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P Strömberg

Publications and source records attributed to P Strömberg.

At least 19 recordsLinked to original sources
PubMed2002

Identification and characterisation of two allelic forms of human alcohol dehydrogenase 2.

The human alcohol dehydrogenase system is comprised of multiple forms that catalyse the oxidation/reduction of a large variety of alcohols and aldehydes. A transition that results in an Ile308Val substitution was identified in the human ADH2 gene by single-strand conformation polymorphism analysis. Screening a Swedish population revealed that Val308 was the most frequent allele (73%), and site-directed mutagenesis was used to obtain both allelozymes, which were expressed in Escherichia coli for characterisation. Thermostability was assayed by activity measurements and circular dichroism spectroscopy. The results showed that the 308Val substitution decreases protein stability, as compared to the Ile308 variant, an effect also demonstrated during prolonged storage. Ethanol, octanol, 12-hydroxydodecanoic acid and all-trans retinol were used as model substrates and, generally, slightly higher Km values were observed with Val at position 308. Finally, homology modelling, from mouse ADH2, further supported the decreased stability of the Val308 variant and located position 308 in the subunit interface of the molecule and in the vicinity of the active-site pocket entrance. In conclusion, the Ile308Val substitution represents a novel functional polymorphism within the human alcohol dehydrogenase gene cluster that may affect the metabolism of ethanol and other substrates.

Alcohol Dehydrogenase↗
PubMed2001

Class II alcohol dehydrogenase (ADH2)--adding the structure.

Class II alcohol dehydrogenase (ADH2) represents a highly divergent class of alcohol dehydrogenases predominantly found in liver. Several species variants of ADH2 have been described, and the rodent enzymes form a functionally distinct subgroup with interesting catalytic properties. First, as compared with other ADHs, the catalytic efficiency is low for this subgroup. Second, the substrate repertoire is unique, e.g. rodent ADH2s are not saturated with ethanol as substrate, and while omega-hydroxy fatty acids are common substrates for the human ADH1-ADH4 isoenzymes, including ADH2, these compounds function as inhibitors rather than substrates. The recently determined structure of mouse ADH2 reveals a novel substrate-pocket topography that accounts for the observed substrate specificity and may, therefore, be important for the exploration of orphan substrates of ADH2. It is possible to improve the catalytic efficiency of mouse ADH2 by an array of mutations at position 47. Residue Pro47 of the wild type ADH2 enzyme seems to strain the binding of coenzyme, which prevents a close approach between the coenzyme and substrate for efficient hydrogen transfer. Based on crystallographic and mechanistic investigations, the effects of residue replacements at position 47 are multiple, affecting the distance for hydride transfer, the pK(a) of the bound alcohol substrate as well as the affinity for coenzyme.

Alcohol Dehydrogenase↗
PubMed2001

Functional polymorphism in the alcohol dehydrogenase 3 (ADH3) promoter.

The ADH3 gene encodes alcohol dehydrogenase 3 (ADH3)/glutathione-dependent formaldehyde dehydrogenase, the ancestral and most conserved form of alcohol dehydrogenase. ADH3 is expressed in all tissues examined and the enzyme is essential for formaldehyde scavenging. We have screened the promoter region including exon 1 and exons 5, 6 and 7 of the ADH3 gene for allelic variants. Using 80 samples of genomic DNA from Swedes as template, the various parts of the gene were PCR amplified and subsequently analyzed on single strand conformation polymorphism (SSCP) gels. No abnormal migration patterns could be detected by SSCP analysis of exons 5, 6 and 7 while for the promoter region, a large number of the samples displayed differences in SSCP gel migration patterns. Cloning and sequence analysis revealed four possible base pair exchanges in the promoter region. Two transitions were found at position -197 and -196, GG --> AA, one at position -79, G --> A and finally, close to the transcription start site, a fourth transition was found at position +9, C --> T. An allele specific PCR method was developed and allele frequencies were determined in three populations: Chinese, Spanish and Swedish. GG-197,-196 and AA-197,-196 alleles were common in all three populations, G-79 and A-79 were common in Swedes and Spaniards but only A-79 was found among Chinese. T+9 was the most rare allele with an allele frequency of 1.5% in Swedes. Finally, promoter activity assessments and electrophoretic mobility shift assays demonstrated that the C+9 --> T+9 exchange resulted in a significant transcriptional decrease in HeLa cells and a decreased binding of nuclear proteins. These base pair exchanges may have an effect on the expression of the enzyme and thereby influence the capacity of certain individuals to metabolize formaldehyde.

