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Biomedical subjects

B Kreft

Publications and source records attributed to B Kreft.

At least 19 recordsLinked to original sources
PubMed2006

Late reactions to the patch-test preparations para-phenylenediamine and epoxy resin: a prospective multicentre investigation of the German Contact Dermatitis Research Group.

BACKGROUND: Late patch-test reactions, developing at day (D) 7 or later have been described for several allergens. Late reactions may reflect patch-test sensitization. Para-phenylenediamine (PPD) and epoxy resins (ER) are potent allergens and therefore may potentially induce patch-test sensitization. Up to now, there has been no prospective study on the frequency of late reactions in routine patch testing with these allergens. OBJECTIVES: To assess the frequency of late reactions to PPD and ER. PATIENTS/METHODS: In 1748 patients PPD (PPD-base, 1% pet.) and ER [based on diglycidylether of bisphenol A (DGEBA, 1% pet.)], and in 812 patients, nickel sulphate (5% pet.) were removed from the test panel of the standard series and applied on the medial side of the upper arm. Patch-test occlusion time was 24 h in 588 (PPD and ER) and 241 patients (nickel sulphate), respectively, and 48 h in 1160 (PPD and ER) and 571 (nickel sulphate) patients, respectively. Patch tests were read on D1-3 and D2-3, respectively; additional late readings were performed on D7, D14 and D21 after patch-test application. Patients who were not able to return for all scheduled late readings were telephoned on D7, D14 or D21, and questioned about a reaction at the test sites. Patients were instructed to perform daily self-examination from D4 onwards and to return immediately to the clinic if a reaction at the upper arm became visible. RESULTS: Data of 1428 patients (ER and PPD) and 638 patients (nickel) were evaluable. In 25 patients (1.8%), patch tests became positive not before D7, among them 21 reactions to PPD (1.5%) and four reactions to ER (0.3%). In five of seven patients, repeated patch tests with PPD disclosed patch-test sensitization as the cause of the late reaction. All late reactions, except for one, occurred in patients in whom patch tests were applied for 48 h. No late reactions were seen with nickel sulphate. CONCLUSIONS: PPD (1% pet.) elicited late reactions in 1.5% of routine patch tests, the majority of them probably being caused by patch-test sensitization. Therefore, the German Contact Dermatitis Research Group decided to remove PPD 1% pet. from the German standard series and to take efforts to optimize the patch-test conditions of PPD. One way to optimize PPD testing could be to reduce the exposure of PPD 1% to 24 h. Alternatively the patch-test concentration of PPD might be reduced.

Adolescent↗
PubMed2005

[Radiologic features of inflammatory pseudotumors].

Inflammatory pseudotumor is a rare benign tumor entity. Because inflammatory pseudotumors mimic malignant tumors both clinically and radiologically, the radiologist should be familiar with this entity. Inflammatory pseudotumor most commonly involves the lung and the orbit, but it has been reported to occur in nearly every site in the body. For making a definite diagnosis a biopsy is often essential. The treatment options are varied and consist of surgery, high-dose steroids, irradiation, and chemotherapeutics.

Adult↗
PubMed2004

[Diagnostic imaging of vascular leiomyosarcomas].

Primary vascular leiomyosarcomas are very rare tumors, with the venous variety most often arising from the inferior caval vein and the arterial variety from the pulmonary artery. The tumors show either an exclusive intra- or extravascular pattern or a mixed growth pattern. The clinical symptoms depend on tumor location, with intraluminal tumors of the inferior caval vein causing edema or a Budd-Chiari syndrome. Leiomyosarcomas of the pulmonary artery can mimic chronic central or recurrent peripheral pulmonary embolism. Contrast enhanced spiral CT with multiplanar reconstruction is the diagnostic method of choice when a vascular leiomyosarcoma is suspected. MRI with MR-angiography can be added. If a tumor of undetermined origin shows a broad contact with a vessel and/or an intraluminal component, possible primary vascular leiomyosarcoma should be included in the differential diagnosis.

