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Biomedical subjects

K Lindner

Publications and source records attributed to K Lindner.

At least 19 recordsLinked to original sources
PubMed2005

[Management of coagulation after multiple trauma].

Hemorrhage after traumatic injury results in coagulopathy which only worsens the situation. This coagulopathy is caused by depletion and dilution of clotting factors and platelets, increased fibrinolytic activity, hypothermia, metabolic changes and anemia. The effect of synthetic colloids used for compensating the blood loss, further aggravates the situation through their specific action on the hemostatic system. Bedside coagulation monitoring permits relevant impairment of the coagulation system to be detected very early and the efficacy of the hemostatic therapy to be controlled directly. Administration of fresh frozen plasma (FFP), platelet concentrates and antifibrinolytic agents is essential for restoring the impaired coagulation system in trauma patients. Clotting factor concentrates should be administered if coagulopathy is based on diagnosed depletion of clotting factors, if FFP is not available and if transfusion of FFP is insufficient to treat the coagulopathy. Recombined FVIIa is frequently employed during severe bleeding which could not be treated by conventional methods but the results of on-going clinical trials are not yet available.

Anticoagulants↗
PubMed2004

Removal of persistent polar pollutants through improved treatment of wastewater effluents (P-THREE).

The EU-project P-THREE started with the establishment of analytical methods for persistent polar pollutants (P3) and quality assurance, followed by screening of P3 in influents and effluents of known wastewater (WW) treatment plants (TP), receiving waters and tap water produced thereof in several European countries. A final selection of analytes for further studies has been performed. Model MBR reactors have been constructed and an optimisation on synthetic wastewater spiked with P3 (linear alkylbenzene sulfonates (LAS), naphthalene sulfonates) has been performed. An initial dynamic modelling of treatment processes has also started. Advanced oxidation process (AOP) treatment has been done in groundwater with isoproturon and nonylphenol ethoxylates (NPEO). The analysis of individual P3 and potential degradation products was also performed. An integrated systeme analysis of the WW treatment processes has also been initiated.

Alkanesulfonic Acids↗
PubMed2002

Congenital malformations in 4224 children conceived after IVF.

BACKGROUND: The percentage of children born after IVF will continue to increase due to demographic changes such as increasing maternal age and new developments in assisted reproduction techniques. IVF conceptions may carry an increased risk of congenital malformations. METHODS: We compared overall and specific congenital malformation rates calculated for IVF children (n = 4224) and naturally conceived children (n = 314 605), using records from the same Dutch national database for the years 1995 and 1996 and controlling for confounding maternal factors. RESULTS: The overall crude odds ratio (OR) for the risk of any malformation for IVF children compared with naturally conceived children was 1.20 [95% confidence interval (CI): 1.01-1.43]. After correction for differences in maternal age, parity and ethnicity between the IVF and control population the OR was 1.03 (95% CI: 0.86-1.23). The crude OR for IVF children appeared higher for the cardiovascular organ system and for several specific minor congenital malformations. However, these could be chance findings due to comparison of many malformation categories or may result from remaining differences in ascertaining malformations between IVF and naturally conceived children. CONCLUSIONS: The small increase in overall congenital malformations observed in the IVF children appears to be attributable to differences in maternal characteristics and not to any aspect of the IVF procedure.

Adult↗
PubMed2000

Chromatin binding of the fission yeast replication factor mcm4 occurs during anaphase and requires ORC and cdc18.

We describe an in situ technique for studying the chromatin binding of proteins in the fission yeast Schizosaccharomyces pombe. After tagging the protein of interest with green fluorescent protein (GFP), chromatin-associated protein is detected by GFP fluorescence following cell permeabilization and washing with a non-ionic detergent. Cell morphology and nuclear structure are preserved in this procedure, allowing structures such as the mitotic spindle to be detected by indirect immunofluorescence. Cell cycle changes in the chromatin association of proteins can therefore be determined from individual cells in asynchronous cultures. We have applied this method to the DNA replication factor mcm4/cdc21, and find that chromatin association occurs during anaphase B, significantly earlier than is the case in budding yeast. Binding of mcm4 to chromatin requires orc1 and cdc18 (homologous to Cdc6 in budding yeast). Release of mcm4 from chromatin occurs during S phase and requires DNA replication. Upon overexpressing cdc18, we show that mcm4 is required for re-replication of the genome in the absence of mitosis and is associated with chromatin in cells undergoing re-replication.

Anaphase↗
PubMed1999

Analysis of mice carrying targeted mutations of the glucocorticoid receptor gene argues against an essential role of glucocorticoid signalling for generating adrenal chromaffin cells.

