Search PubMed⌕ Search

Biomedical subjects

H Persson

Publications and source records attributed to H Persson.

At least 199 records · Page 11Linked to original sources
PubMed1991

Biological and immunological properties of recombinant human, rat, and chicken nerve growth factors: a comparative study.

Biological and immunological properties of recombinant human, rat, and chicken nerve growth factors (NGFs) were studied and compared. Recombinant NGF proteins were produced in a transient expression system using COS cells and levels of secreted NGF protein were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of conditioned media from in vivo [35S]cysteine-labeled cell cultures. Antigenic differences among the three NGFs were studied by immunoblotting and immunoprecipitation of secreted cell products using a rabbit polyclonal antiserum against purified mouse NGF, and by a two-site enzyme immunoassay (EIA) with a monoclonal antibody against mouse NGF. Although all three NGFs were recognized equally well in the immunoblotting, only one-third of the chicken NGF protein could be detected by immunoprecipitation or by the EIA as compared to the rat and human NGFs. Thus, changes in the three-dimensional structure of the NGF molecule are most likely responsible for the antigenic differences between avian and mammalian NGFs. The three NGF proteins were also compared in their ability to displace 125I-mouse NGF from low-affinity NGF receptors on rat pheochromocytoma PC12 cells. Similar displacement curves and values were obtained for each NGF protein, indicating that structural differences among these molecules do not affect low-affinity binding to NGF receptors. Biological activities were studied by the ability of the conditioned media to promote neurite outgrowth from explants of E9 chick sympathetic ganglia and from PC12 cells. Although the rat system showed a slight preference for the homologous molecule, the morphological changes, dose-response curves, and maximal stimulation values obtained with the different NGFs were practically indistinguishable in the chicken bioassay.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed1991

Chronic diarrhoea after radiotherapy for gynaecological cancer: occurrence and aetiology.

The occurrence of chronic diarrhoea was evaluated in 173 consecutive patients previously treated with radiation for gynaecological cancer. A survey of gastrointestinal symptoms showed a high frequency of diarrhoea; 13% of the patients had 21 or more bowel movements a week and 3% had 28 or more. Significantly more patients who had a cholecystectomy were in the group with diarrhoea (chi 2 = 6.26; p less than 0.02). Twenty patients with chronic or intermittent diarrhoea were subject to extended gastrointestinal investigation. Bile acid malabsorption was evaluated by the 75Selenahomocholic acid-taurine test (SeHCAT). Bile acid malabsorption was found in 13 (65%) of the 20 patients further investigated, of whom seven had extremely low whole body retention values, which is consistent with severe malabsorption. The results suggest that bile acid malabsorption is a common cause of diarrhoea after radiation treatment for gynaecological cancer. Bacterial contamination was diagnosed in nine patients (45%) by the [14C]-D-xylose breath test or by the cholyl-[14C]-glycine breath test in combination with a normal test for bile acid malabsorption. All patients with vitamin B-12 deficiency, who were tested for bile acid malabsorption, had low retention times for the SeHCAT (p = 0.05). A significant decline in the frequency of diarrhoea was found after treatment with antibiotics or bile acid sequestrants, or both, in combination with a reduced fat diet.

Adult↗
PubMed1991

Birth-related activation of preprotachykinin-A mRNA in the respiratory neural structures of the rabbit.

The perinatal ontogeny of preprotachykinin-A gene expression was assessed in central respiration-related structures. On the day of birth, there was an enhanced expression of preprotachykinin-A mRNA in the region of the nucleus tractus solitarii, the primary relay station for respiratory and cardiovascular reflexes. This increased expression was also seen in the pups delivered by cesarean section and allowed to breathe for a couple of hours as compared with their littermates, which were not allowed to breathe at all. On the basis of this finding, we suggest that the commencement of continuous breathing at birth, unlike the episodic breathing of fetal life, is associated with the enhanced expression of preprotachykinin-A mRNA in the nucleus tractus solitarii.

Animals↗
PubMed1991

Cure of zygomycosis caused by a lipase-producing Rhizopus rhizopodiformis strain in a renal transplant patient.

