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Biomedical subjects

G Izak

Publications and source records attributed to G Izak.

At least 19 recordsLinked to original sources
PubMed1981

Diagnosis of iron deficiency anemia in a rural population of children. Relative usefulness of serum ferritin, red cell protoporphyrin, red cell indices, and transferrin saturation determinations.

The diagnostic usefulness in iron deficiency anemia of serum ferritin, red cell protoporphyrin (Epp), mean corpuscular volume, mean corpuscular hemoglobin (MCH), and transferrin saturation measurements has been studied in a population of 294 children aged 1 to 6 yr. Of the children studied 19% had hemoglobin below 11 g/dl. Iron deficiency, diagnosed by at least two abnormal independent laboratory parameters, was the cause of anemia in all except two cases. The Pearson correlation coefficient for hemoglobin was highest with MCH, followed in decreasing order of magnitude by MCV, Epp, transferrin saturation, and finally by ferritin. Sensitivity and specificity were highest for MCH and lowest for ferritin. Of anemic, iron deficient individuals 97 to 100% could be identified by low MCH, 88 to 100% by transferrin saturation, 66 to 83% by ferritin, and 61 to 74% by Epp. In contrast, only 0 to 6% of normal, nonanemic individuals had low MCH, 0 to 4% had high Epp, but 21 to 39% had low transferrin saturation and 25 to 39% had low ferritin. Although reduced serum ferritin in anemic individuals is good evidence of iron deficiency, a significant proportion of anemic iron-deficient patients is missed by this procedure rendering it less useful than other, less expensive laboratory methods.

Age Factors↗
PubMed1981

EA rosette formation: a simple means to increase sensitivity of the antiglobulin test in patients with anti red cell antibodies.

Erythrocyte antibody (EA) rosette formation with the Fc-receptor on the K-562 erythro-myeloid cell line was employed for the detection of subagglutinating amounts of Ig molecules bound to red cells. The sensitivity of this method exceeds that of the conventional direct and indirect antiglobulin tests without any alteration of the incubation media or pretreatment of red cells. The increased sensitivity did not diminish the specificity of the test, which can detect IgG, IgM and complement as well. This method may demonstrate the presence of antibodies on red cells in patients with suspected autoimmune haemolytic anaemia and negative antiglobulin test.

Anemia, Hemolytic, Autoimmune↗
PubMed1980

Continuous production of monoclonal rheumatoid factor by EBV-transformed lymphocytes.

Human B lymphocytes are immortalized by Epstein-Barr virus (EBV, ref. 1). The virus can be used to establish lymphoblastoid cell lines that produce and actively secrete specific antibodies. The original method, which we have used for various antigens is based on selection of the specific surface antigen receptor-positive lymphocytes from the peripheral blood lymphocytes of a donor who was previously sensitized to the corresponding antigen. Furthermore, by cloning the polyclonal anti-NNP cell line we have produced human monoclonal antibodies for the first time in vitro. About 5-20 microgram ml-1 stably produced specific antibody is obtained in the supernatant of the cell lines. This approach can be used for the in vitro production of monoclonal human autoimmune antibodies by EBV-immortalized lymphocytes from patients with autoimmune diseases. We demonstrate the continuous production in vitro of a monoclonal IgM and anti-IgG antibody (rheumatoid factor, r.f.) by a lymphoblastoid cell line established from a patient with rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1980

Human prothymocytes. Membrane properties, differentiation patterns, glucocorticoid sensitivity, and ultrastructural features.

Thymic precursor cells (prothymocytes) comprise a large proportion of the fetal thymic cell population, but are less frequently encountered in the postnatal thymus, where they compose < 1% of the entire population. In the present study we attempted to characterize a number of properties of the prothymocytes obtained from human fetal thymic tissues after depletion of the E-rosette thymocyes on a Ficoll-Hypaque gradient. The prothymocytes are larger than the thymocytes and show a different nuclear chromatin pattern. This subset of cells lacks the E-rosetting and natural-attachment capacities and, unlike thymocytes, does not bind the lectin peanut agglutinin. Human prothymocytes are highly sensitive to the in vitro cytolytic effect of hydrocortisone, whereas the thymocytes are resistant. Long-term in vitro culture of prothymocytes resulted in the expression of thymocyte characteristics together with a burst of mitotic activity. Results of this study indicate that the rate of the prothymocyte proliferation is regulated by the small thymocytes present in the same suspension.

