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Biomedical subjects

J Bergström

Publications and source records attributed to J Bergström.

At least 145 records · Page 8Linked to original sources
PubMed1994

Glycoproteins with Gal alpha 4Gal are absent from human erythrocyte membranes, indicating that glycolipids are the sole carriers of blood group P activities.

The antigenic determinants of the blood group P family (P1, P, Pk, and LKE antigens) are chemically based on Gal alpha 4Gal. For human erythrocytes it has been claimed that the majority of P1 determinants are expressed in glycoproteins, mainly band 4.5 (Haselberger, C. G., and Schenkel-Brunner, H. (1982) FEBS Lett. 149, 126-128). In the present work, the existence of Gal alpha 4Gal in glycoproteins of erythrocyte membranes (ghosts) of P1 positive and negative human individuals was carefully analyzed on replicas of sodium dodecyl sulfate-polyacrylamide electrophoresis gels using specific reagents (Escherichia coli HB101/pDC1 expressing the Pap gene and monoclonal antibodies with specificities for P1 and Pk antigens). No binding to glycoproteins was detected with any of these ligands when the ghosts had been pretreated with butanol to remove glycolipids. Therefore, all antigenic determinants of the P blood group family on human red cells are exclusively expressed in glycolipids and are absent from glycoproteins.

Antibodies, Monoclonal↗
PubMed1994

Binding of the galactose-specific Pseudomonas aeruginosa lectin, PA-I, to glycosphingolipids and other glycoconjugates.

The carbohydrate-binding specificity of Pseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal alpha 3Gal- or Gal alpha 4Gal-structures.

Adhesins, Bacterial↗
PubMed1994

Hemodialysis-associated protein catabolism with and without glucose in the dialysis fluid.

The effects of hemodialysis on protein and energy metabolism were studied in eight hemodialysis patients. The leg exchange of amino acids (AA) was measured during hemodialysis using a dialysis fluid with 10 mmol/liter glucose (GD) or without glucose (GFD). Arterial AA concentrations decreased by about 30% in GD and GFD. During dialysis, similar increases in the efflux of AA from leg tissues (mainly muscle) were observed in GD and GFD (basal 105 +/- 104, vs. 71 +/- 62 nmol/min/100 g tissue; dialysis 295 +/- 46 vs. 289 +/- 60 nmol/min/100 g tissue). The efflux of AA remained largely unchanged at one hour after the end of GD and GFD. Losses of AA to the dialysate were similar during GD (8.3 +/- 0.9 g) and GFD (7.9 +/- 0.4; NS). GFD resulted in a loss of 26 g of glucose whereas 30 of glucose was absorbed during GD. The amount of urea removed by dialysis and the post-dialysis increase in plasma urea were similar in GD and GFD. In conclusion, the addition of glucose to the dialysis fluid may help the energy balance, but it does not appear to reduce the negative effects of hemodialysis on protein metabolism.

Aged↗
PubMed1994

Biocompatibility of hemodialysis membranes: a study in healthy subjects.

The effect of blood-membrane interaction on several biocompatibility parameters has been investigated. Four groups of healthy subjects underwent sham hemodialysis, i.e. the establishment of blood-dialysis membrane contact, but without circulating dialysate, using cellulose-based membranes (regenerated cellulose and cellulose acetate) or synthetic membranes (polysulfone and polyacrilonitrile). Contact between blood and cellulose-based membranes resulted in pronounced complement activation and leukopenia whereas contact between blood and synthetic membranes induced weak complement reaction. The release of granulocytic elastase comparable to that obtained during clinical dialysis seemed to correlate directly with the types of membrane used. The gradual increase in the level of plasma elastase during blood-membrane contact, as opposed to the transient nature of the increase in the levels of complement, suggests that different mechanisms are responsible for these reactions. Nutritional implications of dialysis membrane bioincompatibility are discussed in the light of recently published metabolic data obtained in these subjects.

Acrylic Resins↗
PubMed1994

Tobacco use as a risk factor.

