Search PubMed⌕ Search

Biomedical subjects

A Beck

Publications and source records attributed to A Beck.

At least 181 records · Page 10Linked to original sources
PubMed1994

[Surgical secondary measures in unsuccessful prostaglandin treatment of tubal pregnancy].

As local drug treatment grew more common, the risk of persisting trophoblast remnants increased in tubal pregnancies treated in this way. We studied the secondary surgical measures in 52 patients, who had to undergo surgery for a second time after tubal pregnancy treated with prostaglandins. The indication for revision was arrived at 30 times on the basis of laboratory parameters (increasing or constant beta-HCG) (Group I). Reoperation had to be performed 22 times because of acute clinical symptoms (Group II). Laparotomy was performed 40 times, repelviscopy 12 times. In patients of Group I, the rate of rupture, that, had already occurred at the time of secondary surgery, was significantly smaller (p < 0.0001); in that case secondary surgery was significantly more often successful (p < 0.06) in preserving the tubes. In case of constant beta-HCG values 11 patients (50% of Group II) developed acute symptoms; another 7 patients (31.8%) also had to be reoperated on due to acute complaints, although the values were already clearly reduced. The study proves, that tubal pregnancies can be reoperated with preservation of the tubes even after unsuccessful prostaglandin therapy. The starting position for secondary surgery with preservation of the tubes is much better before acute clinical symptoms occur.

Adult↗
PubMed1994

[Effect of contralateral stimulation on otoacoustic evoked emissions in acute deafness].

23 patients with unilateral hearing loss and presence of TEOAE on both ears were examined with regard to the association between contralateral acoustic stimulation and evoked otoacoustic emissions. Contralateral white noise of 40 dB HL, 50 dB HL and 60 dB HL decreases the amplitude of TEOAE both at the ear with and without hearing loss. In comparison with a group of subjects with normal hearing, the decrease in the amplitude of TEOAE was less in the group of patients with hearing loss. Two paradoxical cases were found with an increase in the TEOAE amplitude in the ear with hearing loss during contralateral stimulation. It is assumed that impairment of the efferent synapses on the outer hair cells or of the decussated efferent nerve fibres at the floor of the fourth ventricle contributes to the pathogenesis of hearing loss. Impairment of the efferent system at brainstem level can explain the lower decrease in the amplitude both in the diseased ear and the normal ear. The behaviour of the normal ear during stimulation of the diseased ear can also be caused by disturbance of the afferent system.

Acoustic Stimulation↗
PubMed1994

Ultrasonography for evaluation of the carotid artery in head and neck cancer.

The dynamic relationship of lymph node metastases to surrounding vascular structures in the neck is important for preoperative patient assessment. When carotid artery involvement is suspected, this relationship often determines whether or not to operate. In the case of adhesive neck metastases along the internal jugular vein, it becomes possible to predict preoperatively if the integrity of this vein may be preserved. Ultrasonography has the ability to differentiate subtle from gross adherence, or simple compression from vascular invasion. This is done by manually palpating the tumor mass and asking the patient to perform various maneuvers while observing on a monitor the relationship of the tumor mass to the nearby artery. This article correlates the preoperative computed tomography/magnetic resonance imaging (CT/MRI) and ultrasound findings in 41 patients with large nodal metastases which were subsequently confirmed during surgery. In case of positive ultrasonographic invasion of the carotid artery, a transcranial Doppler ultrasonography (TCD) exam was performed to confirm adequate crossflow. Our experience with ultrasonography and TCD in patients with suspected involvement of the carotid artery shows reliable results and obviates in our hands the routine need for more complex, invasive, and expensive tests.

Carotid Arteries↗
PubMed1993

Neurotrophin induced cAMP and IP3 responses in PC12 cells. Different pathways.

NGF and BDNF elevate cAMP and IP3 levels in membranes of PC12 cells within a subsecond time period. The cAMP formation induced by NGF and BDNF pretreatment for 2 s was reduced by GDP-beta-S and PTX, but not the trkNGFR inhibitor K 252a. NGF, but not BDNF, induced IP3 formation. IP3 formation was reduced by K 252a, but not by GDP-beta-S and PTX. Using p75NGFR expressing, but trkNGFR-deficient PCNA cell membranes, NGF and BDNF induced cAMP formation, but not IP3 formation. We suggest that NGF and BDNF induced cAMP formation is mediated via a p75NGFR/G-protein mediated mechanism, and IP3 formation via a K 252a sensitive pathway.

Animals↗
PubMed1993

Differential expression of tomato (Lycopersicon esculentum L.) genes encoding shikimate pathway isoenzymes. I. 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase.

