Counseling and decision dilemmas associated with fetal blood sampling

Counseling before fetal blood sampling via cordocentesis is more difficult than that done before amniocentesis because 1) a fetal anomaly has been detected or is very likely, 2) the cordocentesis procedure may have a higher risk than does amniocentesis, and 3) the gestational age is frequently advanced before referral. These factors result in counseling and decision dilemmas that include that 1) the advanced gestational age may preclude the option of termination, 2) fetal prognosis may be poor despite normal cytogenetic results, and 3) the benefit of a diagnosis to provide indications for various delivery options must be weighed against the psychological burden of documenting a chromosome abnormality far in advance of delivery. Thus, counseling before cordocentesis requires engaging the couple in decision making regarding potential management of the pregnancy as a prerequisite to choosing or declining the procedure.     

Antenatal administration of betamethasone to prevent respiratory distress syndrome in preterm infants: report of a UK multicentre trial

In a prospective, randomized, double-blind, multicentre trial the effect of antenatal treatment with betamethasone phosphate was compared with placebo in the prevention of the respiratory distress syndrome (RDS) in preterm infants. The dose of betamethasone was 4 mg every 8 h for six doses, unless delivery occurred. The 251 women who were enrolled gave birth to 262 liveborn infants, 130 in the beta-methasone and 132 in the placebo group; the two groups were evenly matched in most respects. The diagnosis of RDS in the newborn was confirmed by two independent assessors. Seven of the 130 infants in the betamethasone group and 16 of the 132 in the placebo group developed RDS. In infants whose mothers had received at least three injections, RDS was also less frequent in the steroid group than in the placebo group (3/104 and 10/104 respectively; P less than 0.05). There was a significant reduction of RDS in those born between 24 h and 6 days after entry into the trial (0/30 and 8/45 respectively; P less than 0.05). The largest difference in frequency of RDS occurred in the subgroup of infants born before 34 weeks gestation, within 8 days of trial entry, and whose mothers had received at least three injections (0/27 steroid group and 7/32 placebo group; P = 0.03), and there were also significantly fewer neonatal deaths (2/27 and 13/32, respectively; P less than 0.01) in this subgroup. Betamethasone did not provoke earlier delivery. Premature rupture of the membranes and maternal hypertension did not seem to contraindicate the use of steroids: there was no increase in maternal or neonatal sepsis nor in stillbirth in hypertensive pregnancies in the steroid group. Neonatal jaundice was significantly less frequent in the steroid (55/129) than in the placebo group (81/127; P less than 0.01) but not in the subgroups born before 34 completed weeks gestation.     

Interaction of amine oxides and quaternary ammonium salts with membrane and membrane-associated processes in E. coli cells: mode of action

The antimicrobials (1-methyldodecyl)dimethylamine oxide and (1-methyldodecyl)trimethylammonium bromide affect the cytoplasmic membrane of E. coli. The interaction results in release of intracellular material (K+, 260nm-absorbing material), an effect on dehydrogenase enzyme activity and inhibition of respiration. The final effect of both substances is the same; they differ only in their dynamics. The effect of the membrane was correlated with parameters characterizing these surfactants i.e. critical micelle concentration (c.m.c.) minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) over the concentration range of 10(-4) to 10(-1) mmol/dm3 of active substance. The three stage mode of action model can be summarized as follows: 1-polar (coulombic) interactions, 2-polar and hydrophobic interactions, 3-hydrophobic interactions (extraction and solubilization). The polar and hydrophobic interactions (1st and 2nd stage) are discussed also in relation to model membranes.     

Enumeration of immunoglobulin-bearing lymphocytes in whole peripheral blood.

A new method is described for the detection by immunofluorescence of lymphocyte populations in whole peripheral blood. Lymphocytes are identified by their lack of intracellular peroxidase, and the absolute number of different populations can be accurately enumerated by avoiding procedures for isolating mononuclear cells before fluorescent staining. Among twenty-two normal individuals the mean +/- s.d. percentage and absolute number of lymphocytes with stable surface immunoglobulin were as follows: IgM, 8-1+/-2-3%, 142+/-60/mu1; IgD,8-9+/-2-2%, 212+/-85/mu1;IgA, 2-2+/-1-0%, 41+/-24/mu1; IgG, 2-3+/-1-6%, 60+/-47/mu1. It was confirmed that the detection of true IgG-bearing lymphocytes depends on washing the blood at 37degrees before staining or the use of F(ab)2 anti-IgG antibodies. The proportion of lymphocytes stained by whole IgG polyvalent anti-immunoglobulin antibody, which detects both true immunoglobulin-bearing lymphocytes (B cells) and Fc receptor cells was constant (20-5+/-1-0%) both in and between individuals, but the absolute numbers (380+/-117/mu1) varied with the lymphocyte count.