Showing papers by "Lund University published in 1992"
TL;DR: A model to predict global patterns in vegetation physiognomy was developed from physiological considera- tions influencing the distributions of different functional types of plant in a given environment, and selected the potentially dominant types from among them as discussed by the authors.
Abstract: A model to predict global patterns in vegetation physiognomy was developed from physiological considera- tions influencing the distributions of different functional types of plant. Primary driving variables are mean coldest- month temperature, annual accumulated temeprature over 5"C, and a drought index incorporating the seasonality of precipitation and the available water capacity of the soil. The model predicts which plant types can occur in a given environment, and selects the potentially dominant types from among them. Biomes arise as combinations of domi- nant types. Global environmental data were supplied as monthly means of temperature, precipitation and sunshine (interpolated to a global 0.5" grid, with a lapse-rate correc-
2,040 citations
TL;DR: Differences in the pump/leak relationship for calcium explain why calcium and glutamate antagonists may lack effect on the cardiac arrest type of ischemia, while decreasing infarct size in focal ischemIA.
Abstract: ✓ The mechanisms that give rise to ischemic brain damage have not been definitively determined, but considerable evidence exists that three major factors are involved: increases in the intercellular cytosolic calcium concentration (Ca++i), acidosis, and production of free radicals. A nonphysiological rise in Ca++i due to a disturbed pump/leak relationship for calcium is believed to cause cell damage by overactivation of lipases and proteases and possibly also of endonucleases, and by alterations of protein phosphorylation, which secondarily affects protein synthesis and genome expression. The severity of this disturbance depends on the density of ischemia. In complete or near-complete ischemia of the cardiac arrest type, pump activity has ceased and the calcium leak is enhanced by the massive release of excitatory amino acids. As a result, multiple calcium channels are opened. This is probably the scenario in the focus of an ischemic lesion due to middle cerebral artery occlusion. Such ischemic tissues ca...
1,136 citations
1,012 citations
TL;DR: It appears to be possible to prevent haemophilic arthropathy by giving effective continuous prophylaxis from an early age, and preventing the VIII:C or IX:C concentration from falling below 1% of normal.
Abstract: In Sweden, prophylactic treatment of boys with severe haemophilia has been practised since 1958 in an attempt to convert the disease from a severe to a milder form. The present study population consisted of 60 severe haemophiliacs (52 A, 8 B), aged 3-32 years. Treatment is started when the boys are 1-2 years of age, the regimens used being 24-40 IU F VIII kg-1 three times weekly in haemophilia-A cases (i.e. greater than 2000 IU kg-1 annually) and 25-40 IU F IX kg-1 twice weekly in haemophilia-B cases. The orthopaedic and radiological joint scores (maximum scores of 90 and 78, respectively) are evaluated as recommended by the World Federation of Haemophilia. Of those subjects aged 3-17 years, 29 out of 35 individuals had joint scores of zero. The oldest group had only minor joint defects. The VIII:C and IX:C concentrations had usually not fallen below 1% of normal. All 60 patients are able to lead normal lives. In conclusion, it appears to be possible to prevent haemophilic arthropathy by giving effective continuous prophylaxis from an early age, and preventing the VIII:C or IX:C concentration from falling below 1% of normal.
928 citations
TL;DR: In a prospective study all positive phlebographies within the well‐defined population of the city of MalmÖ, Sweden, during 1987 were studied in order to determine the incidence of deep venous thrombosis (DVT), and risk factors were found to be in accordance with earlier studies.
Abstract: In a prospective study all positive phlebographies within the well-defined population of the city of Malmo, Sweden, during 1987 were studied in order to determine the incidence of deep venous thrombosis (DVT). Epidemiological data were analysed for the detection of patient groups at increased risk of DVT. The incidence was found to be equal for both sexes, i.e. 1.6 per 1000 inhabitants a year. Risk factors were found to be in accordance with earlier studies. The median age for men was 66 years, compared to 72 years for women. At diagnosis of DVT, 19% of subjects had a known malignancy and within 1 year 5% (19 cases) developed a new malignancy. Of the men, 29% had postoperative or post-traumatic (fracture) DVT, compared to 46% of the women. Fewer patients with DVT than expected (39%) belonged to blood group 0 (31%) (P less than 0.005). Pulmonary embolism (PE) was clinically suspected in only 5% of cases, and diagnosis was verified scintigraphically in 2% of cases. None of these died of PE, but of 6 patients who were found to have PE at autopsy, four died about 4 weeks after the DVT was diagnosed.
