A TaqI RFLP at the human renal kallikrein (KLK1) locus.
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Chromosome Mapping↗
Biomedical subjects
K Berg
Publications and source records attributed to K Berg.
The photodegradation of porphyrins in cells can be used to estimate the lifetime of singlet oxygen.
NHIK 3025 cells were incubated with Photofrin II (PII) and/or tetra (3-hydroxyphenyl)porphyrin (3THPP) and exposed to light at either 400 or 420 nm, i.e. at the wavelengths of the maxima of the fluorescence excitation spectra of the two dyes. The kinetics of the photodegradation of the dyes were studied. When present separately in the cells the two dyes are photodegraded with a similar quantum yield. 3THPP is degraded 3-6 times more efficiently by light quanta absorbed by the fluorescent fraction of 3THPP than by light quanta absorbed by the fluorescent fraction of PII present in the same cells. The distance diffused by the reactive intermediate, supposedly mainly 1O2, causing the photodegradation was estimated to be on the order of 0.01-0.02 micron, which corresponds to a lifetime of 0.01-0.04 microsecond of the intermediate in the cells. PII has binding sites at proteins in the cells as shown by an energy transfer band in the fluorescence excitation spectrum at 290 nm. During light exposure this band decays faster than the Soret band of PII under the present conditions. Photoproducts (1O2 etc.) generated at one binding site contribute significantly in the destruction of remote binding sites.
Biodegradation, Environmental↗
Light induced relocalization of sulfonated meso-tetraphenylporphines in NHIK 3025 cells and effects of dose fractionation.
Human cervix carcinoma cells of the line NHIK 3025 were incubated for 18 h with sulfonated meso-tetraphenylporphines (TPPSn where n = 1, 2a, 2o or 4) followed by 1 h in sensitizer-free medium and then exposed to light. The fluorescing fraction of TPPS4, TPPS2o and TPPS2a has recently been shown to be located intracellularly in extracellular granules which are intracellularly localized in a similar pattern as acridine orange-stained granules, assumed to be endosomes and lysosomes (Berg, K., A. Western, J. Bommer and J. Moan. Photochem. Photobiol. 52, 481-487). Light exposure induced a relocalization of TPPS4 from its granular pattern to mainly the nuclear area while TPPS2o and TPPS2a relocalized mainly to cytoplasmic areas. After the light-induced relocalization TPPS4 became less efficient in sensitizing photoinactivation of cells as measured per fluorescing cellbound TPPS4 molecules while TPPS2a and TPPS2o became more efficient. These changes were independent of the extracellular concentration of TPPSn applied to the cells, except for cells incubated with 75 micrograms/mL TPPS4. These cells became more sensitive to light after a light exposure inactivating 20% of the cells. This increased photosensitivity seems to be related to a 2-2.5 fold increase in the amount of fluorescing cellbound TPPS4 induced by the first light exposure.
Biological Transport↗
The occurrence of epilepsy and febrile seizures in Virginian and Norwegian twins.
Twin studies provide an efficient method for examining the importance of genetic and environmental factors in the etiology of disorders such as epilepsy. Population-based twin registries are especially valuable for studies of this type since effects of reporting and self-selection biases on the resulting data are minimized. Among 14,352 twin pairs contained in the Virginia and Norwegian twin panels for whom questionnaire information was available, there was a history of epilepsy in one or both members of 286 pairs; febrile seizures were reported in 257 pairs. Analyses of questionnaire data revealed no significant differences in concordance rates between Virginian and Norwegian twins for either epilepsy or febrile seizures. Probandwise concordance rates for epilepsy were 0.19 in monozygotic twins and 0.07 in dizygotic twins. Analogous rates for febrile seizures were 0.33 (monozygotic) and 0.11 (dizygotic). These results provide further evidence that genetic factors do have a role in the expression of epilepsy and febrile seizures.
Diseases in Twins↗
Lp(a) lipoprotein level and longevity.
