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Biomedical subjects

T Weber

Publications and source records attributed to T Weber.

At least 253 records · Page 14Linked to original sources
PubMed1994

Cytokine mRNA levels in mononuclear blood cells from patients with multiple sclerosis.

We determined the cytokine messenger RNA (mRNA) expression pattern of blood mononuclear cells in 45 patients with the relapsing-remitting form of MS and 32 patients with other neurologic diseases. Using a semiquantitative polymerase chain reaction method, we detected significantly higher levels of tumor necrosis factor-alpha and lymphotoxin mRNA in patients with relapsing compared to those with stable disease (p < 0.001), but transforming growth factor-beta and interleukin-10 mRNA expressions were higher in patients with stable disease.

Cytokines↗
PubMed1994

FUNCTION OF THE TENSOR MUSCLE IN THE CICADA TIBICEN LINNEI

The calling song and the disturbance squawk of the cicada Tibicen linnei (Insecta: Homoptera) are described in terms of their physical parameters. The calling song is composed of quiet parts, which are very similar to the disturbance squawk, and loud parts, which are amplitude- and rate-modulated. The role of the tensor muscle acting on the tymbal frame in modulating the sound pulse amplitude was investigated. We demonstrate by tensor nerve recordings, by mechanical mimicking of the tensor muscle action and by electrical stimulation of the tensor nerve, that the contraction of the tensor muscle is responsible for (a) initiating sound production and (b) modulating the sound pulse amplitude. These results allow us to construct a model which suggests that the tensor shifts the tymbal into a mechanical working range that enables sound production and modulation of the sound pulse amplitude.

Journal Article↗
PubMed1994

AUDITORY THRESHOLD CHANGE IN SINGING CICADAS

The hearing sensitivity in singing cicadas is reduced during sound production by a folding of the tympanal membranes. Using electrophysiological recording and nerve stimulation techniques, we have shown an effect of the folded tympanum on the auditory threshold of two species of cicadas, Tibicen linnei and Okanagana rimosa. Auditory thresholds of both species increased by about 20 dB when the tympana folded during singing. In T. linnei the increase in threshold affected the whole frequency range, from 1 to 16 kHz, in a similar way. Electrical stimulation of one or both auditory nerves resulted in a folding of both tympanal membranes in a way very similar to that seen in singing animals. We have demonstrated that a cicada male is able to adjust its auditory threshold within a range of about 20 dB by the tympanal folding mechanism.

Journal Article↗
PubMed1994

Technology use, cesarean section rates, and perinatal mortality at Danish maternity wards.

Fifty-eight Danish maternity units, managing 99% of Danish deliveries, participated in a cross sectional study to assess the relationship between use of birth-related technologies, cesarean section rates and perinatal mortality for births after 35 completed weeks of gestation. A regional technology index (0-10) was calculated for each maternity unit according to its use of ante and intra partum fetal heart rate monitoring (FHM), hormone analysis (human placental lactogen (HPL) and/or estriol (O3)), fetal blood samples (scalp-pH), intrauterine catheter and umbilical cord-pH. Maternity units using FHM had a 15% higher cesarean section rate (not planned) than units not using FHM (p < 0.05). The referral of potentially complicated deliveries to central units, which at the same time relatively often use FHM, is probably responsible for this association. Trying to encounter this selection bias a technology index was calculated for eight regions in Denmark, weighting the index of each unit in a region according to its number of deliveries. There was no association between the technology index in these eight regions in Denmark and their cesarean section rates. Use of FHM, technology index, and unplanned cesarean section rates in the eight regions were all without significant association to the perinatal mortality in the same regions. For births after the 35th completed week of gestation, this study could not confirm a relationship between different degrees of use of birth-related technologies and perinatal mortality.

Adult↗
PubMed1994

Automated and manual serum free thyroxine assays evaluated with equilibrium dialysis.

Two fully automated serum FT4 assays (Ciba Corning: ACS-180; Abbott Diagnostics: IMx) and two manual/semiautomated assays (Wallac: Delfia; Diagnostic Products Corp.: Coat-A-Count) were compared with a FT4 reference method based on equilibrium dialysis (ED) using routine clinical samples (n = 105-150). For the full range of FT4 concentrations the correlation with ED was good (r = 0.932-0.959), except for Coat-A-Count (r = 0.852), a single-step analogue-type method. Analytical inaccuracy of the automated methods at low FT4 concentrations was revealed by the differential plot: the IMx assay overestimated concentrations < 10 pmol l-1 and the ACS-180 assay concentrations < 6 pmol l-1. The between-assay CVs for the automated methods were not better than for the non-automated assays indicating problems of calibration curve stability for the automated assays.

Autoanalysis↗
PubMed1994

[Clinical observations on Stewart-Treves syndrome].

Adding to the existing literature three cases of Stewart-Treves-syndrome in a secondary lymphedema of the leg, a postmastectomy lymphedema with progressing mamma-ca and an uncomplicated postmastectomy lymphedema are described and compared with former observation. Thanks to the physical therapy of edema the frequency of Stewart-Treves-syndrome seems to be lowered compared to former statistics.