803 citations
TL;DR: In this article, the authors show the results of spectral analyses of treering data from northern Sweden and show that only a few peaks in the spectra are consistently significant when the data are analyzed over a number of sub-periods.
Abstract: Quantitative estimates of 1480 years of summer temperatures in northern Fennoscandia have previously been derived from continuous treering records from northern Sweden. Here we show the results of spectral analyses of these data. Only a few peaks in the spectra are consistently significant when the data are analyzed over a number of sub-periods. Relatively timestable peaks are apparent at periods of 2.1, 2.5, 3.1, 3.6, 4.8, ∼ 32–33 and for a range between ∼ 55–100 years. These results offer no strong evidence for solar-related forcing of summer temperatures in these regions. Our previously published reconstruction was limited in its ability to represent long-timescale temperature change because of the method used to standardize the original tree-ring data. Here we employ an alternative standardization technique which enables us to capture temperature change on longer timescales. Considerable variance is now reconstructed on timescales of several centuries. In comparison with modern normals (1951–70) generally extended periods when cool conditions prevailed, prior to the start of the instrumental record, include 500–700, 790–870, 1110–1150, 1190–1360, 1570–1750 (A.D.) with the most significant cold troughs centred on about 660, 800, 1140, 1580–1620 and 1640. Predominantly warm conditions occurred in 720–790, 870–1110 and 1360–1570 with peaks of warmth around 750, 930, 990, 1060, 1090, 1160, 1410, 1430, 1760 and 1820.
675 citations
TL;DR: It is concluded that, in contrast to inhaled terbutaline, inhaled budesonide improved lung function and bronchial hyperreactivity in adult subjects with asthma treated for 3 months and that this corticosteroid was more effective in ameliorating abnormalities of theBronchial epithelium and decreasing inflammation in the airways.
Abstract: We compared the effect of an inhaled corticosteroid, budesonide, and an inhaled beta 2-agonist, terbutaline, on clinical symptoms, lung function, and airway inflammation in 14 adult patients with newly diagnosed asthma. The study was conducted as a randomized, double-blind, parallel-group trial. Seven patients inhaled 600 micrograms, twice daily, of budesonide, the other seven patients inhaled 375 micrograms, twice daily, of terbutaline via identical metered-dose inhalers with a spacer. Bronchial biopsy specimens, obtained before randomization and after 3 months of treatment, were analyzed by electron microscopy. Both groups improved clinically budesonide was more effective than terbutaline in improving morning and evening peak expiratory flow rates, as well as bronchial responsiveness to inhaled histamine. Treatment with budesonide was accompanied by increased numbers of ciliated airway cells and intraepithelial nerves and fewer inflammatory cells, including eosinophils, especially in the epithelium, these changes were not observed in specimens from terbutaline-treated patients. We conclude that, in contrast to inhaled terbutaline, inhaled budesonide improved lung function and bronchial hyperreactivity in adult subjects with asthma treated for 3 months and that this corticosteroid was more effective in ameliorating abnormalities of the bronchial epithelium and decreasing inflammation in the airways.
590 citations
TL;DR: Estimation of prey vulnerability to predation by pike, a gape-limited predator, revealed that this increase in body depth resulted in crucian carp reaching a size that provided refuge from predation, however, this change in morphology incurs a cost through an increase in drag when the carp are swimming.
