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Biomedical subjects

R Wieland

Publications and source records attributed to R Wieland.

17 recordsLinked to original sources
PubMed2006

[Retinoblastoma].

Retinoblastomas are the most frequent intraocular tumors in childhood. Untreated, the tumor is almost always fatal. Using a multidisciplinary approach combining the efforts of ophthalmologists, radiation oncologists, pediatric oncologists and geneticists a survival rate of more than 95% can be achieved. Molecular genetic research on the origin of retinoblastomas has substantially helped in our understanding of the origin of malignant tumors in general, as well as to the key role of the Rb-1 gene as a tumor suppressor.

Diagnosis, Differential↗
PubMed2005

Malignant meningioma as a second malignancy after therapy for acute lymphatic leukemia without cranial radiation.

RATIONALE: Meningiomas in the pediatric age group are very rare tumors, comprising about 1-4.2% of all primary pediatric intracranial tumors. CASE REPORT: We present a 17-year-old patient who suffered from an intraventricular malignant meningioma. At the age of 2 years, acute lymphatic leukemia (common ALL [cALL]) was diagnosed and successfully treated with chemotherapy. There was no cranial radiation therapy. In December 2001, 13 years after diagnosis of cALL, he complained of headache, vomiting, and walking difficulties. Magnetic resonance imaging showed an enhancing mass with cystic components in the trigone of the right lateral ventricle. The tumor was removed completely. Histological diagnosis revealed a malignant papillary meningioma. After removal of a recurrent meningioma 16 months later, he received local radiotherapy. CONCLUSION: Pathogenetic mechanisms, treatment options, and prognosis of meningiomas and secondary malignancies of this age group are discussed.

Adolescent↗
PubMed2005

Incidence of dysarthria in children with cerebellar tumors: a prospective study.

The present study investigated dysarthric symptoms in children with cerebellar tumors. Ten children with cerebellar tumors and 10 orthopedic control children were tested prior and one week after surgery. Clinical dysarthric symptoms were quantified in spontaneous speech. Syllable durations were analyzed in syllable repetition and sentence production tasks. Localization of the cerebellar lesions were defined after manual transfer from individual 2D-MR images onto 3D images of a spatially normalized healthy brain. Cerebellar children showed few and mild clinical signs of dysarthria. No difference was present in the sentence production task compared to controls. In five cerebellar children, syllables were prolonged in the syllable repetition task after surgery. Syllable duration normalized in an additional four-week session in all but one case. The MR-analysis showed that superior paravermal cerebellar areas likely involved in dysarthria in adults (paravermal lobules HVI, Crus I) were not significantly affected. In children, speech impairments appear to be rare after cerebellar surgery because tumors most commonly affect posterior-inferior and medial parts of the cerebellum while critical cerebellar regions are likely spared. The results suggest a similar localization of speech functions in the cerebellum in children and adults.

Acoustic Stimulation↗
PubMed2004

Do children with focal cerebellar lesions show deficits in shifting attention?

More recent findings suggest a possible role of the cerebellum in nonmotor functions. Disability of individuals with cerebellar damage in rapidly shifting attention is one frequently used example to support cerebellar involvement in mental skills. The original proposal was based on findings in five children with chronic surgical lesions of the cerebellum and a young adult with a degenerative disorder. The aim of the present study was to repeat Akshoomoff and Courchesne's initial findings in a larger group of children with focal cerebellar lesions. Ten children with cerebellar lesions and 10 age- and sex-matched controls were tested. Neocerebellar areas were affected in all children with cerebellar damage except one based on detailed analysis of MRI scans. Subjects had to perform a focus and a shift attention task. Two visual and two auditory stimuli were presented in a pseudorandom order. An ellipse and a high-pitched tone were presented less frequently than a circle and a low-pitched tone. Rare stimuli were presented at five different time intervals. In the focus tasks, subjects had to react to the same rare stimulus of one of the two modalities. In the shift task, subjects had to switch between the two rare stimuli. Motor deficits based on reaction times were small in cerebellar children compared with controls. The ability of target detection did not significantly differ in the children with cerebellar lesions compared with the control children in both the focus and the shift attention task. In particular, children with cerebellar damage showed no significant impairment in rapid (<2 s) shifts of attention. The present findings indicate that the cerebellum may be less critical in attention related processes than suggested previously.

Adolescent↗
PubMed2004

Differential diagnosis of cholestasis following allogeneic hematopoietic stem cell transplantation in children: the contribution of serum bile acid levels in relation to other liver function tests.

Hepatic complications associated with cholestasis occur frequently in hematopoietic stem cell transplant recipients. Since bile acid seems to be a sensitive indicator of beginning cholestasis, the authors monitored total serum bile acid levels in addition to the standard liver function tests in 23 recipients of allogeneic transplants between June 1999 and September 2000. The observations suggest that bile acid is an early and sensitive marker of hepatic GvHD but not as specific as bilirubin. For cholestasis in absence of hepatic GvHD bile acid seems to be more sensitive than bilirubin. Routinely monitoring of bile acid after hematopoietic stem cell transplantation is not indicated.

