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Biomedical subjects

J Bergström

Publications and source records attributed to J Bergström.

At least 127 records · Page 7Linked to original sources
PubMed1996

Evidence of taurine depletion and accumulation of cysteinesulfinic acid in chronic dialysis patients.

Methionine, taurine and cysteinesulfinic acid (CSA) were determined by reversed-phase high-performance liquid chromatography (RP-HPLC) in plasma from ten patients treated with hemodialysis (HD) and eight patients treated with continuous ambulatory peritoneal dialysis (CAPD). The patients' data were compared with data obtained from ten healthy controls. Significant reductions in plasma taurine levels were observed in the HD patients (34 +/- 13 mumol/liter, mean +/- SD) and the CAPD patients (47 +/- 12 mumol/liter) compared to the controls (66 +/- 5 mumol/liter), while the CSA levels were markedly higher in the HD patients (9.1 +/- 2.8 mumol/liter) and the CAPD patients (9.1 +/- 2.4 mumol/liter) than in the controls (0.79 +/- 0.15 mumol/liter). A single HD treatment significantly reduced the plasma taurine and CSA concentrations (P < 0.01 and P < 0.001), respectively. The plasma methionine levels were normal in both patient groups. The finding of a low plasma taurine level and a large accumulation of CSA suggests that the metabolic conversion of CSA to taurine is impaired in uremic patients and this metabolic abnormality may cause taurine depletion.

Adolescent↗
PubMed1996

Multifrequency bioimpedance in assessment of dry weight in haemodialysis.

The use of multifrequency bioimpedance (MFB) for determination of dry weight (DW) in haemodialysis (HD) patients was evaluated in three studies. In Study 1, the fluid state [total body water (TBW) and extracellular volume (ECV)] was measured by MFB in 82 normotensive patients. 41 hypertensive patients and in 30 healthy subjects. TBW and ECV were expressed as per cent of body weight (BW). In Study 2, DW of five hypertensive HD patients was gradually decreased during 3 months and ECV (MFB) and blood pressure (48 h ambulatory blood pressure monitoring) were measured at the beginning and end of study. In Study 3, we measured the fluid status repeatedly by MFB and the diameter of the inferior vena cava (DIVC) by ultrasound before, during and 2 h post-HD. In Study 1, the hypertensive patients had significantly greater TBW (P < 0.05) than the normotensive patients before (50.3 +/- 6.5% vs 47.6 +/- 5.8%) and after HD (48.8 +/- 7.8% vs 45.7 +/- 6.4%) and ECV (P < 0.001) before (29.4 +/- 3.6% vs 26.8 +/- 3.5%) and after HD (27.0 +/- 4.0% vs 24.6 +/- 3.5%), Post-HD ECV in the normotensive patients was similar to that in the healthy subjects. In Study 2, more efficient ultrafiltration resulted in reduction of BW and ECV along with a decrease in blood pressure and need for antihypertensive medication. In Study 3, both ECV and DIVC decreased following the removal of fluid during HD. ECV maintained stable values during the post-HD period, unlike DIVC which increased significantly (P < 0.005) due to refilling from the interstitial space. We conclude that MFB is an appropriate non-invasive method for DW determination, which is highly reproducible and technically simple to use.

Adult↗
PubMed1996

Middle-sized molecule fractions isolated from uremic ultrafiltrate and normal urine inhibit ingestive behavior in the rat.

