Photoemission, autoionization, and x-ray-absorption spectroscopy of ultrathin-film C60 on Au(110).
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Journal Article↗
Biomedical subjects
A Nilsson
Publications and source records attributed to A Nilsson.
FTIR study of lamellar and reversed micellar phases in the mono-oleoylglycerol/water system.
The lamellar liquid crystalline (L alpha) and the reversed micellar (L2) phases of mono-oleoylglycerol (MO) in water were investigated by Fourier transform infrared (FTIR) spectroscopy. From polarized infrared spectra of aligned bilayers of MO/water, order parameters (S) were determined for vibrational modes in the hydrocarbon chain region (symmetric CH2 stretch and olefinic CH=CH stretch) and the aggregate surface region (C=O stretch and asymmetric CO-O-C stretch). The phase transition between L alpha and L2 (10 wt% water) occurs in the temperature range 43-46 degrees C. Already at about 32 degrees C the LD value for the C-OH stretching vibration has decreased to 50% of its value at 25 degrees C. A similar relative decrease in LD is obtained for the C=O stretch and the asymmetric CO-O-C stretch at about 38 degrees C and for the CH=CH stretch at about 43 degrees C. It is concluded that the molecular ordering in the region of the aggregate surface starts to decrease at a lower temperature than for the acyl chain region. Infrared spectra show a significant decrease in the conformational order of the hydrocarbon chains at the L alpha/L2 phase transition.
Chemical Phenomena↗
Vibrationally selective autoionization of physisorbed molecular nitrogen.
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Journal Article↗
Digestion of triacylglycerols containing long-chain polyenoic fatty acids in vitro by colipase-dependent pancreatic lipase and human milk bile salt-stimulated lipase.
To assess the role of human milk bile salt-stimulated lipase (BSSL) in the digestion of polyunsaturated ester bonds of triacylglycerols, hydrolysis of docosahexaenoic acid (22:6(n-3)) ester bonds was compared to that of oleic acid (18:1(n-9)) or arachidonic acid (20:4(n-6)) esters. As model substrates, we used rat chylomicrons obtained after feeding human milk fat globules and radiolabeled fatty acids. Radiolabeled chylomicrons were incubated with colipase-dependent pancreatic lipase, with BSSL, or with both enzymes in combination. Both enzymes hydrolyzed 18:1 more efficiently than 22:6 esters. With colipase-dependent lipase there was a large accumulation of 22:6 in diacylglycerol whereas with BSSL it accumulated mainly in monoacylglycerol. Esters containing 20:4 were hydrolyzed by BSSL as efficiently as 18:1 but this fatty acid also accumulated as diacylglycerol with colipase-dependent lipase. At low bile salt concentrations, as found in duodenal contents of newborns, colipase-dependent lipase was virtually unable to hydrolyze esters of 20:4 and 22:6 whereas BSSL hydrolyzed these esters at appreciable rates. Combining the two enzymes gave the most efficient hydrolysis of all fatty acids tested regardless of bile salt concentrations. BSSL may thus have a physiological role in completing duodenal hydrolysis of milk triacylglycerols containing 22:6- or 20:4-esters to free fatty acids and monoacylglycerol.
Arachidonic Acid↗
Parameters of immunological competence in subjects with high consumption of fish contaminated with persistent organochlorine compounds.
Consumption of fatty fish species, like salmon and herring, from the Baltic Sea is an important source of human exposure to persistent organochlorine compounds, e.g. polychlorinated dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). Many of these compounds show immunotoxic and hepatotoxic effects in animals. We have now studied immunological competence, including lymphocyte subsets, in 23 males with a high consumption of fish from the Baltic Sea and in a control group of 20 males with virtually no fish consumption. The high consumers had lower proportions and numbers of natural killer (NK) cells, identified by the CD 56 marker, in peripheral blood than the non-consumers. Weekly intake of fatty fish correlated negatively with proportions of NK cells (rs = -0.32, P = 0.04). There were also, in a subsample of 11 subjects, significant negative correlations between numbers of NK cells and blood levels of a toxic non-ortho-PCB congener (IUPAC 126; rs = -0.68, P = 0.02) and a mono-ortho congener (IUPAC 118; rs = -0.76, P = 0.01). A similar correlation, in 12 subjects, was seen for p,p'-DDT (rs = -0.76, P = 0.01). The corresponding negative correlation, in 13 subjects, with blood levels of PCDD/Fs was not significant (rs = -0.57, P = 0.07). No significant association was seen between organic mercury in erythrocytes and NK cells. Fish consumption was not associated with levels of any other lymphocyte subset. Neither were there any correlations with plasma immunoglobulins or liver enzyme activities. Our study indicates that accumulation of persistent organochlorine compounds in high consumers of fatty fish may adversely affect NK cell levels.
