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Biomedical subjects

W Bürgi

Publications and source records attributed to W Bürgi.

At least 19 recordsLinked to original sources
PubMed1995

Immunoglobulin subclass concentration in preterm infants treated prophylactically with different intravenous immunoglobins.

The most immature infants have critically low concentrations of all immunoglobulin G (IgG) subclasses, associated with a higher risk for pyogenic, respiratory, and meningeal infection. Selective IgG subclass deficiency is an established indication for intravenous immunoglobulin (IVIG) substitution. However, considering that therapeutic efficacy of IVIG is dependent on its pharmacokinetics, we studied peak and trough IgG subclass serum levels during the neonatal period (28 days) in a group of 34 healthy preterm babies (30.2 +/- 2 weeks gestational age (GA) and 1065 +/- 210 g birthweight (BW) treated prophylactically with three daily standard doses of two different IVIG preparations: Sandoglobulin (SG) (0.5 g/kg/day) and Pentaglobin (PG) (5 mL/kg/day). IgG subclass levels were assayed by radioimmundiffusion (RID) before treatment (day 1) and at days 3, 5, 7, 14, and 28 of life. Statistical analysis was performed by paired t test. In the first week of life only (days 3, 5, 7), for both IVIG preparations, subclass levels were higher than pretreatment values: IgG1, 4.6 +/- 1.7 versus 5.6 +/- 1.6 g/L; IgG2, 1.6 +/- 0.8 versus 2.1 +/- 0.6 g/L; IgG3, 0.2 +/- 0.7 versus 0.3 +/- 0.1 g/L; IgG4, 0.3 +/- 0.1 versus 0.9 +/- 0.1 g/L (p < 0.05). During this time (7 days) IgG2 levels were higher in the SG group and IgG4 was higher in the PG group (p < 0.05). This study shows pretreatment IgG subclass levels 14 days after treatment and different patterns, depending on the used preparation. We conclude that prospective clinical trials should include the study of target serum levels and timing of IVIG administration not only for IgG but also for IgG subclasses.

Bacterial Infections↗
PubMed1995

[The hematological laboratory of clinical practice].

The spectrum of analyses of a hematological laboratory comprises the counts of erythrocytes, leukocytes and platelets, the determinations of the hemoglobin concentration and of the hematocrit, the calculation of the red cell indices and the microscopic examination of the blood film. The determination of white blood cells, platelets, hematocrit and MCV as well as staining of the blood film should be performed within two hours after blood sampling. The hemoglobin concentration, red-cell count and MCH value remain constant for five days, provided that the blood samples is stored at 4 degrees C. The recognition of morphologically 'minor' pathological findings is important in view of the possible clinical significance that they might have. In the case of thrombotic-thrombocytopenic purpura, for instance, it is very important that the fragmentocytes are recognized and recorded. The grading of pathological findings by use of +, ++, is based on strict limits of ranges. Quality control and quality assurance are integral parts of the daily laboratory performance; moreover, the importance of external quality control in morphological hematology is stressed as being a challenge to the hematological laboratory technologist.

Blood Cell Count↗
PubMed1993

[Demonstration of intrathecal antibody formation against Borrelia burgdorferi in Lyme neuroborreliosis].

Neurologic complications are common in Lyme borreliosis. In adults in particular, detection of intrathecally formed antibodies to B. burgdorferi is a decisive diagnostic criterion. As in neurosyphilis diagnosis, the specific antibody titer against B. burgdorferi in the CSF is compared with the serum titer by calculating the specific antibody indices, taking into account the disturbed blood/CSF barrier. Deriving from these specific indices, we adapt by dilution the serum IgG level to that in the CSF of the same day, thus allowing for passive diffusion of antibody through the blood/CSF barrier. Determination of the specific antibody titer by indirect immunofluorescence demonstrates intrathecal synthesis of specific antibodies against B. burgdorferi if the CSF titer is higher than in the diluted serum tested in parallel. The individual methods are presented in a group of patients.

Adult↗
PubMed1993

Fetal haemoglobin levels in adult type 1 (insulin-dependent) diabetic patients.

