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Biomedical subjects

B Betz

Publications and source records attributed to B Betz.

At least 19 recordsLinked to original sources
PubMed2006

Aberrant methylation of the Wnt antagonist SFRP1 in breast cancer is associated with unfavourable prognosis.

The canonical Wnt signalling pathway plays a key role during embryogenesis and defects in this pathway have been implicated in the pathogenesis of various types of tumours, including breast cancer. The gene for secreted frizzled-related protein 1 (SFRP1) encodes a soluble Wnt antagonist and is located in a chromosomal region (8p22-p12) that is often deleted in breast cancer. In colon, lung, bladder and ovarian cancer SFRP1 expression is frequently inactivated by promoter methylation. We have previously shown that loss of SFRP1 protein expression is a common event in breast tumours that is associated with poor overall survival in patients with early breast cancer. To investigate the cause of SFRP1 loss in breast cancer, we performed mutation, methylation and expression analysis in human primary breast tumours and breast cell lines. No SFRP1 gene mutations were detected. However, promoter methylation of SFRP1 was frequently observed in both primary breast cancer (61%, n=130) and cell lines analysed by methylation-specific polymerase chain reaction (MSP). We found a tight correlation (P<0.001) between methylation and loss of SFRP1 expression in primary breast cancer tissue. SFRP1 expression was restored after treatment of tumour cell lines with the demethylating agent 5-aza-2'-deoxycytidine. Most interestingly, SFRP1 promoter methylation was an independent factor for adverse patient survival in Kaplan-Meier analysis. Our results indicate that promoter hypermethylation is the predominant mechanism of SFRP1 gene silencing in human breast cancer and that SFRP1 gene inactivation in breast cancer is associated with unfavourable prognosis.

Adult↗
PubMed2001

Resistance to CD95-mediated apoptosis in breast cancer is not due to somatic mutation of the CD95 gene.

Resistance to CD95 (Apo-1/Fas)-mediated apoptosis is a typical feature of breast cancer cells. Recent studies identified deleterious mutations of the CD95 gene not only in a variety of B cell lymphomas but also in a number of solid tumor entities. Therefore, we amplified and sequenced selected regions of the CD95 gene from 48 breast cancer cases and 10 cell lines but no mutation was found. In the presence of both polymorphic alleles, loss of heterozygosity was excluded in 27 informative cases. We conclude, that relevant somatic mutations of the CD95 gene occur, if at all, at a low frequency and are not the primary cause for resistance to CD95-mediated apoptosis in breast cancer.

Apoptosis↗
PubMed2000

The Satz-Mogel short form of the Wechsler Adult Intelligence Scale--revised: effects of global mental status and age on test-retest reliability.

Abbreviated versions of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) have been developed as time saving devices that provide accurate estimates of overall level of general intellectual functioning while decreasing test administration time. The Satz-Mogel short form of the WAIS-R has received substantial attention in the literature as an accurate measure of intellectual functions when compared with the Full WAIS-R. However, most studies comparing the Satz-Mogel version to the Full WAIS-R have only provided correlational analyses. Our study was an attempt to apply a more rigorous statistical methodology in determining if the Full WAIS-R and abbreviated versions are equivalent. We explored the impact of level of global mental status and age on the Satz-Mogel version. Although the two forms of the test correlated highly, repeated measures design indicated significant differences between Satz-Mogel and Full WAIS-R when participants were divided into groups based on level of global impairment and age. Our results suggest that the Satz-Mogel version of the test may not be equivalent to the full WAIS-R and is likely to misrepresent a patient's level of intellectual functioning, particularly for patients with progressive degenerative conditions. The implications of applying Satz-Mogel scoring to the Wechsler Adult Intelligence Scale-III (WAIS-III) are discussed.

Age Factors↗
PubMed1999

CD95 ligand expression in dedifferentiated breast cancer.

