PubMed Health⌕ Search

Biomedical subjects

G Janssen

Publications and source records attributed to G Janssen.

At least 19 recordsLinked to original sources
PubMed2004

Oncological management of pediatric cancer patients belonging to Jehovah's Witnesses: a two-institutional experience report.

OBJECTIVES: Aim of this study was to analyze the feasibility of oncological treatment in pediatric patients belonging to Jehovah's Witnesses and to describe the changing policy in performing transfusions and supportive care measures at two German pediatric cancer institutions. PATIENTS AND METHODS: Over a period of 16 years 21 treatments according to the current cooperative protocols were performed in 14 children of Jehovah's Witnesses. Various hematological supportive care measures such as supplementation with iron, human erythropoietin, interleukin 11, granulocyte colony-stimulating factor and autologous or allogeneic stem cell rescue had been applied. For comparison matched pairs treated in our hospitals not belonging to Jehovah's Witnesses and 50 pediatric and adult oncological patients belonging to Jehovah's Witnesses reviewed from the international literature were analyzed with respect to transfusions and outcome. RESULTS: So far, 9 of 14 children are surviving 16-195 months (median 26 months). During the primary therapy they received markedly less transfusions than the control cohort (-39,1% red blood cell transfusions and -37,5% platelet transfusions). The review of 50 reported cases showed that oncological therapy can also be successfully performed with a restricted transfusion regimen in children and particularly in adults. CONCLUSION: Pediatric cancer patients belonging to Jehovah's Witnesses can be treated similarly to other patients. A restrictive transfusion policy and the broad application of hematopoietic supportive care measures may reduce transfusions. This treatment policy and a continuous collaboration with the Hospital Liaison Committee for Jehovah's Witnesses appears to create an oncological treatment situation with a high compliance of patients and parents where court orders may not be necessary.

Blood Loss, Surgical↗
PubMed2002

Improvement of quality of life in women using a low-dose desogestrel-containing contraceptive: results of an observational clinical evaluation.

OBJECTIVE: To assess the influence of an oral contraceptive (OC) containing 20 microg ethinylestradiol and 150 microg desogestrel on quality of life and subjective symptoms. METHODS: In this multicenter observational evaluation performed in Germany, 3679 first-time OC users were included. They were treated by 623 physicians. The women completed quality of life questionnaires (Q-LES-Q) at baseline and after three treatment cycles. RESULTS: The mean age of users (+/- SD) was 22.5 +/- 7.1 years, with 47% of the women aged between 15 and 20 years. Half of the women reported skin problems at inclusion and, of these, 36% reported disappearance of the problems after three treatment cycles. Most women suffering from subjective symptoms (headache, nausea, nervousness, breast tenderness and depressive moods) at baseline reported improvements (57-71%) in their symptoms after using the OC for three cycles. Adverse events were reported by 4% of users; the most frequently reported were bleeding irregularities (1.7%). The total quality-of-life score and all its 13 individual items improved significantly (p < 0.0001), with the largest improvements in sex life and mood. Almost all (94%) women were either very satisfied or satisfied with the medication. CONCLUSION: The OC containing ethinylestradiol and desogestrel significantly improved the quality of life and subjective symptoms. The OC was well tolerated by first-time users.

Adolescent↗
PubMed2001

Smooth muscle cell changes during flow-related remodeling of rat mesenteric resistance arteries.

To obtain information on the molecular and cellular mechanisms of flow-induced arterial remodeling, we analyzed the morphology and smooth muscle cell (SMC) characteristics in rat mesenteric resistance arteries after interventions that decreased and increased flow. Juvenile male Wistar Kyoto rats were subjected to surgery that, compared with control arteries, provided arteries with chronic low flow and chronic high flow. Low flow resulted in a decreased passive lumen diameter, hypotrophy of the artery wall, and both loss and decreased size of SMCs. Time course studies, with intervention length ranging from 2 to 32 days of altered blood flow, showed that the narrowing of the lumen diameter in low-flow arteries appeared within 2 days and that an early dedifferentiation of SMC phenotype was indicated by markedly reduced levels of desmin mRNA. High flow resulted in an increased passive lumen diameter and in hypertrophy of the artery wall. The hypertrophy resulted from SMC proliferation because SMC number, measured by the 3D-dissector technique, was increased and immunohistochemical assessment of proliferating cell nuclear antigen also showed an increase. The widening of high-flow arteries required 16 days to become established, at which time desmin mRNA was reduced. This time was also required to establish changed wall mass in both low-flow and high-flow arteries. Apoptotic cells detected by TdT-mediated dUTP-biotin nick end labeling staining were mainly located in the medial layer, and evaluation of DNA fragmentation indicated that increased apoptosis occurred in both low flow and high flow. This study shows for the first time direct evidence that reduced and elevated blood flow in resistance arteries produce, respectively, decrease and increase in SMC number, with dedifferentiation of the SMCs in both cases.

