An improved gas chromatographic method for measuring glucosamine and muramic acid concentrations

A method of simultaneously measuring glucosamine and muramic acid concentrations in marsh grass litter was developed. Spartina alterniflora samples were preextracted with acetone to remove lipids containing amino sugars and then hydrolyzed in 6 N HCl (100 degrees C, 4.5 h). Amino sugars in the hydrolysates were isolated by ion-exchange chromatography, which gave good recoveries (greater than 90%) and reproducibility (CV less than 5%). Isolated amino sugars were converted to O-methyloxime acetates. beta-Phenylglucose and N-methylglucamine were added as internal standards. Sample derivatives were quantified by capillary column gas chromatography. OV-101 and SE-54 capillary columns completely separated glucosamine and muramic acid from other amino sugars. The detection limit of glucosamine and muramic acid during gas chromatographic analysis was below 30 pmol using splitless-mode injection (SE-54 column). Filamentous fungal and procaryotic biomasses may be estimated simultaneously by using glucosamine and muramic acid biomass conversion factors in conjunction with this method.

The repetition effect in judgments of temporal duration across minutes, days, and months

Three experiments assessed the stability of the repetition effect in time judgment. In Experiment 1, subjects (N = 18) produced intervals ranging from 8 to 31 sec in a two-phase procedure with a five min rest between phases. In Experiment 2, subjects (N = 20) made verbal estimates of intervals ranging from 8 to 20 sec with a 48-hour delay between phases. Experiment 3 involved daily productions by three subjects of intervals ranging from 8 to 54 sec over several months. The slope of the psychophysical function increased across phases in Experimental 1, declined (as expected for estimation) across days in Experiment 2, and increased across months in Experiment 3. It was concluded that the repetition effect is relatively permanent and thus more similar to habituation than to sensory adaptation.

Lateralized Concomitants of Human Handedness

Literature was reviewed concerning lateral asymmetries of brain and behavior in normal and pathological populations of left-and right-handers. Cerebral asymmetries of structure and function are less pronounced in left-handers as a group than in right-handers as a group, and variability is greater in left-handers.

Vocal-Manual Trade-Offs In Hemispheric Sharing Of Human Performance Control

Experiment 1 established the linear ordering of performance and rated difficulty of three finger-sequencing tasks. Experiment 2 embedded these tasks within a dual-task paradigm employing vocalization of words and nonwords as concurrent activities. Concurrent vocal activity interfered with right-more than with left handed performance, and this lateralized interference effect increased monotonically with increased sequence difficulty. Results are discussed in terms of hemispheric sharing of dual task performance control.

Cecal necrosis after open-heart operation

Two patients with isolated transmural ischemic necrosis of the cecum after cardiopulmonary bypass are discussed. Superimposed upon the multiple cardiovascular abnormalities in these patients, cardiopulmonary bypass adds another risk factor for nonocclusive intestinal infarction. In patients undergoing open-heart procedures, postoperative nonspecific abdominal complaints should be evaluated with a high degree of suspicion for this lethal complication. An intensive diagnostic effort is indicated, including contrast and angiographic radiological studies. Consideration of early abdominal exploration is indicated.

Function of human platelets during extracorporeal circulation

The interaction between human platelets and nonbiologic surfaces was studied during in vitro recirculation of 500 ml of fresh, heparinized human blood in four different perfusion circuits. Circuits differed in surface area (0.1 m2 or 0.9 m2) and in surface composition. No important differences were observed between standard silicone-rubber and filler-free, silicone-rubber surfaces. Platelet counts decreased to 85% of control in 0.1- m2 circuits, but retained normal sensitivity to aggregating agents and released only small amounts of platelet factor 4 (PF4). In contrast, platelet counts in 0.9-m2 circuits decreased to 20% of control within 2 min and platelet sensitivity was depressed out of proportion to the fall in platelet count. Plasma PF4 progressively increased and platelet PF4 content progressively decreased during 6 h of recirculation. The results indicate that human platelets may exist in three conditions during extracorporeal circulation. Some platelets are unaltered, some are less sensitive to aggregating agents, and others have undergone extensive release. The ratio of blood volume to surface area appears to be an important determinant of platelet-surface interaction.

Successful treatment of varicella pneumonia with prolonged extracorporeal membrane oxygenation in a child with leukemia

A 5-year-old boy with acute lymphoblastic leukemia in complete continuous remission developed life-threatening varicella pneumonia and acute respiratory insufficiency (ARI). The child recovered after 92 hours of partial venoarterial perfusion with a membrane oxygenator. Functional asplenia developed. Serial pulmonary function tests after perfusion indicate moderately severe restrictive lung disease which has slightly improved during an 18 month period.

