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Biomedical subjects

M Gahr

Publications and source records attributed to M Gahr.

At least 109 records · Page 6Linked to original sources
PubMed1987

A boy with recurrent infections, impaired PMN-chemotaxis, increased IgE concentrations and cranial synostosis--a variant of the hyper-IgE syndrome?

A patient with coarse facies, craniosynostosis, recurrent staphylococcal infections with pneumatocele formation is described. Laboratory features included moderately elevated serum IgE, cutaneous anergy, decreased numbers of T-suppressor cells and variable inhibition of neutrophil chemotaxis. The combination of clinical findings suggests the diagnosis hyper-IgE syndrome, though the total IgE serum concentration (800 U/ml) and the level of IgE-specific antibodies to staphylococci (9.4%, normal less than 5%) were only slightly elevated.

Chemotaxis, Leukocyte↗
PubMed1986

Clinical symptoms and biochemical properties of three new glucosephosphate isomerase variants.

Glucosephosphate isomerase deficiency as the cause of macrocytic congenital nonspherocytic hemolytic anemia is described in three unrelated families. The biochemical properties of the variant glucosephosphate isomerases indicate that the patients have new variants, designated as GPI Kiel, GPI Hamburg, and GPI Homburg. The severity of the clinical symptoms depended on the amount of residual GPI activity and the biochemical properties of the variant enzyme. Thus the patient with GPI Kiel (34% residual activity) whose variant GPI was slightly unstable showed a mild chronic hemolytic anemia. The patient with GPI Homburg (7% residual activity) whose variant enzyme was stable and had a reduced specific activity, suffered from severe congenital hemolytic anemia and neuromuscular symptoms. Due to the special properties of GPI Homburg, we assume that both the hematological and neuromuscular symptoms of the patient with GPI Homburg are caused by his GPI deficiency. The twins with GPI Hamburg (27% residual activity) had a distinctly unstable variant enzyme and had suffered from hemolytic crises since birth. Only GPI Homburg showed an altered electrophoretic mobility and an increased affinity for fructose-6-phosphate. The other two variants had normal values.

Adolescent↗
PubMed1986

Phagocytic activities in neonatal monocytes.

Monocytes play an essential role in cellular host defense as circulating phagocytes, as well as precursors of macrophages. We investigated the principal phagocytic activities in monocytes from cord blood of term infants by analysing adherence, random migration, chemotaxis, bactericidal activity, phagocytosis-associated chemiluminescence, production of superoxide anion (O-2) and generation of hydrogen peroxide (H2O2). All phagocytic functions of monocytes from neonates were shown quantitatively to be comparable to those of cells from healthy adult volunteers. The increased susceptibility of the human neonate to serious systemic infections cannot be related to an abnormality in monocyte function.

Adhesiveness↗
PubMed1986

Effect of age on homovanillic and 4-hydroxy-3-methoxymandelic acid levels in plasma.

The plasma levels of homovanillic and 4-hydroxy-3-methoxymandelic acids have been determined in 524 normal subjects ranging from birth to 49 years of age using a mass fragmentographic method. The mean concentration of homovanillic acid in plasma declines exponentially from the age of 1 day (X = 2342.0 nmol/l, 426.6 ng/ml) to adulthood (X = 60 nmol/l, 10.9 ng/ml). 4-Hydroxy-3-methoxymandelic acid behaves in a similar although not so extreme manner (392 nmol/l, 77.6 ng/ml-50 nmol/l, 10 ng/ml).

Adolescent↗
PubMed1986

Phagocytosis-associated oxidative metabolism in human milk macrophages.