Animals↗
PubMed2001

Simultaneous A8344G heteroplasmy and mitochondrial DNA copy number quantification in myoclonus epilepsy and ragged-red fibers (MERRF) syndrome by a multiplex molecular beacon based real-time fluorescence PCR.

The association of a particular mitochondrial DNA (mtDNA) mutation with different clinical phenotypes is a well-known feature of mitochondrial diseases. A simple genotype-phenotype correlation has not been found between mutation load and disease expression. Tissue and intercellular mosaicism as well as mtDNA copy number are thought to be responsible for the different clinical phenotypes. As disease expression of mitochondrial tRNA mutations is mostly in postmitotic tissues, studies to elucidate disease mechanisms need to be performed on patient material. Heteroplasmy quantitation and copy number estimation using small patient biopsy samples has not been reported before, mainly due to technical restrictions. In order to resolve this problem, we have developed a robust assay that utilizes Molecular Beacons to accurately quantify heteroplasmy levels and determine mtDNA copy number in small samples carrying the A8344G tRNA(Lys) mutation. It provides the methodological basis to investigate the role of heteroplasmy and mtDNA copy number in determining the clinical phenotypes.

Cell Line↗
PubMed2001

Glycosylated vs non-glycosylated granulocyte colony-stimulating factor (G-CSF)--results of a prospective randomised monocentre study.

The discovery of the haematopoietic growth factor granulocyte colony-stimulating factor (G-CSF) has reduced infection-related morbidity in cancer patients by alleviating post-chemotherapy neutropenia. Two formulations of recombinant human (rh) G-CSF, one glycosylated and one non-glycosylated, are available. The glycosylated form, lenograstim, possesses at least 25% greater bioactivity in vitro. Some comparative studies into the preparation's potential to mobilise haematopoietic stem cells suggest a similar advantage. In the light of the great clinical importance of G-CSF, we have performed the first prospective, randomised, crossover study on children with chemotherapy-induced neutropenia. G-CSF (250 microg/m(2)) was started 1 day after the chemotherapy block, and was administered until a WBC >1500/microl was achieved on 3 successive days. Thirty-three G-CSF cycles from 11 patients (16 lenograstim, 17 filgrastim) were studied. They were investigated for duration of very severe (WBC <500/microl, 9 vs 9.5 days, lenograstim vs filgrastim, median) and severe leukopenia (WBC <1000/microl, 11 vs 11 days), infections (CRP >5 mg/dl, 5 vs 5.5 days), infection-related hospital stay (11 vs 9 days) and antibiotic treatment (9 vs 9 days). Statistical evaluation by paired analysis could not detect any difference between treatment groups; the median difference for all end-points was zero. In summary, at least at 250 microg/m(2), in terms of their clinical effect on neutropenia, the two G-CSF preparations appear to have identical activity.

Adolescent↗
PubMed2000

Interdisciplinary treatment in pediatric patients with malignant CNS tumors.

Despite sophisticated surgical methods only a few pediatric CNS tumors can be controlled by operation alone. Therefore multimodality treatment regimens are needed to improve quality of life and survival, which is most important in malignant neoplasms. Since 1998 we have treated 16 children with malignant CNS tumors. All 16 patients have been treated on an interdisciplinary basis and are therefore accompanied by a pediatric neurooncology group consisting of a neurosurgeon, pediatric oncologist, and radiotherapist. Depending on tumor histology, child's age, and extent of surgery, further adjuvant therapy is planned by this group. Newly diagnosed tumors are typically treated by a specific chemotherapy protocol according to a multi-institutional study. In recurrent tumors more individual treatment regimens are considered. Data concerning surgery, adjunctive treatment, complications, and outcome of all patients and four case reports are presented.

Adolescent↗
PubMed2000

[How to ablate: atrial tachycardia].