Aged↗
PubMed1993

[T/QRS-ratio and cardiotocographic changes in the second stage of labor--related to fetal condition at delivery].

The T/QRS ratio of the foetal electrocardiogram (ECG) was recorded from 92 women in labour. Recordings to within 30 min of delivery from 55 women were available for analysis. There was a weak but statistically significant correlation between increasing mean T/QRS ratio and increasing pH/standard base excess (SBE) in the umbilical artery of the 55 foetuses (Spearman, respectively r = 0.28, p = 0.04 and r = 0.29, p = 0.04); the corresponding numbers for the subgroup of 22 where the cardiotocogram was classified as normal being respectively r = 0.51, p = 0.02 and r = 0.61, p = 0.003. The mean T/QRS ratio of foetuses born with an umbilical artery pH of > 7.15 was 0.12 (range -0.05-0.32). There was no significant difference in mean T/QRS ratio between foetuses born with an umbilical artery pH < 7.16 (n = 10) and those born with a pH > 7.15. No trend in T/QRS ratio was found as labour progressed. There were only three cases of metabolic acidose (SBE = -10.3 to -10.6 mmol/l and pH = 7.09-7.14. In two of the cases the CTG was abnormal and in one case intermediate; mean T/QRS ratio was normal in all three cases with metabolic acidosis. Abnormal CTG was able to predict an umbilical artery pH < 7.15 with a sensitivity of 67% and a positive predictive value of 27%. T/QRS ratio (T/QRS = -0.05-0.25: "normal") was not able to predict a low pH. The chance of finding significant changes in T/QRS ratio was limited by the small number of foetuses with clinically significant acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Orthotopic liver transplantation with arterial re-anastomosis in the rat--a detailed description of technique and analysis of possible errors].

Liver transplantation (LTX) in the rat is a frequently used transplantation model. In the present study we give a detailed description of the suture technique for all anastomoses, except the bile duct, with arterialization of the transplanted liver over an aortoceliac segment to the recipient's aorta. Using this technique, we finally achieved survival rates of 80%. During the development stages, the main cause of death was an exceedingly long anhepatic time (> 20 min); later on, complications occurred only from insufficient anastomoses. The advantage of the suture technique over the cuff technique is that a more physiological anastomosis is obtained with less trauma to the recipient when using rearterialization. Despite the complicated suture technique, the anhepatic time can be well reduced to below 20 min.

Anastomosis, Surgical↗
PubMed1993

Coexistence of oxytocin and tyrosine hydroxylase in the rat hypothalamus, an immunocytochemical study.

Immunocytochemical double labelling was used to determine the structural relationship of oxytocin (OT) and tyrosine hydroxylase (TH) containing perikarya and processes in the rat hypothalamus. Extrahypothalamic TH fibers, as well as parvocellular TH neurons were found to form contacts with OT cells. A fraction of the OT neurons contained TH immunoreactivity. It is likely that in addition to the classical mesencephalic afferences also hypothalamic interneurons and magnocellular dopaminergic neurons control the hypothalamo neurohypophysial system.

Animals↗
PubMed1993

Cystic neuroblastoma in a newborn.

A neuroblastoma that presented as an adrenal cyst in a newborn infant is described. This is an extremely unusual presentation for neuroblastoma; it emphasizes the need for a high degree of suspicion when evaluating any abdominal mass in the newborn.

Adrenal Gland Diseases↗
PubMed1993

Fetal transcutaneous PCO2 measurements during labour.

The departments of Obstetrics and Gynaecology of the Universities of Bonn and Copenhagen and the Free University of Amsterdam cooperated in the European Community Concerted Action Project 'New methods for Perinatal Surveillance'. In 95 patients fetal transcutaneous PCO2 (tcPCO2) recording (measuring temperature 41 degrees C) during labour was evaluated regarding its clinical applicability. During the first stage of labour fetal tcPCO2 was rather stable at a level of 7.3 +/- 1.4 kPa. In the second stage there were marked differences between the three subpopulations. In the first stage of labour the correlation between tcPCO2 and PCO2 in fetal blood samples was 0.38 (P = 0.02) and in the second stage -0.20 (P = 0.36). The correlation of fetal tcPCO2 with umbilical artery PCO2 was 0.30 (P = 0.01) and with pH -0.30 (P = 0.01). Using a fetal tcPCO2 level of 8.0 kPa as a cut-off point to predict an umbilical artery pH less then 7.20, sensitivity was 88%, specificity 65%, positive predictive value 29% and negative predictive value 97%. The likelihood ratio of a positive test was 2.47 and of a negative test 0.13. It is concluded that fetal tcPCO2 possibly can be an additional tool to exclude fetal acidosis. In case of values above 8.0 kPa further evaluation of the fetal acid-base balance is indicated.

Blood Gas Monitoring, Transcutaneous↗
PubMed1993

Prediction of mode of delivery and 'DisFIL score' following induction of labor by local PGE2.

