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H Persson

Publications and source records attributed to H Persson.

At least 91 records · Page 5Linked to original sources
PubMed1994

p75LNGFR regulates Trk signal transduction and NGF-induced neuronal differentiation in MAH cells.

We have examined NGF-induced signal transduction events and neuronal differentiation in MAH cells, a neuronal progenitor cell line, in which the expression of the two NGF receptors, p140trk (Trk) and p75LNGFR (p75), has been independently manipulated. Coexpression of a large molar excess of p75 substantially enhances the NGF-induced tyrosine autophosphorylation of Trk, compared with cells expressing Trk alone. MAH cells expressing both Trk and p75 stop dividing and acquire a mature neuronal morphology more rapidly and with greater efficiency than MAH cells expressing Trk alone. These biochemical and biological influences of p75 are not observed using a mutant form of NGF that binds Trk but not p75. These data provide evidence that p75 can modulate signal transduction through Trk in a neuronal progenitor cell context and that such modulation has functional consequences for the neuronal differentiation pathway induced by NGF.

Animals↗
PubMed1994

HLA-A incompatibility associated with enhanced long-term renal graft survival in HLA-B, DR mismatched transplants.

The effect of HLA-A matching on long-term cadaver kidney graft survival was analysed, on average, 6 years after transplantation in a total of 1085 cyclosporine (CyA)-treated patients. A beneficial effect of HLA-A mismatching on graft survival was found by univariate and multivariate analyses (P < 0.05). Enhanced graft survival was associated with HLA-A mismatching in transplants mismatched for HLA-B,DR (P = 0.03), but not in HLA-B,DR compatible transplants. High 6 year graft survival rates, 78% and 66%, were found in transplants mismatched for two or one HLA-A antigens, respectively, among patients without any acute rejection episode. This was significantly higher than the survival rate of 55% found in HLA-A compatible transplants (P = 0.001). In patients who had suffered from acute rejection episodes, a prolonged graft survival was also associated with HLA-A mismatching in HLA-B,DR mismatched transplants (P = 0.04). The beneficial effect on graft survival of HLA-A mismatching was most pronounced in patients treated with high/medium dose CyA and prednisolone (P = 0.004 overall and P = 0.0007 for HLA-B,DR mismatched transplants). In conclusion, HLA-A mismatching was associated with enhanced long-term renal graft survival in CyA-treated recipients of HLA-B,DR mismatched transplants. In clinical situations, the present results might, if confirmed, contribute to the prolongation of long-term graft survival. The results might indicate the existence of tolerance promoting allogeneic markers within the HLA-A class I region.

Diabetes Mellitus↗
PubMed1994

Antivenom treatment in Vipera berus envenoming--report of 30 cases.

OBJECTIVES: To assess efficacy and safety of two equine F(ab')2 antivenoms currently used to treat envenoming by European vipers. DESIGN: Retrospective case review study. SETTING: Case records collected by the Swedish Poison Information Centre concerning patients treated in Swedish hospitals for bites by the common European adder, Vipera berus. SUBJECTS: Patients presenting with V. berus envenoming treated with antivenom (n = 30) and two groups of patients not given antivenom (n = 16 and n = 38). MAIN OUTCOME MEASURES: Clinical course and time in hospital were retrospectively studied and compared in patients treated or not treated with antivenom. RESULTS: There was a significantly lower incidence of extensive oedema (23 vs. 88%) and anaemia (10 vs. 50%) in the antivenom-treated group, and the hospital stay was shorter (median: 3 vs. 6 days). Antivenom treatment also resulted in prompt clinical improvement in the acute phase. Adverse effects consisting of urticaria and serum sickness occurred in 10% of the patients given antivenom. CONCLUSIONS: Antivenom treatment was associated with a reduced morbidity in severe V. berus envenoming. However, the occurrence of allergic side-effects is not negligible with this type of antivenom.

Adolescent↗
PubMed1994

Trk mRNA and low affinity nerve growth factor receptor mRNA expression and triploid DNA content in favorable neuroblastoma tumors.

Nerve growth factor (NGF) is suggested to play a role in spontaneous differentiation or regression of neuroblastoma. Expression of mRNAs for trk protooncogene and NGF low affinity receptor gene (LNGFR) were analyzed in 45 neuroblastomas with Northern Blot. Trk and LNGFR expression correlated with young age, localized tumors or IV-S disease, absence of N-myc amplification, triploid DNA content, spontaneous tumor regression and favorable prognosis. Regardless of other factors, trk and LNGFR mRNAs distinguished three prognostic subsets: one favorable (trk+, LNGFR+, n = 19, 100% survival probability), one intermediate (trk+, LNGFR-, n = 11, 62%) and one poor (trk-, n = 15, 0%). An algorithm based on the combined analysis of trk and LNGFR mRNAs and DNA ploidy divided the material in two groups with 96 and 0% survival probability respectively (p < 0.001), and predicted outcome accurately in 43 of 45 children. It is hypothesized that loss of functional NGF-receptors constitutes an early critical step in the evolution of unfavorable neuroblastomas prone to progression in spite of current therapy.

