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Biomedical subjects

D Mathias

Publications and source records attributed to D Mathias.

28 records · Page 2Linked to original sources
PubMed1987

Clinical significance and source of raised catalytic activities of phosphohexose isomerase in the CSF in meningitis.

The value of phosphohexose isomerase (EC 5.3.1.9) determination in the CSF in the diagnosis of meningitis was tested under routine conditions. In 48 patients with untreated bacterial meningitis, enzyme activity concentrations between 40 and 2335 U/l were measured, whereas the highest phosphohexose isomerase activity concentration in 92 patients with viral meningitis was 34 U/l. Lysis of the CSF leukocytes with Triton X-100 resulted in a substantial increase of phosphohexose isomerase activity. In bacterial meningitis these values increased to 200 to 7000 U/l, but remained under 150 U/l in viral meningitis. The raised enzyme activities are derived from the leukocytes and appear to reflect their functional and metabolic state. The information provided by the leukocyte morphology can thus be appreciably extended by phosphohexose isomerase determination.

Adolescent↗
PubMed1987

[Possible interfering factors in the screening of newborn infants for inborn errors of metabolism and measures for their prevention].

From taking a sample to communicating the result, the success of neonatal screening is endangered by a series of pitfalls. Besides internal and external quality control and an adequate practical experience due to high sample throughput, it is important to know these possibilities of errors in order to be able to reduce them to a minimum in daily routine work.

False Positive Reactions↗
PubMed1986

Follow-up study of 16 years neonatal screening for inborn errors of metabolism in West Germany.

Capillary blood samples from almost one million neonates from Baden-Württemberg were investigated for inborn errors of metabolism between 1969 and 1984 in our screening centre. Besides 7 patients with maple syrup urine disease (MSUD), 3 with homocystinuria and 18 with galactosaemia, a follow-up of the positive screening results confirmed 94 patients with phenylketonuria (PKU) and 76 with non-PKU hyperphenylalaninaemia (non-PKU HPA). The incidence of PKU is 1:10000, and that of HPA in the wider sense (PKU and non-PKU HPA) as obtained by newborn screening before further classification at 6 months 1:5532. For West Germany as a whole, the number of newly discovered cases with persistent hyperphenylalaninaemia was 1480 in the same period. The subdivision into PKU and non-PKU HPA is not yet possible from this figure. It is strongly suggested that the abnormal results of newborn screening for phenylalanine be designated as hyperphenylalaninaemia (in the wider sense) and that the terms "PKU" or "non-PKU HPA" be used only after further differentiation as carried out by us at the age of 6 months.

Capillaries↗
PubMed1986

Growth hormone secreting pituitary adenomas are heterogeneous in cell culture and commonly secrete glycoprotein hormone alpha-subunit.

Cell culture methods were used to assess whether human pituitary adenomas secreting GH and associated with clinical acromegaly also secreted the structurally unrelated glycoprotein hormone alpha-subunit. Thirty-two tumours, together with peri-adenomatous tissue from two of them and three normal pituitaries were studied. Anterior pituitary hormones were measured by radioimmunoassay and included PRL, TSH, LH, FSH, and ACTH, as well as GH and alpha-subunit. Normal pituitary tissues secreted all hormones assayed. All 32 tumours secreted GH ranging from 241 to 5556 ng/2 X 10(5) cells/24 h and 12 (37.5%) secreted alpha-subunit in amounts which could not be accounted for by cross-reaction of other hormones or contamination by normal pituitary tissue, and which ranged from 10.3 to 73.5 ng/2 X 10(5) cells/24 h. Ten other tumours also secreted alpha-subunit but in very small amounts, not exceeding 1.8 ng/2 X 10(5) cells/24 h. PRL was secreted from 21 tumours (66%), and small amounts of other hormones, chiefly LH and TSH, were occasionally secreted from tumours. These cell culture studies would suggest that pituitary adenomas causing acromegaly are hormonally heterogeneous and that PRL and glycoprotein alpha-subunit are commonly detected in addition to GH.

Adenoma, Acidophil↗
PubMed1985

Inter-laboratory quality control in neonatal screening for inborn errors of metabolism.

Screening of neonates for inborn errors of metabolism has been carried out on a national level since 1969 in the Federal Republic of Germany. To raise the reliability of these routine investigations, we introduced an external quality control in March 1982. Every 2 months ten filter paper samples were sent to the screening centres in West Germany. Some of these samples have a normal and others a slightly raised content of phenylalanine, leucine, methionine and galactose. The success of this external quality control is appraised on the basis of the number of false negative results. In the course of time, screening centres in France, Israel, Italy, Japan, Switzerland, Taiwan, Turkey and Yugoslavia have also participated in these inter-laboratory quality controls.

