A comparison of reward processing during Becker-DeGroot-Marschak and Vickrey auctions: An ERP study.

Vickrey auctions (VA) and Becker-DeGroot-Marschak auctions (BDM) are strategically equivalent demand-revealing mechanisms, differentiated only by a human opponent in the VA, and a random-number-generator opponent in the BDM. Game parameters are such that players are incentivized to reveal their private subjective values (SV) and behavior should be identical in both tasks. However, this has been repeatedly shown not to be the case. In this study, the neural correlates of outcome feedback processing during VA and BDM were directly compared using electroencephalography. Twenty-eight healthy participants bid for household products which were then divided into high- and low-SV categories. The VA included a human opponent deception to induce a social environment, while in reality a random-number-generator was used in both tasks. A P3 component peaking at 336 ms over midline parietal sites showed more positive amplitudes for high bid values, and for win outcomes in the VA but not the BDM. Both auctions also elicited a Reward Positivity potential, maximal at 275 ms along the central midline electrodes, that was not modulated by auction task or SV. Further, an exploratory N170 potential in the right occipitotemporal electrodes and a vertex positive potential component were stronger in the VA relative to the BDM. Results point to an enhanced cortical response to bid outcomes during VA task in a potential component associated with emotional control, and to the occurrence of face-sensitive potentials in VA but not in BDM auction. These findings suggest modulation of bid outcome processing by the social-competitive aspect of auction tasks. Directly comparing two prominent auction paradigms affords the opportunity to isolate the impact of social environment on competitive, risky decision-making. Findings suggest that feedback processing as early as 176 ms is facilitated by the presence of a human competitor, and later processing is modulated by social context and subjective value.

Correlations of mechanical stability, morphology, pulmonary surfactant, and phospholipid content in the developing lamb lung.

Pressure-volume characteristics and surface tension measurements of the lamb of 120 to 130 days gestational age were typical of the mature lung in the upper lobes and the immature lung in the lower lobes. By term both upper and lower lobes had findings characteristic of the mature animal. Phospholipid concentration per milligram DNA and per cent saturated fatty acids on pulmonary phosphatidyl choline were relatively constant from 60 to 120 days gestational age; thereafter there was a significant increase in both measurements. These changes usually coincided with an increase in osmiophilic inclusion bodies in the large alveolar cell.A concentration of disaturated phosphatidyl choline per milligram DNA in excess of 0.170 mg per mg was associated with a minimal surface tension below 13 dynes per cm (p < 0.001). Newborn animal lungs contained over 3 times this critical concentration, whereas adult lungs contained 1.5 times this value. The excess disaturated phosphatidyl choline per milligram DNA may represent a reservoir of pulmonary surfactant.

Transcutaneous determination of arterial oxygen tension.

Arterial oxygen tension measurements were performed simultaneously using two different techniques: (1) the conventional method of analyzing a blood sample obtained from the radial artery by means of a Clark electrode and (2) a new method of transcutaneous oxygen tension recording using a newly developed surface electrode containing a built-in heating device to ensure optimal cutaneous perfusion at the site of measurement. Two groups of newborn infants were used as subjects: (1) 70 clinically healthy babies who were tested during normoxia and hyperoxia (breathing 80% to 100% oxygen) and (2) 20 sick preterm and term infants receiving inspired oxygen concentrations of between 21% and 100% during the measurement. Our results indicate a satisfactory accuracy for the transcutaneous oxygen tension measurements in normoxia and hyperoxia (percentage coefficient of variation, 15.9% and 24.1%, respectively). In hypoxia agreement between the two methods varies depending on the degree of circulatory derangement. Overall correlation coefficients were greater than 0.85 in each group.

Interferences in the radioimmunological determination of urinary free cortisol.

The magnitude of interferences arising in the radioimmunological assessment of urinary free cortisol is studied (a) by comparing cortisol immunoreactivities from crude urine, after organic solvent extraction of different selectivity and after additional chromatography by high pressure liquid chromatography (HPLC) and (b) by evaluation of the profile of immunoreactivity resulting from the fractions eluted by HPLC. Three antisera from different sources have been investigated. Values of cortisol-immunoreactivity in crude urine were about six times and values of a simple dichloromethane extract about three times higher than values obtained after HPLC. The main part of the interfering compounds arising in organic extracts have a polarity similar to cortisol, which cannot be easily eliminated by simple solvent extraction procedures. Specific estimation of urinary cortisol by radioimmunoassay requires a preceding chromatographic technique of high efficiency, such as HPLC, which represents an adequate tool for the routine laboratory.

