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Biomedical subjects

T Eklund

Publications and source records attributed to T Eklund.

At least 19 recordsLinked to original sources
PubMed2000

Change of bone tissue composition and impaired bone strength in rats exposed to 3,3',4,4',5-pentachlorobiphenyl (PCB126).

The aim of this study was to compare effects of estrogen depletion (ovariectomy) and exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB126) on bone strength and bone tissue composition in the rat. Half of the rats were ovariectomized (n=20) and the remainder were sham-operated. Ten of the ovariectomized rats and ten of the sham operated were exposed to PCB126 (ip injections) for 3 months (total dose, 384 microgram/kg bodyweight), while those remaining received the vehicle. The humerus and femur were used for analysis of torsional strength and biochemical studies, respectively. Both sham-operated and ovariectomized animals showed a significantly shorter bone length, lower water content and a decreased torsional stiffness when exposed to PCB126. Sham-operated rats exposed to PCB126 had lower maximum torque when compared with sham operated controls. The PCB126-exposed rats also exhibited a significantly lower collagen concentration, but showed a higher pyridinoline concentration of cortical bone. PCB126 exposure decreased the hepatic level of vitamin A but increased vitamin A levels in serum and kidneys. Ovariectomy per se increased bone length and organic content and decreased the inorganic content significantly, but did not affect any of the tested biomechanical parameters. In conclusion, this study showed that the common environmental pollutant PCB126 impaired bone strength and altered bone composition. It is hypothesized that these effects might partly be explained by PCB-induced retinoid disturbances.

Animals↗
PubMed1998

Value of sextant biopsies in the assessment of local cure following external beam radiotherapy of prostatic adenocarcinoma.

Between 1982 and 1992, 73 patients received radical external beam radiotherapy (EBR) for prostatic adenocarcinoma at the Central Hospital, Västerås, with an average dose of 68.1 Gy (range 64.5-72.5 Gy) and an average cumulative radiation effect (CRE) of 18.2 (range 17.1-19.9) All patients had a negative bone scan prior to treatment and presented with clinical stage T1-T4,Nx,Mo. Twenty-four out of 36 surviving patients consented to participate in a follow-up study which included transrectal, ultrasonically guided prostate biopsies. The average follow-up from EBR to biopsy was 5.5 years (range 3.6-11.1 years). Sixteen (67%) of the patients had a positive biopsy. The average PSA level in the biopsy-positive group was 35.7 ng/mL (range 3.9-200 ng/mL). In the biopsy-negative group, the average PSA was 3.7 ng/mL (range 0.2-13.0 ng/mL). The conclusion is that the degree of local cure achieved in patients with prostatic cancer treated with external beam radiotherapy is low (33%), and that a higher radiation dose may be required to eradicate this malignancy.

Adenocarcinoma↗
PubMed1997

Altered dopamine function in pathological gambling.

BACKGROUND: The possibility that monoaminergic neurotransmission is altered in pathological gambling was examined. METHODS: Monoamines and their metabolites were measured in CSF obtained at level L4-5 from ten pathological gamblers and seven controls. RESULTS: A decrease in dopamine and an increase in 3,4-dihydroxyphenylacetic acid and homovanilic acid was found. Noradrenaline and its metabolite 3-methoxy-4-hydroxyphenylglycol was also increased but 5-hydroxytryptamine and 5-hydroxyindoleacetic acid were unchanged. CONCLUSION: It is suggested that the function of the dopaminergic system, possibly mediating positive and negative reward, and the noradrenergic system, possibly mediating selective attention, is changed in pathological gambling.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1993

Microculture model studies on the effect of sorbic acid on Penicillium chrysogenum, Cladosporium cladosporioides and Ulocladium atrum at different pH levels.

The minimum growth-inhibitory concentration of sorbic acid has been determined for Penicillium chrysogenum, Cladosporium cladosporioides and Ulocladium atrum at pH 4.1-7.6 by using a microculture technique. This technique had earlier been applied to bacteria and Candida albicans and gave very reliable minimum inhibitory values. This investigation has shown that it is suitable also for determination of mould growth. The minimum inhibitory concentrations of sorbic acid were at the tested pH levels 1-230 mmol l-1 for P. chrysogenum, 0.3-18.0 mmol l-1 for C. cladosporioides and 0.2-33.0 mmol l-1 for U. atrum. A mathematical model for combined inhibition by dissociated and undissociated acid, which gave a good description of the minimum inhibitory concentration data earlier obtained for bacteria and Candida albicans, was suitable also for moulds. Both dissociated and undissociated acid contributed to growth inhibition.

