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Biomedical subjects

Y Barak

Publications and source records attributed to Y Barak.

At least 181 records · Page 10Linked to original sources
PubMed1985

Brain: body ratio and conceptional age in vascular-induced intrauterine growth retarded rabbits.

Vascular induced intrauterine growth retardation (IUGR) was achieved by total ligation of approximately 30% of the placental vessels to half the fetuses in the last third of gestation in pregnant rabbits. A correlation between brain weight, body weight and head circumference was established in fetuses and rabbit pups in the perinatal period. The brain:body ratio in restricted IUGR animals was significantly higher than their homologous normal controls. A cephalization index based on the brain:body ratio is proposed to assess adverse effects on brain maturity in the presence of IUGR induced by placental insufficiency.

Animals↗
PubMed1985

The cephalization index: a screening device for brain maturity and vulnerability in normal and intrauterine growth retarded newborns.

Predictive estimates of future neurological maldevelopment as a result of vascular induced intrauterine injury are based on the assumption that the body is more affected than the brain resulting in asymmetrical intrauterine growth retarded (IUGR) newborns. The higher the brain:body ratio, the more severe the IUGR process and the greater the risk for the brain to be affected. This prompted us to study in human newborns, a cephalization index based on the ratio of head circumference to body weight to express the degree of brain maturity and possible vulnerability in relation to gestational age. The newborn cephalization index was correlated with neurodevelopment. A trend could be delineated; in the later gestational age, the higher the cephalization index reflecting a greater degree of brain vulnerability, the more severe the clinical pathology; especially the likelihood of cerebral palsy and severe psychomotor retardation. The cephalization index may serve as an additional screening device for high risk intrauterine growth retarded newborns.

Body Weight↗
PubMed1985

Noma in a full-term neonate.

Noma is an uncommon gangrenous process usually affecting malnourished children. A full-term neonate with orofacial noma, bilateral choanal atresia, and transient neutropenia with B cell deficiency is reported. This unusual appearance of noma in a well-nourished newborn might be related to the combination of choanal atresia and transient immune deficiency.

Agranulocytosis↗
PubMed1985

Lymphoid cells and granulocyte progenitors in early human fetal livers: immunological parameters and in vitro cellular interactions.

Human fetal liver (HFL) transplantations have been performed in infants with severe combined immunodeficiency and in patients with aplastic anemia, but the success rates have been extremely low, partly due to insufficient cell doses in grafts from a single donor. In order to explore the possible use of combining several HFL grafts from multiple donors, we studied immunological parameters as well as the in vitro responses of HFL cells from 20 fetuses, at 6 to 11 weeks of gestation, to allogeneic HFL cells and to adult lymphocytes in the mixed lymphocyte reaction (MLR), and the granulocyte-macrophage colony-forming cells (GM-CFC) assay. HFL cells of 6 to 11 weeks of gestation were found to lack populations of cells bearing surface markers of T- and B-lymphocytes and were capable of proliferating into lymphoid colonies. Virtually no MLR was found to allogeneic HFL cells or to adult lymphocytes [stimulation index (SI) 0.63 to 1.94], whereas adult lymphocytes responded normally to HFL cells (SI 3.9 to 62.0). Coculturing mixtures of allogeneic HFL cells in agar did not lead to suppression of the GM-CFC capacity of each liver. It appears that HFL at 6 to 11 weeks of gestation lack immunocompetent cells capable of provoking positive MLR in response to allogeneic HFL cells or to adult lymphocytes, and also capable of inactivating HFL-derived hematopoietic stem cells. This model may represent an in vitro counterpart for the in vivo pooling of HFL cells from multiple donors performed in order to increase graft cell dosage in man.

Adult↗
PubMed1983

Migration of human leukocytes from soft agarose droplet: a simplified method for studying chemotaxis and spontaneous migration.