Molecular mechanisms underlying the generation of distinct cell phenotypes is a key issue in developmental biology. A major paradigm of determination of neural cell fate concerns the development of sympathetic neurones and neuroendocrine chromaffin cells from a common sympathoadrenal (SA) progenitor cell. Two decades of in vitro experiments have suggested an essential role of glucocorticoid receptor (GR)-mediated signalling in generating chromaffin cells. Targeted mutation of the GR should consequently abolish chromaffin cells. The present analysis of mice lacking GR gene product demonstrates that animals have normal numbers of adrenal chromaffin cells. Moreover, there are no differences in terms of apoptosis and proliferation or in expression of several markers (e.g. GAP43, acetylcholinesterase, adhesion molecule L1) of chromaffin cells in GR-deficient and wild-type mice. However, GR mutant mice lack the adrenaline-synthesizing enzyme PNMT and secretogranin II. Chromaffin cells of GR-deficient mice exhibit the typical ultrastructural features of this cell phenotype, including the large chromaffin granules that distinguish them from sympathetic neurones. Peripherin, an intermediate filament of sympathetic neurones, is undetectable in chromaffin cells of GR mutants. Finally, when stimulated with nerve growth factor in vitro, identical proportions of chromaffin cells from GR-deficient and wild-type mice extend neuritic processes. We conclude that important phenotypic features of chromaffin cells that distinguish them from sympathetic neurones develop normally in the absence of GR-mediated signalling. Most importantly, chromaffin cells in GR-deficient mice do not convert to a neuronal phenotype. These data strongly suggest that the dogma of an essential role of glucocorticoid signalling for the development of chromaffin cells must be abandoned.

Adrenal Glands↗
PubMed1998

Epitope mapping of antibodies recognising the N-terminal domain of simian virus large tumour antigen.

The large tumour antigen (TAg) of simian virus 40 is the main regulatory protein in viral replication. We have investigated possible functional roles for the N-terminal domain of TAg while defining the epitopes of antibodies binding within that region. The epitopes recognised by eight monoclonal anti-TAg antibodies were identified using synthetic peptides in an enzyme-linked immunosorbent assay. For antibodies PAb 223, 281, 211, 219 and 224, epitopes varied in length between ten and fifteen amino acids. Two antibodies, PAb 210 and PAb 419, could not be mapped any further using this technique. Antibody PAb 416 recognised a pentapeptide WEQWW that could be involved in topoisomerase I binding and possibly in the interaction between topoisomerase I and simian virus reverse transcriptase.

Amino Acid Sequence↗
PubMed1997

Increased duration and altered topography of EEG microstates during cognitive tasks in chronic schizophrenia.

The surface EEGs of 32 medicated chronic schizophrenic patients, 12 unmedicated chronic schizophrenics and 35 matched healthy controls were analyzed by adaptive segmentation of continuous EEG during a rest condition, a mental arithmetic task, and a CNV paradigm. Results indicate increased duration of brain microstates in both unmedicated and medicated schizophrenics as well as reduced topographic variability. These findings did not vary across the different tasks. Comparing different cognitive tasks, schizophrenics and controls alike showed task-related changes of electric field topography, of EEG microstate duration and of the number of very short microstates (single-peak segments). However, the topography of the microstates during the tasks differed significantly in both medicated and unmedicated schizophenics from that of controls. Age, sex and educational levels did not influence these findings. Neuroleptic medication correlated negatively with microstate duration in a dose-dependent way. There was an inverse relationship between topographic variability and negative symptoms as well as BPRS scores. It is concluded that the temporo-spatial characteristics of brain electric activity indicate an impoverished array of functional modes and enhanced stability of brain electrical microstates in schizophrenia.

Adult↗
PubMed1997

Percentage of hypochromic red blood cells as predictor of erythropoietic and iron response after i.v. iron supplementation in maintenance haemodialysis patients.

