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H Alho

Publications and source records attributed to H Alho.

At least 73 records · Page 4Linked to original sources
PubMed1997

Unidentified antioxidant defences of human plasma in immobilized patients: a possible relation to basic metabolic rate.

Plasma total peroxyl radical scavenging capacity was studied in terminal patients who were chronically immobilized because of an acute (stroke) or chronic neurodegenerative disease (Alzheimer's disease). A luminometric assay was used to measure total antioxidant capacity (TRAP). The immobilized patients showed significant decrease in TRAP primarily because of a decrease in the concentration of unknown antioxidants. Our results suggest that human plasma may contain unknown antioxidants, the regulation of which could be related to the basic metabolic rate.

Aged↗
PubMed1996

Reduction of GABAergic transmission and alterations in behavior after 6-OHDA treatment of rats.

We studied the effects of neonatal administration of 6-hydroxydopamine (6-OHDA) upon gamma-aminobutyric acid (GABA) and noradrenergic neurotransmission in the developing rat brain. After 6-OHDA administration tyrosine hydroxylase (TH) immunolabelling revealed more than 70% loss of catecholaminergic terminals in cortex. Glutamic acid decarboxylase (GAD) immunolabelling showed that the intensity of staining and the density of labelled terminals were decreased by approximately 50% in the prefrontal cortex of 6-OHDA treated animals, but in visual and somatosensory zones there was no difference between lesioned and control cortex. The open field test revealed an altered development of the searching activity after neonatal 6-OHDA injections. A significant difference was found between 6-OHDA treated and control rats in searching, orienting and skills performance. Our results indicate that the behavioral changes observed in young rats after 6-OHDA treatment may be reflections not only of reduced catecholaminergic transmission but also of GABAergic disturbance, occurring in the frontal cortex.

Animals↗
PubMed1996

Is there an unidentified defence mechanism against infection in human plasma?

The total peroxyl radical scavenging capacity (TRAP) of human plasma was measured from pneumonia patients and controls. TRAP and its main components, ascorbic acid, alpha-tocopherol, uric acid or protein thiol groups, were unaltered, but the concentration of unidentified antioxidants in pneumonia patients was significantly reduced. Our results indicate that human plasma may contain so far unidentified antioxidants depleted in infection.

Adult↗
PubMed1996

The effect of ascorbate and ubiquinone supplementation on plasma and CSF total antioxidant capacity.

Free radicals are thought to be involved in the onset of neuronal disturbances such as Alzheimer's disease, Parkinson's disease, and neuronal ceroid lipofuscinosis. It is also assumed that they play a role in cerebral injury caused by ischemia or trauma. Plasma and cerebrospinal fluid (CSF), Total (peroxyl) Radical-trapping Antioxidant Parameter (TRAP), and the known antioxidant components of TRAP, for instance, ascorbic acid, uric acid, protein sulfhydryl groups, tocopherol, and ubiquinol were analyzed and the remaining unidentified fragment was calculated in five healthy volunteers before and after 4 weeks of ascorbate and ubiquinone (Q-10) supplementation. In CSF, TRAP was significantly lower than in plasma. The major contributor to plasma's antioxidant capacity was uric acid (UA), whereas in CSF it was ascorbic acid (AA). In CSF, AA concentrations were four times higher than in plasma. Oral supplementation of AA (500 mg/d first 2 weeks, 1,000 mg/d following 2 weeks) and Q-10 (100 mg/d first 2 weeks, 300 mg/d following 2 weeks) induced a significant increase in plasma AA and Q-10. Surprisingly, in spite of the high lipophilicity of Q-10, its concentration did not change in CSF. The supplementation of AA increased its concentration in CSF by 28% (p < .05). However, the increase in AA did not result in an increase in CSF TRAP. This indicates that AA had lost one-third of its radical trapping capacity as compared to that in plasma. The facts that AA is the highest contributor to CSF TRAP and its effect on TRAP is concentration dependent could indicate that the peroxyl radical-trapping capacity of CSF is buffered by AA.

Adult↗
PubMed1995

Expression of peripheral-type benzodiazepine receptor and diazepam binding inhibitor in human astrocytomas: relationship to cell proliferation.