Tomato (Lycopersicon esculentum L. cv. UC82b) was found to contain two distinct 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase genes that are differentially expressed. The corresponding cDNAs were isolated and characterized. Both genes code for putative plastidic DAHP synthase isoforms. The deduced amino acid sequences are 79% identical. A comparison of the known Solanaceae DAHP synthases indicates two distinct conserved isoforms. The steady-state levels of transcripts of the two tomato genes differ in all organs analysed.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed1993

Radical lymphadenectomy in the primary carcinoma of the fallopian tube.

The primary carcinoma of the Fallopian tube is a highly aggressive tumor which can spread by the lymphatic route. The object of the present study was to evaluate the impact of radical pelvic and para-aortic lymphadenectomy on overall survival. Radical lymphadenectomy was performed on twelve patients in addition to hysterectomy and bilateral adnexectomy (group I). Twenty-eight patients subjected only to hysterectomy and adnexectomy formed the control group (group II). On average 47.6 lymph nodes were excised per patient. As long as the carcinoma was limited to adnexa and uterus (stages I and II), no lymph node metastases were found, only in stages III and IV were lymph node metastases detectable. Even though the median survival time of group I was considerably higher than of group II (43 versus 35 months), there was no statistically significant difference between the two groups (P < 0.65). Patients with stage III and stage IV disease had relatively longer median survival times if they had a lymphadenectomy. However, the difference was not statistically significant (P < 0.91). We cannot therefore recommend routine radical lymphadenectomy for primary Fallopian tube carcinoma. Whether or not lymph node dissection would lead to better results from rational selection of patient for adjuvant therapy is not known.

Fallopian Tube Neoplasms↗
PubMed1993

Influence of the length of the spacer on the partitioning properties of amphiphilic fluorescent membrane probes.

Four fluorescent diphenylhexatriene derivatives were considered as membrane probes, namely two ammonium compounds, 3-(diphenylhexatrienyl)propyltrimethylammonium (TMAP-DPH) and 22-(diphenylhexatrienyl)docosyltrimethylammonium (LcTMA-DPH), and two phospholipids, 1-palmitoyl-2-[3-(diphenylhexatrienyl)propanoyl]-sn-glyc ero-3-phosphocholine (DPHpPC) and 1-palmitoyl-2-[21-(diphenylhexatrienyl)henicosanoyl]-sn-phos phocholine (LcDPHpPC). For each pair, the molecules differ by the length of the polymethylenic spacer between the fluorescent moiety and the polar head, so one pair comprises two short chain molecules (C3 spacer) and the other two long chain molecules (C21 or C22 spacer). The partitioning of these probes between gel and liquid crystalline phases of multilamellar vesicles with binary composition (DEPC and DSPC) was measured by a method based on fluorescence anisotropy. The partitioning was shown to depend strongly on the length of the spacer. Short chain probes preferably partition into fluid phases (Kf/s = 1.7 +/- 0.3 for TMAP-DPH; 2.6 +/- 0.11 for DPHpPC), whereas long chain probes show a strong preferential partitioning for gel phases of the vesicles (Kf/s = 0.12 +/- 0.06 for LcTMA-DPH; 0.22 +/- 0.11 for LcDPHpPC). This strong partitioning may be explained by the interdigitation of the long polymethylenic chains across the mid-point of the lipid bilayer (I.E. Mehlhorn et al. (1988) Biochim. Biophys. Acta 939, 151-159), which is enhanced by the better packing provided by a gel phase.

Diphenylhexatriene↗
PubMed1993

Prognosis of rectal cancer in France.

We studied changes in the prognosis of cancer of the rectum (excluding the rectosigmoid junction) from 1978 to 1986 in the French department of Calvados on the basis of the 616 cases in the cancer registry. Taken as whole, survival has improved slightly with time (P < 0.01), but the improvement is only significant for men (P < 0.02), patients under 70 years (P < 0.01) and patients living in urban areas (P < 0.05). With regard to tumour characteristics, the improvement was significant only for patients with Dukes' stage C tumours at surgery (P < 0.02). To determine the reasons for the improvement in survival, the year of diagnosis and all other prognostic factors were studied in a multivariate model. Diagnostic conditions such as age and tumour stage did not vary from 1978 to 1986; in contrast, the rates of tumour resection and adjuvant radiation therapy increased, possibly explaining at least part of the improvement, particularly for patients with Dukes' stage C tumours.

Aged↗
PubMed1993

HER-2 and INT-2 amplification estimated by quantitative PCR in paraffin-embedded ovarian cancer tissue samples.

Competitive polymerase chain reaction (PCR) systems were developed for rapid and quantitative estimation of HER-2 (c-erbB-2) and INT-2 oncogene amplification in paraffin-embedded ovarian cancer tissue samples. The beta-globin gene was used as reference and DNA from paraffin-embedded placenta tissue as single copy control. Reliability of the PCR method could be demonstrated by comparing dot blot data with PCR data of identical tumour samples. The PCR method was used to determine HER-2 and INT-2 copy numbers in 196 ovarian cancer samples. HER-2 and INT-2 were found to be amplified in 40 and 19%, respectively. In 8% HER-2 copy numbers were greater than five, but no high INT-2 copies were noted. Kaplan-Meier estimates did not reveal significant association with overall survival. Indirect correlation between HER-2 and INT-2 amplification was observed. The present PCR system is a valuable method for prospective and retrospective studies.