CD95 ligand expression has been observed in various malignancies. Studying the CD95 ligand (CD95L) and receptor (CD95) system in eight non-malignant mammary tissues and 40 breast cancer tissues, mRNA and protein expression was determined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence. mRNA levels of CD95L correlated positively (r=0.90; p< 0.01) and transmembrane CD95 inversely (r=-0.88; p< 0.01) with histopathological grading of the breast tumours: CD95L mRNA levels were low in adenomas, but increased by 20-fold in grade I, 120-fold in grade II, and 310-fold in grade III breast cancer. In contrast, CD95 mRNA levels were low in high-grade carcinomas, but high in benign mammary tissues. Since CD95L acts as an efficient inducer of apoptosis in CD95(+) cells, apoptotic cells were identified on the tissue sections. Tumour-infiltrating lymphocytes and stromal cells in close proximity to CD95L-expressing breast cancer underwent apoptosis. As a functional test, CD95(+) target cells were cultured on breast cancer tissue sections. The target cells underwent apoptosis when cultured on breast cancer sections, but could be rescued when CD95L was specifically blocked by a CD95-Fc fusion molecule. The data suggest an inverse regulation of CD95 ligand and receptor expression during dedifferentiation of breast cancer. Killing of bystander cells by the CD95L-expressing breast tumour could be involved in tissue invasion.

Adult↗
PubMed1997

Resolution of subependymal cysts in neonatal holocarboxylase synthetase deficiency.

Holocarboxylase synthetase deficiency is typically a biotin responsive disorder that presents with lactic acidosis, tachypnea, temperature instability, and shock in neonates (Briones et al.1989 and Fuchshuber et al. 1992). The primary defect in cases studied to date appears to be the decreased affinity of HCS for its substrate, biotin (Gompertz et al. 1971). Supplemental biotin can provide sufficient substrate to increase HCS enzymatic function and thereby permit biotinylation of the four carboxylase apoenzymes (Briones et al. 1989). We report an infant with HCS deficiency who presented with lactic acidosis, shock, and hypertonia. Subependymal cysts were identified on cranial ultrasound and subsequently confirmed by MRI. Six months following biotin supplementation, she is developmentally normal and MRI of the brain shows complete resolution of the cysts.

Biotin↗
PubMed1996

Head injury in a college population: analysis of epidemiological factors.

Head injuries are frequent occurrences, and the majority are considered mild Most epidemiological studies have used hospitalized cases, and, as a result, those who sustain a head injury but do not receive intensive medical attention are not considered It can be assumed that those not receiving medical attention most likely sustained mild head injuries A few researchers have examined self-reported head injury, but the data is still limited Little is known about those individuals who incur head trauma and resume normal functioning without treatment The purpose of this study was to identify and describe the epidemiological correlates of head injury within a young high functioning population The present study examined head injury and its associated factors in a college sample, which included such areas as demographics, nature of head injury, and prevalence of postconcussion symptoms.

Journal Article↗
PubMed1990

[Respiratory tract diseases in oyster mushroom cultivators].

Oyster mushrooms are cultivated for human consumption in various subspecies. Their spores are a highly potent allergen, causing an exogenous allergic alveolitis. Relevant early pointers are the typical anamnesis, reduced vital capacity without any signs of obstruction, slight changes on x-ray film, positive immunofluorescence test. Frequent and typical wrong diagnoses during the initial episodes of the disease are: respiratory infection, influenza, pleuritis, type I allergy. So far, antibodies were identified in 76 immunofluorescence tests performed in 98 exposed subjects; 29 of these demonstrated signs of disease. Antibody formation is definitely subspecies-specific. Doubtful cases of "habituation" or negative antibody levels can be explained by a change in subspecies cultivation and hence a different antigen spectrum. The only therapeutically effective method is active prevention at the place of work as well as avoidance or elimination of the causative allergen. Drug treatment is useless. The only effective measure is to certify temporary disability to keep the patient away from the allergen.

