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Biomedical subjects

C W Daeschner

Publications and source records attributed to C W Daeschner.

At least 19 recordsLinked to original sources
PubMed1992

Benefits of a lower hematocrit during extracorporeal membrane oxygenation?

OBJECTIVE: To determine the possible benefits of maintaining a lower hematocrit than that normally used (0.35 vs 0.45) in neonates treated with extracorporeal membrane oxygenation. DESIGN: Randomized cohort. SETTING: Neonatal and pediatric intensive care units at a university hospital. PARTICIPANTS: Twenty neonates who met criteria for receiving extracorporeal membrane oxygenation from May 1988 to March 1990. INTERVENTIONS: Hematocrits were maintained at 0.35 for neonates in group 1 and 0.45 for neonates in group 2. MEASUREMENTS/MAIN RESULTS: Hematocrits were measured every 4 hours. Visible clots in the major circuit components were recorded. Infants in group 1 received (mean +/- SD) 2.5 +/- 0.6 mL of packed red blood cells per hour of extracorporeal membrane oxygenation while infants in group 2 received 3.8 +/- 0.9 mL of packed red blood cells per hour of extracorporeal membrane oxygenation. In group 1, clots were noted in six of 10 oxygenators and five of 10 bladder reservoirs. In group 2, clots were found in all 10 oxygenators and bladder reservoirs. CONCLUSIONS: Neonates' hematocrits can be maintained safely at 0.35 during extracorporeal membrane oxygenation with significantly less exposure to packed red blood cells and less clotting in the circuit.

Blood Coagulation↗
PubMed1992

Fine needle aspiration biopsy cytology as an adjunct in the diagnosis of childhood sarcoidosis.

Fine needle aspiration biopsy cytology performed in three children with sarcoidosis expedited clinical investigation and diagnosis of their disease. Each patient had a different clinical presentation; in two of them lymphoma was part of the initial differential diagnosis. Aspiration cytology in all cases revealed collections of epithelioid histiocytes, and multinucleate foreign body-type giant cells, without accompanying necrosis or acute inflammation. A diagnosis of non-caseating granulomas consistent with sarcoidosis was made in all aspirates. Special stains for identification of organisms performed on the smears of one case, and culture of aspirate material from one case were negative. Subsequent serum angiotensin converting enzyme levels in all patients were elevated. Chest x-ray films in all patients showed mediastinal and hilar lymphadenopathy. One patient had an interstitial pulmonary infiltrate. All patients responded to steroid therapy. Fine needle aspiration biopsy can be a useful diagnostic tool in the evaluation of children with suspected sarcoidosis.

Adolescent↗
PubMed1991

Suppression of graft-versus-host reaction in severe combined immunodeficiency with maternal-fetal T cell engraftment.

Simultaneous engraftment of maternal T cells and T cells from unrelated transfusion donor in an infant with severe combined immunodeficiency disease (SCID) was identified by HLA typing blood lymphocytes of the patient, her triplet siblings, parents, and the platelet donor from whom the patient received nonirradiated platelet transfusion. T cell grafts from both the mother and platelet donor were stable for several months, but the graft-versus-host reactions (GvHR) remained mild and immune function was deficient. We hypothesize that immunosuppressive effects of a maternal-fetal GvHR may have modified the expected lethal GvHR from platelet donor's T cells.

Agammaglobulinemia↗
PubMed1990

Decreasing blood donor exposure in neonates on extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) has been successful treatment (80% survival) in over 2,000 neonates with severe respiratory failure (80% predicted mortality without ECMO). Neonates on ECMO require frequent blood product replacement, which increases donor exposure (DE) and the risk of transfusion related complications. Successful, widespread usage of ECMO in neonatal respiratory failure is placing increased numbers of surviving infants at risk for acute and long-term transfusion related problems. We assessed DE rates in 21 consecutive neonatal ECMO survivors. In the first 12 patients packed red blood cell (PRBC) transfusions were administered as 10 mL/kg body weight for hematocrit less than 45%. PRBC exchange transfusions were used in patients with hematocrit less than 45% and hypervolemia. Fresh frozen plasma (FFP) and cryoprecipitate (CRYO) infusions were used empirically for evidence of hemorrhage. DE rates (donors per ECMO day, mean +/- SD) were: PRBC (2.8 +/- 0.6), FFP/CRYO (0.5 +/- 0.7), and platelet (2.0 +/- 1.0), with a total donor exposure rate of 5.3 +/- 2.0 donors per ECMO day. Mean duration of ECMO was 4.6 +/- 2.0 days and total DE per infant was 22.8 +/- 9.5 donors per ECMO run. In a protocol (n = 9) to minimize DE risks, exchange transfusions were eliminated and PRBC transfusion volumes were increased to 15 mL/kg. Empiric use of FFP and CRYO was discontinued. The blood bank divided standard units of PRBCs into four aliquots and dispensed each aliquot sequentially before dispensing blood from another unit.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Donors↗
PubMed1988

Effects of iron, copper, zinc, calcium, and magnesium on human lymphocytes in culture.

