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Biomedical subjects

G Becker

Publications and source records attributed to G Becker.

At least 91 records · Page 5Linked to original sources
PubMed1999

[1H-MR spectroscopy in anorexia nervosa: reversible cerebral metabolic changes].

PURPOSE: By using localized 1H-MR spectroscopy in the brain of patients with anorexia nervosa we wanted to verify our preliminary results and to look for a reversibility of the metabolic changes under therapy. METHODS: In 22 patients and 17 healthy volunteers (11 follow-up examinations) single voxel 1H-MR spectroscopy (TE = 50 ms, TM = 30 ms, TR = 1500 ms, voxel (2 cm)3, acq.: 256) was used in two different localizations (thalamus and parieto-occipital region). The first examination of the patients was performed before therapy, the follow-up examination at the end of therapy. RESULTS: In both regions of the brain we found a statistically significant elevation of the Cho/Cr-ratio in comparison to normal controls. The follow-up examinations revealed reversibility of the metabolic changes under successful therapy. CONCLUSIONS: 1H-MR spectroscopy reveals metabolic changes in the brain of patients with anorexia nervosa, which are reversible under successful therapy. These metabolic changes can be conclusively explained using a biochemical model.

Adolescent↗
PubMed1999

Postoperative neuroimaging of high-grade gliomas: comparison of transcranial sonography, magnetic resonance imaging, and computed tomography.

BACKGROUND: A precise and comprehensive knowledge of tumor burden and its extent and growth pattern in the pre- and postsurgical states is required to optimize tumor therapy and to determine treatment success and failure. This prospective study compares the diagnostic potential of computed tomography (CT), magnetic resonance imaging (MRI), and transcranial sonography (TCS) in the postoperative follow-up of brain tumors. METHOD: Twenty-six patients with high-grade gliomas were included in the study. After tumor debulking, a total of 31 biopsy specimens were obtained from the resection margin in 21 patients and histological findings were compared with the findings of early postoperative TCS, CT, and MRI. Findings indicating residual tumor tissue were nonlinear contrast enhancement at the resection site revealed by CT or MRI or hyperechogenic lesions revealed by TCS. Follow-up examinations using all three imaging techniques were performed every 3 months. The end points of the follow-up were tumor recurrence as defined by CT and MRI, death, or severe clinical deterioration. RESULTS: On the basis of the above criteria, TCS identified residual tumor more often than did CT or MRI. In the group of 19 patients with histologically proven tumor remnants, residual tumor tissue was identified by TCS in all patients, whereas MRI and CT failed to show contrast enhancement in three and eight patients, respectively. However, the results of the TCS were false positive for one patient because of hemorrhage into the resection site. The average time to identification of tumor regrowth was 27 weeks using TCS, 29 weeks using CT, and 33 weeks using MRI. Only the differences between TCS and MRI reached statistical significance. For one patient, multicentric tumor recurrence was not detected using TCS. CONCLUSION: TCS may complement CT and MRI in the postoperative follow-up of patients with high-grade gliomas. Because none of these modalities alone is both sensitive and specific, an integrated analysis of imaging findings is recommended.

Adult↗
PubMed1999

Diagnosis of MCA-occlusion and monitoring of systemic thrombolytic therapy with contrast enhanced transcranial duplex-sonography.

A case of a successful systemic thrombolysis of an acute middle carotid artery occlusion is reported. The case underlines the role of contrast-enhanced transcranial color-coded duplex sonography as a noninvasive technique for rapid diagnosis of vessel occlusion in acute stroke. The diagnostic potential of transcranial color-coded duplex sonography for indication and monitoring of intravenous systemic thrombolytic therapy is demonstrated.

Acute Disease↗
PubMed1999

Diagnostic impact of cerebral transit time in the identification of microangiopathy in dementia: A transcranial ultrasound study.