Basidiomycota↗
PubMed1977

Messenger RNA-controlled Increase of Phenylalanine Ammonia-Lyase Activity in Parsley: Light-Independent Induction by Dilution of Cell Suspension Cultures into Water.

A specific antiserum, raised against purified phenylalanine ammonialyase from irradiated cell suspension cultures of parsley (Petroselinum hortense Hoffm.), was used to compare the enzyme species induced either by dilution or by irradiation of the cell suspensions, to investigate the effect of dilution on the rate of synthesis of the enzyme protein in vivo, and to analyze the changes in specific activity of polyribosomal mRNA for the enzyme subunits in vitro. The mRNA activity in vitro was measured by translation of the polyribosomal RNA in a rabbit reticulocyte lysate.The results of immunodiffusion assays indicated that dilution and irradiation of the cell suspensions induced immunologically identical molecular species of phenylalanine ammonia-lyase. Dilution resulted in a large but short term increase in the rate of synthesis of the enzyme. Highest rates of synthesis were reached after 5 to 6 hours, and were followed by a rapid decline. The curves obtained for the changes in the rate of enzyme synthesis, both in vivo and in vitro, coincided with the curve for changes in the rate of appearance of catalytically active enzyme, as calculated from the observed changes in enzyme activity. These results suggested that the changes in enzyme activity were caused by corresponding changes in the amount of enzyme-specific polyribosomal mRNA.The dilution of cell cultures had no significant effect on the total rate of incorporation of radioactivity into protein in vivo or on the general template activity of the polyribosomal RNA in vitro throughout at least 25 hours.

Journal Article↗
PubMed1976

Light-induced enzyme synthesis in cell suspension cultures of Petroselinum hortense. Demonstration in a heterologous cell-free system of rapid changes in the rate of phenylalanine ammonia-lyase synthesis.

The conditions for protein synthesis in vitro with polyribosomes from cell suspension cultures of parsel (Petroselinum hortense) and a wheat-germ extract were investigated. Two different criteria were used as estimated of the translational activity: (a) the total rate of incorporation of [35S]methionine into acid-insoluble material; (b) the ratio of large (molecular weight greater than 25000) to small (molecular weight less than 25000) peptide products. Depending on which of the criteria was employed, the pH optimum and the optimal concentrations for Tris=acetate, magnesium acetate, KCL, methionine and the wheat-germ extract differed considerably. The translational activity of the polyribosomes (both criteria) was effciently protected by 0.1 M Mg2+ against degradation during the isolation procedure. The rate of synthesis of phenylalanine ammonia-lyase in vitro with the polyribosomes was determined by measuring the incorporation rate of L-[35S]methionine into protein which was precipitable by a rabbit antiserum prepared for the purified enzyme. The immunoprecipitate was analyzed by disc gel electrophoresis in the presence of dodecylsulfate and was shown to contain small amounts of the complete enzyme subunits and relatively large amounts of shorter peptides which were also characteristic for the enzyme. The time course of light-induced changes in the rate of phenylalanine ammonia-lyase synthesis in vitro were investigated during a period of 15 h under two different conditions of induction: the cell cultures were irradiated with ultraviolet light eith (A) continuously or (B) for 2.5 h and then returned to darkness. Although the highest rate of enzyme synthesis was observed somewhat later inexperiment A than in experiment B, the periods of time during which the rate of synthesis increased rapidly were limited in both cases to only a few hours. The results obtained in vitro were identical within the limits of the experimental error with theoretical calculations of the changes in the rate constant of phenylalanine ammonia-lyase synthesis in vivo. These changes were calculated from the corresponding curves for the changes in the enzyme activity under the conditions of induction. The results are in agreement with previous observations suggesting that the induction of phenylalanine ammonia-lyase by light in the parsley cells was a short-term effect whose efficiency was greatly reduced within the 15 h of experimentation, even under continuous irradiation.

Ammonia-Lyases↗