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Biomedical subjects

J Bergström

Publications and source records attributed to J Bergström.

At least 217 records · Page 12Linked to original sources
PubMed1989

Identification and determination of phenylacetylglutamine, a major nitrogenous metabolite in plasma of uremic patients.

Phenylacetylglutamine, a constituent of normal urine, was identified and quantitated in plasma ultrafiltrates from uremic patients. Its concentration ranged from 18 to 366 mumol/l, which shows a greater individual variation than those for the concentrations of urea and creatinine. The plasma level was reduced by hemodialysis. In ultrafiltrates from healthy subjects phenylacetylglutamine could not be detected with the methods used. Thus, it is a major nitrogenous metabolite that accumulates in uremia. A reverse phase HPLC method for the quantitative determination of phenylacetylglutamine in plasma ultrafiltrates is described.

Chromatography, High Pressure Liquid↗
PubMed1988

The vanadium- and molybdenum-containing nitrogenases of Azotobacter chroococcum. Comparison of mid-point potentials and kinetics of reduction by sodium dithionite of the iron proteins with bound magnesium adenosine 5'-diphosphate.

The mid-point potentials of the Fe protein components (Ac2 and Ac2* respectively) of the Mo nitrogenase and V nitrogenase from Azotobacter chroococcum were determined in the presence of MgADP to be -450 mV (NHE) [Ac2(MgADP)2-Ac2*ox.(MgADP)2 couple] and -463 mV (NHE) [Ac2* (MgADP)2-Ac2*ox.(ADP)2 couple] at 23 degrees C at pH 7.2. These values are consistent with a flavodoxin characterized by Deistung & Thorneley [(1986) Biochem. J. 239, 69-75] with Em = -522 mV (NHE) being an effective electron donor to both the Mo nitrogenase and the V nitrogenase in vivo. Ac2*ox.(MgADP)2 and Ac2*ox.(MgADP)2 were reduced by SO2.- (formed by the predissociation of dithionite ion, S2O4(2-)) at similar rates, k = 4.7 X 10(6) +/- 0.5 X 10(6) M-1.s-1 and 3.2 X 10(6) +/- 0.2 X 10(6) M-1.s-1 respectively, indicating structural homology at the electron-transfer site associated with the [4Fe-4S] centre in these proteins.

Adenosine Diphosphate↗
PubMed1988

Reduction of blood pressure retards the progression of chronic renal failure in man.

The effect of blood pressure reduction on the progression rate of chronic renal failure (CRF) was studied in 28 patients with CRF of diverse aetiology entering a prospective study (observation time 7-24 months, mean 16 months). Endogenous creatinine clearance was 12-66 ml/min (mean 30 +/- 3 ml/min). We aimed to keep the blood pressure below 160/90 mmHg. Dietary protein was not restricted. The progression rate of CRF was assessed from the regression coefficients of the regressions of creatinine clearance and the inverse of s-creatinine, respectively, on time. Progression rate and the means of all recordings of mean arterial blood pressure (MAP) and urinary protein excretion, respectively, in each patient during the prospective phase were compared with retrospective data from the proceeding period (observation time 4-25 months, mean 19 months). The patients received various combinations of antihypertensive drugs including diuretics, beta-blockers and vasodilatory drugs. In 19 patients MAP decreased from 109 +/- 2 to 102 +/- 2 mmHg (group I), whereas MAP increased from 105 +/- 2 to 108 +/- 2 mmHg in nine patients (group II). In group I proteinuria was significantly lower (P less than 0.05) and the progression of CRF was approximately 50% slower (P less than 0.01) in the prospective phase than in the retrospective phase; no changes were observed in group II. Calculated for all patients, significant correlations were observed between the change in MAP and the change in progression rate and protein excretion, respectively. These results indicate that lowering of blood pressure results in decreased proteinuria and retardation of the progression of CRF irrespective of the aetiology.

Adult↗
PubMed1988

Influence of cigarette smoking on vascular reaction during experimental gingivitis.

