Biomedical subjects

M Engelhardt

Publications and source records attributed to M Engelhardt.

At least 73 records · Page 4Linked to original sources

PubMed1999

Clinical and functional outcome after anatomic and nonanatomic ankle ligament reconstruction: Evans tenodesis versus periosteal flap.

The present study investigated the effects of two different surgical procedures for the treatment of chronic ankle instability. Ten patients treated with an anatomic reconstruction using a periosteal flap were compared with a second group that received an Evans tenodesis. All patients were evaluated before and after surgery with clinical and radiographic examinations as well as dynamic pedobarography. Patient satisfaction and radiographic and functional results were comparable in both groups and revealed a good restoration of joint stability and gait symmetry. Our results indicate that both methods of ankle ligament reconstruction achieve a comparable clinical and functional outcome within 1 year after surgery.

Adult↗

PubMed1999

High-versus standard-dose filgrastim (rhG-CSF) for mobilization of peripheral-blood progenitor cells from allogeneic donors and CD34(+) immunoselection.

PURPOSE: The efficacy of a high- versus a standard-dose filgrastim (recombinant human granulocyte colony-stimulating factor, or rhG-CSF) regimen to mobilize peripheral-blood progenitor cells (PBPCs) for allogeneic transplantation was investigated in 75 healthy donors. PATIENTS AND METHODS: From December 1994 to December 1997, 75 consecutive donors (median age, 38 years; range, 17 to 67 years) were assigned to two different schedules of rhG-CSF for PBPC mobilization. Fifty donors received 24 microg rhG-CSF/kg body weight (BW) divided into two daily subcutaneous injections (two doses of 12 microg, group A), whereas 25 were treated with 10 microg rhG-CSF once daily (group B). Apheresis was started on day 4 in group A and on day 5 in group B. Target CD34(+) cell numbers in apheresis products were >/= 4 x 10(6)/kg recipient BW. RESULTS: Cytokine priming and collection of PBPCs were equally well tolerated in both groups. Significantly higher CD34(+) cell numbers in group A with 3. 7 x 10(6)/kg recipient BW/apheresis (0.47 x 10(6)/L apheresis) compared with 2 x 10(6)/kg recipient BW/apheresis (0.25 x 10(6)/L apharesis) in group B were obtained (P <.05). Using standard aphereses (median, 9 L), two doses of 12 microg rhG-CSF/kg allowed collection of >/= 4 x 10(6)/kg CD34(+) cells with two aphereses (range, one to three) in group A versus three aphereses (range, one to six) in group B (P <.015). Donor age, sex, and BW influenced the collection of CD34(+) cell numbers: in particular, significantly higher apheresis results were obtained in donors younger than 40 years compared with donors older than 40 years of age (P <.05). In 65 CD34(+) selection procedures using avidin-biotin immunoabsorption columns (Ceprate SC System, CellPro, Bothell, WA), a median CD34(+) purity of 53%, CD34(+) recovery of 40%, and the collection of 2 x 10(6)/kg CD34(+) cells/selection were achieved. In group A with higher CD34(+) cells/kg/apheresis, CD34(+) purity, recovery, and cell yields were 60%, 45%, and 2.3 x 10(6)/kg/selection, respectively, as compared with 48%, 31%, and 0.7 x 10(6)/kg in group B (P <.05). CONCLUSION: Our results demonstrate that twice daily rhG-CSF (two doses of 12 microg/kg BM) compared with once daily rhG-CSF (10 microg/kg BW), in addition to being well tolerated, significantly improves PBPC mobilization, allows the collection of higher numbers of CD34(+) cells with one or two standard aphereses, and facilitates subsequent selection procedures in healthy allogeneic donors.

Adolescent↗

PubMed1998

Transport of monoamine transmitters by the organic cation transporter type 2, OCT2.