Budd-Chiari Syndrome↗
PubMed2004

Unilateral nevoid telangiectasia syndrome.

We report on a 29-year-old patient with a unilateral nevoid telangiectasia syndrome (UNTS). Based on microcirculation examinations, both functional impairments at the blood vessel level (laser-Doppler flowmetry) and morphologically altered capillaries (capillary microscopy) could be observed. We could demonstrate that microcirculatory examinations are suitable to demonstrate pathophysiological defects at the vascular level, especially since subclinical functional defects can also be recorded. To our knowledge, no such observations have yet been published with regards to UNTS.

Adult↗
PubMed2004

Vasculitic purpura with antineutrophil cytoplasmic antibody-positive acute renal failure in a patient with Streptococcus bovis case and Neisseria subflava bacteremia and subacute endocarditis.

Subacute bacterial endocarditis is frequently associated with extracardiac manifestations and renal failure. Clinical variety of endocarditis manifestation is wide and has the potential to mimic vasculitis. Whereas Streptococcus bovis is often isolated and associated with colonic tumors, Neisseriaceae are rarely found. An association of subacute bacterial endocarditis and antineutrophil cytoplasmic antibodies has been described. We report on a 62-year-old man who was admitted to our hospital with acute oliguric renal failure and a nonpruritic purpural rush without fever. Antineutrophil cytoplasmic antibody diagnostic revealed perinuclear staining with a titre of 1 : 512 and antiproteinase-3 specificity. Immune complex-mediated glomerulonephritis without extracapillary proliferation was diagnosed in renal biopsy. Finally, blood cultures became positive for Streptococcus bovis and Neisseria flava. Echocardiography showed mobile vegetations on tricuspid valve. Under treatment with penicillin G and gentamicin, skin efflorescences and renal function recovered, but vegetations increased. A colonic tumor could be excluded, a disastrous dental status may have been a predisposal factor. When classical findings of subacute bacterial endocarditis are less clear, the presence of renal failure and antineutrophil cytoplasmic antibodies in absence of fever may lead to misdiagnosis and deleterious immunosuppressive therapy. Neisseria subflava, an upper respiratory tract commensal, may cause subacute bacterial endocarditis without typical symptoms.

Acute Kidney Injury↗
PubMed2004

Renal perfusion imaging using contrast-enhanced phase-inversion ultrasound.

AIMS: We evaluated different techniques of contrast-enhanced phase-inversion ultrasound to visualize renal perfusion in native kidneys and kidney transplants. MATERIALS AND METHODS: Contrast-enhanced phase inversion ultrasound with different levels of mechanical index and frame rate was performed in 20 kidneys of 13 healthy volunteers. In addition, five dysfunctioning kidneys of patients with chronic renal failure, five functionally intact kidney transplants, three kidney transplants with compensated renal failure, and two kidney transplants with acute rejection were studied. Analysis using a software algorithm for time-resolved perfusion imaging was compared to single-image analysis performed by three independent radiologists. RESULTS: Optimal depiction of renal perfusion was achieved only by using a mechanical index, which was high enough to destroy the microbubbles of the contrast agent (burst imaging) combined with a low frame rate (0.5 images/second). Renal cortex and medulla showed a homogeneous enhancement in kidneys of healthy volunteers and functionally intact renal transplants. Dysfunctioning kidneys of patients with chronic renal failure as well as kidney transplants with compensated renal failure or acute rejection showed a significantly reduced level of enhancement. Computer-assisted time-resolved perfusion analysis was not superior to single-image analysis. CONCLUSION: Renal perfusion patterns of normal and abnormal tissue can be visualized using contrast-enhanced phase-inversion ultrasound imaging.

Adult↗
PubMed2003

[Congenital and postpartum ungues incarnati].

A 2 month old infant presented with ingrown toenails of both great toes with an accompanying inflammatory reaction. The appearance of the toenails became normal after 6 months of topical antiseptic and anti-inflammatory treatment.

