PubMed Health⌕ Search

Biomedical subjects

E Andersson

Publications and source records attributed to E Andersson.

At least 19 recordsLinked to original sources
PubMed1992

Temperature, but not photoperiod, influences gonadotropin-releasing hormone binding in the pituitary of the three-spined stickleback, Gasterosteus aculeatus.

Gonadotropin-releasing hormone (GnRH) binding characteristics in pituitaries of stickle-backs under different physiological conditions were studied using D-Arg6-Pro9-salmonGnRH-NEt as labeled ligand. Both males and females displayed marked seasonal changes in the capacity of high-affinity GnRH binding sites; there was a high content in the breeding season (summer) (800-1500 pmol/pituitary) and no detectable high affinity (< 150 pmol) binding in late winter-early spring. The binding capacity was lower in postbreeding fish (ca. 400 pmol/pituitary in females, ca. 900 pmol in males) than in breeding fish (females: ca. 1850, males ca. 1400 pmol). GnRH binding sites were also studied in fish exposed to long and short photoperiod in combination with high and low temperature in winter. Only long photoperiod in combination with high temperature stimulated sexual maturation. The capacity of the GnRH binding sites was similar in fish exposed to long (females 1550 pmol, males 1000 pmol) and short (females 1800, males 900) photoperiod in combination with high temperature. In fish exposed to low temperature, binding was nondetectable irrespective of the photoperiod.

Amino Acid Sequence↗
PubMed1992

Oral acitretin in psoriasis: drug and vitamin A concentrations in plasma, skin and adipose tissue.

The purpose of the present study was to determine the concentrations of acitretin and its main metabolite, 13-cis acitretin, in epidermis, subcutis and plasma in twelve psoriatic patients treated with 30 mg acitretin orally daily for 6 months. In addition, endogenous concentrations of vitamin A were monitored. Blood samples and biopsies from normal appearing skin were obtained prior to therapy, after 1 and 6 months of treatment and finally 1 month after cessation of therapy. Using a highly sensitive liquid chromatography method concentrations of synthetic retinoids and endogenous retinoid (retinol, 3,4-didehydroretinol) were analysed in hydrolyzed tissue samples and plasma. Steady-state concentration of acitretin in epidermis (17 +/- 9 ng/g) was reached within 1 month of therapy. There was a significant correlation between the individual plasma trough value and the epidermal concentration of acitretin after 1 month of therapy. The acitretin concentrations in subcutis varied from 15 to 1437 ng/g, but the mean values at 1 and 6 months of therapy were similar (177 and 227 ng/g, respectively). After stopping therapy the acitretin level was below the detection limit in both epidermis and serum within 1 month in 9 out of 12 patients. In contrast, only 3 of the patients were negative for acitretin in subcutis biopsies obtained 1 month after stopping therapy. The occurrence of a presumed tissue contaminator with characteristics similar to 13-cis acitretin prevented quantitation of this metabolite in many subcutis samples. The epidermal, subcutis and serum composition of retinol and 3,4-didehydroretinol remained unchanged during therapy, indicating no or only minimal interaction between acitretin and endogenous vitamin A metabolism.

Acitretin↗
PubMed1991

The effect of 19-hydroxy prostaglandins on the human myometrium in vitro.

Human semen contains high amounts of different prostaglandins of which the quantitatively dominating compounds are 19-hydroxy PGE and 19-hydroxy PGF. The effect of PGE and PGF on the contractility of the human uterus is well known whereas the corresponding 19-hydroxy derivatives have not previously been examined in detail. In the present investigation 19-hydroxy PGE1 was shown to dose-dependently decrease the frequency and the amplitude of the contractions in human myometrial tissue in vitro. The effect of seminal 19-hydroxy prostaglandins may thus be of importance for sperm transport through the female genital tract.

Alprostadil↗
PubMed1991

Evolution of a VH gene family in low vertebrates.

Antibody genes represent one of the most complex receptor gene systems which have evolved in the vertebrate lineage. One of the central questions is how antibody variable region genes diversify the complementarity determining region (CDR) in evolution while they are subject to forces for sequence homogenization operating in multigene families. Information on germ line antibody genes in lower vertebrates is still fragmentary and it would be fruitful to gain insight into this question. We have studied the evolutionary stability of a rainbow trout VH family (RTVH 431) by Southern blot hybridization in various fish species. Comparison of our results with paleontological/zoological evidence suggests that this VH family has been preserved in the genomes of many fish species over a time span of 150 million years. We also show that there exist species-specific residues common to rainbow trout VH genes, which strongly supports the presence of genetic processes for homogenization. These results are compatible with the view that antibody V genes evolve at a fairly constant rate and that the homogenization process (e.g. gene duplication) may be slow enough to allow diversification of CDR by mutation, selection and drift.