5' Untranslated Regions↗
PubMed2000

Human class V alcohol dehydrogenase (ADH5): A complex transcription unit generates C-terminal multiplicity.

The human ADH5 gene was reported to lack the last exon compared to other mammalian ADHs and consequently should be expressed as a truncated protein. Here we show with PCR amplification of 3'-cDNA ends that the ADH5 gene harbors the "missing" exon. Besides a cDNA identical to the published sequence, we found full-length transcripts that contained additional codons for eight amino acid residues. Northern blot analysis established the full-length variant as the major transcript with the strongest signal from adult liver. Sequence analysis of genomic DNA confirmed that the ADH5 gene displays composite internal/terminal exons, which can be differentially processed; i.e., 3'-end generation is a result of competition between polyadenylation and splicing.

Alcohol Dehydrogenase↗
PubMed1999

A novel subtype of class II alcohol dehydrogenase in rodents. Unique Pro(47) and Ser(182) modulates hydride transfer in the mouse enzyme.

Mice and rats were found to possess class II alcohol dehydrogenases with novel enzymatic and structural properties. A cDNA was isolated from mouse liver and the encoded alcohol dehydrogenase showed high identity (93.1%) with the rat class II alcohol dehydrogenase which stands in contrast to the pronounced overall variability of the class II line. The two heterologously expressed rodent class II enzymes exhibited over 100-fold lower catalytic efficiency (k(cat)/K(m)) for oxidation of alcohols as compared with other alcohol dehydrogenases and were not saturated with ethanol. Hydride transfer limited the rate of octanol oxidation as indicated by a deuterium isotope effect of 4.8. The mutation P47H improved hydride transfer and turnover rates were increased to the same level as for the human class II enzyme. Michaelis constants for alcohols and aldehydes were decreased while they were increased for the coenzyme. The rodent class II enzymes catalyzed reduction of p-benzoquinone with about the same maximal turnover as for the human form. This activity was not affected by the P47H mutation while a S182T mutation increased the K(m) value for benzoquinone 10-fold. omega-Hydroxy fatty acids were catalyzed extremely slow but functioned as potent inhibitors by binding to the enzyme-NAD(+) complex. All these data indicate that the mammalian class II alcohol dehydrogenase line is divided into two structurally and functionally distinct subgroups.

Alcohol Dehydrogenase↗
PubMed1998

An attempt to transform class characteristics within the alcohol dehydrogenase family.

Human class I alcohol dehydrogenase was mutated at positions 57 and 115, exchanging for Asp and Arg respectively, in an attempt to introduce glutathione-dependent formaldehyde dehydrogenase characteristics. In addition, class III alcohol dehydrogenase, identical to glutathione-dependent formaldehyde dehydrogenase, was mutated at position 115, introducing Ser or Lys. The attempted class transformation was partly successful considering a higher affinity for 12-hydroxydodecanoate and a lower affinity for ethanol that was monitored for the class I mutant. However, the class I mutant displayed neither glutathione-dependent formaldehyde dehydrogenase activity nor fatty acid activation of alcohol oxidation. Interestingly, both class III mutants showed reduced activities for S-hydroxymethylglutathione and 12-hydroxydodecanoate through increased Km, values. Overall results show that it is not possible, by single point mutations, to completely transform enzyme characteristics between these two classes of alcohol dehydrogenase.

Alcohol Dehydrogenase↗
PubMed1989

Comparison of ketoprofen and naproxen in the treatment of dysmenorrhoea, with special regard to the time of onset of pain relief.

In a double-blind, crossover study in 39 women with dysmenorrhoea, the effects of oral treatment with single doses of 100 mg ketoprofen and 500 mg naproxen were compared with regard to time for onset of pain relief and overall effect on symptoms. Assessments of pain severity using a visual analogue scale and an activity-related scale were made at 15-minute intervals for 2.5 hours. The results showed that ketoprofen was significantly more effective at 60 and 45 minutes, respectively, after intake of medicine and the differences remained significant until 120 and 105 minutes, respectively. Reduction in original pain by 50%, the patient's view on the overall effect after each treatment as well as a comparison of effects at the end of the study all differed significantly in favour of ketoprofen. No significant differences were found between treatments in the need for additional analgesic therapy after the 2-hour observation period or in the incidence of side-effects, which was low with both medications. It is suggested that ketoprofen could have a therapeutic advantage over naproxen, particularly in patients in whom menstrual pain develops rapidly.