The recently cloned apical renal transport system for organic cations (OCT2) exists in dopamine-rich tissues such as kidney and some brain areas (Gründemann, D., Babin-Ebell, J., Martel, F., Ording, N., Schmidt, A., and Schömig, E. (1997) J. Biol. Chem. 272, 10408-10413). The study at hand was performed to answer the question of whether OCT2 accepts dopamine and other monoamine transmitters as substrate. 293 cells were stably transfected with the OCT2r cDNA resulting in the 293OCT2r cell line. Expression of OCT2r in 293 cells induces specific transport of tritiated dopamine, noradrenaline, adrenaline, and 5-hydroxytryptamine (5-HT). Initial rates of specific 3H-dopamine, 3H-noradrenaline, 3H-adrenaline, and 3H-5-HT transport were saturable, the Km values being 2.1, 4.4, 1.9, and 3.6 mmol/liter. The corresponding Vmax values were 3.9, 1.0, 0. 59, and 2.5 nmol min-1.mg of protein-1, respectively. 1, 1'-diisopropyl-2,4'-cyanine (disprocynium24), a known inhibitor of OCT2 with a potent eukaliuric diuretic activity, inhibited 3H-dopamine uptake into 293OCT2r cells with an Ki of 5.1 (2.6, 9.9) nmol/liter. In situ hybridization reveals that, within the kidney, the OCT2r mRNA is restricted to the outer medulla and deep portions of the medullary rays indicating selective expression in the S3 segment of the proximal tubule. These findings open the possibility that OCT2r plays a role in renal dopamine handling.

Animals↗

PubMed1998

Molecular cloning and characterization of two novel transport proteins from rat kidney.

The recent cloning of renal transport systems for organic anions and cations (OAT1, OCT1, and OCT2) opened the possibility to search, via polymerase chain reaction (PCR) homology screening, for novel transport proteins. Two integral membrane proteins, UST1 and UST2, were cloned from rat kidney. RT-PCR revealed that UST1 is confined to the kidney whereas UST2 mRNA was detected in all tested tissues. Sequence analyses suggest that UST1 and UST2, together with four related transporters, comprise, within the major facilitator superfamily, a so far unrecognized transporter family, termed amphiphilic solute facilitator (ASF) family. Characteristic signatures for the ASF family were identified.

Amino Acid Sequence↗

PubMed1998

Telomerase activity and telomere length in pediatric patients with malignancies undergoing chemotherapy.

Telomerase activity and telomere length in mononuclear cells (MNCs) and granulocytes from peripheral blood (PB) and bone marrow (BM) specimens were studied in pediatric acute leukemia (ALL, n = 15; AML, n = 11) and pediatric solid tumor (ST) patients (n = 9) at diagnosis, during and after chemotherapy. In four ST patients, tumor tissue was also available. For comparative analysis, MNCs from healthy donors (n = 53) were analyzed. Telomerase was evaluated using a modified telomeric repeat amplification protocol (TRAP) assay, and telomere length by terminal restriction fragment (TRF) analysis. At diagnosis, high telomerase activity was detected in MNCs from all leukemia patients, which was similar to the activity from ST biopsy specimens. This exceeded by 10- to 20-fold the activity in PB MNCs from ST patients and healthy donors (P < 0.05). Granulocyte fractions lacked telomerase activity in all groups. BM MNCs in leukemia patients revealed a four-fold higher telomerase activity than PB (P = 0.005). After induction chemotherapy and response to treatment, telomerase activity decreased to borderline or undetectable levels in PB MNCs in leukemia (P < 0.01). Average telomeres in PB MNCs from pediatric patients were significantly longer (n = 25; 10.9 kbp) than telomeres in PB and BM MNCs from adult healthy donors (7.45 kbp) (P < 0.0001). At diagnosis, telomeres were shorter from BM compared to PB specimens in leukemia (P < 0.05), and two peak TRFs were observed corresponding to the malignant and normal cell clones. With the attainment of remission, the lower TRF peak, reflecting the leukemic population, was lost. In leukemia patients, mean TRFs increased on average 2.2 kbp after induction chemotherapy, but decreased thereafter on consolidation and maintenance chemotherapy (1 kbp). This was comparable to an average telomere loss of 1.2 kbp in PB specimens from ST patients after chemotherapy. In all patients, telomere loss in granulocytes as compared to MNCs was more pronounced with 1.8 vs 1 kbp, respectively (P = 0.014). Our results demonstrate that at diagnosis, telomerase was consistently and highly upregulated in BM and PB specimens in leukemia, decreased after induction therapy, and correlated with remission. BM specimens in leukemia had higher telomerase activity, probably due to the greater leukemic burden than in PB. Telomeres were significantly longer in children than in adults, but shortened as a consequence of chemotherapy with repeated cycles of hematopoietic regeneration. In acute leukemia, with the loss of the leukemic burden after induction chemotherapy, longer mean TRFs were found, a reflection of the repopulation with normal cells. Our findings suggest that telomerase activity may be useful in the management of childhood malignancies. The significance of telomere length shortening in pediatric patients undergoing chemotherapy and possible telomere regeneration after myelosuppressive treatment remain to be determined.

