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Biomedical subjects

T Beck

Publications and source records attributed to T Beck.

At least 109 records · Page 6Linked to original sources
PubMed1991

Listeria monocytogenes isolates can be classified into two major types according to the sequence of the listeriolysin gene.

The nucleotide sequence of a 3.5-kb BamHI fragment from Listeria monocytogenes 12067, a human clinical isolate of serotype 4b, has been determined. The DNA fragment harbors the gene for listeriolysin, part of the gene for a phosphatidylinositol-specific phospholipase C, and part of the gene for a metalloprotease. Comparison of the sequence with corresponding sequences from two other L. monocytogenes isolates revealed a significant number of nucleotide differences. Several of the differences give rise to amino acid substitutions. The most variable region was the examined part of the mpl gene, whereas the lisA gene showed a relatively high degree of conservation, particularly at the amino acid level. To analyze the pattern of sequence variability in the lisA gene, a 160-bp region covering nine nucleotide differences was sequenced from 36 isolates of different origins. This work showed that the strains can be grouped into two major types according to the nucleotide sequences. Oligonucleotide probing of a larger number of L. monocytogenes isolates showed that the observed differences can be used to subdivide the species. The data suggest a correspondence between the sequence type of the lisA gene and flagellar antigens. Assays based on hybridization or the polymerase chain reaction with type-specific oligonucleotides may provide fast and easy alternative methods for strain typing.

Amino Acid Sequence↗
PubMed1990

Failure of the lipid peroxidation inhibitor U74006F to improve neurological outcome after transient forebrain ischemia in the rat.

The lipid peroxidation inhibitor U74006F (21-[4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl-16-methylp regna- 1,4,9 (11)-triene-3, 20-dione) was tested for cerebroprotective properties in the rat. Transient forebrain ischemia was induced by occlusion of the carotid arteries and simultaneous lowering of the blood pressure to 40 mmHg. Repetitive doses of 10 mg/kg U74006F were administered intraperitoneally 10 min before and again 30 min and 24 h after the transient forebrain ischemia. U74006F did not significantly improve histological outcome in this model, suggesting lipid peroxidation to be a minor determinant for the neurological outcome under these experimental conditions.

Animals↗
PubMed1990

Postischemic glucose utilization in rat hippocampal layers.

The influence on hippocampal glucose utilization was determined in male Wistar rats 7 days after a 10-min forebrain ischemia. Ischemia was induced by clamping of the carotid arteries and lowering blood pressure to 40 mm Hg. Despite severe neuronal damage as assessed by histological techniques, local cerebral glucose utilization (LCGU) was significantly increased in the pyramidal and radiatum layer of the CA1 sector, while in layers of the CA2, CA3 and CA4 sector and dentate gyrus. LCGU was reduced compared to non-ischemic controls. The increases in LCGU are suggested to reflect long-lasting hyperexcitation in the selectively vulnerable CA1 sector, implicating a correlation between cellular hypermetabolism and neuronal damage.

Animals↗
PubMed1990

Glucose utilization in rat hippocampus after long-term recovery from ischemia.

The influence on hippocampal glucose utilization of a transient 10-min forebrain ischemia was quantified in male Wistar rats after 2 and 3 weeks as well as after 3 months by application of the [14C]2-deoxyglucose technique. Ischemia was induced by occlusion of the carotid arteries and simultaneous lowering of the blood pressure to 40 mm Hg. For identification of the hippocampal architecture, sections were stained for perikarya (cresyl violet) and for acetylcholinesterase. The hippocampal regions clearly showed different responses to the ischemic insult. The necrotic pyramidal cells being almost completely removed, significant increases in glucose utilization occurred in most layers of the CA1 sector at 2 and 3 weeks post ischemia, while widespread reductions prevailed in all other sectors and the dentate gyrus. At 3 months after the ischemic insult, glucose utilization was reduced in all hippocampal structures including the CA1 region. The increases in glucose utilization in the CA1 sector are suggested to indicate long-lasting presynaptic hyperexcitation, while the widespread reductions in glucose utilization demonstrate that neuronal activity is also altered in hippocampal areas that do not show major histological damage.