BACKGROUND AND PURPOSE: The diagnosis and quantification of microangiopathy in dementia is difficult. The assessment of small-vessel disease requires expensive and sophisticated nuclear medicine techniques. This study was performed to identify microangiopathy related to the integrity of cerebral microcirculation by sonographic measurements (arteriovenous cerebral transit time [cTT]). METHODS: We performed transcranial color-coded duplex sonography in 40 patients with vascular dementia, 20 patients with Alzheimer's disease or Lewy body disease, and 25 age-matched controls. The clinical diagnosis was established by history of dementia and neuroimaging findings. Cognitive impairment was assessed by the Mini-Mental State Examination and Alzheimer's Disease Assessment Scale. cTT is defined as the time required by an ultrasound contrast agent to pass from a cerebral artery to a vein. This was measured by recording the power-Doppler intensity curves in the P2 segment of the posterior cerebral artery and the vein of Galen. Previous studies have shown a prolongation of cTT in patients with cerebral microangiopathy. RESULTS: cTT was substantially prolonged in patients with vascular dementia (5.8 seconds; 25th percentile 4.5; 75th percentile 7.5; U test, P<0.001) compared with controls (3.1 seconds; 2.3; 3.4) but not in patients with degenerative dementia (3.7 seconds; 3.7; 4.2). In patients with vascular dementia, cTT was significantly correlated with cognitive impairment. CONCLUSIONS: cTT may be useful tool to disclose small-vessel disease in demented patients. Examination is noninvasive and quickly performed. It may be also useful in follow-up examinations in patients undergoing therapy.

Aged↗
PubMed1999

Radiation therapy for intracranial germinoma: results of the German cooperative prospective trials MAKEI 83/86/89.

PURPOSE: A multicenter prospective trial was conducted (Maligue Keimzelltümoren [MAKEI] 83/86/89) to assess outcome in intracranial germinoma after treatment with radiotherapy alone at reduced doses. PATIENTS AND METHODS: Between 1983 and 1993, 60 patients with histologically (n = 58) or cytologically (n = 2) confirmed germinoma were enrolled onto the study. Patients received radiotherapy alone (craniospinal axis/local boost). In the MAKEI 83/86 study (involving 11 patients), the dose to the craniospinal axis was 36 Gy and the dose to the tumor region was 14 Gy. In the MAKEI 89 study (involving 49 patients), doses were 30 and 15 Gy, respectively. RESULTS: Median patient age was 13 years (range, 6 to 31 years). Complete remission was achieved in all patients. The estimated (Kaplan-Meier) 5-year relapse-free survival rate was 91.0% +/- 3.9% at a mean follow-up of 59.5 months (range, 3 to 180 months); the estimated overall survival rate was 93.7% +/- 3.6%. Relapse occurred in five patients 10 to 33 months (mean, 18.4 months) after diagnosis (one patient developed a spinal canal metastasis and underwent salvage radiotherapy and chemotherapy; four patients had metastases outside the CNS and underwent salvage chemotherapy alone). Four patients died: one died from disease, two died from therapy-related complications, and one committed suicide. Acute complications with long-lasting sequelae were tumor or surgery related (three cases of blindness, six of reduced vision, two of hemiparesis). Psychosocial development was normal in the majority of patients. CONCLUSION: Radiotherapy directed toward the craniospinal axis or tumor site alone at decreased dose levels is effective. To reduce the risk of late side effects, further attempts to decrease total doses are justified. In cases of recurrent disease, chemotherapy administered outside the CNS is the treatment of choice.

Adolescent↗
PubMed1999

[Risk to employees in garbage collection and transport from pathogen exposure].

In a current study funded by the Federal Institute of Occupational Safety and Hygiene the microbial exposure during waste collection and the health of waste collectors are being examined. The investigation of the exposure is carried out in standard experiments and in field studies. It should give information about the extent of emissions of bacteria and fungi spores und confounding factors. Medical examinations of waste collectors will show if there are special health risks attributable to waste collection.

Bacterial Infections↗
PubMed1998

[Hepatocellular carcinoma: npn-surgical treatment].

