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Biomedical subjects

J Partanen

Publications and source records attributed to J Partanen.

At least 19 recordsLinked to original sources
PubMed1992

Enhanced expression of the tie receptor tyrosine kinase in endothelial cells during neovascularization.

We have recently cloned a novel human receptor tyrosine kinase, tie, from human leukemia cells showing megakaryoblastoid differentiation. We report here that the 4.4-kb tie messenger RNA (mRNA) is present in all human fetal and mouse embryonic tissues. By in situ hybridization, the tie mRNA was localized to the endothelia of blood vessels and endocardium of 9.5- to 18.5-day mouse embryos. However, tie was not expressed by endothelial cells of developing hepatic sinusoids. Increased tie mRNA signal was seen in proliferating ovarial capillaries during hormone-induced superovulation. Only a weak tie signal was obtained from adult skin, except during wound healing, when the proliferating capillaries in the granulation tissue contained abundant tie RNA. These results suggest that tie may have a role in neovascularization.

Amino Acid Sequence↗
PubMed1992

Plasmid pLTRpoly: a versatile high-efficiency mammalian expression vector.

Plasmid pLTRpoly is an expression vector enabling high-level expression of introduced genes in a variety of cell types. A large multiple cloning site (MCS) and the availability of the full-length nucleotide sequence facilitate the generation of constructs using this vector. Here, constructs made with pLTRpoly have been tested in NIH3T3 mouse fibroblasts.

3T3 Cells↗
PubMed1992

Expression of fibroblast growth factor receptors in human leukemia cells.

We have previously cloned from K562 leukemia cells two novel fibroblast growth factor receptors (FGFR-3 and FGFR-4; J. Partanen et al., EMBO J., 10: 1347-1354, 1991). Here we have analyzed the mRNA expression of four different FGFRs, including the two novel genes in human leukemia cell lines. We show FGFR-1, FGFR-3, and FGFR-4 mRNAs in several leukemia cell lines at levels similar to those in solid tumor cell lines. Ligand cross-linking experiments indicate that K562 cells have receptors binding acidic FGF but not basic FGF. Expression of FGFRs in leukemia cells may reflect their presence on normal hematopoietic precursor cells or induction during leukemogenesis or cell culture.

Blotting, Northern↗
PubMed1992

Slowing of the dominant occipital rhythm in electroencephalogram is associated with low concentration of noradrenaline in the thalamus in patients with Alzheimer's disease.

The thalamus is involved in the regulation of the neocortical rhythmicity reflected in EEG as the alpha rhythm. Recent evidence suggests that the thalamus is affected in Alzheimer's disease (AD). We studied the relationship between the dominant occipital rhythm of the lifetime EEG and the choline acetyltransferase activity (ChAT) and monoamine concentrations in the postmortem thalamus of 20 histologically verified AD patients. The AD patients were divided into 3 groups (5-6 Hz, 7 Hz and 8-9 Hz) according to the frequency of the dominant occipital rhythm (FOC). Noradrenaline (NA) concentrations were significantly lower for the 5-6 Hz and 7 Hz subgroups as compared to the 8-9 Hz subgroup. The NA content of the thalamus correlated significantly with the FOC (r = 0.46, P = 0.04). The ChAT activity or concentrations of dopamine or serotonin did not correlate with the FOC or differ across the AD subgroups. The results suggests that the noradrenergic deficit of the thalamus may contribute to slowing of the dominant occipital rhythm in AD.

Aged↗
PubMed1992

Analysis of tyrosine kinase mRNAs including four FGF receptor mRNAs expressed in MCF-7 breast-cancer cells.

The MCF-7 cell line is a hormone-responsive human breast-cancer cell line, which has been extensively used in studies of estrogen regulation of cell growth. These studies have indicated that the growth stimulation of the MCF-7 cells by estrogens may be effected by an autocrine mechanism involving several growth factors, such as EGF, TGF alpha and IGF-I and their receptors. We have amplified and cloned tyrosine-kinase-related sequences from the MCF-7 cell mRNA using the polymerase chain reaction and characterized the partial cDNAs obtained by nucleic acid sequencing. Nine tyrosine kinase cDNAs and one serine/threonine kinase cDNA were identified among the amplified sequences. Four different tyrosine kinase genes encoding receptors for fibroblast growth factors (FGFs) were found to be expressed by the MCF-7 cells. In addition, differences were observed in the expression of these members of FGF receptor family in different breast-cancer cells. A putative tyrosine-kinase receptor and a novel serine/threonine kinase were preferentially expressed in estrogen-responsive tumor cell lines. However, no estrogen-dependent regulation of any of the novel tyrosine-kinase receptor mRNAs was found in any of the cell lines including the MCF-7 or ZR-75-I cells, where the expression of the neu proto-oncogene mRNA was decreased during estrogen treatment. The expression of several FGF receptors by breast-cancer cells suggests that FGFs may be involved in their growth regulation and tumorigenesis.