The expression of peripheral-type benzodiazepine receptor (PBR) and diazepam binding inhibitor (DBI) were studied in human astrocytic tumors using immunocytochemistry and in situ hybridization. Both PBR and DBI were prominently expressed in neoplastic cells, whereas in normal brain their amount was low or undetectable. Immunocytochemical double staining demonstrated that PBR and DBI were present in the same cells, suggesting that DBI may act in an autocrine manner in these cells. Analysis of 86 cases showed that PBR expression was statistically significantly associated with tumor malignancy grade (P = 0.004) and the proliferative index as determined by immunocytochemistry with the MIB-1 antibody (P = 0.004). Patients having tumors with high levels of PBR-immunoreactive cells had a shorter life expectancy than patients whose tumors showed lower PBR contents (P = 0.024). In conclusion, these results show that PBR expression is higher in neoplastic cells than in normal brain tissue. They also suggest that PBR immunocytochemistry might be useful in evaluating malignancy in brain tumors.

Adolescent↗
PubMed1995

The characterization of two diazepam binding inhibitor (DBI) transcripts in humans.

We have investigated the expression of diazepam binding inhibitor (DBI) (also called acyl-CoA-binding protein or endozepine) transcripts in different human tissues and tissue culture cell lines by reverse-transcriptase assisted PCR and RNase protection assay. Two different DBI transcripts capable of encoding polypeptides of 86 and 104 amino acids were detected in all the human tissues and cell lines studied. The transcript coding for the 86 amino acid DBI polypeptide was found to represent the majority of the total DBI transcript pool.

Amino Acid Sequence↗
PubMed1995

The role of coenzyme Q-10 in aging: a follow-up study on life-long oral supplementation Q-10 in rats.

The essential role of coenzyme Q--ubiquinone--in biological energy transduction is well established. Reduced Q--ubiquinol--has also been shown to act as an antioxidant and to decrease the action of free radicals, which in turn could cause damage to structural lipids or proteins. The accumulation of lipopigments during aging in several peripheral organs and in the nervous system is considered to be related to the peroxidation of unsaturated fatty acids. An age-related decline of Q-10 has been suggested to occur in man and rats. In this study we followed the effects of life-long oral supplementation of coenzyme Q-10 on the development and life-span and pigment accumulation in peripheral tissues and the nervous system of laboratory rats. The Q-10 supplemented group showed a significant increase in Q-10 in plasma and liver, while it was unchanged in other tissues. There was no significant difference between the two groups in the development and mortality of the animals. No differences were observed in lipopigment accumulation. Our results indicate that in rats, life-long supplementation of Q-10 has no beneficial effects on life-span or pigment accumulation.

Administration, Oral↗
PubMed1995

Increased expression of diazepam binding inhibitor in human brain tumors.

Benzodiazepines, which are in extensive clinical use, can regulate neoplastic growth via benzodiazepine receptors. We have studied the expression of the diazepam binding inhibitor (DBI) polypeptide, a putative endogenous ligand for benzodiazepine receptors in normal and pathological human brain. In normal brain, DBI immunoreactivity (IR) and mRNA were detected in all brain areas, with the highest levels in the cerebellum, amygdala, and hippocampus. In light and electron microscope immunohistochemistry, DBI-IR was only detected in glial and ependymal cells. In brain tumors, such as astrocytomas, glioblastomas and medulloblastomas, a much higher content of DBI-IR and -mRNA was found in normal tissues. The highest level of DBI expression was found in the most anaplastic tumors. DBI-IR was virtually undetectable in meningiomas and pituitary adenomas. The high expression of DBI in brain tumors might play a role in the neoplastic growth of glial cells via the mitochondrial benzodiazepine receptor, or it may be involved in the regulation of the high energy consumption of these tumors via acyl-CoA metabolism.

Adolescent↗
PubMed1994

N-methyl-D-aspartate receptor-induced translocation of protein kinase C to the nucleus in rat cerebellar slices.

Rat cerebellar slices were incubated in absence and presence of N-methyl-D-aspartate and then used to prepare a purified nuclear fraction. The purity of the nuclear fraction was assessed by electron microscopy and measurements of Na+, K(+)-ATPase activity. The presence of protein kinase C in nuclear fractions was measured by [3H]phorbol dibutyrate binding. Treatment of cerebellar slices with N-methyl-D-aspartate caused a significant, two-fold increase in the density of nuclear [3H]phorbol dibutyrate binding sites, indicating the translocation of protein kinase C to the nuclear fraction. The effect of N-methyl-D-aspartate was prevented by the presence of the N-methyl-D-aspartate receptor antagonist (+)5-methyl-10,11-dihydro-5H-dibenzocyclohepten-5,10-imine maleate (MK-801). These results suggest a possible role for protein kinase C in mediating N-methyl-D-aspartate-induced nuclear events.