Glycated haemoglobin levels (HbA1 and HbA1c) are established parameters of long-term glycaemic control in diabetic patients. Depending on the method used, fetal haemoglobin interferes with the assays for glycated haemoglobin. If present in high amounts, fetal haemoglobin may lead to overestimation of glycated haemoglobin levels, and therefore, of average blood glucose concentration in diabetic patients. Glycated (HbA1c) and fetal haemoglobin levels were measured by high pressure liquid chromatography in 60 (30 female) adult Type 1 (insulin-dependent) diabetic patients of Swiss descent, and were compared with levels obtained from 60 normal, non-diabetic control subjects matched for age and sex. Fetal haemoglobin levels were significantly higher in the diabetic patients (0.6 +/- 0.1%, mean +/- SEM; range: 0-3.6%) than in the control subjects (0.4 +/- 0.1%, p < 0.001). Elevated fetal haemoglobin levels (> or = 0.6%) were found in 23 of 60 diabetic patients (38%) compared to 9 of 60 control subjects (15%; chi 2 = 8.35, p < 0.01). In addition, fetal haemoglobin levels in diabetic patients are weakly correlated with glycated haemoglobin (HbA1c) (r = 0.38, p < 0.01). Fetal haemoglobin results were confirmed with the alkali denaturation procedure, and by immunocytochemistry using a polyclonal rabbit anti-fetal haemoglobin antibody. A significant proportion of adult patients with Type 1 diabetes has elevated fetal haemoglobin levels. In certain patients this may lead to a substantial over-estimation of glycated haemoglobin levels, and consequently of estimated, average blood glucose levels. The reason for this increased prevalence of elevated fetal haemoglobin remains unclear, but it may be associated with poor glycaemic control.

Adolescent↗
PubMed1993

Serial IgG and IgM serum levels after infusion of different Ig-preparations (IgG or IgM-enriched) in preterm infants.

Intravenous administration of Immunoglobulin (IVIG) has been used for prevention or treatment of neonatal sepsis. However, therapeutic efficacy of IVIG is dependent on pharmacokinetic factors. There have been no comparative studies in neonates between licensed IgG and IgM enriched preparations. The aim of this study was to investigate serial IgG and IgM serum levels during the neonatal period in two groups of non-septic, preterm infants treated prophylactically with IVIG. Twenty-two very low birth weight (VLBW) patients (1001-1500g) (gestational age 31.8 +/- 2.0 weeks and 1265 +/- 245g birth weight) and 12 extremely low birth weight (ELBW) patients (< 1000g) (gestational age 28.6 +/- 2.5 weeks and 910-85g birth weight) received at random three standard doses of Sandoglobulin (SG) (0.5 g/kg/day) or IgM enriched Pentaglobin (PG) (5 ml/kg/day). IgG and IgM concentrations were assayed by rate nephelometry before treatment and at day 3, 5, 7, 14 and 28 of life. At any time IgG levels were higher in the SG-VLBW group (p < 0.01), no difference being observed in the ELBW group (p > 0.5). IgM levels were higher at day 3 and 5 in the PG-VLBW group and until day 7 in the ELBW group (p < 0.01). This study indicates a wide range of IgG and IgM kinetics in the healthy premature and suggests frequent monitoring of immunoglobulin serum levels during efficacy studies.

Humans↗
PubMed1992

[Dry chemistry in the clinical laboratory: how reliable is it?].

The performance of dry chemistry analysis systems was evaluated using the results obtained from proficiency testing 1991 of practitioner's laboratories. 59% of the participants use dry chemistry (Ektachem DT 60 Kodak, Reflotron Boehringer, Cobas Ready Roche). The evaluation reveals the following: The declared values of the control sera for the dry chemistry systems agree well with those of the conventional wet chemistry, excepting enzyme assays. The precision of the dry chemistry parameters is substantially higher than that of the wet chemistry. The overall performance of the dry chemistry analysis systems was found to be superior as compared to the wet chemistry performance. A prerequisite for dry chemistry proficiency testing are control sera of human origin.

Clinical Enzyme Tests↗
PubMed1992

[Non-enzymatic marking of gene probes using digoxigenin for the diagnosis of sickle cell mutation and beta thalassemia].

A method is described in which allele-specific oligonucleotides (ASO) are labeled non-enzymatically with digoxigenin (DIG). The ASOs were synthesized in a DNA synthesizer. A primary C6-alkylamine was incorporated at the 5'end of the ASO. The derivative was coupled to digoxigenin-3-0-methylcarbonyl-epsilon-aminocaproic acid-N-hydroxy-succinimide ester. The DIG-ASO probes were isolated from the crude preparation and hybridized with amplified genomic DNA. The annealed probes were detected with an ELISA test. The DIG-ASO probes were successfully used for the identification of sickle cell disease genotypes and the most common beta-thalassemia mutations.

