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Biomedical subjects

G Eckert

Publications and source records attributed to G Eckert.

50 records · Page 3Linked to original sources
PubMed1977

Bioavailability evaluation of an enteric-coated phenylbutazone formulation, and cross-over comparison with a sugar-coated product.

The relative bioavailability of enteric-coated, and commercially available sugar-coated tablets of phenylbutazone (PBZ) was studied in eight healthy volunteers. Each subject received a single oral dose of 400 mg of each preparation in a cross-over sequence. Blood samples were taken for assay of unchanged drug at intervals up to 360 hours. In an attempt fully to characterize the absorption and elimination profiles, three bioavailability parameters were evaluated; peak plasma level of PBZ, time taken to achieve peak level, and area under the plasma level-time curve. Peak plasma levels of PBZ, and area under the plasma level-time curves were not significantly different for the two products, which indicated their bioequivalence. A statistically significant (P is less than 0.001) difference in the rate of absorption of the two products was apparent, since the mean time of occurrence of the peak plasma level of PBZ for the enteric-coated tablets was 9.0 hours compared with 3.9 hours for the sugar-coated formulation. No subjective effects from the two products were noted by any of the subjects, nor were there any alterations in haematological or biochemical parameters.

Adult↗
PubMed1977

[Thrombophoresis II. Effects of thrombocyte separation on the blood donor (author's transl)].

The separation of approximately 75% of the platelets present in circulation and thrombocyte pool in healthy adult donors by continuous flow centrifugation lowers the mean thrombocyte concentration to 140 +/- 28 X 10(3)/microliter. A dangerous thrombocytopenia can not occur since the platelet count in the reinfused erythrocyte zone remains at around 88 X 10(3)/microliter. The reactive rise of the platelet count after separation, the extend of which depended on the total amount of harvested thrombocytes, reached values around 277 X 10(3)/microliter. The total thrombocyte yield exceeded the calculated yield by 30%, indicating emptying of a quiescent thrombocyte pool. Thrombopoietin activity could be demonstrated in donors' plasma at 12 and 24 hours after thrombophoresis.

Blood Cell Count↗
PubMed1975

[Amenorrhoea after oral contraceptives].

Eleven women with amenorrhoea after taking oral contraceptives were studied. A clomiphene stimulation test was performed in ten, with six also having an LH-RH stimulation test. In most of them there was no reaction or a severely impaired response to both clomiphene and LH-RH, but bleeding episodes could be provoked in most women by continuing clomiphene treatment, and some of these ovulated when HCG was added to the therapeutic scheme. A possible relationship between preexisting psychosomatic disorders and the genesis of postcontraceptive amenorrhoea is discussed.

Adolescent↗
PubMed1975

Humoral and cellular immune reactions 'in vitro' against allogeneic and autologous human melanoma cells.

Based on 51Cr release from an allogeneic human melanoma cell (M1) cell-mediated (CMC) and antibody-dependent cellular cytotoxicity (ADCC) were determined in twenty-eight melanoma patients, thirty-one healthy controls, ten patients with other tumours and eleven chronic lymphocytic leukaemia (CLL) patients. The results were related to simultaneously performed microcytotoxicity (MC) tests, HL-A typing, plasma membrane fluorescence and B:T cell ratios in the peripheral blood. Furthermore, lymphocytes from six melanoma patients were tested in CMC and ADCC assays against autologous tumour cells. The following results were obtained. (1) A large number of healthy controls possessed lymphocytes which readily lysed M1 target cells in CMC and MC assays. (2) CMC activity of lymphocytes from melanoma patients was generally lower than that of control lymphocytes and decreased further with progression of the disease. (3) CLL lymphocytes were virtually non-toxic for M1 cells, even at high aggressor:target cell ratios. (4) ADCC assays with a heterologous rabbit-anti-M1 serum showed generally higher isotope release than CMC assays; this was particularly pronounced in the melanoma group and in the group of patients with other tumours. (5) No tumour-specific blocking factor could be detected in melanoma sera, as judged by the capacity of the sera to block CMC activity. (6) No obvious correlation was found between the results obtained in short-term CMC and long-term MC assays. (7) T lymphocytes, as determined by E-rosette formation, were significantly diminished in melanoma patients. (8) The HL-A type of lymphocytes from normal donors and melanoma patients did not appear to be related to high or low activity in CMC and MC assays. (9) Preliminary results of 51Cr release tests with autologous melanoma cells were encouraging with respect to the correlation of the results to the clinical course of the disease.