Animals↗
PubMed1990

[Results of surgical treatment of vulvar cancer].

129 patients with carcinoma of the vulva were treated at the Dept. of Obstetrics and Gynaecology from 1966-1985. FIGO stage I was observed in 21% of the cases, FIGO stage II in 50%, FIGO stage III in 10% and FIGO stage IV in 8% of the patients. In 10% of the patients, definite classification was not possible. Mean age at the onset of the disease was 66.2 years, the mean time of observation 63 months. Kraurosis of the vulva or leukoplakia were simultaneous phenomena recorded locally in 67% of the patients. Histological investigation showed squamous cell carcinoma in 93% of the cases. The tumours were most frequently observed on the labia and the clitoris. 98% of the patients underwent surgery, 64% radical vulvectomy with inguinal lymph node disection. 56% of the patients of this group had a 5-year survival rate, which was 47% for the entire group of patients. Wound healing disorders were the most frequently observed postoperative complications. Metastasis to the inguinal lymph nodes at the time of diagnosis is the critical point of the prognosis. In the absence of lymph node involvement, 68% of the patients achieved a 5-year survival, in the presence of lymph node involvement, the 5-year survival rate was only 13%. Results obtained by this study support the view, that radical surgery at the earliest possible time is the treatment of choice for carcinoma of the vulva.

Adult↗
PubMed1990

[Significance of neu-protein for prognosis of breast cancers].

In 147 primary breast carcinomas, over-expression of NEU-protein was detected immuno-histochemically. 20 tumours (13.6%) showed a positive reaction. Correlations with established prognostic factors, showed a significant relationship to unfavourable histological grading and negative oestrogen receptor status, as well as to the negative status of both oestrogen and progesterone receptors. However, no correlation could be demonstrated with the progesterone receptor alone. Only a trend without significance was demonstrated to the tumour size and proliferation rate-indicated by the Ki-67 antibody. No correlation existed to the status of the axillary nodes. Overexpression of NEU-protein proved to have a significant influence on the disease-free survival and overall survival in a median follow-up time of 31 months. Nevertheless, this could be shown only for tumours with metastasis in axillary nodes, but not for nodal negative tumours. A possible Longer follow-up time is necessary, to show a difference of results for the latter group.

Biomarkers, Tumor↗
PubMed1990

[Clinical follow-up studies on the prognostic significance of immunohistochemical estrogen receptor determination of breast cancer].

We investigated the oestrogen-receptor content (ER-ICA) of 614 tissue samples taken from breast carcinomas (all obtained from patients at the Universitäts-Frauenklinik, Mainz FRG) using immunohistochemical procedures. Since the findings of follow-up studies as well as estimates of survival probability (according to the procedure of Kaplan-Meier) for 334 of the primary breast carcinomas were available, it was possible, to assess the prognostic value of the immunohistochemical results. The percentage of receptor-positive tumour cell nuclei (i.e. the heterogeneity of the tumour), as opposed to the staining intensity, proved to be the most useful criterion of the IRS, whose cut off level was determined as being IRS 1. Regardless of their lymph node status, mammary carcinomas which were immunohistochemically positive for estrogen receptors, were found to have a significantly better short-term prognosis, than breast tumours which were negative for such receptors. In the case of certain breast carcinomas exhibiting contradictory findings (i.e. ER-ICA positive but biochemically negative for oestrogen receptors), the present immunohistochemical method provided the most accurate assessment of the biological behaviour and development of the tumor. Therefore, ER-ICA represents a valuable prognostic criterion, which when complemented with PR-ICA, should facilitate attaining optimal selection of patients suitable for endocrine therapy.