Amino Acid Sequence↗
PubMed1991

Synthetic retinoids affect differently the epidermal synthesis of 3,4-didehydroretinol.

For unknown reasons, the epidermal concentrations of retinol and its metabolite 3,4-didehydroretinol become characteristically changed during treatment with certain synthetic retinoids. In the present study we investigated [3H]retinol uptake and conversion to 3,4-[3H]didehydroretinol in cultured human skin exposed to six different retinoids. The tissue accumulation of [3H]retinol increased by 50-130% following addition of 1.3 microM of all-trans-retinoic acid, 13-cis-retinoic acid, or 3,4-didehydroretinoic acid (putative metabolites of retinol), and by 13-55% after addition of acitretin, arotenoid Ro 13-7410, or 4-(N-hydroxyphenyl)retinamide. The formation of 3,4-[3H]didehydroretinol was markedly inhibited (minus 80-90%) by the three putative retinol metabolites, moderately inhibited (minus 60-70%) by the aromatic retinoic acid analogues acitretin and arotinoid, and only slightly inhibited (minus 25%) by 4-(N-hydroxyphenyl)retinamide. Addition of citral and ketoconazole, substances known to interfere with the oxidative metabolism of vitamin A, diminished the formation of 3,4-didehydroretinol by 70 and 95%, respectively, but only marginally affected the retinol values. We conclude that the increase in retinol and marked reduction in 3,4-didehydroretinol concentrations in epidermis especially during treatment with 13-cis-retinoic acid are most likely due to diminished conversion of retinol to 3,4-didehydroretinol, but whether or not this reflects feedback inhibition of retinol metabolism or direct inhibition of a specific enzyme remains to be established. Nonetheless, in vitro analysis of 3,4-didehydroretinol biosynthesis appears to be a sensitive means for screening compounds for their ability to interfere with the cutaneous vitamin A metabolism.

Female↗
PubMed1991

Location of ulcers on the lower limbs in relation to distal systolic blood pressure indices.

The distal systolic blood pressure indices (AI = ankle/arm and TI = toe/arm) of 100 patients with lower limb ulcers at a dermatology outpatient clinic were correlated to ulcer site. The left limb was more often ulcerated than the right. Most ulcers were situated medially, while ulcers on the anterior and posterior sides were infrequent. An AI below 0.9 and TI below 0.6 is usually considered to indicate arterial insufficiency. Forty-four per cent of the patients had an AI less than 0.9 and 66% a TI less than 0.6. The lowest mean indices in all ulcerated limbs were found in patients with ulcers on the feet, followed by those with ulcers in lateral and posterior positions. A significantly lower TI (p = 0.002) was found in the ulcerated limbs when comparing the patients with one ulcerated and one non-ulcerated leg, but no such difference was found for AI. Thus, the ulcerated and the seemingly healthy limb usually had about the same AI. In all patients, TI decreased significantly with age (p = 0.0001). TI was lower in men, than in women, when the effect of age was eliminated (p = 0.0509).

Adult↗
PubMed1990

Bioconversions in aqueous two-phase systems.

Bioconversions involving enzymes and/or microbial cells in aqueous two-phase systems are reviewed. The partitioning of biocatalysts, substrates, and products is discussed in relation to their size. The efficiency of retaining biocatalysts in aqueous two-phase systems is summarized in relation to other methods of recirculating. The influence of phase components on the activity and the stability of enzymatic biocatalysts is exemplified with penicillin acylase and the cellulolytic enzyme system, and the effect of phase components on biocatalytic living cells is exemplified with the production of alpha-amylase with Bacillus sp. Process design costs in bioconversions in aqueous two-phase systems are briefly summarized.

Bacteria↗
PubMed1989

Creativity in old age: a longitudinal study.

A creativity test was administered to a selected sample of 52 subjects all 70 years old and repeated in the same group 13 years later. The stimuli used were diffuse ink-blots coded for three components of creativity: fluency, flexibility and originality. The three components were also summed to form a composite creativity score. Repeated analyses showed no age-related changes in the creativity scores obtained at the two testing times. Furthermore, no gender differences nor age and gender inter-actions were found. The results of this longitudinal study indicate that, contrary to earlier findings from cross-sectional studies, creativity does not seem to decline significantly in old age.

Age Factors↗
PubMed1989

Effects of castration on pituitary gonadotropic cells of the male three-spined stickleback, Gasterosteus aculeatus L., under long photoperiod in winter: indications for a positive feedback.

Male three-spined sticklebacks caught in winter were castrated or sham-operated and subsequently kept under long photoperiod at about 20 degrees for a month. With this treatment the sham-operated fish attained breeding condition. The gonadotropic cells of the sham-operated fish contained significantly more dilated endoplasmic reticulum and fewer granules than those of the castrated fish, indicating a higher secretory activity of the gonadotrops in the sham-operated fish. These findings suggest the existence of a physiological positive feedback within the gonadal-pituitary axis of the male stickleback when stimulated into its breeding condition by long photoperiod.