Evidence exists that human milk macrophages, which are the most abundant cells in milk, play an important role in the protection of the newborn infant against infection. We investigated the oxidative metabolism of milk macrophages by measuring luminol-dependent chemiluminescence, generation of superoxide anion (O2-) and production of hydrogen peroxide (H2O2) in the resting state and after stimulation with opsonized zymosan or phorbol myristate acetate (PMA). Generally, macrophages generated luminol-dependent luminescence, O2- and H2O2 with either stimulus to a similar extent as did blood monocytes. In addition, macrophages killed Escherichia coli and Staphylococcus aureus as effectively as did blood monocytes (approximately 75%, 120 min). Acidification of macrophages in milk (pH 1, 30 min) only slightly reduced their PMA-stimulated production of oxygen radicals. Bacterial killing by macrophages preincubated at pH 1 was about 70% that from controls maintained at pH 7. When macrophages were cultured for several days in endotoxin-free medium, their ability to produce oxygen metabolites declined. By continuous treatment with bacterial LPS (10 ng/ml), milk-macrophages could be "primed" to release large amounts of oxygen intermediates. In addition, the O2- response of macrophages cultured without bacterial products could be partially restored by the addition of LPS to the culture. We conclude that milk macrophages are capable of releasing large amounts of oxygen metabolites, and could contribute to the protection of neonates against bacterial and fungal infections.

Cells, Cultured↗
PubMed1986

[Infection and neonatal meningitis: epidemiology, pathogen spectrum, therapy].

Data from 196 infants were analyzed who had been treated for neonatal septicemia and/or meningitis between 1962-1974 (n = 88) and 1975-1985 (n = 108). In addition to an increase in the incidence of septicemia (1962-1974: 0.88 cases/1000 live births/year; 1975-1985: 1.8 cases/1000 live births/year) there was also a change in the pattern of infection. Group B streptococcal infections were first observed in 1975. Infections with Escherichia coli increased (1962-1974: 0.25 cases/1000 live births/year; 1975-1985: 0.65 cases/1000 live births/year). Although the incidence of meningitis was similar in both periods (1962-1985: 0.45 cases/1000 live births/year) the relative number of cases declined (1962-1974: 51 of 88 patients; 1975-1985 25 of 108). Mortality also decreased during the second period (1962-1974: 53%; 1975-1985: 29%). All infants were primarily treated with a combination of ampicillin and gentamicin. The decision to discontinue this therapy was based on the clinical course of the patient and the results of culture and susceptibility studies. Ampicillin and/or gentamicin were effective in vitro against all microorganisms which caused septicemia and/or meningitis within the first four days of life. In contrast this antimicrobial combination was only active in vitro against 77% of the pathogens isolated after this time period.

Anti-Bacterial Agents↗
PubMed1985

Glucose-6-phosphate dehydrogenase (G6PD) Iserlohn and G6PD Regensburg: two new severe enzyme defects in German families.

Two new inheritable variants of glucose-6-phosphate dehydrogenase have been found in two unrelated German families. Patients with one variant (G6PD Iserlohn, also referred to as G6PD I) suffered from intermittent hemolytic crises caused by fava beans; patients with the other variant (G6PD Regensburg, G6PD II) disclosed chronic nonspherocytic hemolytic anemia aggravated by drug treatment. Due to their unusual biochemical characteristics, the new variants were designated G6PD Iserlohn and G6PD Regensburg. Both variants showed a reduction of enzyme activity to about 6% of the normal in erythrocytes, normal electrophoretic mobility, increased affinity for glucose-6-phosphate, a reduced affinity for NADP and a pH optimum in the neutral region (7.0 and 7.5). G6PD Iserlohn had a decreased affinity for the inhibitor NADPH; G6PD Regensburg had a normal inhibitor constant. Deamino NADP was utilized at an increased rate by G6PD Regensburg. G6PD Iserlohn was thermostable, G6PD Regensburg mildly instable. G6PD activity in leukocytes was normal in G6PD Iserlohn and reduced to the same degree as in erythrocytets in G6PD Regensburg. The cause of the decreased activity of G6PD Iserlohn appears to be in vivo instability; in G6PD Regensburg further mechanisms might include reduced specific activity or reduced synthesis of the variant enzyme.

