Five-day storage of platelets in a non-diethylhexyl phthalate-plasticized container

A non-diethylhexyl phthalate (DEHP)-plasticized blood bag for 5-day storage of random-donor platelet concentrates has been developed. The plastic bag is composed of polyvinylchloride plastic with a butyryl trihexyl citrate plasticizer. The suitability of this plastic for the storage of platelet concentrates for use in clinical transfusion practice was evaluated. In vitro storage studies showed no significant differences at Day 5 for a series of in vitro assays (test plastic vs. control plastic) including pH (7.31 vs. 7.44), lactate dehydrogenase discharge (21.8 vs. 17.1%), pO2 (103 vs. 120 torr), osmotic recovery (52 vs. 57%), and morphology score (527 vs. 516). For paired radiolabeled recovery and survival data from autologous blood donors, results showed equivalence between the test plastic and two control plastics. A small but significant difference between test and control plastics in regard to survival was found by using a linear computer model, but not with a gamma function (multiple-hit) model. For paired transfusions to thrombocytopenic patients, the corrected count increments at 1 to 4 hours (test vs. control) were 13,534 versus 15,494 (p > 0.05, NS). Similar results were seen for corrected count increments determined at 12 to 24 hours. It can be concluded that platelets stored in the test plastic are acceptable for use in clinical practice.

Storage and transfusion of platelets collected by an automated two-stage apheresis procedure

Platelets collected by using a two-stage automated blood cell separator were evaluated after 5 days of storage. The procedure caused no unanticipated physiologic changes in donors and produced greater than 3 x 10(11) intact platelets in 200 mL of plasma, plus an additional 400 mL of plasma with intact coagulation factors. Posttransfusion recovery of autologous radiolabeled platelets was comparable to that seen in platelets prepared by manual centrifugation techniques. Corrected count increments in 14 patients showed results similar to those with control transfusions. This device, which involves a collection time of less than 90 minutes, provides an option for platelet-pheresis in a variety of settings including blood mobiles.

Preoperative irradiation for unresectable rectal and rectosigmoid carcinomas

The records of 25 patients with unresectable carcinoma of the rectum and rectosigmoid who received preoperative radiation therapy (RT) were reviewed. Twenty patients were considered to be resectable following RT (80%). Sixteen patients (64%) underwent curative resections. All patients with unresectable tumors following RT died with tumor within two and one half years (median survival, 11 months). For patients undergoing curative resection, the probability of two- and five-year survival was 56% and 43%, respectively. In this latter group, five of seven patients with treatment failures (71%) had a pelvic component of disease. The incidence of pelvic recurrence was correlated with the pathologic stage, extent of resection and preoperative radiation dose. The need for more aggressive treatment for patients with these advanced tumors is emphasized. Future treatment alternatives are discussed.

Antibacterial structure-activity relationships obtained with resistant microorganisms I: Inhibition of R-factor resistant Escherichia coli by tetracyclines

Aparent partition coefficients and inhibitory activities against sensitive and resistant Escherichia coli were determined for 14 tetracyclines. The difference in the kinetics of inhibition of the two organisms is discussed in terms of their permeabilities. The partition coefficients were determined in an octanol-buffer system. Values for eight compounds were in general agreement with the literature; values for the remaining six compounds had not been reported previously. Growth of the organisms was determined by a single-point turbidimetric method in the presence and absence of tetracyclines. Inhibitory activities were obtained by a kinetic treatment. Derived rate constants for the sensitive organism were linearly related to antibiotic concentration. For the resistant organism and 12 compounds, the derived rate constants and antibiotic concentration were related in a manner typical of saturation kinetics. These inhibitory activities were related to the partition coefficients, while activities against the sensitive strain were not. These findings suggest that activity against the resistant strain is permeability controlled but that activity against the sensitive strain has a different rate-determining step.