Adolescent↗

PubMed1998

[Stretching--do current explanatory models suffice?].

The opinion that mobility in the usual performance if the "straight leg raise" test for the evaluation of stretching techniques is subject to solety muscular limitations is critically appraised. With integration of recent results from molecular biological research and our own measurements, we can show that not only mechanical but also neurophysiological factors must be considered in the limitation of mobility. In the majority of the examined patients stretching of the ischiadic nerve seems to be responsible for restrictions in movement. The presented results cast doubt on the currently held assumptions and basic principles of stretching in therapy and sport.

Adult↗

PubMed1998

Creatine supplementation in endurance sports.

PURPOSE: Creatine is a physiologically active substance indispensable to muscle contraction. The increase in creatine phosphate obtained by supplementation is greater than the increase in total creatine achieved by specific sports training. Less well-trained people can produce an immediate energy store when supplementing creatine such as is otherwise achieved by top athletes on normal nutrition by means of speed and power training. The publications so far available indicate that creatine accumulation in muscle was accomplished using relatively high doses (20 g daily over 5 d). The objective of our study was to investigate the alterations in creatine and creatinine concentrations following lower dosages. METHODS: As intermediate and finishing spurts under anaerobic conditions are gaining in importance in endurance sports, we created a special exercise test for triathletes combining endurance and interval performance. After a pretreatment exercise test was performed, the athletes ingested 6 g of creatine daily, divided into two portions for 5 d. On day 6, another exercise test was performed. RESULTS: Creatine supplementation was found to have no influence on the cardiovascular system, oxygen uptake, and blood lactate concentration. The fall in blood glucose during the exercise test was significantly reduced after consumption of creatine. Although interval power performance was significantly increased by 18%, endurance performance was not influenced. CONCLUSIONS: We conclude that creatine supplementation at doses of 6 g daily has positive effects on short-term exercise included into aerobic endurance exercise.

Administration, Oral↗

PubMed1998

[Stretching--possibilities and limits].

The basic scientific knowledge about stretching remains incomplete in spite of its wide use in sports and physiotherapy. This article deals with the assessment of the flexibility and with the anatomical and physiological basis and limitations of stretching. The effects of stretching on delayed onset muscle soreness (DOMS), performance and regeneration are discussed. Recommendations are given for stretching as a measure of warming-up and cooling-down, for stretching before exercises, which demand explosive maximum muscle strength, and for stretching after training for strength endurance.

Humans↗

PubMed1997

High telomerase activity in primary lung cancers: association with increased cell proliferation rates and advanced pathologic stage.

