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Biomedical subjects

S Levi

Publications and source records attributed to S Levi.

At least 145 records · Page 8Linked to original sources

Characteristics of ferritins in human milk secretions: similarities to serum and tissue isoferritins.

The ferritins present in the first day human colostrum and mature milk were compared with serum and tissue ferritins on the basis of their iron content, immunological reactivity and glycosylation. Both had a low iron content. The degree of glycosylation and immunochemical properties of colostrum ferritin showed strong similarities with serum ferritin. The isoelectric points and immunochemical properties of milk ferritin were similar to heart ferritin. The concentration of colostrum ferritin was more significantly correlated to body iron stores than milk ferritin.

Colostrum↗

Regulation of ferritin synthesis in malignant and non-malignant lymphoid cells.

The different amounts of H-rich and L-rich isoferritins found in malignant and non malignant lymphoid cells are accompanied by proportional variations in the relative quantity of messenger RNAs for the H and L subunits of ferritin. The correlation between levels of messenger RNAs and proteins suggests that the amount of messenger RNA plays an important role in ferritin biosynthesis in these cells. The enhanced expression of ferritin messenger RNAs in some neoplastic cells is not caused by gross alterations in the structure of ferritin genes.

Biopsy↗

Immunochemical characterization of human liver and heart ferritins with monoclonal antibodies.

A library of 27 murine monoclonal antibodies was obtained by using human liver and heart ferritins as immunogens. The specificity of the antibodies for the two ferritins and their subunits was studied with five different methods. The antibodies elicited by the liver ferritin bound preferentially the immunogen and were specific for the L subunit. Some antibodies elicited by the heart ferritin had characteristics similar to the anti-liver antibodies, other ones bound preferentially the heart over the liver ferritin and were specific for the H subunit. Only two antibodies were able to bind both ferritins and subunits. Some anti-H and anti-L chain antibodies were used to develop and compare four types of immunoassay to quantitate isoferritins. The results indicate that heart ferritin is immunologically more heterogeneous than liver, the H and L subunits having large immunological differences with few, if any, identical epitopes; and that that the architecture of the immunoassays have a strong influence on the crossreactivity of the antibodies with the two isoferritins, probably because H and L chains are not arranged randomly in the assembled protein.

Animals↗

Exposure to fluoride in the chemical industry.

Industries that use fluoride-containing materials are usually aware of their toxicity and adopt adequate medical measures. It has been found that workers in factories who have not been considered as subjected to fluorine hazard and therefore have not been controlled had significantly elevated urinary fluoride levels. Most workers in a medically controlled fertilizer plant had normal urinary levels. Maintenance workers were found to have higher values, up to 12 mg/liter.

Agriculture↗

Puncture of unilateral renal cyst in utero.

Although most authors do not recommend prenatal puncture of a unilateral single cystic renal mass, in case the contralateral kidney is normal and there is sufficient amniotic fluid, this case report shows that the procedure, which can be done very carefully under ultrasonic guidance, can be helpful in establishing the presumed diagnosis.

Drainage↗

Ferritins in malignant and non-malignant lymphoid cells.

Lymphoid cells from peripheral blood, thymus, malignant and non-malignant lymph nodes were analysed for ferritin content using radioimmunoassays specific for the 'acidic' H-subunit-rich and for 'basic' L-subunit-rich isoferritins, and the data were compared with the immunological characteristics of the cells. All tissues with high proportion of T or 'null' cells contained the lowest concentration of L-subunit-rich isoferritins, while the H-subunit-rich forms increased from low levels in the quiescent peripheral blood lymphocytes (PBL), to higher values in the immature and proliferating thymocytes and lymphoblasts, malignant or not. B-cell lymphomas contained concentrations of both ferritin types higher than those found in PBL. No significant difference was found in the isoferritin concentrations between non-malignant lymph nodes and tissues involved in Hodgkin's disease. These findings indicate that maturation stage, proliferative status and anatomical localization affect isoferritin expression in lymphoid cells.

Ferritins↗

Pathological pregnancies. Results of amniotic fluid studies and fetal outcome.

