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OBJECTIVE: Cord blood pH, lactate, hypoxanthine, and erythropoietin levels has all been used as markers of either acute or chronic asphyxia. We sought to determine whether these index values were significantly different in infants with or without meconium-stained amniotic fluid. STUDY DESIGN: Fifty-six pregnant women in spontaneous labor at term were divided into two groups on the basis of the presence or absence of meconium-stained amniotic fluid. All meconium-stained fluid was centrifuged, and the volume percentage of particulate mater (i.e., meconium) was recorded. Umbilical artery blood and mixed arterial and venous cord blood were obtained at each delivery. Lactate, hypoxanthine, and erythropoietin levels were measured. Statistical analysis included Student t test and rank sum statistics where appropriate. Normal and Spearman correlation coefficients wer also used. RESULTS: There were no significant differences in mean umbilical artery pH 97.26 ± 0.06 vs 7.25 ± 0.10), lactate levels (32.8 ± 10 mg/dl vs 30.4 ± 14.2 mg/dl), and hypoxanthine levels (13.4 ± 6.7 μmol/L vs 14.0 ± 6.0 μmol/L) in newborns with meconium ( n = 28) compared with controls ( n = 26). Erythropoietin levels were significantly greater in newborns with meconium (median 39.5 mlU/ml vs 26.8 mlU/ml, p = 0.039). There was no correlation between the amount of particulate matter and any marker of asphyxia. CONCLUSIONS: There was no correlation between markers of acute asphyxia (i.e., umbilical artery blood pH, lactate, or hypoxanthine) and meconium. However, erythropoietin levels were significantly elevated in newborns with meconium-stained amniotic fluid. This latter marker may better correlate with chronic asphyxia.

OBJECTIVE: The purpose of this study was to determine the stability of oxytocin in lactated Ringer's solution and lactated Ringer's–dextrose 5% solution over a 24-hour period at 25°C and over a 7-day period at 5°C. STUDY DESIGN: Twenty units (2.1 μg equal 1 unit) of oxytocin were injected into 1000 mL of lactated Ringer's solution and lactated Ringer's–dextrose 5% solution. Samples for the analysis were drawn at specified times after storage at 5°C and 25°C. These samples were stored at −70°C for later analysis. Statistical analysis was done with 1-way analysis of variance and Tukey-Kramer multiple comparisons. RESULTS: Twenty units of oxytocin in 1000 mL of lactated Ringer's solution and lactated Ringer's–dextrose 5% solution was found to be stable for 7 days at 5°C and for 24 hours at 25°C. CONCLUSION: Premixed oxytocin solutions in lactated Ringer's solution and lactated Ringer's–dextrose 5% solution are stable in conditions commonly found in dispensing pharmacies and labor and delivery units. This finding could lead to the more efficient use of personnel during the mixing process, could provide solutions that are aseptically prepared, and could be a tool to reduce costs and improve patient care. (Am J Obstet Gynecol 2002;186:496-8.)

OBJECTIVES: In vitro perfusion of human placentas was used to quantify the net placental transfer of ticarcillin and clavulanic acid. STUDY DESIGN: Placentas were obtained from uncomplicated pregnancies at term. The maternal and fetal circulations were reestablished at flow rates of 17.5 ml/min and 5 ml/min, respectively. Open circulations were used to evaluate steady-state pharmacodynamics and transplacental gradient formation. Drug levels were measured by high-pressure liquid chromatography. RESULTS: The clearance index of ticarcillin was 0.037 ± 0.004. The fetal/maternal ratio was 0.91. Therapeutic concentrations of clavulanate (2 to 6 11g/ml) in the maternal media resulted in undetectable transfer to the fetal compartment. By using higher levels of clavulanate, a clearance index of 0.061 ± 0.001 (mean ± SEM) and 1 : 1 fetal/maternal gradient was obtained. CONCLUSIONS: These data correspond to relatively low transfer of ticarcillin with a cord/maternal ratio of \lt 1. Clavulanate transfer is slightly greater. Agents with similar acitvity and superior transfer would optimize intrauterine treatment. (AM J OBSTET GYNECOL 1992;167:1595-9.)

OBJECTIVE: The purpose of this study was to compare the maternal-fetal placental transfer of 2',3'-dideoxyinosine and 2',3'-dideoxycytidine with that of 3'-azido-2', 3-dideoxythymidine (azidothymidine). STUDY DESIGN: The perfusion system used carbon 14-labeled antipyrine as a reference compound to determine the clearance index of each compound. The inhibitor dipyridamole and the endogenous bases were used to determine if these anti-human immunodeficiency virus compounds crossed the placenta other than by simple diffusion. RESULTS: The clearance index of azidothymidine was 0.29 ± 0.04 at maternal concentrations of 1.0 to 10 µg/ml, and the clearance index of 2' ,3'-dideoxyinosine was 0.14 ± 0.05, which was 48% of the clearance index of azidothymidine. The clearance index of 2',3'-dideoxyinosine was essentially identical to azidothymidine in the range from 1 to 10 µg/ml. The results of the closed-closed studies suggest that at therapeutic peak concentrations of 1 to 2 µg/ml of these compounds in the maternal circulation therapeutic levels will be reached in the fetal circulation. CONCLUSION: These anti-human immunodeficiency virus inhibitors appear to cross the placenta rapidly by simple diffusion because (1) the transfer of the drugs to the fetal circulation was not saturable even at 100 µg/ml, (2) there was no change in clearance index with the addition of 300 µmol/L of thymidine, inosine, cytosine, or 30 µmol/L dipyridamole, and (3) there was no accumulation against the maternal fetal or fetal maternal concentration gradient. (AM J OBSTET GYNECOL 1992;167:1570-4.)