Administration, Topical↗
PubMed2003

[Cystic renal lesions].

Cystic renal lesions are most often simple or complicated cysts, which can be seen solitary or as part of cystic renal disease. The minority of these lesions are benign or malignant cystic tumors. The classification of cystic renal masses by Bosniak (category l - IV) based on specific ultrasound and CT features is very useful for the characterization of the lesion and for the therapeutic decision. The main objective of this classification is to differentiate nonsurgical (category II) from surgical cystic masses (category III/IV). Ultrasound is the first modality of choice in the diagnostic work-up of cystic renal masses, because an accurate and economically reasonable diagnosis of the frequent simple cyst can be made by maintaining rigid ultrasound criteria of the Bosniak classification. If a complicated cyst or a cystic tumor is suspected a three phasic contrast-enhanced CT of the kidneys should be performed. MRI is superior to CT in the characterization of complex cystic masses.

Cost-Benefit Analysis↗
PubMed2002

[Is a dynamic MRI examination of the pancreas still necessary?].

PURPOSE: Evaluation of the diagnostic potential of a dynamic MR examination of the pancreas. MATERIAL AND METHODS: Retrospective study on 49 patients who underwent MRI of the pancreas (2 insulinomas, 2 cystadenomas, 19 pancreatic carcinomas, 26 patients with chronic pancreatitis). Interpretation was done in two steps: Initial evaluation of T2-weighted TSE-sequences, T1-weighted gradient echo sequences before and after injection of Gadolinium-DTPA i. v. Afterwards, additional evaluation of a dynamic contrast-enhanced MRI series of the pancreas with four dynamic scans. RESULT: Dynamic MR examination of the pancreas is useful in case of insulinomas. However, in case of pancreatic cancer an additional dynamic MR examination of the pancreas does not provide further clinically relevant information. CONCLUSION: In patients with a suspicion of pancreatic cancer, the injection of contrast material should preferably be used for the performance of a contrast-enhanced MR angiography at the expense of a dynamic MR examination.

Carcinoma↗
PubMed2002

[MRI in cavernous transformation of the portal vein: secondary biliary abnormalities and portoportal collaterals].

PURPOSE: Evaluation of portoportal collateral vessels and associated biliary abnormalities in patients with cavernous transformation of the portal vein by MRI. MATERIAL AND METHODS: Review of 34 MRI examinations performed on patients with angiographically or MR-angiographically proven cavernous transformation. The analysis included the pattern of the portoportal collateral circulation and the abnormalities of the biliary system, such as wall thickening, stenosis, dilations and irregularities of the extra-and intrahepatic bile ducts. RESULTS: 23 (67.6%) of 34 patients with cavernous transformation had paracholedochal portoportal collateral vessels, with 22 (64.7%) showing visible luminal channels. Epicholedochal venous collaterals could be observed in 8 (23.5%) patients. 24 (70.5%) of 34 patients demonstrated biliary abnormalities due to portoportal collaterals, leading to stenosis with dilatation of the proximal bile ducts in 8 (23.5%) patients. The ductal walls were irregular in 7 (20.5%) patients, and thickened in 11 (32.3%). The gallbladder wall was thickened in 4 (12.9%) patients. CONCLUSION: Portoportal collaterals in patients with cavernous transformation of the portal vein can be identified by MRI. These collaterals frequently alter the biliary system, which must be considered in differential diagnosis of biliary abnormalities observed in the presence of portoportal collaterals.

Adult↗
PubMed2002

Polarized expression of Tamm-Horsfall protein by renal tubular epithelial cells activates human granulocytes.

