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Biomedical subjects

G Hoffmann

Publications and source records attributed to G Hoffmann.

At least 181 records · Page 10Linked to original sources
PubMed1987

New diagnostic techniques for the detection of organic acidemias.

We describe an improved procedure for the extraction of organic acids which is equally suitable for urine, plasma and amniotic fluid and gives similar high recoveries for a wide variety of organic acids, without interferences from phosphate, sulfate, or urea. Internal standards are added, the oxoacids are converted to the pentafluorobenzyloximes; the sample is concentrated, acidified, chromatographed on a small column of silicic acid, and the effluent neutralized and dried. After forming the trimethylsilyl derivatives, gas chromatography is done on a 0.53 mm X 30 m low-polarity bonded-phase fused silica capillary column. For gas chromatographic-mass spectrometric quantification, the peak areas at the m/z of a characteristic fragment ion for each acid relative to the peak areas of ions of the internal standards are related to standard curves.

Adult↗
PubMed1987

[Development of resistance in health pests including ectoparasites-- definition and present situation].

The increasing formation of resistance of ectoparasites and other pests may only delayed if the causes and mechanisms of this development are recognized. On the basis of the genetic classification (definition) of resistance formation, concrete measures to achieve a delay (slow-down) of this process may be taken in the control of different pests and parasites, such as the regular exchange of certain agents or the coordination of measures. The scope of such measures will depend on the concrete resistance situation at the site in question related to the pest species to be controlled, and if necessary, even on the target strain. A survey of the factors to be taken into consideration as well as the present resistance situation of individual European species is presented.

Animals↗
PubMed1987

[Isolation of chlorphenoxamine metabolites in human urine and their identification].

After the administration of chlorphenoxamine (2-[1-(4-chlorophenyl)-1-phenylethoxy]-N,N-dimethylethanamine++ +, Systral) (I) the following compounds have been detected in human urine. They were identified as chlorphenoxamine (I), N-demethyl-chlorphenoxamine (II), chlorphenoxamine-N-oxide (III), 1-(4-chlorophenyl)-l-phenylethanol (IV), 1-(4-chlorophenyl)-1-(4'-hydroxyphenyl)-ethanol (V), 1-(4-chlorophenyl)-1-(4'-hydroxyphenyl)-ethene (VI), 1-(4-chlorophenyl)-1-(4'-hydroxy-3'-methoxyphenyl)-ethanol (VII), 1-(4-chlorophenyl)-1-(4'-hydroxy-3'-methoxyphenyl)-ethene (VIII), 2-[1-(4-chlorophenyl)-1-(4'-hydroxyphenyl)-ethoxy]-N-methyl-ethanamine (IX) and 2-[1-(4-chlorophenyl)-1-(4'-hydroxy-3'-methoxyphenyl-ethoxy]- N-methylethanamine (X). The compounds IV, V, VI, VII, VIII, IX and X were also found to be excreted as conjugates. It cannot be excluded that the compounds VI and VIII are artefacts.

Adult↗
PubMed1986

Mevalonic aciduria--an inborn error of cholesterol and nonsterol isoprene biosynthesis.

A two-year-old boy presented with severe failure to thrive, developmental delay, anemia, hepatosplenomegaly, central cataracts, and dysmorphic features. Quantitative analyses of urinary organic acids revealed massive excretion of mevalonic acid, a metabolic precursor of cholesterol and nonsterol isoprenes: 46,000 to 56,200 mmol per mole of creatinine, as compared with 0.2 to 0.3 mmol per mole in normal children. The mevalonic acid concentration in plasma was also greatly increased at 440 mumol per liter (normal, less than 0.05). The activity of mevalonate kinase, the enzyme that catalyzes the first step in mevalonate metabolism, was severely deficient in the patient's fibroblasts, lymphocytes, and lymphoblasts. In the subsequent pregnancy of the patient's mother, gas chromatography-mass spectrometry demonstrated a marked elevation of mevalonic acid in the mother's urine and a 3000-fold elevation, as compared with control levels in the amniotic fluid, suggesting that the fetus was affected. The diagnosis was confirmed by demonstration of the deficiency of mevalonate kinase in amniocytes and ultimately in liver from the abortus. Intermediate activities of the enzyme in both parents indicated an autosomal recessive mode of inheritance. These observations identify an inherited disorder of cholesterol and nonsterol isoprene biosynthesis in humans.

Amniotic Fluid↗
PubMed1986

[Cleavage of 2-phenylpropan-1-ol and 2-phenylpropan-2-ol-glucuronide, 2 metabolites of isopropylbenzol (Cumol)].