A 40-year-old man with renal failure due to membranous glomerulonephritis received a cadaveric renal transplant and immunosuppressive therapy with cyclosporine, azathioprine and steroids. Initially the transplantation was successful. 12 days after the transplantation, however, serous secretion appeared in the wound. Later, black necrosis was seen. Fungal culture showed growth of a zygomycete species. Rhizopus rhizopodiformis, with high in-vitro resistance to amphotericin B, flucytosine, fluconazole, ketoconazole and itraconazole. The MIC value for the allylamine derivative SF86-327 (Exoderil) was 1.6 micrograms/ml. Microscopic examination of sections from a surgical revision showed necrosis of the fat tissue and massive hyphal invasion of the perirenal fat, which contained semi-crystalline material anisotropic as seen in polarized light and characteristically staining with rubeanic acid. These histological data indicate a lipase-induced in-vivo splitting of lipids into fatty acids. In-vitro R. rhizopodiformis showed very high extracellular lipase production. 11 days after initiation of amphotericin B therapy cultures and sections remained positive for rhizopus. Amphotericin B was therefore supplemented with Exoderil orally, cyclosporine and steroids were maintained, and azathioprine was discontinued. The wound granulated, shrank, and healed completely in 10 weeks.

Adult↗
PubMed1991

Poisoning with sodium hypochlorite solution. Report of a fatal case, supplemented with an experimental and clinico-epidemiological study.

A case of fatal poisoning in a 1-year-old girl after ingestion of a household cleanser containing 4.5% sodium hypochlorite (Klorin) in an alkaline solution (pH 12.0) is reported. The forensic medical and toxicological investigations were supplemented by animal studies. These studies indicate that 5, 10, and 15 ml of Klorin/kg body wt given to rats is highly toxic, and that local tissue damage and secondary systemic involvement develops with a severity corresponding to the amount administered. The rats, all of which died, showed various degrees of degeneration and necrosis of the esophagoventricular mucosus membranes, changes analogous to those found at the autopsy of the child. A follow-up investigation of similar cases reported to the Swedish Poison Information Centre, during a limited time, was made to complete the picture.

Accidents↗
PubMed1991

Transient and persistent expression of NT-3/HDNF mRNA in the rat brain during postnatal development.

Neurotrophin-3 (NT-3) is closely related to two known neurotrophic agents, NGF and brain-derived neurotrophic factor (BDNF), and acts upon overlapping, yet distinct, populations of peripheral ganglia. NT-3 mRNA expression in the adult rat brain is largely confined to the hippocampus. In this study, we have used in situ hybridization to examine expression of this novel neurotrophic factor during postnatal development. The striking observation was made that NT-3 mRNA was transiently expressed at high levels in the cingulate cortex during the first 2 weeks of age. In the hippocampus, the adult pattern of expression, in the CA2, medial CA1, and granule layer of the dentate gyrus, was detected at all ages examined. However, there were two major differences in NT-3 mRNA expression in the developing hippocampus: Labeled cells were detected in the hilar region of the dentate gyrus at postnatal day 1 (P1) and 1 week that were absent by 2 weeks of age. Further, the caudal hippocampus, which has a lower intensity of labeling than the rostral region in the adult, was devoid of NT-3-expressing cells in the P1 and 1-week-old rat brain. These data indicate a substantial plasticity in NT-3 mRNA expression and suggest that the spectrum of neurons supported by NT-3 during development is partially different from that in the mature rat brain.

Aging↗
PubMed1990

Preprotachykinin A mRNA expression in the rat brain during development.

Expression of preprotachykinin A (PPT-A) mRNA was analyzed by northern blots using mRNA prepared from rat brain at 12 different developmental stages ranging from embryonic day 15 (E15) to adult. A single PPT-A mRNA of 1.3 kb was detected throughout development. PPT-A mRNA was detected as early as E15 and an approximately 3-fold increase occurred at birth. This amount remained until 3 weeks of age when the level increased, reaching a peak at 5 weeks of age. Adult amounts were approximately 3-fold higher than the levels at birth. The distribution of PPT-A mRNA-expressing cells in rat brain was studied by in situ hybridization on sections from embryonic day 20, postnatal days 4 and 7 as well as adult. Cells expressing PPT-A mRNA were detected in the forebrain at all 4 ages analyzed. However, the hybridization pattern and the labeling intensity varied in different brain regions during development. In cingulate cortex, intense labeling was seen in numerous cells at embryonic day 20 and postnatal days 4 and 7, whereas in the adult cingulate cortex only a few scattered labeled cells were observed. In frontoparietal cortex labeled cells were found from postnatal day 4 to adult, with the highest density of labeled cells at P7. Developmental differences in both the distribution of PPT-A mRNA-expressing cells and the level of PPT-A mRNA expression were also found in caudate-putamen, lateral hypothalamus and amygdala. Thus, our results show several changes in PPT-A mRNA expression during ontogeny, indicating a region and time-specific regulation of PPT-A mRNA expression during brain maturation.

Animals↗
PubMed1990

[Nerve growth factor as a therapeutic agent: transplantation of brain tissue as a possible treatment of neurodegenerative disorders].

