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Biomedical subjects

K Derfler

Publications and source records attributed to K Derfler.

At least 73 records · Page 4Linked to original sources
PubMed1991

Impaired conversion of cortisol to cortisone in chronic renal insufficiency--a cause of hypertension or an epiphenomenon?

To study the possible impairment of 11 beta-hydroxysteroid-dehydrogenase in patients with chronic renal insufficiency, urinary excretion rates of the four main glucocorticoid-metabolites, tetrahydrocortisol, tetrahydrocortisone, allotetrahydrocortisol and allotetrahydrocortisone were determined by capillary gas chromatography in 22 patients with chronic renal insufficiency with (N = 15) and without (N = 7) hypertension, but without hemodialysis treatment. Whereas the sum of all 41 steroid metabolites determined by capillary gas chromatography was reduced (p less than 0.001) in patients with chronic renal insufficiency as compared with 22 healthy individuals, the relative contribution of the four glucocorticoid metabolites to total steroid excretion was similar in patients with renal insufficiency (22 +/- 12%) and in healthy subjects (20 +/- 5%). However, the excreted amount of tetrahydrocortisol exceeded that of tetrahydrocortisone in all but 3 (normotensive) patients with chronic renal insufficiency, but only in one healthy subject resulting, in patients with chronic renal insufficiency, in a ratio of tetrahydrocortisone vs tetrahydrocortisone of 0.7 +/- 0.4 (hypertensive patients 0.5 +/- 0.2; normotensive patients 1.1 +/- 0.4; controls 1.9 +/- 0.9, p less than 0.001 vs patients with chronic renal insufficiency). This ratio of tetrahydrocortisone/tetrahydrocortisol showed a correlation with serum concentrations of creatinine (p less than 0.001). These results provide indirect proof of an impaired conversion of cortisol to cortisone in moderate renal insufficiency and may suggest a relationship with the hypertension frequently seen in this group of patients.

Adult↗
PubMed1991

Duplex Doppler sonography in renal parenchymal disease. Histopathologic correlation.

To evaluate the histopathologic changes influencing Doppler measurements of the resistive index (RI) in renal arteries in renal parenchymal diseases, 68 kidneys in 34 consecutive patients with various forms of renal parenchymal diseases were studied by duplex Doppler ultrasound (duplex US) immediately before percutaneous renal biopsy. The RI, renal length, and renal cortical echogenicity were correlated with the amount of glomerular, interstitial, and vascular changes graded on a scale from 0 to 100. The renal vascular resistance and therefore the RI are significantly correlated with the prevalence of arteriolosclerosis, glomerular sclerosis, arteriosclerosis, edema, and focal interstitial fibrosis. There was no significant difference of the RI in five groups of different renal parenchymal diseases. Of 34 patients, 24 presented with an RI less than 0.7, which was thought to be within the normal range so far. Additionally, the RI increases as the patient's age increases, due to higher incidence of arteriosclerosis. Of our patients, 44% presented with normal cortical echogenicity. Quantitative duplex US using the RI does not reliably distinguish different types of renal medical disorders.

Adult↗
PubMed1991

Predictive value of thallium-201-dipyridamole myocardial stress scintigraphy in chronic hemodialysis patients and transplant recipients.