Abstract: In a field experiment where the presence or absence of piscivorous pike (Esox lucius) in ponds was manipulated, the morphology of crucian carp (Carassius carassius) diverged, such that individuals became deeper bodied in pond sections with pike. A laboratory experiment confirmed that the presence of this predator induced a change in body morphology in the carp. Estimation of prey vulnerability to predation by pike, a gape-limited predator, revealed that this increase in body depth resulted in crucian carp reaching a size that provided refuge from predation. However, this change in morphology incurs a cost through an increase in drag when the carp are swimming. Because crucian carp are limited by resources in the absence of piscivores and by the substantial cost of the defensive morph in their presence, phenotypic plasticity should be the optimal strategy for this species.
552 citations
TL;DR: In situ hybridization was used to study expression of mRNAs for members of the nerve growth factor (NGF) family in the rat brain after 2 and 10 min of forebrain ischemia and 1 and 30 min of insulin-induced hypoglycemic coma to influence functional outcome and neuronal necrosis following ischemic and hypogly diabetic insults.
Abstract: In situ hybridization was used to study expression of mRNAs for members of the nerve growth factor (NGF) family in the rat brain after 2 and 10 min of forebrain ischemia and 1 and 30 min of insulin-induced hypoglycemic coma. Two hours after the ischemic insults, the level of brain-derived neurotrophic factor (BDNF) mRNA was markedly increased in the granule cells of the dentate gyrus, and at 24 h it was still significantly elevated. NGF mRNA showed a pronounced increase 4 h after 2 min of ischemia but had returned to a control level at 24 h. Both 2 and 10 min of ischemia caused a clear reduction of the level of mRNA for neurotrophin 3 (NT-3) in the dentate granule cells and in regions CA2 and medial CA1 of the hippocampus 2 and 4 h after the insults. The increase of BDNF mRNA could be partially blocked by the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist NBQX but was not influenced by the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801. Both NBQX and MK-801 attenuated the decrease of NT-3 mRNA after ischemia. One and 30 min of hypoglycemic coma also induced marked increases in BDNF and NGF mRNA in dentate granule cells with maximal levels at 2 h. If the changes of mRNA expression lead to alterations in the relative availability of neurotrophic factors, this could influence functional outcome and neuronal necrosis following ischemic and hypoglycemic insults.
522 citations
TL;DR: In this paper, the phase behavior of aqueous polymer/surfactant mixtures is reviewed and compared with the phase behaviour of analogous polymeric or surfactant mixture.
521 citations
TL;DR: An Mr = 524,000 oligomeric protein was isolated from bovine cartilage and designated COMP (Cartilage Oligomeric Matrix Protein), which is markedly anionic and shows a preferential localization to the territorial matrix surrounding the chondrocytes.
TL;DR: Bilateral implantation of fetal mesencephalic tissue can induce substantial long-term functional improvement in patients with parkinsonism and severe dopamine depletion and is accompanied by increased uptake of fluorodopa by the striatum.
Abstract: Background. Intracerebral transplantation of fetal dopaminergic neurons is a promising new approach for the treatment of Parkinson's disease. Patients with parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) have a relatively stable lesion limited to the nigrostriatal system, rendering them ideal candidates for transplantation. Improvement of motor function after neural grafting has previously been observed in nonhuman primates with MPTP-induced parkinsonism. Methods. We grafted human fetal tissue from the ventral mesencephalon (obtained six to eight weeks after conception) bilaterally to the caudate and putamen in two immunosuppressed patients with severe MPTP-induced parkinsonism, using a stereotaxic technique. The patients were assessed regularly with clinical rating scales, timed tests of motor performance, and [18F]fluorodopa positron-emission tomography during the 18 months before the operation and the 22 to 24 months after the operation. Results. Both patients had s...
TL;DR: A reaction scheme where electrophilic activation of carbon dioxide plays an important role in the hydration reaction is presented and the protonized oxygen of the bicarbonate is forced upon the zinc ion, thereby facilitating cleavage of the carbon-oxygen bond.
TL;DR: A pairwise comparison of the nucleic acid sequence of 168 bases from 152 wild-type or unique cell culture-adapted strains of hepatitis A virus (HAV) revealed that HAV strains can be differentiated genetically into seven unique genotypes (I to VII), indicating that patterns of endemic transmission can be distinguished from situations in which infections are imported due to travel.
