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Biomedical subjects

K Lindström

Publications and source records attributed to K Lindström.

At least 73 records · Page 4Linked to original sources
PubMed1996

Blood group glycosphingolipid expression in kidney of an individual with the rare blood group A1 Le(a-b+) p phenotype: absence of blood group structures based on the globoseries.

Total neutral glycolipid fractions were isolated from kidney and ureter tissue obtained at autopsy of an individual of the rare blood group A1 Le(a-b+) p. The amount of glycolipids isolated were 3.7 and 2.5 mg g-1 dry tissue weight for the kidney and ureter tissue, which is in the range of reference blood group P kidneys. Part of the kidney glycolipid fraction was subfractionated by HPLC. Glycolipid compounds were structurally characterized by thin-layer chromatography (chemical detection and immunostaining with monoclonal antibodies), proton NMR spectroscopy and mass spectrometry. Globotriaosyl- and globotetraosyl-ceramides, which are the major compounds in kidneys of P individuals, were absent in the p kidney, and a comparatively increased amount of monoglycosyl- and lactosylceramides was found. A shift to longer fatty acyl chains in the ceramide part of lactosylceramides was noted. Elongated globoseries compounds with five to seven sugar residues, including the blood group A type 4 chain structure, were lacking. A slight increase in neolactotetraosyl- and blood group X pentaglycosyl-ceramides was noticed. The study confirms an enzymatic block in the conversion of lactosylceramide to elongated globoseries compounds in the kidney tissue similar to that of erythrocytes of p individuals.

Animals↗
PubMed1996

Adenosine A1 and A2A receptors and nitrobenzylthioinosine-sensitive transporters in gerbil brain: no changes following long-term treatment with the adenosine transport inhibitor propentofylline.

There is evidence that adenosine is an endogenous neuroprotective substance in the gerbil and that propentofylline, a novel xanthine derivative that acts as a transport inhibitor, exerts part of its neuroprotective activity in this species by enhancing adenosine actions. Using autoradiography we have examined the distribution of adenosine A1 and A2A receptors and of equilibrative adenosine transporters in gerbil brain as well as the possible changes induced by repeated treatment with propentofylline. Nucleoside transporters, studied by [3H]NBMPR binding, were found to be widely distributed in the gerbil brain, with no clear relationship to the distribution of adenosine receptors. Adenosine A2A receptors, studied by [3H]CGS 21680 binding and by in situ hybridization, were found to be present in intrinsic neurons in the caudate putamen, nucleus accumbens and tuberculum olfactorium. Adenosine A1 receptors were studied by examining the binding of [3H]CHA, an agonist, and [3H]DPCPX, an antagonist. There was an overall similarity in the distribution of binding sites for these two ligands, and a similarity with the distribution in the rat. However, the antagonist was found to label certain structures, especially white matter structures, more than the agonist. It is argued that these binding sites for antagonists represent receptors that are in transit from the site of synthesis in the perikaryon to the destination in the nerve terminal, and are not coupled to G proteins. There were no differences in the binding of any of these ligands or in A2A mRNA following 2 weeks' treatment with propentofylline, indicating that the drug has minimal effects on adenosine mechanisms under basal physiological conditions. This also suggests that tolerance to adenosine-related effects of the drug is less likely to occur.

Adenosine↗
PubMed1996

Acute effects of C-peptide on the microvasculature of isolated perfused skeletal muscles and kidneys in rat.

The C-peptide has recently been suggested to have beneficial effects in several organs and improve glycaemic control in human type I diabetes, while there were no such effects in healthy controls. The exact mechanisms behind these effects are, however, not clear. In an attempt to study the actions of C-peptide on the microvasculature in normal rats during more controlled conditions, isolated rat hindquarters and kidneys were perfused with albumin solutions in order to obtain low basal concentrations of C-peptide. In rat hindquarters, infusion of C-peptide significantly increased the capillary filtration coefficients (CFC) from 0.035 +/- 0.002 to 0.044 +/- 0.002 mL min-1 100 g-1 mmHg-1 (P < 0.001, n = 9) and the permeability surface area product (PS) for vitamin B12 from 3.48 +/- 0.29 to 4.02 +/- 0.37 mL min-1 100 g-1 (P < 0.01, n = 6). Addition of C-peptide to the perfusate during infusion of sodium nitroprusside did not induce any additional alteration of CFC or PS. The vascular resistance was slightly decreased from 2.74 +/- 0.17 to 2.64 +/- 0.17 mmHg min 100 g mL-1 (P < 0.01, n = 9). These effects of C-peptide are compatible with increases in capillary surface area without alteration of the permeability per se. In isolated rat kidneys perfused at low temperature (8 degrees C) prepared to inhibit all metabolic processes. C-peptide induced no changes in glomerular filtration rate, total vascular resistance or fractional albumin clearance. Therefore, C-peptide causes active vasodilation of the normothermic microvasculature and hence recruitment of capillaries. These findings support the previous observations in man that C-peptide indeed has biological effects.