Adult↗
PubMed1992

[Acquired hemoglobin H disease in the early stage of erythroleukemia].

At the onset of erythroleukemia, the patient, a 74-year-old Swiss male, was also found to have microcytic-hypochromic anemia (Hb: 82 g/l, MCV: 69 fl, MCH: 21 pg). Further laboratory examinations revealed reduced hemoglobin stability, a hemoglobin H fraction of 3.0% on cellulose acetate-electrophoresis, and an abundance of hemoglobin H inclusion bodies in red cells. These findings, as well as the Swiss origin of the patient and his age at the onset of the disease, were consistent with acquired hemoglobin H disease. In addition to genetic hemoglobin H disease, acquired hemoglobin H disease was reported to be associated with myelodysplastic and myeloproliferative syndrome, or erythroleukemia and acute myelogenous leukemia. The literature contains fewer than 50 cases. It is suggested that the molecular basis of this rare disease involves a gene in trans to the alpha-globin genes reducing the expression of all four alpha-globin genes to approximately 10% of normal activity.

Aged↗
PubMed1991

[Platelet satellitosis].

Platelet satellitism (PS) is a rare phenomenon described sporadically in the literature. It involves adhesion of thrombocytes sensitized by antibodies to leucocytes and is observed in vitro in EDTA anticoagulated blood. The authors' contribution to the problem is the observation of special thrombocyte aggregates surrounding neutrophils resembling comet tails, as well as the fact that the authors observed the formation of aggregates surrounding also lymphocytes and eosinophil cells.

Aged↗
PubMed1989

[Congenital methemoglobinemia with cytochrome-b5-reductase deficiency: 4th Swiss family].

In a female newborn presenting with pronounced cyanosis in the absence of cardiopulmonary disease, the cyanosis was due to methemoglobinemia of 33% at birth and 17% at 24 hours (upper limit 0.5%) which was found to be secondary to deficiency of red blood cell cytochrome b5 reductase (EC 1.6.2.2.). Only residual activity of this enzyme was measurable, thus indicating homozygosity. Both parents were found to be heterozygous for this inherited disease. Of the six sisters and brothers of the newborn's father, five were investigated and all found to be heterozygous for the defective allele. Measurement of cytochrome b5 reductase showed both soluble and membrane bound fractions to be affected equally in the red cells of the baby's heterozygous parents.

Adult↗
PubMed1989

Automated blood count analysis by trimodal size distribution of leukocytes with the SYSMEX E-5000.

The automated haematology analyser, SYSMEX E-5000, measures and computes quantitative haematological parameters, and determines the size distribution of blood cells and platelets. After partial lysis, the analyser classifies the leukocytes into 3 populations: small cells (lymphocytes), intermediate sized cells (basophils, eosinophils, monocytes) and large cells (neutrophils, including band cells). One thousand blood samples from inpatients and outpatients were analysed automatically in the SYSMEX as well as being submitted to microscopic blood smear differentiation, and the results were compared. The trimodal size distribution of the automated analysis revealed 1.8% false normal results. Ten cases of eosinophilia of between 6.6 and 12.5% remained undetected by the automated method, which also failed to detect 7 cases of left shift with normal leukocyte count, as well as a single sample containing 2% of myelocytes. Both diagnostic sensitivity and diagnostic specificity were high, i.e. 97.1% and 81.8%, respectively. The predictive values were also high for both pathological and normal results. Since certain changes in blood cell morphology are not detected by the SYSMEX, certain clinical indications still call for a microscopic blood smear examination. With due regard to these limitations, the apparatus yields reliable results and economizes considerably the routine laboratory work load. In the present study, 31% of the microscopic blood cell differential counts were saved by using the SYSMEX E-5000.

Humans↗
PubMed1989

Unusually high concentrations of Zn alpha 2-glycoprotein and the lack of alpha 2HS-glycoprotein in human ejaculates.

Ejaculates of 132 nonvasectomized and 129 vasectomized men were assayed for their Zn alpha 2- and alpha 2HS-glycoprotein contents by radial immunodiffusion. The respective mean concentrations of Zn alpha 2-glycoprotein were 319 and 309 mg/L, respectively, but these fluids were devoid of alpha 2HS-glycoprotein. In comparison, the concentration of these two proteins in serum of normal men were 62 and 617 mg/L for Zn alpha 2- and alpha 2HS-glycoprotein, respectively. Because albumin in the ejaculates is 100-fold less concentrated than in serum, the fivefold increase in the concentration of Zn alpha 2-glycoprotein of the ejaculates represents about a 500-fold enrichment of this protein in the ejaculates over the concentration expected by comparison with albumin.