Lp(a) lipoprotein forms a distinct class of serum lipoproteins. Its unique immunochemical properties are caused by the Lp(a) polypeptide chain which is attached to apolipoprotein B (apoB) by a disulfide bridge. The level of Lp(a) lipoprotein is under strict genetic control. It is well established that a high level of Lp(a) lipoprotein is a genetic risk factor for atherosclerotic disease, particularly coronary heart disease (CHD). Since cardiovascular disease is one of the major causes of death there should be a shortage of people with genetic determinants of cardiovascular disease in people who are very old and still have adequate physical and mental capacities. The authors have studied Lp(a) lipoprotein levels in 102 persons who were 83 years or older when blood samples were drawn. This study group was a subpopulation of a series comprising 456 persons who had been 80 years or older at intake in an intervention study of old people living at home. Only those without physical or mental incapacities were included in the present study. There was a striking shortage of persons with an Lp(a) lipoprotein level higher than the 75th percentile of the general population in this series of people who had achieved successful ageing. The highest value observed among the old people corresponds to the 88th percentile of the general population. It is highly unlikely that the present observations reflect chance events or fall in Lp(a) lipoprotein levels in people who had higher levels at a younger age. The most likely explanation of our finding is that a sizeable fraction of people with high Lp(a) lipoprotein levels die before reaching a very high age.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
A TaqI RFLP at the EDN1 gene locus.
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Chromosomes, Human, Pair 6↗
Finding the gene(s) for alcoholism.
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Alcoholism↗
A sensitive antiviral neutralization bioassay for measuring antibodies to interferons.
An improved bioassay for measuring neutralizing antibodies to interferons (IFN) is described. The assay is based upon an objective and precise quantification of the viral cytopathic effect. This effect is measured via the dehydrogenase-system in cells, and quantified spectrophotometrically. Virus-infected cells, in contrast to non-infected cells, possess low enzyme activity resulting in low OD signals. This fall in OD can be prevented by the addition of a small, but fixed amount of IFN before the addition of virus. Anti-IFN sera will neutralize the protective effect of IFN. This effect can be quantified by measurement of the reduction in the OD signals. Antibodies to recombinant IFN were found to cross-react with human leukocyte IFN although to a ten-fold lower degree. The assay requires no expensive reagents, it is performed in 96-well microtrays and the results can be measured in an ordinary ELISA scanner. The assay is highly reproducible, yielding inter- and intra-assay variability of less than 10%. The sensitivity is much higher than that reported previously for the CPE technique and that of ELISA techniques.
Animals↗
Risk factor variability and coronary heart disease.
Present attempts to identify genes contributing to coronary heart disease (CHD) risk focus on "candidate genes". With respect to CHD this could be any gene whose protein product is directly or indirectly involved in atherogenesis, thrombogenesis or thrombolysis/fibrinolysis. Genes that exhibit associations with absolute risk factor levels may be referred to as "level genes" to distinguish them from "variability genes", which are genes involved in establishing the framework within which environmental influences may cause risk factor variation. In a series of persons recruited from the Norwegian Twin Panel, confirmatory evidence for level gene effect with respect to apolipoprotein B (apoB) concentration was found with an XbaI polymorphism in DNA at the apoB locus corresponding to residue 2,488 in the mature protein. Evidence for variability gene effect with respect to apoB as well as body mass index emerged with DNA variants in the 3' part of the apoB gene. Level gene effect with respect to apolipoprotein A-I (apoA-I) and high density lipoprotein (HDL) cholesterol as well apparent variability gene effect with respect to total and LDL cholesterol were detected with a DNA polymorphism at the cholesteryl ester transfer protein (CETP) locus. The first example of interaction between normal genes in determining risk factor level was uncovered in analysis of the apolipoprotein E (apoE) polymorphism and a restriction fragment length polymorphism (RFLP) at the low density lipoprotein receptor (LDLR) locus. An LDLR gene identified by presence of a PvuII restriction site eliminated completely the well known effect of the apoE4 allele on cholesterol level. Finally, in families where high Lp(a) lipoprotein level (a well established risk factor for CHD) segregated as a Mendelian trait, very close linkage with an RFLP at the plasminogen locus was established and DNA variation at the LPA locus reflecting varying numbers of a structure homologous to the "kringle IV" region of plasminogen was uncovered.