To assess placental metabolism of cocaine, placentas were obtained at the time of delivery and the microsomes were extracted by ultracentrifligation within 2 hours. Placental microsomes were cultured with cocaine at physiologic plasma concentrations similar to those of cocaine users (0.75 µg/ml). Two control groups were established. In the first group an anticholinesterase was added to the culture to suppress enzyme activity, and in the second cocaine was cultured alone without placental microsomes to obtain baseline spontaneous conversion of the drug. The results indicate that cocaine is biotransformed by the human placenta, presumably by cholinesterase activity. This suggests that the placenta may provide a moderate degree of protection from cocaine-induced morbidity, such as abruptio placentae and fetal growth retardation, by converting cocaine into less active metabolites. These results also have pharmacogenetic implications because cholinesterase activity varies among individuals. Hence placentas that cannot transform the drug may place the conceptus at greater risk of developmental abnormalities.

By using a high-pressure liquid chromatography assay, we investigated the ability of collagen shield therapeutic contact lenses to release amphotericin B and deliver it to the anterior segment of rabbit eyes. In vitro studies showed that presoaked collagen shields released most of the amphotericin B within the first hour of elution. We compared the corneal and aqueous humor amphotericin B levels produced by collagen shields soaked in amphotericin B and frequent-drop therapy at four time points over a six-hour period. The collagen shields soaked in amphotericin B produced corneal levels that were higher than those produced by frequent-drop therapy at one hour, equivalent to drop therapy at two and three hours, and lower than drop therapy at six hours. There were no differences in amphotericin B levels in aqueous humor at any time point between rabbits treated with collagen shield delivery and rabbits treated with frequent-drop delivery. The results of this study suggest that amphotericin B delivery to the cornea by collagen shields is comparable to frequent-drop delivery but has the potential benefit of added convenience and compliance.

Moxalactam is a newer beta-lactam antibiotic with increased activity and an extended antimicrobial spectrum. Three 1 gm doses were given to women scheduled for elective vaginal hysterectomy. This perioperative regimen was prospectively compared to identical doses of cefazolin, a first-generation cephalosporin of proved efficacy. The overall incidence of major postoperative infection in 193 women was less than 5% and there were no significant interregimen differences. The incidence of major infection was directly related to the type of procedure performed.

A total of 1140 aerobic and anaerobic isolates were recovered from cultures of specimens from the reproductive tracts of 435 uninfected patients who underwent elective hysterectomy. Standard minimum inhibitory concentration susceptibility studies were performed on these isolates to 13 newer penicillins, cephalosporins, and some traditional antimicrobial agents. These data were generated to evaluate the in vitro efficacy of these antibiotics for potential use in prophylaxis or as a single agent for treatment of polymicrobial infections of the female pelvis. The minimum inhibitory concentration data for each antibiotic against 16 genera of aerobic and nine genera of anaerobic bacteria were determined and were used to compare the in vitro antimicrobial activity of newer antibiotics to that of the more traditional antibiotics. Of the antimicrobial agents tested, piperacillin had the highest in vitro activity against these isolates of any antibiotic tested.

Twenty-one women who underwent radical abdominal hysterectomy and pelvic lymphadenectomy were enrolled in a prospective, comparative, randomized, placebo-controlled clinical trial of antimicrobial prophylaxis. Preoperative endocervical flora was identified and was similar in pre- and postmenopausal private and clinic service women; 46% of the 119 preoperative isolates produced beta-lactamase enzyme. Women were given three doses of either placebo or cefoperazone plus sulbactam, an irreversible beta-lactamase enzyme inhibitor. Three women (27%) given placebo developed abdominal incision infections; one women given placebo also developed a pelvic infection. None given antibiotic developed operative site infection, but one women developed a drain site infection. A major operative site infection rate of 27% observed with placebo is high enough to warrant prophylaxis. Although antimicrobial prophylaxis at radical hysterectomy and pelvic lymphadenectomy eradicted operative site infection in our patient populations, a literature review indicates that individual determination of a requirement for prophylaxis is necessary.

The practice of administering perioperative antimicrobials to uninfected patients undergoing elective surgical procedures has been subjected to careful prospective investigative scrutiny during the past two decades. A wound classification system was developed, helping to identify procedures for which prophylaxis did not provide benefit to the patient. Guidelines for prophylaxis in hysterectomy were proposed and risk factors were sought. Pharmacokinetics and spectrum of antibacterial activity, although variables of paramount importance in predicting success in the treatment of established infections, were discovered to have questionable impact on prophylactic efficacy. Duration of antimicrobial administration has gradually diminished from the total length of hospital stay to a single preoperative dose without increased risk of infection; efficacy may be related to route of administration. The wisdom of using newer agents for prophylaxis is addressed and questioned.