Adolescent↗
PubMed2003

High-dose chemotherapy with autologous stem cell rescue in children with retinoblastoma.

Children with metastatic retinoblastoma are considered to have a poor prognosis after conventional chemotherapy. We used high-dose chemotherapy (HDC) with peripheral hematopoietic stem cell transplantation in such patients in an attempt to improve their survival. Four patients with bone marrow metastases and one child with extraorbital disease were treated with HDC after achieving complete remission by enucleation and conventional chemotherapy. The child with extraorbital tumor was the only one to receive local irradiation. The conditioning regimen included thiotepa (900 mg/m(2)), etoposide (40 mg/kg) and carboplatin (1.5 g/m(2)) in four patients, and BCNU (300 mg/m(2)), cyclophosphamide (6.8 g/m(2)) and etoposide (1.6 g/m(2)) in one child. Hematologic recovery occurred without delay in all patients. The main toxicities were diarrhea, mucositis and infectious complications. No toxic deaths or any major late toxicities were observed. The child treated with the BCNU regimen developed a meningeal relapse 10 months after HDC, which was partially resected and treated with conventional chemotherapy, but not with radiotherapy. He is in complete remission (CR) 105 months off treatment. The other patients are in CCR for 107, 57, 9 and 8 months after HDC. HDC with thiotepa, etoposide and carboplatin may represent a curative option for children with extrabulbar or disseminated retinoblastoma responsive to chemotherapy. It may control occult CNS disease. The necessity to irradiate these children and the curative potential of this strategy for patients with bulky CNS disease remain to be determined.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

Thermochemotherapy in hereditary retinoblastoma.

BACKGROUND/AIM: The combination of chemotherapy and transpupillary thermotherapy, thermochemotherapy (TCT) has become an established part of the treatment plan in advanced retinoblastoma. The aim of this study was to identify safe indications, the complications as well as the limitations of this new treatment for retinoblastoma. METHODS: Tumour response and side effects of TCT with an indirect laser ophthalmoscope (spot size about 400 micro m) in 55 tumours of 26 children with bilateral retinoblastoma were analysed. Using the Reese-Ellsworth classification system, nine of 35 eyes were classified as type I, 13 eyes as type II, 10 eyes as type III, and three eyes as type V. The mean age of the children was 0.74 (SD 0.61) years. The mean tumour height was 3.5 (2.3) mm with a mean diameter of 6.1 (4.1) mm. Treatment parameters were 4.3 (1.6) (median 5) thermochemotherapy sessions with a mean energy of 539 (211) mW and a mean duration of 13.5 (5.6) minutes. Chemotherapy courses (vincristine, etoposide, and carboplatin) were repeated every 3 weeks. The mean follow up period was 1.25 (0.6) years. RESULTS: Local recurrence occurred in 21 tumours (38%), with a mean onset of 3.2 (2.9) months after TCT. The risk of tumour recurrence was correlated with tumour height. The recurrence rate was 17% for tumours with a height less than 2 mm, 37% for tumours with a height between 2 and 4 mm, and 63% for larger retinoblastomas. Multivariate analysis identified fish flesh regression after TCT (p = 0.0007) as the most important risk factor for tumour recurrence besides tumour height (p = 0.001) and the necessity of increased laser power during TCT sessions (p = 0.018). Complications during therapy included transient corneal opacification in two eyes (6%), focal iris atrophy (three eyes, 8.5%), peripheral lens opacity (two eyes, 6%), circumscribed transient retinal detachment (one eye, 3%) and diffuse choroidal atrophy (one eye, 3%). CONCLUSION: TCT using an indirect laser ophthalmoscope with a spot size of about 400 micro m was efficient for retinoblastoma with a tumour height less than 4 mm. In larger tumours, the recurrence rate was unacceptably high. Fish flesh regression after TCT correlates with a higher rate of local tumour recurrence. Treatment related complications occurred in less than 9% of the treated eyes.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

White matter disease in children treated for malignant brain tumors.

OBJECTS: The objects of the study reported were to recognize different patterns of white matter disease (WMD) in the follow-up of children after surgery, radiation and/or chemotherapy for malignant primary brain tumors and to evaluate statistical data on the incidence of WMD and various risk factors. METHODS: Magnetic resonance imaging (MRI) records were evaluated retrospectively in the routine follow-up (range 6 months to 15 years after surgery) of 44 children with malignant primary brain tumors treated with surgery and radiotherapy and/or chemotherapy. RESULTS: WMD was diagnosed in 28 children and subclassified into circumscribed white matter lesions (WML) and diffuse atrophy. WML were the most common finding ( n=13), followed by atrophy ( n=7) and the combination of both ( n=8). Statistical analysis revealed slightly more frequent atrophy in children younger than 5 years. WML could be linked with supratentorial location of the tumor, follow-up longer than 5 years, and the presence of a ventricular shunt. Intrathecal chemotherapy was also a factor, but because of the small sample size of the group this might not be valid. None of the children had neurological deficits attributed to these findings, but the impact on neuropsychological development was not determined.

Adolescent↗
PubMed2001

[Overweight and obesity in the Zurich canton. A LuftiBus study].