Abstract: A pairwise comparison of the nucleic acid sequence of 168 bases from 152 wild-type or unique cell culture-adapted strains of hepatitis A virus (HAV) revealed that HAV strains can be differentiated genetically into seven unique genotypes (I to VII). In general, the nucleotide sequence of viruses in different genotypes differs at 15 to 25% of positions within this segment of the genome. Viruses from four of the genotypes (I, II, III and VII) were recovered from cases of hepatitis A in humans, whereas viruses from the other three genotypes (IV, V and VI) were isolated only from simian species developing a hepatitis A-like illness during captivity. Among non-epidemiologically related human HAV strains, 81 were characterized as genotype I, and 19 as genotype III. Within each of these major genotypes, there were two distinct groups (subgenotypes), which differed in sequence at approximately 7.5% of base positions. Each genotype and subgenotype has a characteristic amino acid sequence in this region of the polyprotein, with the most divergent genotypes differing at 10 of 56 residues. Strains recovered from some geographical regions belonged to a common (endemic) genotype, whereas strains from other regions belonged to several, probably imported, genotypes. Thus, HAV strains recovered in North America were for the most part closely related at the nucleotide sequence level, whereas in other regions, such as Japan and Western Europe, HAV strains were derived from multiple genotypes or sub-genotypes. These data indicate that patterns of endemic transmission can be differentiated from situations in which infections are imported due to travel.
TL;DR: A time window for salvage of penumbral tissues by reperfusion in a model of transient focal ischemia that gives infarction of both the caudoputamen and the neocortex is demonstrated.
Abstract: The rat is now extensively used for studies on focal cerebral ischemia, and several novel pharmacological principles have been worked out in rat models of middle cerebral artery occlusion. The objective of the present study was to assess how ischemic tissue can be salvaged by reperfusion in a model of transient focal ischemia that gives infarction of both the caudoputamen and the neocortex.The middle cerebral artery of anesthetized rats was occluded for 15, 30, 60, 90, 120, or 180 minutes by an intraluminal filament, and recirculation was instituted for 7 days to allow assessment of the density and localization of ischemic brain damage using histopathologic techniques. Local cerebral blood flow was measured in separate animals to verify that removal of the filament was followed by adequate recirculation.Following 15 minutes of middle cerebral artery occlusion seven of eight rats showed selective neuronal necrosis in the caudoputamen, while the neocortex was normal. After 30 minutes of occlusion, seven of ...
TL;DR: These field studies on Swedish adders provide the first empirical evidence that multiple copulations, with different partners each time, increase offspring viability.
Abstract: MALES of most animal species will enhance their reproductive success if they mate often and with many different partners, whereas promiscuous mating is unlikely to increase a female's reproductive success. Why then is multiple copulation by females so common1–6? Many theoreticians have suggested that multiple copulations might enhance the viability of a female's offspring, either because of inadequate quantities of sperm from the first mating1,7, additional nutrients derived from the seminal fluid7,8 or some genetic advantage9–14. Our field studies on Swedish adders provide the first empirical evidence that multiple copulations, with different partners each time, increase offspring viability. This advantage apparently results from more intense sperm competition in the female's reproductive tract, resulting in a higher proportion of her ova being fertilized by genetically superior males.
TL;DR: Differentiation and consolidation theory of decision making as mentioned in this paper models human decision making as an active process in which one alternative is gradually differentiated from other available alternatives, and predicts consolidation processes which work in favor of the chosen alternative.
TL;DR: In this article, the authors argue that cultural reality is always produced in specific sociohistorical contexts and that it is necessary to account for the processes that generate those contexts in order to explain the nature of both the practice of identity and the production of historical schemes.