DNA, Neoplasm↗
PubMed1994

Expression of nerve growth factor receptor mRNAs and clinical response to retinoic acid in neuroblastoma.

Four children with advanced or relapsed neuroblastoma were treated with oral 13-cis-retinoic acid 0.75 mg/kg/day. Clinical response to retinoic acid was noted only in the two children with tumors coexpressing trk protooncogene mRNA, encoding an essential part of the nerve growth factor (NGF) high affinity receptor, and low affinity NGF receptor gene (LNGFR) mRNA. Clinical stage or age, plasma neuropeptide Y, tumor DNA ploidy and N-myc amplification did not as accurately predict response to retinoic acid as NGF receptor mRNAs. In vitro data have shown that retinoic acid up regulates LNGFR expression and NGF sensitivity via interaction with specific regulatory elements in the LNGFR gene promoter. We hypothesize that part of the therapeutic effect of retinoic acid in neuroblastoma in vivo may be exerted via increased NGF receptor expression and NGF sensitivity. Analysis of trk and LNGFR mRNA may be useful to predict clinical response to retinoic acid in these children.

Administration, Oral↗
PubMed1994

Expression of mRNAs encoding ARPP-16/19, ARPP-21, and DARPP-32 in human brain tissue.

In this study we have isolated and sequenced human cDNAs for the phosphoproteins DARPP-32, ARPP-21, and ARPP-16/19, and have compared these sequences to previously characterized bovine and rat cDNAs. In situ hybridization and Northern blot analysis with the human cDNA probes were used to study the expression of mRNAs encoding ARPP-16/19, ARPP-21, and DARPP-32 in human postmortem brain tissue. In situ hybridization was performed using horizontal whole hemisphere sections. Five representative levels of the brain ranging from 71 mm to 104 mm ventral to vertex were examined. All three probes showed distinct hybridization patterns in the caudate nucleus, putamen, nucleus accumbens, and the amygdaloid complex. For ARPP-16/19 mRNA, a hybridization signal comparable to the signal in caudate nucleus, putamen, and nucleus accumbens was also detected in the neocortex. ARPP-21 and DARPP-32 mRNA, on the other hand, were present in lower levels in neocortical regions. DARPP-32 mRNA was abundant in the cerebellar cortex at the level of the Purkinje cell layer. High levels of ARPP-16/19 and ARPP-21 mRNA were also found in the cerebellar cortex, where they were confined to deeper layers. The present result demonstrate that mRNAs for the three phosphoproteins are expressed in overlapping, but also distinct, areas of the human brain that in many cases coincide with previously described distribution of the dopamine D1 receptor.

Aged↗
PubMed1993

Differential usage of multiple brain-derived neurotrophic factor promoters in the rat brain following neuronal activation.

The rat brain-derived neurotropic factor (BDNF) gene consists of four 5' exons linked to separate promoters and one 3' exon encoding the prepro-BDNF protein. To gain insights into the regulation of BDNF mRNA expression, probes specific for the different 5' exons were used to study the expression of BDNF mRNA in the brain. Following a systemic injection of the glutamate analog kainic acid, exon I, II, and III mRNAs increased transiently in hippocampus and cerebral cortex. A modest increase was seen for exon IV, where a new transcription initiation site was induced by this treatment. Pretreatments with the N-methyl-D-aspartate (NMDA) receptor antagonist MK801 or the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist 2,3-dihydroxy-6-nitrosulfanoylbenzo(f)quinoxaline revealed two region-specific patterns of glutamate receptor-mediated regulation. The first pattern found in neocortex, piriform cortex, and amygdala involves regulation of BDNF exon I, II, and III mRNAs through NMDA and AMPA/kainate receptors. The second pattern found in the hippocampus involves regulation of BDNF exon I, II, and III mRNAs by high-affinity kainate or metabotropic receptors. Treatment with the gamma-aminobutyric acid subtype A (GABAA) receptor antagonist bicuculline increased exon I and III mRNAs in the denate gyrus, and the muscarinic receptor agonist pilocarpine increased exon I mRNA mainly in the neocortex. These data show that the four BDNF promoters allow multiple points of BDNF mRNA regulation and suggest that the activation of different subtypes of glutamate receptors differentially regulates the expression of BDNF exon-specific mRNAs in the brain.

Animals↗
PubMed1993

Coexpression of neurotrophins and their receptors in neurons of the central nervous system.

Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are neuronal survival molecules which utilize the Trk family of tyrosine kinase receptors. Using double-label in situ hybridization, we demonstrate that mRNAs for BDNF and its high-affinity receptor TrkB are coexpressed in hippocampal and cortical neurons. Also, a large number of neurons in these areas coexpress NGF and BDNF mRNAs. Epileptic seizures lead to increased levels of both BDNF/TrkB and NGF/BDNF mRNAs in double-labeled cells. Our results show that individual neurons of the central nervous system can coexpress neurotrophins and their receptors and produce two neurotrophic factors. These factors could support neuronal survival after brain insults, not only via retrograde transport but also through autocrine mechanisms.

Animals↗
PubMed1993

Distribution of alcohol and sorbitol dehydrogenases. Assessment of mRNA species in mammalian tissues.

The tissue distribution of mRNA of alcohol dehydrogenases of classes I, II and III, and sorbitol dehydrogenase, was studied. mRNA from 19 different rat tissues was purified and analyzed by Northern blots, utilizing cDNA probes specific for the four dehydrogenases. Class-I alcohol-dehydrogenase mRNA was shown to be of widespread occurrence, detectable in all tissues including brain, but with pronounced differences in amounts. Hybridization revealed the pattern of occurrence of class-II alcohol-dehydrogenase mRNA to be unique, with transcripts only in the liver, duodenum, kidney, stomach, spleen and testis. Abundant levels of class-III alcohol-dehydrogenase (glutathione-dependent formaldehyde dehydrogenase) mRNA were present in all tissues analyzed, reflecting the general need for scavenging of formaldehyde in physiological cytoprotection. Sorbitol dehydrogenase mRNA was detected in all tissues except small intestine, in agreement with sorbitol resorbtion by passive diffusion in this tissue. In addition, evidence for a sex-specific expression, in the liver, of class-II alcohol dehydrogenase was obtained.

Alcohol Dehydrogenase↗
PubMed1993

Differential regulation of preprotachykinin-A mRNA expression in striatum by excitation of hippocampal neurons.

In this report we have studied the influence of hippocampal neurons on neuropeptide mRNA expression in both dorsal and ventral striatum in the rat. Intrahippocampal unilateral kainic acid injections were performed in control animals and in animals with a unilateral 6-hydroxydopamine-induced dopamine deafferentation of the striatum. In situ hybridization combined with quantitative image analysis was used to study the expression of preprotachykinin A mRNA encoding the neuropeptides substance P and neurokinin A. The 6-hydroxydopamine-induced lesion caused a decrease of preprotachykinin A mRNA levels in the ipsilateral dorsal striatum and in both sides of the ventral striatum. In normal rats, the intrahippocampal kainic acid injection caused a twofold increase in preprotachykinin A mRNA in the limbic parts of the striatum, which are innervated by the hippocampus. No effect of the kainic acid injection was seen in the lateral parts of the dorsal striatum, a region which does not appear to be innervated by the hippocampus. Animals with a 6-hydroxydopamine lesion showed a similar kainic acid-mediated increase in preprotachykinin A mRNA in parts of the ventral striatum. In the dopamine-lesioned dorsal striatum and ventral striatum the decreased preprotachykinin A mRNA levels were normalized by the intrahippocampal kainic acid injection. These results show that kainic acid-mediated excitation of hippocampal neurons causes a dopamine-independent induction of preprotachykinin A mRNA expression in parts of the ventral striatum, and reverses the dopamine deafferentation-induced decrease of preprotachykinin A mRNA in both dorsal and ventral striatum. Combined, our results suggest that hippocampal neurons can regulate preprotachykinin A mRNA expression in both the ventral and the dorsal striatum.

Animals↗
PubMed1993

Characterization of glial trkB receptors: differential response to injury in the central and peripheral nervous systems.

In situ hybridization on sections from the adult rat peripheral and central nervous systems demonstrated that trkB mRNA was expressed not only by neurons but also by cells in central nervous system white matter as well as by Schwann cells in the sciatic nerve. In situ hybridization with an oligonucleotide complementary to the trkB tyrosine kinase domain could only demonstrate mRNA in neurons, indicating expression of truncated trkB receptors lacking the tyrosine kinase domain by glial cells. RNA blot analysis was performed on separately cultured central nervous system glial cells to study which cell types express trkB mRNA. Several transcripts encoding truncated trkB receptors were expressed at high levels in O-2A progenitors, astrocytes, and oligodendrocytes, but not trkB mRNA could be detected in microglia. The expression of trkB mRNA by glial cells in vivo was also investigated after injury; strongly elevated levels of mRNA encoding truncated receptors were detected in the glial scar formed after an incision in the spinal cord dorsal funiculus. In contrast, in the cut sciatic nerve, trkB mRNA decreased distal to the transection, and by 3 weeks only very low levels of mRNA could be detected. Immunoelectron microscopy located trkB-like immunoreactivity to axons and Schwann cells in the sciatic nerve. The expression of truncated trkB receptors by astrocytes, oligodendrocytes, and Schwann cells and the altered levels in response to injury indicate that glial trkB receptors may serve an important function in the intact and injured nervous system.