Antigens, Surface↗
PubMed1980

The in vitro sensitivity of leukemic and normal leukocytes to hydrocortisone induced cytolysis.

A marked sensitivity of CLL lymphocytes to hydrocortisone in vitro was demonstrated in each of the 25 patients tested. The sensitivity was manifested by the eventual lysis of the affected cells. Malignant lymphocytes from 8 out of 14 ALL patients were found also to be in vitro sensitive, whereas CML cells, AML cells, normal BM cells, thymocytes, peripheral blood lymphocytes, and polymorphonuclear cells were resistant. Within a tested CLL lymphoid suspension it is proven that the hydrocortisone causes the specific lysis of the malignant cells leaving the normal lymphocytes undamaged. The cytolysis is not an immediate action, but is expressed within 7-8 hr of incubation. However, 30 min incubation with the hormone is sufficient for the cytolytic effect to occur 20 hr later. The possible mechanisms involved in the specific glucocorticoid induced cytolysis are discussed.

Adolescent↗
PubMed1980

Anemia among Druze children in the Golan Heights.

The prevalence and causes of anemia were studied in 294 Druze children aged 10 months to six years. The hemoglobin level was less than 11.0 g/dl in 19%; none of these anemic children had folate deficiency. Iron deficiency, diagnosed on the basis of abnormal values for at least two independent laboratory parameters, was the cause of anemia in all but two cases. The Pearson correlation coefficient for hemoglobin was highest with mean corpuscular volume, erythrocyte protoporphyrin, serum iron, transferrin saturation, total-iron-binding capacity, and serum ferritin. Mean corpuscular hemoglobin and transferrin saturation were abnormal in greater than 90% of anemic children, whereas serum ferritin and total-iron-binding capacity were abnormal in only 70%. In view of its limited sensitivity, serum ferritin appears to be a less useful diagnostic aid in iron-deficiency anemia than other, less expensive laboratory methods.

Anemia, Hypochromic↗
PubMed1979

Suppressive effect of ferritin on in vitro lymphocyte function.

This study describes the effect of ferritin on lymphocyte function in vitro. Peripheral blood lymphocytes isolated from normal donors were incubated with purified human splenic ferritin, and the mitogenic effect of phytohaemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM) and mixed lymphocyte reaction (MLR) were assessed by the uptake of 3H-thymidine (3H-TdR). Ferritin (0.25--5.0 micrograms/ml culture) caused a marked suppression of PHA nad Con A blastogenesis but had no suppressive effect on PWM-induced transformation. Maximal suppression was obtained at a ferritin concentration of 1 microgram/ml and this was not enhanced by increasing ferritin concentrations. Ferritin also reduced the Con A capping phenomenon in normal lymphocytes from 22% to 6%, suppressed the MLR reaction but had no effect on the ability of normal lymphocytes to form E, EA and EAC rosettes or on in vitro lymphocyte cytoxicity against the K-562 cell line. Visual proof of the suppressive effect of ferritin on mitogen induced blastogenesis was provided by scanning electron microscopy, and direct evidence for the ability of lymphocytes to bind ferritin was obtained from studies with radioiodine labelled ferritin. The above findings indicate that ferritin suppresses certain parameters of T-lymphocyte function in vitro. The relation of the present findings to recognized abnormalities of T-cell function encountered in certain neoplastic disorders associated with high serum ferritin levels is at present unknown.

Cytotoxicity, Immunologic↗
PubMed1979

Prevalence and causes of anemia in elderly hospitalized patients.