Amino Acid Sequence↗
PubMed1992

FLT4, a novel class III receptor tyrosine kinase in chromosome 5q33-qter.

The receptors for at least two hematopoietic growth factors, namely the stem cell factor and colony-stimulating factor 1, belong to class III receptor tyrosine kinases. Here we describe cloning of a partial complementary DNA for FLT4, an additional member of this gene family from human leukemia cells. The FLT4 tyrosine kinase domain is 79% homologous with the previously cloned FLT1 (M. Shibuya et al., Oncogene, 5: 519-524, 1990) tyrosine kinase and maps to the chromosomal region 5q33-qter. We have found FLT4 expression in human placenta, lung, heart, and kidney, whereas the pancreas and brain appeared to contain very little if any FLT4 RNA. The results suggest that FLT4 functions in multiple adult tissues.

Adult↗
PubMed1992

Magnetoencephalographic localization of epileptic cortex--impact on surgical treatment.

A 24-channel, planar, superconducting quantum interference device gradiometer, sampling a fourth of the head surface over brain tissue, was used to determine the site of an epileptic focus in a 36-year-old woman with intractable complex partial epilepsy. The other presurgical findings appeared divergent: a large arachnoid cyst over the right parietal convexity, dissimilar interictal electroencephalographic patterns, and several neuropsychological dysfunctions. The equivalent current sources of magnetoencephalographic spikes were in the right posterior temporal region of the cortex, 4 cm apart from the cyst. Surgical exploration of the area pinpointed by magnetoencephalography revealed a pachygyric patch of cortex displaying focal discharges on the electrocorticogram. After resection, a dramatic reduction of seizures occurred. The good agreement between electrocorticography and magnetoencephalography warrants future investigation of multichannel magnetoencephalography as a potential alternative to invasive presurgical recordings.

Adult↗
PubMed1992

Localization of the fibroblast growth factor receptor-4 gene to chromosome region 5q33-qter.

Our polymerase chain reaction cloning of novel tyrosine kinases expressed in the K562 chronic myeloid leukemia cells has revealed a novel fibroblast growth factor receptor, FGFR4. We have here mapped the FGFR4 gene by analysis of somatic cell hybrids and in situ hybridization to the 5q33-qter chromosomal region. This finding is of interest in that the FGFR4 gene is expressed in several leukemia cell lines and the 5q33-qter region is involved in nonrandom chromosomal translocations in acute myelogenous leukemias and Ki-I lymphomas.

Chromosome Mapping↗
PubMed1992

The human p50csk tyrosine kinase phosphorylates p56lck at Tyr-505 and down regulates its catalytic activity.

Protein tyrosine kinases participate in the transduction and modulation of signals that regulate proliferation and differentiation of cells. Excessive or deregulated protein tyrosine kinase activity can cause malignant transformation. The catalytic activity of the T cell protein tyrosine kinase p56lck is normally suppressed by phosphorylation of a carboxyl-terminal tyrosine, Tyr-505, by another cellular protein tyrosine kinase. Here we characterize a human cytosolic 50 kDa protein tyrosine kinase, p50csk, which specifically phosphorylates Tyr-505 of p56lck and a synthetic peptide containing this site. Phosphorylation of Tyr-505 suppressed the catalytic activity of p56lck. We suggest that p50csk negatively regulates p56lck, and perhaps other cellular src family kinases.

Amino Acid Sequence↗
PubMed1992

Fibroblast growth factor receptor-4 shows novel features in genomic structure, ligand binding and signal transduction.

Fibroblast growth factor (FGF) receptor (FGFR) gene family consists of at least four receptor tyrosine kinases that transduce signals important in a variety of developmental and physiological processes related to cell growth and differentiation. Here we have characterized the binding of different FGFs to FGFR-4. Our results establish an FGF binding profile for FGFR-4 with aFGF having the highest affinity, followed by K-FGF/hst-1 and bFGF. In addition, FGF-6 was found to bind to FGFR-4 in ligand competition experiments. Interestingly, the FGFR-4 gene was found to encode only the prototype receptor in a region where both FGFR-1 and FGFR-2 show alternative splicing leading to differences in their ligand binding specificities and to secreted forms of these receptors. Ligands binding to FGFR-4 induced receptor autophosphorylation and phosphorylation of a set of cellular polypeptides, which differed from those phosphorylated in FGFR-1-expressing cells. Specifically, the FGFR-1-expressing cells showed a considerably more extensive tyrosine phosphorylation of PLC-gamma than the FGFR-4-expressing cells. Structural and functional specificity within the FGFR family exemplified by FGFR-4 may help to explain how FGFs perform their diverse functions.

