Biomedical subjects

U Nilsson

Publications and source records attributed to U Nilsson.

At least 91 records · Page 5Linked to original sources

PubMed1990

Bubble and membrane oxygenators--comparison of postoperative organ dysfunction with special reference to inflammatory activity.

Bubble and membrane oxygenators (2 types of each) were compared in a randomized study of 96 patients undergoing coronary bypass grafting. Cardiac performance, assessed from postoperative need of inotropic support, was significantly better in the membrane oxygenator group. After perfusion lasting more than 2 hours, respiratory function, measured as alveolar-arterial oxygen pressure gradient, was less compromised in that group and renal function, quantified as postoperative rise of serum creatinine was less disturbed. Cerebral function, studied in terms of psychometric test results and concentration of adenylate kinase in cerebrospinal fluid, did not differ between the bubble and membrane oxygenator groups. In investigations concerning changes in inflammatory activity during bypass, complement activation could not be related to the mentioned clinical parameters. Release of the neutrophil granulocyte factors lactoferrin and myeloperoxidase was greater in the bubble oxygenator group and correlated to impaired cardiac and renal performance, but not to pulmonary or cerebral dysfunction.

Adult↗

PubMed1989

Large intramolecular movement in human complement protein C3 induced by methylamine. A small-angle scattering study using monoclonal antibodies as markers.

The reaction of methylamine with complement protein C3, which involves cleavage of a labile thiol ester bond, yields a large intramolecular rearrangement. This is shown by small-angle neutron and X-ray scattering using a Fab antibody as a marker. For the C3(Fab) 1:1 complex, the methylamine reaction yields an increase in the radius of gyration, R, from 4.6 nm to 6.0 nm. In the absence of Fab the corresponding R values increase from 4.4 nm to 5.1 nm. It is estimated that the methylamine-induced increase in R may correspond to a movement of the epitope to a position 5 nm away from the centre of gravity of the C3 molecule. In agreement with this finding, the maximum distance within the C3(Fab) complex increases from 16 nm to 22 nm as a result of the methylamine reaction. In order to explain this conformational change, it is tentatively suggested that the methylamine-induced cleavage of the C3 thiol ester bond leads to a domain rotation within the C3 molecule. In agreement with this idea, the data is consistent with a model which enables a globular domain within the molecule to rotate without redistributing the molecular mass more than that corresponding to the radii of gyration observed.

Antibodies, Monoclonal↗

PubMed1989

A knowledge-based system for automatic interpretation of an analytical profile of complement factors.

A comprehensive assay to evaluate the complement system includes functional tests of both classical and alternative pathways and immunochemical measurements of C3, C4, B, C1-INA, and C3d. The purpose of this analytical profile is to screen for rare hereditary deficiencies and acquired abnormalities of complement and to define the activation pathway in cases of complement consumptive processes. Based on several years' experience, a routine was established in our laboratory to report the data to the clinician, together with a computer-generated interpretive statement. This routine was formulated into a knowledge base by specifying a series of decision rules for each of the complement disorders. After the rules were tested and updated against some 400 complement profile analyses, reasonable analytical comments were produced by the system. This knowledge-based system for reporting and interpreting complement results offers several advantages: the interpretative work is facilitated and made more reliable; a consistent interpretative comment is generated that is recognized and therefore more meaningful for the clinician; the communication of analytical procedures and policy is enhanced.

Artificial Intelligence↗

PubMed1989

In vivo measurements of bone lead--a comparison of two x-ray fluorescence techniques used at three different bone sites.

In vivo bone lead measurements have been made on a group of about 120 people, most of whom were lead exposed workers. Two different x-ray fluorescence (XRF) techniques were used to make measurements at three bone sites. Finger lead was measured using 57Co sources, and lead measurements were made in both tibia and calcaneus with a technique based on 109Cd sources. The results of the bone lead measurements correlated strongly with each other and with the index of cumulative exposure, thus confirming the value and reliability of these in vivo measurements as a tool in the study of chronic lead exposure. Measurement precision, +/- 1 standard deviation, was highest for tibia +/- 7.4 micrograms (g bone mineral)-1, +/- 16.6 micrograms (g bone mineral)-1 for the calcaneus and lowest for phalangeal lead +/- 25.0 micrograms (g bone mineral)-1. Maximum absorbed doses to the skin were comparable for all three measurements (1-3 mGy). The mean whole body dose equivalents were all low, but that for the finger measurement, 0.1 microSv, was significantly less than for the calcaneus and tibia measurements 3-5 microSv.

Bone and Bones↗

PubMed1989

Direct communication between the left pulmonary artery and the left atrium.