The influence of cigarette smoking on the vascular reaction during plaque induced gingivitis was studied in humans for 28 days. Sixteen healthy dental students, 8 smokers and 8 non-smokers, aged 19-42 yr, volunteered for the experiment. A numerical method was used for the evaluation of the vascular reaction. With the aid of stereophotographs changes in the number of gingival vessels were followed during the experiment. It was found that the number of vessels identified increased over time during the experiment in both smokers and non-smokers. However, in spite of the fact that the plaque accumulation rate was equal, the vascular reaction was less pronounced in smokers. At the end of the experiment after 28 days the intensity of the vascular reaction in smokers was only 50% of that observed in non-smokers. The difference was statistically significant at the P-level of 0.05. One week after termination of the experiment and reinstitution of oral hygiene the number of gingival vessels equaled the pre-experimental values in both groups. The results indicate that the vascular reaction associated with plaque induced gingivitis is suppressed in smokers.

Adult↗
PubMed1988

Cervical abrasion in relation to toothbrushing and periodontal health.

Cervical abrasion and some factors related to oral hygiene habits and periodontal health were investigated in 250 subjects aged 21-60 yr. The subjects were considered dentally aware since they had visited their dentist on a regular basis over the past several years. A high occurrence rate of cervical abrasion was noted with 85% of subjects exhibiting at least one superficial lesion. Manifest or deep lesions, although less common, were present in 22% of subjects. Both prevalence and severity increased with age. The severity expressed as the mean number of lesions was 7.3 for the total sample. It increased significantly with calculus index, frequency of periodontal pockets, and reduction of the alveolar bone height. No significant associations were observed between abrasion and oral hygiene factors. It is concluded that cervical abrasion, although most likely related to toothbrushing, may not be synonymous with periodontal health. Ineffective toothbrushing may not only fail to prevent disease but may also cause cervical abrasion.

Adult↗
PubMed1988

Elevated concentration of 5-hydroxytryptamine in ultrafiltrate of human liver vein plasma after infusion of amino acids.

Intragastric infusion of amino acids causes the release from the liver of a factor with stimulatory effect on smooth muscle. The effect of liver vein plasma ultrafiltrate was tested on isolated preparations of rat fundus. The ultrafiltrates collected after amino acid infusion had a 3-5 times higher stimulatory effect on smooth muscle contraction than those collected from control plasma. The active principle was isolated, purified by different chromatographic procedures and identified as 5-hydroxytryptamine (serotonin). No other compound with contractile effect on smooth muscle was detected.

Adult↗
PubMed1988

Cardiovascular function and arterial blood gases during sham dialysis in healthy man.

Cardiovascular function and alveolar gas exchange were studied in healthy subjects undergoing sham dialysis (SHD)--i.e. the circulation of blood through a cuprophane dialyzer with the dialysate compartment closed to avoid diffusion and convective transport of fluid and solutes. The blood-membrane contact induced complement activation (rise in C3d) and transient leukopenia, as described during clinical hemodialysis. PaO2, PaCO2 and calculated oxygen uptake remained unchanged. Heart rate, cardiac index (thermodilution), systemic vascular resistance index and brachial and pulmonary arterial blood pressures did not change significantly during 150 min of SHD (n = 8). In 12 subjects, in whom more frequent measurements were made during the first 30 min of SHD, pulmonary arterial systolic and diastolic blood pressures decreased significantly while the dialyzer and the tubing set filled with blood, and pulmonary arterial mean blood pressure did not change significantly. Pulmonary capillary wedge pressure fell during the filling phase, but did not change significantly during SHD; pulmonary vascular resistance index remained unchanged. We conclude that in nonuremic subjects sham dialysis with a cuprophane dialyzer does not result in hypoxemia, pulmonary vascular constriction and pulmonary hypertension, in spite of complement activation and marked leukopenia.

Acid-Base Equilibrium↗
PubMed1988

Cardiovascular function and arterial blood gases during isolated ultrafiltration in healthy man.