The therapeutic modalities in patients with hepatocellular carcinoma (HCC) depend on the number, size and location of the lesions as well as the stage of the underlying liver disease and the physical condition of the patients. In patients with small and solitary lesions resection, liver resection and in selected cases liver transplantation can be curative. In more advanced stages of the disease with larger or multiple lesions PEI and/or transarterial chemotherapy with or without embolisation (TACE or TAC) can slow the progression of the disease. In disseminated disease, a radio-therapeutic approach can be taken in selected cases. The therapeutic strategy in patients with HCCs has to be individualized, frequently using a combination of therapeutic modalities. Different from the earlier unfavourable prognosis, today for most HCC patients a therapeutic strategy can be offered that results in a prolongation of life and in some cases even cure.

Carcinoma, Hepatocellular↗
PubMed1998

Proton magnetic resonance spectroscopy in acute, juvenile anorexia nervosa.

Anorexia nervosa is usually associated with a shrinkage of the brain that is at least partially reversible with weight gain. The pathogenesis of this brain abnormality is unclear. The purpose of this study was to investigate potential alterations in localized proton magnetic resonance (1H MR) spectra of anorectic patients immediately after an interval of excessive weight loss. Twelve patients and seventeen control subjects were examined. Water suppressed 1H MR spectra were recorded from two voxels placed in the thalamus and in the parieto-occipital white matter. The spectra of ten patients could be evaluated. Comparing patients and control subjects, significantly higher signal intensity ratios of choline containing compounds (Cho) relative to total creatine (Cr) as well as significantly lower ratios of N-acetyl-aspartate (NAA) relative to Cho were found in the white matter region. We hypothesize that these results indicate an abnormal starvation, associated membrane turnover, which predominantly takes place in the white matter. No evidence for neuronal degeneration was found in the thalamus or in the white matter region.

Adolescent↗
PubMed1998

p16/MTS1 inactivation in ovarian carcinomas: high frequency of reduced protein expression associated with hyper-methylation or mutation in endometrioid and mucinous tumors.

Inactivation of the tumor-suppressor gene p16 (MTS1/ CDKN2/INK4a) has been described in various human malignancies. Although p16 deletion has been found in various ovarian tumor cell lines, p16 inactivation by homozygous deletion or mutation has been reported only sporadically in primary ovarian carcinomas. In a comprehensive study, we analyzed p16 protein expression by immuno-histochemistry (IHC) on paraffin sections of 94 primary ovarian carcinomas of different histological subtype. Loss of expression was detected in 19 primary tumors (20%), mainly mucinous and endometrioid carcinomas. To reveal the cause of suppressed expression, we performed (i) analysis of homozygous deletions by comparative PCR after micro-dissection, (ii) mutation analysis by single-strand conformation polymorphism analysis and subsequent direct sequencing and (iii) methylation-specific PCR to determine the methylation status of 5'-CpG islands. Loss of or weak p16 expression was caused by hyper-methylation (12/19 IHC-negative cases), somatic mutation (10 tumors) or homozygous deletion (1 case). Aberrant p 16 results by one of these methods were detected in 71-79% of endometrioid and mucinous, but in only 10% of serous-papillary, carcinomas. Our data suggest that p16 inactivation is a typical feature of certain subtypes of ovarian carcinoma.

Adenocarcinoma, Mucinous↗
PubMed1998

Imaging the pre- and postsynaptic side of striatal dopaminergic synapses in idiopathic cervical dystonia: a SPECT study using [123I] epidepride and [123I] beta-CIT.

There is increasing evidence that a dysfunction of the dopaminergic system may be involved in the pathogenesis of idiopathic dystonia. To visualize possible alterations of the pre- and postsynaptic side of striatal dopaminergic synapses, SPECT studies using the radiotracers [123I] epidepride and [123I] beta-CIT were performed in 10 patients with idiopathic cervical dystonia. Eleven age- and sex-matched subjects served as controls. [123I] Epidepride is a new highly affine marker of D2 receptors, and [123I] beta-CIT binds to dopamine transporters on dopaminergic nerve endings. [123I] Epidepride binding was significantly reduced in both striata of dystonia patients compared with controls (p < 0.05). In contrast, striatal [123I beta-CIT uptake did not differ from controls. We conclude that dopaminergic dysfunction in idiopathic focal dystonia mainly involves postsynaptic mechanisms and suggest a disturbance of the indirect pathway of the motor circuit resulting in a disinhibited thalamocortical stimulation.