A 17-year-old patient was found to have cyanosis. A right-to-left shunt was suspected clinically and confirmed by noninvasive techniques such as perfusion lung scan and contrast echocardiography. Angiography showed this shunt to be between the left pulmonary artery and the left atrium. We believe this to be the first report of a hitherto undescribed congenital anomaly.

Adolescent↗

PubMed1988

Cereal fructans: in vitro and in vivo studies on availability in rats and humans.

The bioavailability of cereal fructans (fructooligosaccharides) was investigated both in vitro and in vivo. In vitro studies indicated very slow hydrolysis by human gastric juice and by homogenate of the intestinal mucosa (rat). After intubation of fructans into the stomachs of rats, the recovery of fructans in the small intestine and colon was approximately the same as that of an unabsorbed marker (polyethylene glycol), indicating no or very low disappearance of fructans in the small intestine. In vivo studies of the small intestine in rats showed that the rate of disappearance of fructans was lower than that of mannose, which is known to be absorbed through passive diffusion. In addition the cariogenic effect of cereal fructans was compared to that of glucose. Acid formation from low molecular-weight fructans was found in human dental plaque in vitro. A mouth rinse with unfractionated fructans, containing some quantities of sucrose, fructose and glucose, resulted in relatively low pH values in human plaque in vivo, even if the decrease in pH was somewhat less pronounced when compared with a mouth rinse with glucose.

Adult↗

PubMed1988

Availability of cereal fructans and inulin in the rat intestinal tract.

The fate of cereal fructans and inulin in the gastrointestinal tract was investigated by using a rat model. Male Wistar rats received diets containing 5.0% of a preparation of cereal fructans or 4.7 or 9.4% inulin. Each diet was tested with or without Nebacitin, an antibiotic drug given to suppress the intestinal microflora. The availability of fructans in the upper gastrointestinal tract was calculated from the recovery in feces in Nebacitin-treated rats. Animals receiving cereal fructans developed diarrhea, which made it impossible to measure the bioavailability of this substrate. With inulin, the extent of digestion and absorption appeared to be 18-26%. This might, at least to some degree, be explained by hydrolysis by gastric juice in the stomach. Thus, in an in vitro assay, mild acid hydrolysis (0.05 M HCl, 37 degrees C, 120 min) converted about 8% of inulin to free fructose. The apparent digestibility of the fructans was calculated from its recovery in feces from untreated rats. Only minute amounts of fructans could be detected, hence, cereal fructans as well as inulin reaching the hindgut appeared to be almost completely fermentable.

Animals↗

PubMed1988

Use of antisera to the isolated alpha and beta subunits of C3 as probes to study functional sites present on particle-bound C3b but absent on native soluble forms of C3.

The effect of antisera to the isolated alpha and beta chains of C3 on certain C3b-dependent reactions has been studied. C5-mediated haemolysis of EAC1423b was inhibited preferentially by antiserum to the alpha chain, whereas antiserum to the beta chain inhibited the formation of C3bBb. The anti-beta chain antiserum also stabilised C3bBbP, and rendered the enzyme relatively resistant to accelerated decay in the presence of factor H. These and previous findings that anti-alpha and anti-beta IgG bind to restricted subsets of antigenic determinants on C3/C3b suggest that these antisera affect C3b function through the binding of antibodies to active binding sites exclusively exposed by bound C3b. The anti-alpha and anti-beta antibody probes are currently being further developed to verify this interpretation.

Animals↗

PubMed1988

Activation of inflammatory systems during cardiopulmonary bypass.

"Whole body inflammation" induced by cardiopulmonary bypass may play a role in the pathogenesis of postoperative complications after open-heart surgery. The inflammatory response, in terms of complement activation and release of granular proteins from neutrophil granulocytes, was investigated in six patients undergoing aortocoronary bypass surgery. Complement activation was demonstrated as well as substantially increased plasma levels of lactoferrin and myeloperoxidase--two granulocyte factors. The activation of inflammatory systems probably takes place on the artificial surfaces of the extracorporeal device. The biocompatibility of these components therefore should be further studied.

Aged↗

PubMed1987

The importance of the body's need for zinc in determining Zn availability in food: a principle demonstrated in the rat.

1. The hypothesis that the availability of zinc in a food is limited by factors in the food was tested against the hypothesis that Zn absorption is homeostatically regulated by the body according to its need for Zn. 2. The experimental model used was the short-term administration to rats of a parenteral nutrition solution with no added Zn in an attempt to increase their need for Zn in an anabolic phase. 3. The absorption and retention of 65Zn from a piece of endosperm-wheat crisp-bread in rats injected intraperitoneally with the parenteral nutrition solution was more than 40% higher than that in a control group injected with physiological saline (9 g sodium chloride/l). 4. The results indicate that the availability of Zn in the bread is not fixed but variable and dependent on the body's need for Zn.

