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The unsaturated fatty acid auxotroph Escherichia coli AK7 was provided with either oleic acid (cis 18:1) or linolenic acid (cis 18:3) to vary the degree of unsaturation of cell membrane lipids. The susceptibility of oleic acid- and linolenic acid-grown cells to starvation at 37 degrees C in 154 mM NaCl was compared following the decline in the number of CFU by plating the cells on agar medium. The decline in CFU was faster for linolenic acid-than for oleic acid-grown cells, but it was not indicative of cell death, since culturable CFU was recovered after respirable substrate was added to the starved cell suspension. Cell envelope microviscosity (determined by fluorescence polarization) of oleic acid- and linolenic acid-grown cells was equal in the presence of a respirable substrate, but in its absence the microviscosity of linolenic acid-grown cells was lower than that of oleic acid-grown cells. The results suggest that cell envelope microviscosity is an important factor in determining the sensitivity of E. coli to conditions of nutrient depletion.

The cord blood from 82 normal newborns (48 males and 34 females) has been extensively investigated, to check p50, cooperativity and related parameters. The most important results are the following: Neonatal p50 is slightly above 20 torr, in good agreement with the literature data, but this value refers to the p50 "CO-free" (T50); otherwise, the original p50 is slightly less than 22 torr, a value which is not indicative enough, because neonatal blood contains a consistent excess of Hb-CO. Either this CO-excess and the low p50 value seem to be mainly depending on the low binding capacity of Hb-F with DPG, even if further studies are still necessary at regard. The empirical factor correcting adult p50 to T50 is -0.27, a value which must be increased to -0.36 for neonatal blood. Multiple gas analyses of the samples indicate that oxygen transport is a very complicate equilibrium involving pH, CO2, bicarbonate balance and other factors. A complete statistical analysis of the data has been carried out and the main result indicates that oxygen assumption favours CO2 releasing and vice versa, a phenomenon already well known and globally called "Bohr effect".

Reopening of ventricular septal defect after surgical repair was investigated -- from six months to five years after operation -- on 75 patients who had undergone closure of ventricular septal defect and on 65 patients who had undergone complete correction of tetralogy of Fallot. The complication appeared in 3 patients (4%) of the first group and in 4 (6%) of the second group, always early after the operation (from 24 hours to 2 months). All patients underwent reoperation - operative mortality rate was 66% in the first group and 25% in the second one. Operative mortality was higher in patients with cardiac and/or tricuspidal failure, also after prolonged preoperative medical treatment.

The Escherichia coli membrane-bound D-lactate dehydrogenase and succinate dehydrogenase were assayed on the basis of the phenazine methosulfate- (PMS-) mediated reduction of the tetrazolium salt, MTT. An initial slower phase (lag) in the time-course of the reaction was observed and analyzed. The results were as follows. (1) The time lag in the assay of the D-lactate dehydrogenase was eliminated by preincubating the membranes with PMS plus D-lactate, with PMS plus succinate, or with PMS plus NADH (conditions which implicated PMS reduction). (2) When the D-lactate dehydrogenase was assayed by another method based on the measurement of the pyruvate formed, neither was a time lag observed nor was the enzyme activity affected by membrane preincubation with PMS plus D-lactate. (3) Although the superoxide radical was involved in MTT reduction, this radical seemed not to participate in the generation of the time lag. (4) Membranes whose D-lactate dehydrogenase activity had previously been destroyed by heating at 80 degrees C for 1 min, were able to prolong the time lag in MTT reduction when added to the assay medium for the D-lactate dehydrogenase from untreated membranes, whereas membranes previously heated at 100 degrees C instead of 80 degrees C did not have this effect. It was concluded that the E. coli membranes interfered in the dehydrogenase assay based on the PMS-mediated reduction of MTT. The time lag was interpreted as a period during which the interfering substance reacted with reduced PMS inhibiting the reduction of MTT.

Twenty patients between 14 and 28 gestational weeks were scanned on three occasions during a single day by six operators with different ultrasonic experience (three use a compound scanner and three a real-time equipment). On each occasion every operator had to measure in a "blind" manner the fetal biparietal diameter (BPD), head circumference and abdominal circumference (HC and AC); a coded copy of head and abdominal circumference was subsequently measured by one of the members of the staff. Statistical analysis was carried out on the 1800 measurements, and it was concluded that the accuracy was not dissimilar from that reported by pilot studies. The reproducibility of the parameters studied did not change throughout pregnancy and real-time and compound scanner yielded homogeneous results.

Fecal fat excretion was studied after a mild episode of diarrhea in eight infants for whom adequate control data were available. Mean age of onset of diarrhea was 28 days. Duration of the episode, defined as the number of days until the infant was again feeding and libitum, averaged 5.1 days. Balance studies were carried out 3 to 13 days later. Mean fecal fat excretion rose from a prediarrhea value of 2.9 +/- 1.4 gm/day to 8.7 +/- 3.1 gm/day following diarrhea (P less than 0.001). Restudy of five infants one month later showed persistent steatorrhea in one. Mild transient steatorrhea may follow mild diarrhea in infancy and should be considered in infants who are slow to gain weight subsequent to an episode of diarrhea.