Studies of in vitro chemotaxis and spontaneous migration of human leukocytes using the accepted method with the Boyden-chamber-filter are troublesome, because of the need for specially constructed vessels as well as the difficulties caused by the use of membrane filters. We describe a new and simplified method for measuring human leucocyte chemotaxis, which is a modification of the recently described underagarose migration method and which is based upon spontaneous migration of cells from a soft agarose droplet and in response to a chemotactic gradient. We examined suspensions of leukocytes, purified granulocytes, and mononuclear cells from 10 healthy normal adults and from 10 samples of cord blood using E Coli O111B4 endotoxin-activated human serum as attractant. Our results showed that the mean chemotactic indices (C.I.-chemotaxis/migration) for purified granulocytes and for mononuclear cells from normal individuals were 3.0 +/- 1.2 and 2.7 +/- 1.5, respectively. Chemotaxis was significantly reduced when unwashed leukocytes were studied, indicating a detrimental effect of autologous plasma on leukocytic response to a chemotactic stimulus in this system. Cord blood cells showed normal spontaneous migration, but significantly decreased chemotaxis. This preliminary report shows that the technique is simple, rapid, and reproducible, and can detect abnormalities of chemotaxis in both granulocytes and mononuclear cells.

Adult↗
PubMed1983

Organophosphate poisoning presenting as diabetic ketoacidosis.

A 3-year-old boy was admitted to hospital following rapid-onset coma. Laboratory tests demonstrated hyperglycemia, glycosuria and keto-acidosis. Organophosphorus poisoning was the cause of the coma since he had been in contact with Parathion, serum cholinesterase activity was undetectable and his condition returned to normal under atropine therapy.

Acidosis↗
PubMed1982

Hairy cell leukemia: defective production of granulocyte-macrophage colony-stimulating factor by peripheral blood cells.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) production by the peripheral blood (PB) cells of hairy cell leukemia (HCL) patients whose PB contained only 2 to 10% hairy cells was studied in an in vitro bone marrow culture system. In addition, the possible inhibitory effect on the growth of normal granulocyte-macrophage colony-forming cells (GM-CFC) by the patients' mononuclear cells or serum was assayed. GM-CSF production by PB cells of HCL patients was 82 +/- 18% (mean +/- sd) lower than its production by normal PB cells. No significant inhibition of normal GM-CFC growth was observed in the presence of patients' PB mononuclear cells or their serum. These findings suggest that in HCL patients the monocyte-macrophage system is defective in its capacity to produce GM-CSF. This defect may play a role in the impaired granulocyte production known to occur in HCL.

Adult↗
PubMed1982

Contamination of human placental granulocyte macrophage colony stimulating factor by bacterial endotoxin: its removal by a simple adsorption technique.

Bacterial endotoxin was detected by the Limulus Amebocyte Lysate (LAL) assay in four preparations of human placental granulocyte-macrophage colony-stimulating-factor (HP-CSF), a humoral factor required for the production of human granulocyte-macrophage colonies in semi-solid cultures. The complete removal of endotoxin from these preparations was carried out by its adsorption to LAL proteins, either directly of following coupling to sepharose beads. Removal of endotoxin from HP-CSF did not result in any reduction of its in vitro granulopoietic activity, and the LAL-sepharose complex could be recycled for further use.

Adsorption↗
PubMed1981

Juvenile and adult types of chronic granulocytic leukemia of childhood: growth patterns and characteristics of granulocyte-macrophage colony forming cells.

Peripheral blood and bone marrow cells from three children with the juvenile (Ph1 negative) type of chronic granulocytic leukemia and from one with the adult (Ph1 positive) type were cultured in soft agar, and their specific growth patterns were evaluated. Greatly increased numbers of colonies were obtained in all cases, particularly from peripheral blood cells. By morphologic, cytochemical and ultrastructural criteria, colonies from one juvenile type and from the single adult type patients were found to be almost exclusively granulocytic, whereas in the other two juvenile type leukemia patients colonies were either granulocytic or macrophage. Moreover, both growth patterns were obtained in the same patients on different occasions. It appears that the leukemic cell populations of the juvenile and the adult forms of chronic granulocytic leukemia do not arise from different cell lines. Rather, both are the progeny of the common monocyte-granulocyte progenitor cell, whose abnormal proliferation and differentiation along either the granulocytic or the monocytic pathway is probably directed by fluctuations in humoral and/or microenvironmental factors.

Bone Marrow↗
PubMed1981

The genetics of the aryl sulfatase A locus.