Specific and practicable assessment of urinary free cortisol by combination of automatic high-pressure liquid chromatography and radioimmunoassay.

An assay for the specific measurement of urinary free cortisol excretion is described. The method involves a simple solid-phase extraction, automatic high pressure liquid chromatography (HPLC) and radioimmunological quantification. The concurrent study on antigenically interfering compounds in the organic extract of urine revealed that non-specific immunoreactivities with a chromatographic behaviour very similar to cortisol are present in urine, which are not attributable to the steroids commonly studied for cross-reactivity. Non-chromatographed values are about twice as high as those chromatographed by HPLC. Correlation between them was significant (r = 0.98). Precision and accuracy of the present method are within the range commonly achieved by radioimmunoassay methods. The normal range of urinary free cortisol excretion was found to be 28--117 nmol/24 h (n = 128). The present method, suitable for routine purposes, provides a basis for external quality control of urinary cortisol estimations, which is inadequate with the non-specific methods usually applied.

[Perforation of the small intestine in patients with hernia]. / Dünndarmperforation bei Hernienträgern.

Two cases of intestinal perforation associated with inguinal hernia or incisional hernia are presented along with a review of the literature. The great majority are men over the age of 45 with a reducible and usually right-sided inguinal hernia. When a loop of bowel lies opposite a point of weakness in the abdominal wall, such as a hernial orifice, and intraabdominal pressure suddenly rises, the resulting intraluminal pressure ruptures the bowel where it is unsupported. Perforation results in diffuse peritonitis in a few hours. The treatment consists in laparotomy, simple closure of the perforation and drainage of the abdomen. Repair of the hernia is recommended 2 months after healing of the peritonitis. If the complication is early detected and treated the outcome is good.

Oxygen monitoring in neonatal medicine.

In perinatal intensive care medicine, hypoxia and hyperoxia are both detrimental to the patient. PO2 measurements of arterial blood can be done in different ways: (1) by analysing blood obtained from an arteriopuncture; (2) by analysing blood obtained from an indwelling arterial (usually umbilical) catheter; (3) by using an indwelling catheter with a built-in O2 electrode; (4) by analysing alveolar air for PO2; (5) by measuring cutaneous arterial PO2 transcutaneously. The common principle of all electrodes mentioned is the polarographic one. It appears that for the clinician, the transcutaneous electrode will become the method of choice in the future because of its non-invasiveness to the patient and because of its capability to provide a continuous PO2 record.

CO2 breathing of children.

In 20 co-operative paediatric patients without cardiopulmonary disease, 2 and 4% CO2 in air were given to breathe and the ventilatory response as well as end-tidal CO2 were recorded. A rise of ventilation concomitant with a rise in alveolar CO2 was seen in most cases. The amount of ventilatory response was less than that previously reported with tube rebreathing for any given rise in alveolar PCO2. It appears therefore, that in addition to the absolute level of PaCO2, the mode of presentation of the CO2 signal to chemosensitive areas also serves as an important determinant for the amount of the ventilatory response.

[One year of basic examination of neonates (author's transl)]. / Ein Jahr Neugeborenen-Basis-Untersuchung

During the basic examination (U-2) between the 5th and 10th days of life, 104 pathological findings were made in 93 out of 538 children born in a general practitioner hospital. The incidence of 25% pathological findings in neonates, of which about 70% were obtained at the U-2, in our opinion, justifies the U-2 as a routine measure for all neonates. The percentage of positive findings in neonates from unselected pregnancies must be estimated still higher.

A convenient and efficient method for the extraction and fractionation of steroid hormones from serum or urine.

A convenient solid phase method for extracting and fractionating steroid hormones from serum or urine is presented. The influence of the solvent used for extraction, of the body fluid to be extracted, and of the degree of sample dilution on the efficiency of extraction was studied for progesterone and cortisol. The potency of fractionation was demonstrated by the separation of the steroid pairs, deoxycortisol--cortisol and oestradiol--oestriol, from a urine sample. Influence of ionic strength, pH and temperature on the reproducibility was assessed for deoxycortisol in undiluted urine. With respect to practicability and efficiency, this method has proved to be considerably superior to conventional liquid-liquid techniques.

Metabolic rate and O2 consumption in newborns during different states of vigilance.