An account of experiments focused on the treatment of neurodegenerative disease by means of cell grafts, in which genetically modified cells that release abundant nerve growth factor are described, and their transplantation to the rat brain reported. The cells can survive in the rat brain and exert potent effects on cholinergic neurons both in the host cortex, basal forebrain and striatum, and in tissue grafts.

Animals↗
PubMed1990

Expression of beta-nerve growth factor receptor mRNA in Sertoli cells downregulated by testosterone.

Nerve growth factor (NGF) is synthesized in male germ cells. The NGF receptor (NGFR) mRNA was found in the Sertoli cells of rat testis. Hypophysectomy increased both NGFR mRNA in testis and the number of NGFR hybridizing cells in seminiferous tubules. This was suppressed by treatment with chorionic gonadotropin or testosterone, but not with follicle-stimulating hormone. The NGFR mRNA also increased after destruction of Leydig cells or blocking of the androgen receptor. This suggests that NGF produced by male germ cells regulates testicular function in an androgen-modulated fashion by mediating an interaction germ and Sertoli cells.

Animals↗
PubMed1990

Two-dimensional electrophoresis of membrane proteins: separation of myelin proteins.

A method for two-dimensional electrophoretic separation of myelin proteins is presented. The first dimension consists of isoelectric focusing of lyophilized and delipidated membrane proteins, solubilized in a mixture of the nonionic detergent Triton X-100, the zwitterionic detergent CHAPS, 9 M urea and carrier ampholytes, and incorporated into a slab gel before separation. Subsequent discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed by moulding the isoelectric focusing slab gel with its supporting glass plate into the stacking gel. This method proved to give highly reproducible results since mechanical forces and thus the risk of stretching, folding or rupture of the isoelectric focusing slab gel is minimized. Furthermore, by immunoblotting, the positions of myelin-associated glycoprotein and 2',3'-cyclic nucleotide 3'-phosphodiesterase were established with specific antibodies.

Animals↗
PubMed1990

Structure-function studies of nerve growth factor: functional importance of highly conserved amino acid residues.

Selected amino acid residues in chicken nerve growth factor (NGF) were replaced by site-directed mutagenesis. Mutated NGF sequences were transiently expressed in COS cells and the yield of NGF protein in conditioned medium was quantified by Western blotting. Binding of each mutant to NGF receptors on PC12 cells was evaluated in a competition assay. The biological activity was determined by measuring stimulation of neurite outgrowth from chick sympathetic ganglia. The residues homologous to the proposed receptor binding site of insulin (Ser18, Met19, Val21, Asp23) were substituted by Ala. Replacement of Ser18, Met19 and Asp23 did not affect NGF activity. Modification of Val21 notably reduced both receptor binding and biological activity, suggesting that this residue is important to retain a fully active NGF. The highly conserved Tyr51 and Arg99 were converted into Phe and Lys respectively, without changing the biological properties of the molecule. However, binding and biological activity were greatly impaired after the simultaneous replacement of both Arg99 and Arg102 by Gly. The three conserved Trp residues at positions 20, 75 and 98 were substituted by Phe. The Trp mutated proteins retained 15-60% of receptor binding and 40-80% of biological activity, indicating that the Trp residues are not essential for NGF activity. However, replacement of Trp20 significantly reduced the amount of NGF in the medium, suggesting that this residue may be important for protein stability.

Amino Acid Sequence↗
PubMed1990

Rescue of basal forebrain cholinergic neurons after implantation of genetically modified cells producing recombinant NGF.

Mouse 3T3 fibroblasts were genetically modified by transfection with a mammalian expression vector containing the rat beta-nerve growth factor (NGF) gene. The transfected cell line, designated 3E, contains several hundred copies of the rat NGF gene and secretes high levels of biologically active NGF. Pieces of collagen gel containing the NGF-secreting 3E cells were grafted to the brains of unilaterally fimbria-fornix-lesioned rats. Grafts of the genetically modified NGF-producing cells rescued axotomized basal forebrain cholinergic neurons and significantly reduced cholinergic cell death in the medial septum as compared with rats treated with grafts of the parental 3T3 cells. Grafted fibroblast cells were detected, and rescue effects were noted up to 6 weeks after grafting. Local effects of NGF secreted by grafted cells were also seen at the gel-brain border in the form of sprouting acetylcholinesterase immunoreactive host cortical fibers. We suggest that implantation of genetically modified cells producing NGF may have therapeutic applications in rescuing damaged central cholinergic neurons in senile dementia of the Alzheimer type as well as in providing trophic support for chromaffin tissue grafts in Parkinson's disease.

Acetylcholinesterase↗