Uremic patients with suppressed food intake may regain appetite soon after starting dialysis, presumably because of the removal of one or more toxic factors that suppress appetite. To investigate this matter, this study used a new experimental model in free-moving, unstressed male Wistar rats (300 to 350 g) with feeding catheters channeled from the top of the skull to the oral cavity. When the rats recovered from surgery, they were tested under standardized conditions by being given an intraoral infusion (1 mL/min) of a 1 M sucrose solution or a 97 g/L protein solution or a mixed solution of carbohydrate, protein, and fat (Fortimel (Nutricia Nordica AB, Stockholm, Sweden)) while the time (volume) of ingestion was recorded. Solutions to be tested for their ability to inhibit ingestion were injected intraperitoneally (lp) and the intraoral infusion was started 20 min later. Plasma ultrafiltrate was collected from end-stage renal failure patients by isolated ultrafiltration at the beginning of their first hemodialysis and pooled. Ultrafiltrate was also obtained by filtering pooled plasma from healthy volunteers in vitro, using the same type of dialyzer and cellulose acetate membranes as those used in the uremic patients. Morning urine samples from healthy volunteers were pooled and subjected to the same in vitro filtration procedure as the normal plasma. Intraperitoneal injection of 20 mL normal ultrafiltrate had no effect on sucrose ingestion, whereas injection of 20 mL uremic ultrafiltrate reduced the ingestion of sucrose solution by 23% and the ingestion of Fortimel by 17%. Ten mL of ultrafiltrate from normal urine reduced the sucrose intake by 42%. The pooled ultrafiltrates from normal and uremic plasma and normal urine were subjected to molecular filtrations using a series of membranes with known cut-off points. The filtrations yielded four concentrated fractions with molecular weight ranges of 0.1 to 0.5 kilodaltons (kd), 0.5 to 1 kd, 1 to 5 kd, and 5 to 10 kd, respectively; the plasma fractions were concentrated a factor of about 25:1 and the urine fractions by about 15:1. After an ip injection of 2 mL of each concentrated plasma fraction, only the 1 to 5 kd fraction from the uremic ultrafiltrate inhibited sucrose intake, whereas the corresponding fraction from the normal ultrafiltrate had no effect. After injection of 1, 3, and 5 mL of the concentrated fractions of uremic ultrafiltrate, a dose-dependent inhibition of sucrose intake was achieved with the 1 to 5 kd fraction and, to a lesser extent, with the 5 to 10 kd fraction. Intraperitoneal injection of 0.5, 1.0, and 2 mL of the concentrated 1 to 5 kd fraction, but not of the other fractions from normal urine, also resulted in a dose-dependent inhibition of sucrose intake. The 1 to 5 kd fractions from the uremic ultrafiltrate and the normal urine ultrafiltrate also inhibited protein intake in a dose-dependent manner. These results suggest that one or more toxic compounds in the middle-molecule weight range, which are normally excreted in the urine, accumulate in uremia and suppress food intake.

Animals↗
PubMed1996

Anorexia in dialysis patients.

Malnutrition, which is common in maintenance dialysis patients, is strongly associated with increased morbidity and mortality. An important contributing factor is anorexia, leading to reduced intake in relation to the recommended allowances, which for protein is higher than in healthy subjects. Uremic toxicity in underdialyzed patients may cause anorexia as a result of retention of toxic compounds in the middle molecular weight range, which are normally excreted in the urine. Various comorbidity factors and psychosocial and economic factors may also be associated with low nutritional intake. The hemodialysis procedure may reduce nutritional intake because of cardiovascular instability with nausea and vomiting and post-dialysis fatigue. Abdominal discomfort, absorption of glucose and amino acids, and peritonitis may reduce appetite in peritoneal dialysis patients. Underdialysis, if present, should be corrected and various catabolic factors such as acidosis, infections, and other comorbidity factors should be treated, dietary counseling should be given, and psychosocial and economic support should be provided when needed. Patients who remain malnourished despite such measures may be given parenteral or enteral nutritional supplementation. Peritoneal dialysis solutions with amino acids have been used successfully in CAPD patients who suffer from protein malnutrition. Recombinant human growth hormone and IGF-1 are new treatment alternatives that need further evaluation.

Anorexia↗
PubMed1996

Children on continuous ambulatorial peritoneal dialysis: muscle and plasma proteins, amino acids and nutritional status.