Alleles↗
Physical and performance characteristics of NCAA Division I football players.
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Adipose Tissue↗
Cellular inhibition of microtubule assembly by photoactivated sulphonated meso-tetraphenylporphines.
This work relates to studies on modes of phototoxicity by sulphonated mesotetraphenylporphines on cultured cells. Toxicity appears to be related to inhibition of microtubule function. Treatment of human cervix carcinoma cells of the line NHIK 3025 incubated for 18 h with meso-tetraphenylporphine sulphonates (TPPSn where n = 2a, 2o or 4) and exposed to light, inhibits multiplication for the first hours after light exposure, a significant fraction of the cells accumulating in mitosis. The maximal number of cells in mitosis after treatment (approximately 20%) is dependent on the fluence but is similar for all three photosensitizers. For the first hours after treatment the mitotic cells were always mainly in metaphase; mainly seen as c-metaphases and three-group metaphases. During this time anaphase and telophase cells were absent or greatly reduced in number. Indirect immunofluorescence staining of beta-tubulin showed that the spindle apparatus of mitotic cells was perturbed in all cases. Results are presented which indicate that photoactivation of TPPSn located on the plasma membrane destroys microtubules in interphase cells and leads to arrest of the cells in mitosis. The localization of the dye which sensitizes the photoinduced perturbation of microtubules is further discussed.
Cell Division↗
Autoantibodies to crude human leucocyte interferon (IFN), native human IFN, recombinant human IFN-alpha 2b and human IFN-gamma in healthy blood donors.
Recently, naturally occurring antibodies to IFN-alpha were discovered in a few systemic lupus erythematosus (SLE) and cancer patients; however, in most patients monitored for anti-IFN antibodies before treatment, no antibodies were found. In an attempt to explain the 'IFN-blocking effect' that we observed in all serum samples we investigated 200 sera from healthy blood donors. We isolated the globulin fraction, and used rabbit anti-human IgG and IgM columns, protein A columns and T-gel affinity chromatography to isolate human IgG and IgM. All sample fractions were tested in a biological IFN neutralization assay by means of a sensitive MTT-assay. We found that normal human serum contained autoantibodies to crude human leucocyte IFN, native human fibroblast IFN, recombinant human leucocyte IFN-alpha 2b and recombinant human IFN-gamma, and that these naturally occurring antibodies were biologically active immunoglobulins of IgG and IgM type. These anti-IFN antibodies were also present in purified human normal immunoglobulin pools. We conclude that all humans have naturally occurring anti-interferon antibodies in their serum, and it is a tempting theory that human cytokines and lymphokines are, at least partly, regulated by immunoglobulins.
Adolescent↗
Inherited quantitative DNA variation in the LPA ("apolipoprotein (a)") gene.
The Lp(a) antigen resides in a polypeptide chain that is attached to apolipoprotein B (apoB) by a disulfide bridge. Recently, cDNA for this polypeptide chain (frequently referred to as the Lp(a) polypeptide chain, Lp(a) apolipoprotein or apolipoprotein (a] was cloned and extensive homology to plasminogen was uncovered. This homology creates significant difficulties in studying DNA variation in the gene (the LPA gene) for this polypeptide and the plasminogen gene. We have studied a variant 2 kilobase (kb) DNA fragment detectable after digestion with the restriction enzyme MspI, which appears to originate from the LPA gene since it is detected by LPA probes but not with plasminogen probes. It is related to the "kringle IV" region of the LPA gene since it is detected with an LPA probe that only contains "kringle IV" repeats. A proportion of people appears to lack (or have an undetectable level of) the 2 kb fragment and there are significant quantitative differences between samples from people who have the fragment. Presence and amount of this fragment appear to segregate in families as a Mendelian trait. This quantitative DNA variation is likely to reflect differences between individuals in number of "kringle IV" repeats at the LPA locus.
Adult↗
Restriction site polymorphism at the LPA (Lp(a) apolipoprotein; apolipoprotein (a)) locus.
