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Biomedical subjects

A Persson

Publications and source records attributed to A Persson.

At least 109 records · Page 6Linked to original sources
PubMed1990

Surfactant protein D is a divalent cation-dependent carbohydrate-binding protein.

Surfactant protein D (SP-D, CP4) is a collagenous surfactant-associated glycoprotein synthesized by lung type II epithelial cells. SP-D can be selectively and efficiently eluted from isolated rat surfactant with glucose, maltose, and certain other saccharides. We therefore examined the ability of the purified protein to interact with carbohydrates in vitro. Saccharide-substituted bovine serum albumins (BSA neoglycoproteins) were adsorbed to plastic wells, and binding of purified SP-D was quantified with monospecific antibodies to SP-D using an indirect immunoassay. SP-D showed specific calcium-dependent binding to alpha-D-glucosidophenyl isothiocyanate-BSA and maltosyl-BSA, but negligible binding to beta-D-glucosidophenyl isothiocyanate-BSA or unconjugated BSA. The most efficient inhibitors of SP-D binding were alpha-glucosyl-containing saccharides (e.g. isomaltose, maltose, malotriose). SP-D showed quantitative binding to maltosyl-agarose and was specifically eluted with maltose or EDTA. High affinity binding to maltosyl-BSA was also demonstrated using a solution-phase polyethylene glycol precipitation assay. These studies demonstrate that SP-D is a calcium dependent lectin-like protein and that the association of SP-D with surfactant is mediated by carbohydrate-dependent interactions with specificity for alpha-glucosyl residues.

Animals↗
PubMed1990

Maps of receptor binding parameters in the human brain--a kinetic analysis of PET measurements.

A kinetic method is described for the estimation of neuroreceptor density as well as the rate constants for association and dissociation of rapidly equilibrating radioligands. The method is exemplified by positron emission tomographic measurements of the human brain using 11C-raclopride, a D 2 dopamine receptor antagonist, and 11C-Ro 15-1788, a benzodiazepine receptor antagonist. Using a linear non iterative algorithm, regional binding characteristics were calculated and displayed pixel by pixel in brain maps. Data from repeated experiments on the same subject with different amounts of the unlabeled ligand were utilized. The binding characteristics were determined according to a two step procedure in which the time course of the free radioligand concentration was estimated from a reference region considered to be free of specific receptor binding sites. Alternative methods to determine the concentration of free radioligand are discussed.

Algorithms↗
PubMed1990

The metabolism and bioavailability of morphine in patients with severe liver cirrhosis.

1. The oral and intravenous kinetics of morphine were investigated in seven cirrhotic patients with a history of encephalopathy. The plasma concentrations of morphine and its metabolites morphine-3 (M3G) and morphine-6 (M6G) were measured by h.p.l.c. 2. The mean terminal elimination half-life of morphine was 4.2 h (95% CI 3.6-4.8) the mean volume of distribution was 4.1 l kg-1 (95% CI 2.9-5.4) and the mean plasma clearance was 11.4 ml min-1 kg-1 (95% CI 8.1-14.7). The mean oral bioavailability was 101% (95% CI 56-147). 3. The plasma clearance of morphine was significantly lower, its terminal elimination half-life longer and its oral bioavailability greater in the cirrhotic patients compared with patients with normal liver function. The metabolic ratio M3G/morphine was significantly lower in the cirrhotic patients than in control subjects after oral dosing, but did not differ after intravenous dosing. 4. The average urinary recoveries of morphine plus M3G and M6G were 49.9% after i.v. and 57.7% after oral administration. There were no statistically significant differences in the urinary recovery between the two routes of administration or between the cirrhotic patients and controls. 5. Specific changes in the EEG pattern could not be detected after intravenous dosage. 6. The metabolism of morphine is impaired significantly in patients with severe cirrhosis. Clinically important findings were a high oral bioavailability and a long elimination half-life. These findings call for cautious dosing of oral and intravenous morphine in patients with severe end stage liver disease.

Administration, Oral↗
PubMed1990

Temperature dependence of [3H]Ro 15-1788 binding to benzodiazepine receptors in human postmortem brain homogenates.

The temperature dependence of in vitro binding of [3H]Ro 15-1788 to benzodiazepine receptors in human postmortem neocortex and neocerebellum homogenates was studied. An increase of the equilibrium dissociation constants (KD) from 1.40 nmol/L and 1.04 nmol/L at 4 degrees C to 6.10 nmol/L and 8.91 nmol/L at 37 degrees C was found for neocortex and neocerebellum, respectively. In contrast, maximal binding (Bmax) remained in the range of 30-35 fmol/mg for neocortex and 24-27 fmol/mg of tissue (wet weight) for neocerebellum at all the temperatures. The KD of 6.10 nmol/L for neocortex at 37 degrees C in vitro is of the same order as the KD of 10 nmol/L obtained by positron emission tomography for [11C]Ro 15-1788 binding to benzodiazepine receptors in the human neocortex in vivo. The differences in KD between in vitro and in vivo benzodiazepine receptor binding to human neocortex and cerebellum seem to be due at least partially to temperature differences of in vitro and in vivo studies.