Abstract: deterioration of the conditions that empowered a dominant modernist identity. The latter entails the liberation of formerly encompassed or superseded identities. I shall be arguing that the dehegemonization of the Western-dominated world is simultaneously its dehomogenization. In this article I present two kinds of argument. The first concerns the general relations between identity and the politics of historical construction. The second concerns the current situation of contested representations of other peoples' realities. The overriding argument is that cultural realities are always produced in specific sociohistorical contexts and that it is necessary to account for the processes that generate those contexts in order to account for the nature of both the practice of identity and the production of historical schemes. This includes the identifications "invented" by anthropologists as well as those of the subjects that we engage "out there." I argue, further, that the processes that generate the contexts in which identity is practiced constitute a global arena of potential identity formation. This arena is informed by the interaction between locally specific practices of selfhood and the dynamics of global positioning.
TL;DR: An enzyme-linked immunosorbent assay is developed for the detection of this protein in synovial fluid and serum in patients with rheumatoid arthritis, reactive arthritis, juvenile chronic arthritis, osteoarthritis and in sera of control subjects and the protein was detectable in all fluids and the synovials levels were always higher than in serum in paired samples.
Abstract: Cartilage oligomeric matrix protein (COMP) is a tissue specific non-collagenous matrix protein. We have developed an enzyme-linked immunosorbent assay for the detection of this protein in synovial fluid and serum. The protein has been quantified in these fluids in patients with rheumatoid arthritis (RA), reactive arthritis, juvenile chronic arthritis, osteoarthritis and in sera of control subjects. The protein was detectable in all fluids and the synovial fluid levels were always higher than in serum in paired samples. The highest knee joint synovial fluid levels were found in reactive arthritis patients and the lowest in RA patients with advanced destruction of the knee joint. However, the relative synovial fluid content of COMP was higher in these RA patients than in patients with advanced osteoarthritis. In patients with long-standing reactive synovitis the concentrations decreased. This decrease, however, was less marked than for proteoglycan concentrations. The serum concentrations were low in patients with juvenile chronic arthritis and in patients with RA with advanced cartilage destruction of the studied knee joint. In the other groups serum levels did not differ between groups or from controls.
TL;DR: The results indicate that patients with Parkinson's disease can show significant and sustained improvement of motor function after intrastriatal implantation of fetal dopamine‐rich mesencephalic tissue.
Abstract: Ventral mesencephalic tissue from aborted human fetuses (age, 6-7 weeks' postconception) was implanted unilaterally into the putamen using stereotaxic surgery in 2 immunosuppressed patients (Patients 3 and 4 in our series) with advanced idiopathic Parkinson's disease. Tissue from 4 fetuses was grafted to each patient. Compared with our previous 2 patients, the following changes in the grafting procedure were introduced: the implantation instrument was thinner, more tissue was placed in the operated structure, and the time between abortion and grafting was shorter. There were no postoperative complications. Both patients showed a gradual and significant amelioration of parkinsonian symptoms (most marked in Patient 3) starting at 6 and 12 weeks after grafting, respectively, reaching maximum stability at approximately 4 to 5 months; patients remained relatively stable thereafter during the 1-year follow-up period. Clinical improvement was observed as a reduction of the time spent in the "off" phase and the number of daily "off" periods; a lessening of bradykinesia and rigidity during the "off" phase, mainly but not solely on the side contralateral to the graft; and a prolongation and change in the pattern of the effect of a single dose of L-dopa. Neurophysiological measurements revealed a more rapid performance of simple and complex arm and hand movements bilaterally, but primarily contralateral to the graft. The results indicate that patients with Parkinson's disease can show significant and sustained improvement of motor function after intrastriatal implantation of fetal dopamine-rich mesencephalic tissue. The accompanying paper by Sawle and colleagues describes the results of repeated positron emission tomography scans in these patients.
Journal Article•
TL;DR: It is concluded that the presently described in-vitro procedure offers a good potential to predict the metabolic behaviour of starchy foods.
