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Biomedical subjects

G Engel

Publications and source records attributed to G Engel.

17 recordsLinked to original sources
PubMed1992

Elevated stromelysin-1 and reduced collagenase-IV expression in invasive rat embryo fibroblasts expressing E1A deletion mutants + T24-H-ras.

We have studied the in vitro invasive properties of 3 cell lines derived from the co-transfection of rat embryo fibroblasts (REF) with EIA genes deficient in exon 2 and T24-ras. All 3 cell lines showed invasive properties at passage 10 after isolation. Invasive cells expressed elevated levels of stromelysin-1 and reduced levels of 68-kDa type-IV collagenase compared with untransfected REF. In 2 cell lines the invasive capacity increased during in vitro propagation. The expression of stromelysin-1 increased during this process, whereas 68-kDa type-IV collagenase was persistently expressed at reduced levels. In the third clone analyzed, the invasive capacity decreased during culture, in parallel with decreased expression of stromelysin-1. The low level of stromelysin-1 expression observed in this cell line did not result from loss of AP-1-transcription-factor activity, and was not reversed by phorbol-ester treatment.

Adenovirus Early Proteins↗
PubMed1991

Heat resistance of ascospores of Byssochlamys nivea in milk and cream.

Byssochlamys nivea strains of rather varying origin used for heat inactivation experiments were cultured for 28 days at 30 degrees C on malt extract agar, since under these conditions the highest degree of heat resistance of the ascospores was observed. Inactivation was performed in steel capillary tubes to obtain reproducible results under experimental conditions comparable to those prevailing in practice. An inactivation temperature of 92 degrees C proved to be most practical. Decimal reduction times for the individual strains at this temperature in Ringer's solution varied between 1.3 and 2.4 s. In the temperature range studied, inactivation of ascospores in UHT milk (1.5% w/w fat content) and cream (10% w/w fat content) has not been found to differ significantly from that in Ringer's solution. Homogenization of milk as applied in practice did not affect heat inactivation of ascospores. Assuming the most unfavorable conditions (50 ascospores/l and using the most heat-resistant strain) the following relations between the level of infected 500 g packages were calculated: 1 of 10(6) packs infected; 24 s at 92 degrees C; 1 of 10(3) packs infected; 16.5 s at 92 degrees C; 1 of 10(2) packs infected, 14 s at 92 degrees C.

Animals↗
PubMed1991

Conservative management of a combined endodontic-orthodontic lesion.

Pulp injury may occur during orthodontic tooth movement particularly in previously traumatized teeth. Therefore the management of such cases requires specific therapeutic considerations. An extensive periradicular lesion was detected in an orthodontically treated maxillary incisor with an uncertain history of a previous traumatic incident. Conservative endodontic therapy resolved the periradicular lesion thus enabling the orthodontic treatment to continue uneventfully. It is essential to closely monitor the patients undergoing orthodontic treatment and those who are in retention, particularly if a history of trauma is suspected.

Adolescent↗
PubMed1987

[3H]ketanserin labels serotonin 5-HT2 and alpha 1-adrenergic receptors in human brain cortex.

The binding of [3H]ketanserin and [125I]BE 2254 [( beta-(4-hydroxyphenyl)ethylaminomethyl]tetralone) was characterized in human brain cortex membranes. As observed in saturation experiments, [3H]ketanserin (a reportedly selective serotonin 5-HT2 ligand) and [125I]BE 2254 (a selective alpha 1-adrenergic antagonists) labeled, apparently, a homogeneous class of high-affinity recognition sites. Competition experiments performed with [125I]BE 2254 and a series of 20 structurally different compounds resulted in steep and monophasic competition curves. In contrast, competition curves of these compounds for [3H]ketanserin binding were often shallow or biphasic, suggesting a heterogeneity of the sites labeled by [3H]ketanserin. In particular, alpha-adrenoceptor-selective ligands (e.g., prazosin, BE 2254, WB 4101, phentolamine) showed clearly biphasic curves displacing about 20% of [3H]ketanserin binding with nanomolar affinity. On the other hand, cinanserin, a selective 5-HT2 antagonist, showed nanomolar affinity for 80% of the sites labeled by [3H]ketanserin, and micromolar affinity for the other 20%. There was a highly significant correlation between [125I]BE 2254 binding and the minor component of [3H]ketanserin in human brain cortex membranes (r = 0.910, p less than 0.0001, n = 20). The data show that [3H]ketanserin binds in the nanomolar concentration range (1.5-1.8 nM) to both 5-HT2 and alpha 1-adrenergic receptors. Similar results were obtained in rat and pig brain membranes. The data suggest that ketanserin possesses a rather limited degree of selectivity in human tissue.

Binding, Competitive↗
PubMed1979

Acid phosphatase.