BACKGROUND: Telomerase enzyme activity is not detected in most normal cells, a phenomenon believed to be associated with limitations on cellular proliferation. Since this activity is detected in nearly all human tumors, including non-small-cell lung cancers, it has been suggested that telomerase activation may be coupled to acquisition of the malignant phenotype. In this study, we determined whether telomerase activity was associated with tumor pathologic stage, tumor cell proliferation rates, and clinical outcome in a cohort of patients with resected non-small-cell lung cancer for whom long-term follow-up was available. METHODS: Primary tumor specimens from 99 patients treated with surgery alone and six patients treated with surgery after chemotherapy were analyzed. Telomerase activity was measured by means of a modified Telomeric Repeat Amplification Protocol (TRAP) assay. Southern blot analysis of terminal restriction fragments was used to evaluate telomere length. Immunohistochemical analysis of Ki-67, a proliferation-associated nuclear antigen, was used to assess tumor cell proliferation. RESULTS: Telomerase activity was detected in 84 of the 99 tumors treated with surgery alone; this activity was not detected in specimens of adjacent, benign lung tissue. Telomerase was detected in only three of six tumors resected after chemotherapy. For the surgery-alone group, statistically significant positive associations were found between the level of telomerase activity and tumor stage, lymph node metastasis, pathologic TNM (tumor-node-metastasis) stage, and Ki-67 immunostaining; a statistically significant inverse association was found between telomerase activity and patient age. No statistically significant differences in telomere length were found in relation telomerase activity or pathologic stage. Telomerase activity was not found to be associated with clinical outcome in a multivariate Cox proportional hazards analysis adjusted for tumor stage and lymph node status. CONCLUSIONS: High telomerase activity is detected frequently in primary non-small-cell lung cancers that exhibit high tumor cell proliferation rates and advanced pathologic stage.

Adenocarcinoma↗

PubMed1997

Telomerase regulation, cell cycle, and telomere stability in primitive hematopoietic cells.

Low levels of telomerase activity have recently been detected in human primitive hematopoietic cells, however, blood cells exhibit telomere shortening on cell proliferation. This challenging observation led us to study telomerase regulation and telomere length in human hematopoietic progenitor cells from fetal liver (FL), cord blood (CB), peripheral blood (PB), and bone marrow (BM). We found telomerase activity in CD34+/CD38+ cells exceeding levels in CD34+/CD38-, CD34- , and mononuclear cells (P < .05). Baseline telomerase activity was highest in BM (n = 5) CD34+ cells, followed by PB (n = 20), CB (n = 11), and FL (n = 1). Within 48 hours to 72 hours of in vitro culture of CD34+ cells in the presence of cytokines (KL, interleukin-3 [IL-3], IL-6, erythropoietin, granulocyte colony-stimulating factor), telomerase activity was upregulated, peaked after 1 week of culture, and decreased to baseline levels or below detection after 3 to 4 weeks. Stimulation of CD34+ cells with single cytokines resulted in no or minor telomerase upregulation, whereas cytokine combinations resulted in a significant telomerase increase (P < .001). There was a correlation between telomerase activity, cell cycle status by BrdU incorporation, and induction of phosphorylated retinoblastoma protein, CDC2, CDK2, cyclin D1, and cyclin A, but not cyclin E and B1 after 72 hours with multiple (but not single) cytokines. In nonexpanding CD34+ cells, telomerase was low or undetectable. Secondary CD34+ cells showed a reduced ability to upregulate telomerase activity. Antiproliferative cytokines such as transforming growth factor-beta1 and high concentrations of all-trans-retinoic acid in cytokine-supported CD34+ cultures downmodulated telomerase activity. Average telomere lengths were 10.4 kbp, 7.4 kbp, and 7.6 kbp in CB, PB, and BM CD34+ cells, respectively. In ex vivo expansion cultures, an average telomeric DNA loss of 1 to 2 kbp over 4 weeks was observed. However, the rate of base pair loss per population doubling was significantly lower during the first 2 weeks, when telomerase was upregulated, than during weeks 3 and 4 of culture. In summary, telomerase is upregulated in response to cytokine-induced proliferation and cell cycle activation in primitive hematopoietic cells. Telomerase is downregulated between weeks 3 and 4 of ex vivo expansion culture linked with decreased proliferation and greater expansion of more mature cell subsets. Our data suggest that telomerase activity in hematopoietic cells reduces, but does not prevent, telomere shortening on proliferation.