Diagnostic Tests, Routine↗
PubMed1985

Effects of growth hormone-releasing factor (1-44) on growth hormone release from human somatotrophinomas in vitro: interaction with somatostatin, dopamine, vasoactive intestinal peptide and cycloheximide.

The effect of GH-releasing factor(1-44)(GRF) alone, or together with somatostatin (SRIF), dopamine (DA), vasoactive intestinal peptide (VIP) or cycloheximide was studied in a total of ten human somatotrophinomas using a static cell culture system. Growth hormone-releasing factor (2.0 X 10(-8) mol/l) significantly (P less than 0.05) stimulated GH release from nine out of ten tumours over 4-h incubations, and a dose-related effect (2.0 X 10(-10) -2.0 X 10(-8) mol/l) was observed in five tumours thus studied. Repeated GRF (2.0 X 10(-8) mol/l)-mediated GH release was seen during 96% (n = 25) of experiments performed on six tumours over 4 h and up to 27 days in culture. Growth hormone-releasing factor (2.0 X 10(-8) mol/l) also stimulated GH release from five out of seven somatotrophinomas during 60-min incubations. Somatostatin (6.1 X 10(-9) mol/l) completely inhibited GRF-induced GH secretion from four tumours studied over 4 h, but in each case there was significant (P less than 0.05) 'rebound' of GH release from cultures exposed to both GRF and SRIF during a subsequent recovery period. Dopamine suppressed basal GH release from two out of four tumours, but in each case had a greater inhibitory effect on GRF-mediated GH release. Vasoactive intestinal peptide directly stimulated GH release from two out of three tumours, and the effects were additive to maximal stimulatory doses of GRF. Cycloheximide significantly (P less than 0.01) enhanced GRF-stimulated release of GH during a 60-min incubation, but inhibited both basal and GRF-stimulated release over 4 and 8 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1985

Cholesterol determination in serum after fractionation of lipoproteins by immunoprecipitation.

We investigated the immunoprecipitation of apolipoprotein B-binding lipoproteins, or of apo A-I- and apo C-binding lipoproteins, by delipidated antiserum for measuring cholesterol in the nonprecipitated lipoprotein fractions. After immunoprecipitation of serum with delipidated anti-apo B, we determined by immunoelectrophoresis that no beta- or pre-beta lipoproteins were present, whereas alpha-lipoproteins remained in the supernate. Conversely, after immunoprecipitation with an antiserum against apo A-I + apo C, only lipoproteins with beta-mobility were detected and no apo B from beta-lipoproteins was in the precipitate. The concentration of cholesterol in the supernate after immunoprecipitation with anti-apo B correlated highly (r = 0.93, n = 118) with cholesterol measured after precipitation with phosphotungstic acid/MgCl2. The cholesterol concentration after immunoprecipitation with anti-apo AI and anti-apo C correlated similarly well (r = 0.94, n = 145) with the LDL-cholesterol calculated by Friedewald's formula in serum specimens reflecting moderate hyperlipoproteinemia.

Apolipoproteins↗
PubMed1980

Phosphohexose isomerase in cerebrospinal fluid in meningitis.

The diagnostic value of determining phosphohexose isomerase (PHI, E.C. 5.3.1.9) activity in the CSF for differential diagnosis of bacterial and viral meningitis was investigated. In 29 patients with untreated bacterial meningitis, a mean enzyme activity of 511 U/1 was found, whereas a value 19 U/1 was found in 61 cases of viral meningitis. The reference range with an upper limit of 6 U/1 was determined from CSF samples from 163 "healthy" children. The high diagnostic sensitivity and specificity of 100% and 99.5% respectively make PHI a sensitive differential diagnostic parameter in meningitis.

Adolescent↗
PubMed1975

Skin and homograft cartilage reconstruction.

Conservative vertical hemilaryngectomy poses the problem of relating the need to remove the tumor completely to the aim of reconstructing an adequate airway lined with epithelium. An attempt has has been made in experimental animals to overcome this problem using pedicled skin and homograft cartilage. The findings suggest that this is a feasible technique, although somewhat hampered by problems unique to the animals concerned. The use of skin pedicles provides adequate cover without shrinkage, and although it is doubtful whether cartilage can survive intact in the long-term, it would seem that it may be adequate for the purposes intended.

Airway Resistance↗