Adult↗
PubMed1990

[Does vascularization of the fetal placenta modify end-diastolic blood flow velocity in umbilical arteries? A histometric contribution to the validation of Doppler ultrasound].

The foetal intravillous blood volume was approximately determined in 90 cases, using placental histiometry post partum. This was compared with the Doppler sonographic flow patterns in the umbilical arteries determined during the last week ante partum. A direct dependence was seen: The larger the peripheral vascular tree of the placenta fetalis, the lower the resistance against the blood flow in the umbilical artery, i.e. the higher the enddiastolic blood flow velocities and vice versa. There is a highly significant correlation between the foetal intravillous blood volume and the foetal risks of Caesarean section performed, because of intrauterine asphyxia, growth retardation or reduced foetal outcome.

Asphyxia Neonatorum↗
PubMed1989

Morphine-induced alterations of local cerebral glucose utilization in the basal ganglia of rats.

The actions of various doses of morphine on the local cerebral glucose utilization (LCGU) were studied by means of the autoradiographic [14C]2-deoxyglucose technique. Morphine (1-15 mg/kg i.p.) decreased LCGU in most areas of the basal ganglia (caudate nucleus, globus pallidus, nucleus accumbens), but not in the substantia nigra pars compacta. LCGU was also decreased in limbic nuclei, such as septum, hippocampus and amygdala, and in most thalamic areas. In most cortical regions, a decrease was found as well. Findings in some efferent nuclei seemed of particular interest, namely in the substantia nigra pars reticulata, anteroventral and lateral nucleus of the thalamus and the subthalamic nucleus, where decreases in LCGU were found after administration of 7.5 mg/kg or sometimes lower doses, but not after 15 mg/kg of morphine. The decreases seem to reflect a general depressory effect of morphine on neuronal activity which is known from electrophysiological studies. Part of these effects might be, in addition, due to an activation of dopaminergic neurons, since dopamine mainly acts as an inhibitory neurotransmitter. This dopaminergic activation leads to characteristic behavioral effects after lower doses of morphine. The largest dose used (15 mg/kg) produces muscular rigidity, probably by a direct action on the striatum. This effect antagonizes and masks the dopaminomimetic effects. The results suggest that it also antagonizes the functional alterations in some efferent nuclei of the basal ganglia manifest after lower doses of morphine. Local injections of morphine (15 micrograms) led to decreases of LCGU in the various parts of the striatum, but to increases in lateral and anteroventral thalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Different metabolic changes in the lateral geniculate nucleus and the superior colliculus of adult rats after simultaneous or delayed double enucleation.

By means of the [14C]deoxyglucose method the local cerebral glucose utilization (LCGU) was measured in the lateral geniculate nucleus and the superior colliculus of rats with a simultaneous double enucleation, animals with an enucleation of the right eye between neonatal and adult stages followed by an enucleation of the left eye some months later and adult control rats. The control animals show LCGU values within the limits published by other observers. The LCGU values of the simultaneously double-enucleated rats are reduced on both sides to the same extent by about 20%. The dorsal lateral geniculate nucleus shows the largest decrease. The LCGU values of the rats with the delayed double enucleation have decreased even more (up to 37%). The right sided visual brain regions have a significantly lower LCGU than the corresponding regions on the left side. These findings indicate that unilateral enucleation from neonatal to adult stages leads to adaptive changes resulting in a higher metabolic vulnerability, which is revealed by the second enucleation.

Aging↗
PubMed1989

Local cerebral glucose utilization in the autoimmune New Zealand black (NZB) mouse.

By means of the [14C]-2-deoxyglucose method the local cerebral glucose utilization (LCGU) was measured in 41 brain regions in autoimmune New Zealand Black (NZB) mice and in Carworth Farm Winkelmann (CFW) mice, which served as the control strain. At the age of 6 months, the mean LCGU of all measured areas and brain stem nuclei was 67.7 mumol glucose/(100 g x min) in the nonautoimmune CFW mice. These LCGU values are within the limits published by other observers. In contrast, in the aged-matched NZB mice the glucose use was markedly reduced, the mean LCGU of all measured areas being 37.7 mumol glucose/(100 g x min). These findings suggest that the immunological, morphological and behavioural abnormalities in the aged NZB mouse correlate with a reduced functional activity of the central nervous system, measured as reduced cerebral glucose utilization.