The behaviour of 2-phenyl-1-propanol (I) and 2-phenyl-2-propanol (II) and their glucuronides with HCl has been investigated. While I shows a high acidic constancy, II undergoes a partial conversion into 2-phenylpropane (III) which itself yields numerous products. The glucosidic bond of glucuronide I is quantitatively split by 10.0% HCl, whereby an aglucone yield of nearly 100% is obtained. The second glucuronide behaves otherwise: the recovery of II is very low (only 40% to 45%) with HCl concentrations of 1.0%-20.0%, although with 1.0% HCl 100% of the glucuronide is hydrolysed.

1-Propanol↗
PubMed1986

Hyper-2-oxoglutaric aciduria in long-term mental handicap.

One thousand one hundred and seventy-five mentally retarded patients in an institution (733 males and 442 females) were screened for urinary excretion of 2-oxoacids using a quantitative gas chromatographic method. On follow-up, in 10 out of 31 male patients with excretion of greater than or equal to 50 mmoles 2-oxoglutaric acid per mole creatinine, a previously unrecognized bacteriuria was considered the cause of hyper-2-oxoglutaric aciduria. Of the remaining 21, nine had elevated blood citric acid, and four had borderline elevations of blood pyruvic and/or 2-oxoglutaric acid. In the 11 males with persistent hyper-2-oxoglutaric aciduria an increased incidence of seizure disorders and cerebral palsy relative to the total patient population was found. Hyper-2-oxoglutaric aciduria with concomitant abnormalities of blood metabolites is thought to represent a heterogeneous group of mild inborn errors of energy metabolism which may be compatible with survival at least into young adulthood, but not with normal development of mental and neurological functions.

Adult↗
PubMed1986

[Simultaneous 201Tl/99mTC seven-pinhole tomography in acute myocardial infarct].

Combined infarction scintigraphy with 201Tl-chloride and 99mTc-pyrophosphate (PPi) by simultaneous seven-pinhole tomography was investigated with a phantom as well as in patients. No artificial defects occurred when the collimator was centered correctly in axial position, but a very high standard of image uniformity and linearity of the gamma camera was required. Artefacts by overlying activity from the skeleton or cardiac blood pool were not observed. All 11 controls showed normal results. Despite a poor depth resolution due to limitations of the system even small areas of partially damaged myocardium could be recognized and correlated three-dimensionally. Of 24 patients with proven myocardial infarction, in 16 both a positive (99mTc-PPi) and a negative (201Tl) image was obtained in congruence with the necrosis. 8 patients (33%) showed discordant results providing however additional information on the nature and extent of the necrosis. 4 out of 6 non-transmural infarctions seen by tomography had been suspected clinically.

Adult↗
PubMed1986

[Radiological contribution to the treatment of primary and secondary liver tumors].

The prognosis of patients with primary and secondary liver tumors has been improved recently by more aggressive operative, chemotherapeutic and embolization treatments. In a personal series of 40 patients with liver metastases from colorectal cancer, regional intra-arterial chemotherapy was superior to systemic intravenous treatment, with a tumor remission rate of 66% in comparison to 48% of the cases. But the benefit of intra-arterial chemotherapy is still questionable considering the higher complication rate and the absence of prognostic data of the procedure.

Adult↗
PubMed1985

Sleep EEG recordings in depressive disorders.

Sleep polygraphic recordings were performed during 3 consecutive nights in a sample of 43 affectively ill inpatients. The patients were classified as major (n = 36) or minor depressive disorder (n = 7), according to the Research Diagnostic Criteria. Among the 36 patients with a major depressive disorder, 14 were in remission at the time of the sleep investigation. A two-way analysis of variance was performed to assess night and diagnostic effect on sleep variables. Shortening of REM latency was observed in depressed patients with major depressive disorder when compared to major depressive disorder patients in remission. Depressed patients with major depressive disorder also showed higher REM activity and REM density values than patients with minor depressive disorder. According to the linear discriminant analysis, sleep variables were able to correctly classify 68% of the patients.

Adult↗
PubMed1985

Effects of ECT on sleep and CSF biogenic amines in affective illness.

The effects of electroconvulsive therapy (ECT) on sleep and cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) were studied in 11 male patients suffering from major depressive disorders severe enough to require ECT. Total sleep time and sleep efficiency index increased significantly after ECT, while the number of awakenings, the ratio wake/total sleep time, and the time of intermittent awake decreased, indicating that sleep continuity improved after treatment. Sleep architecture was also favorably influenced by ECT as shown by a significant increase in time of stage 2 and rapid eye movement (REM) sleep. REM latency and REM density also normalized after ECT. CSF 5HIAA increased significantly after ECT, but this was not the case for CSF HVA. These results demonstrate a positive effect of ECT on sleep EEG and CSF neurochemical markers for depressive illness.

Adult↗