Biochemical composition of amniotic fluid and extraembryonic coelomic fluid in the first trimester of pregnancy.

OBJECTIVE: To determine the biochemical composition of amniotic fluid and extraembryonic coelomic fluid between 8 and 12 weeks gestation. DESIGN: Prospective observational study. SUBJECTS: 40 women with a normal pregnancy between 7 and 12 weeks gestation having termination of pregnancy. INTERVENTIONS: Before termination the women had a transvaginal ultrasound guided amniocentesis. Pure samples of amniotic fluid and extraembryonic coelomic fluid were obtained from each woman and standard biochemical variables were measured in each fluid sample immediately after collection. RESULTS: Levels of sodium, potassium and bicarbonate were significantly higher in amniotic fluid whilst chloride, urea, bilirubin, protein, albumin, glucose, creatinine, calcium and phosphate were present in higher concentrations in extraembryonic coelomic fluid. All differences in concentration were significant (P less than 0.05; unpaired t-test). No relation was demonstrated between electrolyte concentrations in amniotic fluid or coelomic fluid and stage of gestation. CONCLUSIONS: Amniotic fluid and extraembryonic coelomic fluid have a widely differing biochemical composition. The biological significance of these differences remains unexplained.     

THE PSYCHOLOGICAL IMPACT OF HIP ARTHROPLASTY

The impact of total hip arthroplasty on psychological functioning was examined in 51 patients; 25 females and 26 males with a mean age of 65 years (range 42–81 years). Assessments of psychological well-being and distress were made with the Mental Health Inventory. Life satisfaction, self-rated health, and pain ratings were also obtained. Assessments were made prior to surgery, immediately after surgery, and at a 2 month follow-up. The operation produced significant improvements in psychological well-being (P < 0.001), psychological distress (P < 0.001). life satisfaction (P < 0.01), self-rated health (P < 0.001), and pain (P < 0.001). It is concluded that the changes in medical and functional status following hip arthroplasty documented in previous research are accompanied by substantial improvements in psychological state, and that the inclusion of psychological factors in hip arthroplasty research will provide a more comprehensive assessment of outcome.     

Reformulation and drop size of apraclonidine hydrochloride.

We performed a prospective, double-masked, placebo-controlled, six-period, cross-over study in which normal subjects were randomly assigned to treatment and compared three different formulations of apraclonidine hydrochloride (the present commercially available formulation, and formulations with hydroxypropylmethylcellulose or lysolecithin). We also evaluated the efficacy of a 16-microliters and 30-microliters drop size. The magnitude and duration of decrease in intraocular pressure was comparable for all formulations. Most subjects tolerated all formulations well with only a few reporting any side effects. The best-tolerated formulation was 0.5% apraclonidine hydrochloride delivered with a 16-microliters drop size. Dry mouth developed frequently with the commercially available 1% apraclonidine solution. Blurred vision complicated the use of the formulation containing hydroxypropylmethylcellulose. Both dry mouth (P less than .05) and blurred vision (P = .004) were statistically significant side effects.     

Use of long catheters for multipatient anesthetic monitoring at high respiratory frequencies

Anesthetic gases from several patients can be monitored simultaneously with a centrally located mass spectrometer. Such monitoring requires catheters from patient to spectrometer that are several meters long. Scamman (J Clin Monit 1988;4:227–229) found that when the respiratory frequency is high, as with infants, the CO₂ signal from the patient is unacceptably distorted during passage down the catheter. This is due to Taylor dispersion of the input signal. An outline of the theory of Taylor dispersion is given. The equations describe the interaction between the velocity distribution (which, in laminar flow, is parabolic) and the radial diffusion of CO₂. This interaction keeps a tracer signal together in a pulse, as it moves down the tube with themean velocity, spreading somewhat as it proceeds. How much does an initially sharp signal become blurred? The spread of such a signal when it reaches the detector, measured in time, can be expressed in various ways. Measurement is complicated, however, by the fact that the gas pressure may fall by as much as a factor of 10 along the line. The resultant expansion and acceleration of the gas cannot be ignored. A full treatment of this complication is given elsewhere, but the following simple equation is described: {ie237-1} Typically, the spread time is up to a quarter of a second for catheters of 50 m, such as used by Scamman. This is comparable with the period of CO₂ rise and fall for infants and explains the serious distortion in wave form that Scamman found. Some distortion can be eliminated by reducing R to 0.1 or less, but the extent of this improvement is small. Ideally, for fast-breathing patients, the catheter length should be reduced to 20 m or less, if possible.     

Erythropoietin levels in amniotic fluid and extraembryonic coelomic fluid in the first trimester of pregnancy.

OBJECTIVE: The aim was to measure erythropoietin levels in amniotic fluid and extraembryonic coelomic fluid from 7-12 weeks' gestation. SUBJECTS: Twenty healthy women with ultrasonographically normal first trimester pregnancies prior to surgical termination. METHODS: Paired samples of amniotic fluid and extraembryonic coelomic fluid were collected by transvaginal ultrasound guided needling. Erythropoietin was measured in both pregnancy fluids using a radioimmunoassay. RESULTS: There was a highly significant difference between erythropoietin levels in extraembryonic coelomic fluid (median level 15.45 mU/ml; range 6.8-32.1 mU/ml) and those in amniotic fluid (median 5.0 mU/ml; range < 5.0-5.8 mU/ml) (P < 0.0001; Mann-Whitney U-test). The levels of erythropoietin in maternal serum (median 15.4 mU/ml; range 5.6-29.4 mU/ml) were similar to those in the extra-embryonic coelom (P = 0.81; Mann-Whitney U-test). No relation was demonstrated between erythropoietin levels in amniotic fluid or coelomic fluid and stage of gestation. CONCLUSION: High levels of erythropoietin in coelomic fluid suggests that the hormone is involved in the process of human extraembryonic erythropoiesis. The exact regulatory role remains unknown.