Cladosporium↗
PubMed1991

Interstitial lactate, inosine and hypoxanthine in rat kidney during normothermic ischaemia and recirculation.

The aim of this study was to determine the potential value of extracellular fluid (ECF) lactate, inosine and hypoxanthine for monitoring the disturbance in energy metabolism associated with kidney ischaemia and recirculation, using intrarenal microdialysis as sampling technique. Normothermic ischaemia was produced in rats by clamping of the left renal pedicle. Microdialysis probes were implanted into the renal cortex and the medulla, respectively. Dialysates were collected in 10-minute fractions before, during 20 (Group A) or 40 minutes (Group B) ischaemia and 2 hours of recirculation. Samples were analysed by HPLC for lactate, inosine and hypoxanthine. Ischaemia caused a dramatic increase of extracellular fluid lactate, inosine and hypoxanthine in both groups, reflecting the disturbance of energy metabolism. The basal extracellular fluid level of lactate as well as that during ischaemia was markedly higher in the medulla compared to cortex, whereas the relative change in lactate concentration was similar (i.e. about 4-fold). In group A all three metabolites returned to the pre-ischaemic level within 20 minutes after reperfusion. However, while inosine and hypoxanthine returned promptly to base line in Group B, recovery of lactate varied dramatically between animals suggesting a persistent metabolic disturbance in some rats. Our results indicate that extracellular fluid lactate, inosine and hypoxanthine, measured by intrarenal microdialysis, may be useful for monitoring of the energy state of the kidney during normothermic ischaemia and that extracellular fluid lactate may be a sensitive indicator of post-ischaemic disturbances in energy metabolism.

Animals↗
PubMed1991

Experience with vascular access for acute renal failure: using Buselmeier shunt and femoral vessel catheter.

Three types of vascular access were evaluated over a period of 2 years, January 1987-December 1989, in 76 critically ill acute renal failure (ARF) patients. The Buselmeier shunt comprised 75% of the acute vascular access which were utilized, the cannulation of the femoral vessel 23% and the Scribner shunt 2%. The Buselmeier shunt was successfully used alone (mainly in the forearm) in 58 patients for continuous arteriovenous hemofiltration, continuous arteriovenous hemodialysis and intermittent hemofiltration. Thrombosis was noted in 7% of the shunts, where the majority needed a new shunt either on the same or the contralateral arm. Blood leakage was noted in 2%, hematoma in 1%, and accidental bleeding in 1% of the shunts. This study showed that the Buselmeier shunt is more used in our center, most likely because it is easy to bypass the hemodialysis filter by the staff nurse in case of clotting. No major complications were noted even if kept in place for a longer period of time. It offers adequate blood flow for continuous renal replacement therapy and intermittent hemofiltration in ARF.

Acute Kidney Injury↗
PubMed1988

Inhibitory mechanisms of Maillard reaction products.

In order to determine the inhibitory mechanism of antibacterial Maillard reaction products (MRP), heated mixtures containing arginine and xylose (AX) or histidine and glucose (HG) were studied for their mutagenic effect, using the Salmonella mutagenic test system ('Ames test'), with regard to their effect on the uptake of serine, glucose and oxygen and for their effect on iron solubility. It was found that the MRPs tested had little or no mutagenic effect, while an inhibitory effect on the uptake of serine, glucose and oxygen was observed. The MRPs also had an effect on the solubility of iron in nutrient broth and in phosphate buffer. While the AX mixture reduced the solubility of iron it was increased by the HG mixture. The reduction of iron solubility in the presence of the AX mixture was much greater at pH 8 than at pH 5. The present data suggest that the antibacterial effect of the MRPs tested is primarily due to the interaction between MRPs and iron, resulting in reduced oxygen uptake.