The aim of the study was to investigate plasma and muscle amino acid (AA) levels in children on continuous ambulatory peritoneal dialysis (CAPD) and their relationship to various indices of nutritional status. Ten children with a mean age of 6.4 +/- 5.6 yrs were evaluated. Muscle biopsies and venous blood samples were taken after an overnight fast. Muscle samples were obtained from rectus abdominis. Data were compared with those of a control group of 22 children who were undergoing elective surgery. Informed consent was obtained from the parents. The plasma concentration of most of the essential AA (valine, leucine, isoleucine, lysine, methionine and tyrosine) were significantly reduced and the levels of some non essential AA (aspartic acid, glycine, citrulline, 1-3 methihystidine, taurine + alanine) were significantly higher than in the controls. Muscle intracellular free essential AA concentrations, except the low levels of valine and leucine did not differ significantly from values in the controls. Among non essential AA, aspartic acid, glutamic acid and ornitine showed significantly increased intracellular concentrations. No significant correlations were found between plasma and muscle AA concentration and ASP (alkali-soluble protein)/DNA ratio, serum albumin, transferrin, bicarbonate levels and duration of CAPD. Instead, a significant correlation was noted between the muscle ASP/DNA ratio, an indicator of the amount of cell proteins per cell unit, and age (r = 0.714, p < 0.05). Muscle Branched chain AA levels were significantly correlated to body mass index (BMI) (r = 0.648, p < 0.05).

Adolescent↗
PubMed1995

The PapG-adhesin at the tip of P-fimbriae provides Escherichia coli with a competitive edge in experimental bladder infections of cynomolgus monkeys.

Human urinary tract infection is an infectious disease that depends on a series of host-microbial interactions. The bacteria first colonize the colon and then the periurethral/vaginal areas; they ascend to and infect first the bladder and then the kidneys. Expression of Escherichia coli P-fimbriae constitutes the strongest correlation to renal pathogenicity, but is also related to first-time cystitis in children. The role of P-fimbriae in the preceding steps in the infectious process is unknown. To examine this, we constructed, from a P-fimbriated E. coli strain with a class II G-adhesin preferentially binding to globoside, one isogenic mutant lacking the G-adhesin and another isogenic mutant in which we replaced the papG class II allele with a class III adhesin preferentially binding to the Forssman antigen. We report here the comparison of the adhesin knockout mutant (DS17-8) and the class-switch mutant (DS17-1) with the wild-type (DS17) for in vivo colonization of the gut, vagina, and bladder of cynomolgus monkeys. It was recently shown that the class II tip G-adhesin is a prerequisite for acute pyelonephritis to occur in the monkey model in the absence of other kidney-specific adhesins or obstruction of the urinary flow. Here we show that it is not required for bladder infection but gives a competitive advantage in mixed infections. In the vagina and colon, the G-adhesin gives no competitive advantage.

Adhesins, Escherichia coli↗
PubMed1995

Glycoconjugate receptors for P-fimbriated Escherichia coli in the mouse. An animal model of urinary tract infection.

Glycosphingolipids were isolated from kidneys, urethers, and bladders (including urethrae) of C3H/HeN mice. Binding was studied of a clinical isolate and recombinant strains of uropathogenic P-fimbriated Escherichia coli to these glycolipids. A series of receptor-active glycolipids with Gal alpha 4Gal in common, previously shown to be recognized by these bacteria, was identified by use of specific monoclonal antibodies, fast-atom bombardment and electron-impact mass spectrometry, and proton nuclear magnetic resonance spectroscopy: galabiosylceramide (Gal alpha 4Gal beta Cer), globotriaosylceramide (Gal alpha 4Gal beta 4Glc beta Cer), globoside (GalNAc beta 3Gal alpha 4Gal beta 4Glc beta Cer), the Forssman glycolipid (GalNAc alpha 3GalNAc beta 3Gal alpha 4Gal beta 4Glc beta Cer), Gal beta 4GlcNAc beta 6(Gal beta 3)GalNAc beta 3Gal alpha 4Gal beta 4Glc beta Cer, and Gal beta 4(Fuc alpha 3)GlcNAc beta 6(Gal beta 3)GalNAc beta 3Gal alpha 4Gal beta 4Glc beta Cer. The binding pattern for mouse kidney glycolipids differed from that for kidney glycolipids of man and monkey. In particular, the dominant 8-sugar glycolipid in the mouse was not detected in the primates. A second difference was found in the binding of E. coli to kidney glycoproteins on blots after electrophoresis; the mouse showed distinct receptor-active bands while human and monkey did not. These differences may be of relevance when using the mouse as a model for clinical urinary tract infection of man.

