Effect of a silver device in preventing catheter-related infections in peritoneal dialysis patients: silver ring prophylaxis at the catheter exit study.

Catheter-related infections remain a significant cause of method failure in chronic peritoneal dialysis (PD) therapy. Given the increasing antibiotic resistance, such nonpharmacological strategies as local silver devices attract more interest. To establish whether a silver ring device (designed by Grosse-Siestrup in 1992) mounted onto the PD catheter and placed at the exit site at skin level is effective in preventing exit-site and other catheter-related infections, a prospective 12-month, multicenter, controlled study stratified by diabetes status was conducted. The study subjects were assessed by an extensive structured inventory, including a broad spectrum of control variables, such as age, body mass index (BMI), Staphylococcus aureus carrier status, catheter features, mode and quality of PD therapy, comorbidity, and psychosocial rehabilitation. Ten experienced German outpatient dialysis centers (seven adult, three pediatric) participated in the trial. All eligible patients (n=195) from the study area without catheter-related infections during the ascertainment period were included (incidental subjects undergoing PD therapy for at least 3 months). The main outcome measures were the occurrence of first exit-site infections (primary study end point), sinus tract/tunnel infection, and peritonitis. Ninety-seven patients were assigned to the silver ring and 98 patients to the control group. Baseline characteristics of age, sex, proportion of pediatric and incidental patients, S aureus carrier status, and other variables were similar in both groups. The incidence of infections in the silver ring group versus the control group was as follows: 23 of 97 versus 16 of 98 patients had exit-site infections, 12 of 97 versus 12 of 98 patients had sinus tract/tunnel infections, 16 of 97 versus 18 of 98 patients had peritonitis, respectively. Kaplan-Meier analysis for the probability of an infection-free interval showed no statistical difference (log-rank test) between the two groups. Displacement of the silver ring contributed to study termination in 6% of the study group patients, including two patients with catheter loss. Univariate analysis and multiple logistic regression identified younger age (<50 years), low serum albumin level (<35 g/L), number of previously placed PD catheters, short cuff-exit distance (<2 cm), and S aureus nasal carriage as risk factors for the development of exit-site infections. In conclusion, our study does not show any benefit of the silver ring in preventing catheter-related infections in PD patients. Thus, prevention of infection-related method failure in PD still has to rely on conventional antibiotic treatment strategies and less so on alternative methods.

Is laser assisted angioplasty a real alternative to surgical treatment of occluded peripheral vessels?

Since 1988 250 patients had occluded peripheral arteries reopened by an Argon laser. The mean age of the 110 men and 85 women was 71 years and the mean length of all occlusions 13.4 cm. The primary success rate was 81.5% with a perforation rate of less than 2%. The patency rate after 96 weeks was 80%.

Comparative studies on the polyamine metabolism and DFMO treatment of MCF-7 and MDA-MB-231 breast cancer cell lines and xenografts.

In order to characterize the estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cells and xenografts, their growth kinetic parameters and some biochemical characteristics concerning the receptor status and polyamine metabolism were determined and compared. The doubling times calculated from the growth curves showed higher proliferation rate of MDA-MB-231 cells, both in culture (21 hours) and in xenograft (9.7 days), in comparison to the MCF-7 cells which had values of 32 hours and 11.6 days, respectively. Growth-dependent changes observed in the intracellular putrescine, spermidine and spermine concentrations indicated a higher activity of polyamine metabolism in the MDA-MB-231 cells and xenograft as well. However, biosynthetic key-enzyme ornithine decarboxylase activity (ODC, EC 4.1.1.17) showed neither characteristic differences between the two types of breast cancer, nor consistent relationship with their proliferation rate. Metabolic alterations of the MCF-7 and MDA-MB-231 cell lines grown in vitro were also reflected in the polyamine composition of their culture medium. Independently of their receptor status, both types of breast cancer were responsive to difluoromethylornithine (DFMO) treatment. DFMO inhibited the ODC activity totally and depleted the cellular polyamine levels. MCF-7 cells in culture were more sensitive to the antitumoral effect of DFMO than the MDA-MB-231 line, while the rate of growth inhibition did not differ significantly in the xenografts. The present results provided further evidence on the different polyamine metabolism of ER-positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cells in vitro and in vivo, suggesting a correlation of hormonal modulation with polyamines as a determinant group of biological response modifiers.

[Quantitative flow measurement of the art. dorsalis pedis in normal probands and patients with arterial occlusive disease of a low Fontaine stage]. / Quantitative Flussmessungen der Art. dorsalis pedis bei Normalprobanden und AVK-Patienten niedriger Fontaine-Stadien.

Quantitative blood flow measurements of the dorsal foot artery were performed with a multichannel digital pulsed Doppler device in normal volunteers and in patients with Fontaine IIa stage peripheral arterial occlusive disease. The measured parameters were: 1. vessel diameter, 2. maximum systolic flow volume, 3. minimum diastolic flow volume, 4. maximum systolic velocity, 5. minimum diastolic velocity. The calculated parameters were: pulsatility index, mean velocity and mean flow volume. Pulsatility index, maximum systolic flow volume and velocity were found to be reduced--although not statistically significant--in patients compared to volunteers.

[Initial experiences with transpopliteal, laser-assisted balloon angioplasty of femoral artery occlusions]. / Erste Erfahrungen mit der transpoplitealen laserassistierten Ballonangioplastie bei Femoralisverschlüssen.

For many years great efforts are being made to recanalise totally occluded vessels and averting a bypass operation as long as possible. In two years 190 patients were treated successfully by the Lastac System. Encouraged by very good results, we started to recanalise the totally occluded superficial femoral artery via a transpopliteal approach. Meanwhile, 29 patients were treated. Primary successful were 22 patients with an average length of a total occlusion of 27.5 cm.