A genetic analysis was performed in an isolate in which metachromatic leukodystrophy (MLD) and aryl sulfatase A (ASA) pseudodeficiency are relatively frequent. The frequency of matings at risk and the frequency of ASA pseudodeficiency among parents of MLD patients are compatible with allelism between the gene determining MLD and the gene determining ASA pseudodeficiency. Two independent pedigrees including MLD patients and ASA-deficient healthy individuals also fit the model of allelism.

Alleles↗
PubMed1980

Neonatal neutrophilia: possible role of a humoral granulopoietic factor.

During the first days of life, newborn infants have leucocytosis with marked neutrophilia and a "shift to the left," the mechanism for which is as yet unknown. In an attempt to elucidate whether humoral granulopoietic factor(s) plays a role in this phenomenon, serial measurements of urinary and serum colony-stimulating activity levels were made in healthy newborn infants and normal older controls. Twenty-four-hr urine collections, serum samples, and complete blood counts were obtained from 30 full-term normal infants 24 hr and 4 days after delivery and in 13 of them on the 14th and 28th days of life as well. Specimens were assayed for their colony stimulating activity levels by their ability to stimulate bone marrow cells from C3HB mice to grow into colonies in soft agar. Elevated neutrophil, band form, and monocyte counts were found during the first day of life, which gradually decreased thereafter. Serum and urinary colony-stimulating activity levels were significantly increased (3- to 5-fold) over the controls on the first and fourth days of life, but declined to normal values by the 14th and 28th days.

Age Factors↗
PubMed1980

Granulocyte-macrophage colonies in cultures of human fetal liver cells: morphologic and ultrastructural analysis of proliferation and differentiation.

Fetal liver cells from 6-12-week-old human fetuses were cultured in soft agar to study growth patterns of the granulocyte-macrophage colony forming cells (CFU(c)) and to characterize the cellular components of these colonies by morphologic, cytochemical and ultrastructural methods. Liver cell suspensions prepared from 31 fetuses obtained by vaginal interruptions of pregnancies, were seeded in soft agar over feeder layers of normal human leukocytes. At all gestational ages examined, agar colony numbers ranged from 44 +/- 15 to 89 +/- 44/2 x 10(5) cells seeded. Colony frequencies, size and gross morphology closely resembled those derived from adult human marrow. Morphologic, cytochemical and ultrastructural examinations showed that 92% of the colonies were granulocytic with incomplete maturation, as found in adult human marrow colonies. Density fractionation of the cells produced a low density cellular fraction which gave a 3- to 5-fold improved cloning efficiency. This study shows that human fetal livers of 6-12 weeks gestational age contain CFU(c) comparable to that found in adult marrow in their frequency, size, density and dependence on colony stimulating factor, and which differentiate mainly into mature or immature granulocytes. It is suggested that the lack of granulopoiesis in vivo in the early human fetal liver is probably not related to CFU(c) deficiency or defective differentiation. An alternative explanation involving impaired regulatory mechanism(s) should be sought.

Cell Differentiation↗
PubMed1980

Metachromatic leukodystrophy in the habbanite Jews: high frequency in a genetic isolate and screening for heterozygotes.

A very high incidence of late infantile metachromatic leukodystrophy (MLD) (1/75 live births) was found in the Jewish Habbanite community which constitutes a genetic isolate of about 1,000-1,200 individuals. Screening in this population for aryl sulfatase A (ASA) levels in married adults revealed a carrier frequency for MLD of 17% and identified six couples of whom both partners were heterozygotes (6% of screened couples). In three pregnancies of these couples, prenatal diagnosis for the detection of ASA in the fetus was performed.

Adult↗
PubMed1979

Response of neonatal hypocalcaemia to 1 alpha-hydroxyvitamin D3.

Administration of 1 alpha-OH-D3 to hypocalcaemic neonates (mean +/- SD, serum calcium 1.50 +/- 0.13 mmol/l) significantly increased serum calcium in all 24 infants within 48 hours after starting therapy (mean +/- SD 1.83 +/- 0.23 mmol/1). The time required to correct hypocalcaemia was significantly shorter (2.04 +/- 0.56 days) in infants treated with 1 alpha-OH-D3, than in 24 infants treated with calcium gluconate infusions (4.12 +/- 1.0 days). Treatment with 1 alpha-OH-D3 was effective, easy to maintain, and produced no side effects.

Calcium Gluconate↗