Animals↗
PubMed1996

Impaired glomerular permselectivity for albumin in chemically medullectomized WKY rats.

Chemical renal medullectomy with 2-bromo-ethylamine hydrobromide (BEA) has been used to study the importance of the renal medulla in blood pressure regulation. However, conclusive evidence as to whether BEA treatment affects the glomerular barrier is lacking. In the present study, the effects of BEA upon glomerular permselectivity for albumin were studied using isolated kidneys (IPK) perfused at a low temperature (8 degrees C) to inhibit tubular reabsorption of proteins. Sixteen WKY rats (WB) received an i.v. injection of BEA (150 mg kg-1) while 10 rats served as controls (WC). Volume balance, urinary osmolality and creatinine clearance (GFR) were measured in metabolic cages. Acute paired experiments (n = 9) were performed 5-7 weeks after BEA. The rats were anaesthetized and the total in vivo albumin excretion was recorded. The kidneys were then isolated and perfused for measurements of inulin clearance (GFR) and fractional albumin clearance without tubular reabsorption of protein. The nine BEA treated rats showed polyuria and hypoosmotic urine. In vivo GFR was lower in the BEA treated groups when measured with creatinine clearance (459 +/- 22 vs. 213 +/- 41 microL min-1 100 g-1 body wt, P < 0.001), while GFR was not significantly changed in the IPK (WC = 135 +/- 27, WB = 92 +/- 14 microL min-1 100 g-1 body wt, n.s.) when perfused at identical pressures. The fractional albumin clearance was increased three times in the BEA group (WB = 9.6 +/- 3.4/1000, P < 0.05). Moreover, albumin excretion in vivo was similar in the two groups despite low GFR in the BEA group. We conclude that BEA treatment affects glomerular permselectivity for albumin.

Albumins↗
PubMed1996

Assessment of competitiveness of rhizobia infecting Galega orientalis on the basis of plant yield, nodulation, and strain identification by antibiotic resistance and PCR.

Competition between effective and ineffective Rhizobium galegae strains nodulating Galega orientalis was examined on the basis of plant growth, nodulation, antibiotic resistance, and PCR results. In a preliminary experiment in Leonard's jars, ineffective R. galegae strains HAMBI 1207 and HAMBI 1209 competed in similar manners with the effective strain R. galegae HAMBI 1174. In a pot experiment, soil was inoculated with 0 to 10(5) HAMBI 1207 cells per g before G. orientalis was sown. Seeds of G. orientalis were surface inoculated with 2 x 10(4) and 2 x 10(5) cells of HAMBI 1174 per seed (which represent half and fivefold the commercially recommended amount of inoculant, respectively). Plant yield and nodulation by the effective strain were significantly reduced, with as few as 10(2) ineffective rhizobia per g of soil, and the inoculation response was not improved by the 10-fold greater dose of the inoculant. Bacteria occupying the nodules were identified by antibiotic resistance and PCR with primers specific for R. galegae HAMBI 1174, R. galegae, and genes coding for bacterial 16S rRNA (bacterial 16S rDNA). Sixty-two large nodules examined were occupied by the effective strain HAMBI 1174, as proven by antibiotic resistance and amplification of the strain-specific fragment. From 20 small nodules, only the species-specific fragment could be amplified, and isolated bacteria had the same antibiotic resistance and 16S PCR restriction pattern as strain HAMBI 1207. PCR with our strain-specific and species-specific primers provides a powerful tool for strain identification of R. galegae directly from nodules without genetic modification of the bacteria.

Base Sequence↗
PubMed1996

Results from an intervention programme dealing with cardiovascular risk factors. Experiences from a study of men aged 33-42 in Habo, Sweden.

OBJECTIVE: To evaluate the long-term effect of a health examination and intervention programme in a Swedish community. DESIGN: A health examination was carried out with the purpose of improving cardiovascular risk factors. A health profile was created as an educational tool, by means of which a nurse discussed the results of the health examination with the participants. Follow-up studies were carried out after 1 year and after 3-6 years. PARTICIPANTS: All men aged 33-42 living in a Swedish community (Habo) were invited to the health examination. Altogether 652 participated, corresponding to a participation rate of 86.1%. MAIN RESULTS: In the 1-year follow-up study, improvement with respect to cardiovascular risk factors was seen in a high-risk group (n = 161) for systolic blood pressure and lifestyle factors such as alcohol consumption, smoking, mental stress, mental health, and for the sum of risk points according to the health profile. Corresponding improvement was not seen in other men of similar age in the same community who had not participated in the health survey. In the 3-6 year follow-up only minor improvements remained, mainly for blood pressure and sum of risk points. CONCLUSION: Even if the results are rather promising in the short run, it seems urgent to make the methods for improving cardiovascular risk factors better, especially with regard to long-term results.

