Pattern-Based Interactive Diagnosis of Multiple Disorders: The MEDAS System

A knowledge-based interactive sequential diagnostic system is introduced which provides for diagnosis of multiple disorders in several body systems. The knowledge base consists of disorder patterns in a hierarchical structure that constitute the background medical information required for diagnosis in the domain under consideration (emergency and critical care medicine, in our case). Utilizing this knowledge base, the diagnostic process is driven by a multimembership classification algorithm for diagnostic assessment as well as for information acquisition [1]. A key characteristic of the system is congenial man-machine interface which comes to expression in, for instance, the flexibility it offers to the user in controlling its operation. At any stage of the diagnostic process the user may decide on an operation strategy that varies from full user control, through mixed initiative to full system control. Likewise, the system is capable of explaining to the user the reasoning process for its decisions. The model is independent of the knowledge base, thereby permitting continuous update of the knowledge base, as well as expansions to include disorders from other disciplines. The information structure lends itself to compact storage and provides for efflcient computation. Presently, the system contains 53 high-level disorders which are diagnosed by means of 587 medical findings.

Ultraviolet Photometer Observations of the Saturnian System

Several interesting cloud and atmospheric features of the Saturn system have been observed by the long-wavelength channel of the two-channel ultraviolet photometer aboard the Pioneer Saturn spacecraft. Reported are observations of the most obvious features, including a Titan-associated cloud, a ring cloud, and the variation of atmospheric emission across Saturn's disk. The long-wavelength data for Titan suggest that a cloud of atomic hydrogen extends at least 5 Saturn radii along its orbit and about 1.5 Saturn radii vertically. A ring cloud, thought to be atomic hydrogen, has also been observed by the long-wavelength channel of the photometer; it shows significant enhancement in the vicinity of the B ring. Finally, spatially resolved observations of Saturn's disk show significant latitudinal variation. Possible explanations of the variation include aurora or limb brightening.

Studies of colloid osmotic pressure in pregnancy-induced hypertension

Pulmonary edema, although infrequently encountered, may cause death in severe cases of PIH. The mechanisms that account for edema in these instances are unclear. With a transducer-membrane system to directly measure serum COP, 22 patients with PIH were compared to 23 normal pregnant patients at term. In the PIH group the antepartum and postpartum COP values were significantly lower (17.9 and 13.7 mm Hg, respectively) than comparable values for the control group (22.0 and 17.2 mm Hg, respectively). Two patients in the PIH group in whom the antepartum COP values were 13.1 and 14.7 mm Hg exhibited clinical and radiographic evidence of pulmonary edema. Pulmonary artery wedge pressure (PAW) recorded in one patient with pulmonary edema was only moderately elevated to 18 mm Hg. We believe that serial COP determinations combined with pulmonary artery pressure monitoring may be helpful to guide fluid therapy in critically ill patients with PIH.

Treatment of circulatory shock with dopamine. Studies on survival

Therapeutic effects of dopamine hydrochloride on the peripheral and metabolic defects of shock were investigated in 34 patients with circulatory shock associated with myocardial infarction, bacteremia, or hypovolemia. Severity of the circulatory defect characterized by hypotension, reduced cardiac output, oliguria, and notably reduced skin (toe) temperature before treatment with dopamine was not directly related to survival. However, the arterial blood concentration of lactate before treatment with dopamine indicated the likelihood of survival. Patients who ultimately survived following treatment with dopamine had normal or only mildly elevated levels of arterial blood lactate before therapy. No patients with established shock states in whom perfusion failure was associated with substantial increases in the level of arterial blood lactate survived regardless of treatment with dopamine. Increases in toe temperature during dopamine treatment also emerged as a uniquely good indicator of favorable outcome during therapy.

Pulmonary edema following intracranial hemorrhage

Hemodynamic changes and samples of fluid from pulmonary edema were studied in a 50-year-old woman who developed florid pulmonary edema following intracranial hemorrhage. Marked systemic and pulmonary arterial hypertension were associated with the rapid production of edema fluid that contained red blood cells, but had a lower protein content than plasma. After restoration of pulmonary vascular pressures to a normal range, the production of fluid ceased, and clinical signs of edema resolved. These findings point to the sudden increase in pulmonary microvascular pressure as the cause of pulmonary edema in this patient. Our findings contrast with those of previous reports and with speculations on the extent of a defect in permeability accounting for pulmonary edema following injury to the brain.

Dimensionality of the repression sensitization scale

Study of the internal structure of the R-S Scale failed to support a finding of unidimensionality or bipolarity, as theory suggests. A factor analysis of the item matrix revealed a poorly defined multifactor structure that contained five relatively weak unipolar factors (N = 200). Guttman's Reproducibility and the Kuder-Richardson Coefficient adjusted for test length similarly failed to support the presence of a unifactor structure. The relatively high Coefficient of Dimensionality was rejected as evidence of unidimensionality given the uncertainty over what psychometric properties this index reflects. The high proportion of S-item interaction variance showed considerable equivocal item content, which suggested marked error factors due to Ss' idiosyncratic interpretation of items.