In 135 asymptomatic newborn infants, 1--53 days of age, body weight 1,820--4,120 g, indirect calometry was performed. According to the state of wakefulness the infants showed during the testing procedure, they were divided into four groups of vigilance (V1--V4). Metabolic rate and oxygen consumption showed similar results between groups V1, V2 and V3 (deep sleep; REM sleep; wakefulness with no muscular activity). V4 infants (with muscular activity) had a higher metabolic rate and O2 consumption. Correlation between metabolic rate and body surface area is similar in V2 and V3 but shows a steeper slope in the V1 group. It is speculated that central regulatory mechanisms may account for this difference.

Suppressive effect of metyrapone on plasma corticotrophin immunoreactivity in normal man.

Short term alterations of plasma corticotrophin immunoreactivity (ACTH) and cortisol were studied in healthy men under basal conditions and during intravenous administration of metyrapone. In the intravenous experiment, a low dose (1 g/5 h) and a high dose (4 g/5 h) of metyrapone ditartrate were infused. In the early phase of the metyrapone experiments, plasma ACTH fell from 9.46 +/- 0.95 (SE) pmol/l at 08.00 h to 7.7 +/- 1.1 pmol/l at 09.00 h (P greater than 0.05) in the low-dose experiment, and from 7.0 +/- 1.6 pmol/l to 4.6 +/- 0.9 pmol/l (P less than 0.05) in the high-dose experiment. A significant delayed increase of plasma ACTH secondary to the hypocortisolaemic stimulus was apparent in the high-dose experiment, in which plasma cortisol was maximally suppressed to 14 +/- 3 nmol/l at 13.00 h. No significant increase was observed in the low-dose experiment, the maximal suppression of plasma cortisol being 46 +/- 9 nmol/l at 14.00 h. The present data suggest dual effects of metyrapone on plasma ACTH: 1) a suppressive effect, the mechanism of which is not yet understood, and 2) the known increasing effect of 'feed-back' stimulation, which seems to be very sensitive to alterations of plasma cortisol only at cortisol levels lower than about 50 nmol/l. The suppressive effect of metyrapone may account for the frequently described inadequate response of plasma ACTH to metyrapone-induced hypocortisolaemia. Particularly, the diagnostic validity of the very short versions of the metyrapone test would seem to be seriously questioned.

Should blood glucose monitoring be done in overweight and/or giant infants of non-diabetic mothers?

Monitoring of serum glucose levels in 60 asymptomatic overweight (4.000-4.499 g) and giant (greater than 4.500 g) newborns of non-diabetic mothers during the first 72 hours of life did not reveal pathological values. The mean result of giant infants was lower than that of the group less than 4.500 g. In mothers of overweight infants diabetes mellitus should always be kept in mind. However, the diagnosis may be difficult particularly in its latent form due to metabolic alterations caused by pregnancy. For this reason it is necessary to monitor blood glucose levels for hypoglycemia in these newborns just as in infants of mothers having a manifest diabetes mellitus.

Heterogeneity of corticotropin-immunoreactive compounds in human body fluids.

Using reversed-phase "high-performance" liquid chromatography and hydrophilic ion-pairing reagents, we studied the chromatographic profiles of corticotropin immunoreactivities in human plasma, cerebrospinal fluid, and urine. The chromatographic system we applied provides excellent separation of peptide molecules, with reproducibility (CV) of retention times better than 0.5%, and makes feasible the subsequent immunological quantitation of eluted fractions. Profiles of corticotropin immunoreactivities exhibited several chemically different compounds in each of the three body fluids studied. A considerable portion of these immunoreactive compounds is more hydrophilic and probably of lower molecular mass than the human corticotropin 1-39 molecule itself. These hydrophilic molecules are more predominant in urine and plasma than in cerebrospinal fluid.

Intrauterine growth of twins. A retrospective analysis.

In a retrospective study of 150 twins born between 1970-1977, birth weight, length, and head circumference was plotted against gestational age. In comparison to singletons, all 3 parameters were low normal. While length and head circumference values follow the growth pattern of singletons, prenatal birth weight shows a progressive decline toward maturity. The intrauterine growth pattern of twins resembles that of intrauterine growth retardation of singletons.

Adaptation to extrauterine existence: cardiac and respiratory rates during the first 72 hours.

In 29 asymptomatic underweight newborns, 10 true preterms and 19 small-forgestational age (SGA), recordings of respiratory and cardiac rates were performed during the first 72 hours of life. The results may be summarized as follows: 1. Respiratory rates (RR) are slightly elevated during the first day of life. 2. The respiratory-to-cardiac ratio (RR/CR) is very constant throughout the first three days. 3. Low-Apgar infants initially have an elevated RR. 4. True preterm infants have higher cardiac rates (CR) than SGA infants. Not all of the phenomena observed can be totally explained on the basis of existing knowledge.