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Biomedical subjects

K Richter

Publications and source records attributed to K Richter.

At least 289 records · Page 16Linked to original sources
PubMed1986

[Diagnostic contribution of endomyocardial biopsy in suspected latent cardiomyopathy].

Twenty-eight patients with suspected diagnosis of latent cardiomyopathy are reported. In all patients left ventricular endomyocardial biopsy (five or more specimens) was performed after noninvasive and invasive investigations. The indication to investigate invasively arose from clinical symptoms in combination with uncertain ECG disturbances. Coronary heart disease, latent myocarditis and latent cardiomyopathy were to be excluded. Hemodynamic parameters proved to be normal or borderline at rest. Angiocardiography and coronary angiography revealed no pathological findings. But in all cases the histological results of endomyocardial biopsy were characterized by pathological criteria as follows: inflammatory myocardial process, narrowing or obliterating diseases of intramural small arteries, exogenous-toxic myocardial disturbances, idiopathic cardiomyopathy, endomyocardial fibrosis with endocardial thrombus and infiltrations of eosinophiles. Four cases are demonstrated as examples.

Adult↗
PubMed1986

[Surgical treatment of patent ductus arteriosus Botalli in the premature infant. Indications and results of treatment].

125 preterm infants with persistent ductus arteriosus (PDA) had surgical ligation between November 1978 and December 1984. In an additional case the situation was complicated by severe coarctation, which had not been diagnosed prior to surgery. The mean birth weight was 1340 +/- 448 g (85 infants weighed less than 1500 g). Gestational age was 30.6 +/- 2.5 weeks. Age at surgical ligation was 13 +/- 7 days for all patients. Preterm infants from our hospital were operated on with a mean age of 9.5 days. Indications for surgical ligation were clinical and radiographic signs of large PDA, during the last two years supported by the results of pulsed doppler ultrasonography. Only one preterm infant with PDA and coarctation died intraoperatively. The overall results showed a mortality rate of 21.6%. This rate has decreased from 30.4 to 11.7% in the last year. Important improvement could be obtained by early ligation, with carefully maintained body temperature during surgery. Preoperative ventilation parameters were kept constant and changes in arterial blood pressure during operation were avoided. The percentage of permanent handicaps was lowered from 15.2 to 5.9% in the last year of our study. According to failure of indomethacin therapy in the very beginning of PDA treatment, it is our policy now to ligate PDA in preterm infants early and without delay by a trial with indomethacin therapy.

Ductus Arteriosus, Patent↗
PubMed1985

[Behavior of biochemical parameters in probands with suspect cardiovascular findings in relation to age and sex. Studies of a representative sample following roentgen image screening (the Berlin cardiac detection and monitoring model)].

Based on the high prevalence of cardiovascular diseases and the necessity of improved treatment, selected biochemical results from a complex follow-up examination after x-ray screening are presented. Significant differences (alpha less than or equal to 0.05) were found for LTT, cholesterol, glucose, uric acid and erythrocyte-sedimentation rate compared to a healthy control group. Furthermore, a significant age-dependent increase of creatinine as well as an age-dependent decrease of transaminases only in men were found. The results show the value of the x-ray screening method in persons with risk of cardiovascular disease characterized by morphologic x-ray findings, and can be referred to population.

Adolescent↗
PubMed1985

[Malignant melanomas of the vulva].

In 13 patients, mean age 57 (31-78) years, with malignant melanoma of the vulva, 7 of the tumors occurred on the Labia majora, 4 on the Labia minora and 2 on the clitoris. 8 cases involved nodular malignant melanomas, 2 cases each involved a superficial-spreading form and an acrolentiginous form, and one case involved a non-classifiable malignant melanoma. According to histological criteria 10 of 13 tumors showed a high risk of metastasising. At the time of diagnosis one of the patients was in stage II and one in stage III of the disease. Of the 13 patients, 6 died, as a result of the tumor, 5 within the first 2 years. The mean survival time was 15 (6-28) months. In three other cases the disease has reached an advanced stage: stage Ib, II or III. Up to now only 4 patients have remained symptom free, the symptom free interval averaging 62 (33-84) months. This investigation confirms the special characteristics of malignant melanomas of the vulva, which are the predominance of tumors having a bad prognosis and the rapidly progressing course of the disease.