Brain↗
PubMed1990

Physiological and Morphological Changes Induced by Nutrient Limitation of Pseudomonas fluorescens 378 in Continuous Culture.

Pseudomonas fluorescens 378 was studied in continuous culture at a dilution rate of 0.05 or 0.15 h and under a limitation of carbon/energy, nitrogen, phosphorus, iron(III), or oxygen. Cultures were examined for nutritional consumption, production of biosurfactant AP-6 and lipase, and electron microscopy morphology. Morphological features were lysis and plasmolysis of the cells, vacuoles in the cells, granules in cell nuclei, and DNA coagulation during transmission electron microscopy preparation. Biosurfactant and lipase production were lost after 8 to 15 retention times, but under iron limitation and at low dilution rate they were maintained for more than 30 retention times. Consumption of nutrients varied between different cultures. Between 2.4 and 6.0 g of succinic acid per g (dry weight) was consumed; the highest value was obtained under phosphorus limitation. The uptake of nitrogen was mostly about 0.16 g/g (dry weight), and that of phosphorus varied between 13 and 58 mg/g (dry weight). Phosphorus-limited cells reduced their phosphorus consumption by at least 50% compared with other limitations. Cell morphology varied among different cultures. Up to 25% cell lysis occurred at the higher dilution rate. The frequencies of plasmolysis varied between 0 and 85%. Granules in nuclei were found in 65 to 100% of the cells. Vacuoles appeared mostly in low numbers, but at the lower dilution rate under phosphorus or iron limitation the frequencies increased to between 25 and 85%. At high dilution rate, the DNA coagulated in 30 to 70% of the cells. Multivariate data analysis demonstrated a general difference between the two tested dilution rates; i.e., both nutritional and morphological features differed more between the two tested dilution rates than between the different limitations. Cultures at the lower dilution rate changed more with time; this was especially pronounced for phosphorus or iron limitation. The data analysis also showed a correlation between plasmolysis or vacuoles in the cells and an increased carbon uptake under phosphorus limitation.

Journal Article↗
PubMed1990

Vocal dysfunction following cricothyroidotomy: a prospective study.

Voice dysfunction is a known consequence of cricothyroidotomy, but few detailed analyses have been published. This study reports an investigation of voice function in 19 patients who underwent cricothyroidotomy during a 12-month period (54 were patients operated on, 29 survived the primary disease or injury, and 19 agreed to participate in the investigation). The patients were interviewed regarding signs of dysfunction of the cricothyroid muscles, or a diminished external tensor effect on the vocal folds. Laryngoscopy with a magnifying-angled endoscope, stroboscopy, phonetography, determination of mean speaking fundamental frequency, perceptual analysis of the voice, and electromyogram of the cricothyroid muscle were all performed. Four patients had signs of diminished external tensor effect on the vocal folds (mild or moderate voice dysfunction), 5 patients had other voice disorders, and 10 were classified as having normal voice. Elective cricothyroidotomy should be avoided in patients with professional or other activities that place heavy demands on the voice.

Adult↗
PubMed1990

Recent advances in psychiatric brain imaging.

The characterization of neuroreceptor functions in the living human brain has hitherto been hampered by the lack of techniques useful for the measurement of physiologic events within the human brain in vivo. Recent developments in positron emission tomography (PET) has allowed the quantitative tracing of intravenously administered molecules within tissue compartments of the brain. Using ligands binding with high affinity to cerebral neuroreceptors it has been possible to examine not only the distribution but also some quantitative aspects of brain neuroreceptors in living human subjects by the PET technique. By the selection of highly selective ligands for different receptor systems and by labeling them with positron emitting isotopes as 11C or 18F, methods have been developed for the characterization of receptor subtypes for the endogenous ligands dopamine, serotonin, opiates, acetylcholine, glutamate and GABA. The present communication describes the use of 11C-SCH 23390 and 11C-raclopride for the analysis of D1 and D2 dopamine receptors, the benzodiazepine (BZ) antagonist 11C-Ro 15-1788 for benzodiazepine receptors and 11C-nicotine for nicotine receptors. Specificity of binding was verified by using active and inactive stereoenantiomers of the ligands. After the intravenous administration of the ligands quantitative aspects of the receptor binding was calculated using models according to equilibrium or dynamic approaches. Bmax and Kd values for D2 dopamine and BZ receptors could be determined in the brain of healthy human subjects and patients with neuropsychiatric disorders. No alteration of D2 dopamine receptors in the major basal ganglia were found in drug naive schizophrenic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzazepines↗
PubMed1990

Central nervous system complications in children treated with ciclosporin after renal transplantation.