Adult↗
PubMed1995

Chemical characterization of two lipopolysaccharide species isolated from Rhizobium loti NZP2213.

Phenol-water extraction of Rhizobium loti NZP2213 cells allowed a simultaneous isolation of two structurally different lipopolysaccharides from the aqueous (LPS-W) and phenol (LPS-P) phase that differed in their sodium deoxycholate-PAGE pattern and composition. LPS-W showed a profile indicating an R-type LPS; LPS-P had a cluster of poorly resolved bands in the high-molecular-weight region. LPS-P contained large amounts of 6-deoxy-L-talose (6dTal), and a small amount of 2-O-methyl-6-deoxy-talose (molar ratio approximately 30:1), both of which were completely absent in LPS-W. Methylation analysis gave only one major product, 2,4-di-O-methyl-6dTal, indicating that the O-chain is composed of a homopolymer of 1,3-linked 6dTal, having the methylated 6dTal (2-O-Me-6dTal) probably localized at the non-reducing end of the O-chain. This homopolymeric O-chain was additionally O-acetylated, as evidenced by GC-MS and by 13C NMR analysis. The lipid A moieties of both LPS-W and LPS-P showed almost identical composition, with six different 3-OH fatty acids and with two, so far not described, long-chain 4-oxo-fatty acids, all being amide-linked, and with 27-OH-28:0 as the main ester-linked fatty acid. Lipid A was of the lipid ADAG-type, i.e., having a (phosphorylated) 2,3-diamino-2,3-dideoxy-D-glucose-containing lipid A backbone. Lipid ADAG is widespread among species of the alpha-2 group of Proteobacteria, but has so far not been encountered in any other rhizobial or agrobacterial species.

Carbohydrates↗
PubMed1995

Blood perfusion measurement with multifrequency Doppler ultrasound.

Due to its sensitivity to measurement artifacts, the ultrasonic Doppler technique has not yet become a clinically useful tool for blood perfusion measurements. One of these measurement artifacts is caused by ultrasonic wave interference in combination with the small changes of structures inside the ultrasonic field. These changes are a result of variations in blood pressure, small movements in muscles, and involuntary movements of the transducer. The changes alter the ultrasonic interference pattern, causing fluctuations in the measured perfusion value. In this paper a new multifrequency technique for blood perfusion measurement is presented. The technique is based on a multifrequency setup, with four ultrasonic frequencies simultaneously transmitted with the same transducer. It is shown that by averaging the measured values obtained from each frequency, the sensitivity to ultrasonic wave interference can be lessened. Measurement results from both in vitro and in vivo experiments are presented.

Artifacts↗
PubMed1995

Interrelation between risk factors for cardiovascular disease in men aged 33-42. A study from Habo in Skaraborg County, Sweden.

OBJECTIVES: The main purpose was to study associations between different risk factors for coronary heart disease in order to find out whether such associations already exist during the fourth decade of life. SETTING: A study carried out by the primary healthcare staff in the community of Habo in Skaraborg County in south-western Sweden. SUBJECTS: All men living in Habo aged 33-42 years who were willing to participate in the study--in total 652 men (participation rate 86%). MAIN OUTCOME MEASURES: Risk factors for coronary heart disease considered as markers of lifestyle: body-mass index as a measure of general obesity, waist-to-hip circumference ratio as a measure of central obesity, arterial blood pressure, serum cholesterol concentration and serum triglyceride concentration. RESULTS: There were statistically significant correlations between all the factors analysed including anthropometric data, blood pressure and serum lipids. CONCLUSIONS: The results indicate associations between different risk factors at an early age and emphasises the need for a multifactorial view on risk as early as at the ages which were the focus of this study.

Adult↗
PubMed1995

Identification of Rhizobium spp. in peat-based inoculants by DNA hybridization and PCR and its application in inoculant quality control.