The prognostic impact of thallium(Tl)-201-dipyridamole (DPM) stress and redistribution scintigraphy done in 36 patients on chronic hemodialysis (HD) and in 23 renal transplant recipients (TRs) was evaluated according to cardiovascular complications and survival in a follow-up period of six years. Though symptomatic ischemic heart disease (IHD) was present in 33% of HD patients and in 17% of TRs, 50% and 39%, respectively, had Tl-201 findings indicative of IHD. The duration of HD treatment was similar for patients with an abnormal or normal scintigraphic finding. Abnormal Tl-201 results were seen more frequently in older patients. During follow-up, 27 of 36 HD-patients died, 16 had an abnormal and 11 a normal Tl-201-DPM finding; cardiovascular complications were the cause of death in 88% and 18% of these patients, respectively. Thus the incidence of death from fatal cardiac events was 12% per year at risk for the former and 1.9% per year at risk for the latter. In TRs survival was not different for patients with an abnormal or normal Tl-201 finding (56% vs. 64%). However, fatal or nonfatal cardiovascular events were seen more frequently in patients with an abnormal Tl-201 results (78% versus 7%; p less than 0.0001). Stepwise logistic analysis and survival analysis demonstrated Tl-201-DPM stress/redistribution scintigraphy to be the only predictor for identifying patients at increased risk for cardiovascular events. In patients with abnormal Tl-201-DPM scintigraphy subsequent survival was extended for symptomatic patients as compared to asymptomatic ones )30.3 +/- 21.6 versus 22.0 +/- 17.3 months; p less than 0.008).

Adult↗
PubMed1991

[Beta-N-acetylglucosaminidase (beta-NAG) as a parameter in the diagnosis and evaluation of primary glomerular and tubulointerstitial kidney diseases].

beta-N-acetylglucosaminidase (beta-NAG) and beta 2-microglobulin were assessed in two cohorts of patients with glomerular or tubulointerstitial diseases respectively. While beta-NAG activities did not differ statistically significantly between both groups, beta 2-microglobulin excretion was statistically highly significantly increased in the setting of tubulointerstitial diseases. On the whole mean beta-NAG activity at 37 degrees C and beta 2-microglobulin urinary excretion were elevated in both groups, when compared to normal controls. Increased beta-NAG activities above 10 U/g creatinine were associated with a marked increase of creatinine serum levels within 6 months in both, patients with glomerular and tubulointerstitial basic renal diseases. beta-NAG and beta 2-microglobulin are useful tools in diagnosis and assessment of renal diseases elucidating different aspects.

Acetylglucosaminidase↗
PubMed1990

["Membrane attack complex" formation in hemodialysis treatment].

The behaviour of plasma concentrations of the membrane attack complex (MAC) during haemodialysis was studied in 23 patients. An increase in the levels up to 250% of the initial value was noted when Hemophan or Cuprophan membranes were used. Patients dialyzed, with Polysulfon membranes showed only a slight increase in MAC levels. In the Hemophan and Cuprophan group a plateau developed lasting from 15 to 120 minutes after onset of the haemodialysis session. The MAC may serve as marker of biocompatibility. Furthermore, it seems to be involved in many untoward effects of haemodialysis treatment.

Complement Activation↗
PubMed1990

[Experiences and clinical results following 99 kidney transplantations with kidneys from relatives].

99 living related kidney transplantations were performed between January 1967 and December 1988. At the time of observation 4 of 94 organ donors had died; there was no correlation between unilateral nephrectomy and the patient's death. Intraoperative (2.9%) and postoperative (25%) complications did not result in severe physical consequences for the organ donors. Hypertension was found in 2 donors. There was no decrease in function of the remaining kidneys. The 3-year organ survival of the transplanted kidney was 60% with "conventional immunosuppression" and 93% with cyclosporin. No association was found between HLA DR-matching and graft survival. Rejection episodes occurred significantly more often in the HLA DR-mismatched grafts.

Adolescent↗
PubMed1990

Generation of the membrane attack complex during haemodialysis: impact of classical and alternative pathway components.

1. The generation of the plasma SC5b-9 complex (the soluble form of the membrane attack complex) during haemodialysis was studied in 29 patients together with markers of the classical (C4d fragment) and alternative (Bb fragment) pathways and the common iC3b fragment. 2. In the patients dialysed with Hemophan and Cuprophan membranes, a rapid increase in the plasma levels of SC5b-9 complex, Bb fragment and iC3b fragment occurred within 15 min of the initiation of the haemodialysis procedure. The SC5b-9 complex and the Bb fragment concentrations remained at a plateau until 120 min thereafter. The iC3b fragment level showed a continual decline. 3. The C4d fragment concentrations remained unchanged, indicating that generation of the membrane attack complex is most likely due only to activation of the alternative pathway. 4. The generation of the membrane attack complex occurred throughout the full haemodialysis period. In patients treated with Polysulfon membranes no statistically significant variation in these components was noted. 5. The study shows that the membrane attack complex may be generated during the full period of the haemodialysis session and is a stable index of biocompatibility. 6. Moreover, it seems be involved directly in haemodialysis-associated phenomena.

