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Biomedical subjects

D Rumpf

Publications and source records attributed to D Rumpf.

13 recordsLinked to original sources
PubMed2001

Influence of hyperbranched multi-methacrylates for dental neat resins on proliferation of human gingival fibroblasts.

We have previously shown that hyperbranched multi-methacrylate (H-MMA)-modified dental resins have VLC activities, lower polymerization shrinkage, and improved mechanical properties, compared to the 2,2-bis[4-(2-hydroxy-3-methacryloyolxypropoxy)phenyl]propane/triethyleneglycol dimethacrylate (BisGMA/TEGDMA) neat resin. The results are due to the unique molecular structure and high molecular weight of H-MMA intermediates. The purpose of this study was to evaluate the biocompatibility of H-MMA-modified dental neat resins. The cell proliferation of three human gingival fibroblast strains on either H-MMA, BisGMA/TEGDMA, or a polystyrene disk was examined. Following 10 days of cell proliferation, there was no statistical difference in cell number between H-MMA-modified and unmodified resin disks. H-MMA-modified resins had less free monomer leaching than the unmodified resin but showed similar properties in water sorption and contact angle values. All these results suggest that the biocompatibility of H-MMA-modified dental neat resins is as good as that of commercially used BisGMA/TEGDMA resin and H-MMA has potential applications in dental composites.

Adult↗
PubMed2000

Acoustic energy affects human gingival fibroblast proliferation but leaves protein production unchanged.

BACKGROUND, AIMS: Sonic toothbrushes are well-established in oral home care for plaque removal; however, the effects of low frequency acoustic (sonic) energy released from sonic toothbrushes to the cells of the periodontium have not been investigated. The purpose of this study was to evaluate the effects of sonic energy on human gingival fibroblast proliferation and protein production in cell culture. METHODS: Direct and indirect transfer calibration studies found the fundamental frequency of the Sonicare sonic toothbrush to be 261 hertz (Hz) with amplitudes ranging from 70 to 104 decibels (dB) in the human periodontium. Using an in vitro delivery system, which coupled a signal-wave generator with a bone transducer to mimic the energy delivered by the Sonicare toothbrush, the effects of signal, amplitude and duration were evaluated longitudinally using a gingival fibroblast cell culture model. 8 strains of fibroblasts isolated from healthy human gingiva were seeded at 30,000 cells/35 mm culture dish in minimum essential medium supplemented with 10% fetal bovine serum. To ascertain the relationship of the amplitude and the duration of sonic stimulation to cellular proliferation, gingival fibroblasts were subjected 2x daily to 261 Hz sound at various amplitudes (67-97 dB) for 0, 15, 30, 60, and 120 s on days 1, 3, 5, 7, and 10. RESULTS: It was found that either 30 or 120 s of sound exposure for 10 days of treatment had significant effects on cell proliferation in comparison to control cultures. Specifically, at day 10, 87 dB at 261 Hz for 30 s 2x daily resulted in a 25.5% increase in cell number (p<0.001), whereas 87 dB at 261 Hz for 120 s twice daily caused a 30.9% decrease in cell number (p<0.001) when compared to control cultures. When cells are stimulated under optimum acoustic conditions for 10 days, there was no difference between the treatment and control groups for collagen (p=0.897) or noncollagen (p=0.697) protein production. CONCLUSIONS: Sonic energy has been shown to both increase and decrease cellular proliferation depending on exposure time; however, during optimum sound-induced conditions for cellular proliferation, sonic energy had no effect on fibroblast protein production. These data suggest that sonic energy can affect the behavior of cells in culture. Further research into the mechanisms of these changes will provide important information for manipulating cellular behavior.

Analysis of Variance↗
PubMed2000

Gender-specific differences in temporomandibular retrodiscal tissues of the goat.

Healthy, adult, male and female goat temporomandibular retrodiscal tissues were characterized to determine if biochemical differences existed between the genders. RNA concentrations were not different between male and female retrodiscal tissues; however, the DNA concentration in female retrodiscal tissues was 82% greater than in male retrodiscal tissues. Collagen concentrations were significantly greater in male retrodiscal tissues, and this was reflected in significant gender differences of type I and III collagen concentrations. More specifically, male temporomandibular retrodiscal tissues contained 70% more type I collagen and 119% more type III collagen when compared to female retrodiscal tissues. These differences in collagens and DNA reflect a gender difference in temporomandibular retrodiscal tissue composition that underlies divergent biomechanical and neurophysiological properties.