In renal bacterial infections granulocytes are of major importance in the primary immune defense against invading pathogens. However, the mechanisms of granulocytic activation in renal interstitial invasion have not been clarified. Renal tubular epithelial cell mechanisms inducing granulocytic activation and bacterial killing may include tubular cell expression of Tamm-Horsfall protein (THP), a urinary protein that is known to enhance cytokine expression in monocytes. We studied the role of THP in granulocytic activation. A strong binding of THP to human granulocytes was demonstrated by fluorescence-activated cell sorter analysis. Urinary THP and supernatants of THP-expressing cultured tubular epithelial cells (MDCK) enhanced interleukin-8 (IL-8) expression by human granulocytes. Renal tubular cells growing polarized on polycarbonate membranes were used to study apical versus basal THP expression. By electron microscopy THP immunoreactivity was exclusively found on the apical surfaces of tubular cells and was absent on the basolateral cell membrane. In the apical cell culture compartment we found significantly more stimulatory activity for granulocytic IL-8 expression. CD62L, a selectin less expressed in activated granulocytes, was decreased in granulocytes incubated with urinary THP and in supernatants of THP-producing renal tubular cells but not in supernatants from THP-negative cells. Again, the effect on CD62L expression was found only in apical culture media and was absent in the basal compartment. In summary our data give evidence that renal tubular cell THP expression may be relevant in kidney diseases since THP is a potent activator of human granulocytes. The regulation of apical versus basal THP expression and release in vivo may be crucial in the induction of the inflammatory response, e.g., in bacterial renal diseases.

Animals↗
PubMed2001

Glucocorticoids inhibit MAP kinase via increased expression and decreased degradation of MKP-1.

Glucocorticoids inhibit the proinflammatory activities of transcription factors such as AP-1 and NF-kappa B as well as that of diverse cellular signaling molecules. One of these signaling molecules is the extracellular signal-regulated kinase (Erk-1/2) that controls the release of allergic mediators and the induction of proinflammatory cytokine gene expression in mast cells. The mechanism of inhibition of Erk-1/2 activity by glucocorticoids is unknown. Here we report a novel dual action of glucocorticoids for this inhibition. Glucocorticoids increase the expression of the MAP kinase phosphatase-1 (MKP-1) gene at the promoter level, and attenuate proteasomal degradation of MKP-1, which we report to be triggered by activation of mast cells. Both induction of MKP-1 expression and inhibition of its degradation are necessary for glucocorticoid-mediated inhibition of Erk-1/2 activation. In NIH-3T3 fibroblasts, although glucocorticoids up-regulate the MKP-1 level, they do not attenuate the proteasomal degradation of this protein and consequently they are unable to inhibit Erk-1/2 activity. These results identify MKP-1 as essential for glucocorticoid-mediated control of Erk-1/2 activation and unravel a novel regulatory mechanism for this anti-inflammatory drug.

Animals↗
PubMed2001

Improving the detectability of focal liver lesions on T2-weighted MR images: ultrafast breath-hold or respiratory-triggered thin-section MRI?

The purpose of this study was to determine whether a respiratory-triggered (RT) T2-weighted turbo spin-echo (TSE) sequence with thin section can improve the detectability of focal liver lesions compared to a breath-hold (BH) T2-weighted TSE sequence. In 25 patients an RT TSE with 8-mm sections (8-TSE RT) and 5-mm sections (5-TSE RT) and a BH TSE sequence with 8-mm sections (8-TSE BH) were performed. Forty-one focal liver lesions (mean: 1.8 +/- 1.2 cm; 14 lesions < or =1 cm; 27 lesions >1 cm) were evaluated. The 5-TSE RT was significantly better in lesion detection compared to the 8-TSE BH sequence for all sizes of lesions (40/41 vs. 33/41; P = 0.014). For lesions >1 cm no relevant differences in the detection rate of the sequences were found (8-TSE RT, 26/27; 5-TSE RT, 26/27; 8-TSE BH, 25/27), for lesions < or =1 cm the 5-TSE RT provided significantly better sensitivity than the 8-TSE BH (14/14 vs. 8/14, P = 0.015). The results of this study suggest that lesion detection could be significantly improved by using an RT TSE sequence with thin sections compared with a BH TSE sequence.