Animals↗
PubMed1995

A proposed glossary for dialysis kinetics.

Quantification of the dialysis dose and assessment of nutritional status and response to nutritional therapy have become standard parts of the management of the chronic dialysis patient. Although advances in these areas have led to a more rational basis for therapy, certain misconceptions and points of confusion appear to have occurred. Recognizing the importance of a standard nomenclature to the development of concepts and the communication of research findings, we have attempted to compile a list of terms that are commonly used in the field of dialysis. New terms have been proposed for current ones that do not seem adequate. In addition, we have discussed potential methodologies for obtaining more accurate data for dialysis kinetics and for precise monitoring of nutritional intake and status. It is hoped that this glossary will stimulate discussion that will lead to refinements in terminology and concepts that will, in turn, improve research and practice in nephrology. It is anticipated that many of these definitions and recommendations will be modified or superseded as the management of patients with renal failure continues to advance.

Adolescent↗
PubMed1995

Why are dialysis patients malnourished?

There are multiple causes of protein-energy malnutrition in maintenance dialysis patients. The requirements of protein in dialysis patients are higher than in healthy individuals, and the intake of protein and energy in relation to the requirements is frequently low. Anorexia may be caused by uremia and underdialysis. There is experimental evidence that dialyzable uremic toxins accumulate in renal failure and suppress the appetite. In addition there are several psychosocial and comorbidity factors that may hamper adequate nutrition. There are also several factors in dialysis patients that may enhance protein catabolism and increase protein requirements, such as low energy intake, metabolic acidosis, dialytic loss of glucose, protein and amino acids and other catabolic effects of the dialytic procedures, as well as effects of infections and other comorbidity factors. The relative importance of the various factors that cause anorexia and stimulate protein catabolism is still not well understood.

Acidosis↗
PubMed1995

Treatment of malnourished CAPD patients with an amino acid based dialysate.

Nineteen malnourished chronic peritoneal dialysis patients who were ingesting a low protein intake underwent metabolic balance studies to test whether a dialysate that contained amino acids would improve their protein nutrition. Patients lived in the hospital for 35 days while they ate a constant diet and underwent their usual regimen of continuous ambulatory peritoneal dialysis (CAPD). The first 15 days served as a Baseline Phase. For the last 20 days, the usual dialysate was substituted with a dialysate of essentially the same composition except that it contained 1.1% essential and nonessential amino acids and no glucose. Patients received one or two dialysate exchanges with amino acids each day depending on the amount necessary to bring the individual's dietary protein plus dialysate amino acid intake to 1.1 to 1.3 g/kg body weight/day. During Baseline, patients were in neutral nitrogen balance; net protein anabolism was positive, as determined from 15N-glycine studies. After commencing intraperitoneal amino acid therapy, nitrogen balance became significantly positive, there was a significant increase in net protein anabolism, the fasting morning plasma amino acid pattern became more normal, and serum total protein and transferrin concentrations rose. Patients generally tolerated the treatment well, although some patients developed mild metabolic acidemia. These findings indicate that a dialysate containing amino acids may improve protein malnutrition in CAPD patients ingesting low protein intakes.