The ectopic atrial tachycardia is diagnosed in approx. 10 to 15% of supraventricular tachycardias. Since medical therapy is often shown to be ineffective, ablative procedures became especially important in this disease. Localization of the arrhythmia foci seems to be concentrated at anatomical preformations like the crista terminalis, right or left atrial appendage orifice or at the superior pulmonary veins. The P-wave vector in the surface ECG is predictive for focus localization: a positive or biphasic P-wave in a VL for right atrial foci, a positive P-wave in V1 for left atrial foci. Catheter ablation therapy is also shown to be very effective in this kind of supraventricular tachycardia.

Adolescent↗
PubMed2000

Multiple intracranial juvenile xanthogranulomas. Case report.

The authors report on an 11-year-old boy in whom proptosis of the eye caused by a benign intraosseous xanthofibroma of the left orbital wall became clinically apparent at the age of 4 years. Two years later he developed bilateral papilledema, at which time computerized tomography and magnetic resonance studies revealed multiple enhancing intracranial lesions. The largest mass was located in the left middle fossa; other lesions were located at the tentorium cerebelli, in both lateral ventricles, near the superior sagittal sinus, and extracranially near the left jugular vein. The mass in the left middle fossa was resected and diagnosed as juvenile xanthogranuloma (JXG). Thirty months later, the patient again became symptomatic, exhibiting behavioral abnormalities and a decrease in mental powers. At that time, the two remaining lesions in both lateral ventricles had grown enough to cause trapping of the temporal horns and raised intracranial pressure. These lesions were successively resected and histopathologically confirmed to be JXGs. However, resection of the second intraventricular lesion was complicated by postoperative bilateral amaurosis, presumably caused by postdecompression optic neuropathy. According to a review of the literature, fewer than 20 patients with JXG involving the central nervous system have been reported. The patient described in this report is the first in whom multiple intracranial JXGs developed in the absence of cutaneous manifestations. Although JXGs are biologically benign lesions, the treatment of patients with multifocal and/or progressive intracranial manifestations is problematic.

Brain Diseases↗
PubMed1999

A common mutation (epsilon1267delG) in congenital myasthenic patients of Gypsy ethnic origin.

OBJECTIVE: Mutation analysis of the acetylcholine receptor (AChR) epsilon subunit gene in patients with sporadic or autosomal recessive congenital myasthenic syndromes (CMS). BACKGROUND: The nicotinic AChR of skeletal muscle is a neurotransmitter-gated ion channel that mediates synaptic transmission at the vertebrate neuromuscular junction. Mutations in its gene may cause congenital myasthenic syndromes. A recently described mutation in exon 12 of the AChR epsilon subunit (epsilon1267delG) disrupts the cytoplasmic loop and the fourth transmembrane region (M4) of the AChR epsilon subunit. METHODS: Forty-three CMS patients from 35 nonrelated families were clinically classified as sporadic cases of CMS (group III according to European Neuromuscular Centre consensus) and were analyzed for epsilon1267delG by PCR amplification and sequence analysis. RESULTS: The authors report the complete genomic sequence and organization of the gene coding for the epsilon subunit of the human AChR (accession number AF105999). Homozygous epsilon1267delG was identified in 13 CMS patients from 11 independent families. All epsilon1267delG families were of Gypsy or southeastern European origin. Genotype analysis indicated that they derive from a common ancestor (founder) causing CMS in the southeastern European Gypsy population. Phenotype analysis revealed a uniform pattern of clinical features including bilateral ptosis and mild to moderate fatigable weakness of ocular, facial, bulbar, and limb muscles. CONCLUSIONS: The mutation epsilon1267delG might be frequent in European congenital myasthenic syndrome patients of Gypsy ethnic origin. In general, patients (epsilon1267delG) were characterized by the onset of symptoms in early infancy, the presence of ophthalmoparesis, positive response to anticholinesterase treatment, and the benign natural course of the disease.

Adolescent↗
PubMed1998

Combined therapy of medulloblastoma: review of 46 patients treated in a single institution.

