Validation of the 1988 ACOG forceps classification system

In February 1988, an ACOG Committee Opinion substantially revised the classification of forceps operations. The revision addressed two significant shortcomings of the old system: Outlet forceps had been defined too narrowly and midforceps too imprecisely. We now report the results of a prospective study of 357 forceps deliveries classified using each system. Allowing up to 45 degrees of rotation in an outlet forceps delivery did not increase morbidity measured by any criterion. Dividing the old midforceps group by precisely identifying station and rotation permitted greater stratification of the risks of short-term neonatal and maternal morbidity. We conclude that our results validate the 1988 classification scheme.     

Ocular Inflammatory Pseudotumor Associated with Propranolol Therapy

A 60-year-old man presented with a unilateral mass involving the iris and ciliary body associated with iridocyclitis, which was refractive to both topical and systemic corticosteroid therapy. After a systemic work-up was negative, anterior chamber paracentesis and transcorneal biopsy were performed to rule out malignant melanoma and other tumors. The lesion proved to be an inflammatory lymphoid process, which resolved when systemic propranolol administration was withdrawn. Evidence for the possible role of propranolol in the induction of an intraocular inflammatory pseudotumor is presented.     

Behaviorally measured refractory periods are lengthened by reducing electrode tip exposure or raising current

Small tip exposures and high currents allow the stimulation of high-threshold axons. These studies were conducted to measure the effects of current and tip surface area on stimulation parameters required to produce a constant rate of self-stimulation of lateral hypothalamic sites, or of circling when stimulating medial brain stem sites. Thresholds for circling decreased when tip surface area was decreased to 0.01 mm2. Refractory period curves for both circling and self-stimulation were shifted to slightly longer intrapair intervals when tip surface area was decreased or current was increased. This suggests that long refractory period axons make larger contributions when current density is increased. Chronaxies were not lengthened by small tip exposures but were reduced when electrodes were placed far lateral to the circling substrate.     

Effect of Cigarette Smoking on Duodenogastric Reflux of Bile Acids*

Abstract: The possibility that smoking induces duodenogastric reflux was examined in 13 healthy male volunteers. Gastric juice was aspirated for four consecutive 20-minute periods, and reflux quantitated by measuring total bile acids (TBA), chenodeoxycholic acid (CDCA) and glycocholic acid (GCA) in the juice. One cigarette was smoked during either period 2 or period 3. Amounts of bile acids (μmoles; means ±SEM) refluxing into stomach during the pre-smoking, smoking, and post-smoking periods respectively were: TBA—4.5 ± 1.1, 5.4 ± 3.0 and 3.9 ± 1.6; CDCA— 1.7 ± 0.6, 1.5 ± 0.9 and 2.0 ±1.1; GCA—1.8 ± 1.7, 1.1±0.6 and 1.0 ± 0.6. Paired analysis revealed no significant effect of smoking on any of these parameters. These findings, based on quantitative methods, do not confirm those of previous unblinded and semiquanti-tative studies. We conclude that smoking one cigarette does not provoke duodenogastric reflux.     

Blockade of the complement C5a receptor reduces incisional allodynia, edema, and cytokine expression

BACKGROUND: Activation of the complement system is one component of the inflammatory response. Various components of the complement system participate in killing foreign organisms, recruiting immune cells, enhancing edema, and stimulating cytokine formation. Complement-mediated enhancement of the inflammation surrounding surgical incisions may increase pain. METHODS: In these studies, the authors used a murine hind paw incisional model to study the role of the complement C5a receptor in supporting incisional inflammation. At baseline and at various time points after incision, they measured the effects of a highly selective C5a receptor antagonist on nociceptive thresholds, edema formation, and cytokine production in the skin surrounding the incision. They also measured changes in C5a receptor expression near the incisions. RESULTS: The once-daily injection of the C5a receptor antagonist AcF-[OPdChaWR] reduced mechanical allodynia and edema in the incised hind paw. A multiplexed cytokine assay revealed that 8 of the 18 cytokines examined showed significant increases in skin tissue abundance after incision. Distinct time courses for the patterns of elevation were seen, though some degree of resolution occurred for all cytokines within 96 h. For 7 of these 8 cytokines, the C5a receptor antagonist reduced the enhancement of expression. In addition, the authors found that the C5a receptor messenger RNA level increased 15-fold in the skin surrounding the incisions within 24 h and then slowly declined. CONCLUSIONS: The tissue directly surrounding incisions in mouse hind paws undergoes large changes in the content of specific cytokines in addition to demonstrating edema and nociceptive sensitization. By blocking the receptor for one component of the complement system, C5a, all of these changes can be reduced. Complement receptor inhibitors may constitute a novel group of compounds useful in reducing the pain and swelling of surgical incisions.