Tobacco, particularly tobacco smoking, has a substantial influence on periodontal health and disease. It is associated with an increased disease rate in terms of periodontal bone loss, periodontal attachment loss, as well as periodontal pocket formation. In addition, it exerts a masking effect on gingival symptoms of inflammation. Risk assessment based on an increasing body of investigations over the past few years suggests that the tobacco attributable risk is considerable, estimated odds ratios being of the order 2.5 to 6.0 or even greater. Although the mechanisms by which tobacco exerts its influence are obscure, information available to date does not support the view that its action simply relates to other environmental factors such as the dental plaque or some specific microflora. It seems more likely that it primarily has a systemic influence affecting host response or susceptibility. The chief novelty of the present report is that current data suggest that, although the overall disease prevalence is decreasing, the proportion of periodontal disease attributed to tobacco is stable or even increasing. This seems to be analogous to what has been observed for other smoking-associated chronic diseases. This, in turn, indicates that periodontal disease behaves like several other chronic diseases and, further, that tobacco should be considered a major risk factor for chronic periodontal disease.

Adult↗
PubMed1994

Tryptophan and its metabolites in patients on continuous ambulatory peritoneal dialysis and following renal transplantation.

Plasma tryptophan (Trp) concentration in its total (TTrp) and non-protein-bound free form (FTrp) and its metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) as well as muscle Trp contents (MTrp) were studied in 12 uraemic patients undergoing continuous ambulatory peritoneal dialysis (CAPD), 10 renal transplant patients, and 10 healthy control subjects. The CAPD patients exhibited signs of muscle weakness, as assessed by dynamometry, and signs of protein malnutrition with a decreased ratio of alkali-soluble protein relative to DNA in muscle as well as low serum albumin concentration. In the uraemic patients TTrp was markedly reduced, whereas in the transplant patients it did not differ from the controls. The FTrp, which was separated by the process of equilibrium dialysis, was less in the uraemic (P < 0.01) as well as transplant patients (P < 0.01) than in the controls. The plasma FTrp/TTrp ratio was increased in the uraemic patients (40 +/- 8%) but less in the transplant patients (16 +/- 4%), as compared to the controls (25 +/- 5%). The uraemic patients had increased plasma concentrations of 5-HIAA, whereas this metabolite could not be found in the plasma of renal transplant patients and healthy controls. MTrp was increased by an average of 33% in the uraemic patients whereas it did not differ between the transplant patients and the controls. The results indicate that the abnormal Trp metabolism in uraemic patients is to a large extent corrected by a successful renal transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Muscle and plasma amino acids and nutritional status in kidney-transplanted children.

Nutritional status, assessed by anthropometric and biochemical methods, protein and amino-acid (AA) composition and muscle water were evaluated in 11 kidney transplanted children and in a control group of 10 children with normal renal function who were undergoing elective surgery. Samples of the rectus abdominis muscle were taken when surgery was performed in the control children and when the peritoneal catheter was removed in the transplanted children. The mean time from the transplantation to the study time was 97 +/- 14 days (range 72-114 days). Height was reduced in the transplanted children compared to the controls but skinfold thickness, arm muscle circumference and serum proteins (total protein, albumin, transferrin, pseudocholinesterase) were normal. The body mass index was over the 50 degree percentile in nine of the eleven children. The muscle contents of total, extracellular, and intracellular water, alkali-soluble protein (ASP), DNA and the ASP/DNA ratio were not significantly different in transplanted children from those in the controls. Plasma leucine and taurine levels were significantly decreased, whereas plasma citrulline and alanine levels and the glycine/serine ratio were increased. Muscle threonine, alanine+taurine, glycine and aspartic acid levels as well as the glycine/serine ratio were increased in the transplanted children. Transplanted children show an almost normal muscle AA profile and a plasma AA pattern that seems to be related to the prednisone therapy.

Adolescent↗
PubMed1994

Nutritional status, muscle composition and plasma and muscle free amino acids in renal transplant patients.

To investigate the effects of renal transplantation (Rtx) on the nutritional status, muscle composition and the plasma and muscle free amino acid (AA) pattern, three groups of altogether 30 renal transplant patients (group I n = 10; 46 +/- 14 [SD] days after Trx), (group II n = 10; 13 +/- 2 months after Rtx) and (group III n = 10; 9 +/- 2 years after Rtx) underwent anthropometric measurements, blood sampling and percutaneous muscle biopsy. The immunosuppressive therapy consisted of prednisolone, azathioprine and cyclosporine-A. The results were compared with data from age-matched healthy subjects. Renal function was impaired in groups I, II and III. Serum albumin was decreased in groups I and II. The patients of group II had an increased percentage of body fat, triceps and subscapular skin folds and total sum of skinfolds. In group I the ratio alkaline-soluble protein (ASP) to DNA, which is a sensitive index of protein depletion on the cellular level, was decreased. Muscle magnesium content was decreased whereas the muscle DNA, sodium and chloride contents were increased. The mean plasma concentration of most essential AA (EAA) was essentially normal except phenylalanine which was increased in groups I and II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Albumin and amino acid levels as markers of adequacy in continuous ambulatory peritoneal dialysis.