Procedures based on DNA hybridization and PCR were developed for quality control of Rhizobium inoculants. Inoculants for pea and goat's rue were produced by Elomestari Ltd., Juva, Finland, in sterile dry fine peat by the standard procedure used by the company. The inoculants contained Rhizobium galegae HAMBI 1174 and HAMBI 1207 and an R. leguminosarum biovar vicia strain, 16HSA, either solely or in combinations of two or three strains. DNA was isolated from 1-g samples of each peat inoculant and analyzed by nonradioactive DNA-DNA hybridization and by PCR. The hybridization probes were total DNAs from pure cultures of R. galegae HAMBI 1207 and R. leguminosarum biovar viciae 16HSA and a 264-bp strain-specific fragment from the genome of R. galegae HAMBI 1174. The total DNA probes distinguished inoculants containing R. galegae or R. leguminosarum, and the strain-specific probe distinguished inoculants containing R. galegae HAMBI 1174. The hybridization results for R. galegae were verified in a PCR experiment by amplifying an R. galegae species-specific fragment and an R. galegae HAMBI 1174 strain-specific fragment in the same reaction. When suitable probes and primers are available, the methods described here offer promising alternatives for the quality control of peat-based inoculants.

Base Sequence↗
PubMed1995

The role of psychological distress and personality in the incidence of sciatic pain among working men.

OBJECTIVES: The role of personality characteristics and psychological distress in the incidence of sciatic pain was investigated in a 3-year prospective study. METHODS: The study population consisted of 1149 Finnish men aged 25 through 49 years (387 machine operators, 336 carpenters, and 426 office workers) with no history of sciatic pain at the beginning of follow-up. The psychological distress and personality characteristics were assessed by the Middlesex Hospital Questionnaire and the Maudsley Personality Inventory. RESULTS: The 3-year cumulative incidence rate for sciatic pain was 22% among the machine operators, 24% among the carpenters, and 14% among the office workers. The multivariate analysis of psychological factors, taking into account individual and occupational factors, showed that only hysteria was significantly associated with the incidence of sciatic pain among the blue-collar workers. Among the white-collar workers, none of the psychological dimensions were associated with sciatic pain. CONCLUSIONS: These results are in accordance with previous relationships found between hysteria and low-back disorders. Further follow-up investigations are needed to elucidate the role of psychological factors in the occurrence of back problems.

Adult↗
PubMed1995

Medical audit used for estimation of optimum level of outpatient care.

OBJECTIVE: To create a model for determining the optimum level of outpatient medical care and to determine this level. DESIGN: Expert committees were established comprising one or two hospital physicians and two general practitioners who checked medical records for all outpatient visits to doctors made by a defined population during a defined period of time. The determination of optimum level was made blindly by each member of the expert committee. SETTING AND PARTICIPANTS: The study comprised all visits to physicians during 10 weeks, in total more than 4,000, made by the people in a Swedish community, of which 2,084 were randomized. RESULTS: Total agreement between the members of the committee was initially reached for 84% of the visits and, after a common discussion between the committee members, for 99%. A general practitioner was considered to be the optimum level of care for 76% of the patients in the total series, in the upper ages (above 80) for about 85%. CONCLUSION: This method seemed suitable for determining the optimum level of care in a population and may be of value when planning for an optimum health care service. Based on the results from our study it seems reasonable to assume that general practitioners whose training corresponds to that of Swedish ones are competent to treat about 75% of all consultations.

Adolescent↗
PubMed1994

Changes in adenosine receptors in the neonatal rat brain following hypoxic ischemia.

We used quantitative in situ hybridization and receptor autoradiography to study changes in adenosine receptors following hypoxia-ischemia (H-I) in the neonatal rat brain. Seven-day-old rat pups were subjected to a unilateral ligation of the common carotid artery followed by a 2 h 15 min hypoxic period (7.7% O2 in N2). Adenosine A1 receptor mRNA in cortex and several parts of hippocampus, and A2a mRNA was decreased in the ligated hemisphere 0 h, 1 h and 2 h following hypoxia. The binding of the A1 receptor selective antagonist [3H]8-cyclopentyl-1,3-dipropylxanthine (DPCPX) in the presence or in the absence of GTP decreased immediately after the hypoxic period in both hemispheres and returned thereafter gradually towards control. These results show that there are rapid changes in A1 receptor number on both sides of the brain, and of adenosine A1 and A2a receptor mRNA in the hemisphere that would later develop infarction. Decreases in adenosine receptors may worsen H-I brain damage and have consequences for the use of adenosine directed therapy.

Animals↗
PubMed1994

Differences in the regional and cellular localization of c-fos messenger RNA induced by amphetamine, cocaine and caffeine in the rat.

