Biomedical subjects

M Mempel

Publications and source records attributed to M Mempel.

46 records · Page 3Linked to original sources

PubMed1995

Variable degree of slime production is linked to different levels of beta-lactam susceptibility in Staphylococcus epidermidis phase variants.

Recently we demonstrated that lack of mecA transcription was responsible for the decreased methicillin resistance phenotype of strongly slime-negative Staphylococcus epidermidis phase variants [Mempel M, Feucht H, Ziehbuhr W, Endres M, Laufs R, Grüter L (1994) Antimicrob Agents Chemother 38: 1251-1255]. In the present study we compared the beta-lactam susceptibility and the slime production capacity of 60 phenotypic variants of S. epidermidis parent strain RP62A identified by their colony morphology on congo red agar. We could show that the variable degree of slime production is linked to different levels of beta-lactam susceptibility in intermediate-stage phase variants. The increased deltahemolysin production of slime-negative phase variants may indicate an accessory gene regulator-like control.

Anti-Bacterial Agents↗

PubMed1995

Osteosynthetic reconstruction in a patient with Gardner-Diamond syndrome.

Based on clinical observations in one female patient who suffered from Gardner-Diamond syndrome, we noticed that surgery can be performed without any bleeding complications, although operations normally are contraindicated in persons with this condition. Additionally, a correlation seems to exist between ASS and sexual and hormonal maturity.

Autoimmune Diseases↗

PubMed1994

Lack of mecA transcription in slime-negative phase variants of methicillin-resistant Staphylococcus epidermidis.

Five phase variants (PV1 to PV5) of the well-characterized, slime-producing, methicillin-resistant, pathogenic strain of Staphylococcus epidermidis sensu strictu RP62A (ATCC 35984) were isolated by the Congo red agar method. In comparison with the parent strain, the phase variants showed a different colonial morphology on Congo red agar, a strongly reduced adherence capacity, and decreased levels of resistance to methicillin, oxacillin, and penicillin. All phase variants yielded biochemical reaction patterns and profiles in pulsed-field gel electrophoresis identical to those of parent strain RP62A, indicating a common origin. All phase variants proved to have the capacity to shift back to the original phenotype of parent strain RP62A. A search for the resistance mechanisms of strain RP62A revealed beta-lactamase production and the presence of mecA in PV1 to PV5 as well as parent strain RP62A. In Northern blots of total staphylococcal RNA, the phase variants showed no detectable mecA-specific transcription product, whereas parent strain RP62A revealed a strong signal, indicating that mecA transcription is not the mechanism responsible for the decreased methicillin resistance phenotype of phase variants PV1 to PV5.

Anti-Bacterial Agents↗

PubMed1994

Blood transfusion-modulated tumor recurrence: first results of a randomized study of autologous versus allogeneic blood transfusion in colorectal cancer surgery.

PURPOSE: Allogeneic blood transfusions have reportedly been associated with a poor prognosis in patients with curatively resected cancer. To control for immunosuppression induced by a speculatively causal allogeneic blood transfusion, we designed a randomized study in which the control group received autologous blood transfusions not related to any condition of immunosuppression. PATIENTS AND METHODS: One hundred twenty patients with potentially curative resectable colorectal cancer and the capability to predeposit autologous blood were randomly selected to receive either standard allogeneic blood transfusion or predeposited autologous blood. RESULTS: In curatively resected cancer patients, the number who needed allogeneic blood transfusions was reduced from 60% in the allogeneic blood group to 33% in the autologous blood group (P = .009). After a median follow-up duration of 22 months (range, 8 to 48) tumor recurrence was observed in 28.9% of the allogeneic blood group and 16.7% of the autologous blood group. Life-table analysis established a tendency toward a shorter tumor-free survival for the allogeneic blood group (log-rank P = .11). The problem with this analysis was the strong association of allogeneic blood transfusions with tumor recurrence, which interfered in 33% of patients in the autologous blood group who required additional allogeneic blood transfusions. Multivariate analysis of established risk factors for tumor recurrence and surgery-related variables reflecting potential immunosuppressive conditions showed that only pT stage (relative risk, 6.61; 95% confidence interval [CI], 1.82 to 23.99; P = .004), pN stage (relative risk, 8.39; 95% CI, 3.15 to 22.33; P < .001), and the need for allogeneic blood (relative risk, 6.18; 95% CI, 2.20 to 17.37; P < .001) were independent predictors of tumor recurrence. Subgroup analysis of patients who received a transfusion of < or = 2 U blood found a significantly higher risk of tumor recurrence in the allogeneic blood group (relative risk, 5.16; 95% CI, 1.13 to 23.62; P = .034), which was reduced to borderline significance (relative risk, 3.54; 95% CI, 0.76 to 16.51; P = .107) by adjustment for tumor (T) and node (N) stage. CONCLUSION: As indicated by these first results, the blood transfusion modality has a significant effect on tumor recurrence after surgical treatment of colorectal cancer. A change in the practice of blood transfusion might thus potentially surpass the impact of any recent adjuvant treatment strategies.

Aged↗

PubMed1993

Beneficial effect of autologous blood transfusion on infectious complications after colorectal cancer surgery.