Adolescent↗
PubMed1987

Inhibition of uterine contractions of premature labour with an oxytocin analogue. Results from a pilot study.

A competitive inhibitor of the action of oxytocin on the uterus, 1-deamino-2-D-Tyr-(OEt)-4-Thr-8-Orn-oxytocin, was studied for the first time in 13 patients with established, uncomplicated premature labour. Intravenous infusion of 10-100 micrograms/min of the analogue was given for 1-10 h and the effect was monitored by external cardiotocography. In all women an inhibition of uterine activity was observed, and in the majority of patients infused with 25 micrograms/min and a total dose of about 5 mg or more of the drug total inhibition of uterine contractions was achieved. There were no effects on the maternal and fetal pulse rates, nor were there any other side-effects. The results of this preliminary study support the concept of an increased concentration of uterine oxytocin receptors being aetiologically important in uncomplicated premature labour. They also suggest that the present oxytocin antagonist could be an interesting therapeutic alternative in the condition, primarily because of the marked selectivity of its effect.

Clinical Trials as Topic↗
PubMed1984

Vasopressin and prostaglandins in premenstrual pain and primary dysmenorrhea.

Both vasopressin and PGF2 alpha are effective uterine stimulants in the non-pregnant human uterus, especially around the onset of menstruation. In order to clarify the relationship of these hormones to menstrual pain, plasma concentrations of vasopressin and two prostaglandin metabolites (15-keto-13,14-dihydro-PGF2 alpha and 11-ketotetranor PGF metabolites) were measured in serial blood samples taken premenstrually and during menstruation. Five women with premenstrual pain gave 7-9 blood samples at intervals of 30 minutes on the day preceding the onset of menstruation. From 5 women with severe primary dysmenorrhea a corresponding series of blood samples were taken during the first day of menstruation. Two groups of 5 women with no symptoms served as controls, either premenstrually or during menstruation. In the women with premenstrual pain the vasopressin concentrations were significantly higher than in the corresponding control group. Even higher and markedly fluctuating vasopressin levels were found in the women with dysmenorrhea who, in general, had more intense pain than the women with premenstrual symptoms. In the group with dysmenorrhea there was also a significant rise in plasma concentration of the PG metabolites. No such increase was seen in the group with premenstrual pain. It is concluded that the pathophysiology of premenstrual pain could imply increased vasopressin secretion. The more severe pain in primary dysmenorrhea seems to be the result of a combined effect of vasopressin and PGF2 alpha.

Adolescent↗
PubMed1983

Inhibition of vasopressin effects on the uterus by a synthetic analogue.

A synthetic analogue, deamino-ethyl-oxytocin, which competitively inhibits vasopressin action on uterine activity both in vitro and in animal experiments was developed. The uterine effect of this analogue was studied during the recording of intrauterine pressure in 16 gynecologically healthy women. Increased uterine activity and dysmenorrhea-like pain was induced by infusing lysine vasopressin in a dose of 0.08 microgram/min. Deamino-ethyl-oxytocin inhibited vasopressin action, the threshold dose being approximately 200 micrograms given as a single intravenous injection for about 20 minutes. When given intranasally the drug was also shown to be effective in inhibiting vasopressin-induced uterine activity and symptoms. These results suggest that deamino-ethyl-oxytocin could be of therapeutic value in primary dysmenorrhea, a condition associated with increased vasopressin secretion.

Adult↗
PubMed1983

Involvement of prostaglandins in vasopressin stimulation of the human uterus.