Male rats were treated i.p. with either 5 mg/kg amphetamine, 3 and 30 mg/kg cocaine or 100 mg/kg caffeine and killed after 30 min. Brains were sectioned and processed for radioactive in situ hybridization histochemistry for the labelling of either c-fos, enkephalin, substance P, neurokinin B, choline acetyltransferase, somatostatin or adenosine A2A receptor messenger RNA. The distribution of c-fos messenger RNA was investigated both at the regional level using film autoradiography, and at the cellular level using emulsion autoradiography. All drug treatments except 3 mg/kg cocaine induced an increased level of c-fos messenger RNA in cells that had a neuron-like morphology. The cells that contained the c-fos messenger RNA were identified by making pairs of 5-microns sections in which one section was processed for c-fos messenger RNA and the other was processed for one of the other messenger RNA species. After amphetamine treatment, only some 10% of the cells in the striatum were labelled, and to a variable extent. Instead there was prominent labelling of a band in the cortex that runs parallel to the cortical surface. There was also a moderate degree of labelling in the nucleus accumbens. c-fos-positive cells were substance P-positive and negative for enkephalin or A2A receptor messenger RNA. Cocaine (30 mg/kg) induced a modest labelling in the caudate-putamen, as well as in the accumbens. With cocaine treatment (30 mg/kg), about 30% of striatal neuron-like cells were c-fos labelled. Most c-fos-positive cells were substance P-positive, but none of the c-fos-positive cells were enkephalin-positive or A2A-receptor-positive. Cocaine (3 mg/kg) had no significant effect on c-fos. Caffeine gave rise to a strong hybridization signal in the caudate-putamen, particularly the dorsolateral part. No other region examined differed significantly from control. With caffeine treatment, about 73% of neuron-like cells were c-fos labelled in the lateral striatum, but labelling was much less pronounced in the medial part or in the accumbens. c-fos-labelled cells were found in enkephalin-positive and enkephalin-negative, substance P-positive and substance P-negative, neurokinin B-positive and neurokinin B-negative groups. No choline acetyltransferase-positive or somatostatin-positive cells were found that were also c-fos-positive with any of the treatments. We conclude that each of the different CNS stimulant drugs induces a highly specific pattern of c-fos messenger RNA.(ABSTRACT TRUNCATED AT 400 WORDS)

Amphetamine↗
PubMed1994

Propentofylline and other adenosine transport inhibitors increase the efflux of adenosine following electrical or metabolic stimulation of rat hippocampal slices.

Propentofylline is a novel neuroprotective agent that has been shown to act as an adenosine transport inhibitor as well as an adenosine receptor antagonist. In the present series of experiments we have compared the effects of propentofylline with those of known adenosine transport inhibitors and receptor antagonists on the formation of adenosine in rat hippocampal slices. The ATP stores were labeled by incubating the slices with [3H]adenine. The total 3H overflow and the overflow of endogenous and 3H-labeled adenosine, inosine, and hypoxanthine were measured. Adenosine release, secondary to ATP breakdown, was induced both by hypoxia/hypoglycemia and by electrical field stimulation. Propentofylline (20-500 microM) increased the release of endogenous and radiolabeled adenosine, without increasing the total release of purines. Thus, the drug altered the pattern of released purines, i.e., increasing adenosine and decreasing inosine and hypoxanthine. This pattern, which was observed when purine release was induced both by electrical field stimulation and by hypoxia/hypoglycemia, was shared by the nucleoside transport inhibitor dipyridamole (1 microM) and by mioflazine (1 microM) and nitrobenzylthioinosine (1 microM). By contrast, other xanthines, including theophylline (100 microM) and 8-cyclopentyltheophylline (10 microM), enprofylline (100 microM), or torbafylline (300 microM), if anything, increased the total release of purines without alterations of the pattern of release. These results indicate that nucleoside transport inhibitors can decrease the release of purines from cells and at the same time increase the concentration of extracellular adenosine, possibly by preventing its uptake and subsequent metabolism. This change in purine metabolism may be beneficial with regard to cell damage after ischemia. The results also indicate that propentofylline behaves in such a potentially beneficial manner.

Adenosine↗
PubMed1994

A current injecting device for electrical impedance tomography.

Electrical impedance tomography (EIT) has to be improved in order to become an accepted diagnostic technique in clinical use. The aim of this study is to improve the hardware of this technique and preferably upgrade the current injecting device. Instead of using a constant current generator the idea is to implement a voltage source and measure current accurately, in order to improve the resolution in the image. The performance of such a device is analysed, particularly concerning theoretical and practical limitations. The amplitude and phase accuracy, noise and settling time are measured and presented in diagrams. The results show that improvements are possible to achieve and that such a device will improve the stability of an EIT system and the image quality.

Electric Impedance↗