Similar to previous findings in HD patients, a markedly decreased serum albumin level has been found to be a strong predictor of morbidity and mortality in CAPD patients. However, a slight decrease in serum albumin levels (to about 30 g/L if measured with nephelometry or the bromcresol purple method) does not always seem to reflect impaired nutritional status or to be associated with an increased morbidity or mortality in CAPD patients. A low serum albumin level among CAPD patients is related to dialysate albumin loss, comorbidity, age, and a low dietary protein intake. The possible relation between the dialysis dose (as assessed by small solute clearances) and serum albumin levels among CAPD patients is much less established and needs further study, although serum albumin tends to increase in prospective studies of increased peritoneal dialysis dose. Although the plasma levels of amino acids seem to be lower in CAPD patients compared to HD patients, this does not reflect the intracellular amino acid pattern in muscle which is less abnormal in CAPD patients, possibly because of the sustained hyperinsulinemia during CAPD, resulting in an increased intracellular to extracellular gradient. It is at present not established to what extent the amino acid abnormalities are related to the dialysis dose. Malnourished and hypoalbuminemic CAPD patients should be recommended to increase the protein intake, and if this is not effective, the dialysis dose should be increased. Furthermore, the use of amino acid-based peritoneal dialysis solutions is a promising new tool for the treatment of malnourished CAPD patients and may become an important component of CAPD therapy in the future. On the other hand, if the nutritional status deteriorates in spite of these efforts, the patient should be transferred to hemodialysis if possible.

Amino Acids↗
PubMed1994

Treatment of IgA nephropathy with omega-3-polyunsaturated fatty acids: a prospective, double-blind, randomized study.

In several studies diets supplemented with fish oil containing a high proportion of omega-3-polyunsaturated fatty acids (w-3-PUFA) have been shown to produce beneficial effects, such as a reduction in blood pressure, lipid levels and inflammation, all of which may affect the course of IgA nephropathy. However, the results of hitherto published studies concerning IgA nephropathy have been inconclusive. We therefore carried out a prospective, randomized, placebo-controlled six-month study with a higher daily dose of w-3-PUFA than used in previous studies. Thirty-two adult patients with biopsy-proven IgA nephropathy and proteinuria completed the study: 15 were assigned to a fish-oil product with a high percentage of w-3-PUFA (K 85, with 55% eicosapentenoic and 30% docosahexenoic acid) and 17 to corn oil, 6g daily of either oil. At the start, no significant differences were found between the two groups (K85: 3 females/12 males, mean age 39 years (range 22-64), corn oil: 4 females/13 males, age 42 years (range 26-68). By six months, supplements of K85 resulted in a slight but significant reduction in glomerular filtration rate (GFR) compared to the start: 51Cr-EDTA: 63 +/- 22 to 59 +/- 21 ml/min/1.73 m2 (p < 0.05), creatinine clearance: 91 +/- 31 to 79 +/- 25 ml/min (p < 0.01), s-creatinine: 131 +/- 39 to 139 +/- 39 mumol/l, whereas no change in GFR was observed in the corn oil group. The urinary total protein and red blood cell excretions were not affected in any of the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1994

Effect of low level energy laser irradiation on gingival inflammation.

The effect of low level energy infra-red laser irradiation on gingival inflammation was studied. Gingivitis was induced in ten female dental students by refraining from all oral hygiene measures for 28 days. On days 21 and 24 the marginal gingiva, buccal to one of the lateral mandibular incisors, was exposed to 4 minutes of laser irradiation (total dose = 1J). Serving as a control site the gingiva of the contralateral incisors was exposed to ordinary light. There was no statistical difference between the laser exposed sites and the control sites related to either plaque formation or gingival bleeding. The gingivitis reaction was evaluated with the aid of a stereophotographic method by calculating changes in the number of gingival vessels. It was found that the number of vessels identified increased over time for both laser exposed and control sites. The difference between sites at day 28 was not statistically significant (t = 0.82, P > 0.05). These results suggest that low energy laser irradiation (LLLT) does not influence the inflammatory reaction of the gingiva.