The involvement of prostaglandins (PG) in the vasopressin (VP) action on the human uterus was investigated in healthy women during three menstruations. Intrauterine pressure was recorded and total pressure area measured. Repeated plasma samples were taken for estimations of arginine(A)- and lysine(L)-VP, 15-keto-13,14-dihydro-PGF2 alpha and 11-ketotetranor PGF metabolites. During the first menstruation LVP was infused in a dose of 0.08 micrograms/min. During the second menstruation the infusion of LVP was repeated with the same dose, but 70 min before infusion the women received an oral dose of 500 mg of naproxen. During the third menstruation PGF2 alpha was administered intravenously in a dose of 25 micrograms/min. LVP infusion per se caused a significant increase in uterine activity and plasma levels of LVP and PG metabolites. When the women were pretreated with naproxen practically the same uterine activity was induced and closely similar plasma levels of LVP were obtained, but the levels of PG metabolites decreased significantly in comparison with the first series of experiments. Infusion of PGF2 alpha caused an increase in uterine activity but no change in the plasma levels of AVP. The results indicate that uterine stimulation with VP is possible without an obligatory last step of PG synthesis and release. The results also support the concept that an elevated VP level in primary dysmenorrhoea may be of aetiological importance and is not just released as a 'stress'-hormone because of the dysmenorrhoeic pain.

Adult↗
PubMed1982

Effect of ovarian steroids on vasopressin secretion.

In normally menstruating women plasma vasopressin concentrations vary with the stage of the cycle and are highest at the time of ovulation and lowest at the onset of menstruation. To determine whether this is the result of changes in the circulating concentrations of ovarian steroids, vasopressin concentrations were determined in six postmenopausal women given oestrogen and progestogen. An increase in plasma oestradiol concentrations to 299 +/- 97.8 pmol/l augmented vasopressin release. Administration of medroxyprogesterone did not influence vasopressin concentrations but when given in combination with oestrogen a fall was observed. Thus it appears that ovarian steroids can modulate vasopressin release.

Animals↗
PubMed1981

Prenatal diagnosis of alpha 1-antitrypsin deficiency by analysis of fetal blood obtained at fetoscopy.

Two women had each borne a child who had alpha 1-antitrypsin (alpha 1AT) deficiency Pi ZZ and who developed liver cirrhosis. In subsequent pregnancies, the women requested prenatal diagnosis. Samples of blood from the two fetuses were obtained at fetoscopy. In a control group of five Pi MM fetuses aborted by hysterotomy, the mean alpha 1AT level was 0.73 g/liter. Of the two fetuses at risk, one had an alpha 1AT concentration calculated as 0.60 g/liter, i.e., within the Pi MZ range. The electrofocusing pattern indicated a heterozygous Pi MZ phenotype which was confirmed at birth. The other fetus at risk had a markedly decreased concentration of alpha 1AT, 0.06 g/liter. Electrofocusing showed a homozygous Pi ZZ phenotype. Analysis of blood from the abortus confirmed these findings and thus the diagnosis of alpha 1AT deficiency. Speculation Most of the alpha 1-antitrypsin in amniotic fluid is derived from the mother. It therefore appears that the only possible way of making a prenatal diagnosis of alpha 1-antitrypsin deficiency is by examination of blood from the fetus. One fetus examined in the present study had an abnormal Z-pattern. This abnormality may indicate a disturbance of fetal liver function already in utero.

Female↗
PubMed1981

Pregnancy specific beta 1 glycoprotein: a comparison of analysis by radioimmunoassay and enzyme linked immunosorbent assay observations on patients with malignant teratoma of testis.

A comparison of serum pregnancy specific beta 1 glycoprotein analysis by enzyme linked immunosorbent assay and radioimmunoassay has been made. Excellent correlation was obtained between the two methods but radioimmunoassay was found to be more precise and to have a lower detection limit than enzyme linked immunosorbent assay. Using the more sensitive radioimmunoassay system, 2 out of 10 control male sera were found to contain detectable levels of pregnancy specific beta 1 glycoprotein. Sequential results are presented on patients with diagnosed malignant teratoma of testis who were undergoing chemotherapy.

Enzyme-Linked Immunosorbent Assay↗
PubMed1981

Variations in plasma concentrations of vasopressin during the menstrual cycle.

Plasma vasopressin concentrations, determined by radioimmunoassay, were followed throughout the menstrual cycle in eight healthy women. The concentrations were found to depend on the day of the menstrual cycle. The mean concentration on day 1 was 0.5 +/- 0.08 (S.E.M.) microunits/ml, while that on days 16-18 was 1.1 +/- 0.16 microunits/ml. These values were significantly (P less than 0.02) different. Vasopressin release in women may thus depend on the hormonal changes during the menstrual cycle.

Adult↗