Late amniocenteses (greater than 20 weeks' gestation) were performed in 114 pregnancies with no a priori genetic risk, but referred because of abnormal clinical and/or ultrasound findings suggesting fetal malformations. Reasons for referral included polyhydramnios (51 cases), oligohydramnios (15 cases), fetal growth retardation (FGR) (16 cases) and abnormal fetal ultrasound findings excluding anencephaly (32 cases). In 42 of these cases, referral was motivated by a combination of the above abnormal findings. When polyhydramnios was the sole anomaly (25 cases), 5 fetuses were malformed (20%), abnormal fetal karyotype and/or elevated amniotic fluid alphafetoprotein (AFP) were demonstrated in 2 cases. Oligohydramnios was the sole anomaly in one case; the infant died of prematurity. Fetal growth retardation was the sole anomaly in 14 cases, 11 otherwise normal newborns were small for date, 2 died at birth and 1 was malformed (1/14, 7%). In this group all fetal karyotypes were normal and in 2 cases amniotic fluid AFP were increased. In the 32 pregnancies without abnormal amniotic fluid volume and/or FGR and with fetal malformation(s) suggested by ultrasound, all malformations except one (ovarian cyst possibly ruptured during birth) were confirmed at birth, amniotic fluid AFP was elevated, and/or karyotype was abnormal in 6 cases. In 42 pregnancies where more than one alarm sign was present, abnormal karyotype and/or elevated amniotic fluid AFP level were recorded in 21 of the 39 cases where amniocentesis was performed, 33 fetuses were malformed (79%) and 13 died in the perinatal period (31%). The high incidence of abnormal results of amniocentesis found in this survey of pathological pregnancies, particularly in those with multiple alarm signs, emphasizes the need for amniocentesis in these situations.

Congenital Abnormalities↗

The influence of purified recombinant human heavy-subunit and light-subunit ferritins on colony formation in vitro by granulocyte-macrophage and erythroid progenitor cells.

Purified recombinant human heavy subunit (rHF, acidic) and recombinant human light subunit (rLF, basic) ferritins were assessed for their effects in vitro on colony formation by normal human granulocyte-macrophage (CFU-GM) and erythroid (BFU-E) progenitor cells. The purity of the samples was confirmed by electrophoresis in both nondenaturing and denaturing conditions and silver staining. Concentrations of 10(-8) to 10(-10) mol/L rHF caused an approximately 40% significant decrease in colony formation. Some significant activity was detected at 10(-11) mol/L, and activity was lost at 10(-12) mol/L. In contrast, rLF had no significant activity at 10(-8) to 10(-16) mol/L. rHF was significantly active against mouse bone marrow CFU-GM to concentrations as low as 10(-8) to 10(-9) mol/L. The inhibitory activity of rHF was inactivated with three different monoclonal antibodies recognizing the heavy subunit of ferritin, but not with two monoclonal antibodies recognizing the light subunit of ferritin. The inhibitory activity of rHF was similar in the absence or presence of serum, monocytes, and T lymphocytes. We and others have shown an association of a glycosylated natural acidic isoferritin (AIF) with inhibitory activity, but since the rHF was expressed in Escherichia coli and did not bind to concanavalin A, glycosylation of AIF is not an absolute prerequisite for this activity. These results demonstrate that rHF has suppressive activity in vitro and substantiate our original observations using purified natural acidic isoferritins.

Animals↗

Effect of acidic and basic isoferritins on in vitro growth of human granulocyte-monocyte progenitors.

Acidic isoferritins have been previously found to be highly potent inhibitors of hematopoietic progenitors at concentrations of 10(-16) to 10(-18) mol/L, and it has been suggested that acidic isoferritin inhibitory activity plays a role in the regulation of normal hematopoiesis and also in the pathogenesis of leukemia. To characterize the ferritin species that affect the in vitro growth of human colony-forming unit-granulocyte-macrophage (CFU-GM), we tested different preparations of basic (L-subunit-rich) and acidic (H-subunit-rich) isoferritins. Three preparations of human liver (basic) ferritin did not show any effects on CFU-GM growth at concentrations up to 10(-9) mol/L, irrespective of the degree of glycosylation. Acidic isoferritins were purified both from HeLa cells and human heart. HeLa cell ferritin did not affect in vitro colony formation. One of two preparations of human heart ferritin, containing 5% glycosylated ferritin, showed a mean inhibition of 26% +/- 8% of the control at 10(-9) mol/L (P less than .02), whereas the other preparation, which contained no glycosylated ferritin, did not show any effect of CFU-GM growth. A preparation enriched for glycosylated acidic isoferritins from human heart was found to produce a mean inhibition of 32% +/- 11% of the control at 10(-9) mol/L (P less than .01), whereas another one was ineffective. A significant part of the inhibitory activity was removed by preincubation with the monoclonal antibody 2A4 directed against human heart ferritin. The present findings indicate that basic isoferritins, ie, the predominant ferritin type in human blood, have no effect on the growth of human CFU-GM, and this is in keeping with indirect clinical evidence. Inhibition of colony formation may be obtained by some preparations of acidic isoferritins that are rich in H subunits and bind to concanavalin A. The mechanism(s) responsible for this are not clear, but the effective concentrations are higher than those found in human blood both under normal conditions and in leukemia. At present, the physiologic significance of the observed inhibitory activity is uncertain.

Ferritins↗

Multiple mechanisms of iron-induced ferritin synthesis in HeLa cells.