Abstract: A new method for measuring the rate of in-vitro starch digestion in products with a structure 'as eaten' is introduced. An equivalent amount of potentially available starch from each product was chewed by subjects, expectorated into a beaker and incubated with pepsin. The incubate was thereafter transferred to a dialysis tubing and incubated with pancreatic alpha-amylase for 3 h. Samples were removed from the dialysate at time intervals and the degree of hydrolysis was calculated as the proportion of the potentially available starch degraded to maltose. A hydrolysis index (HI) was calculated as the area under the hydrolysis curve with the product as a percentage of the corresponding area with white wheat bread. The method was applied to 21 cereal and legume products, chosen to cover as wide a range as possible with respect to metabolic response, and to include several of the proposed mechanisms to differences in metabolic behaviour of starch. The accuracy of the in-vitro method was evaluated versus the metabolic responses obtained with the same products in healthy subjects. A significant correlation between HI and glycaemic index (GI) was obtained in cereal as well as in legume products. A significant correlation was also obtained between HI and insulin index (II) with pooled data from all products. However, in the case of II no correlation was obtained with the legume products only. It is concluded that the presently described in-vitro procedure offers a good potential to predict the metabolic behaviour of starchy foods.
TL;DR: Fasting but not post‐load values were lower in postmenopausal women than in men of similar age, and lower among the women as a whole than among the men, and fasting total plasma homocysteine values were significantly and negatively correlated to serum vitamin B12 and blood folate concentrations.
Abstract: Homocysteine is a probably atherogenic amino acid, the fasting and post-methionine load serum concentrations of which have been reported to be much lower in premenopausal women than in men and postmenopausal women. This difference has been proposed to explain the reduced proneness of premenopausal women to vascular disease. We measured both free and total plasma homocysteine concentrations both fasting and post-methionine load, in 169 healthy subjects. Twelve subjects (7%) had distinctly abnormal plasma homocysteine values. Among the remaining 157 subjects, neither fasting nor post-load values of free or total homocysteine were lower in premenopausal women (n = 46) than in men of similar age (n = 41) or postmenopausal women (n = 37). Fasting but not post-load values were lower in postmenopausal women than in men of similar age (n = 33), and lower among the women as a whole (n = 83) than among the men (n = 74). In men, fasting values increased with age, and paralleled age-related decreases in the concentrations of homocysteine metabolism cofactors (serum vitamin B12, blood folate, and plasma pyridoxal 5-phosphate). Both in men and in women, fasting total plasma homocysteine values were significantly and negatively correlated to serum vitamin B12 and blood folate concentrations. Whether the small differences in plasma homocysteine values between the present men and women may be a contributory factor vis-a-vis their different proneness to vascular disease has yet to be settled.
TL;DR: Comparison of the amino acid sequences in the type 2 and type 3 repeat domains of COMP and the thrombospondins shows that COMP is the product of a unique gene and not the result of an alternatively spliced throm bospondin gene.
TL;DR: Flow distribution in a rat model of reversible middle cerebral artery (MCA) occlusion is defined to allow delineation of the metabolic aberrations responsible for the subsequent infarction to help define large parts of the neocortex as perifocal areas which lend themselves to studies of metabolic events leading to infarctions.
Abstract: It has become increasingly clear that a stroke lesion usually consists of a densely ischemic focus and of perifocal areas with better upheld flow rates. At least in rats and cats, some of these perifocal ("penumbral") areas subsequently become recruited in the infarction process. The mechanisms may involve an aberrant cellular calcium metabolism and enhanced production of free radicals. In general, though, the metabolic perturbation in the penumbra requires better characterization. The objective of this article was to define flow distribution in a rat model of reversible middle cerebral artery (MCA) occlusion, so as to allow delineation of the metabolic aberrations responsible for the subsequent infarction. We modified the intraluminal filament occlusion model recently developed by Koizumi et al. (1986), and described in more detail by Nagasawa and Kogure (1989), adopting it for use in both spontaneously breathing and artificially ventilated rats. Successful occlusion of the MCA (achieved in about 9/10 rats) was judged by unilateral EEG depression in ventilated rats, and neurological deficits, such as circling, in spontaneously breathing ones. CBF in the ipsilateral hemisphere was reduced to nearly constant values after 20, 60, and 120 min of occlusion, flow rates in the focus being about 10% and in the perifocal ipsilateral areas about 15-20% of control (contralateral side). When the filament was left in place (permanent occlusion) 2,3,5-triphenyl tetrazolium chloride (TTC) staining and histopathology after 24 h showed a massive infarct on the occluded side, extending from caudoputamen and overlaying cortex to the occipital striate cortex. Animals recirculated after 60 min of MCA occlusion, and allowed to survive 7 days for histopathology, showed infarction of the caudoputamen (lateral part or whole nucleus) in 5/6 animals and selective neuronal necrosis in one animal. The neocortex showed either infarcts, selective neuronal necrosis, or no damage. There was some overlap between neocortical areas which were infarcted and those which were salvaged by reperfusion. In general, though, both the CBF data and the recovery studies with a histopathological endpoint define large parts of the neocortex as perifocal (penumbral) areas which lend themselves to studies of metabolic events leading to infarction.