Acidosis↗
PubMed1995

Albumin-based solutions for peritoneal dialysis: investigations with a rat model.

To evaluate albumin, an osmotic agent for peritoneal dialysis, the peritoneal fluid and solute transport were investigated during a 4-h single cycle peritoneal dialysis with albumin-based dialysis solutions. Two different albumin solutions were used in 15 normal Sprague-Dawley rats: isotonic 7.5% albumin solution (ADS 1, n = 7) and a combined 7.5% albumin and 1.35% glucose solution (ADS 2; n = 8). A standard 1.36% Dianeal solution was used to provide control values (n = 6). The rate of the intraperitoneal volume change (Qv) was positive during the initial 90 min with ADS 2 and during the initial 60 min with Dianeal 1.36% solution but negative with ADS 1. The peritoneal bulk flow reabsorption rate, Qa, was similar in all three groups. The estimated rate of transcapillary ultrafiltration (Qu = Qv + Qa) was positive with all three solutions throughout the dialysis. With ADS 1, Qu increased gradually during the initial 90 min and then remained stable, but it decreased with ADS 2 and Dianeal 1.36% solution. Qu with ADS 2 did not differ from that with Dianeal 1.36% solution during the initial 60 min, but it was significantly higher during the latter part of dialysis. The value of Qu during the last 2 h of dialysis was 0.026 +/- 0.010 and 0.025 +/- 0.009 ml/min with ADS 1 and ADS 2, respectively, and it was significantly higher than that with Dianeal 1.36% solution (0.005 +/- 0.007 ml/min; p < 0.017).(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1995

Periodontal bone loss of teeth with metal posts. A radiographic study.

Periodontal bone loss was compared in teeth with metal posts and contralateral teeth without metal posts by means of intraoral radiographs. 250 subjects with a high standard of dental awareness and a great number of teeth retained were included in the study. The periodontal bone loss was calculated from the ratio of the distance from bone margin to apex (bone height) and the distance from crown tip to apex (tooth length). Intra-individual differences between experimental and control teeth were statistically analyzed with the Student paired t-test. 96 subjects (38%) had > or = 1 teeth with root posts. In all, 172 teeth with posts were found, i.e., on average 1.8 teeth per subject. The means +/- SEM of the ratio bone height to tooth length in experimental and control teeth were 0.52 +/- 0.007 and 0.56 +/- 0.006, respectively. The difference was statistically highly significant (P < 0.001). Statistically significant differences were found for incisors, premolars and molars. Regression analysis indicated more severe bone loss for teeth with longer posts. The results suggest that the periodontal bone support of teeth with metal posts is inferior to that of teeth without metal posts.

Adult↗
PubMed1995

Periodontal healing and periopathogenic microflora in smokers and non-smokers.

The aim of the present study was to monitor the clinical and microbiological effects of non-surgical therapy in smokers and non-smokers. The subject material included 32 patients (age range 32-61 years), 11 men and 21 women with moderate to severe periodontitis. 17 patients were smokers ( > or = 15 cigarettes/day) and 15 non-smokers. All patients were subjected to non-surgical periodontal therapy performed by a dental hygienist. Periodontal variables (plaque index, gingival index and probing depth) were registered and bacterial samples were collected before and 2 months after treatment. The treatment resulted in significant reductions towards very low plaque and gingival indices in smokers and non-smokers alike (p < 0.05). Although probing depth was reduced in both smokers and non-smokers, the probing pocket depth reduction was significantly smaller in smokers than non-smokers (p < 0.05). Microbiologically, the same therapeutical efficacy was attained in both smoking groups, indicating an almost total eradication of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Concerning Prevotella intermedia, out of 14 smokers and 10 non-smokers positive at baseline, 9 and 5, respectively, remained positive after treatment. The results suggest a less favourable clinical outcome of non-surgical therapy in smokers than non-smokers in spite of the fact that the therapy was equally effective with regard to reducing the alleged periopathogens A. actinomycetemcomitans, P. gingivalis and P. intermedia.