Severe complications involving the central nervous system occurred in 7 of 36 children (19%) after renal transplantation. The children, aged 1.6-13.1 years at transplantation were treated with ciclosporin and prednisolone. Six of them had azathioprine as well. The neurological symptoms consisted of seizures, drowsiness, confusion, hallucinations, visual disturbances, and mental changes. In all cases electroencephalograms were severely pathological, showing diffuse abnormalities with or without focal abnormalities and epileptic activity. In all but one case the ciclosporin trough blood levels were within the therapeutic range. Blood glucose and electrolytes were normal. Several factors might contribute to the central nervous system complications: ciclosporin, corticosteroids, hypertension, rejection, and as yet unknown ones.

Adolescent↗
PubMed1989

Purification and biochemical characterization of CP4 (SP-D), a collagenous surfactant-associated protein.

CP4 is a collagenous glycoprotein (43 kDa, reduced) synthesized by rat type II pulmonary epithelial cells in primary culture (Persson et al., 1988). In order to better characterize this protein, CP4 was isolated from rat bronchoalveolar lavage and EDTA extracts of lung surfactant by adsorption to barium sulfate and elution with sodium citrate followed by reverse-phase HPLC. Amino acid analysis of purified CP4 demonstrated 4-hydroxyproline (Hyp), hydroxylysine (Hyl), and acid-labile components coeluting with Hyl glycosides. In addition, gas-phase amino-terminal microsequencing of two CP4 CNBr peptides demonstrated nonoverlapping collagenous sequences comprised of nine and six Gly-X-Y triplets, containing a total of four residues of Hyp and two of Hyl. There was less than 50% sequence homology of these peptides with the cDNA-derived sequence of the collagenous domain of rat SP-A. Two-dimensional IEF/SDS-PAGE resolved the protein into a charge train of basic isoforms (pI approximately 6-8), similar to those of newly synthesized CP4 and the class D surfactant proteins (Phelps & Taeusch, 1985). Gel filtration of nondenatured CP4 on 4% agarose showed a high apparent molecular mass complex comprised of disulfide-bonded trimers of the 43-kDa subunits. Antibodies to purified lavage CP4 showed specific binding to newly synthesized and surfactant-associated CP4. We propose that CP4 be designated "surfactant protein D" (SP-D) in accordance with an accepted nomenclature for surfactant-associated proteins.

Amino Acid Sequence↗
PubMed1989

Distribution of galanin-binding sites in the monkey and human telencephalon: preliminary observations.

Using X-ray film autoradiography the distribution of 125I-galanin binding sites was studied in the forebrain of monkey and man. In the monkey a high density was found in all areas of the neocortex, especially layer 4, and in certain subfields in the hippocampal region. Also in the human brain high activity was seen in neocortex, mainly layer 6 and in hippocampal areas, as well as in amygdala, piriform cortex and hypothalamus. These results suggest that the 29-amino acid peptide galanin may be involved in the regulation of higher cortical functions in primates.

Amygdala↗
PubMed1989

Nerve fibre studies in skin biopsies in peripheral neuropathies. I. Immunohistochemical analysis of neuropeptides in diabetes mellitus.

Standardised skin biopsies followed by immunohistochemical examination for the presence of terminal nerve fibres reacting for neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) were evaluated. Healthy subjects regularly displayed free nerve endings of both fibre types in the papillary and reticular dermis. Both fibre types were present close to blood vessels, while CGRP immunoreactive fibres were more often encountered near sweat gland acini compared to SP fibres. Diabetes mellitus complicated by polyneuropathy was accompanied by marked reduction of SP and CGRP reactive fibres in the dermis layers. Five type I diabetes patients without clinical or neurophysiological evidence of polyneuropathy also had reduced density of both fibre types, being significant for CGRP fibres when compared with controls. Skin biopsy with immunohistochemical staining for neuropeptides may represent a sensitive tool in evaluation of patients with peripheral neuropathies.

Adult↗
PubMed1989

Visual evoked potential--a tool in the diagnosis of hepatic encephalopathy?

Visual evoked potentials (VEP) have been suggested to be of value in the diagnosis of subclinical and mild hepatic encephalopathy. In the present study, a comparison between VEP and four psychometric tests (number connection test A and B, digit symbol and word memory test) was performed in 42 cirrhotic patients, 17 of whom had clinical signs of encephalopathy. The results were compared to sex- and age-matched healthy controls. The VEP latencies for P2 (the second positive wave) and N3 (the third negative wave) were 11% and 26% longer (P less than 0.01-0.001) in the patients than in the controls. Moreover, the latencies for N2 (the second negative wave) and P2 were longer in the encephalopathic as compared to the non-encephalopathic patients (P less than 0.05). There was a significant correlation between the latencies for N2 and number connection tests A and B and digit symbol test. However, of the patients with clinical encephalopathy, less than half had VEP latencies longer than the mean +/- 2 S.D. above those for the controls. In contrast, none of the encephalopathic patients had normal results on the psychometric tests. This study demonstrates that although statistically significant differences exist between groups of cirrhotic patients and controls, VEP is not a reliable tool for the diagnosis of encephalopathy in the individual patient.