Medulloblastoma is the most frequent malignant brain tumor in pediatric patients. Early treatment strategies, combining surgery and radiotherapy alone, resulted in survival rates of about 40% only. In the last 15 years, chemotherapy was used more frequently in combination with surgery and radiotherapy. The rationale was to increase the survival rate and to decrease radiation toxicity in young children. Forty-six patients younger than 16 years were treated between July 1977 and September 1995 in our institution (32 boys and 14 girls). Thirty-nine patients could be evaluated according to their postoperative treatment with regard to different protocols such as SIOP 1, SIOP 2, HDMTX/VCR, HIT protocol 89/91 and Carbo-PEI (one patient). In total, 21/39 patients are alive without evidence of disease (EFS 55 +/- 7%) with a follow-up of 26 to 210 months. Four children are lost to follow-up. Twelve patients died after relapse, 1 child died of MTX-induced brain atrophy, 1 patient developed a secondary malignancy (acute lymphoblastic leukemia) and died. The best results were seen in patients treated according to the HIT 89/91 protocol as first-line treatment (CR 9/10). The improvement in outcome of our patients with medulloblastoma in recent years suggests the benefit of intensified chemotherapy on survival. In addition, refinement in surgical and radiological treatment have certainly also contributed to the better results.

Adolescent↗
PubMed1998

Paraneoplastic limbic encephalitis in two teenage girls.

Paraneoplastic neurological disorders represent remote effects of cancer without invasion of tumor cells into the nervous system. Limbic encephalitis is a distinct entity mostly associated with small-cell carcinoma of the lung. We present the cases of two teenage girls who were admitted with clinical symptoms typical for limbic encephalitis. In the course of the disease, they exhibited characteristic evolutionary changes of brain MRI abnormalities. Onset of neurological symptoms and type of underlying neoplasia were different in both patients. In one girl the initial workup led to the diagnosis of nodular sclerosing Hodgkin disease which so far had not caused any symptoms besides the described neurological abnormalities. A diagnostic brain biopsy showed inflammatory changes and excluded invasion of malignant cells into the central nervous system. The other patient had been diagnosed with a small cell carcinoma of the ovary several months before neurological and brain MRI abnormalities were observed. This is the first report in which clinical picture, evolution of MRI abnormalities, and--in one case--characteristic neuropathological changes are suggestive of paraneoplastic limbic encephalitis in two adolescent girls.

Adolescent↗
PubMed1998

Complete remission of a diffuse pontine glioma.

A patient is described in whom a large diffuse glioma of the pons extending into the midbrain was diagnosed at the age of 2 years. Biopsy showed a fibrillary astrocytoma. After shunting of a hydrocephalus, the clinical symptoms abated without conventional therapy. Repeated MRI studies showed a continuous decrease of the tumour which was no longer visible when the patient was 6.6 years old. In reviews on spontaneous remissions of oncologic disorders we were unable to find a case of a biologically benign brain stem tumour. There is one isolated report on a similar case, though without histologic documentation.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Primitive neuroectodermal tumors of the cerebral hemispheres in two siblings with TP53 germline mutation.

AWe report on two siblings (brother and sister) who developed cerebral PNETs at the age of 5 years and 6 months, respectively. Both children were treated by operation followed by polychemotherapy. The brother also received cranio-spinal irradiation. Nevertheless, the children died about 12 months and 24 months post-operatively due to extensive cerebral tumor recurrences. Shortly after having lost both of her children, the mother developed an intra-abdominal tumor, which was resected and histologically diagnosed as ovarian carcinoma. Because of this unusual familial clustering of tumors and a positive history of brain tumors and other cancers in several maternal relatives, we analyzed DNA isolated from both PNETs and the ovarian carcinoma as well as constitutional (leukocyte) DNA from the whole family for mutation of the TP53 tumor suppressor gene. This analysis revealed that all tumors were homozygous for a missense mutation at codon 213 (CGA => TGG) resulting in an amino acid exchange from arginine to tryptophane. The same mutation was present in one TP53 allele in the constitutional DNA of the mother and the children, indicating that the mother had transmitted a TP53 germline mutation to both of her children. Analysis of loss of heterozygosity at microsatellite markers from 17p confirmed deletion of the paternal (wild-type) allele in both PNETs. Further investigation of the PNETs by comparative genomic hybridization revealed multiple chromosomal abnormalities. Interestingly, some genomic changes were common to both PNETs, while many others were not, a finding suggesting substantial genomic instability, probably as a consequence of p53 inactivation.

Adult↗
PubMed1998

Impedance rise, only clue to severe insulation damage in a transvenous single-lead AICD-system.