TL;DR: It is demonstrated that AMPA but not NMDA receptor antagonists decrease neuronal damage following transient severe cerebral ischemia in the rat and that the protection by NBQX may be dependent on the severity of the ischemic insult.
Abstract: Glutamatergic transmission is an important factor in the development of neuronal death following transient cerebral ischemia. In this investigation the effects of N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists on neuronal damage were studied in rats exposed to 10 min of transient cerebral ischemia induced by bilateral common carotid occlusion combined with hypotension. The animals were treated with a blocker of the ionotropic quisqualate or α-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) receptor, 2.3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX), given postischemia as an intraperitoneal bolus dose of 30 mg kg-1 followed by an intravenous infusion of 75 μg min-1 for 6 h, or with the noncompetitive NMDA receptor blocker dizocilpine (MK-801) given 1 mg kg-1 i.p. at recirculation and 3 h postischemia, or with the competitive NMDA receptor antagonist DL-(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid (CGP 40116), 5 mg kg-1, given intraperitoneally at recirculation. Treatment with NBQX provided a significant reduction of neuronal damage in the hippocampal CA1 area by 44-69%, with the largest relative decrease in the temporal part of the hippocampus. In neocortex a significant decrease in the number of necrotic neurons was also noted. No protection could be seen following postischemic treatment with dizocilpine or CGP 40116. Our data demonstrate that AMPA but not NMDA receptor antagonists decrease neuronal damage following transient severe cerebral ischemia in the rat and that the protection by NBQX may be dependent on the severity of the ischemic insult. We propose that the AMPA receptor-mediated neurotoxicity could be due to ischemia-induced changes in the control mechanisms of AMPA receptor-coupled processes or to changes of AMPA receptor characteristics. (Less)
Journal Article•
TL;DR: The production rate of cystatin C is remarkably constant and its plasma concentration can therefore be used as a reliable measure of the glomerular filtration rate (GFR), which is more closely correlated to the GFR than the plasma levels of creatinine and all other investigated low molecular weight proteins.
Abstract: Cystatin C, a 13 kDa-protein, is produced by most nucleated cells and is catabolized by the renal tubular cells after passing the glomerular filter. It belongs to the family 2 of the cystatin superfamily of proteins. The function of cystatin C is to regulate the activity of cysteine proteinases and cystatin C seems to be the main cysteine proteinase inhibitor of most investigated human biological fluids. Its normal level in plasma is 0.8-2.5 mg/l, in cerebrospinal fluid 4-14 mg/l and in urine 0.03-0.3 mg/l. The production rate of cystatin C is remarkably constant and its plasma concentration can therefore be used as a reliable measure of the glomerular filtration rate (GFR). Indeed, the cystatin C plasma concentration is more closely correlated to the GFR than the plasma levels of creatinine and all other investigated low molecular weight proteins, including beta 2-microglobulin and retinol binding protein. Protein HC, alias alpha 1-microglobulin, is produced by the liver as a 27 kDa-glycoprotein. It belongs to the lipocalin superfamily of hydrophobic ligand binding proteins and more than 50% of the normal plasma amount of protein HC is present as a high molecular weight HC-IgA complex carrying antibody activity. The plasma concentration of free protein HC is, in contrast to that of HC-IgA, mainly determined by the GFR. The normal values for the plasma concentrations of HC-IgA and free protein HC are 36-620 mg/l and 14-26 mg/l, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
01 Jan 1992
TL;DR: In the first quantization formalism of quantum mechanics, observables are represented by operators and the wave functions are normal functions as discussed by the authors, and in the method of second quantization, the wave function is also expressed in terms of operators.