Adult↗
Hormonal regulation of longitudinal bone growth.
The regulation of postnatal somatic growth is complex. Genetic, nutritional factors and hormones exert regulatory functions. Hormones that have an established role in the regulation include growth hormone (GH), thyroid hormone and sex steroids. GH promotes mainly the growth of the long bones in terms of final height, while the action of the sex steroids and thyroid hormone is less well known. Longitudinal bone growth is the result of chondrocyte proliferation and subsequent endochondral ossification in the epiphyseal growth-plates. The growth-plate is a cartilaginous template that is located between the epiphysis and the metaphysis of the long bones. GH and insulin-like growth factor-I (IGF-I) have different target cells in the epiphyseal growth-plate. GH stimulates the slowly dividing prechondrocytes in the germinative cell layer while IGF-I promotes the clonal expansion in the proliferative cell layer of a GH primed cell. Thyroid hormone blocks the clonal expansion and stimulates chondrocyte maturation. IGF-I mRNA is primarily regulated by GH, and IGF-I is produced in several tissues such as the liver, muscle, fat and epiphyseal growth plates. However, IGF-I mRNA is also increased during compensatory growth of heart and kidneys and by estrogen in the Fallopian tube in the rat. Nutrition, i.e. energy from fat and carbohydrates and proteins, also influences the final height, but the cellular mechanism of action is not known. The aim of this article is to review hormonal action on longitudinal bone growth.
Animals↗
Proteolytic activity in pancreatic pseudocyst fluid.
Pancreatic pseudocyst fluids from 15 patients were biochemically analyzed, especially concerning proteolytic activity and protease inhibitors, and correlated to the clinical course. The pseudocyst fluid was a mixture of pancreatic juice and plasma possessing a high proteolytic activity against high- as well against low-mol-wt proteins. There was practically no functional protease inhibitory capacity left, although immunoreactive inhibitors were present. No distinct biochemical findings differed between fluids from "acute" or from "chronic" pseudocysts. It is concluded, that high proteolytic activity within a pancreatic pseudocyst could well explain symptoms as well as complications caused by the pseudocyst. Biochemical analysis of the pseudocyst fluid cannot, however, be used to differentiate between pseudocysts with a harmless or a complicated course.
Acute Disease↗
Urinary excretion of methylamines in men with varying intake of fish from the Baltic Sea.
Fish contain methylamines, especially trimethylamine N-oxide (TMAO), trimethylamine (TMA), and dimethylamine (DMA). Further, DMA may be formed TMA and TMAO. DMA is a precursor of nitrosodimethylamine (NDMA), which is a potent carcinogen. Levels of DMA, TMA, and TMAO in urine were used as indicators of the dietary exposure and in vivo formation of these amines in 44 men, representing 3 groups with different fish consumption habits. The levels of TMA (median 0.24 mmol/mol creatinine; range 0-2.7) and TMAO (median 38 mmol/mol creatinine; range 8-290) were significantly associated with the weekly intake of fish (r = .47, p = .001, and r = .53, p = .0002, respectively), while no such relation was found for DMA (median 24 mmol/mol creatinine; range 5-46). Further, urinary levels of TMA and TMAO were dependent on recent intake of fish.
Adult↗
Yrast level structure of the neutron deficient N=49 isotones 92Tc, 93Ru, 94Rh, and 95Pd up to high angular momentum.
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Journal Article↗
Gaps in the yrast level structure of the N=50 isotones 93Tc, 94Ru, and 95Rh at high angular momentum.
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Journal Article↗
Pharmacokinetics and retrograde colonic spread of budesonide enemas in patients with distal ulcerative colitis.