Homologous blood transfusion has been associated with an increased risk of postoperative infectious complications. To test the clinical consequences of this apparently immunosuppressive effect of homologous blood in a controlled trial, we designed a study in which the control group deposited autologous blood before their operations for use should transfusion be needed. We enrolled 120 patients with apparently curable colorectal cancer who were able to predeposit autologous blood (haemoglobin > 12.5 g/dL). 62 patients were assigned to receive homologous blood if blood transfusions were needed during operation, and the other 58 to receive their own predeposited blood followed, if necessary, by homologous blood [corrected]. Despite the similarity between the groups in factors known to affect the risk of postoperative infections, there was a significant difference in postoperative infection rate between the homologous and autologous blood groups (17 [27%] vs 7 [12%], p < 0.05; unadjusted odds ratio 2.75 [95% CI 1.07-7.11). The rates of non-infectious complications were similar Probably because their preoperative blood depositing caused the autologous blood patients to have lower haemoglobin concentrations, they were more likely to require transfusion than were the homologous blood group (53 [91%] vs 37 [60%], p < 0.001; relative risk 1.53 [1.24-1.89]). 20 (35%) required homologous as well as autologous blood. To adjust for the many infection-related factors, we did multivariate regression analysis; tumour location, preoperative ASA index, and study group assignment were the only significant risk factors. The odds ratio for postoperative infections adjusted for these factors was 2.84 (1.02-7.98, homologous vs autologous). Testing of delayed-type hypersensitivity responses before and after surgery showed decreases in both mean diameter and number of positive reactions in recipients of homologous blood and slight increases in those who received autologous blood. This study shows the clinical potential of blood-transfusion-mediated immunomodulation, which may be important also in tumour immunology.

Adenocarcinoma↗

PubMed1993

Effects of recombinant human erythropoietin on autologous blood donation before open heart surgery.

We studied the effects of four different doses of recombinant human erythropoietin (rhEPO) on the amount of preoperative autologous blood donation. 43 patients prior to open heart surgery were randomized into 5 groups (100, 200, 400, 800 U/kg rhEPO i.v. or placebo) and treated twice weekly over a period of 4 weeks. Autologous blood was taken at a hemoglobin of 13 g/dl and a hematocrit of 34% respectively. Application of low-dose rhEPO (100 and 200 U/kg) did not increase the amount of autologous blood donated, only 400 and 800 U/kg produced a significant increase by 27% and 39% respectively (p < 0.01) In addition RBC showed a reduced decline of hemoglobin level (p < 0.01). Reticulocytes increased by 2.5 times the baseline in the placebo and treatment groups up to 200 U/kg. Again, only 400 and 800 U/kg produced a significantly higher increase of 3.2 and 3.6 times respectively (p < 0.05 and p < 0.01). Although iron was supplied orally, ferritin levels declined in all groups whereas serum iron and transferrin levels remained unchanged. No influence could be detected on WBC, thrombocyte count, or arterial blood pressure. Mild and reversible side effects were observed in 8 patients (19%). Perioperatively 34 patients (81%) received exclusively autologous blood, only 8 patients (19%) needed additional homologous blood transfusions. Administration of high-dosed rhEPO (400-800 U/kg) seems to be an effective treatment with only slight side effects for increasing erythropoiesis during autologous blood donation.

Adolescent↗

PubMed1993

Construction of a slime negative transposon mutant in Staphylococcus epidermidis using the Enterococcus faecalis transposon Tn917.

The slime-producing Staphylococcus epidermidis strain sensu strictu CNS23 was transformed by protoplast transformation with the plasmid pTV1 which carries transposon Tn 917. Using this transposon mutagenesis system we obtained the Tn917-inserted mutant CT512, which has lost the ability to produce slime. A single insertion of the transposon Tn917 into the chromosome of CT512 could be detected by Southern hybridization. This mutant showed a significantly higher stability concerning its slime-negative phenotype compared with spontaneous slime-negative mutants of S. epidermidis strain CNS23. In slime-ELISA no slime-associated antigen could be detected in extracts of the transposon mutant. Compared to slime-positive S. epidermidis strains, CT512 lacked in accumulative growth in microtiter tube test.

DNA Transposable Elements↗

PubMed1993

[Clinical effects of blood transfusion-associated immune modulation on outcome of tumor surgery].

Extended experimental studies revealed different immunological mechanisms which are possibly responsible for blood transfusion-associated immunosuppressive conditions. To expect a clinical impact of these mechanisms on the course of tumor disease, it is necessary to postulate (1) that immunological mechanisms have a significant role in controlling tumor growth and (2) that blood transfusion-induced immunmodulation is long lasting. Both postulates are supported by recent reports and are the rationales of clinical studies indicating that blood transfusion is a risk factor for postoperative infections and tumor recurrence. Since all studies have been retrospective or uncontrolled, we performed a prospective controlled study in randomized groups of patients suffering from colorectal cancer and compared the effects of allogeneic and autologous blood transfusions. The results indicate that patients treated with allogeneic blood transfusion had significantly higher rates of postoperative infectious complications than patients who received autologous blood. Our preliminary follow-up observations found a trend towards higher tumor-free survival in patients treated with autologous blood which is statistically significant in subgroup analysis.

Adult↗

PubMed1987

[Therapeutic lymphapheresis in leukostasis-induced priapism].

Priapism occurred as a result of leukostasis due to an extreme rise in leukocyte count (503,000/microliter, 96% lymphocytes) in a 46-year-old man with chronic lymphatic leukaemia. In addition to surgical treatment, anticoagulant administration and cytostatic treatment several courses of lymphapheresis were performed using a cell separator. This latter procedure quickly reduced the number of lymphocytes and improved the patient's operability.

Combined Modality Therapy↗

PubMed1985

[Idiopathic thrombocytopenic purpura and pregnancy].

ITP is the most common autoimmune disease during pregnancy. Whereas the maternal risk due to the extreme thrombocytopenia can be calculated, the risk to the foetus is difficult to predict. As there is no correlation between maternal and foetal platelet count, no generalisations can be made as to the preferable method of delivery. The methods of treatment with special reference to pregnancy and the various procedures necessary during delivery are discussed.

Adult↗