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Biomedical subjects

S Janssen

Publications and source records attributed to S Janssen.

At least 37 records · Page 2Linked to original sources
PubMed1996

Molecular epidemiology of apparent outbreak of invasive aspergillosis in a hematology ward.

During a 2-month period, five patients suffering from invasive infections caused by Aspergillus flavus or Aspergillus fumigatus were identified in the Hematology Department of the University Hospital Dijkzigt (Rotterdam, The Netherlands). To study the epidemiological aspects of invasive aspergillosis, strains from these patients and from the hospital environment, isolated during extensive microbiological screening, were subjected to genotyping. A novel DNA extraction technique, involving freezing, grinding, and direct lysis in guanidium isothiocyanate-containing buffers of mycelial material, was applied. DNA isolation was followed by typing by random amplification of polymorphic DNA (RAPD) analysis. This showed that strains isolated from all patients infected with the same fungal species were genotypically distinct, thus providing evidence against the possibility of an ongoing, single-source nosocomial outbreak. Strains could also be differentiated from strains of geographically diverse origins. However, an A. flavus strain from one of the patients was also frequently encountered in the hospital environment. As all environmental strains were collected after this patient had been diagnosed with invasive disease, the epidemiological value of this observation could not be ascertained. Intensive investigations showed no single source of A. flavus or other aspergilli. RAPD genotyping proved that the outbreak of invasive aspergillosis in the hematology ward consisted of a series of unrelated events and was not due to a common source within the hospital. RAPD fingerprinting of aspergilli may greatly facilitate future investigations of the epidemiology of invasive disease caused by these pathogens.

Adult↗
PubMed1994

A slow release formulation for recombinant bovine interferon alpha I-1.

Recombinant bovine interferon-alpha I1 (rBoIFN-alpha) has known antiviral and immunomodulatory effects which have been exploited to reduce clinical disease in a number of clinical situations including bovine respiratory diseases. A slow release rBoIFN-alpha formulation may be of value to reduce bovine respiratory disease under field conditions by extending the period of protection, and hence improving the prophylactic benefits of rBoIFN-alpha. In this report, we describe a formulation of rBoIFN-alpha in sesame oil containing calcium stearate which can successfully sustain the release of rBoIFN-alpha over an 8-day period. Recombinant bovine IFN-alpha could be measured in serum for 8 days following treatment with an initial burst of release 6 h after injection. After a single subcutaneous depot injection of 50 mg and 100 mg of rBoIFN-alpha, initial serum levels reached 12-15 ng/ml and 25 ng/ml respectively. Correlating with this burst of release, there was a decrease in the number of circulating CD4-CD8- gamma delta+ T lymphocytes, and a slight neutropenia. No alterations in other cell phenotypes tested (CD4, CD8, CD2, CD6, B cells, monocytes or MHC class II) were observed, nor were there changes in lymphokine activated killer (LAK), natural killer (NK) cell activity, or oxygen radical formation (assessed by reduction of nitroblue tetrazolium). However, despite the rapid and short-lived burst of rBoIFN-alpha, levels of 2-5 oligoadenylate (2-5 A) synthetase remained elevated for 8 days. The sustained increase of 2-5 A synthetase was not due to the high initial dose released during the burst 6-12 h after injection, since injection of a bioavailable equivalent dose of interferon induced a significant rise in 2-5 A synthetase activity for 4 days only. As 2-5 A synthetase is known to be a correlate of antiviral activity, we propose that this formulation of rBoIFN-alpha may be one approach to increase the window of protection, leading to more effective prevention of bovine respiratory disease.

2',5'-Oligoadenylate Synthetase↗
PubMed1994

The UV action spectra for the clone-forming ability of cultured human melanocytes and keratinocytes.

Melanocytes (skin type 2) and keratinocytes were irradiated with UV light of 254, 297, 302, 312 and 365 nm and the survival was measured. Clone-forming ability was chosen as the parameter for cell survival. Melanocytes were found to be less sensitive to UV light than keratinocytes (a difference of a factor 1.22-1.92 for the UV-C and UV-B wavelengths (254, 297, 301 and 312 nm) and a factor 6.71 for the UV-A wavelength (365 nm). Because melanin does not appear to protect against the induction of pyrimidine dimers the difference between melanocytes and keratinocytes in the UV-C and UV-B region could not be explained by the presence of melanin in the melanocytes. The relatively small difference can be explained by the longer cell cycle of melanocytes, which provides more time for the melanocytes to repair UV damage. In the UV-A region the difference between melanocytes and keratinocytes was much larger, suggesting that besides the longer cell cycle some additional factors must be involved in protection against UV-A light.

