Biomedical subjects
Publications and source records attributed to G Holzapfel.
Several methods for characterization of microcapsules developed in connection with optimizing and controlling the properties of capsules based on polyelectrolyte complexes (PEC) using sodium cellulosesulphate (NaCS) and poly(dimethyldiallylammonium chloride) (PDMDAAC) as complex forming components are briefly reported.
Bioassays and immunoassays of protein hormones often read different parts of the molecule and give conflicting results. Therefore, we studied the LH bioactivity (bLH; mouse Leydig cell testosterone production assay) and immunoreactive LH (irLH) using five immunoassays [one conventional polyclonal RIA and four immunometric sandwich assays using monoclonal antibodies (mAB)] in five women suffering from polycystic ovarian disease (PCOD). Blood samples were taken from these patients at 10-min intervals for 24 h. Data were analyzed by the PC Pulsar pulse detection program. As described by others, bLH is increased in PCOD patients, and LH pulse frequency is largely accelerated (18-28 pulses/24 h). Almost every LH pulse was detected by the polyclonal RIA, whereas all mAB immunoassays detected significantly fewer pulses than the bioassay or the RIA. Occasionally, irLH pulses were detected by some assay systems when bLH activity did not increase, and there was a great difference in the temporal occurrence of bLH and irLH pulses. It is concluded that the type of immunoassay used for the detection of LH levels is also of importance for the number of detected LH pulses. Furthermore, each mAB immunoassay appears to detect different epitopes on the LH molecule, such that different conformational and/or glycosilated states are identified. Often, irLH pulses occur with no concurrent bLH pulses, which may indicate that the pituitary in PCOD patients releases pulses of biologically inactive LH in response to hypothalamic GnRH release. Hence, the pituitary gonadotrophs must be in some degree of synchrony in producing such biologically inactive material.
PSA is an important tumor-marker for prostatic cancer disease. We developed a sensitive, simple and inexpensive Sandwich ELISA for PSA with two monoclonal antibodies. The precision and reliability of the assay are reflected in the low inter- and intraassay coefficient of variation. PSA was not detectable in sera from normal females (n = 50). Sera from males with different serum levels of PSA (normal males, patients with prostate hypertrophy, prostate cancer patients, n = 79) and 15 prostate cancer patients treated with Zoladex were measured by our ELISA and by a commercially available RIA. The correlation coefficient between these both test systems was close to 1 (r = 0.97).
The testet mechanical amalgamators DMG 410 (VEB Dentalfabrik Treffurt) showed sufficient tightness. After dosing and trituration of 5 (during 30 min) and of 25 amalgam mixtures (during 2 hours) an increase of the mercury vapour concentration was measured from 0.003 mg Hg/m3 air of the room (blank value) to 0.008 mg Hg/m3 air of the room and to 0.018 mg Hg/m3 air of the room in an unventilated room. A significant decrease of the mercury vapour concentration could be established within 10 minutes by ventilation of the measurement room.
Ovarian follicular fluid (FF) of a number of species contain regulatory peptides secreted by granulosa cells or by autonomic nerve terminals. In this report we demonstrate the presence of authentic (HPLC-verification) angiotensin II and III as well as of substance P (SP) in human FF obtained from hMG stimulated infertile patients undergoing in vitro fertilization. Angiotensin II/III (AII/III), estradiol (E2) and progesterone concentrations increase with the size of the follicles. SP concentrations did not vary significantly in FF of various sizes. These peptide concentrations in FF are about 10-fold higher than those measured in the serum of the same patients. Attempts to correlate SP, AII/III, E2 and progesterone concentrations in the individual FF with the ability of an oocyte to be fertilized, failed. Neither AII/III, SP, E2 nor progesterone concentrations were different in these subclasses of FF. Follicles of patients punctured under general anesthesia contained significantly more SP than follicles of patients which had lumbar analgesia. AII/III concentrations were the same in FF of both treatment groups. The presence of angiotensin II and III in FF in increasing concentrations depending on the maturity of the follicle and the inability of general anesthesia to affect the AII/III concentrations suggests that this peptide is produced within the ovary.
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Triton extraction of mouse 3T3 cells provides cellular models able to contract in a Ca2+-dependent manner upon exposure to MgATP. Such models reveal myosin kinase (MLCK) along their microfilaments and contraction is inhibited by antigen affinity-purified antibodies to gizzard MLCK. When extraction is performed at higher salt concentrations the models become non-contractile and immunofluorescence microscopy fails to detect the kinase. Inactive models can be functionally reactivated by exposure to exogenously provided purified kinase plus calmodulin present in the normal buffer. Reconstituted models again reveal microfilament-associated kinase. Functional reconstitution requires both the addition of kinase and calmodulin and does not occur in the presence of trifluoperazine. The combined results indicate that contractility of non-muscle cellular models is controlled by calmodulin-dependent MLCK acting on the actin-myosin-containing microfilaments with a calcium control exerted in the phosphorylation step of myosin.
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