Anemia, Hemolytic↗
PubMed1985

Generalised glucosephosphate isomerase (GPI) deficiency causing haemolytic anaemia, neuromuscular symptoms and impairment of granulocytic function: a new syndrome due to a new stable GPI variant with diminished specific activity (GPI Homburg).

A new glucosephosphate isomerase (GPI) variant is described which is characterised by very low specific activity in erythrocytes, granulocytes and muscle tissue, nearly normal stability, normal kinetic properties and a decreased electrophoretic mobility. The propositus suffers from a complex syndrome involving erythrocytes (congenital haemolytic anaemia), granulocytes (decreased production of superoxide anion and reduced bactericidal activity in vitro) and the neuromuscular system (myopathy, mental retardation). It is suggested that the clinical syndrome results from generalised GPI deficiency due to a decreased specific activity of the variant enzyme, which cannot be compensated by an increase of de-novo synthesis of GPI protein even in cells exhibiting active protein synthesis such as granulocytes and muscle cells.

Adolescent↗
PubMed1985

Polymorphonuclear leukocyte function in term and preterm newborn infants.

Bacterial infections are a major problem in the care for newborn infants. In search for immunological deficits we investigated phagocytosis and killing of staphylococci using polymorphonuclear leukocytes (PMN) isolated from 2 ml of venous blood. Phagocytosis of PMN from preterm (n = 10) and newborn infants (n = 9; mean birth weights 1,949 and 3,523 g, respectively) was not different from that of adult PMN (n = 14). Killing capacity of PMN from preterm infants was markedly impaired compared to term newborn infants and to adult PMN. We found similar rates of superoxide anion production and similar times for activation in response to phorbolmyristate acetate stimulation. Our study gives further evidence that PMN from term newborn infants have normal phagocytotic and bactericidal capacity. In PMN from preterm newborn infants, however, the bactericidal capacity is diminished similar to newborn infants under stress as described earlier by others.

Adult↗
PubMed1985

[Function of breast milk macrophages].

Human milk is a suspension of viable cells. Macrophages are the most abundant cells, comprising 40-80% of the total cell count. The present study was initiated to examine the principal cell functions of phagocytic milk macrophages: adherence, chemotaxis and phagocytosis-associated bactericidal oxidative metabolism. Adherence of milk macrophages to nylon wool was significantly decreased when compared with blood monocytes. In addition chemotaxis of macrophages in response to C 5a or a synthetic chemotactic peptide was also decreased. However, macrophages produced oxygen intermediates (O2-), H2O2) to a similar extent as blood monocytes after stimulation of the "oxidative burst" with phorbol myristate acetate or opsonized Candida particles. Macrophages cultured in vitro in endotoxin-free medium without serum lost the ability to produce oxygen metabolites over the course of a few days. Partial restoration of the oxygen radical production could be detected in macrophages exposed to bacterial lipopolysaccharide, i.e. endotoxin (LPS, 10 ng/ml). Endotoxin, which is present in the gut even of newborns might provide enough stimulation to maintain macrophages in the "primed" state. We conclude that oxygen metabolites released from milk macrophages are highly reactive and could contribute essentially to the protection of neonates against microbial infections.

Cell Adhesion↗
PubMed1985

[Function of neonatal neutrophilic granulocytes].

Phagocytic leukocytes especially neutrophils form an essential part of human host defense against infection by invading microorganisms. The principal activities exhibited by circulating neutrophils in response to inflammation include adherence to vascular endothelium, chemotaxis, phagocytosis and microbial killing. As reviewed in this article, each of these aspects of cell function has been studied in neutrophils of newborn and preterm infants. The most consistent finding has been abnormal chemotaxis. Whether the newborn infant who suffers from an increased susceptibility to serious infections is actually predisposed to infection because of deficiencies in neutrophil function remains questionable. It seems likely that subnormal phagocyte function combined with other defects in host defense such as deficient complement and opsonizing activity in neonatal sera could predispose the newborn infant to bacterial infections that rapidly become systemic.