BACKGROUND: The percentage of hypochromic red blood cells (RBC), defined as those with a cellular haemoglobin < 28 g/dl has been suggested to be a sensitive marker of functional iron deficiency in maintenance haemodialysis (HD) patients. Thus, during rHuEpo therapy an increase in hypochromic RBC to > 10% would indicate that more intensive iron supplementation may be required. METHODS: We investigated 70 HD patients 57.1 +/- 15.3 years old and on maintenance HD for 66.3 +/- 47.9 months without blood loss from gastrointestinal bleeding or from the vascular access, without surgery and without infectious disease or malignancy. During the study period of 12 weeks, each patient received in i.v. dose of 800 mg ferrogluconate. Haemoglobin, haematocrit, and the percentage of hypochromic RBC were measured before and every 4 weeks after the start of the study; serum ferritin, zinc protoporphyrin (ZPP) and C-reactive protein (CRP) were measured at the beginning (baseline) and end of the study. RESULTS: At baseline the percentage of hypochromic RBC was < or = 5.0% in 28 patients, > 5.0 and < or = 10.0% in 25 patients and > 10.0% in 17 patients, suggesting functional iron deficiency in at least 42 patients. Nine patients had serum ferritin values < 100 micrograms/1; nonetheless in these patients the median percentage of hypochromic RBC was 5.9% (range 0.9-14.3%), indicating that an absolute iron deficiency can occur in the presence of normal amounts of hypochromic RBC. There was a significant correlation between serum ferritin levels and hypochromic RBC at the end, but not at the beginning, of the study. However, there was no correlation between ZPP and hypochromic RBC at any time during the study. During i.v. iron supplementation the rHuEpo dose could be reduced by 8.5% in patients with hypochromic RBC < or = 5.0%, by 11.3% in patients with hypochromic RBC > 5.0 and < or = 10.0% and by 23.4% in patients with hypochromic RBC > 10.0%, demonstrating the benefit of i.v. iron in patients with functional iron deficiency. In HD patients in whom serum ferritin levels remained below 290 micrograms/l until the end of the study, a significant reduction of the rHuEpo dosage could be obtained during i.v. iron therapy. This was not the case in patients with serum ferritin > 290 micrograms/l after iron supplementation. We found that the percentage of hypochromic RBC is the most sensitive parameter for predicting hyporesponsiveness in CRP-positive patients. HD patients with hypochromic RBC > 6% and low to moderate increases in serum ferritin levels after i.v. iron supplementation significantly benefit from i.v. iron therapy compared to HD patients with hypochromic RBC < 6%. CONCLUSIONS: Two different aspects should be taken into consideration in HD patients treated with rHuEpo and concomitant i.v. iron therapy: (1) response of the erythropoietic system to rHuEpo, and (2) adequate delivery of the supplemented iron to the erythropoietic system. The patient's percentage of hypochromic RBC and increase in serum ferritin after i.v. iron supplementation should be used to decide whether or not i.v. iron should be given and to monitor this type of therapy in HD patients.

Anemia, Hypochromic↗
PubMed1996

MRI in patients with general paresis.

Few cases of MRI in neurosyphilis have been reported. We examined the value of MRI in patients with general paresis; MRI was performed on four HIV-negative patients with parenchymatous neurosyphilis. It demonstrated frontal and temporal atrophy, subcortical gliosis and, in one patient, increased ferritin in the basal ganglia. The progression of the lesions on MRI correlated well with the neuropsychiatric disturbances. The MRI findings correlated with the well-known neuropathological findings. This combination of pathological findings in neurosyphilis has not been described before and we suggest that MRI is of prognostic value in patients with general paresis.

Adult↗
PubMed1994

Jarisch-Herxheimer reaction in a patient with neurosyphilis.

A 40 year old man presented with progressive personality changes in the previous six months. Specific serological tests for syphilis in blood and CSF were highly positive and CSF sedimentation showed signs of an inflammatory process. Ten hours after the start of penicillin treatment a severe symptomatic Jarisch-Herxheimer reaction with alteration of level of consciousness, pupillary changes, and focal neurological signs developed. Jarisch-Herxheimer reaction may occur in various settings, particularly in the treatment of syphilis. Investigation of CSF before the treatment may predict a potential risk. Corticosteroid treatment has been suggested for prevention.

Adult↗
PubMed1992

Thinking with images or thinking with language: a pilot EEG probability mapping study.

This pilot EEG mapping study was designed to explore thinking processes using complex mental imagery and thought processes. EEG was recorded with 19 electrodes (10/20 system against averaged ear lobe signals) while volunteers (n = 42) performed two separate tasks: visualization of an abstract concept and interpretation of a painting. Average spectral parameters such as amplitude, local and interhemispheric coherences were computed for five frequency bands (theta, alpha, beta 1, 2 and 3). Results indicate that the frontal regions are strongly involved during these tasks as evidenced by coherence changes. Changes are also present in temporal, parietal and occipital regions and are discussed in relation to information processing with the frontal regions considering the different cognitive functions required by the tasks.

Adolescent↗
PubMed1992

Dissociated unilateral convergence paralysis in a patient with thalamotectal haemorrhage.

A 47 year old male was admitted in a comatose state. CT scan showed a haemorrhage in the right pulvinar thalamus descending into the right part of the lamina quadrigemina. He presented with anisocoria, prompt bilateral pupillary light reaction, and unilateral convergence paralysis contralateral to the lesion in combination with upward gaze palsy. During an observation period of two months, the convergence reaction returned to normal. MRI showed a lacunar lesion ventral to superior right colliculus. Angiography revealed an arteriovenous malformation (right posterior cerebral artery--sinus rectus) as the possible cause of the haemorrhage.

Cerebral Hemorrhage↗