Adult↗
PubMed1998

The disclosure decision: concerns and issues of parents of children conceived through donor insemination.

OBJECTIVE: The purpose of our study was to examine the disclosure decision by parents of children conceived by donor insemination. STUDY DESIGN: A qualitative component of a self-administered questionnaire mailed to 184 couples who had become parents by donor insemination encouraged respondents to volunteer their written comments, concerns, or opinions about their disclosure decision. RESULTS: A total of 70 men and 86 women submitted written comments indicating that 54% did not plan to disclose the donor insemination treatment (nondisclosers), 30% indicated they would (disclosers), and 16% remained undecided. The only significant relationship between the disclosure decision and expressed concern was with regard to confidentiality and honesty (chi2 = 99.9, p < 0.05). CONCLUSIONS: Whether parents viewed the disclosure issue as one of honesty (disclosers) or confidentiality (nondisclosers) was the major determinant in the decision of whether to tell children about their donor insemination origin. There was no association between disclosure status or gender and expressed concerns about parenting, children, or family relations.

Adult↗
PubMed1998

Pattern of graft- and host-specific MHC class II expression in long-term murine cardiac allografts: origin of inflammatory and vascular wall cells.

In solid-tissue allografts, donor vascular cells as well as recipient inflammatory cells can express MHC class II molecules. However, it is uncertain how much residual donor endothelium persists and to what extent donor versus recipient MHC class II expression can contribute to the ongoing immune response, especially in long-term grafts. To establish the origin of class-II-expressing cells in the allograft, we evaluated the expression of donor- or recipient-specific MHC class II molecules in murine cardiac allografts. Donor hearts from BALB/c (H-2d) mice were transplanted into C57BL/6 (B6, H-2b) recipients; B6 isografts served as controls. Untreated allografts ceased functioning at approximately 7 days with severe parenchymal rejection. Allografts from recipients treated with anti-CD4 and anti-CD8 MAbs after transplantation were explanted at 8 to 12 weeks and demonstrated intimal fibroproliferative lesions with a mild parenchymal mononuclear cell infiltrate. Class II expression in isografts was limited to epicardial macrophages. Both acutely rejecting and long-term allografts contained abundant macrophages expressing recipient class II molecules. Occasional cells (passenger leukocytes) in untreated, acutely rejecting allografts bore donor class II molecules; long-term allografts contained few such cells. In contrast, vascular endothelial and medial smooth muscle cells consistently expressed donor class II molecules. These results suggest that ongoing MHC class II expression in donor vascular cells, as well as in recipient macrophages, may contribute to sustained activation of host T cells with consequent release of cytokines that ultimately promote the development of graft arteriosclerosis.

Actins↗
PubMed1998

Interferon-gamma-secreting T-cell populations in rejecting murine cardiac allografts: assessment by flow cytometry.

Interplay between T-helper-1 (Th1) and T-helper-2 (Th2) cells is considered important in the development of acute allograft rejection and many other immune-mediated disease processes. Existing methods for evaluating expression of Th1 and Th2 cytokines, including reverse transcriptase polymerase chain reaction (RT-PCR), RNase protection assay (RPA), immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) all have limitations; alternate techniques to quantify cell populations expressing specific cytokine proteins, generate statistically analyzable data, and allow simultaneous identification of cytokine-secreting cell type are needed. To this end, we adapted a flow cytometric technique for intracellular cytokine immunofluorescence staining for use with cells isolated from solid tissue. To demonstrate the utility of the method, we determined the number of CD4+ and CD8+ cells secreting the prototypical Th1 and Th2 cytokines, interferon (IFN)-gamma, and interleukin (IL)-4 in acutely rejecting murine cardiac allografts. We also measured the cytokine production via ELISA, RPA, and semiquantitative competitive RT-PCR. The number of CD4+ cells producing IFN-gamma increased as rejection proceeded, in agreement with previous data; we detected no IL-4 production at any time, although relatively low numbers of IL-10-producing cells were identified. In addition, a high percentage of CD8+ cells, which outnumber CD4+ cells at day 6 after transplant, also produce IFN-gamma, suggesting that cytotoxic lymphocytes contribute significantly to the local cytokine milieu. This new application of intracellular cytokine staining provides a powerful methodology for studying transplantation immunology. The method may also be easily adapted to the study of other immune-mediated processes.

