Classification of malnutrition by statistical analysis of quantitative two-dimensional gel electrophoresis of plasma proteins

An attempt to use the relative concentrations of major plasma proteins for clinical assessment of severe malnutrition is described. Quantitative two-dimensional gel electrophoresis was used to measure the concentrations of 24 major proteins in small aliquots of plasma obtained from children, aged 0 to 3 years, who were patients and outpatients in Liberian hospitals. Fifteen had a clinical diagnosis of kwashiorkor, 36 were diagnosed with marasmus, and 18 were controls. There were also 5 controls from the United States. The individuals were placed in six groups; kwashiorkor, kwashiorkor who died during treatment, marasmus, marasmus who died, Liberian controls, and U.S. controls. The amount of protein in each spot in the two-dimensional gels was estimated by measuring bound stain using a laser scanner and computerized image analysis. We found very low serum transferrin levels in malnourishment, in agreement with reports from other investigators. All of the data for 24 protein variables were pooled for factor analysis; the mean factor scores for each group differed, with the kwashiorkor groups furthest from the controls. Results of discriminant analysis using the amounts of different numbers of protein variables (3 to 24) were compared for posterior assignment of individuals to groups. The validity of the method was tested by analysis of plasma aliquots obtained from patients following initiation of therapy and which were not a part of the training set. Predictive performance (prognosis of patient survival) depended upon the number of protein variables used. Although artifactual fitting of the data is expected to contribute to performance as the number of variables is increased, use of as many as 7 variables may be justified, even with our small patient groups. Possible use of these results for development of a practical clinical test is discussed.     

Computer-assisted diagnosis of acute azotemia

We designed a computer program to make diagnostic suggestions in cases of acute azotemia. The performance of the program was tested in a retrospective manner on 63 patients with acute azotemia. The program correctly identified 90 of 94 diagnoses and made 20 false positive diagnostic suggestions. A revised version of the program correctly identified 94 of 94 diagnoses and made 4 false negative suggestions. The justification for this kind of diagnostic aid is discussed.     

Parallel exponential queues with dependent service rates

A system of two parallel single-server exponential queues is considered. These queues operate independently except that the service rate in each queue changes whenever the other queue is empty. By treating one of the queues as bounded, this model can be shown to have a matrix-geometric steady state vector which can be computed efficiently. Algorithms are also developed to compute the characteristics of the departure stream of customers from each queue. Some numerical results are presented, and based on these results an efficient approximation scheme for the system is developed which may possibly be extended to systems with more than two parallel queues.     

Qualitative analysis of one class of population models with commensal interaction

The qualitative analysis of a class of dynamic population models that are in commensal relationships and compete for one substrate is carried out. The stability of all the stationary conditions is analyzed. All the singularities are found analytically and constraints are obtained for species growth characteristics and initial flows of the substrate and product. The qualitative changes in the dynamics due to variations of several system parameters are analyzed and bifurcation diagrams are constructed for all the singular points.     

An integrated research tool for X-ray imaging simulation

This paper presents a software simulation package of the entire X-ray projection radiography process including beam generation, absorber structure and composition, irradiation set up, radiation transport through the absorbing medium, image formation and dose calculation. Phantoms are created as composite objects from geometrical or voxelized primitives and can be subjected to simulated irradiation process. The acquired projection images represent the two-dimensional spatial distribution of the energy absorbed in the detector and are formed at any geometry, taking into account energy spectrum, beam geometry and detector response. This software tool is the evolution of a previously presented system, with new functionalities, user interface and an expanded range of applications. This has been achieved mainly by the use of combinatorial geometry for phantom design and the implementation of a Monte Carlo code for the simulation of the radiation interaction at the absorber and the detector.     

Calorimetric and thermodynamic analysis of palladium-deuterium electrochemical cells