Animals↗
PubMed1993

Widespread and developmentally regulated expression of neurotrophin-4 mRNA in rat brain and peripheral tissues.

The neurotrophin gene family includes four structurally related proteins with neurotrophic activities. Two of them, nerve growth factor and brain-derived neurotrophic factor (BDNF), have been studied in detail and information has recently emerged on the expression and function of the third member, neurotrophin-3. In contrast, little information is available on neurotrophin-4 (NT-4), the most recently isolated member of this family. In this report we have used a sensitive RNAase protection assay to analyse the developmental expression of NT-4 mRNA in the rat brain and in 12 different rat peripheral organs. In heart, liver and muscle plus skin NT-4 mRNA levels were maximal at embryonic day (E) E13 (the earliest time point tested), with reduced levels at later times of development. In lung, kidney and thymus similar levels were seen from E13 to postnatal day (P) 1, with reduced levels in the adult. In testis, ovary and salivary gland NT-4 mRNA was detected at E16 with a peak shortly after birth. During brain development, NT-4 mRNA was maximal at E13 followed by a decrease around birth, after which the level increased. The postnatal increase of NT-4 mRNA was also seen in cerebral cortex and brain stem analysed separately, while in the hippocampus similar levels were found from P1 to adulthood. NT-4 mRNA was detected in all ten adult rat brain regions analysed with only small regional variations, being highest in pons-medulla, hypothalamus, thalamus and cerebellum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Immunohistochemical localization of calpains and calpastatin in the rabbit eye.

The localization of the two Ca-activated extralysosomal proteases m-calpain and mu-calpain in the eye of the adult rabbit was examined by immunohistochemistry, using poly- and monoclonal antibodies against the corresponding rabbit antigens. Immunoreactivity against the two forms of calpains was observed in the epithelial cells on the external and internal surface of the cornea as well as in the epithelial cells covering the iris and ciliary body. The sclera and choroid layers showed a relatively weak immunoreactivity. Using anti m-calpain antibodies, the pigment epithelium in the retina was heavily labelled as well as the outer and inner plexiform layers. The other and inner borders of the Müller cells were clearly labelled. The outer segments of the receptor cells showed a strong immunoreactivity for both mu-calpain and m-calpain. Labelling was also observed in the retinal ganglion cells and in the nerve fiber layer. The immunohistochemical localization of calpastatin, an endogenous inhibitor of both m- and mu-calpain was also examined. A high level of calpastatin immunoreactivity was observed in the outer segments of the receptor cells. The results may be compatible with a role for calpains, especially m-calpain, in the secretory/phagocytic process and as modulators of the cytoskeleton in cell processes.

Animals↗
PubMed1993

Coexpression of messenger RNA for TRK protooncogene and low affinity nerve growth factor receptor in neuroblastoma with favorable prognosis.

Nerve growth factor (NGF), essential for differentiation and survival of sympathetic neurons is suggested to play a role in differentiation or regression of neuroblastoma. Expression of mRNA for the trk protooncogene, encoding a tyrosine kinase receptor essential for functional NGF signal transduction, and mRNA for the low affinity NGF receptor (LNGFR) was examined in 45 neuroblastomas and 3 benign ganglioneuromas using Northern blot analysis. Expression of trk mRNA and LNGFR mRNA correlated with young age, favorable clinical stages, and absence of N-myc amplification. All children (n = 19) with neuroblastomas coexpressing mRNA for trk and LNGFR are alive 8-84 months from diagnosis, regardless of age and stage. In contrast, no child (n = 15) with tumor lacking trk mRNA is alive without disease. Three subsets of patients were distinguished, one favorable (trk+, LNGFR+, n = 19, 100% survival probability), one intermediate (trk+, LNGFR-, n = 11, 62.3% survival probability), and one unfavorable (trk-, LNGFR +/-, n = 15, 0% survival probability, P < 0.001). In widespread neuroblastoma stage IVS prone to spontaneous regression, three tumors coexpressing trk and LNGFR mRNAs regressed after no or minimal therapy while the remaining tumor expressing trk but not LNGFR mRNA progressed to a fatal outcome. It is concluded that neuroblastomas coexpressing mRNA for both NGF receptor subtypes are favorable tumors likely to differentiate or regress spontaneously or respond to conventional therapy. It is further hypothesized that loss of functional NGF receptors is an important step in tumorigenesis of undifferentiated malignant childhood neuroblastoma. For these unfavorable tumors current therapy remains futile and first-line innovative therapy is justified.

Child, Preschool↗