Prospective and retrospective judgments of time as a function of amount of information processed

The subjects, 120 college students, sorted cards for 42 sec with instructions to process 0, 1, or 2 bits of information per card (response uncertainty) and then were asked to make an absolute judgement of the interval's duration. Half of the subjects knew this judgement would be required before the interval (prospective paradigm); half did not (retrospective paradigm). Judged time was an inverse linear function of response uncertainty under the prospective paradigm, whereas no significant function was obtained under the retrospective paradigm.

Extracorporeal membrane oxygenation during bronchopulmonary lavage

Extracorporeal membrane oxygenation (ECMO) in a venoarterial perfusion circuit was used to provide support of gas exchange during bronchopulmonary lavage in a 32-year-old man with pulmonary alveolar proteinosis and severe arterial hypoxemia. Prior to the lavage, Pao2 during mechanical ventilation with 100% oxygen and positive end-expiratory pressure was only 125 mm Hg. Extracorporeal perfusion at a flow rate of 3 liters/min, with oxygen delivery of 244 ml/min, increased the Pao2 to 227 mmHg and lowered the mean pulmonary artery pressure from 28 to 24 mm Hg. During bronchopulmonary lavage and ECMO, the Pao2 ranged between 46 and 96 mm Hg. After the procedure, pulmonary performance decidely improved. By reducing the chances of fatal hypoxemia, ECMO allowed treatment to be instituted for this potentially reversible disorder and proved helpful as a form of support during the management of pulmonary alveolar proteinosis when severe hypoxemia may have other wise precluded bronchopulmonary lavage.

Human handedness: a partial cross-fostering study

The hand preference of college students correlated significantly with the writing hand of their biological parents but not that of their stepparents. The results are consistent with a genetic theory of the origin of human handedness.

Changes in extravascular lung water during venovenous perfusion

The accumulation of extravascular lung water was related to changes in plasma colloid osmotic pressure and pulmonary hydrostatic pressures in 12 normal dogs and 13 dogs that had venovenous perfusion for 2 hours at 45 to 70 ml. per kilogram per minute. The venovenous perfusion system included a membrane oxygenator and a roller pump. Net intravascular filtration pressure was calculated from plasma colloid osmotic pressure and pulmonary hydrostic pressures. Rapid accumulation of extravascular lung water occurred in control and bypass animals when net intravascular filtration pressure exceeded zero. At lower filtration pressures, venovenous perfusion did not affect accumulation of extravascular lung water.

Lateral asymmetry of retroactive inhibition in a psychomotor skill

Right-handed college students (N equals 160) received 10 practice trials on inverted-reversed printing with either the left or right hand followed by 10 additional trials with either the same or the other hand. Half the Ss then received 10 interpolated learning trials of inverted-but-nonreversed printing, while the other half of the Ss worked arithmetic problems. Significant retroactive inhibition occurred for Ss printing with the right hand, but not for Ss printing with the left hand.

Echocardiographic recognition of the mitral valve-posterior aortic wall relationship

Aortic-mitral valve discontinuity has previously been described in double outlet right ventricle, endocardial cushion defect, single ventricle, tetralogy of Fallot, and prolapse of the mitral valve. We are reporting two additional examples of aortic-mitral valve discontinuity including 15 cases of gross left ventricular dilation and a case of acute pneumococcal bacterial endocarditis with a large subannular erosion. While nonspecific, aortic-mitral valve discontinuity is a clinically important sign that should be sought with slow-M-mode scanning and strip chart recording.

Intrahemispheric response competition between vocal and unimanual performances in normam adult human males

Subjects balanced a dowel rod vertically on the left and right index finger singly and while simultaneously repeating phrases. With right-handed subjects who had no left-handed relatives, concurrent verbalization shortened right- but not left-handed balancing. Increased phonetic difficulty of the phrases produced an increased decrement on right-handed balancing, but left-handed balancing was unchanged; it also produced more verbalization errors on trials with the right hand, but not with the left. Concurrent verbalization shortened balancing duration with both hands of left-handers. Right-handers with left-handed relatives produced variable results. Concurrent humming also selectively interfered with right-handed balancing. It was concluded that the results conform to an interpretation based on intrahemispheric interference between incompatible, simultaneously produced sets of responses.