METHODS: The retrograde spread of two budesonide enema formulations with different viscosities was investigated. The study design was open, randomized and two-period crossover. Three female and two male patients (age range: 35-45 years) with distal ulcerative colitis or proctitis participated. Both enema formulations contained a dose of 2 mg budesonide/100 mL. An unabsorbable radioactive marker (99mTc-labelled human serum albumin microcolloid) was added to the enema just before administration. All doses were given in the evening with the patients lying in a supine position during the whole investigation. The intestinal spread was followed for 8 h using scintigraphic imaging. Plasma samples for budesonide assay were taken during the 12 h after administration of the low viscosity enema. RESULTS: Budesonide plasma levels were measurable for up to 4-6 h. Cmax was 2.5 nmol/L (range: 0.9-4.5 nmol/L) and was attained in 1.5 h (range 1-3 h). The patients had no difficulty in retaining the enemas. There was a statistically significant difference in spread between the low and high viscosity enema. The low viscosity enema spread over an area situated between the rectum and the splenic flexure. The spread occurred mainly in the first 15 min after administration. In contrast, the high viscosity enema, in most cases, spread only over a minor part of this area and the rate and extent of spreading was also more variable with this formulation. CONCLUSION: The spread of a low viscosity enema appears to be well suited for the treatment of proctitis and distal colitis.
Administration, Topical↗
The EMLA patch--a new type of local anaesthetic application for dermal analgesia in children.
The skin application of EMLA cream under a Tegaderm dressing was compared in children with a new combined dressing/local anaesthetic patch--the EMLA patch. The analgesic effect during venepuncture was assessed using a visual analogue scale (patients) and a verbal rating scale (investigator). Skin adhesiveness and incidence of local skin reactions with the two types of application were also studied. The study was designed as an open randomised trial with two parallel groups. Sixty children, aged between 5 and 15 years were evaluated. After a minimum application time of 60 min an intravenous cannula was inserted. There was no difference in analgesia as assessed by the patients or the investigators. Mild discomfort at removal of the occlusive dressing/patch was observed in a few patients, but there was no difference in the adhesiveness of the Tegaderm dressing and the EMLA patch. Only mild local skin reactions (with paleness in the anaesthetised skin area) were observed in both groups. It was concluded that both the EMLA patch and the Tegaderm/EMLA cream dressing provide effective dermal analgesia for venepuncture with a 0.8 mm (outer diameter) cannula. The two types of application were indistinguishable but the ease of application of the patch is a distinct advantage.
Adolescent↗
Mental status after transurethral resection of the prostate.
We examined cognitive functions by means of a standardized mini-mental status (MMS) test before and 2 and 24 h after surgery in 100 patients undergoing transurethral resection of the prostate (TURP). There was a strong correlation between the results of this test on all three occasions, but a transient deterioration in the MMS score occurred 2 h after TURP in two thirds of the patients. Fluid absorption was the factor most strongly associated with the change in MMS status during TURP, while the preoperative health status and the choice of anesthesia (general or spinal) had no influence.
Aged↗
Chylomicron-induced prothrombin activation and platelet aggregation.
The effects on platelet aggregation of native rat chyle chylomicrons, chylomicron remnants, and chylomicrons that had been preincubated with rat or human EDTA-plasma, serum, whole blood, or pure human prothrombin were examined. The native chyle chylomicrons did not induce platelet aggregation but decreased ADP- and thrombin-induced platelet aggregation and [14C]serotonin release. Chylomicron remnants also failed to induce platelet aggregation, but they potentiated the aggregation and the [14C]serotonin release induced by ADP and thrombin. Aggregation, after a lag phase of 15 to 20 minutes, was seen when platelets were incubated with chylomicrons that had been preincubated with plasma and then isolated as the top layer after a single centrifugation at d = 1.006. This aggregation was inhibited in a dose-dependent manner by an antiserum against prothrombin that also inhibited thrombin-induced platelet aggregation. After washing by centrifugation the plasma-preincubated chylomicrons did not induce platelet aggregation, but this effect could be restored by adding a small amount of prothrombin, which did not cause aggregation when added alone or together with native chyle chylomicrons. Addition of 2% (vol/vol) plasma, however, induced aggregation when added together with either native chyle chylomicrons or washed preincubated chylomicrons, but not when added alone. Binding of 125I-labeled prothrombin to native chyle chylomicrons was demonstrated by gradient ultracentrifugation. During incubation of washed plasma-preincubated chylomicrons with 125I-prothrombin and platelets, a significant conversion of 125I-prothrombin to 125I-prethrombin and 125I-thrombin occurred, as demonstrated by autoradiography after separation on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The interaction between chylomicrons and prothrombin, and possibly other coagulation proteins, thus enhances prothrombin activation in the presence of platelets.
