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Biomedical subjects

C Levi

Publications and source records attributed to C Levi.

29 records · Page 2Linked to original sources
PubMed1980

Mycotoxins in coffee.

This report reviews studies concerning the susceptibility of green coffee beans to mycotoxin contamination. Included are investigations on normal mold flora, toxin production in inoculated beans, effect of experimental roasting on aflatoxin, ochratoxin, and sterigmatocystin, and survey on the presence of these toxins in commercial green coffee. Because of the extremely low frequency of findings, the low levels of toxins, and the experimental data showing 70--80% destruction by the roasting process of toxin added to green coffee, further study on this topic has been discontinued.

Coffee↗
PubMed1978

[Medullary plasmocytosis in urologically silent Grawitz' tumor].

Three cases of urologically silent Grawitz' tumour detected by a pathological blood picture marked by marrow plasmacytosis are presented. The importance of paraneoplastic syndromes in this tumour form is discussed. The association observed is common and its classification as a paraneoplastic syndrome is examined.

Adenocarcinoma↗
PubMed1978

Amylopectin degradation in pea chloroplast extracts.

Phosphorolysis rather than phosphorylation of amylolysis products was found to be the major pathway of sugar phosphate formation from amylopectin by pea (Pisum sativum L.) chloroplast stromal proteins. The K(m) for inorganic phosphate incorporation was 2.5 mm, and ATP did not stimulate amylopectin-dependent phosphate incorporation. Arsenate (10 mm) inhibited phosphate incorporation into glucose monophosphates up to 46% and phosphoglucomutase activity 96%, resulting in glucose 1-phosphate accumulation as a product of amylopectin degradation. The intracellular distribution of enzymes of starch utilization was determined. Phosphorylase, phosphoglucomutase, and hexokinase were found in the chloroplast and cytoplasm, while beta-amylase was restricted to the cytoplasm. Maltase was not detectable; maltose phosphorylase was active in the chloroplast.

Journal Article↗
PubMed1978

Malate synthesis by dark carbon dioxide fixation in leaves.

The rates of dark CO(2) fixation and the label distribution in malate following dark (14)CO(2) fixation in a C-4 plant (maize), a C-3 plant (sunflower), and two Crassulacean acid metabolism plants (Bryophyllum calycinum and Kalanchoë diagremontianum leaves and plantlets) are compared. Within the first 30 minutes of dark (14)CO(2) fixation, leaves of maize, B. calycinum, and sunflower, and K. diagremontianum plantlets fix CO(2) at rates of 1.4, 3.4, 0.23, and 1.0 mumoles of CO(2)/mg of chlorophyll. hour, respectively. Net CO(2) fixation stops within 3 hours in maize and sunflower, but Crassulaceans continue fixing CO(2) for the duration of the 23-hour experiment.A bacterial procedure using Lactobacillus plantarum ATCC No. 8014 and one using malic enzyme to remove the beta-carboxyl (C(4)) from malate are compared. It is reported that highly purified malic enzyme and the bacterial method provide equivalent results. Less purified malic enzyme may overestimate the label in C(4) as much as 15 to 20%.The contribution of carbon atom 1 of malate is between 18 and 21% of the total carboxyl label after 1 minute of dark CO(2) fixation. Isotopic labeling in the two carboxyls approached unity with time. The rate of increase is greatest in sunflower leaves and Kalanchoë plantlets. In addition, Kalanchoë leaves fix (14)CO(2) more rapidly than Kalanchoë plantlets and the equilibration of the malate carboxyls occurs more slowly. The rates of fixation and the randomization are tissue-specific. The rate of fixation does not correlate with the rate of randomization of isotope in the malate carboxyls.

Journal Article↗
PubMed1977

Screening for hearing impairment in early childhood.

Hearing screening for early detection of deafness in children was carried out in the Jerusalem area during 5 years (1967-1972). Approximately 27,000 infants 5-7 months old, representing 85% of the children population at this age, were screened in baby clinics and a selective 'at risk' register was applied to them. Testing hearing in baby clinics was easy to implement and economical but not infallible. About 50% of the 43 hearing-impaired children were identified during the 1st year of their life at an audiology center. A careful and efficient screening and follow-up could identify 70% of the deaf children. We recommend to apply the hearing screening and selective 'at risk' register to children 7-10 months old. It is suggested to expand hearing screening to 2- to 3-year-old children.

Deafness↗
PubMed1976

Starch degradation in isolated spinach chloroplasts.

A method for loading isolated intact spinach (Spinacia oleracea L.) chloroplasts with (14)C-starch is described. These intact chloroplasts were incubated aerobically in the dark for 30 minutes. Radioactivity in starch declined and glyceric acid 3-phosphate and maltose were the major radioactive products. It is proposed that starch is degraded within the chloroplast to glyceric acid 3-phosphate and to maltose.

Journal Article↗
PubMed1976

Regulatory Properties of the ADP-Glucose Pyrophosphorylase of the Blue-Green Bacterium Synechococcus 6301.

ADP-glucose was found to be the primary sugar nucleotide used for glycogen synthesis by Synechococcus 6301. ADP-glucose pyrophosphorylase was partially purified 12-fold from this blue-green bacterium. The enzyme was activated 8- to 25-fold by glycerate 3-phosphate. Fructose 6-phosphate, fructose 1,6-bisphosphate, 5'-adenylate, and adenosine diphosphate activated the enzyme, but less than glycerate 3-phosphate. The enzyme was inhibited by inorganic phosphate. The I(0.5) of phosphate was 0.072 mm, and in the presence of 2 mm glycerate 3-phosphate, increased to 1.8 mm. The substrate saturation curves for glucose 1-phosphate and ATP were hyperbolic in both the presence and absence of glycerate 3-phosphate or phosphate. The saturation curve for MgCl(2) was sigmoidal; 2 mm glycerate 3-phosphate decreased the sigmoidicity from a Hill slope n value of 5.6 to 2.8, and increased the MgCl(2) optimum from 3 mm to 6 to 7 mm.

Journal Article↗
PubMed1975

Carbon dioxide fixation in isolated kalanchoe chloroplasts.

Chloroplasts isolated from Kalanchoe diagremontiana leaves were capable of photosynthesizing at a rate of 5.4 mumoles of CO(2) per milligram of chlorophyll per hour. The dark rate of fixation was about 1% of the light rate. A high photosynthetic rate was associated with low starch content of the leaves. Ribose 5-phosphate, fructose 1,6-diphosphate, and dithiothreitol stimulated fixation, whereas phosphoenolpyruvate and azide were inhibitors. The products of CO(2) fixation were primarily those of the photosynthetic carbon reduction cycle.

Journal Article↗
PubMedDate not supplied

Ciliated hepatic foregut cysts: US, CT, and contrast-enhanced MR imaging.

Hepatic foregut cysts are uncommon lesions of the liver. In this report we prospectively examined two patients by means of computed tomography (CT), ultrasound, and contrast-enhanced magnetic resonance imaging. Ciliated hepatic foregut cysts were subsequently demonstrated in both patients following CT-guided biopsy. Magnetic resonance imaging was found to be useful in differentiating these cysts from other lesions.

Aged↗