Antibodies, Neoplasm↗
PubMedDate not supplied

Detection of early interproximal caries in vitro using laser fluorescence, dye-enhanced laser fluorescence and direct visual examination.

This in vitro study evaluated the use of laser fluorescence (LF) for the detection of early interproximal carious lesions and whether the detection could be enhanced using a fluorescent dye (DELF). Direct visual examination (DV) was used for comparison. Eighty extracted teeth were used, arranged in 20 blocks, each block having 2 premolars and 2 molars, lined up in a simulated sextant situation. After cleaning with a microabrasion kit, a subcontact window on half of the surfaces (60) was exposed to Carbopol white-spot solution for 5 days. The teeth were remounted in stone and examined by three independent examiners. For LF and DELF an argon laser was used (mixed wavelength of 488 and 514 nm) viewed through glasses (excluding wavelength <520 nm). For DELF a sodium fluorescein dye (0. 075%) was applied before examination. A clinical examination light was used for DV. The approximal surfaces were scored for lesion presence or absence. To verify lesion presence, the subcontact area was cut perpendicularly to the surface, stained with rhodamine B, and images were taken using a confocal microscope. The images were analyzed using a histogram program for lesion depth and image area. Lesions were present in 62 out of 120 approximal surfaces, with an average depth of 60 microm (range 17-190 microm). Sensitivity ranges for LF, DELF and DV were 56-74, 61-79 and 58-74%, and specificity ranges 67-78, 86-98 and 83-97%, respectively. With this model DELF compared favorably with DV and LF in sensitivity, but specificity was better for DELF and DV than for LF.

Bicuspid↗
PubMedDate not supplied

Spectral analysis of viscoelasticity of the human lens.

PURPOSE: In the aging lens, two different structural changes become progressively apparent: loss of accommodation and formation of cataract. These changes are due to different alterations in lens structure taking place on a molecular scale. METHODS: For the characterization of liquids, gels, elastic bodies and solids, dynamic mechanical analysis (DMA) represents a non-destructive macroscopic analysis method with considerable sensitivity to microscopic structural changes. Spectra of the shear compliance (reciprocal shear modulus) of human lenses at different ages were measured in a wide frequency range (1 mHz to 1 kHz). By means of computer analysis, the parameters of the involved relaxation processes and the viscous flow were determined. RESULTS: The increase in cross-linking density was correlated with the disappearance of viscous flow in the measured spectra. The accumulation of high-molecular-weight aggregates was held responsible for the shift of the lower frequency relaxation process to lower frequencies with increasing stiffness, which is likely to be correlated with a prolonged accommodation time. CONCLUSION: Dynamic mechanical analysis represents a useful method for the spectroscopic characterization and quantification of the changes in the macroscopic viscoelastic properties caused by molecular changes in cataract formation and loss of accommodation.

Aged↗
PubMedDate not supplied

Increased frequency of HLA-Bw62 and Bw35 CREG antigens in HLA-B27 negative ankylosing spondylitis.

67 patients with ankylosing spondylitis (AS) were tissue-typed for HLA-A, -B and -C antigens. HLA-Bw62 was found in 6 of 13 (46%) HLA-B27 negative patients, compared to 9% in HLA-B27 positive AS (p greater than 0.01) and 10% in healthy blood donors (p greater than 0.001). HLA-Bw62, a split of the previous HLA-B15, belongs to the HLA-Bw35 CREG antigens, 11 of 13 (85%) of HLA-B27 negative patients had an HLA-Bw35 CREG antigen. The present results are interpreted as an indication of a direct involvement of the HLA-B locus in the pathogenesis of AS.

Adult↗