Cell Survival↗
PubMed1992

Amyloid cardiomyopathy in systemic non-hereditary amyloidosis. Clinical, echocardiographic and electrocardiographic findings in 30 patients with AA and 24 patients with AL amyloidosis.

To underline the role of echocardiography in the detection of cardiac involvement in patients with amyloidosis, physical examination, echocardiography and electrocardiography were performed in 30 patients with AA amyloidosis (amyloid protein A, associated with chronic inflammatory disease, usually without cardiomyopathy) and 24 patients with AL amyloidosis (the immunoglobulin light chain derived type, often associated with cardiomyopathy). All patients had histological confirmation of amyloidosis by rectal or subcutaneous abdominal fat biopsy. The combination of increased thickness of the left ventricular posterior wall and interventricular septum with a low voltage electrocardiographic pattern is highly specific for cardiac amyloidosis and was found in 3/30 (10%) of the AA patients and in 13/24 (54%) of the AL patients. The echocardiographic abnormalities were strongly related to the degree of clinical heart disease, showing mildly or moderately increased wall thickness in the early asymptomatic phase or severe thickening and hypokinesia of the left ventricular posterior wall and interventricular septum in clinically apparent cardiac dysfunction. Echocardiography appears to be a sensitive test for the detection of cardiac involvement in amyloidosis, in symptomatic as well as asymptomatic patients.

Adult↗
PubMed1992

Biocompatibility and IOL.

"Biocompatibility": meaning, investigation and importance for intra-ocular lenses. As PMMA isn't as biocompatible as initially thought, one searches for other materials on the one hand and tries to modify the surface of the PMMA on the other. For the latter only the HSM (heparin surface modifying) technique is currently used.

Adsorption↗
PubMed1992

The use of the first locally manufactured epikeratolens for keratoconus in Leuven.

We adapted a lathe to the production of keratolenses. A cornea is mounted on a chuck and frozen at minus 40 degrees C. Hereafter we can cut the desired posterior radius and diameter. The first plano keratolens produced was used to correct keratoconus. The favourable result encouraged us to manufacture keratolenses for the correction of refractive errors.

Adult↗
PubMed1990

Soft-tissue uptake of 99mTc-diphosphonate and 99mTc-pyrophosphate in amyloidosis.

This study describes the results of scintigraphy with 99mTc-labeled methylene-diphosphonate (99mTc-MDP) and pyrophosphate (99mTc-PYP) as a noninvasive test for the distribution of organ involvement in five different types of amyloidosis. Scintigraphy with 99mTc-labeled phosphates appeared to be a sensitive noninvasive screening test for the extent and the distribution of organ involvement in systemic AA and systemic AL amyloidosis as well as in local bronchial amyloid, local dermal amyloid, and familial amyloidotic polyneuropathy. Echocardiography, however, was more sensitive for demonstrating cardiac involvement in systemic amyloidosis than 99mTc-MDP or 99mTc-PYP scintigraphy. 99mTc-MDP images showed a better contrast than 99mTc-PYP images, although there was no difference in the extent or the intensity of soft-tissue uptake.

Adult↗
PubMed1990

HLA class I-, complement C4- and 21-hydroxylase probes in the genetic analysis of 21-hydroxylase deficiency.

In order to develop an optimal strategy for the prenatal diagnosis of steroid 21-hydroxylase (EC 1.14.99.10) deficiency, we investigated 16 affected families with salt wasting syndrome. Genomic DNA derived from peripheral white blood cells was digested with 6 different restriction enzymes. Hybridisation was carried out with DNA-probes of the HLA class I region, the 21-hydroxylase- and the complement C4 genes. All the families were informative in at least three different loci. Twelve out of the 16 families were informative by neutral polymorphisms or disease related variants of the 21-hydroxylase gene or the adjoining C4 locus. The reliability of prediction in these cases exceeded 99%. The remaining 4 families were informative only in the HLA class I region, tantamount to a reliability of prediction of about 98%. In none of the cases did we have to fall back on semiquantitative gene dose assessments. We further describe new polymorphisms in the 21-hydroxylase region for the enzyme Pvu II and EcoR V.