In this study the data from 30,598 subjects participating in the LuftiBus project during 1993-1998 were analyzed for the prevalence rates of overweight and obesity. 36.6% of men and 23.6% of the women in the total population were overweight (BMI 25.0-29.9 kg/m2) and 6.6% of the men as well as 7.5% of the women were obese (BMI > 30.0 kg/m2). At a younger age the women were in general lighter, however, with advancing age women became heavier than men. The prevalence data from this study are in quite good agreement with data from other Swiss epidemiologic studies as well international studies. The rather high prevalence rates of obesity show clearly that the problem of obesity can only be solved by preventive means.

Adult↗
PubMed2000

Proliferation-associated SNF2-like gene (PASG): a SNF2 family member altered in leukemia.

To identify genes involved in cell growth and/or apoptosis in leukemia, differential display was used to identify mRNAs that showed altered expression levels after cytokine withdrawal from the cytokine-dependent MO7e cell line. Sequence analysis of one transcript that showed a profound decrease in expression after cytokine withdrawal revealed it to be a member of the SNF2 family of chromatin remodeling ATPases. This cDNA had a 2514-nucleotide (838-amino acid) open reading frame and encoded an additional 230 amino acids at the NH2 terminus compared with the murine homologue, lsh, and the human counterpart, Hells. This gene locus has been designated SMARCA6 (SWI/SNF2-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 6). The highest levels of mRNA expression in humans are observed in proliferative tissues such as the thymus, testis, and bone marrow. Whereas cytokine withdrawal in MO7e cells leads to apoptosis and decreased mRNA expression, growth arrest without the induction of apoptosis of MO7e cells also leads to down-regulation of mRNA expression, suggesting an association with cell proliferation and not suppression of apoptosis. Nuclear localization of this SNF2-like putative helicase is dependent on a nuclear localization sequence located in the NH2-terminal region. Based on sequence homology to other SNF2-like helicases, the pattern of tissue expression, and the association of expression with cell proliferation, we refer to the protein product as proliferation-associated SNF2-like gene product [PASG (D. W. Lee et al., Blood, 94: 594a, 1999)]. Examination of acute myelogenous leukemia and acute lymphoblastic leukemia samples revealed a high frequency of a PASG transcript containing an in-frame 75-nucleotide deletion, which codes for a conserved motif known to be critical for the transactivation activity of a related yeast SWI/SNF polypeptide. These results extend our knowledge of this SNF2-like family member and suggest a role for PASG in leukemogenesis.

Alternative Splicing↗
PubMed1979

[Clinical and experimental evaluation of hydrophilic contact lenses for continuous-wear (author's transl)].

In a clinical and experimental study we tested a new contact lens for continuous-wear. The modified HEMA-lens ("Permalens", Global Vision Ltd, Southampton/GB; Cooper Laboratories, Düsseldorf) has a water content of 74% at pH 7.4. The oxygen transmissibility is, depending on the thickness of the lens, 38--67% of the oxygen in the air. In a first trial we had to eliminate 6 patients due to wrong fitting (much too steep) or dry eyes. After development of a new guide for selection of lens base curves 10 patients with monocular aphakia (10 eyes) and 12 patients with mild myopia (24 eyes) were fitted with the hydrophilic soft contact lens for permanent wear. From a total of 34 eyes in 11 cases (32%) the lenses were removed due to complications (1 conjunctivitis, 1 keratitis, 1 vascularization) or due to lack of cooperation. In 23 cases (68%) the continuous-war lenses were well tolerated without complications for 5 months. In a comparative study in vitro we tested the effect of the contact lens on the viability (swelling rate, intracellular membrane potential of the epithelium) of the isolated human cornea. A damaging effect of the lens on corneal function was not observed. The hydrophilic soft contact lens can be fitted for continuous-wear.

Adult↗
PubMed1978

Survey of mortality among employees engaged in the manufacture of styrene and polystyrene at the BASF Ludwigshafen works.

A mortality survey of 1,960 employees currently or previously exposed to styrene at work has shown that the observed number of deaths from cancer or other causes is no higher than the number expected in the German population or in a group of BASF employees. Analyses of deaths occurring after a minimum period of five years in groups exposed for different durations (5 years, 10 years, 15 years, more than 15 years) indicated no increase in mortality with exposure time. This latter observation also applied to malignant tumors; therefore it may be inferred that prolonged exposure to styrene is not a cancer hazard.

Adolescent↗
PubMedDate not supplied

Enrichment of residual tumor cells in bone marrow or peripheral blood cells in a neuroectodermal tumor model.

To enrich a small population of malignant cells contaminating human bone marrow or peripheral blood, a method of immunomagnetic depletion of the normal nucleated cells was developed. In a model using neuroectodermal cell lines, contaminations between 0.1% and 1.4% of tumor cells could be increased by a factor of 7.5 (median; range, 3.8 to 18.0; n = 10). Because incubation with antibodies is restricted to the magnetic beads in this method, the cell population after removal of the beads has not been incubated with antibodies. The risk of unspecific staining of the tumor cells during the enrichment procedure is minimal. This simple method is therefore well suited to the study of the characteristics of a minimal residual disease population.

Blood Cells↗