An analysis is made of the chemical heats liberated from a palladium-deuterium electrochemical cell operating inside a calorimeter. It is important, in such an analysis, to carefully identify the chemical and electrochemical sources of heat, before any “excess heats” can be ascribed to non-chemical reactions.⁽¹⁾ The calorimeter measures the enthalpy (ΔH _r ) of the reaction; whereas, the electrochemical voltage of the cell reflects the free energy (ΔG _r ) of the reaction within the Pd-D electrolysis cell. The heat energy from the calorimeter cell therefore doesnot equal the electrical energy supplied to the cell, as might initially be expected. The magnitudes of the differing calorimetric and electrochemical energies were found to be related through the “thermoneutral potential” (ξ_H) of the electrochemical reaction. The chemical heat theoretically expected from the calorimeter is given by (1) I(ξ_L-ξ_H), the cell current (I), multiplied by the difference between the operating cell voltage (ξ_L) and the thermoneutral potential (ξ_H), rather than (2) Iξ_L, the electrical input power. This was verified empirically using a freon vaporization calorimeter, which operates on the principle of accurate measurement of the vaporization rate of liquid freon which completely surrounds the electrochemical cell. The calorimetrically-measured heats observed from a Pt/D₂O, 0.1M LiOD/Pd electrochemical cell were within 2% of the thermoneutral potential predicted value, I(ξ_L-ξ_H); but were found to be 15–30% less than the electrical work supplied to the cell, Iξ_L. Measurements of D₂O consumed by the cell reactions also verified that essentially no significant recombination of D₂ and O₂ gases occurred within the cell. No “excess heats” were observed from this Pd cell during the 36 days of its electrolytic operation. Likewise, no increase in the neutron flux around the cell was found, using three³He radiation detectors.     

Effects of rilmenidine (hyperium) on lipid balance in hyperlipidemic hypertensive patients. Randomized, controlled, double-blind 8-week study vs. captopril in parallel groups

Rilmenidine (dose of 1 mg once or twice a day) is the first oxazoline compound with antihypertensive properties. Its effects on lipid parameters [total cholesterol, HDL and LDL fractions, triglycerides, apolipoprotein A1 and B, lipoprotein (a)] were compared under double-blind conditions and in parallel groups to those of captopril (50 to 100 mg per day, in 2 divided doses) over a period of 8 weeks, in 51 hyperlipidaemic hypertensive patients [age: 56.3 +/- 1.5 years, systolic and diastolic blood pressure (SBP/DBP): 165.1 +/- 2.0/99.1 +/- 0.6 mmHg, LDL cholesterol: 5.38 +/- 0.16 mmol/L]. No significant difference was demonstrated between the groups on inclusion for any of the clinical parameters (SBP, DBP, heart rate (HR)) and laboratory parameters, apart from apolipoprotein A1, for which the mean value was higher in the rilmenidine group than in the captopril group (p < 0.05). No difference between the groups was demonstrated during the 8 weeks of treatment for the course of blood pressure: SBP and DBP decreased by 20.5 and 13.9 mmHg, respectively, in the rilmenidine group and by 21.3 and 13.1 mmHg in the captopril group (no significant difference: NS). HR decreased by 0.3 beats per minute (bpm) in the rilmenidine group and by 4.1 bpm in the captopril group (NS). No statistically significant difference in lipid parameters was observed between the two groups. No clinically significant variation in any of the lipid parameters was observed after 8 weeks of treatment with rilmenidine or captopril. These results confirm the antihypertensive efficacy and neutrality of rilmenidine on lipid metabolism over a period of 8 weeks. Rilmenidine therefore represents a useful alternative in the first-line treatment of hypertension in hyperlipidaemic hypertensive patients.     

Corrosion of tungsten-base pseudoalloys in elegas

Conclusions Pseudoalloys based on tungsten and copper (silver) possess good resistance to corrosion by dry elegas, and may be recommended for the manufacture of electrical parts intended for operation in hermetic systems filled with elegas. In humid elegas pseudoalloys based on tungsten and copper (silver) become covered with films forming by the reactions of the surfaces of these materials with water and the hydrolysis products of impurities in elegas.Translated from Poroshkovaya Metallurgiya, No. 10(214), pp. 40–43, October, 1980.     

Dietetic study of pregnant women of Santa Maria Cauqué, Guatemala. I. Variability of protein indicators and analysis by the time of meals

The distribution of the protein energy ratio indicators (Pe%), amino acid score and protein value (NDpCal%) in the three daily meals (breakfast, lunch and dinner) of the diet of pregnant women from Santa María Cauqué, Guatemala, was studied. The results were compared with those obtained for the total daily food intake. The differences observed were not significant, confirming the validity of the determination of amino acid score, Pe% and NDpCal% in the foods consumed during the whole day in this type of populations. It also reflects the nutritional benefit of the food pattern, since protein utilization would not be decreased by a different distribution of protein quality and concentration throughout the three daily meals. The variability among individuals of Pe% intake, amino acid score and NDpCal% gave the following values: 16.0, 9.3 and 15.6, respectively. It is noteworthy to add that the variability of Pe% observed is similar to that reported for populations of developed countries.