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Biomedical subjects

H Hedelin

Publications and source records attributed to H Hedelin.

At least 73 records · Page 4Linked to original sources
PubMed1990

Determination of prostate-specific antigen in serum by immunoradiometric assay.

A better understanding is needed of the role of pre-analytical factors if prostate-specific antigen (PSA) is to be reliably used as a tumor marker. Reports on the analytical performance of TANDEM-R PSA (Hybritech, Inc., San Diego, CA) differ considerably with respect to detection limit and imprecision, differences that might be due (e.g.) to the use of different control matrices, to between-batch variations in reagent composition, or to nonrobustness of the assay. During nine months we determined PSA in 986 serum samples from 728 male urology patients and 54 samples from women (25 assay runs). As controls we used two serum pools with low PSA concentration and two widely used commercial controls. The within-assay CV for patients' samples was similar to that found with the commercial controls: 2.6% to 3.4% in the upper part of the normal reference interval. Precision was worse at lower concentrations (CVs 5-10% at about 0.5 micrograms/L). Imprecision tended to be higher at the end of runs. Assay drift for 100-tube runs was -4%. PSA was stable at -20 degrees C during six months. Neither the polyester polymer in SST tubes nor a hemolysate had any detectable effect on PSA values. Clinical analysis of the first 322 patients and all patients with PSA less than or equal to 0.20 micrograms/L highlighted the requirements for strict adherence to sampling instructions and to stringent quality control also at low analyte concentrations (analyte-free sera and sera with PSA concentrations 0.2-0.5 micrograms/L). Values with TANDEM-R PSA and IRMA-Count PSA (Diagnostic Products Corp., Los Angeles, CA) correlated well with no difference in detection limit or with samples from women. Within-assay precision was better with IRMA-Count PSA in the upper part of the normal reference interval and above. The designs of the two assays were compared in a format that is generally applicable for immunoassay kits (NORDKEM kit group, unpublished), and subjective impressions were recorded.

Analysis of Variance↗
PubMed1989

The influence of zinc and citrate on urease-induced urine crystallisation.

Zinc reduced and citrate promoted the urease-induced pH increase in synthetic urine. Secondary to this, the precipitation of magnesium ammonium phosphate and calcium phosphate was influenced. Independent of this pH-related effect, zinc also increased the precipitation of magnesium ammonium phosphate and decreased the calcium phosphate precipitation. These observations were not totally reproducable in human urine.

Adult↗
PubMed1989

Chronic urinary tract infection and renal stones.

In patients with bacteriuria and small and otherwise asymptomatic renal stones, the infection should be linked to the stone before surgical removal of the stone is considered. In this study the level of infection was determined by ureteric catheterisation. The method could discriminate between stone-related infections (70%) and infections confined to the lower urinary tract (30%) in virtually all of the patients. Even very small stones (3 mm) were shown to be the cause of decade-long bacteriurias. The results of operative stone removal were encouraging, with eradication of the infection in 87% of the patients with stone-related infection.

Adult↗
PubMed1989

Morphological lesions of the rat urinary tract induced by inoculation of mycoplasmas and other urinary tract pathogens.

The effects on the urinary tract after inoculation of Ureaplasma urealyticum into the rat bladder were evaluated and compared to that seen after Mycoplasma hominis, Escherichia coli and Proteus mirabilis inoculation. The inoculation of the urease-producing organisms P. mirabilis and U. urealyticum were associated with the formation of struvite bladder stones and predominantly hyperplastic lesions of the bladder. The P. mirabilis inoculated rats also displayed marked pyelonephritis. A similar but much less pronounced reaction also occurred in the kidneys of some of the U. urealyticum inoculated rats. P. mirabilis could frequently be recultured. In contrast, this was not possible with U. urealyticum, but the organism was detected by scanning electron microscopy 2 weeks after the inoculation. Inoculation of M. hominis was associated with a few mild lesions of the bladder, but inflammatory lesions were not present in the kidneys. The study confirms the potential of Ureaplasma to form struvite stones in rat urinary tract. It also demonstrates that it can induce inflammatory changes in both bladder and kidney of rats without concomitant stone formation.

Animals↗
PubMed1989

Percutaneous renal and ureteric stone extraction. Report on the first 500 operations.