Adolescent↗
PubMed1990

Amyloid tumour resected by laser therapy.

We report a patient presenting with dyspnoea, cough and fever with a middle lobe atelectasis. Amyloid deposits in the bronchial wall caused almost complete obstruction of the middle lobe bronchus. The patient was treated with neodymium yttrium aluminium garnet (NdYAG) laser photoresection resulting in complete clearance of the middle lobe bronchus. Laser therapy has to be considered as first-line therapy for patients with endobronchial amyloidosis.

Adult↗
PubMed1989

Interleukin-2 with or without LAK cells in metastatic renal cell carcinoma: a report of a European multicentre study.

Between October 1987 and November 1988, 95 European patients with metastatic renal cell carcinoma have been treated with recombinant interleukin-2 (rIL-2) (EuroCetus) at 18 X 10(6) IU/m2/day (equivalent to 3 X 10(6) Cetus Units/m2/day) according to the West schedule in two trials. 1. Forty-two patients received rIL-2 alone. Median time between initial diagnosis and metastases was three months. Eighty-one percent of the patients had at least two involved sites at inclusion and 86% underwent prior nephrectomy. Twenty-seven patients (64%) received two successive courses. Over 80% of the planned dose was administered in 69% and 44% of patients during courses 1 and 2, respectively. Fever, hypotension, weight gain, rise in creatinine level, hepatic disturbances, anaemia and thrombocytopenia were commonly observed but resolved promptly after completion of therapy. No toxic death was recorded. Two (6%) complete responses (CR), four (13%) partial responses (PR), four stable diseases (SD) and 22 progressive diseases (PD) were observed. The response rate is 6/32 (19%); the median progression-free survival time is not reached at 218+ days (92-394). 2. Fifty-three patients received rIL-2 with lymphokine-activated killer (LAK) cells. Median time from primary diagnosis to metastases was three months. Eighty-five percent of patients had at least two involved sites though 73% had previously undergone nephrectomy. Forty patients (75%) received two successive induction courses. Most patients, i.e. respectively, 77% and 60%, were given at least 80% of the planned dose during courses 1 and 2. Median numbers of LAK cells infused were 13.1 and 11.6 X 10(9) nucleated cells per course, respectively. Toxicity was not different from that described above; no toxic death occurred; five CR (10%), nine PR (18%), 11 SD and 26 PD were observed. The response rate is 14/51 (27%) and the median progression-free survival time is not reached at 7.2+ months (3-13.1). In conclusion, rIL-2, with or without LAK cells, is obviously active on metastatic renal cell carcinoma. The difference in response rate between the two trials is not statistically significant but has to be paralleled with the difference in dose received by the patients rather than with the addition of a cellular therapy. Toxicity was always manageable and reversible. The association of rIL-2 with other lymphokines should represent a major issue to improve the response rate and will be considered in further European studies.

Carcinoma, Renal Cell↗
PubMed1988

AA amyloidosis associated with systemic lupus erythematosus.

A 54-year-old female with a 23-year history of systemic lupus erythematosus was admitted because of loss of renal function and nephrotic syndrome. Renal biopsy showed deposition of AA amyloid as demonstrated by Congo red staining and reactivity with protein AA-specific antibodies. Immune deposits were present in the mesangium and the glomerular basement membrane, but histopathological changes consistent with lupus nephritis were not detected. The rare association of systemic lupus erythematosus and amyloidosis is discussed in view of the characteristics of the acute phase reaction in systemic lupus erythematosus.

Amyloidosis↗
PubMed1988

Impairment of organ function after oral ingestion of refined petrol.

After oral ingestion of 600 ml of refined petrol a 23-year-old male developed multiple organ failure. Acute renal insufficiency due to nephrotoxic tubular necrosis requiring hemodialysis was a major manifestation. Moreover, respiratory failure, seizures, hemolysis, disseminated intravascular coagulation, liver damage and erosions of mucous membranes occurred. The patient subsequently recovered completely. In spite of the poor absorption from the gastrointestinal tract and the high first-pass effect in the liver, massive petrol intoxication may lead to reversible multisystemic lesions.

Acute Kidney Injury↗