[Recanalization of peripheral vascular occlusions using an argon laser]. / Rekanalisation peripherer Gefässverschlüsse mit einem Argonlaser.

A new Argonlaser developed in the United States of America is available to the radiological and surgical departments of the Hospital of St. Pölten. It is used for recanalization of totally occluded peripheral arteries. During the last 9 months, 51 patients (30 men and 21 women) with an average age of 71 years have been treated. Total occlusion was present in 88% of the arteries treated. The primary success rate is 89%, and the perforation rate is under 2%.

Changes in the polyamine and nucleotide metabolism of P388 leukemia cells treated with DL-alpha-difluoromethylornithine in culture.

Influence of DL-alpha-difluoromethylornithine (DFMO) treatment on the growth kinetics, labelling index, extra- and intracellular polyamine and nucleotide concentrations was monitored in cultured P388 leukemia cells. A substantial decrease of cell proliferation was observed when the cells were continuously treated with 1-5 mM DFMO. Depletion of cellular polyamines, mostly of putrescine and spermidine, was seen with a concomitant but delayed increase of spermidine and spermine levels in the culture medium. Changes of DNA content and of labelling index of untreated and treated cells seem to indicate that DFMO arrested cells in G1/S transition. The results presented here provide additional in vitro evidence on the characteristic changes in the metabolic imbalance of ornithine in tumor cells induced by DFMO via inhibition of ornithine decarboxylase and ornithine carbamoyl transferase activities.

Permanent metachromatic effect of 1,9-dimethyl-methylene blue on acidic mucopolysaccharides of mastocytes.

The 1,9-dimethyl-methylene blue (SERVA) has a very strong metachromatic reaction with sulphated mucopolysaccharides of mastocytes at pH = 1 (Tris-HCl buffer). This metachromasia is retained also at increasing pH (2.5-5), and is not affected either by the quality or by the concentration of the ions present (1/240 M Tris-HCl, and 0.2 M phosphate buffer). The smears do not need any special mounting medium, only Canada balsam. The metachromasia is preserved for a considerable length of time.

Cytochemical characterization of Yoshida sarcoma cells resistant to dibromodulcitol.

Two Yoshida ascites sarcoma cell populations, one of them originally sensitive and another rendered resistant to the alkylating agent dibromodulcitol (DBD), were compared for doubling time, labeling index, survival time, morphological features, cellular DNA content and modal DNA value. Cross-resistance studies were carried out on bilaterally growing solid tumours derived from the sensitive and resistant Yoshida cell populations. Glycogen-containing granules appeared in the cytoplasm of the DBD-resistant sarcoma cells; these were not present in the sensitive tumour. The growth parameters of the sensitive tumour were throughout the 10-day observation period characteristic of rapidly proliferating tumours, whereas those of the DBD-resistant tumour was characteristic of slowly proliferating systems. As compared to the mean DNA values for normal somatic cells (lymphocytes), those found for both tumours indicated that the cells were hyperdiploid aneuploid. The DNA stem line in the resistant tumour proved to be significantly smaller than that in the sensitive tumour. These results indicate that a reduction of malignancy in the Yoshida tumour is associated with a developed resistance to dibromodulcitol. The resistant tumour showing cross-resistance to dianhydrogalactitol, diacetyl-dianhydrogalactitol and to nitrogen mustard retained full sensitivity to cyclophosphamide and adriablastin (Adriamycin), and proved to be collaterally sensitive to vincristin.

The effect of N-formylleurosine on DNA synthesis of Ehrlich ascites tumor.

Some of the vinca alkaloids are well known and widely used in clinical practice, in spite of their numerous side-effects. For the elimination of untoward side-effects semi-synthetic alkaloids have been produced. This work reports on N-formylleurosine (N-F-Leu), one of these agents. Its antitumour activity is, in many respects, similar to that of other, presently used vinca alkaloids; it causes metaphase block, the appearance of multinucleated cells and polyploidization. In addition to these effects, N-F-Leu induces significant new phenomena, namely, changes in the activity of thymidine kinase, a key enzyme of DNA synthesis as well as in thymidine incorporation, and reduces the proportion of cells in S phase in a relatively short period of time after treatment: 24-29 hr. Based on these observations, the reevaluation of the mechanism of action of vinca alkaloids has become possible.

Study of the antitumoral activity of S-carbamoyl-L-cysteine derivatives in animal experiments.

The antitumoral activity of three amino acid derivatives, S-carbamoyl-L-cysteine, S-ethyl-carbamoyl-L-cysteine, and S-chloroethyl-carbamoyl-L-cysteine, was studied. The ethyl and chloroethyl derivatives had a pronounced curative effect on certain animal tumors. It is interesting in the case of S-carbamoyl-L-cysteine that N-ethylization of the substance resulted in increased chemotherapeutic effectivity with no simultaneous change of the toxicity. According to various studies this effect is different in many respects from that of the known cytostatics, and a possibility of a specific selective or surface activity is raised.

Cytophotometric determination of basic proteins with heparin-alcian blue method.

For the quantitative cytochemical determination of basic proteins, Heparin-Alcian Blue (HAB-was found to be a more suitable staining procedure than the generally used alcalic Fast green reaction. HAB is able to stain all the histone fractions, but there is no staining following deamination (gelelectrophoretic examinations) and no aspecific staining (Millipore filter model). In EHRLICH ascites tumour cells, changes in the FEULGEN-DNA content is followed by the proportional changes of HAB-basic protein content. After HAB reaction, the FEULGEN reaction can be performed on the same slide.