A consecutive series of the first 500 percutaneous renal and ureteric stone extractions in 451 patients was analysed. During the period studied, percutaneous extraction was offered to all patients with conventional indication for stone removal except a few, very early ureteric stone patients in whom open lithotomy was carried out. Ureteroscopy and extracorporeal shock wave lithotripsy had not come into routine use. Four hundred and seventy-eight stone operations (96%) could be performed by the percutaneous route; early in the series, 21 open operations and one transurethral Dormia basket extraction were performed, mainly because of failed mobilisation of ureteric stones (12 patients) or various peroperative complications (9 patients). The target stones were completely removed in 88% of all percutaneous procedures, with the best results in the largest group of patients with 6-20 mm solitary stones or 2-3 stones less than or equal to 10 mm. Stones in the ureter and pelvi-ureteric junction without any other concomitant stones were all completely removed. Bleeding was the most frequent peroperative complication. No kidney was lost. An 84-year-old man died of intercurrent disease postoperatively.

Female↗
PubMed1988

Adherence of urease-induced crystals to rat bladder epithelium.

Apart from urine supersaturation with respect to struvite and calcium phosphate caused by urease-producing microorganisms, retention of formed crystals in the urinary tract is necessary for the formation of infection stones. This study was performed to investigate the role of the mucous coat lining the urothelium in the adhesion of urease-induced crystals. Removal of this glycosaminoglycan-containing layer from rat bladders increased the adherence of struvite and calcium phosphate crystals 5-6 times compared to that in intact rat bladders. Heparin completely restored the antiadherence capacity while chondroitin sulphate had a very weak restorative effect and human urine had no restorative effect. These findings support the view that the mucous coat is of importance in preventing retention of urease-induced crystals.

Animals↗
PubMed1988

Adherence of urease-induced crystals to rat bladder epithelium following acute infection with different uropathogenic microorganisms.

Apart from urine supersaturation with respect to struvite and calcium phosphate, crystal retention is considered to be necessary for the formation of infection stones. This study was performed to investigate the role of the mucous coat in rat bladders in the adhesion of sterile urease-induced crystals and to determine to what extent the adhesion was influenced by infection. Elimination of the mucous coat with 0.1 M HCl increased the adherence of crystals six times compared to that in bladders with an intact mucous coat. Infection with Proteus mirabilis, Escherichia coli, enterococci and Ureaplasma urealyticum increased the adherence six, five, four and two times, respectively. Injury to the mucous coat may thus be one mechanism by which microorganisms can contribute to the formation of infection stones in the urinary tract.

Animals↗
PubMed1988

Effects of indwelling catheters on the urethral mucosa (polypoid urethritis).

Indwelling catheters are almost invariably associated with characteristic mucosal lesions of the urinary bladder, commonly referred to as polypoid cystitis. In the present study, 20 male patients with indwelling catheters (due to benign prostatic hyperplasia) for 1-12 months were studied. Three non-catheter bearing male patients served as controls. Biopsies were taken from the posterior urethra in all patients and from the bladder in 16 of the 20 patients with indwelling catheters. All patients with catheters had endoscopic lesions in the urethra. The lesions varied from polypoid to bullous or oedematous, with or without hemorrhagic discoloration. In 11 of 20 patients the urethral lesions were histologically almost identical to polypoid cystitis. In the remaining 9 patients the reaction was less pronounced, and oedema, with or without mucosal hemorrhage, dominated. Due to the similarity between the catheter associated bladder lesions and the urethral lesions we suggest the term polypoid urethritis for the urethral lesions. There was no correlation between type of catheter used or how long it was used and the mucosal lesions. The results suggest mechanical irritation and/or pressure exerted by the catheter on the mucosa is responsible for the development of polypoid urethritis.

Aged↗
PubMed1988

Percutaneous surgery for stones in pyelocaliceal diverticula.

The technique used for percutaneous extraction of stones in pyelocaliceal diverticula and the results of the procedure in 13 patients are presented. Nine patients have been free of their pre-operative symptoms, pain and/or bacteriuria, since removal of the stones.

Adult↗
PubMed1988

Urinary infection stones caused by Ureaplasma urealyticum: a review.