In order to recognize possible cardiovascular signs of underhydration during isolated ultrafiltration (IUF), we have studied the physiological hemodynamic adaptation to IUF in healthy man both above and below normohydration. In 7 subjects IUF was performed with the subjects in a normohydrated state at the start of IUF. In 8 subjects the IUF was preceded by a 1-hour infusion of Ringer solution equal to 3% of body weight. By invasive techniques, cardiac index (thermodilution), stroke index, heart rate, brachial and pulmonary arterial blood pressures, systemic vascular resistance index, central blood temperature, PaO2 and PaCO2 were measured. Calf vascular resistance was assessed by venous occlusion plethysmography. A recirculation period of 30 min was followed by IUF in both study groups. During IUF with overhydration and normohydration at the start of IUF, cardiac output fell because of a decline in stroke volume and an unchanged heart rate. Blood pressure remained constant because of systemic vascular constriction. PaO2 and PaCO2 remained unchanged. IUF in healthy man is mainly characterized by vascular constriction and an unchanged heart rate. Thus, the cardiovascular adaptation to ultrafiltration was the same whether or not ultrafiltration was performed at overhydration or normohydration at the start of ultrafiltration. Therefore, it is unlikely that monitoring of heart rate or noninvasive recording of blood pressure can predict whether a subject is becoming underhydrated during isolated ultrafiltration. The adaptation to IUF is similar to that observed during the treatment of uremic patients without complications.

Blood Gas Analysis↗
PubMed1988

Potential role of a liver-derived factor in mediating renal response to protein.

Increases in renal blood flow and glomerular filtration rate occur following the ingestion of a protein-rich meal. It has been postulated that this renal response is stimulated by some hormonal factor. Glucagon has been proposed as a probable mediating hormone, but results of recent studies argue against a direct mediating effect of glucagon. It is postulated that glomerular hyperfiltration induced by various stimuli (protein ingestion, amino acid infusion, glucagon infusion, diabetes mellitus) is associated with increased secretion by the liver of a factor that increases glomerular filtration rate. Preliminary data suggest that serotonin might play a role in mediating the postprandial increases in renal hemodynamics following protein ingestion.

Animals↗
PubMed1988

What is the role of controls in an outpatient department on progression of renal disease?

Evidence that protein restriction retards the progression of chronic renal failure in man is mostly derived from anecdotic data and retrospective studies with inappropriate controls and inferior methodology for evaluating renal function. Data from a prospective randomized study in Stockholm demonstrate that more frequent clinical follow-ups without changing the dietary intake of protein significantly retards the progression of renal failure and that the degree of retardation is correlated to improvement in blood pressure control.

Blood Pressure↗
PubMed1988

Protein and amino acid metabolism in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

Several factors contribute to impaired nutritional status in patients undergoing CAPD. The protein loss into the dialysate varies between 5-15 g per day; during peritonitis protein loss increases by 50-100%. The loss of free amino acids during CAPD is of the same magnitude as under hemodialysis. The observed plasma amino acid abnormalities in CAPD patients probably reflect metabolic derangements in uremia, rather than depletion due to dialysate amino acid loss. Sustained hyperinsulinemia in CAPD patients also may contribute to reduced plasma amino acid concentrations. A further factor contributing to nutritional problems in CAPD is a decreased protein intake. Dietary protein intake should exceed 1.2 g/kg/day during long-term CAPD treatment to maintain nitrogen equilibrium. Total energy intake may exceed 35 kcal/kg/day.

Amino Acids↗
PubMed1988

Periodontal health in Swedish professional musicians.

Periodontal health evaluated in terms of periodontal pocketing, tooth hypermobility and loss of teeth was studied and compared in musicians playing wind instruments and other instruments. 250 subjects aged 21-60 yr were examined. The number of teeth was high in both groups. No statistically significant differences between the groups were found with respect to pathological pockets or hypermobility. Regular playing of wind instruments did not seem to be associated with increased risk of deterioration in periodontal health.

Adult↗