Bacterial Infections↗
PubMed1985

[Early diagnosis of neonatal infection].

In 93 preterm and term infants with proven neonatal septicemia and/or meningitis different leukocyte indexes were evaluated at onset of septicemia [absolute neutrophil count, immature neutrophil count, immature to total neutrophil ratio (I/T-ratio)]. 75% of the patients who developed septicemia within the first three days of life and 60% of all neonates with septicemia or meningitis could be identified by an elevated I/T-ratio, the most sensitive leukocyte count. Thrombocytopenia was observed in only 33% of the patients. Additional analysis of IgM and fibrinogen was neither helpful in identifying neonatal infections nor a valuable follow-up parameter of successful treatment. In contrast C-reactive protein (CRP) was increased in 88% of all infants with neonatal septicemia and/or meningitis at time of diagnosis; when used in combination neutrophil indexes and CRP even improved the sensitivity of a single laboratory screening test.

C-Reactive Protein↗
PubMed1984

Reactivation of fetal erythropoiesis during the postnatal period.

Using isopycnic gradient centrifugation, blood samples from adults, from umbilical cord, from newborn infants and from infants of different age group up to the age of 8 mo, were separated into seven fractions according to cellular age. We measured the number of erythrocytes and reticulocytes, mean cellular volume, mean cellular hemoglobin concentration, and the concentration of hemoglobin in each of the seven fractions. The distribution of erythrocytes within the gradient during postnatal aging revealed a bimodal distribution between 2-4 mo. Correspondingly, during the age of 2-8 mo the oldest cells did not contain the highest hemoglobin F concentration as was observed in the younger age group. From these data we conclude that the postnatal disappearance of hemoglobin F is not a continuous process.

Adult↗
PubMed1983

Impaired metabolic function of polymorphonuclear leukocytes in glycogen storage disease Ib.

To elucidate the basis for the recurrent infections in patients with glycogen storage disease (GSD) Ib we tested polymorphonuclear leukocyte (PMN) function in one patient. Bactericidal capacity and phagocytosis-induced O2 consumption were reduced. Also, phorbol myristate acetate-stimulated superoxide production and glucose oxidation through the hexose monophosphate shunt were diminished compared to control subjects. Therefore it could be speculated that in PMN of patients with GSD Ib, glucose-6-phosphate has no access to the enzymes of the hexose monophosphate shunt due to a transport-related defect as shown for glucogenesis in hepatocytes.

Female↗
PubMed1983

Sequential determination of CRP, alpha 1-antitrypsin and haptoglobin in neonatal septicaemia.

In 312 preterm and term newborn infants serum concentrations of C-reactive protein (CRP), haptoglobin and alpha 1-antitrypsin were measured during several days by radial immunodiffusion. In addition white blood cell count and the ratio of band to total neutrophils (B/N-ratio) were determined. In 12 infants with proven sepsis CRP was found elevated above the upper limit of the normal range (20 mg/l). Successful therapy was followed by a decrease of CRP concentration. In infants with suspected infection high CRP values were found in most cases. In contrast, haptoglobin and alpha 1-antitrypsin concentrations differed not significantly between the group of infants without infection, with proven and with suspected infection. White blood cell count and B/N-ratio also were not appropriate for the early identification of bacterial infection in the newborn period.

C-Reactive Protein↗
PubMed1983

Plasma levels of catecholamine metabolites in the newborn period.

Plasma levels of homovanillic acid (HVA) and vanillylmandelic acid (VMA) were measured mass fragmentographically in 37 healthy preterm infants and 62 healthy infants born at term during the postnatal period. HVA and VMA levels increased after birth and declined steadily afterwards. Infants with various clinical problems showed marked elevations of HVA and VMA during episodes of clinical deterioration. The results indicate a readily functioning sympathoadrenal system in newborns.

Adrenal Glands↗