The prevalence and causes of anemia have been studied in 104 patients over 60 years of age admitted to a general medical ward in Jerusalem. In males and females, mean hemoglobin levels were about 1 g less than in the corresponding groups of healthy younger controls. A primary nutritional anemia could not be implicated in any of the 15 patients with hemoglobins below 11 g/dl. The most important causes of anemia were chronic renal failure, metastatic carcinoma, gastrointestinal bleeding, and infection. Conversely, in diseases with no adverse effect on erythropoiesis such as chronic ischemic heart disease, hypertension and diabetes, hemoglobin levels were equal to those of the younger controls. These findings indicate that although diminished serum iron and RBC folate levels may occasionally be found in elderly subjects, nutritional deficiency is seldom responsible for anemia in this age group in Israel- and anemia when present is often the manifestation of a chronic underlying disease.

Adult↗
PubMed1978

Granulocyte transfusion therapy: a clinical trial in patients with acute leukemia and sepsis.

The effect of granulocyte transfusions on the course of infection in patients under treatment for acute leukemia was evaluated by comparing 19 febrile episodes in 15 patients receiving antibiotics alone with 18 febrile episodes in 13 patients receiving antibiotics in combination with granulocyte transfusions from ABO-matched donors. Both groups had a similar age, sex distribution and duration of disease prior to the febrile episode. About two-thirds of the patients in both groups had acute myeloblastic leukemia. 94% of the patients in the transfused group and 74% of the control group survived the febrile episode. In patients with positive blood cultures all transfused patients survived as compared to only 57% in the control group (p=0.05). In patients with persistent bone marrow failure 92% of the transfused patients survived as compared to 73% in the control group. Granulocyte transfusions had no effect on the outcome of febrile episodes in patients with negative blood cultures or early recovery of marrow function. These data appear to support the contention that granulocyte transfusions are beneficial in patients with blood culture-proved sepsis with persistent neutropenia.

Adult↗
PubMed1978

Ethnical and clinical aspects of chronic lymphocytic leukemia in Israel: a survey on 288 patients.

The ethnic distribution of 288 patients with chronic lymphocytic leukemia (CLL) from five medical centers in Israel during the decade 1960--1970 was investigated as well as other features of the disease. 80.5% of the patients were of East European descent, 14.5% originated from Asia and Africa and 5% were born in Israel. Based on the ethnic distribution of the elderly population of Israel during the above period, it is suggested that CLL occurs more frequently in European-born Jews than in Asian and African Jews. A low occurrence of Coombs positive hemolytic anemia was revealed, amounting to 7.2% of the patients. Of 68 patients who underwent serum immunoglobulin studies, up to 74% exhibited deficiency of at least one type of immunoglobulin. Low levels of IgA were encountered in 61.2%, IgM in 51.5% and IgG in 29.5% of the patients. 26 of 206 patients with CLL (12.5%), all of East European origin, had an additional primary malignant tumor, cancer of the skin and breast being the most frequent associated malignancies. In 6 patients of the 26, two additional neoplasms were diagnosed. Hypogammaglobulinemia was more frequent in patients with additional primary malignant tumors and in patients with advanced disease. The possible causes for the ethnic distribution of CLL in Israil as well as of other tumors are discussed.

Africa↗
PubMed1978

Natural killer activity in patients with acute myelocytic leukemia.

The natural killer activity of isolated mononuclear cell populations of acute myelocytic leukemia (AML) patients in remission and relapse was compared with that of mononuclear cells obtained from normal subjects. The target cells consisted of 51Cr-labeled blast cells of the K-562 cell line, which was originally obtained from a patient with chronic myelocytic leukemia in blast crisis. The natural killer activity of lymphocytes from AML patients in remission was similar to or higher than that of normal subjects. A marked depression in this function was associated with relapse, as well as with heavy combined chemotherapy. It is concluded that natural killer activity assessed in vitro is an accurate indicator of the clinical stage of AML patients.

Adult↗
PubMed1978

Hodgkin's disease.

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Bacterial Infections↗