Animals↗
PubMed1994

Tissue-specific expression of the diazepam-binding inhibitor in Drosophila melanogaster: cloning, structure, and localization of the gene.

The diazepam-binding inhibitor (DBI; also called acyl coenzyme A-binding protein or endozepine) is a 10-kDa polypeptide found in organisms ranging from yeasts to mammals. It has been shown that DBI and its processing products are involved in various specific biological processes such as GABAA/benzodiazepine receptor modulation, acyl coenzyme A metabolism, steroidogenesis, and insulin secretion. We have cloned and sequenced the Drosophila melanogaster gene and cDNA encoding DBI. The Drosophila DBI gene encodes a protein of 86 amino acids that shows 51 to 56% identity with previously known DBI proteins. The gene is composed of one noncoding 5' and two coding exons and is localized on the chromosomal map at position 65E. Several transcription initiation sites were detected by RNase protection and primer extension experiments. Computer analysis of the promoter region revealed features typical of housekeeping genes, such as the lack of TATA and CCAAT elements. However, in its low GC content and lack of a CpG island, the region resembles promoters of tissue-specific genes. Northern (RNA) analysis revealed that the expression of the DBI gene occurred from the larval stage onwards throughout the adult stage. In adult flies, DBI mRNA and immunoreactivity were detected in the cardia, part of the Malpighian tubules, the fat body, and gametes of both sexes. Developmentally regulated expression, disappearing during metamorphosis, was detected in the larval and pupal brains. No expression was detected in the adult nervous system. On the basis of the expression of DBI in some but not all tissues with high energy consumption, we propose that in D. melanogaster, DBI is involved in energy metabolism in a manner that depends on the substrate used for energy production.

Amino Acid Sequence↗
PubMed1994

Expression of mitochondrial benzodiazepine receptor and its putative endogenous ligand diazepam binding inhibitor in cultured primary astrocytes and C-6 cells: relation to cell growth.

A recognition site for benzodiazepines structurally different from that linked to the gamma-aminobutyric acid receptor subtype A or the "central type" benzodiazepine receptor has been located mainly in the outer membranes of mitochondria and designated mitochondrial benzodiazepine receptor (MBR). A putative endogenous ligand for MBR is the peptide, diazepam binding inhibitor (DBI), which inhibits benzodiazepine ligand binding in mitochondrial membranes. In this study, DBI- and MBR-like immunoreactivities (LI) were examined at the cellular and ultrastructural levels, and their changes during cell growth were followed in rat primary cerebellar astroglial and C-6 cell cultures. During the early stages of the cultures (7-14 days in vitro), MBR and DBI were expressed virtually in all astrocytes and C-6 cells of the cultures. The highest MBR/DBI immunoreactivity was observed in dividing cells. When the astrocytes had formed a confluent layer (21 days in vitro), MBR staining intensity was significantly decreased. Electron microscopic analysis demonstrated an even distribution of DBI-LI throughout the cytoplasm, while MBR-LI was mainly observed in a close association with the outer mitochondrial membranes. However, dividing cells also displayed strong MBR immunoreactivity in endoplasmic reticulum, nuclear membranes, and centrioles. Treatment of the confluent cultures with MBR ligands PK 11195 and Ro 5-4864 at nanomolar concentrations increased the density of MBR-LI and the progesterone content in the medium 2-3-fold over the basal levels. These results demonstrate a close association between DBI and mitochondrial benzodiazepine receptors and lend support to the theory that they have a possible role in the regulation of steroid production. The relation of MBR and DBI expression to cell growth and division suggests a novel role for these elements in the regulation of important intracellular events.

Amino Acid Sequence↗
PubMed1993

Cloning and tissue-specific functional characterization of the promoter of the rat diazepam binding inhibitor, a peptide with multiple biological actions.