The objective of the study was to evaluate pre-induction risk factors for (i) assisted vaginal delivery (forceps or vacuum extraction), (ii) caesarean section, (iii) failed induction followed by caesarean section, and from these to evaluate a score of the 'Disadvantages Following Induction of Labour' (the DisFIL score). The study was a case-control study applied on a prospective cohort of 336 pregnant women induced by local PGE2. Assisted vaginal delivery was associated with primiparity (OR (odds ratio) = 10.7; CI, 3.6-32.0) and higher pelvic scores (Bishop score: OR = 1.9; CI, 1.4-2.6). Caesarean section was related to higher maternal age (P < 0.001) and lower pelvic scores (Bishop score: OR = 0.7; CI, 0.5-1.0, P < 0.05). When performed because of fetal distress, assisted vaginal delivery and caesarean section were both associated with lower fetal weights (P < 0.05). Failed induction followed by caesarean section was related to primiparity (P < 0.0001, Fisher's test) and lower pelvic scores (Bishop score: OR = 0.6; CI, 0.4-0.9). A higher 'DisFIL score' was associated with primiparity (OR = 4.7; CI, 2.8-8.0), higher maternal age (P < 0.01), lower pelvic scores (P < 0.01, chi 2 test) and PGE2 in intracervical gel rather than in vaginal pessaries (OR = 2.1; CI, 1.4-3.2). It is concluded that the major predictors of 'Disadvantages Following Induction of Labor' by local PGE2 are primiparity, high maternal age, low pelvic scores and the method of.

Adult↗
PubMed1993

Role of the regulatory gene pl in the photocontrol of maize anthocyanin pigmentation.

The pl gene encodes a regulatory protein that controls the transcription of a number of structural genes of the anthocyanin biosynthetic pathway in maize. pl alleles have been classified phenotypically into two categories: dominant (Pl) alleles lead to intense, light-independent pigmentation in vegetative and floral organs of the plant; recessive "sun-red" alleles (pl) lead to light-dependent red pigmentation in which only tissues exposed to light become pigmented. Based on these observations, two alternate pathways leading to anthocyanin synthesis in the plant have been proposed: one requiring light and the other bypassing the light requirement through the action of Pl. To evaluate this hypothesis, we have analyzed light-independent and light-dependent alleles of pl. Sequence analysis revealed that the two types of alleles have very distinct promoters but have the capacity to encode very similar proteins. The protein encoded by one recessive allele was shown to be functional in transient assays. Measurements of husk mRNA levels by quantitative polymerase chain reaction showed that sun-red pl alleles are expressed at much lower levels than a Pl allele, but their expression is increased approximately sixfold by exposure to light. These results lead to the conclusion that the sun-red pl alleles are not null; instead, they synthesize functional mRNA and protein. We propose that the light-dependent pigmentation observed in pl plants is the result of a threshold effect in which light exposure boosts pl mRNA expression past a crucial level necessary to generate sufficient PL protein molecules to activate transcription of the anthocyanin structural genes.

Alleles↗
PubMed1993

Hypothyroidism and anti-endothelial cell antibodies.

Because of our previous demonstration of anti-endothelial cell antibodies (AECA) in patients with insulin-dependent diabetes mellitus and their association, in this condition, with thyroid disease, we sought these antibodies in patients with suspected thyroid dysfunction using an enzyme immunoassay with human umbilical vein endothelial cells as the substrate. AECA were found in 5/120 (4.2%) patients with normal and 15/97 (15.4%) with abnormal thyroid function. The increased prevalence in the latter group was due to a highly significant association between the presence of AECA and raised levels of TSH. We conclude that a highly significant correlation exists between the levels of AECA and TSH, but not between those of AECA and fT4. Patients with hypothyroidism as defined by high levels of TSH have AECA significantly more often than patients with low or normal TSH (22.2% versus 2.8% and 5.8%).

Aged↗
PubMed1993

Colorimetric solid-phase minisequencing assay illustrated by detection of alpha 1-antitrypsin Z mutation.

In solid-phase minisequencing, a defined point mutation is detected in microtiter plate-immobilized DNA by a single nucleotide primer extension reaction. We have here developed the method into a colorimetric assay and applied it to the detection of the Z mutation of the alpha 1-antitrypsin gene. We used novel nucleoside triphosphates modified with dinitrophenyl (DNP) hapten, permitting detection by anti-DNP-alkaline phosphatase conjugate, with p-nitrophenyl phosphate as substrate. The Z mutation is detected in two reactions: DNP-labeled dCTP is incorporated when the template is normal, DNP-dUTP when the Z mutation is present. Both modified nucleotides were incorporated with high specificity and with an efficiency similar to that of unmodified nucleotides. The test results are measured by spectrophotometry, yielding quantitative absorbance values. Calculation of the ratio of C to U signal permitted unambiguous distinction of normal homozygous, ZZ homozygous, and ZM heterozygous genotypes. The colorimetric minisequencing assay is rapid, standardized, and automatable, and thus provides an accurate and simple alternative for the analysis of known point mutations.

Base Sequence↗