Adult↗
PubMed1995

Diet-independent suppression of ingestive behavior by cholecystokinin octapeptide and amino acids.

Male rats consumed much more of an intraorally administered mixed protein, fat and carbohydrate solution than of a carbohydrate solution. Injection of cholecystokinin octapeptide (CCK-8, 0.6-5.0 microgram) suppressed intake of both solutions, but the CCK-A receptor antagonist L-364, 718 (20-40 micrograms) facilitated only carbohydrate intake. Blood levels of CCK-8 were higher after intake of the carbohydrate than the mixed solution. Blood levels of isoleucine, leucine, lysine, threonine, valine, and tryptophan increased only after intake of the mixed solution. Injection of these amino acids suppressed intake of both solutions. Blood levels of amino acids were also less after the seventh than after the first session ingesting the mixed solution. Treatment with CCK-8 or amino acids inhibits intake of any diet, but when secreted endogenously, these signals may terminate the meal in a diet-dependent manner.

Amino Acids↗
PubMed1995

Nutrition and mortality in hemodialysis.

Protein-energy malnutrition is present in a large proportion of maintenance hemodialysis (HD) patients, and it is associated with increased morbidity and mortality. The protein requirements are increased because of the presence of endocrine and metabolic factors related to loss of renal function, the HD procedure, and comorbidity factors, which all stimulate net protein catabolism. The intake protein and energy are frequently reduced because of the underlying disease, psychosocial factors, and uremic anorexia. However, the extent to which underdialysis contributes to anorexia and malnutrition is still not well defined. Malnutrition is generally not recognized as a common direct cause of death as reflected in health statistics, except in the highest age groups. Anthropometric and biochemical signs of malnutrition are associated with increased mortality. A low serum albumin level is a strong predictive risk factor that may reflect not only or mainly protein malnutrition but also the influence of several other morbidity factors (overhydration, infection, chronic disease and others) that may entail an increased risk of death. Low levels of serum creatinine (low muscle mass), serum cholesterol (energy depletion), and BUN and low urea appearance rate (low protein intake) are also correlated to increased mortality. For the prevention and treatment of HD-associated malnutrition, measures should be taken to correct factors that may suppress appetite and increase net protein catabolism (underdialysis, acidosis, low energy intake, comorbid conditions, psychosocial and economic factors). Dietary advice should be given with the aim of ensuring an adequate intake of protein- and energy-giving products. Intradialytic parenteral nutrition may have positive effects on nutritional status when other measures fail. However, the indications for such treatment have not yet been well defined, and the effects on survival, morbidity, and quality of life are not sufficiently well proved. More and better data, generated in prospective, well-controlled studies, are obviously needed before intradialytic parenteral nutrition can be generally recommended as therapy for malnourished HD patients.

Humans↗
PubMed1995

Variations with breed, age, season, yield, stage of lactation and herd in the concentration of urea in bulk milk and individual cow's milk.

The concentration of urea in the milk of 510 dairy cows in 10 herds was determined at regular intervals for a year. The herds contained approximately equal numbers of Swedish Red and White, and Swedish Holstein cows. The mean +/- sd concentration in the samples from individual cows was 5.32 +/- 1.13 mmol/l, and the mean concentration in bulk milk was 5.39 +/- 0.96 mmol/l. These values indicated that on average the herds were fed too much protein relative to their intake of energy throughout the year. Herd factors had a strong influence on the milk urea concentration. The concentration was lower during the first month of lactation than later in the lactation, and lower when the cows were housed during the winter than when they were grazing. There was a weak positive relationship between the daily milk yield and urea concentration, particularly during late lactation, but there was no relationship with either breed or age. Bulk milk urea was a reliable guide to the average urea concentration of a herd.

Age Factors↗