Abstract: In the usual formalism of quantum mechanics, the first quantization formalism, observables are represented by operators and the wave functions are normal functions. In the method of second quantization, the wave functions are also expressed in terms of operators. The formalism starts with the introduction of an abstract vector space, the Fock space. The basis vectors of the Fock space are occupation number vectors, with each vector defined by a set of occupation numbers (0 or 1 for fermions). An occupation number vector represents a Slater determinant with each occupation number giving the occupation of given spin orbital. Creation and annihilation operators that respectively adds and removes electrons are then introduced. Representations of usual operators are expressed in terms of the very same operators.
TL;DR: Charophytes have disappeared from several enriched lakes in Scania (southern Sweden) since the 1940s, and it is suggested that these species are unable to grow in very shallow water because of damage by ice and wave action.
Abstract: SUMMARY
1. Charophytes have disappeared from several enriched lakes in Scania (southern Sweden) since the 1940s. Poor light conditions, rather than a toxic effect of phosphorus or negative impact of fish, are the most probable reason for this decline.
2. Small species of charophytes (shoot diameter 0.5–1.0 mm), which are able to form dense, low mats, still occur in eutrophic lakes with high phosphorus concentrations, but are restricted to areas of shallow water. In contrast, large species (shoot diameter
1–4 mm) have totally disappeared from the most turbid lakes. I suggest that these species are unable to grow in very shallow water because of damage by ice and wave action.
3. Maximum depth distribution (ze) and Secchi depth (D) were measured in Scanian lakes for both charophytes and angiosperms and combined with data obtained from Chambers & Kalff (1985). According to the combined data, zc and D are closely correlated with each other for both angiosperms and charophytes.
4. The zc of charophytes is higher than zc of angiosperms in clear lakes but lower in turbid lakes. Higher zc of angiosperms in the most turbid lakes is explained by special adaptations of these species to poor light availability (shoot elongation, canopy formation, rapid growth during spring).
TL;DR: It is demonstrated that the 12q breakpoint of the t( 12;16) in MLS differs from those in the other tumors investigated, even in cases with no cytogenetically visible differences in breakpoint position, that CHOP rearrangement is specific for MLS, and that the breakpoints cluster to the 5′ region of the gene.
Abstract: Most myxoid liposarcomas (MLS) are characterized cytogenetically by a t(12;16)(q13;p11) It is reasonable to assume that this translocation corresponds to the consistent rearrangement of one or two genes in 12q13 and/or 16p11, and that the loci thus affected are important in the normal control of fat cell differentiation and proliferation We have used Southern blot technique to test whether a gene of the CCAAT/enhancer binding protein (C/EBP) family, CHOP, which maps to 12q13 and is assumed to be involved in adipocyte differentiation, could be the 12q gene in question Using a cDNA probe that spans the CHOP coding region, we detected one rearranged and one wild type allele in nine of nine MLS with t(12;16) Using PCR generated, site-specific probes corresponding to the non-coding exons 1 and 2 and intron 2 of CHOP, rearrangements in five of seven tumors mapped to the 24 and 16 kbp PstI fragments that contain the first two exons and introns of the gene and the upstream promoter region In contrast to the findings in MLS, no tumor without a t(12;16) exhibited aberrant CHOP restriction digest patterns These tumors included one highly differentiated liposarcoma with abnormal karyotype but no involvement of 12q13, seven lipomas with various cytogenetic aberrations of 12q13-15, two uterine leiomyomas with t(12;14) (q14-15;q23-24), and one hemangiopericytoma and one chondroma, both of which also had 12q13 changes(ABSTRACT TRUNCATED AT 250 WORDS)