Animals↗
PubMed1999

Trauma modifies strength and composition of retrodiscal tissues of the goat temporomandibular joint.

OBJECTIVES: Temporomandibular pain is often accompanied by pathologic changes to joint retrodiscal tissues. The substantial representation of females in this condition has encouraged hypotheses which link genetic or hormonally induced abnormalities in tissue composition (type III collagen, type I collagen, type III/type I ratio) to the development of temporomandibular disorders. As this condition is often associated with a history of orofacial trauma, we investigated the functional impact of retrodiscal trauma on the composition and biomechanics of retrodiscal tissues. DESIGN AND METHODS: Retrodiscal tissue of female goats received trauma or sham trauma. Following a healing period of 30 days, the tissues were pulled to failure on an extensometer. OUTCOME MEASURES: Assessments were made of tissue biomechanical properties (failure force, elastic stiffness, strain distribution). Tissue fragments were assayed for collagens I and III. RESULTS: Thirty days after surgical section of retrodiscal tissues, the tissue had reformed, but the composition and biomechanics were substantially changed. Healed tissue manifested less than half the strength of normal tissue (P = 0.02). In addition, the development of tissue strain shifted from a relatively even distribution to a confined region near the retrodiscal-discal attachment zone. It appeared that a large increase in the expression of type III collagen (179.6%; P = 0.038) and the ratio of type III/type I collagen (180.9%; P = 0.011) accounted for these functional changes. CONCLUSIONS: We suggest that shifts in collagen expression following injury create shifts in strain development which focus tissue stresses near the interface of the disc and retrodiscal tissue, and that this shift dramatically weakens the tissue and increases the probability of re-injury, inflammation and pain.

Animals↗
PubMed1989

Blunted LH surge after HCG administration in cycles superovulated for in-vitro fertilization.

The preovulatory pattern of serum luteinizing hormone (LH) was investigated in cycles superovulated for in-vitro fertilization (IVF). The method used was immunoradiometric assay which shows no cross-reactivity with human chorionic gonadotrophin (HCG) at concentrations usually found after HCG administration. Of the 245 cycles stimulated by clomiphene citrate + human menopausal gonadotrophin, an endogenous LH surge was observed in 29.8% of the patients shortly prior to the HCG injection. In the post-HCG period, 49.4% of the cycles exhibited a blunted LH rise, whereas in the remaining 20.8% the LH level did not exceed twice the mean preovulatory value. According to the oestradiol-17 beta (E2) and progesterone concentrations, different hormonal patterns were found in patients with pre-HCG and post-HCG elevation of LH. However, the occurrence of a blunted LH surge following HCG administration cannot be attributed to different, HCG-induced secretory patterns of progesterone. There were no significant differences in clinical parameters, the pregnancy rate was slightly but not significantly higher (19.0%) in the post-HCG LH surge group than in the two other groups (13.7%). It is presumed that various factors may contribute to the suspension of preovulatory LH suppression. The possible beneficial influence of a post-HCG surge of LH requires further investigation.

Chorionic Gonadotropin↗
PubMed1989

Early pregnancy wastage following late implantation of embryos after in-vitro fertilization and embryo transfer.

Serial plasma concentrations of human chorionic gonadotrophin (HCG), progesterone and oestradiol were measured in pregnancies after in-vitro fertilization and embryo transfer. The first detection day of HCG after embryo transfer (8.4 +/- 1.1) and the HCG doubling time (DT) of 64 normal singleton pregnancies were compared to those of 14 first-trimester miscarriages. The same parameters were evaluated in nine late-implanted conceptions, seven of which resulted in early pregnancy wastage. The HCG DT of late-implanted pregnancies was consistent with that of singleton term pregnancies in the first 12 days, while first-trimester miscarriages which had implanted at the usual time had a significantly longer DT from implantation onwards. The reduced trophoblastic secretory rate suggests poor embryo quality in these cases. A decreased progesterone/oestradiol ratio was observed in late-implanted pregnancies but because of the small number of individuals, no definite conclusion can be drawn. More patients with delayed implantation should be tested to justify this observation.

Adult↗
PubMed1988

Zygote intrafallopian transfer (ZIFT): evaluation of 42 cases.

ZIFT offers the embryologic follow-up of fertilization combined with the advantage of natural tubal transport of embryos to the uterus. Comparing ZIFT pregnancy data to the patients' failed IVF-ET cycles, it is premature to conclude that these pregnancies were exclusively due to the early intrafallopian transfer of zygotes, but the results are encouraging.