Alternative Splicing↗
PubMed1992

Slowing of electroencephalogram and choline acetyltransferase activity in post mortem frontal cortex in definite Alzheimer's disease.

Twenty-five (96%) of 26 patients with histologically verified moderate to severe Alzheimer's disease had abnormal electroencephalograms. The patients with the slowest (5-6 Hz) dominant occipital rhythms had significantly lower choline acetyltransferase activity in the post mortem frontal cortex than the patients with highest rhythm (8-9 Hz) (analysis of covariance adjusted for the neuropsychological test score). Concentrations of dopamine, noradrenaline or serotonin in the frontal cortex did not differ in the patient groups with the slowest and highest rhythms. Neither did scores of senile plaques or neurofibrillary tangles differ between these groups. In Alzheimer patients, the frequency of the dominant occipital rhythm correlated with the total score of the neuropsychological test (r = 0.58, P less than 0.01) and with the subscales of praxic functions and expressive speech, memory and general reasoning. The results suggest that the cholinergic deficit may contribute to the slowing of the electroencephalogram found in patients with Alzheimer's disease.

Aged↗
PubMed1992

Amino acid levels in cerebrospinal fluid of rats after administration of pentylenetetrazol.

1. We studied the effect of pentylenetetrazol (PTZ)-induced myoclonic jerks and generalized clonic-tonic convulsions (GC) on the levels of neurotransmitter amino acids in the cisternal CSF of rats. 2. The levels of aspartate, glutamate, glycine, and taurine were elevated in the CSF during myoclonic jerks and more distinctly immediately after GC. 3. During the recovery period of postictal depression seen in EEG (5 min after GC), the CSF levels of transmitter amino acids were lower than in the control group. 4. PTZ-induced irritative activity in the EEG disappeared in 24 hr but the levels of amino acids remained abnormal. 5. Amino acid changes in the CSF following PTZ-induced convulsions might indicate that the release of amino acids into the extracellular space is increased before and during the propagation of PTZ-induced seizure and decreased during postictal depression.

Amino Acids↗
PubMed1992

Diverse receptors for fibroblast growth factors.

The development and maintenance of multicellular organisms requires a complex interplay between cells in different tissues. Many of the factors mediating cell-cell communication are polypeptides, which were originally identified because of their ability to stimulate cell growth. In addition to growth signalling several of these factors have been observed to modulate cell survival, chemotaxis and differentiation both in vitro and in vivo. Fibroblast growth factors are a good example of polypeptide mitogens eliciting a wide variety of responses depending on the target cell type. Our knowledge of the cell surface receptors mediating the effects of FGFs has recently expanded remarkably. Perhaps not surprisingly, the complexity of the FGF family and FGF induced responses is reflected as diversity and redundancy of the FGF receptors.

Amino Acid Sequence↗
PubMed1992

Aging and spectral analysis of EEG in normal subjects: a link to memory and CSF AChE.

We studied the effect of aging on EEG spectra recorded from T5-O1 (T6-O2) derivation. The aging series composed of 52 normal individuals aged 20 to 91 years. Seventy-nine per cent of visual and 81% of quantitative EEGs were considered normal. The absolute amplitude of delta and theta bands and absolute power of delta band were lower for the oldest group (aged 60 and over) than for the youngest group (aged 20-39 years). Age was inversely related to the amount of delta and theta indicating that the amount of slow activity in quantitative EEG does not increase with age in the context of good health status. Women had more beta activity compared with men. In addition, the amount of beta and alpha bands showed tendency for a reduction with age. Fifteen subjects aged 50 years or older participated in a 2-year follow-up including EEG and neuropsychological evaluation. Seven of them deteriorated in learning ability and showed increase in delta activity. In the oldest age group, delta amplitude was positively correlated with intrusion errors in the list learning test and inversely related to acetylcholinesterase activity of the CSF. Thus, a link between the cholinergic system, EEG slowing and memory problems in old age is suggested.

Acetylcholinesterase↗
PubMed1992

Major histocompatibility complex located complement C4 and steroid 21-hydroxylase gene rearrangements in couples with recurrent spontaneous abortions.

Major Histocompatibility Complex (MHC) class III located complement C4 and steroid 21-hydroxylase (21OH) genes, which form various deletion and duplication units, were studied by TaqI Restriction Fragment Length Polymorphism (RFLP) in 58 Finnish couples who suffered recurrent spontaneous abortions (RSA). The gene rearrangements found in the RSA couples did not differ from those in the controls.

Abortion, Habitual↗