Animals↗
Absorption and incorporation into tissue lipids of 3H-arachidonic- and 14C-linoleic acid: effects of ethanol in jejunal tissue cultures and in vivo.
The effects of ethanol in the rat on the absorption and incorporation of 3H-arachidonic (20: 4, n-6) and 14C-linoleic acid (18:2, n-6) into tissue lipids was examined in jejunal tissue cultures in vivo. The pattern of incorporation earlier seen in the small intestine in vivo, ie. a preferential incorporation of 3H-20: 4 in comparison to 14C-18: 2 into phospholipids (PL), particularly phosphatidylethanolamine (PE) and phosphatidylinositol (PI) was seen in the jejunal tissue cultures. 10 mM ethanol slightly decreased the incorporation of 3H-20: 4 into PE and PI, but did not change the partitioning of labelled fatty acids into phospholipids and triacylglycerols (TG). Ethanol (100 mM) decreased the incorporation of both 3H and 14C into both PL and TG and caused a moderate increase in the TG/PL radioactivity ratio. Rats were also infused intraduodenally with either 10% ethanol or saline and given 3H-20: 4 and 14C-18: 2 in Intralipid. Radioactivity of tissue lipids were analysed after 1, 2 and 3 h. Ethanol did not significantly influence the absorption or the retention in small intestine, liver or heart of 3H or 14C, or the time course for the 3H- and 14C lipid radioactivity in serum. The distribution of 3H and 14C between total nonpolar lipids and individual PLs was also similar in the two groups, 3H-20: 4 thus exhibiting the same preferential incorporation into PLs, compared to 14C-18: 2, in both groups. Significant amounts of 3H and 14C appeared in phosphatidylethanol (PEth) of the small intestine, heart and liver, when the tissues from the ethanol-infused animals were stored frozen before extraction. When the tissues were extracted immediately after the experiment, the proportions of 3H and 14C migrating as PEth did not exceed 0.5%. Although sufficient amounts of ethanol and the phospholipase D activity necessary for PEth formation were thus present in the tissues examined, little PEth formation thus occurred during the ethanol infusion. In the ethanol treated group about 1% of the 3H and 14C radioactivity of the small intestine was in ethyl ester. Intraduodenal infusion of 10% ethanol in vivo thus has little acute effects on the metabolism of absorbed 18: 2 and 20: 4 in the intestinal mucosal cells. Formation of some ethyl ester occurs, however.
Animals↗
Hydrolysis of phosphatidylethanolamine by human pancreatic phospholipase A2. Effect of bile salts.
The 2-ester bond of 14C-2-arachidonyl phosphatidylethanolamine (PE) was hydrolyzed faster than that of 3H-2-arachidonyl phosphatidylcholine (PC) by human pancreatic phospholipase A2 (PLA2) with mixed PE-PC (1:9 w/w) liposomes of pure sonicated PE or PC as substrate. The PC portion of the mixed PE-PC liposomes was more readily attacked by PLA2 than the PC of pure PC liposomes. At different bile salt concentrations (sodium taurocholate (NaTC), 0-3 mM, and sodium taurodeoxycholate (NaTDC), 0-4 mM) the rates of hydrolysis varied with similar patterns for both phospholipids of the mixed liposomes. The rate of hydrolysis was optimal at a bile salt concentration of 0.75-1.5 mM NaTC and 1.0-2.0 mM NaTDC and decreased at higher concentrations. The pure PE substrate was efficiently hydrolyzed also without bile salts. This may have implications for the absorption of polyunsaturated phospholipid fatty acids in patients with bile salt deficiency. Separation of phospholipid classes from human bile by high-performance liquid chromatography and analysis of fatty acid composition indicated that PE contained 5.3% of the phospholipid arachidonic acid and 9.8% of the docosahexaenoic acid mass, but only 1.7% of the total phospholipid mass. Bile and dietary PE should not be overlooked as sources of arachidonic and docosahexaenoic acid for the small intestine.