Adult↗
PubMed1987

Premature luteinization of follicles during ovarian stimulation for in-vitro fertilization.

The structure and growth of developing follicles was monitored using vaginal ultrasound scanning in an outpatient programme of in-vitro fertilization (IVF) and embryo transfer (ET). Patients received either human menopausal gonadotrophin (HMG) alone or clomiphene citrate (CC) + HMG for controlled ovarian stimulation. Ultrasound data were compared with pre-ovulatory oestradiol (E2), luteinizing hormone (LH) and progesterone (P) levels. Hormonal parameters and results were classified according to the main indications of IVF-ET treatment. Twenty-one of the 271 patients in the study showed ultrasonic evidence of premature luteinization (PL) of follicles, thickening of the follicular wall and the appearance of irregular echogenic structures in the follicle. PL was preceded in eight cases by an indisputable LH surge and subsequent P elevation. In the remaining 13 cases PL occurred either due to an abortive LH surge not exceeding by 3-fold the baseline values or as a result of HMG administration. Special attention was paid to the P pattern prior to and after human chorionic gonadotrophin (HCG) administration. PL cycles demonstrated significantly (P less than 0.05) higher P levels before HCG administration and at the time of oocyte retrieval as well. Because implantation was not achieved in these cases, the cancellation of PL cycles is recommended. Vaginal ultrasound scanning seems to be helpful in the evaluation of minor changes in the follicular structure, correlating frequently with hormonal findings.

Clomiphene↗
PubMed1986

Prognostic value of laser interferometric visual acuity in amblyopia therapy.

There has been no simple clinical test which accurately predicts post-therapy visual acuity in amblyopic eyes. Since grating test patterns generally yield optimal visual acuity in amblyopic eyes, the authors sought to determine if pre-therapy laser interferometric grating visual acuity would predict conventional post-therapy visual acuity in functional amblyopia. In 90% of the patients who completed therapy, the pre-therapy laser visual acuity was within two lines of the post-therapy Snellen visual acuity. Thus, pre-therapy laser visual acuity is a good prognostic indicator of conventional post-therapy visual acuity in amblyopic eyes.

Adolescent↗
PubMed1985

Contrast and accommodation in amblyopia.

Steady-state accommodation as a function of sinusoidal and square-wave grating contrast was measured in amblyopes. The amblyopic eyes exhibited reduced average response levels and required greater contrast to sustain accommodation than the fellow dominant eye or the eyes of visually-normal control subjects. Following therapy, accommodation in the amblyopic eye markedly improved. These results suggest: reduced accommodative controller gain, reduced stimulus effectiveness of target contrast, and considerable residual visual system plasticity with respect to the neurological control pathways of accommodation, in the amblyopic eye.

Accommodation, Ocular↗
PubMed1978

Encouraging behavior changes by use of client-held health records.

A process was developed to encourage individuals to take more responsibility for their health by using a client-held health record. The motivation for the record, called a Personal Life Health Plan (PLHP), stems from the fact that the majority of ills which afflict an individual can be abated by behavior changes. The PLHP contains most of what is in a medical record but also has sections which deal with health maintenance; a past health history, a family health history, tables of individualized risks of morbidity and mortality, a health maintenance plan, and tables of physiological measurements. The PLHP process helps to make explicit the steps of 1) naming existing and potential health problems; 2) reflecting on their causes; and 3) taking actions to overcome them. Additionally, the record helps maintain continuity of care. Pilot studies made in two settings indicate that a significant percentage of individuals will use a PLHP and that physicians and nurse practitioners can incorporate it into their routine of providing care with minimal expenditures of time. Longer term studies will be required to determine effects on behavior, compliance and health services utilizations.

Behavior Therapy↗
PubMedDate not supplied

Containers for waste causing peritonitis in CAPD patients.

Fungal infection is a rare cause of peritonitis in patients on chronic peritoneal dialysis. In this population, fungi are found in less than 2 percent of all cases of primary episodes of peritonitis (1). More often, a primary bacterial peritonitis treated with antibiotic therapy leads to secondary fungal infection (2). Candida species cause 74.5% of the episodes of fungal peritonitis (2). The fungi invade the peritoneal cavity from the skin peri- or intraluminally through the catheter (3). Filamentous fungi are rare (4,5). Treatment of fungal peritonitis commonly consists of removal of catheter and antifungal drugs (3). Here we describe two cases of fungal peritonitis caused by mycelial fungi, where the source of the microorganism could be special containers used for biological waste, which are popular in Germany

Adult↗