The metabolism of cefotaxime (CTX) by hemolyzed blood at different concentrations, time intervals, and temperatures was studied. Cefotaxime and desacetylcefotaxime (DES) levels were quantitated by reverse phase high pressure liquid chromatography. When CTX was added to tubes with 10% hemolysis, CTX/DES levels (micrograms per milliliter) were 123/134, 161/114, and 202/60 at 37°C, room temperature, and 4°C, respectively, after a 1 hr incubation. No reduction in CTX was observed in control experiments (10% blood, no hemolysis) at these temperatures after 1 hr; 200 ± 23 μg/ml CTX; 5 ± 2 μg/ml DES. The disappearance half-life of CTX in 10% hemolyzed blood at 37°C was 45.7 min and at room temperature 84.3 min ( p p -hydroxymercuibenzoate reduced the metabolism of CTX in the presence of 10% hemolysis after 1 hr at 37°C from 41% to 19% with ethylenediaminetetraacetic acid (0.45 mM) and to 0% with p -hydroxymercuibenzoate (10 mM). Our results suggest that for accurate determinations of CTX serum levels, which often have some degree of hemolysis, such specimens should be collected in tubes with ethylenediaminetetraacetic acid or p -hydroxymercuibenzoate and transported at 4°C.

Antimicrobial overutilization accelerates the development of bacterial resistance. A prospective, randomized, blinded clinical trial of vaginal hysterectomy prophylaxis was designed to compare the efficacy, safety, and costs of cefazolin with those of cefoxitin and cefotaxime. Sixteen women (7.5%) developed febrile morbidity only, 10 (4.7%) developed major pelvic infection requiring parenteral antimicrobial therapy, and neither clinical nor laboratory adverse reactions of significance were observed. Anemia, diabetes, and additional surgical procedures were associated with a significantly increased incidence of postoperative infection; no regimen was more protective for women with or without these risk factors. Infections almost doubled hospital stay and the charges for health care. Diagnosis-related group reimbursement would have been more than $1,300 less than the mean hospital charge for women who developed infection. Utilizing cefazolin for prophylaxis and reserving cefoxitin and cefotaxime for therapy is cost and antimicrobial efficient.

Pentamidine is used to treat Pneumocystis carinii pneumonia. The incidence of this infection in pregnancy has paralleled the increasing incidence of acquired immunodeficiency syndrome in pregnancy. Using the in vitro bidirectionally perfused human placenta, we studied the transfer of pentamidine across the placenta. Pentamidine was added to the maternal circulation at therapeutic concentrations (2 wg/ml). No transfer of pentamidine was detectable with a newly devised high-performance liquid chromatography method sensitive to 0.05 wg/ml of pentamidine. Increasing the pentamidine concentration tenfold produced a low level of transfer to the fetal circuit. Fetal concentrations were far below maternal perfusate concentrations. Placental tissue levels were higher than media levels. These data are suggestive of minimal drug transfer to the fetus and significant concentration of the drug in placental tissue. (Am J Obstet Gynecol 1989;160:759-61.)

worm-like segmented forms with an internal tubular structure-“adults,” and numerous intermediate forms-“larvae.” All of these structures stained distinctly and demonstrated reddish purple granules. Many of the elongated forms appeared to us to be of vegetable origin, and their internal structure showed blue and red birefringence under polarized light. All of the smears containing cotton wool clippings showed vast numbers of “worms,” and those from gauze-filtered serum showed abundant spheres and intermediate forms. These inclusions were indistinguishable microscopically from those seen in blood films made directly from patient’s blood. We concluded that “Hydatoxi luulba” is a common laboratory contaminant, cellulose fibers, especially cotton wool. The worm-like appearance of cotton fibers when sulfated and stained with toluidine blue-0 can be explained by their molecular structure. Cotton fibers are composed of almost pure strands of cellulose fibrils which in turn are composed of chains of n-glucose units, each of which contains three free hydroxl groups.’ When cotton fibers are exposed to the sulfuric acid-ether sulfation reagent, the hydroxyl groups are esterified and react with toluidine blue-0 to assume a reddish purple appearance.3 The inner structures of the artifacts are the visible cellulose macrofibrils of the cotton fibers, and the outer segmented portion is an envelope of cellulose microfibrils attached in a bottlebrush fashion to the macrofibrils. The microfibrils are about 10 nm wide and thus are invisible by light microscopy unless stained.’ The spheres, or “eggs,” are small particles of cellulose and globules of microfibrils which have sloughed off from the main cotton fiber. We believe that the objects described by Lueck et al. are artifacts created bv cotton or other cellulose fibers and are unrelated to disease. The sources of fibers are legion-laboratory coats, clothing, bandages, alcohol swabs-and are ubiquitous in a hospital environment. Careful examination of a scrupulously cleaned microscope slide will show contamination by dust particles from atmospheric sources.