We report a case of severe insulation damage 10 months after implantation of a fourth-generation single-lead implantable cardioverter defibrillator in a 45-year-old patient with dilative cardiomyopathy. The measured impedance was > 2000 Ohm and decreased to < 100 Ohm after slight pressure was applied to the device. All other parameters including intracardiac ECGs and markers were normal. Despite this delicate finding operative exploration revealed severe insulation damage of the pace-sense arm of the plug and insulation loss proximal to the distal coil of the lead.

Cardiomyopathy, Dilated↗
PubMed1997

CNS late effects after ALL therapy in childhood. Part I: Neuroradiological findings in long-term survivors of childhood ALL--an evaluation of the interferences between morphology and neuropsychological performance. The German Late Effects Working Group.

The effect of cranial irradiation on possible therapy-induced morphological central nervous system (CNS) side effects of children cured from acute lymphoblastic leukemia (ALL) is controversially discussed. In a retrospective multicenter study, 118 former ALL patients in first continuous remission were investigated using cranial computerised tomography (CCT) or magnetic resonance imaging (MRI) scans to evaluate CNS related impairments. Corresponding to the different kinds of CNS prophylaxis, the patient sample was divided: group A (n = 39) receiving intrathecal methotrexate (ITMTX) and systemical medium-high-dose methotrexate (SMHDMTX), group B (n = 41) cranial irradiated (in mean 16.8 Gy) and administering ITMTX and SMHDMTX, group C (n = 38) irradiated (in mean 17.1 Gy) and getting ITMTX. Pathologic scans showed atrophy, leukoencephalopathy, calcifications or grey matter changes. These findings were compared with the neuropsychological test results. Abnormal MRI or CCI scans were found in 61/118 patients (51.7%). Fifteen belonged to group A (38.5%), 23 to B (56.1%) and 23 to C (60.5%). Patients with definite CNS changes show reduced neuropsychological test results. The prevalence of brain alterations seems to appear twice increased after lengthening the posttherapeutic interval in irradiated patients as in nonirradiated patients. Irradiated patients as an age younger than 2 years at diagnosis may show a lower prevalence for developing CNS alterations. CNS alterations are not sex-related. Children treated with cranial irradiation in combination with SMHDMTX and/or ITMTX were at greater risk of developing morphological brain alterations than patients with chemotherapy alone. These alterations are partly correlated with reduced neuropsychological performances and seem to stay with a longer posttherapeutic interval.

Adolescent↗
PubMed1997

alpha-Amino acids derived from ornithine as building blocks for peptide synthesis.

Recently great interest has arisen in the synthesis of combinatorial libraries, and this technology provides a significant partner to contemporary strategies in rational design and lead discovery. By simple combination of a given set of building blocks, high numbers of different molecules are produced simultaneously, increasing the possibility of discovery of a lead compound in a limited time. One direction of research in this field focuses on the synthesis of libraries composed of modified amino acids. Here, the synthesis and characteristics of some building blocks derived from ornithine are described. The synthesis is based on the acylation/sulfonation of the copper complex of ornithine by aroyl and arylsulfonyl chlorides exemplified by 2-thiophenecarbonyl chloride, p-toluenesulfonyl chloride and 8-quinolinesulfonyl chloride. To evaluate the potential use of these modified alpha-amino acids as component in an oligopeptide library, all three derivatives were incorporated in a hexapeptide with a random sequence using a standard coupling procedure (DIC/HOBt/DIEA). Depending upon the acidity of the amido hydrogen on the delta-nitrogen, competition between intramolecular cyclization and peptide bond formation was observed. The higher the acidity, the more pronounced is this side reaction. Coupling conditions for peptide formation were optimized so that the newly described amino acid based building blocks are suitable for incorporation into libraries consisting of unnatural amino acids. The outlined procedures open up a broad avenue of possibilities for creation of diversity into peptidic libraries.

Amino Acids↗
PubMed1997

At least nine cases of trisomy 11q23-->qter in one generation as a result of familial t(11;13) translocation.

Carriers of balanced reciprocal translocations may have a (high) risk for producing liveborn children with an unbalanced karyotype. We report a large family in which a translocation between the long arm of chromosome 11 and the short arm of chromosome 13 is segregating in at least five generations. During the course of our study 15 carriers of the balanced translocation were identified and nine cases of partial trisomy of the long arm of chromosome 11 were detected during pre- and postnatal studies. Several of the patients were thoroughly clinically examined and compared with similar published cases.

Adult↗