Adult↗
PubMed1989

[Method and clinical significance of cerebrospinal fluid spectrophotometry].

The results of the spectrophotometric analysis of 932 cerebrospinal fluid specimens are presented. The specimens were obtained from 95 patients with subarachnoid and intracerebral hemorrhages, 75 patients with traumatic head injuries, 40 patients with infectious diseases of the central nervous system, 302 patients with cerebrovascular accidents and 302 patients suffering from a variety of diseases such as multiple sclerosis, herniated intervertebral discs and vasomotor headache. Normal cerebrospinal fluid is colourless and shows a spectrophotometric absorption characterized by a flat curve with decreasing absorption from 350 to 650 nm. In disease states Oxy-Hemoglobin, Met-Hemoglobin and Bilirubin can be identified in cerebrospinal fluid. These pigments, when present in cerebrospinal fluid, change the spectrophotometric curve due to their specific absorption spectra. According to the quantitative relationship between the pigments and their chronological order of appearance in the cerebrospinal fluid, typical spectrophotometric patterns have been delineated. The spectrophotometric absorption curve of a hemorrhage due to rupture differs from that of a diapedetic hemorrhage. Moreover, tap bleeding results in an absorption curve which can be differentiated early from that of a subarachnoid hemorrhage. Finally, artifacts due to desinfectants can easily be identified. It is concluded that the spectrophotometric analysis of cerebrospinal fluid gives helpful information in subarachnoidal-hemorrhage, subdural and intracerebral hematoma, in contusions of the brain, carcinomatosis of the leptomeninx, spinal tumor and meningoencephalitis of unknown origin.

Bilirubin↗
PubMed1988

One-step sandwich enzyme immunoassay for insulin using monoclonal antibodies.

An enzyme-linked immunosorbent assay for the measurement of insulin in human serum has been developed. The test is based on the sandwich technique with two monoclonal antibodies directed against two different epitopes of insulin using coated plastic tubes as the solid phase and horse radish peroxidase as the label. The immunoreactions are completed in one step within 2 h. The horse radish peroxidase activity bound to the tube wall is measured photometrically after an additional 1-h incubation with the substrate. The standards used cover the range from 0 to 260 mU insulin/L. Employing the Enzymun-Test System ES 22 modular batch analyzer, the detection limit was found to be 3.7 mU insulin/L. Coefficients of variation (CV's) between 1.4-7.8% for intraassay precision and 5.6-10% for interassay precision were obtained over the concentration range of 17-107 mU Insulin/L. The correlation between the procedure described here (y) and a commercially available double antibody radioimmunoassay (x) is expressed by the following equation: y = 1.07x + 1.14 mU insulin/L.

Antibodies, Monoclonal↗
PubMed1988

Complete amino acid sequence of human plasma Zn-alpha 2-glycoprotein and its homology to histocompatibility antigens.

In the present study the complete amino acid sequence of human plasma Zn-alpha 2-glycoprotein was determined. This protein whose biological function is unknown consists of a single polypeptide chain of 276 amino acid residues including 8 tryptophan residues and has a pyroglutamyl residue at the amino terminus. The location of the two disulfide bonds in the polypeptide chain was also established. The three glycans, whose structure was elucidated with the aid of 500 MHz 1H NMR spectroscopy, were sialylated N-biantennas. The molecular weight calculated from the polypeptide and carbohydrate structure is 38,478, which is close to the reported value of approximately equal to 41,000 based on physicochemical measurements. The predicted secondary structure appeared to be comprised of 23% alpha-helix, 27% beta-sheet, and 22% beta-turns. The three N-glycans were found to be located in beta-turn regions. An unexpected finding was made by computer analysis of the sequence data; this revealed that Zn-alpha 2-glycoprotein is closely related to antigens of the major histocompatibility complex in amino acid sequence and in domain structure. There was an unusually high degree of sequence homology with the alpha chains of class I histocompatibility antigens. Moreover, this plasma protein was shown to be a member of the immunoglobulin gene superfamily. Zn-alpha 2-glycoprotein appears to be a truncated secretory major histocompatibility complex-related molecule, and it may have a role in the expression of the immune response.

Amino Acid Sequence↗