Adult↗
PubMed1994

Membrane biocompatibility and nutrition in maintenance haemodialysis patients.

The interrelationship between Kt/V (urea), protein catabolic rate, dialysis membrane, nutritional status and outcome: These correlations are summarized in Figure 3. A given dialysis membrane will allow a given Kt/V (urea) and hence, influence urea removal. The balance between urea removal and urea generation will determine the urea pool and the urea concentration for a given volume of distribution. It is postulated that this urea concentration in some way causes 'biofeedback' determining the protein intake of a given patient which, of course, will influence the protein catabolic rate and hence, the urea generation. The protein catabolic rate may be adversely influenced by the use of bioincompatible membranes which produce activated complement, IL-1, tissue necrosing factor, etc. In addition, the membrane will determine the Kt/V (other toxins; 'middle molecules') which may also influence protein intake. The protein intake will affect the overall nutritional status which, in turn, has a major impact on morbidity and mortality. We suggest that the most effective way to influence morbidity and mortality is to ensure that a Kt/V (urea) well in excess of 1 (perhaps between 1.4 and 1.6) is delivered to the patient if a cellulosic membrane is used. It may be possible to deliver less than this value using a biocompatible membrane which has increased Kt/V (middle molecules) for a given Kt/V (urea). Whatever the method of dialysis or Kt/V (urea) applied, attention should also be gi en to nutritional assessment of the patient, and amongst the tools available to the clinician is the estimation of the protein catabolic rate by urea kinetic modelling.(ABSTRACT TRUNCATED AT 250 WORDS)

Biocompatible Materials↗
PubMed1994

Evaluation of an experimental rat model for peritoneal dialysis: fluid and solute transport characteristics.

The aim of this study was to develop a reference model of fluid and solute transport during experimental peritoneal dialysis in rats, which would simulate the conditions of clinical dialysis in CAPD patients as much as possible. For this purpose a 4-h dialysis study was performed in 13 normal Sprague-Dawley rats with conventional glucose solutions (Dianeal 1.36% solution, n = 6 and Dianeal 3.86% solution, n = 7) and a protocol and methods like those used in clinical dwell studies. The dilution of a marker, radioactive human serum albumin (RISA), was used to determine the intraperitoneal dialysate volume with corrections for the elimination of RISA from the peritoneal cavity and sample volumes. The isovolumetric method was employed to calculate the diffusive mass transport coefficients. To compare our data with reference values in CAPD patients, the data were scaled by a factor calculated as a ratio of the dialysate volume in CAPD to the dialysate volume in the rats. In a separate series of experiments the intraperitoneal hydrostatic pressure was monitored with increasing infusion volumes. The fluid transport characteristics, described as the percentage changes of the initial intraperitoneal volume, were essentially comparable to those in CAPD patients. However, the intraperitoneal volume curves were shifted more to the left than were the reported values in CAPD patients. The scaled diffusive mass transport coefficient for urea was similar to that in CAPD patients. However, the transport of other solutes, in particular glucose, was faster in the rats than in CAPD patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The diurnal variation of urea in cow's milk and how milk fat content, storage and preservation affects analysis by a flow injection technique.

Six Swedish Red and White dairy cows, producing 20-39 kg of 4% fat-corrected milk were given a ration balanced in energy and protein. They had access to feed from 05.15 to 09.00 and from 13.00 to 16.30 and were milked at 06.15 and 15.30. The milk was analysed for urea with a FIA technique. There was a significant diurnal variation in milk urea. The highest values were found 3-5 h after the beginning of the morning feeding and the lowest values (down to 60% of the max. values) during late night. Within 1 h after the start of the morning feeding the urea values had increased significantly, but they had decreased within the same time after the start of the afternoon feeding. Since there was a pronounced diurnal variation in the milk fat content, the urea concentration was also recalculated to concentration in the water phase of the milk. It was higher in that phase, but the pattern of the diurnal variation was not changed significantly. However, analyses on milk with a very high fat content may give misleading results. There were no important differences in the milk urea concentration of different udder quarters. When calculated as concentration in the water phase of the milk, no differences in urea concentration were found between the beginning and the end of milking. The analytical method had a good precision (coefficient of variation max. 3%). The milk urea concentration was not changed significantly after storage during 10 days at 4 degrees C when no preservative was added; but after 17 days the milk had turned sour and the urea value had increased. When a preservative (bronopole) was added the urea concentration remained unchanged during 17 days. Deepfreezing did not influence the urea concentration.