Acid phosphatase is a ubiquitous lysosomal enzyme that hydrolyses organic phosphates at an acid pH. Although the postpuberteral prostatic epithelial cell contains a uniquely high concentration of acid phosphatase, cellular components of bone, spleen, kidney, liver, intestine, and blood also contain this enzyme. The discovery that prostatic carcinoma cells often retain a high concentration of acid phosphatase characteristic of the normal postpubertal gland led to the recognition of the first clinically useful tumor marker. Recognition that the serum of patients with prostatic malignancy frequently contains an increased concentration of this enzyme has resulted in persistent efforts to identify the source, to accurately quantitate the level of serum acid phosphatase, and to determine the clinical significance of those levels. A variety of enzymatic and immunologic techniques have been employed to measure acid phosphatase. In the past, various substrates and inhibitors were utilized to increase specificity and sensitivity. Emphasis has now shifted to the development of radioimmunoassay and counterimmunoelectrophoresis in an attempt to enhance those parameters. Judgment of their efficacy awaits further testing and evaluation. The clinical significance of normal and abnormal serum acid phosphatase is constantly being reevaluated. In order to maximize the value of laboratory measurements, the clinical and pathologic status of the patient, the techniques employed in obtaining and storing the blood sample and the procedures used in analysis must be known and considered. Traditionally, the serum prostatic acid phosphatase has been thought to originate in the prostatic cancer cell and has been used to stage the disease. Until recently, elevated serum values have been accepted as an indication of extraprostatic disease, and were thought to rule out lesions confined to the prostate. The elevation of acid phosphatase levels in patients with disseminated disease or the failure of elevated levels to return to normal with treatment have been assumed to indicate a poor prognosis. However, unequivocal documentation of the validity of these statements is not available. Newer immunologic techniques for measuring acid phosphatase may significantly alter our current concept of its role as a tumor marker.

Acid Phosphatase↗
PubMed1978

Penile blood pressure in the evaluation of erectile impotence.

Identification of specific etiologies of erectile impotence is hindered by a paucity of objective criteria needed to segregate organic from psychogenic varieties and to define specific organic causes. Simplified measurement of penile blood pressure was performed with a digital cuff and a portable ultrasound Doppler system for flow detection. An index relating penile-to-brachial systolic blood pressure was generated, and the results were compared in patients with impotence versus patients with normal erections. The mean indices for the two groups were significantly different (P less than 0.05). The penile-to-brachial index provides an additional diagnostic tool in the evaluation of potency, allowing us to identify those patients with decreased penile blood flow, and may be helpful in selecting patients for revascularization procedures.

Blood Pressure↗
PubMed1978

Ureterolymphatic backflow.

A case is reported of apparent radiologic demonstration of a communication between a completely obstructed distal ureter and its draining lymphatics in a patient with invasive bladder tumor involving the ureteral orifice.

Aged↗
PubMed1977

[Investigations on the production of mycotoxins and their quantitative analysis. VI. Citreoviridin (author's transl)].

UV-densitometric and fluorodensitometric evaluations of the mycotoxin citreoviridin on thin-layer plates are described. The UV maximum is at 360 nm on thin-layer plates and at 388 nm in ethanolic solution. Its emission maximum has been found to be at 525 nm both in chloroform and on thin-layer plates. The two procedures are similar in their sensitivity. Since the UV-densitometric evaluation is more reliable, it is preferred to fluorodensitometric procedure.

Chromatography, Thin Layer↗
PubMed1975

[Investigations on the production of mycotoxins and their quantitative evaluation. I. The production of penicillic acid by Penicillium cyclopium (author's transl)].

A convenient thin-layer chromatographic screening procedure for the analysis of mycotoxins produced by Penicillium cyclopium is described. The production of penicillic acid is followed during a growth period of 44 days at two different temperatures. Quantitative evaluation is performed by UV densitometry at 234 nm. A biological profile is recorded showing the different ratios of four metabolites produced by Penicillium cyclopium and the definite effect of the growth temperature on the formation of penicillic acid in relation to the other metabolites.

Caproates↗
PubMedDate not supplied

Spiperone-induced endothelium-dependent relaxation of porcine coronary artery: an investigation into the underlying mechanism.

In pig coronary artery rings contracted by the thromboxane analogue U 46619 (9,11-dideoxy-11 alpha, 9 alpha-epoxy-methano-prostaglandin F 2 alpha), spiperone induced a relaxation which, at 30 mumol/l, corresponded to a complete reversal of the U 46619-induced contraction. The concentration-response curve for spiperone was bell-shaped. The second phase, i.e. the reduction of the relaxant effect (at concentrations above 30 mumol/l) was due to a contractile effect which was the only response in (1) endothelium-denuded arteries, (2) arteries treated with gossypol or methylene blue, or (3) arteries not precontracted with U 46619. Suramin and reactive blue 2 antagonized the relaxing effect, whereas metitepine, spiroxatrine, propranolol, idazoxan, flupenthixol, atropine and 8-phenyltheophylline did not. The endothelium-independent contraction was not reduced by metitepine. In strips of arteries with intact endothelium, incubated with [3H]adenosine and subsequently superfused with physiological salt solution containing dipyridamole, spiperone evoked an increase in tritium overflow above basal efflux. The present results are compatible with the hypothesis that spiperone releases ATP from the pig coronary artery. ATP, in turn, seems to activate endothelial P2 purinoceptors, leading to the release of endothelium-derived relaxing factor (NO) with a subsequent vascular relaxation.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