Iron administration to HeLa cells stimulates the accumulation of H-subunit and L-subunit rich isoferritins at similar extent. The increase in both types of isoferritins is accompanied by an increase in the amount of messenger RNAs specific for H and L subunits. The increase in the amount of these messenger RNAs, which occurs in the nucleus as well as in the cytoplasm, is proportionately lower than the increase in the protein. These results, together with analysis of transcription in isolated nuclei indicate the existence of a mechanism of transcriptional control of ferritin synthesis, associated to the translational control described so far.

Cell Nucleus↗

Serum ferritin in type I diabetes.

The concentration and degree of glycosylation of serum ferritin was evaluated in type I male diabetic patients at different levels of glycaemic control. Serum ferritin did not appear to be affected by hyperglycaemia, but some patients undergoing photocoagulation had abnormally high levels of serum ferritin. The glycosylated, (concanavalin A binding), proportion of serum ferritin was essentially the same in the control and diabetic groups. The finding that hyperglycaemia does not affect the degree of enzymatic glycosylation of this serum protein is discussed.

Adolescent↗

A new provisional serovar of Shigella dysenteriae.

Bacterial isolates obtained in Israel from stool cultures of 17 sporadic cases of acute diarrhea during the years 1972 to 1980 and from 14 patients involved in an institutional outbreak in 1984 are described. These cultures gave the biochemical reactions and pathogenicity tests characteristics of the genus Shigella but failed to agglutinate, living or boiled, in any of the recognized or provisional Shigella antisera. All 31 cultures were biochemically and serologically identical, and owing to their inability to ferment mannitol, it is proposed that they be regarded as belonging to a new provisional serovar of Shigella dysenteriae. The strain I9809-73 is designated as the test strain for this new serovar.

Shigella dysenteriae↗

Activation of latent collagenase by serum proteinases that interact with immobilized immunoglobulin G.

It has been previously observed that collagen destruction occurs in the vicinity of immune complexes present in articular cartilages of patients with rheumatoid arthritis. When IgG is covalently linked to Sepharose it behaves as if it has reacted with an antigen to form an immune complex, in that it binds the complement component C1 from human serum. Other serum components also interact with this matrix, though their interaction may not be specific for IgG. Two of these components were shown to possess proteolytic activity, one being kallikrein and the other having the properties of plasmin. Both of the activities could activate latent human collagenase. Whilst the binding of the plasmin activity is probably nonspecific, the binding of the kallikrein activity may be selective for IgG (although it is not certain whether this binding is direct or indirect via another molecule). These results therefore suggest that active proteinases such as plasma kallikrein may be selectively concentrated on immune complexes in vivo, where they may locally activate latent proteinases such as collagenase thereby initiating tissue destruction.

Antigen-Antibody Complex↗

Analysis of morbidity and outcome of infants weighing less than 800 grams at birth.

To ascertain the morbidity, outcome, and prediction of survival of infants weighing less than 800 gm at birth, we reviewed all newborn and follow-up records for this group who were treated at The Medical Center between 1978 and 1981. Of the 71 infants in this category, 12 survived and underwent comprehensive evaluations between six and 36 months of age. Nine of the 12 infants had no abnormalities on neurologic examination; ten had developmental quotients greater than 70; one was severely visually impaired; and three had evidence of growth retardation. Factors correlating with nonsurvival included a birth weight of less than 700 gm, asphyxia, fused eyelids, hypothermia, and male sex. We conclude that, although mortality is high, survivors can have a satisfactory outcome.

Adult↗

[Value and indications for ultrasonographic determination of fetal sex].

From the end of the first trimester of pregnancy it is possible to recognize the sex of the fetus. The percentage with which this can be done rises progressively with the age of the fetus (from 29% at 18 weeks to 72% at 24 weeks), and with the experience of the operator. Errors are few; about between 1 and 2%. The number of errors in the ability to decide the sex is independent of which sex the fetus is. The body measurements show a difference between the made and the female fetuses which is statistically significant from the 20th week onwards. Growth tables which are specific for each sex can be made.

Female↗

Neurological maturation of the human fetus.

The study of body movements (gross, eye, breathing movements) by realtime echography and their computerized analysis the assessment of the maturation of the behavioural patterns in the human fetus in utero. From the 28 weeks of gestation, 3 patterns can be defined; they are comparable to the sleep stages described in the premature and fullterm newborn. Pathological cases are discussed separately.

Behavior↗

Fetal biometric data obtained in a sole population with emphasis to sex differences.

Several biometrical parameters have been studied on an homogeneous population sample of 7548 fetuses. The measurement of numerous body and organ sizes on a sole population of fetuses is the only method of considering fetal biometry as a whole and allowing study of the clinical value of some ratios, indices and products of dimensions (not discussed here). The possibility of referring to separate norms for male and female fetuses increases the discriminant power of biometry in detecting fetal growth.

Biometry↗