Antigens, CD34↗

PubMed1997

[Spondylolysis and spondylolisthesis and sports].

Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.

Adult↗

PubMed1997

Clinical and immunomodulatory effects of repetitive 2-day cycles of high-dose continuous infusion IL-2.

High-dose interleukin-2 (IL-2) treatment has demonstrated promising antitumour activity in renal cell carcinoma (RCC) and malignant melanoma (MM) and has been shown to induce broad immunological effects. The optimal IL-2 dose and schedule, however, still remain to be defined. We studied a treatment protocol consisting of five repetitive cycles of high-dose recombinant (rh) IL-2 (24 x 10(6) U/m2/day) administered weekly on two consecutive days by continuous intravenous infusion. 17/19 were RCC patients, 2 of whom responded with a complete remission (CR) and 3 with a partial response (PR) (CR + PR: 29%; median response duration of 11.5+ months (range: 3-14 months)). IL-2 induced a pronounced increase of lymphocytes and pro-inflammatory cytokines IL-8, IL-5, gamma-IFN, TNF- alpha and TNF-beta (p < 0.05) that peaked in cycle 3. With subsequent therapy, serum levels of these cytokines, NK, T cells and eosinophils decreased, whereas serum IL-10 levels progressively increased with maximum levels achieved after the fifth week of treatment, suggesting that it may be involved in dampening the inflammatory response induced by IL-2. Absolute numbers of activated T cells and NK cells remained elevated as compared to baseline for at least 4 weeks after treatment cessation. Based on these observations, future scheduling of IL-2 will be done at 3 weekly 2-day cycles separated by a week 4 treatment-free interval in order to increase further the 29% objective response rate achieved in this study.

Adult↗

PubMed1997

Blood progenitor cell (BPC) mobilization studied in multiple myeloma, solid tumor and non-Hodgkin's lymphoma patients after combination chemotherapy and G-CSF.

For blood progenitor cell (BPC) mobilization, standard-dose VIP chemotherapy consisting of etoposide, ifosfamide and cisplatin has previously shown effective tumor reduction in solid tumor patients and sufficient progenitor cell mobilization for autologous blood cell transplantation. Mobilization chemotherapy regimens in multiple myeloma (MM) predominantly consist of melphalan or cyclophosphamide that induce marked cytopenia and considerable variability of progenitor cell collection. We studied whether in MM (n = 13), BPCs were efficiently and reproducibly mobilized with etoposide (500 mg/m2) and ifosfamide (1500 mg/m2), followed by daily s.c. G-CSF (5 micrograms/kg). In parallel, patients with solid tumors or non-Hodgkin's lymphomas (n = 28) treated with etoposide (500 mg/m2), ifosfamide (1500 mg/m2) and cisplatin (150 mg/m2) and identical dosing of G-CSF were analyzed. Before chemotherapy (day 0), on day 7 after chemotherapy and on days of leukapheresis (day 9-14), leukocyte numbers, mononuclear cells (MNCs), CD34+ cells and coexpression of lineage markers were analyzed. Median blood leukocyte numbers were 28,100/microliters (range, 19,600-40,400) on day 10 in myeloma patients and progressively declined over the next 4 days. In contrast, in solid tumor and lymphoma patients leukocyte numbers constantly increased from a median of 12,400/microliters (range, 6000-22,000) to 30,000/microliters (range, 16,300-63,300) between day 10 and day 13 after chemotherapy. Similar to leukocyte counts, median MNC numbers decreased in myeloma patients with successive leukaphereses, but steadily increased in solid tumor and lymphoma patients over the same period. CD34+ cell numbers in the blood peaked between day 9 and 11 (median: 40/microliters) in myeloma patients and then declined. In the solid tumor and lymphoma group, median CD34+ counts in the blood peaked on day 12 after mobilization chemotherapy (median: 100/microliters). The median CD34+ yield per leukapheresis in the myeloma group was 2.2 x 10(6)/kg (range, 1.5-4.7) on day 10, and fell steadily to 0.95 x 10(6)/kg on day 12, whereas in solid tumor/NHL patients median CD34+ cell yields remained between 3.5 and 3.7 x 10(6)/kg from day 10 to day 12 after mobilization chemotherapy (P < 0.001). To obtain sufficient cell numbers for engraftment a median of 2 (range, 1-3) mobilization chemotherapy cycles were needed in MM compared to 1 (range, 1-10) in solid tumor or lymphoma patients, with a median of 5 (range, 2-8) leukaphereses in MM compared to 1 (range, 1-10) (P < 0.05). Taken together, we found that for patients with MM, VP16 and ifosfamide efficiently and predictably mobilizes progenitor cells into the PB with > or = 3 x 10(6)/kg CD34+ cells collected after one to two mobilization chemotherapy cycles.