Arginine↗
PubMed1987

Penile cancer: is there an epidemiological role for smoking and sexual behaviour?

A retrospective study was carried out to determine whether penile cancer, like cervical cancer, was associated with smoking and sexual behaviour. Altogether 244 men with penile cancer and 232 matched controls completed a questionnaire by post or telephone. Data on marital state, socioeconomic group, occupation, history of phimosis and balanitis, sexual behaviour, and smoking were obtained. The results of statistical analyses confirmed that phimosis and balanitis were risk factors for penile cancer, but there was no epidemiological evidence for it being a sexually transmitted disease. Smoking was a risk factor with a dose-response relation and remained associated with penile cancer even after adjustment for confounding factors. Penile cancer is associated with smoking independently of phimosis; treatment of phimosis alone does not remove the risk caused by smoking.

Aged↗
PubMed1985

The effect of sorbic acid and esters of p-hydroxybenzoic acid on the protonmotive force in Escherichia coli membrane vesicles.

The effect of three food preservatives, sorbic acid and methyl and butyl esters of p-hydroxybenzoic acid, on the protonmotive force in Escherichia coli membrane vesicles was investigated. Radioactive chemical probes were used to determine the two components of the protonmotive force: delta pH (pH difference) and delta psi (membrane potential). Both types of compound selectively eliminated delta pH across the membrane, while leaving delta psi much less disturbed indicating that transport inhibition by neutralization of the protonmotive force cannot be the only mechanism of action for the food preservatives tested.

Biological Transport↗
PubMed1983

The effect of parabens on DNA, RNA and protein synthesis in Escherichia coli and Bacillus subtilis.

The effect of methyl, propyl and butyl esters of p-hydroxybenzoic acid on DNA and RNA synthesis has been tested in toluenized cells of Escherichia coli and Bacillus subtilis. Both RNA and DNA synthesis of these bacteria were inhibited. The inhibitory concentrations were higher than those previously reported for growth inhibition. Protein synthesis in cell-free extracts (S-30 fraction) of B. subtilis was even more sensitive to parabens than DNA and RNA synthesis, while protein synthesis in Esch. coli was largely unaffected.

Bacillus subtilis↗
PubMed1983

The antimicrobial effect of dissociated and undissociated sorbic acid at different pH levels.

The minimum inhibitory concentration of sorbic acid has been determined for Bacillus subtilis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. The inhibition was shown to be due to both undissociated and dissociated acid, and the effect of each has been calculated in accordance with a proposed mathematical model. Although the inhibitory action of undissociated acid was 10-600 times greater than that of dissociated acid, the latter caused more than 50% of the growth inhibition at pH levels above 6 for most of the organisms tested.

Bacillus cereus↗
PubMed1983

Microculture model studies on the effect of various gas atmospheres on microbial growth at different temperatures.

A microculture technique, employing 96-well tissue culture plates in plastic bags, was used to test the effect of different gas atmospheres (vacuum, air, nitrogen, and carbon dioxide) on the growth of Escherichia coli, Bacillus macerans, Salmonella typhimurium. Candida albicans, Lactobacillus plantarum, Pseudomonas/Acinetobacter/moraxella-group, Brochothrix thermosphacta and Yersinia enterocolitica at 2, 6, and 20 degrees C. In general, carbon dioxide was the most effective inhibitor. The inhibition increased with decreasing temperature. Only the combination of carbon dioxide and 2 degrees C provided complete inhibition of Broch. thermosphacta and Y. enterocolitica.

Actinomycetales↗
PubMed1977

Dynamics of x-ray-induced reversion in heterogeneous S. cerevisiae populations.

The survival and frequency of adenine and homoserine revertants after X-irradiation have been studied in starved and growing populations of haploid S. cerevisiae (strain 5483/1b). A growing population is heterogeneous to cell killing, and a mathematical model can be used to determine possible correlation between sensitivity to killing and sensitivity to mutation induction. The results indicate correlation between sensitivity to ade2-1 reversion and sensitivity to cell killing, whereas no such correlation was found between sensitivity to hom3-10 reversion and sensitivity to killing. The difference in the dynamics of homoserine and adenine reversions was reduced by adding caffeine to the post-irradiation media.

Adenine↗