Diazepam binding inhibitor (DBI) is a 10-kDa polypeptide that regulates mitochondrial steroidogenesis, glucose-induced insulin secretion, metabolism of acyl-CoA esters, and the action of gamma-aminobutyrate on GABAA receptors. To investigate the regulation of DBI gene expression, three positive clones were isolated from a rat genomic library. One of them contained a DBI genomic DNA fragment encompassing 4 kb of the 5' untranslated region, the first two exons, and part of the second intron of the DBI gene. Two other overlapping clones contained a processed DBI pseudogene. Several transcription initiation sites were detected by RNase protection and primer extension assays. Different tissues exhibited clear differences in the efficiencies of transcription startpoint usage. Transient expression experiments using DNA fragments of different length from the 5' untranslated region of the DBI gene showed that basal promoter activity required 146 bp of the proximal DBI sequence, whereas full activation was achieved with 423 bp of the 5' untranslated region. DNase I protection experiments with liver nuclear proteins demonstrated three protected regions at nt -387 to -333, -295 to -271, and -176 to -139 relative to the ATG initiation codon; in other tissues the pattern of protection was different. In gel shift assays the most proximal region (-176 to -139) was found to bind several general transcription factors as well as cell type-restricted nuclear proteins which may be related to specific regulatory patterns in different tissues. Thus, the DBI gene possesses some features of a housekeeping gene but also includes a variable regulation which appears to change with the function that it subserves in different cell types.

Animals↗
PubMed1993

Expression of diazepam-binding inhibitor peptide in human skin: an immunohistochemical and ultrastructural study.

Human diazepam binding inhibitor (DBI) was originally isolated from the brain and subsequently found to be present in several peripheral tissues. The various physiologic effects recently attributed to DBI include acting as an endogenous ligand for the central and peripheral (mitochondrial) benzodiazepine receptors. The present work provides, for the first time, evidence of DBI immunoreactivity in skin. DBI immunoreactivity was found in the epidermis, in the eccrine sweat and in sebaceous glands. Ultrastructurally, DBI was distributed throughout the cytoplasm. Although the physiologic role of DBI in skin is unknown, our results indicate that DBI may serve as an endogenous ligand for mitochondrial benzodiazepine receptors. Its activity could be related to the regulation of lipid and cholesterol synthesis in keratinocytes and sebaceous glands and to the secretion of sweat in sweat glands.

Adolescent↗
PubMed1993

Ultrasound-amplified immunohistochemistry.

We describe a novel technique for improving the sensitivity of immunofluorescence staining by use of ultrasonic irradiation. Free-floating vibratome sections from rat cerebellum were incubated with primary antiserum and simultaneously were briefly exposed to ultrasound (US) in a conventional ultrasound bath. After the US treatment, a conventional immunohistochemical method was employed. Two different antisera and two conventional immunohistochemical detection systems were tested. In all cases a 10-20-sec US treatment strengthened immunoreactivity considerably. Irradiated samples showed a good morphology compared with non-irradiated sections. Our results demonstrate that with ultrasonic treatment the dilutions of primary antibodies can be increased and the incubation times of primary antisera can be reduced. The ultrasonic method described here requires no special equipment. It is easy, reproducible, and it can be considered a new method for the enhancement at immunohisto- and cytochemical staining of free-floating vibratome sections.

Animals↗
PubMed1993

Topology of two DBI receptors in human lymphocytes.

High-affinity binding sites for the isoquinoline carboxamide PK 11195 and 4'-chlorodiazepam (4'CD) in human lymphocytes are recognized by two putative endogenous ligands: diazepam binding inhibitor (DBI) and protoporphyrin IX. We have now demonstrated that several synthetic DBI peptides--analogues to naturally processed human DBI (H-DBI) fragments--differ from protoporphyrin IX in the manner in which they displace [3H]PK 11195 and [3H]4'CD from binding sites associated with intact and cell-free lymphocyte preparations. In particular, the peptide fragments DBI37-80 and DBI37-70 displaced [3H]PK 11195 and [3H]4'CD with higher affinity from their binding sites on intact lymphocytes (Ki approximately 3-5 microM) than from the sites in the cell-free preparation (Ki approximately 20 microM). In contrast, protoporphyrin IX displaced [3H]PK 11195 and [3H]4'CD with higher affinity in the cell-free preparation (Ki - 0.4 microM) than in intact lymphocytes (Ki > 50 microM). Because DBI peptide fragments and protoporphyrin IX do not readily penetrate the plasma membrane of lymphocytes, our results suggest the existence of binding sites located both on the external face of the plasma membrane and intracellularly. The plasma membrane binding sites, recognized essentially only by DBI fragments, are termed here plasma membrane DBI receptors (PDRs). In contrast, the intracellular binding sites, recognized by both DBI fragments and protoporphyrin IX, are presumably located on mitochondria and are termed mitochondrial DBI receptors (MDRs). Immunohistochemical electronmicroscopic studies with antibodies to the synthetic peptide fragments 62-76 of the rat MDR support the hypothesis that PDRs are expressed on lymphocyte plasma membranes.

Amino Acid Sequence↗