Adult↗
PubMed1985

Biosynthesis of peptides in the skin of Xenopus laevis: isolation of novel peptides predicted from the sequence of cloned cDNAs.

From skin of Xenopus laevis, a few peptides have been isolated which are identical or homologous to gastrointestinal hormones and/or neurotransmitters of mammalian origin. We have studied the biosynthesis of these peptides using recombinant DNA techniques. From cDNA librariers constructed from skin mRNA, clones with inserts coding for the precursors of caerulein, thyrotropin releasing hormone and a new peptide termed PGLa have been isolated and sequenced. In the case of caerulein, a small family of precursors containing one, three or four copies of the end product have been detected. The caerulein sequences are separated by homologous sequences which potentially could give rise to additional constituents of skin secretion. Three such peptides have been detected which are presumably liberated from caerulein precursors by cleavage at single arginine residues.

Amino Acid Sequence↗
PubMed1985

Cell-free and cellular synthesis of chromogranin A and B of bovine adrenal medulla.

We have studied the cell-free and cellular synthesis of chromogranins A and B, two immunologically distinct protein families of adrenal chromaffin granules. Two cell-free systems (wheat germ and reticulocyte lysate) were used for translating messenger RNA isolated from bovine adrenal medulla. Two primary translation products could be immunoprecipitated in case of chromogranin A. In the presence of microsomes the two chromogranin A precursors (pre-chromogranins A) were converted into a single protein, apparently by the removal of different signal peptides. For chromogranin B only one precursor (pre-chromogranin B) was translated. In isolated chromaffin cells only one chromogranin A protein was synthesized which corresponded to the processed cell-free translation product. During prolonged incubation this protein became slightly larger and more acidic, probably due to glycosylation in the Golgi region. Chromogranin B is post-translationally converted to a significantly more acidic protein. It is concluded that proteolytic breakdown of newly synthesized chromogranin A and B in chromaffin granules is a slow process comparable to that of the enkephalin precursors. It is not yet known what function these chromogranins have and whether breakdown to smaller subunits is necessary for any function to evolve.

Adrenal Medulla↗
PubMed1985

[Anatomy of the visceral fascia of the pelvis from the didactic viewpoint].

The fascia-like formations of the pelvic subserosum are unsatisfactorily interpreted by the classical interpretations of "hypogastric gain" or "fibroglia". However, these two opposing concepts can be reconciled if the connective tissue of the female minor pelvis is not seen as a unit but rather as a complex structure. In the surroundings of the pathways directed towards, or originating from, the pelvic viscera, ontogenesis results in a densification of the at first very loose connective tissue and eventually in the formation of fascia-like structures. Hence, these are not primarily basic structures of the vessels and nerves, but originate wherever pathways are already present. Three "roads" lead from three roots in three planes to the inner genital. The road of the veins runs in a "transverse" plane ("horizontal" plane in the standing woman) to the lateral pelvic wall. This is responsible for the formation of the ligamentum cardinale which has been described as the central part of the "fibroglia". The arterial road runs craniocaudally in a "frontal" plane. The branches of the hypogastric artery (a. iliaca interna) have taken densified webs of fascia with them which produce the pattern of "hypogastric gain". The neurovegetative road originates at the sacrum at the foramina sacralia anteriora, and is in "sagittal" position. Loose connective tissue remains between the densification zones, and it is here where surgery can be performed practically without causing any trauma.

Arteries↗
PubMed1985

[Random sample size in ROC analyses].

