Search PubMed⌕ Search

Biomedical subjects

R Sommer

Publications and source records attributed to R Sommer.

At least 91 records · Page 5Linked to original sources
PubMed1982

[The value of visually evoked response in diagnosis of multiple sclerosis ].

We investigated the reliability of visually evoked responses (VER) in 56 cases in diagnosing multiple sclerosis. We found 100% pathological VER in proved cases and 71% in probable/possible cases. Patients with a duration of illness less than one year had in 80% pathological VER, whereas in other conditions only 17% were pathological. Structural changes are usually found in definite multiple sclerosis patients with a disease progress lasting more than 1 year. Pathological VER are an important diagnostic aid in multiple sclerosis, especially in doubtful cases, whereas structural investigations are primarily useful in the exclusion of other conditions.

Adolescent↗
PubMed1982

[Levels of lipoprotein fractions in ischaemic cerebral disease (author's transl)].

The significance of serum lipid levels in the assessment of risk in ischaemic cerebral diseases is controversial. The differential investigation of lipoproteins, however, showed that the high-density lipoprotein (HDL) fractions are absolutely or relatively decreased with respect to low-density lipoproteins (LDL) in cerebral infarcts and in transient ischaemic attacks. Raised LDL/HDL ratios were found in this study, as an expression of a relative lowering in HDL, in ischaemic cerebral disease associated with pathological disorders of the large or small cerebral vessels. Hence, it appears that HDL represents a protection factor, not only in the prevention of cardiovascular, but also cerebrovascular disease and a decrease in HDL may be a risk factor.

Brain Ischemia↗
PubMed1982

Computer programs for the analysis and the management of DNA sequences.

A program package is described for the management and the analysis of DNA sequence data. The programs - with the exception of a few Fortran routines - are written in the programming language APL. They are best used interactively although batch processing is possible. The package has been in constant use for about 3 years and contains programs for most of the routine problems presently found in a DNA sequencing laboratory.

Amino Acid Sequence↗
PubMed1980

[Routine serum digoxin determination on hospital admission (author's transl)].

The purpose of the present study was the collection of data concerning digitalis treatment of patients outside hospital. The investigation was carried out on 200 patients over 60 years of age, consecutively admitted to a 750-bed general hospital (35% ot a medical ward, 65% to other specialities). An ECG and serum creatinine and digoxin determinations were performed on the day of admission and a careful history taken of the drugs administered before admission. 30 patients reported the use of digoxin or other digitalis drugs, whilst another 48 patients reported taking cardiac drugs in general. The prevalence of digoxin levels exceeding 2 ng/ml was 11.5% in the group of patients known to have taken digitalis preparations, 18% among the 92 patients with positive serum digoxin levels and highest (30%) in the subgroup admitted due to cardiac failure. In patients with digoxin levels above 2 ng/ml the prevalence of elevated serum creatinine values (greater than 1.2 mg%) was markedly increased. Among patients with normal serum creatinine levels the mean age of patients with digoxin levels above 2 ng/ml was significantly higher than of those with digoxin levels below 2 ng/ml. A clear correlation between digoxin levels and ECG changes was not demonstrable; simultaneous administration of diuretics promotes the appearance of electrocardiographic signs of digitalis toxicity.

Aged↗
PubMed1980

Sequence of a ribosomal RNA gene intron from Tetrahymena.

Recently, several genes coding for messenger RNA, transfer RNA and ribosomal RNA in eukaryotes have been found to be interrupted in their coding regions by DNA sequences which are not represented in the mature RNA transcripts (see ref. 1 for review). Many of these intervening sequences, or introns, are now known to be transcribed in the precursor RNA, from which they are subsequently processed out to form the mature RNA. As the intron-exon junctions must in some way be recognised for accurate splicing, the nucleotide sequences of these regions from a number of protein-coding and tRNA genes have been analysed. Sequence homologies were found at the splice points of the protein-coding gene introns from diverse organisms, but the tRNA intron boundaries were not similar to these. This has led to the speculation that different splicing activities are necessary for the processing of introns in mRNA and tRNA precursors. We report here the sequence of a ribosomal RNA gene intron from Tetrahymena in which intron-exon junctions differ from those analysed to date.

Base Sequence↗
PubMed1980

[Anticonvulsive combined therapy (author's transl)].

19 patients were treated with valproic acid (VPR) in combination with classical anticonvulsants (phenytoin, phenobarbitone, primidone, carbamazepine). Patients with a mean serum concentration of 340 micron moles/l showed a marked improvement as to the frequency of seizures or were even completely free from seizures, provided that the other anticonvulsants were also given in the therapeutic range. Cases showing only a slight reduction in seizure frequency or no improvement had a mean serum level of 229 micron moles/l. This investigation shows that in severe cases of epilepsy treated by combined therapy all given anticonvulsants must reach therapeutic levels to achieve effective control of seizures in most patients.

Anticonvulsants↗
PubMed1979

[The serum concentration of anticonvulsants -- pharmacokinetic findings and practical therapeutic applications (author's transl)].