Animals↗

PubMed1987

Hydrolysis of lactitol, maltitol and Palatinit by human intestinal biopsies.

1. The hydrolysis of sugar alcohols of the disaccharide type such as lactitol, maltitol and Palatinit (the latter an equimolar mixture of 6-O-alpha-D-glucopyranoside-D-mannitol and 6-O-alpha-D-glucopyranoside-D-sorbitol) by homogenates of human intestinal biopsies were compared with corresponding natural disaccharides such as lactose, maltose and isomaltose. Seven of the human biopsies were normal with regard to their disaccharidase activities, while twelve biopsies showed decreased levels of disaccharidase activities. 2. All biopsies, normal as well as abnormal, showed essentially the same capacity to hydrolyse the sugar alcohols. Activities towards lactitol (0.34 IE/g protein (where IE = mumol disaccharide hydrolysed/min at 37 degrees)) and Palatinit (2.50 IE/g protein) were only 1.3% of those towards lactose and isomaltose. The activity towards maltitol was much higher (19.1 IE/g protein), approximately 10% of that towards maltose and about as high as the activity towards trehalose. This finding indicates that despite the fact that lactitol and Palatinit were poor substrates, significant amounts of ingested maltitol might be digested and utilized by man. 3. Glucose release was reduced by approximately 25% when maltitol or Palatinit were present at concentrations equal to those of maltose. Palatinit decreased the hydrolysis of sucrose by 12%. Lactitol had no inhibitory effect on the hydrolysis of disaccharides.

Adolescent↗

PubMed1986

Pre-operative infusion cholangiography compared to routine operative cholangiography at elective cholecystectomy.

Routine operative cholangiography (group 1) was compared with pre-operative intravenous infusion cholangiography and selective operative cholangiography (group 2) in 200 patients subjected to elective cholecystectomy. All patients were examined with pre-operative intravenous infusion cholangiography. In group 1 patients, this examination was not made available to the surgeon and not used in any way except for a later analysis. Thirteen patients had to be excluded for different reasons. In group 1, normal operative cholangiograms were obtained in 82/94 cases. Choledocholithotomy was performed in 7/12 cases, choledochotomy in 2/12 and no exploration in 3/12 cases. In group 2, pathological or inconclusive infusion cholangiograms were demonstrated in 17/91 cases. Choledocholithotomy was performed in 11/17 cases. One of 17 patients was subjected to choledochotomy only. In 5/17 patients, no exploration was carried out because of normal operative cholangiography. No residual or retained stone/s have been revealed during a follow-up period of 1 year. The general clinical outcome in the two groups of patients was similar. Significantly shorter operative time was an important advantage of the strategy in group 2 patients.

Adolescent↗

PubMed1986

Polymorphonuclear neutrophil function and infections following splenectomy in childhood.

22 subjects were controlled 3-23 yr after splenectomy due to childhood trauma (10), idiopathic thrombocytopenic purpura (9) or congenital spherocytosis (3). The control comprised a history of infections, physical examination, routine hematologic values, determinations of serum immunoglobulins, evaluation of complement activities, cultivations from throat and nasopharynx and polymorphonuclear neutrophil (PMN) function tests. 14 patients (63%) had increased susceptibility to recurrent bacterial infections (SBI), most often tonsillitis. All these patients also had abnormal PMN function. The other 8 patients with normal susceptibility to infections showed essentially normal PMN function. There were no differences between these groups with regard to indication for splenectomy, age at splenectomy or the time interval after splenectomy. This abnormal PMN function may explain the raised susceptibility to infections.

Adolescent↗

PubMed1986

Serum immunocomplexes in patients with subarachnoid hemorrhage.

Immunocomplexes (IC) in serum were analyzed in 54 patients with subarachnoid hemorrhage (SAH) from ruptured arterial aneurysms. A previous study had shown that patients with SAH and vasospasm had a significantly higher incidence of ICs in the blood than patients without vasospasm. The aim of the present study was to study how the IC content varied with time and compare this pattern with the clinical picture. Forty-two patients presented clinical or radiological signs of cerebral vasospasm during their hospital stays, whereas 12 patients showed no such signs. The patients with vasospasm had a significantly higher amount of ICs in serum than those without vasospasm. In 37 patients with vasospasm, the changes of IC content during the 1st weeks after SAH correlated well with the clinical course. Data indicated that a high IC content preceded the onset of vasospasm and a low content preceded clinical improvement. This observation supports the idea that the presence of ICs might be the cause and not the result of vasospasm.

Adult↗

PubMed1986