Animals↗
PubMed1989

[The immunohistochemical growth fraction (Ki-67) of breast cancers: relations to tumor spread, tumor morphology and receptor testing].

245 breast cancer tissues were analysed immunohistochemically, using monoclonal antibody Ki-67, which spezifically reacts with a nuclear antigen of proliferating cells and represents the so-called growth fraction. According to the number of positive cells, three Ki-score categories (I-III) were established. The results were compared with prognostic variables (Histological grading, DNA-cytophotometry), staging parameters, immunocytochemical (ER-ICA, mPRI), and biochemical (DCC) hormone receptor assay. We found a good correlation between Ki-67 and grading (Bloom and Richardson): G 1-tumors had small growth fractions, in contrast to G-III carcinoma, which showed a high percentage of Ki-Score III. Receptor negative cases had a large growth fraction and receptorpositive ones showed an uniform distribution. The comparison between Ki-67 and tumor spread or DNA-Cytophotometry showed no correlation. The majority of 31 recurrent tumors not only had a large number of positive cells, but also a definite dependence was found between Ki-Score and length of the disease-free period. Ki-67 seems to be an important immunohistochemical marker of breast cancer, which contributes to the individual assessment of the disease and can possibly give predictions on tumor development and response to radiation and systemic therapy.

Adult↗
PubMed1989

[Results of surgical treatment of stage IIb cervix cancer].

A total of 506 cases of cervix cancer, Stage Ib and IIb, operated according to Wertheim-Meigs were retrospectively (1972-1986) evaluated with their clinical and morphological aspects. After 1978 a more intensive histological evaluation of the specimen was performed, resulting in the examination of a large number of pelvic lymph nodes. The amount of lymph nodes infiltrated depends on tumour stage, invasion depth, regional lymphovascular invasion of the tumour edge and parametria, and on haemangiosis carcinomatosa. Stage pT2b cervical cancers survived five years in 81% of cases, when lymph nodes were not involved--in 69% (1-3 infiltrated l.n.) and 64% (3 infiltrated l.n.) of cases with positive lymph nodes. The five-year survival rates were further determined by the parametrial infiltration and the number of positive pelvic lymph nodes. If neither the parametria nor the lymph nodes are infiltrated by the tumor the survival rate is 96% whereas in cases of lymphovascular invasion of the parametria without infiltrated lymph nodes the rate decreases to 79%; in cases in tumor infiltration of both lymph nodes and parametria the cure rates are worst (62%). The operation of cervical cancer of Stages Ib and IIb with a thorough histological evaluation of the excised tissue therefore has a high prognostic value, but it also probably has better cure rates than is the case with radiological treatment.

Adult↗
PubMed1989

[Pulsed Doppler sonography of the umbilical artery and fetoplacental resistance. A histometric study of gestosis placentas in comparison with a normal sample].

Histometric data from placentas after EPH gestosis, in cases with normal (n = 15) or pathological (n = 13) foetal umbilical artery flow velocity wave forms, are compared with data from uncomplicated pregnancies (n = 17). The cross-sectional areas of the villi were increased in both gestosis groups, whereas the diffusion capacity, the degree of vascularisation, the foetal placental blood volume and the length of epithelial plates and their quota of the circumference of the villi are decreased only in cases of gestosis with pathological flow velocity wave forms. In this group a high rate of caesarean sections for foetal distress was necessary and the foetal outcome was poor. We were able to prove the possibility of estimation of "placental risk" with pulsed Doppler ultrasound of an umbilical artery with morphometric data.

Asphyxia Neonatorum↗