Animals↗
PubMed1989

Characterization of gonadotropin-releasing hormone binding sites in the pituitary of the three-spined stickleback, Gasterosteus aculeatus.

Binding sites for gonadotropin-releasing hormone (GnRH) in stickleback pituitary homogenates were characterized using an iodinated, superactive analog of salmon GnRH (sGnRH), D-Arg6-Pro9-sGnRH-NEt (sGnRHa). Binding of 125I-sGnRHa reached equilibrium after 60 min incubation at 4 degrees and was a function of tissue concentration. The specificity of 125I-sGnRHa binding was demonstrated by displacement with sGnRHa, sGnRH, and Buserelin [D-Ser(t-Bu)6-Pro9-GnRH-NEt]. Both Scatchard analyses of saturation data and displacement curves revealed a single class of high-affinity binding sites (Ka = 0.71 +/- 0.03 X 10(9) M-1, Bmax = 1087 +/- 165 fmol/mg protein).

Animals↗
PubMed1989

Splanchnic and peripheral release of 3-methylhistidine in relation to its urinary excretion in human infection.

The present investigation was undertaken in order to determine the release of 3-methylhistidine (3MH) from the splanchnic region and from the leg, and the contributions these make to the increase in urinary 3MH excretion in infection. Thirteen febrile patients with infection were investigated. After an overnight fast, hepatic vein, femoral vein, and radial artery catheterizations were performed. Splanchnic and leg blood flows were determined by dye dilution technique. Plasma 3MH was analyzed by a modified HPLC method. The release of 3MH from the leg was 0.064 +/- 0.007 mumol/min (+/- SE) and from the splanchnic region 0.012 +/- 0.013 mumol/min. These releases of 3MH constitute 27% +/- 2% and 8% +/- 6% of the individual urinary excretions, respectively. With increasing degree of catabolism, measured as individual 3MH increase above baseline excretion or as the 3MH to creatinine ratio (3MH:Cr), the relative contribution to urinary excretion from the leg was increased (individual increase, P = 0.08; 3MH:Cr, P less than 0.01). Since this contribution was not decreased in the more catabolic patients, as would have been expected if the increase in urinary 3MH originated elsewhere, it is concluded that skeletal muscle is the source, and these results thus validate the use of urinary 3MH excretion as a marker of myofibrillar protein catabolism in infected patients.

Adult↗
PubMed1989

Exchange of 3-methylhistidine in the splanchnic region in human infection.

This investigation was undertaken to determine the splanchnic exchange of 3-methylhistidine (3MH) in infection. Hepatic vein, femoral vein, and radial artery catheterizations were performed in 12 febrile patients with infections of varying severity. Differences in arteriovenous 3MH, analyzed by high-performance liquid chromatography, were multiplied by the plasma flows, determined by a dye dilution technique. The mean splanchnic efflux was 0.062 +/- 0.180 mumol/min (mean +/- SD) with uptake occurring in five patients. The splanchnic uptake was significantly (p less than 0.001) correlated with the urinary 3MH excretion and the peripheral release from the leg. It is concluded that in human infection, splanchnic 3MH release is low and in patients with high rates of myofibrillar catabolism there may even be an uptake. The urinary 3MH excretion is still a marker of myofibrillar protein breakdown because it correlates well with the release from the leg, regardless of whether the patient has a splanchnic uptake or a release.

Chromatography, High Pressure Liquid↗
PubMed1989

Aromatase activity in the brain of the three-spined stickleback, Gasterosteus aculeatus. III. Effects of castration under different conditions and of replacement with different androgens.

Non-breeding stickleback males were gonadectomized or sham-operated in winter. They were then exposed to a high temperature and either a short photoperiod which did not induce breeding or to a longer, stimulatory, photoperiod. In the latter experiment empty Silastic capsules or capsules filled with the aromatizable androgen, androstenedione or the non-aromatizable androgen, 11-ketoandrostenedione were implanted intraperitoneally in the operated fish. Furthermore, males that were already in breeding condition were gonadectomized or sham-operated in late spring. Brains were freeze-sectioned and punches from the nucleus preopticus-nucleus anterioris periventricularis region were incubated with [19-3H]-androstenedione. After extraction of steroids with CH2CI2, the tritium activity remaining in the water phase gives a measure of aromatization as tritiated water and formic acid are formed when [19-3H]-androstenedione is aromatized to oestrogens. The aromatase activity was higher in sham-operated than in castrated fish in all three experiments. Both androstenedione and 11-ketoandrostenedione abolished the effect of gonadectomy on aromatization.

Androgens↗