Superficial antigens of Campylobacter (Vibrio) fetus: characterization of antiphagocytic component.

A glycoprotein responsible for the antiphagocytic properties of Campylobacter fetus has been identified by comparing cells of a wild-type strain with those of a mutant lacking this substance. The antiphagocytic component is demonstrable through electron microscopy as a discrete, negatively charged structure on the periphery of the cell. CLT is readily removed from the cell by mild extraction procedures and contributes to the inagglutinability in O antiserum normally displayed by C. fetus. Cells possessing this antigen are refractory to ingestion by macrophages except in the presence of specific antiserum. In its absence maximum phagocytosis occurs without a requirement for opsonins. It is concluded that the antiphagocytic component comprises a critical virulence factor of the bacterium.     

Ocular toxicity of vitreal pluronic polyol F-127

To evaluate pluronic polyol F-127 (PF-127) as a vitreous substitute and an intraocular drug delivery system, a total vitrectomy was performed on 18 New Zealand rabbits (18 eyes). The vitreous was replaced with either PF-127 (9 eyes) or balanced salt solution (9 eyes). There was little difference clinically between the eyes containing PF-127 and the control eyes. Both groups showed mild postoperative inflammation, with no differences in intraocular pressures. Histopathologic findings for the control group showed no significant retinal alteration, and serial ERG findings were within normal limits. In contrast, the eyes containing PF-127 showed marked destruction of the retina by 2 weeks after surgery. The ERG amplitudes decreased dramatically to a flat tracing by 24 hours after surgery. Although it is attractive as a potential vitreous substitute, PF-127 is not safe for human use, at least at the concentration used.     

Use of saphenous vein allografts for aortopulmonary artery anastomoses in neonates with complex cyanotic congenital heart disease

Summary A saphenous vein allograft was used to create an aortopulmonary communication in 16 infants with cyanotic congenital heart disease and ductus-dependent pulmonary blood flow. These grafts measured from 3 to 8 mm in diameter and were placed between the aorta and main pulmonary artery in eight patients, between aorta and right pulmonary artery in eight, and between aorta and left pulmonary artery in one (one child had two grafts). Before heparin was used, early in the series, four of these grafts occluded and three of the four infants died during attempted revision. Another infant died early from renal failure. Late mortality has claimed four: one from cerebral hemorrhage, two from hypoxia, and one at open-heart surgery for repair. There are eight late survivors (50%).Most of the allografts were used before small diameter Gore-Tex was available; in more recent patients, 4- to 6-mm Gore-Tex grafts have been used. In our most recent patient, however, the attempt to place a Gore-Tex graft was unsuccessful, but the more pliable saphenous vein graft was readily placed and an adequate shunt obtained. Both the saphenous vein graft and the Gore-Tex have the advantage of providing pulmonary flow without the higher risk of congestive failure or pulmonary hypertension seen in patients with a Waterston or Potts anastomosis. They are easier to perform, require less anesthesia time than the Blalock-Taussig shunt, last as long as the Blalock-Taussig when done under similar conditions, and are easy to take down at the time of total repair.     

Is There a Lower Limit for Birth-weight/Gestational Age and Antenatal Steroid Therapy?

The aim of this study was to determine if there is a lower limit for birth-weight/gestational age below which antenatal steroid therapy may not improve fetal survival. The association between antenatal steroid therapy and survival to 2 years of age was assessed in 2 cohorts of children of birth-weight below 800 g or of gestational ages below 27 weeks. Antenatal steroid therapy was associated with significantly higher survival rates in infants of birth-weight 500-599 g and 700-799 g, and at gestational ages of 25 and 26 weeks. There were few survivors before 25 weeks and none below 500 g birth-weight. After adjustment for extraneous prognostic variables, antenatal steroid therapy was associated overall with approximately a doubling of the survival rates of infants of birth-weight 500-799 g, and of gestational ages 24-26 weeks. In the absence of maternal contraindications, if the goal is to deliver a surviving infant, this study suggests that the obstetrician may assist the survival chances of the tiniest and most immature infants by treating the mother with steroids before birth, with no apparent lower limit of birth-weight or gestational age.