Experimental and clinical studies have been performed to determine whether Ureaplasma urealyticum has an etiological role in the development of infection stones in the urinary tract. Incubation of synthetic urine in vitro with U. urealyticum caused alkalinization of the urine and crystallization of struvite and calcium phosphate. Inoculation of U. urealyticum into rat bladders resulted in the formation of struvite stones in 84% of the rats. Furthermore, infection with U. urealyticum markedly increased the adherence of urease-induced crystals to the bladder epithelium compared to normal rat bladders, probably due to elimination of the mucous coat which covers the normal urothelium. Clinically, U. urealyticum has been cultured from voided urine and from the stone in patients operated on for renal stones. U. urealyticum was cultured in voided urine in 31 of 247 patients (13%) with metabolic stones, compared to 43 of 145 patients (30%) with infection stones (p less than 0.001). In the patients where stone cultures were performed, U. urealyticum was found in 2 of 125 patients (2%) with metabolic stones, compared to 10 of 64 patients (16%) with infection stones (p less than 0.001). These observations strongly suggest that U. urealyticum is linked to the formation of infection stones in the urinary tract.

Animals↗
PubMed1986

The effects of glycosaminoglycans, pyrophosphate and allopurinol treatment on urease-induced crystallization in vitro.

Previous studies have found that human urine inhibits urease-induced crystallization in synthetic urine. To identify the inhibitory components the effects of chondroitin sulphate, heparin and pyrophosphate on urease-induced crystallization were studied and the inhibitory capacity of human urine collected during and before/after allopurinol treatment compared. None of the substances studied nor allopurinol treatment was found to influence the urease-induced crystallization. These findings do not support the idea that glycosaminoglycans or pyrophosphate are responsible for the inhibitory effect detected in human urine.

Allopurinol↗
PubMed1986

The effects of urease in undiluted human urine.

Undiluted human urine and synthetic urine were inoculated with urease. No inhibitory activity against urease enzymatic activity could be detected in human urine. The urease-induced crystallization of both calcium phosphate and magnesium ammonium phosphate differed markedly, however, between the individuals studied, and it was less pronounced in human urine than in synthetic urine. This supports the observation made in experiments using diluted urine that human urine possesses an inhibitory activity against urease-induced crystallization and suggests that it has a large interindividual variation.

Adult↗
PubMed1986

The inhibitory effect of human urine on urease-induced crystallization in vitro.

To study whether human urine contains inhibitors against urease-induced crystallization, Jackbean urease and human urine, in amounts small enough (0.5 to 10 per cent) not to influence the ion concentration, buffering capacity or pH, were added to synthetic urine. The ammonia production and alkalinization that followed were independent of the amounts of human urine added. The addition of human urine gave a dose-related decrease in the amount of calcium phosphate and struvite precipitated on glass rods immersed in the synthetic urine, however. Addition of only 0.5 per cent human urine gave a reproducible decrease and when 10 per cent human urine was added to the synthetic urine the precipitation of calcium phosphate was reduced by 50 per cent and that of struvite by 75 per cent. The results thus indicate that human urine contains components with the ability to reduce the urease-induced crystallization.

Adult↗
PubMed1986

Rapidly recurrent renal calculi caused by Ureaplasma urealyticum: a case report.

We report on a patient operated upon 8 times for recurrent bilateral struvite stones. Multiple conventional bacterial cultures had been negative. No etiological agent for the rapidly recurring concrements could be detected until Ureaplasma urealyticum cultures were performed at the time of the seventh operation. Ureaplasma urealyticum was found in the bladder and renal pelvic urine, and in the stones. That operation was followed by appropriate antibiotic treatment (doxycycline), which eradicated the microorganism and no stones recurred for 6 months. The urinary pH, which constantly had been highly alkaline before treatment, was normal as was the ammonium loading test. However, 1 year after the seventh operation the Ureaplasma infection recurred, probably due to sexual transmittance, and a new renal stone was discovered. These findings strongly suggest that Ureaplasma urealyticum can induce the formation of infection concrements.

Bacteriuria↗
PubMed1985

Concrement formation in the urinary bladder in rats inoculated with Ureaplasma urealyticum.

To study the concrement-forming ability of Ureaplasma urealyticum in the urinary tract, viable and heat-killed ureaplasmas as well as urease and non-urease-producing bacteria were inoculated into the bladder in rats. Viable ureaplasmas, in contrast to heat-killed, caused the formation of bladder stones with a frequency corresponding to urease-producing bacteria (Proteus mirabilis). It was not possible to reculture the inoculated ureaplasmas from the urinary tract. Non-urease producing microorganisms (Escherichia coli and Mycoplasma hominis) only occasionally induced stone formation. The results indicate that U. urealyticum can initiate stone formation, a property that appears to be associated with the urease activity of the organism.

Animals↗