Primary Open Versus Closed Implantation Strategy for Totally Implantable Venous Access Ports: The Multicentre Randomized Controlled PORTAS-3 Trial (DRKS 00004900).

OBJECTIVES: PORTAS-3 was designed to compare the frequency of pneumothorax or haemothorax in a primary open versus closed strategy for port implantation. BACKGROUND DATA: The implantation strategy for totally implantable venous access ports with the optimal benefit/risk ratio remains unclear. METHODS: PORTAS-3 was a multicentre, randomized, controlled, parallel-group superiority trial. Adult patients with oncological disease scheduled for elective port implantation were randomized to a primary open or closed strategy. Primary endpoint was the rate of pneumothorax or haemothorax. Assuming a difference of 2.5% between the 2 groups, a sample size of 1154 patients was needed to prove superiority of the open group. A logistic regression model after the intention-to-treat principle was applied for analysis of the primary endpoint. RESULTS: Between November 9, 2014 and September 5, 2016, 1205 patients were randomized. Of these, 1159 (open n = 583; closed n = 576) were finally analyzed. The rate of pneumothorax or haemothorax was significantly reduced with the open strategy [odds ratio 0.27, 95% confidence interval (CI) 0.09-0.88; P = 0.029]. Operation time was shorter for the closed strategy. Primary success rates, tolerability, morbidity, dose rate of radiation, and 30-day mortality did not differ significantly between the groups. CONCLUSION: A primary open strategy by cut-down of the cephalic vein, if necessary enhanced by a modified Seldinger technique, reduces the frequency of pneumothorax or haemothorax after central venous port implantation significantly compared with a closed strategy by primary puncture of the subclavian vein without routine sonographic guidance. Therefore, open surgical cut-down should be the reference standard for port implantation in comparable cohorts. TRIAL REGISTRATION: German Clinical Trials Register DRKS 00004900.

Clinical and microbiological status of osseointegrated implants.

Peri-implantitis, an inflammatory response around implants, has a poorly defined etiology and pathogenesis. To better understand the role of specific microorganisms in this disease process, clinical and microbiological parameters were examined in 24 patients with 98 osseointegrated implants. Sites were evaluated for probing depth (PD), plaque/calculus index (PI), gingival bleeding index (GBI), mobility, and crevicular fluid flow rate (CFFR). Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in subgingival plaque were identified by latex agglutination assays. Clinically, a statistically significant correlation (P < 0.001) was observed between probing depth and the length of time an implant was present. Mobility was also significantly greater (P < 0.001) in the maxillary than in the mandibular implants. Subgingival sites harboring one of the three microorganisms had significantly greater PD, GBI, and CFFR than non-colonized sites. Implants in partially edentulous patients more frequently were colonized with P. gingivalis/P. intermedia than edentulous patients. The incidence of these microorganisms also correlated with fixture longevity. Implants present for 3 to 4 years had a significantly greater frequency of test microorganisms than implants present for 1 to 2 years. These findings suggest that microbial pathogens associated with periodontitis occur more commonly around implants exhibiting gingival inflammation (GBI) and may contribute to peri-implantitis.

Monoamine oxidase in rat reticulocytes: subcellular localization and identification of isoenzymes.

After "chemically induced reticulocytosis" in rats by treatment with acetyl-phenylhydrazide, monoamine oxidase (MAO) activities were determined in erythrocyte preparations of these animals. Studies on subcellular fractions obtained by differential centrifugation showed that the enzyme activity of rat reticulocytes is a classical mitochondrial MAO. The patterns of inhibition produced by clorgyline (A-type MAO), deprenil (B-type MAO) and pargyline or tranylcypromine (both types of MAO) in reticulocytes were determined in vitro using tryptamine as a substrate for both types of MAO and phenylethylamine as a substrate for the B-type. The results indicate that both A-type (approximately 75%) and B-type (approximately 25%) MAO are present in rat reticulocytes; while tryptamine was mainly deaminated by the A-type enzyme, both types of MAO were shown to contribute to the deamination of phenylethylamine. These findings were confirmed in investigations on the thermostabilities of the tryptamine and phenylethylamine deaminating activities of rat reticulocyte MAO.