Complement Activation↗
PubMed1989

Mucin-like cancer-associated antigen (MCA) compared with CA 15-3 in advanced breast cancer.

Mucin-like cancer-associated antigen (MCA), a new tumor marker using the mouse monoclonal antibody b-12 is thought to be of value in the management of patients with breast cancer. In this study sera from 191 female patients with breast cancer (112 with progressive disease [PD] and 79 with no evidence of disease [NED]) were analyzed for MCA levels and compared with those of cancer antigen 15-3 (CA 15-3) in single determination and in combination with carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA). A cut-off level of 14 U/ml for MCA seems to be more appropriate than the recommended 11 U/ml to distinguish between PD and NED in patients with breast cancer. Although there was a fairly good correlation of MCA to CA 15-3, MCA was inferior in sensitivity and specificity to CA 15-3. Patients with osseous metastases and those with more than one metastatic site showed higher MCA levels than patients with visceral or soft tissue metastases, a fact which was comparable to CA 15-3. Combining MCA and CA 15-3 resulted in a gain in specificity but marked loss of sensitivity. The combination of MCA and CEA results also in a loss of sensitivity whereas the combination of CA 15-3 and CEA showed an increased specificity and only a negligible loss of sensitivity. The combination of MCA with TPA is of little value in the follow-up of breast cancer, as is the combination of CA 15-3 with TPA. The combination of CA 15-3 with CEA can be still recommended for follow-up for early detection of metastases in breast cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Optimal needle size for renal biopsy: in vitro and in vivo evaluation.

To evaluate the success and complication rates of small (16- and 18- gauge) needles in biopsy of the kidney, the authors performed in vitro biopsy in a cadaveric kidney and in vivo renal biopsy in 141 patients. Best results were obtained with a 16-gauge modified Menghini needle. In vitro, 9.7 +/- 5.7 (mean +/- standard deviation) glomeruli were retrieved, and the average length of tissue cores was 17.8 mm +/- 8.2. In vivo, 10.63 +/- 6.64 intact glomeruli were retrieved, and a definitive histologic diagnosis was achieved in 86% of patients. The frequency of major complications with this needle was 3.5%, and of minor complications, 5.8%. No major complications occurred after biopsy was performed with 18-gauge needles of the same design. However, the retrieval rate of glomeruli with these smaller needles was insufficient. An 18-gauge needle with two cutting edges yielded tissue cores of 11.0 mm +/- 3.5 in length. In vitro, 6.6 +/- 2.3 glomeruli were retrieved; in vivo, 9.92 +/- 6.65. A definitive histologic diagnosis was achieved with this needle in 75% of patients, and rates of 7.1% for major complications and 10.7% for minor complications were encountered.

Adult↗
PubMed1989

Transient hyperoxaluria after ingestion of chocolate as a high risk factor for calcium oxalate calculi.

In 6 male subjects the diurnal variation of urinary oxalic acid excretion was studied after ingestion of chocolate, a food stuff rich in oxalic acid. The ingestion of chocolate caused a striking but transient increase in urinary oxalic acid excretion due to its absorption in the upper gastrointestinal tract. The peak excretion rates occurred 2-4 h after the intake of the chocolate. The peak values were 235% of the fasting excretion rate in the trial with 50 g chocolate and 289% in the trial with 100 g chocolate and reached the amounts found in cases with primary hyperoxaluria. The administration of ranitidine had no influence on oxalic acid absorption. The transient hyperoxaluria observed seems to be an important factor for the formation of calcium oxalate calculi in patients on risk for stone disorders.

Adult↗