ROC analysis has proved useful in assessing diagnostic efficiency. Large x-ray film series of thoracic images intended for cardiovascular diagnosis were used for studying diagnostic efficiency in relation to random sample size. Exploration of random samples from two classes of findings requiring diagnostic differentiation, with the same number of x-ray films in each class, showed satisfactory convergence between the radiologists' rating and the ROC curve if the size of the random sample groups was about 200 images each or larger. The smaller the random sample size (less than 200 images), the greater the scatter of the rating performance. In another series the rating ability of experienced radiologists was compared with that of a semi-automatic classificator. The semi-automatic classificator attained almost the same performance index as the low-performance evaluator.

Decision Theory↗
PubMed1985

[In vitro and in vivo studies of diclofenac suppositories in humans].

Five different preparations of diclofenac-suppositories (A, B, C, D, E) are investigated for in vitro liberation (modified paddle method) and for in vivo bioavailability in man (8-12 subjects) in a crossover design. In vitro, the time at which 63.2% of the drug are liberated (tL) is 14, 20, 25, 14 and 3.5 min for the preparations A, B, C, D and E, respectively. The steady state concentrations from the preparations B and C are 51 and 11%, respectively, and lower than for the others. In vivo, the time of the concentration maximum (tmax) in min is (mean +/- S mean): A = 68 +/- 18, B = 72 +/- 9, C = 120 +/- 22, D = 42 +/- 3, E = 24 +/- 0.5. The concentration maximum (cmax) in mumol . l-1 at tmax is (mean +/- S mean): A = 5.9 +/- 0.8, B = 3.9 +/- 0.3, C = 3.1 +/- 0.4, D = 5.7 +/- 0.6, and E = 5.5 +/- 0.8. The area under the curve (AUC) for all the preparations has found to be between 8.7 and 10,6 mumol . h . l-1. There is a significant correlation between the in vitro parameter tL and the in vivo data of tmax and cmax, respectively. In consequence, the invasion behaviour in vivo can be derived from in vitro data for drugs with similar good physicochemical properties as diclofenac-Na.

Biological Availability↗
PubMed1984

The predictive factor--a method to simplify Bayes' formula and its application to diagnostic procedures.

According to Bayes' rule the predictive value (PV) of a diagnostic test (= probability of disease if the test is positive) depends on the prevalence of the disease (= a priori probability), the sensitivity (c1) and the specificity (c2) of the test. A new variable has been introduced, the predictive factor (c), which is calculated as follows: c = c1/(c1 +1 -c2). Since the PV only depends on this factor and on the prevalence, the calculation is much easier and a general graphical solution is possible. This simplification renders several additional advantages and facilitates the understanding of the dependence of PV on prevalence.

Bayes Theorem↗
PubMed1984

Biosynthesis of thyrotropin releasing hormone in the skin of Xenopus laevis: partial sequence of the precursor deduced from cloned cDNA.

Skin of Xenopus laevis contains relatively large quantities of thyrotropin releasing hormone (TRH). Total mRNA isolated from skin was cloned in the plasmid pUC8. Among 1400 cDNA clones, one was found with an insert of 478 nucleotides coding for the amino-terminal part of prepro-TRH. This clone was detected using a mixture of two synthetic undecanucleotides for colony hybridization. The single open reading frame starts with a methionine residue and a stretch of hydrophobic amino acids, as is typical for signal peptides, and terminates at the poly(C) tail without a stop codon. The deduced polypeptide of 123 amino acids contains three copies of the sequences Lys-Arg-Gln-His-Pro-Gly-Lys Arg-Arg and a fourth incomplete copy at the carboxyl end. Typical pro-hormone processing at this sequence would yield pGlu-His-Pro.NH2,i.e. TRH. It is concluded that the cloned part of the mRNA codes for prepro-TRH and that the TRH precursor from skin of X. laevis is a polyprotein containing at least four copies of the end product in its amino acid sequence.

Amino Acid Sequence↗