Base Sequence↗
PubMed1993

Perinatal infections with Streptococcus pneumoniae.

Perinatal infections with Streptococcus pneumoniae although rare, have caused morbidity and mortality in both neonatal and puerperal patients. To determine the incidence of proven pneumococcal sepsis in these patient groups, blood culture records from 1977 to 1989 were reviewed. Of 89 parturient patients with true positive blood cultures, two (2.2%) were positive for the pneumococcus, whereas of 240 infants with positive blood cultures, three (1.25%) grew pneumococcus. The incidence of maternal pneumococcal sepsis was 0.04/1000 live births, and that of the neonates, 0.06/1000, and the overall rate for sepsis in these two groups was 1.7 and 4.7/1000 live births, respectively. In three mother-infant pairs, the identical pneumococcal serotypes, 7, 18, and 23, were isolated from both mother and infant. Birthweights and gestational ages of the infants ranged from 2330 to 3730 gm and 34 to 40 weeks, respectively. Respiratory distress and poor peripheral perfusion were the predominant clinical signs in the infants with sepsis and became apparent from shortly after birth until 5 days of life. Pyrexia, poor general condition, and leukocytosis characterized the mothers with sepsis. All patients survived following antibiotic and supportive care. Our epidemiologic survey confirms the rareness of perinatal pneumococcal infection and the ability of these organisms to cause morbidity in both mothers and infants.

Adult↗
PubMed1993

Neurotrophin induced second messenger responses in rat brain synaptosomes.

Neurotrophins (NGF, BDNF) elicit significant elevation of cAMP as well as IP3-concentrations in either membrane preparations or intact isolated nerve endings from rat brain hippocampus. The induced second messenger responses in membrane preparations were detectable in the subsecond time range. The IP3-level reached a maximum after a few hundred ms; whereas the cAMP-level continued to rise even after several seconds. The IP3-response but not the cAMP-signal was inhibited in the presence of the tyrosine kinase blocker K252a, suggesting that the two second messenger cascades were triggered via different mechanisms. The results suggest that neurotrophins may induce short-term effects in nerve terminals via second messenger pathways.

Animals↗
PubMed1993

The HIV-1 Nef protein shares an antigenic determinant with a T-cell surface protein.

OBJECTIVE: To characterize antigens on uninfected T lymphocytes reactive with monoclonal antibodies (MAb) directed against the HIV-1 Nef protein, and to search for antibodies directed against this epitope in HIV-1-infected individuals. DESIGN: Murine MAb directed against an epitope of Nef defined by amino acids 60-73 reacted with cell surface antigens of normal peripheral blood lymphocytes and permanent human T-cell lines. METHODS: The specificity of the MAb reaction was investigated by flow cytometry and immunofluorescence. The antigen was precipitated from lysates or uninfected cells using MAb or sera from HIV-1-infected individuals and analysed by Western blot and isoelectrofocusing. RESULTS: An antigen with an apparent relative molecular mass of 137,000 and an isoelectric point of 8.45 was immunoprecipitated with the cross-reactive MAb from uninfected human T cells. Sera from HIV-positive individuals recognizing a Nef epitope partially overlapping with the binding site of the cross-reactive MAb stained the 137 kD protein precipitated with the MAb in Western blot analysis, while HIV-positive sera without antibodies to this Nef region and sera from uninfected individuals were negative. CONCLUSION: The induction of autoantibodies cross-reactive with cellular surface proteins may play a role in the pathogenesis of AIDS.

Amino Acid Sequence↗
PubMed1993

Quantitative image analysis of vertebral body architecture--improved diagnosis in osteoporosis based on high-resolution computed tomography.

71 women, 64 post-menopausal, were examined by single-energy quantitative computed tomography (SEQCT) and by high-resolution computed tomography (HRCT) scans through the middle of lumbar vertebral bodies. Computer-assisted image analysis of the high-resolution images assessed trabecular morphometry of the vertebral spongiosa texture. Texture parameters differed in women with and without age-reduced bone density, and in the former group also in patients with and without vertebral fractures. Discriminating parameters were the total number, diameter and variance of trabecular and intertrabecular spaces as well as the trabecular surface (p < 0.05)). A texture index based on these statistically selected morphometric parameters identified a subgroup of patients suffering from fractures due to abnormal spongiosal architecture but with a bone mineral content not indicative for increased fracture risk. The combination of osteodensitometric and trabecular morphometry improves the diagnosis of osteoporosis and may contribute to the prediction of individual fracture risk.

Adolescent↗