The effects of simultaneous changes of calcium, magnesium, iron, copper, and zinc concentrations were evaluated in normal human T and B lymphocytes, cultured in cation-depleted media. Optimal concentrations for thymidine incorporation (TI) in both cell populations were Fe and Zn 15 microM and Cu 5 microM; for T cells Ca 2 mM and Mg 4 mM; for B cells Ca 4 mM and Mg 6 mM. TI decreased with increasing molarity of cations and the decrease was particularly apparent with Cu. Minimal amounts of Ca and Mg (0.5 mM) were necessary for growth, even in presence of optimal concentrations of Fe, Cu, and Zn. Fe and Cu showed synergistic stimulatory effects at low concentrations and synergistic inhibitory effects at high concentrations. Antagonism between Fe and Zn, Cu and Zn, and Ca and Zn was also demonstrated. CD4/CD8 increased with PHA stimulation in presence of Zn, and decreased with ConA stimulation in presence of Zn or Fe. The results demonstrate: (1) the relationship and interdependence of Fe, Cu, and Zn concentrations in modulating the growth of normal lymphocytes; (2) the stimulatory effects of Fe on B cells and Zn on CD8 positive cells; (3) the inhibitory effect of Cu at concentrations lower than those of Fe and Zn; (4) the requirement of Ca and Mg in certain concentration and ratio for the action of the other cations; and (5) the Ca and Mg requirement for the growth of B cells higher than T cells.

B-Lymphocytes↗
PubMed1987

Observations on the use of a cation exchange resin for the preparation of metal-depleted media for lymphocyte culture.

A chelating resin specific for divalent cations (Chelex) was used to prepare metal-depleted media for lymphocyte culture. A batch procedure (resin in pH 7.4 phosphate buffer/specimen, 1:1) removed 70-80% of iron, 77-87% of copper and 88-98% of zinc, calcium and magnesium. At variance with other reports, when a resin/specimen ratio of 1:4 was used, iron chelation decreased to 40%, whereas other cation chelation remained unchanged. Best chelation for iron and calcium was obtained at pH 5-6.4; for copper, zinc and magnesium, at pH 7.4-8.0. During the procedure protein content decreased by 8-10%; arginine and lysine by 80%; asparagine, cystine, tyrosine and phenylalanine by 60%, other amino acids by 35%. These new data suggest that cation-depleted media prepared with Chelex may be used to study the effects of cations on lymphocytes in culture, provided that the most appropriate pH and resin/specimen ratio are selected and adequate amino acid replacement is performed. Results on normal human lymphocytes are reported.

Cation Exchange Resins↗
PubMed1986

Copper, zinc, and iron in normal and leukemic lymphocytes from children.

Copper, zinc, and iron were quantitated in the serum and lymphoid cells of the peripheral blood of healthy children and children with acute lymphocytic leukemia. Copper and iron concentrations in serum and cells were significantly higher and zinc concentration in the cells significantly lower in leukemic patients than in healthy donors, whereas the increase of zinc in the serum was not significant. The concentration of all minerals was higher in T-cell enriched preparations. There was a significant correlation between copper and iron and between copper and zinc, but not between iron and zinc in normal and leukemic lymphocytes. No correlation was demonstrated among the three minerals in the serum. There were no significant differences associated with ethnicity, age, sex, type of leukemia, or number of leukemic cells. However, a group of five children with non-B-, non-T-cell acute lymphocytic leukemia, nonreactive skin tests, and low serum immunoglobulins had high concentrations of copper and iron and low concentration of zinc in their leukemic cells. Since copper, zinc, and iron are associated with lymphocyte maturation and regulation of immune function, these new data will provide a tool for the study of the relationship between changes in concentrations of these metals and the modification of the immune response often present in hematologic cancers.

Child↗
PubMed1985

Zinc deficiency and blood lymphocyte function with sickle cell disease.

A relationship between zinc deficiency and lymphocyte function in children with sickle cell disease (SCD) has been suggested. Number and function of B and T lymphocytes were assessed in 3 matched groups of children: normal subjects with Hb A and normal zinc; patients with SCD; and normal zinc (SCD-N); and patients with SCD and decreased zinc (SCD-D). Percentages of B and T cells, response to cutaneous antigens and increases in tetanus antibody titres were similar among all groups. Absolute numbers of WBC, lymphocytes and B and T cells were markedly increased in SCD-N (p less than 0.001) and to a lesser degree in SCD-D (p less than 0.01). Controls and SCD-N had a normal response to all mitogens, which was not inhibited by SCD-D sera. SCD-D had a depressed response to PHA (p less than 0.001), which was not corrected by zinc addition in vitro. These findings indicate that B cell function and T cell-dependent delayed hypersensitivity are normal in children with SCD and are independent of body zinc status. They also suggest some abnormality of T helper cells in the presence of zinc deficiency, and in the absence of a demonstrable serum inhibitor.

Adolescent↗
PubMed1985

Glucose-6-phosphate dehydrogenase Beaumont: a new variant with severe enzyme deficiency and chronic nonspherocytic hemolytic anemia.

Studies were carried out on erythrocytes and fibroblasts from a 3-year-old white male with severe glucose-6-phosphate dehydrogenase (G6PD) deficiency and chronic non-spherocytic hemolytic anemia. Red blood cell G6PD activity was less than 0.02% of normal values. Since the child's fibroblasts had 2-4% of normal enzymic activity, they were utilized as a source of enzyme for kinetic studies. The G6PD demonstrated marked heat lability, a normal Km value for glucose-6-phosphate (56 mumol/l), a nearly normal pH-activity curve, and increased utilization of 2-deoxyglucose-6-phosphate (76% of the rate with glucose-6-phosphate). These studies clearly indicate that this is a new molecular variant (G6PD Beaumont).

Adult↗
PubMed1976

A method for defining competency in Pediatrics.

In 1972 the American Board of Pediatrics (ABP) initiated studies leading to a report which identifies the important components of competency needed in the practice of pediatrics. The development of the report involved a group process engaging ABP board members and examiners. The outcome has been (a) the delineation of a process for establishing definitions of competency in a medical discipline; (b) the development of a framework for specifying the abilities needed to perform the tasks required of pediatricians; (c) an elaboration of samples of pediatric subjects to which these abilities and tasks are relevant; and (d) the development of a basis for choice of methods to use for purposes of certification.

Certification↗