Bile↗
The expression of glutathione transferase mu in patients with inflammatory bowel disease.
BACKGROUND: Glutathione transferases (GST) are a group of multifunctional enzymes important in the detoxification of many electrophiles and, in addition, fatty acid hydroperoxides, thus limiting tissue damage from oxidative free radical attack. Of the four classes of GST (alpha, mu, pi, and theta), a class mu isoenzyme, GST mu, is dominantly inherited and is expressed in approximately half of the population. GST mu expression was examined in patients with inflammatory bowel disease and correlated to clinical course, extension, and age of onset of the diseases. METHODS: GST mu can be measured as GST activity against trans-stilbene oxide. This GST activity was measured in whole blood in 179 patients with ulcerative colitis, 109 patients with Crohn's disease, and 449 age-matched controls. RESULTS: Frequencies of GST mu expression were as follows: controls (n = 449, 51.2%), mild ulcerative colitis (n = 76, 47.3%), moderate ulcerative colitis (n = 43, 46.5%), and severe ulcerative colitis (characterized by colectomy) (n = 60, 36.7%). This trend was, however, not significant (p = 0.094). Patients with onset of the colitis before the age of 30 years (n = 91) had a lower frequency of GST mu expression (35.2%) than patients with a later onset (n = 88, 52.3%) (p < 0.05). This difference was more pronounced among the colectomized patients (19.4% versus 55.2%) (p < 0.01). In Crohn's disease, patients with colitis had a lower frequency of GST mu expression (n = 29, 31.0%) than controls; however, this was not statistically significant (p = 0.055). No difference was found with regard to age of onset. CONCLUSION: We conclude that in patients with ulcerative colitis, lack of GST mu is related to early age of onset and a more severe clinical course leading to colectomy.
Adult↗
Metabolism of chylomicron phosphatidylinositol in the rat: fate in vivo and hydrolysis with lipoprotein lipase and hepatic lipase in vitro.
Phosphatidylinositol (PI), mainly stearoyl-arachidonyl PI, occurs as a minor phospholipid constituent in both chyle and plasma lipoproteins. The kinetics and the pathway by which plasma and chyle PI is metabolized have not been investigated. The role of lipoprotein PI in the supply of arachidonic acid (20:4) and inositol lipid components to different tissues is thus unknown. In this study we examined the fate of chyle PI in vivo and its hydrolysis by lipoprotein lipase (LPL), hepatic lipase (HL), and postheparin plasma in vitro. Chyle and chylomicrons were labeled in the PI portion by feeding [3H]myo-inositol and in the phosphatidylcholine (PC) portion by feeding [14C]choline in a linoleate-rich fat meal (Intralipid) to mesenteric duct-cannulated rats. After intravenous injection of doubly labeled chyle into normal rats, [3H]PI disappeared from plasma at a slower rate than [14C]PC; after 60 min 41.6 +/- 2.7% 3H and 24.3 +/- 1.8% 14C (means +/- SEM, n = 4, P < 0.01) remained in plasma lipids. About 15% of both isotopes were in liver lipids after 60 min. Previous injection of a blocking antiserum against rat HL did not significantly influence the serum and liver radioactivity after 60 min. Radioactive PI was rapidly transferred to high density lipoproteins (HDL) during the metabolism of chylomicrons. Analysis of 3H and 14C in different molecular species of PI and PC in chyle and in serum indicated that there was no significant difference in disappearance rates between various species, stearoyl-arachidonyl PI thus disappearing at the same rate as total [3H]PI. Both lipoprotein lipase (LPL) and HL catalyzed formation of lyso-PI in vitro, the rate being increased by the addition of serum. About 60% of the lyso-PI formation catalyzed by postheparin plasma in 60 min could be blocked by antiserum to HL, which almost completely blocked the hydrolysis occurring after the first 10 min. The study thus shows that both LPL and HL hydrolyze chylomicron PI in vitro. LPL and HL may, however, be of limited importance for the clearance of chyle PI in vivo, most of the chylomicron PI being transferred to HDL, and thereafter eliminated from plasma at a slow rate mainly by other mechanisms.
Animals↗