Female↗
PubMed2001

Clinical and genetic analysis of Staphylococcus aureus nasal colonisation and exit-site infection in patients undergoing peritoneal dialysis.

Few data exist regarding the clonal identity of Staphylococcus aureus (SA) that colonises the nostrils and causes exit-site infections in peritoneal dialysis patients. Nasal and exit-site swabs were taken monthly from 41 patients undergoing peritoneal dialysis, and a genetic analysis of SA isolates was performed by pulsed-field-gel electrophoresis. When SA was identified at the exit-site, the clonal identity of nasal and exit-site isolates was demonstrated. In 50% of the SA carriers, nasal isolates were genetically constant over time; in the other 50% a change of colonising SA strains was observed. The risk of exit-site infection was identical in both groups.

Adult↗
PubMed2001

A 5-year follow-up on antibody response after diphtheria and tetanus vaccination in hemodialysis patients.

Chronic renal failure is associated with a T-cell-dependent immune defect. In the past, various studies have focused on the insufficient immune response to vaccination of hemodialysis patients. An impaired vaccination response rate has been reported for vaccines against hepatitis B, influenza, tetanus, diphtheria, and others. However, no data exist on the long-term success of vaccination against tetanus and diphtheria in these patients. The aim of the present study is to investigate seroresponse to tetanus and diphtheria vaccination over a 5-year period. Antibody levels were determined by enzyme immunoassay. Antidiphtheria antibody levels of 31 hemodialysis patients were determined 5 years after vaccination. After 5 years, 10 of 31 patients (32%) had a protective antibody level against diphtheria (>/=0.1 IU/mL), whereas 12 months after vaccination, 26 of 71 patients (37%) were protected. Also, mean antibody levels significantly decreased. Furthermore, antitetanus antibody levels of 21 patients simultaneously vaccinated against tetanus and diphtheria were investigated. After 5 years, 15 of 21 patients (71%) were protected compared with 46 of 71 patients (65%) in the hemodialysis collective studied after 12 months. In the interval between 1 and 5 years after vaccination, significantly more patients in the initial nonresponder group had died than in the responder group; therefore, the overall protection rate observed in vaccinated patients increased. Our results provide evidence that during a 5-year period, antibody persistence against tetanus toxoid is better than that against diphtheria toxoid. Therefore, detection of individual antibody concentrations may be indicated to decide on revaccination.

Antibodies, Bacterial↗
PubMed2001

[Incidence and significance of small focal liver lesions in MRI].

PURPOSE: Analysis of the frequency and significance of small focal liver lesions (< or = 2 cm) detected on MRI in the presence or absence of a history of malignancy. METHODS: 628 MRI examinations of the liver performed during 1994-1996 were evaluated. The inclusion criterion into the study was the detection of a focal liver lesion with a size < or = 2 cm. The frequency, the size, the diagnostic proof, and the differential diagnosis of the focal liver lesions were analysed with regard to the patients history of a known malignant tumor. RESULTS: Overall, 179 of the 628 patients (28.5%) had focal liver lesions < or = 2 cm (n = 338). 58.9% of the lesions could be classified based upon follow-up studies by ultrasound, CT or MRI, or by biopsy. The remaining 41.1% of the lesions could not be classified due to the absence of follow-up examinations. 57.3% of all proven lesions were benign and 42.7% were malignant. A history of a malignant tumor was present in 76.7% of all patients with small liver lesions; however, lesions were benign in these patients in 50.6% of the cases. In patients with no known history of a malignancy, 75% of the lesions were benign and 25% were malignant. However, these malignant lesions were in 10/11 cases hepatocellular carcinomas in patients with liver cirrhosis. CONCLUSION: Even in the presence of a history of a malignant tumor, about 50% of the detected small liver lesions on MRI are benign. In the absence of a tumor history the probability of a small malignant liver lesion is very low, if the patients does not have liver cirrhosis where small hepatocellular carcinomas can be present.

Biopsy↗