Animals↗
PubMed1998

Do urinary tract infections trigger chronic kidney transplant rejection in man?

PURPOSE: Urinary tract infections are frequent after kidney transplantation but little is known about the impact on long-term survival. As chronic rejection is the major cause of graft loss in the long term, we retrospectively analyzed the role of urinary tract infections in this process. MATERIALS AND METHODS: We included in the study all adult patients who received kidney transplants at our unit between 1972 and 1991, which ensured followup of at least 5 years, and we focused on the relationship between urinary tract infections and the incidence of chronic rejection episodes. To analyze the influence of urinary tract infections on chronic rejection patients were separated into those in whom biopsy proved chronic rejection developed within the first 5 years after transplantation (chronic rejection group 225) and those without apparent signs of chronic rejection during that period (control group 351). The correlation between urinary tract infections per year and the incidence of chronic rejection was analyzed. RESULTS: Patients with chronic rejection had more urinary tract infections per year than controls. In the first year after transplantation both groups had the highest incidence of urinary tract infections but thereafter the rate of urinary tract infections per year declined. However, the incidence consistently remained higher in the chronic rejection group. This difference reached significance by year 3 after transplantation. Furthermore, a high rate of urinary tract infections correlated with an early onset of chronic rejection. CONCLUSIONS: Urinary tract infections are an important risk factor for the onset of chronic rejection, and early and intense treatment is critical.

Adult↗
PubMed1998

Differentiation between intracerebral hemorrhage and ischemic stroke by transcranial color-coded duplex-sonography.

BACKGROUND AND PURPOSE: The differential diagnosis of intracerebral hemorrhage versus ischemic stroke has critical implications for stroke management. Transcranial color-coded duplex sonography (TCCS) has been shown to identify intracerebral hemorrhages and intracerebral vessel occlusions. We conducted this study to evaluate the sensitivity and specificity of TCCS in this differential diagnosis and in the detection of stroke complications. METHODS: One hundred fifty-one patients (58 women, 93 men; mean age, 65.6 years [range, 32 to 89 years] ) with acute hemiparesis were enrolled in this prospective study. On admission all patients had a complete neurological examination. A cranial CT scan and a sonographic examination of the brain parenchyma and all extracranial and intracranial cerebral arteries were conducted. The sonographer was blinded for the radiological findings. RESULTS: According to CT criteria, 60 patients had an intracerebral hemorrhage and 67 patients had an ischemic stroke, and in 24 patients CT findings were inconclusive, showing neither bleeding nor an ischemic stroke. On sonographic examination, 18 patients (12%) had no sufficient acoustic bone window. Of the remaining 133 patients, 126 (95%) were diagnosed correctly by sonography in agreement with CT. Sonography missed 3 atypical bleedings (2 with upper parietal location). In 4 patients without bleeding, an intracerebral hemorrhage was suspected by TCCS because of increased white matter echo density due to microangiopathy. Stroke complications depicted by CT (disturbance of cerebrospinal fluid circulation, hemorrhagic transformation, midline shift, ventricular bleeding) (n=54) were correctly shown by TCCS in 45 patients (83%). No complication was missed that would have required further treatment. CONCLUSIONS: In comparison to the "gold standard" of CT, TCCS identified stroke complications and differentiated between intracerebral hemorrhage and ischemic stroke with reasonable sensitivity. Thus, if CT is not readily available, TCCS may complement clinical examination in patients with acute stroke. In addition, it may also be useful in detecting stroke complications in the follow-up of stroke patients.

Adult↗