Adult↗
PubMed1989

Parenteral nutrition in patients with liver cirrhosis. Effects on circulating levels of glucose and hormones and on cerebral function.

The effects of 2 and 5 days of total parenteral nutrition (TPN; 70 g amino-acids, 100 g fat, 150 g glucose) on carbohydrate, fat and amino-acid levels and on cerebral function were investigated in 10 patients with alcoholic cirrhosis and 7 age-matched healthy controls. The results were compared to those after a standardised oral diet. During TPN, glucose concentrations increased slightly in both groups. Insulin concentrations also rose in both groups, but the rise was more pronounced in the patients, resulting in a 10-fold difference between the two groups after 6.5 hours (patients: 281 +/- 81 U/l; controls: 28 +/- 5 U/l; p < 0.02). Glucagon increased significantly during TPN in the patients only (33%, p < 0.05). Similar but less pronounced patterns were observed after the oral diet. The basal concentrations of free fatty acids and 3-OH-butyrate were higher in the patients than in the controls. However, during both oral and parenteral nutrition, the concentrations fell in both groups. For 3-OH-butyrate the difference between the groups disappeared, while the free fatty acid levels remained higher in the patients throughout the TPN administration. Basal triglyceride levels were similar in patients and controls and rose to a similar extent in both groups during TPN. Plasma amino-acid concentrations were typical for cirrhotic patients in the basal state: low levels of the branched-chain amino-acids (BCAA) and high concentrations of the aromatic amino-acids (AAA). During TPN BCAA, as well as AAA, increased in both patients and controls, resulting in unaltered BCAA AAA ratio. All patients performed poorly on psychometric tests (Number Connection Tests A and B; Digit Symbol) before the study, indicating subclinical encephalopathy. However, no deterioration was observed in any of the tests during five days of TPN. Similarly, EEG and visual evoked potentials were unchanged during the study, demonstrating that patients with severe alcoholic liver disease tolerate a balanced intravenous nutrition without adverse effects on cerebral function.

Journal Article↗
PubMed1989

Diphtheritic neuropathy, an analysis based on muscle and nerve biopsy and repeated neurophysiological and autonomic function tests.

A patient with diphtheritic neuropathy was investigated with repeated tests of parasympathetic and sympathetic vasomotor and sudomotor functions for one year after the onset of symptoms. Somatic nerve function was tested with nerve conduction studies and an index based on ten variables was used to follow the course of the neuropathy. Sural nerve and anterior tibial muscle biopsies were performed. A severe but shortlasting impairment of the parasympathetic vagal reflex arc was found. The recovery of this function paralleled the clinical course. Sympathetic functions were normal. The neurophysiological variables of somatic nerve function showed signs of a mainly demyelinating mixed sensory/motor neuropathy. The recovery of these variables was slow. The nerve and muscle biopsies demonstrated mild changes consistent with a mixed, demyelinating, non-inflammatory neuropathy.

Arousal↗
PubMed1989

A long term study of the health status and performance of sows on different feed allowances during late pregnancy. I. Clinical observations, with special reference to agalactia post partum.

Thirty nine pairs of full sibs were investigated over 6 parities in a long term study on the effects of late pregnancy feed allowance on the occurrence of agalactia post partum and on the performance of sows and piglets. A careful examination of all sows with a rectal temperature exceeding 39.5 degrees C was performed by a veterinarian within the first 48 h after farrowing. Milk-samples were taken from sows with elevated rectal temperatures and showing clinical symptoms of agalactia. During the last 15 days of gestation the sows in the control group were fed 3.4 kg daily and the sows in the experimental group 1.0 kg daily of a commercial type of diet. In 26.6% of the farrowings in the control group the sows were agalactic whereas the corresponding figure in the experimental group was 14.4%. On clinical examination udder changes were observed in a majority of the diseased sows in both groups. However, the agalactic sows in the control group were generally more affected, with lower water and feed consumption than in the experimental group. No effects of age of the sow (parity number) or length of the gestation period on the incidence of agalactia were demonstrated. The rectal temperature of agalactic sows was significantly higher than in the healthy sows already 1 day before farrowing. The agalactic sows farrowed a larger number of stillborn piglets, which indicates an early establishment of the disease. The number of weaned piglets at 6 weeks did not differ between agalactic and healthy animals. The interval from weaning to first oestrus was not influenced by agalactia in the preceding lactation.

Animal Feed↗