Routine determination of the blood serum concentration of most of the usual anticonvulsants is possible by means of an immunoenzymatic method (EMIT). Determination of the total concentration permits conclusions as to the amount of available, unbound and, thus, effective amount of the substance. Regular determination of serum values provides insight into the relevant pharmacokinetics. Metabolism of anticonvulsants differs greatly among individuals and therefore considerable individual variation exists in the relation between the applied dose and the attained serum level. The metabolic rate of the various substances is unequal and, accordingly, the time necessary to reach a steady state and the half life is very variable. Metabolism may be altered by various biological adaptations, diseases or other drugs, causing alterations in the serum level of the anticonvulsant. Results obtained to date indicate a therapeutic threshold concentration range. In a certain percentage of patients seizures are abolished or diminish in frequency only on attaining such a serum level. In more benign cases an adequate therapeutic effect may be obtained with lower ("subtherapeutic") concentrations, while on the other hand, in malignant cases, no efficient control of seizure activity can be attained even at a high serum concentration. The method should be used in all problematic patients. Up to 50% of patients with insufficient control of seizures show improvement or, even, absence of seizures if this method is included in the therapeutic concept.

Antacids↗
PubMed1979

Nucleotide sequence of the recognition site of the B-specific restriction modification system in E. coli.

Two sB mutations in the genome of bacteriophage fd were located by sequence analysis in the fd sequence at positions 971 and 6341. Base changes at or close to these positions in phage M13 and in phage fl am 124 also correlate with a loss of sensitivity to B restriction. From the sequence homology between the sequences at the two sB sites the recognition signal for the E. coli B restriction/modification enzzyme is predicted to be: 5' TGA---8N---TGCT 3' 3' ACT---8N---ACGA 5'.

Base Sequence↗
PubMed1979

Determination of renal clearances of amylase/creatinine with chromogenic and enzymatic methods.

Urinary amylase was estimated by chromogenic (amylochrome Roche) as well as enzymatic methods (SKI and Beckman: substrate starch and substrate maltotetraose respectively). Random and timed urines (24 hour collections) were analysed. Clearances of amylase gave different results dependent upon the amylase-test used and the glomerular filtration rate. Correlation between chromogenic and enzymatic methods (starch as substrate) was poor. The ratio of amylase and creatinine clearance was used to test different methods. Reference values for this ratio for the amylochrome method (N = 106) were 2.85 +/- 0.99% and for the Beckman-DS method (N = 60) 2.82 +/- 0.87%.

Amylases↗
PubMed1979

[Determination of alpha-amylase by an enzymatic kinetic method on the ABA-100 (author's transl)].

The enzymatic method of H. W. Schiwara (1972) Z. Klim. Chem. Klin. Biochem. 10,12--16 (reagents by Smith Kline Instruments), using the enzymatic reaction sequence alpha-amylase -- alpha-glucosidase -- hexokinase/glucose 6-phosphate dehydrogenase for the determination of alpha-amylase was evaluated on the ABA-100. The coefficient of variation for control sera and human pooled serum was 0.9--4.2% within series, and 1.4--6.6% day to day. Reference values for a healthy population (212 blood donors) in sera were 13--79 U/1 (+/- 2 SD), mean 46 U/1. In catch urines the values did not show a normal distribution; the minimal and maximal range for men was 58--385 U/1, for women 7--318 U/1. The kinetic curve of the enzymatic test was measured and the influence of glucose and linearity studied. In comparison with the enzymatic test, the chromogenic method Amlyochrom Roche was tested on the sera and urine of patients. The coefficient of correlation in sera was r = 0.975, in urine r = 0.965.

Amylases↗
PubMed1979

[Pathogenesis of ketotic hypoglycemia (author's transl)].

4 children with ketotic hypoglycemia (KH) showed during a fasting period over 24 hours significant higher decreases of serum alanine levels than normal controls. Insulin induced hypoglycemia was followed by only minimal increase of urine epinephrine secretion, while all controls showed more than 6 times higher increases. 2-desoxy-glucose-tests were pathological in all cases with KH. One can speculate, that there is a connection between the reduced availability of alanine and the adrenal medullary hyporesponsiveness. Epinephrine stimulates glycogenolysis in muscle cells. Lack of epinephrine reduces pyruvate production and subsequently alanine synthesis. Alanine however is essential for gluconeogenesis in liver cells especially during starvation. After some days administration of diazoxide the 2-desoxy-glucose-test was normalised in all patients. This observation could probably be of some interest in therapy of KH.

Acidosis↗
PubMed1978

[A simple and quick method for measuring low blood-glucose concentrations (author's transl)].

A new method of measuring glucose concentrations (Reflotest-Hypoglycemie) was tested on 141 serum samples and 119 capillary blood samples and compared with the hexokinase-glucose-6-phosphate dehydrogenase method. The Reflotest (reflectance meter) compared well with the reference test. Comparison of results with three sera measured by the method in six different laboratories indicated the accuracy of the test. Endogenous bilirubin, uric acid, and haematocrit values did not influence the result. The test is therefore suitable for quantitative measurements.

Bilirubin↗
PubMed1978

Structure of the orgin of DNA replication of bacteriophage fd.

An RNA-polymerase-protected DNA fragment of 125 nucleotides from the origin of single-strand to double-strand replication of bacteriophage fd (ori-DNA) was located on the physical map of the phage genome. A stretch of 187 base pairs of DNA including the ori-DNA was sequenced. This DNA segment contains regions with a highly asymmetric pyrimidine/purine distribution next to regions with 2-fold symmetry that form stable hairpin structures in the viral DNA strand.

Base Sequence↗
PubMed1978

Nucleotide sequence of bacteriophage fd DNA.

The sequence of the 6,408 nucleotides of bacteriophage fd DNA has been determined. This allows to deduce the exact organisation of the filamentous phage genome and provides easy access to DNA segments of known structure and function.

Base Sequence↗