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Biomedical subjects

E W Becker

Publications and source records attributed to E W Becker.

33 records · Page 2Linked to original sources
PubMed1992

Distribution of the PBC-specific- (M2) and the naturally-occurring mitochondrial antigen- (NOMAg) systems in plants.

In previous studies it was demonstrated that antibodies in sera from patients with primary biliary cirrhosis (PBC) and their relatives can recognize two different antigen systems in the ATPase fraction prepared from beef heart mitochondria, namely the PBC-related M2- and the naturally occurring mitochondrial antigen (NOMAg)-related epitopes. Since separation of these two antigen systems could not be achieved using mammalian mitochondria, mitochondria from a wide spectrum of plants were analysed with respect to the presence of mitochondrial antigens. Mitochondria from 29 species of plants were prepared and tested by ELISA and Western blot using marker sera from patients with PBC reacting in the Western blot with M2a,b,c,d (alpha-ketoacid-dehydrogenase complex) and NOMAg-specific sera recognizing the three major epitopes epsilon, zeta, and eta at 65, 61 and 58 kD. Naturally occurring mitochondrial antibody (NOMA)-positive marker sera reacted in the ELISA with mitochondria from all plants, and the zeta/eta positive sera gave also a positive reaction at 61/58 kD in the Western blot while the epsilon epitope could not be visualized by this method. In contrast, the M2 antigen was detected preferentially in lower plants such as algae, fungi, and ferns. Analysing these data with respect to the evolution of proteins one would have to assume that the M2 antigen was lost in most higher plants or underwent some structural alterations. Furthermore, considering the fact that the M2- and the NOMAg-related epitopes could be only partially separated, i.e. there were no plant mitochondria showing only M2 but no NOMAg, one could speculate that anti-M2 antibodies are derived from the pool of naturally occurring antibodies.

Antigens↗
PubMed1991

Efficiency of muscle contraction. The chemimechanic equilibrium.

Although muscle contraction is one of the principal themes of biological research, the exact mechanism whereby the chemical free energy of ATP hydrolysis is converted into mechanical work remains elusive. The high thermodynamic efficiency of the process, above all, is difficult to explain on the basis of present theories. A model of the elementary effect in muscle contraction is proposed which aims at high thermodynamic efficiency based on an approximate equilibrium between chemical and mechanical forces throughout the transfer of free energy. The experimental results described in the literature support the assumption that chemimechanic equilibrium is approximated by a free energy transfer system based on the binding of divalent metal ions to the myosin light chains. Muscle contraction demonstrated without light chains is expected to proceed with a considerably lower efficiency. Free energy transfer systems based on the binding of ions to proteins seem to be widespread in the cell. By establishing an approximate chemimechanic equilibrium, they could facilitate biological reactions considerably and save large amounts of free energy. The concept of chemimechanic equilibrium is seen as a supplementation to the concept of chemiosmotic equilibrium introduced for the membrane transport by P. Mitchell.

Adenosine Triphosphatases↗
PubMed1988

[Pericardial effusion during the therapy of Crohn's disease with 5-aminosalicylic acid].

A 22-year-old woman with Crohn's disease was treated with 5-aminosalicylic acid (Claversal), four times 500 mg daily, because of increased inflammatory activity. Retrosternal pain set in after two weeks; in another two weeks a moderately enlarged heart was noted on the chest X-ray and pericardial effusion diagnosed echocardiographically. After stopping the medication the pericardial effusion resolved without further treatment. Immunoserology failed to demonstrate autoantibodies, but a repeat lymphocyte stimulation test was positive. There is a possible causal relationship between 5-aminosalicylic acid medication and the pericardial effusion, although the pathogenetic mechanisms is not known.

Adult↗
PubMed1988

[Demonstration by lymphocyte transformation test of the allergic genesis in a case of acute hepatitis].

After accidental re-exposure to metamizole a 50-year-old patient developed severe jaundice within five hours (total bilirubin 43.9 mg/dl) with a rise of GOT to 147, of GPT to 222, of gamma-GT to 380 and of alkaline phosphatase to 497 U/l. The allergic genesis of this reaction was demonstrated in the lymphocyte transformation test which, in the presence of the causative substance and its metabolites, was performed five times during a period of 232 days. The first three tests were positive with stimulation indices up to 2.3. Sensitization to the metabolite 4-aminoantipyrine was demonstrated: this is known to be the first of four metabolites formed within 1-1 1/2 hours and constituting 40% of the four metabolites in the blood.

Acute Disease↗
PubMed1988

[Cefotaxime-induced allergic agranulocytosis in an acute attack of serologically atypical primary biliary cirrhosis].

A 35-year-old woman developed pharyngitis with high fever and painful joint swellings. A severe cholestatic hepatitis occurred 40 days later with a rise of bilirubin to 32 mg/dl. "Nuclear dot" antibodies were demonstrated in the immunofluorescence test on cell cultures, confirming a diagnosis of primary biliary cirrhosis which had followed an atypical course. After nine days of cefotaxime administration, commenced because of persistent fever of 40 degrees C, an agranulocytosis was demonstrated, which regressed within a week of discontinuing the drug. The allergic genesis of the agranulocytosis was proven by repeated lymphocyte stimulation tests in the presence of cefotaxime. The autoimmune hepatitis was probably a predisposing factor in the genesis of the allergically induced agranulocytosis.

Acute Disease↗
PubMed1977

Feelings of hostility and personal control as related to depression.

The relationships among depression, hostility, and locus of control were investigated in 58 clinic outpatients. Depth of depression was correlated positively with both covert hostility and external control, while external control correlated with covert hostility. Analysis of subscales on the hostility inventory indicated that overt forms of hostility were unrelated to depression, while the subscales of guilt, resentment, irritability, and suspicion were related positively (r = .50, p less than .005). Partial correlations suggested that the relationship between depression and external control may depend on the presence of resentment and irritability and that a combination of these covert factors with external control commonly is found in depression.

Adjustment Disorders↗
PubMedDate not supplied

Dynamics and kinetics of enzymes. Kinetic equilibrium of forces in biochemistry.

To explain the high specificity, high reaction rate, and high thermodynamic efficiency in enzymatic processes, cooperation of the enzyme with a molecular transfer unit is assumed. A "kinetic equilibrium of forces" is suggested, which enables high reaction rates to occur under equilibrium conditions and a thorough examination of the substrate to be made without consumption of free energy. In case of ATPases, ion-binding proteins are the most probable transfer units. By analyzing the elementary effect in muscle contraction it is shown that the new theorem may be of substantial value in elucidating biochemical processes.

Actins↗
PubMedDate not supplied

California residential air exchange rates and residence volumes.

UNLABELLED: Air exchange rate data from two residential indoor air quality studies are presented. In the first investigation, over 500 residences in Southern California were sampled for three one-week periods from 1984 to 1985. Those data provided seasonal information for a broad range of residential characteristics in a large metropolitan area. In the second study, a probability sample of nearly 300 residences were sampled for a two-day period during the winter of 1991-1992 throughout the state of California. Air exchange rate is summarized by season, geographic area, and appliance type. Residence volumes are presented by cooking and heating appliance. The data approximately followed lognormal distributions. IMPLICATIONS: Indoor air quality and human exposure models often require estimates of air exchange rate and residence volumes. Application of those models to California residences can be improved by using the data distributions provided in this manuscript. Data distributions presented for heating and cooking appliances are useful for modeling the impact of indoor sources specific for those appliance types. Measured air exchange rate is also useful for modeling energy use for heating and cooling in residences.

Air Pollution, Indoor↗