A only in 2 of 5 runs. Nevertheless, the absolute amount of IgG removed was very low in all runs due to the restricted protein A load (maximum 200 mg) per column. Removal capacity can be increased by a two-column switch-over system with subsequent perfusion and elution. Furthermore, the side effects observed in both in vivo treatments exceeded by far those of other extracorporeal therapies and had not been observed in more than 1,200 unselective plasma exchanges or in 50 cascade filtrations in our center. C3a generation in protein A perfusion is, however, comparable to cascade filtration, but exceeds that of unselective plasma exchange and is lower than in hemodialysis. Consequently, side effects in protein A perfusion cannot be correlated with the total amount of anaphylatoxin generated but may be due to a leakage of protein A or contaminants. Clinical application of protein A perfusion needs a more detailed elaboration in respect to biocompatibility, removal capacity, and the significance of the induced biological effects.

Adsorption↗
PubMed1987

Complications of frontal defects. Immobilization of the eye.

A case where the severe course of an orbital phlegmon led to a functionally and cosmetically poor condition is presented. Thirty-five years later, it was possible to achieve a satisfactory result through several operations performed with interdisciplinary cooperation. The orbit and forehead were reconstructed with porous polyethylene, thus ensuring a cosmetically good result. In two operations, the left eye was freed from its upward fixation through cicatrectomy and mobilization of the mucles, so that the eyes were straight again in the primary position. There is a limited binocular visual field. Binocular vision could be restored again after an interruption of 35 years.

Adolescent↗