A restriction site polymorphism in the Lp(a) apolipoprotein gene (the LPA gene) is reported. The basis for the polymorphism is presence or absence of an MspI restriction site that appears to be 3' to the last kringle IV structure of the gene. The "1" gene (presence of the restriction site) has a frequency of 0.316 and the "2" gene (absence of the restriction site) has a frequency of 0.684. Both members of each of 67 monozygotic (MZ) twin pairs had the same genotype and there was Mendelian segregation of the DNA variants in 40 families with a total of 75 children. There was a lower proportion of people with genotype 1-1 in the top quartile than in the 3 bottom quartiles of the population distribution of Lp(a) lipoprotein levels but the difference did not reach statistical significance.
Apolipoproteins↗
Spinal muscular atrophy type I combined with atrial septal defect in three sibs.
All three children of an unrelated Norwegian couple were born with spinal muscular atrophy (SMA I) as confirmed by autopsy in two of them. Two of the children died at birth, whereas one lived for 7 weeks on support systems that included artificial ventilation. All three children had large atrial septal defects (ASD). One had valvular aortic stenosis. Another had arrhinencephaly and transient pleural effusion which was evacuated during pregnancy. The findings may reflect concurrence of unrelated disorders caused by genetic or environmental factors, segregation of linked genes, pleiotropism or the existence of a previously unknown disease.
Abnormalities, Multiple↗
Gene-gene interaction between the low density lipoprotein receptor and apolipoprotein E loci affects lipid levels.
A restriction fragment length polymorphism (RFLP) at the low density lipoprotein receptor (LDLR) locus, detectable with the restriction enzyme PvuII has been studied in a second series of Norwegian subjects, believed to be representative of the general population. The results confirm the association of normal alleles at the LDLR locus with differences in age- and sex-corrected total and LDL cholesterol. A gene identified as one of the alleles in this RFLP appears to eliminate the effect of the apolipoprotein E4 (apoE4) gene on cholesterol (or its allele must be present for the apoE4 effect on lipid level to manifest itself). The findings in this series substantiate previous indications that normal alleles are of importance in the control of LDLR activity and that normal LDLR alleles contribute to the population variation in cholesterol. Finally, they confirm that an interaction between LDLR and apoE genes contributes to the population variation in total and LDL cholesterol.
Adult↗
A new sensitive bioassay for precise quantification of interferon activity as measured via the mitochondrial dehydrogenase function in cells (MTT-method).
A biological method for precise quantification of interferons has been developed. The method is based upon the dehydrogenase system of the intact target cells, which will normally convert an artificial substrate, MTT, into formazan (blue), which, in turn, can be measured spectrophotometrically. This conversion is greatly reduced by cytocidal viruses in a dose-dependent manner. The protection of target cells by interferon against challenge virus is reflected in a diminished reduction in the production of formazan, thus giving a very precise method for quantification of interferon. The lowest level of detection is around 0.10 international units. The intra- and inter-assay variability appear to be below 10%. The assay, which makes no use of expensive ingredients, is performed in 96-well micro-trays and read in an inexpensive ELISA-scanner.
Biological Assay↗
Intracellular localization of sulfonated meso-tetraphenylporphines in a human carcinoma cell line.
The intracellular localization of meso-tetraphenylporphines sulfonated to different degrees (TPPSn), in a human cervix carcinoma cell line (NHIK 3025), was studied by fluorescence microscopy and fluorescence spectroscopy. After an 18 h incubation, TPPS4, TPPS2a and TPPS2o were localized in extranuclear granules. Studies of cells stained with both TPPS4, and acridine orange, which is known to fluoresce red in lysosomes, indicated that these granules were lysosomes. In addition, a fraction of the cellbound TPPS4, TPPS2a and TPPS2o seems to be associated with the plasma membrane. Fluorescence quenching studies of cells doublestained with acridine orange and TPPS4 indicated that TPPS4 is also localized in the nucleus and in the extralysosomal cytoplasm. The intracellular location of TPPS1 differed from that of the other TPPSns studied: In 6 out of 9 experiments fluorescing extranuclear granules were found. A diffuse fluorescence extending from the perinuclear area was also observed.
Biological Transport↗