Adult↗

PubMed1997

[Electromyography-controlled muscle rehabilitation--knee injuries].

Surface is a noninvasive, mostly nonreactive, objective measuring procedure for evaluation of the degree of muscle activation. It allows for accurate assessments of the neuromuscular system and description of adaptations resulting from injury. Decreases in torque, EMG amplitude and EMG frequency occur as a result of knee joint injuries. Efficiency checks and evaluations of training programs and neuromuscular treatment can be done. Decreases in torque, EMG amplitude and EMG frequency found after knee joint injury (cruciate ligament, meniscus) are due to intraarticular and periarticular afferent processes. 12 weeks postoperatively, the neuromuscular deficits from cruciate ligament injury have increased. While complete recovery can be achieved following meniscus fixation (more than 1 year postoperatively), cruciate ligament injuries lead to chronically reduced EMG median frequencies.

Athletic Injuries↗

PubMed1997

[The nerve supply of the knee joint].

The paper presents the present state of research on the most important receptors of joints and muscles with regard to occurrence, structure, and function. Proprioception relies on the nervous supply of the tissues in the knee joint, and on the surrounding muscles and tendons; it is the basis of coordination.

Afferent Pathways↗

PubMed1997

[Indications and surgical procedures in meniscus and capsular ligament injuries].

The main aim in the treatment of meniscus injuries is the restoration of the meniscus by a primary suture. Partial resections of the meniscus should be done in a sophisticated arthroscopic technique. By the reason of relaxing of the joint's ligament should be repaired by operation. In spite of a larger "defect" bone-tendon-bone techniques are to prefer because of an improved long-term stability.

Arthroscopes↗

PubMed1997

[Therapeutic physical training after knee injuries].

Exercise training is a therapy that accompanies and follows physiotherapy. Basic training principles are discussed on the basis of motricity research. Initially, exercise therapy mostly trains patients to recall and standardize the execution of exercise programs. With the patient's increasing power of endurance, the intensity of extent of training are increased. Exercise therapy eventually aims at particularly preparing the patient for the activities of daily living and the sportsman for the requirements specific to training and competition.

Combined Modality Therapy↗

PubMed1997

[Treatment with physical therapy after knee injuries].

Trauma to the inner knee disturb the organism's local and central regulations. Physiotherapeutic measures stimulate self-regulatory and self-regenerative mechanisms of the organism. Depending on the specific needs of the patient, active exercise treatment, or various procedures of physical therapy are administered (hydro and thermotherapy, electromedicine, light therapy, aerosol therapy, balneology, and climatology) in order to achieve his/her full restoration to the maximal potential vocationally, socially, and physically.

Combined Modality Therapy↗