Animals↗
PubMed1993

Protein and energy intake, nitrogen balance and nitrogen losses in patients treated with continuous ambulatory peritoneal dialysis.

The aim of this investigation was to analyze factors which influence the dietary protein intake (DPI), the energy intake and the utilization of ingested protein, and to determine the relationship between various types of nitrogen losses in stable continuous ambulatory peritoneal dialysis (CAPD) patients. We performed 23 nitrogen balance (NB) studies of 6 to 11 days duration in 12 CAPD patients. One study was performed in all patients 3.4 +/- 1.2 months after starting CAPD (early studies). The study was then repeated in nine patients after 12.1 +/- 2.6 months, and two of these patients were studied again after 16 and 24 months, respectively (late studies). Before each NB study, the dietary intakes prior to the study were assessed in diaries and interviews. During a few days preceding the NB periods and during the NB periods each patient received an individualized diet composed so as to resemble the patients' spontaneously chosen diet regarding DPI and dietary energy intake (DEI). Total nitrogen, protein, urea and creatinine were analyzed in the dialysate and urine collected daily. Total nitrogen was also analyzed in the feces, collected over the whole NB period. Total nitrogen appearance (TNA), non-protein nitrogen appearance (NPNA) and urea nitrogen appearance (UNA) were calculated by correcting total nitrogen output, non-protein nitrogen output, that is, TNA minus the total protein losses (PL) and urea nitrogen output for changes in total body urea nitrogen. Glucose was determined in the collected dialysate and the daily glucose absorption was calculated. DPI varied between 0.62 and 2.09 g/kg/day, DEI between 21 and 42 kcal/kg/day and the peritoneal energy (glucose) intake (PEI) between 4 and 13 kcal/kg/day. DPI (but not DEI) correlated with Kt/V(urea) and Kt/VCr and with total and renal clearances for urea and creatinine. NB (not corrected for "unmeasured" nitrogen losses) was positive in most studies, and it correlated with DPI and the total energy intake (TEI) in the early studies, but only with TEI in the late studies. DPI correlated with TNA, NPNA, UNA, non-protein-non-urea nitrogen loss and fecal nitrogen loss. UNA was highly correlated with TNA and NPNA (r = 0.95). We used data from 33 NB studies in CAPD patients (our present data combined with data from the literature) to calculate regression equations describing the relationship between TNA and NPNA, respectively, and UNA.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1993

Treatment of anaemia in haemodialysis patients with erythropoietin: long-term effects on exercise capacity.

1. The effects of correcting anaemia on exercise capacity were evaluated in 21 haemodialysis patients (aged 39 +/- 12 years) before starting treatment with recombinant human erythropoietin (Hb concentration, 73 +/- 10 g/l; total Hb, 59 +/- 12% of expected), after correction of the anaemia to a Hb concentration of 108 +/- 7 g/l and a total Hb 82 +/- 10% of expected, and in 13 of the patients after 12 months on maintenance recombinant human erythropoietin treatment (Hb concentration 104 +/- 14 g/l, total Hb 79 +/- 17% of expected). Fifteen healthy subjects (aged 41 +/- 9 years), who took no regular exercise, constituted the control group. Maximal exercise capacity was determined on a bicycle ergometer. Oxygen uptake, respiratory quotient, blood lactate concentration, heart rate and blood pressure were measured at rest and at maximal workload. 2. After 6 +/- 3 months on recombinant human erythropoietin, maximal exercise capacity increased from 108 +/- 27 W to 130 +/- 36W (P < 0.001) and the maximal oxygen uptake increased from 1.24 +/- 0.39 litres/min to 1.50 +/- 0.45 litres/min (P < 0.001). No significant changes in respiratory quotient (1.16 +/- 0.13 versus 1.18 +/- 0.13) and blood lactate concentration (4.0 +/- 1.8 versus 3.6 +/- 1.1 mmol/l) at maximal workload were observed, but the blood lactate concentration in the patients was significantly lower than that in the control subjects (6.7 +/- 2.3 mmol/l, P < 0.01). After the correction of anaemia, the aerobic power was still 38% lower in the patients than in the control subjects and 17% lower than the reference values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