Host-Symbiont Interactions: III. Purification and Partial Characterization of Rhizobium Lipopolysaccharides

The lipopolysaccharides of three strains each of Rhizobium leguminosarum, R. phaseoli, and trifolii have been purified and partially characterized. The last step in the purification procedure is gel filtration column chromatography using Sepharose 4B with an elution buffer consisting of ethylenediaminetetraacetic acid and triethylamine. Each of the lipopolysaccharides reported in this paper elutes as a symmetrical peak in the partially included volume of this Sepharose 4B column. The ratio of 2-keto-3-deoxyoctonate acid (a sugar which is characteristic of lipopolysaccharides) to hexose is constant throughout the carbohydrate-containing peaks as they elute from the Sepharose 4B. The compositions and immunodominant structures of the purified lipopolysaccharides vary as much among strains of a single Rhizobium species as among the different species of Rhizobium. There is no obvious correlation between the nodulation group to which a Rhizobium belongs and the chemical composition or immunochemistry of the Rhizobium's lipopolysaccharide. There is extensive crosslysis by phage of strains of R. trifolii, R. phaseoli, and R. leguminosarum. This suggests that the receptors for these cross-lysing phage reside either in nonlipopolysaccharide structures or in common structures within the lipopolysaccharide which are not detected by compositional or immunochemical analysis.

MMPI content and repression-sensitization scales

The commonality between the findings of the Repression-Sensitization Scale research and the factor structure of the Wiggins MMPI Content Scales suggested the use of these scales for further investigation of Repression-Sensitization Scale constructs. As predicted, Repression-Sensitization was found highly related to those Content Scales describing psychological maladjustment, ego control, and somatic distress. Religious Fundamentalism and Femininity content scales were found unrelated to Repression-Sensitization. Male sensitizers showed a tendency to score higher on the Authority Conflict Scale than female sensitizers. Subjects were 50 male college students and 50 female students.

Colloid osmotic and pulmonary wedge pressures in acute respiratory failure following hemorrhage

Acute respiratory failure evolved in five patients following hypovolemic shock related to trauma or surgical operation, or both. A reduction in colloid osmotic pressure, increases in pulmonary artery wedge pressure and reductions in colloid osmotic pressure-pulmonary artery wedge pressure gradient to levels which are likely to account for pulmonary edema were observed. Accordingly, reduction in the colloid hydrostatic pressure gradient may, in part, explain the development of acute respiratory failure after acute blood loss. In one instance, however, the absence of such reduction in the colloid osmotic pressure-pulmonary artery wedge pressure gradient together with increases in pulmonary vascular resistance showed that colloid osmotic pressure and pulmonary artery wedge pressure are not exclusively operative in the pathogenesis of the clinical syndrome of acute respiratory failure.

Effects of Aroclor® 1248 and 1260 on the Fathead Minnow (Pimephales promelas)

Fathead minnows were exposed to Aroclor® 1248 and 1260 in flow-through bioassays to determine the acute (30-d) and chronic (240-d life cycle) effects on the larvae and adults, as well as the bioconcentration of the mixtures of PCBs in the fish. Newly hatched larvae (< 8 h old) were the most sensitive; the calculated 30-d LC50 was 4.7 μg/L for Aroclor 1248 and 3.3 μg/L for Aroclor 1260. Reproduction in fathead minnows occurred at concentrations as high as 3 μg/L for Aroclor 1248 and 2.1 μg/L for Aroclor 1260, concentrations that significantly affected larval survival. The 20% reduction in the standing crop in the second-generation fish at concentrations as low as 0.4 μg/L was due to the death of the larvae soon after hatching. The bioconcentration factor for PCBs was independent of the PCB concentration in the water; in adult females at 25 °C it was ~ 1.2 × 105 for Aroclor 1248 and 2.7 × 105 for Aroclor 1260. Females accumulated about twice as much PCBs as the males because of the greater amount of lipid in the female. Exposed fish placed in untreated Lake Superior water eliminated < 18% of the body burden after 60 d. Key words: PCBs, bioassay, bioconcentration, chronic toxicity, embryo-larval, depuration

Images of Io's Sodium Cloud

The first direct images of Io's sodium cloud are reported and analyzed. The observed cloud extends for more than 10(5) kilometers along Io's orbit and is a somewhat "banana-shaped" partial toroid. More sodium atoms precede Io than follow it. A model based on the escape of sodium from a specific localized area on Io provides a reasonable fit to the observed intensity distribution whereas isotropic escape does not.

Bacterial shock

Bacterial shock due to Gram-negative bacilli is best managed by prompt control of the infection with appropriate antibiotics and surgical drainage or excision. Corticosteroids for purposes of controlling systemic reactions to bacteria and their toxins constitute adjunctive therapy. Volume repletion and respiratory support may be of the greatest importance for temporary support of these critically ill patients. Vasoactive drugs including dopamine and isoproterenol should be used very sparingly and only as very temporary expedients.

High output heart failure associated with pulmonary edema complicating hydatidiform mole

Detailed hemodynamic, metabolic and blood volume studies were performed in a patient with hydatidiform mole who developed pulmonary edema associated with a high cardiac output. Several factors including hyperthyroidism, hypervolemia, and the molar state probably contributed to the left ventricular failure in this patient. results of these studies suggest that patients with hydatidiform mole and pulmonary edema need correction of the hypervolemia as well as removal of the molar tissue.