Echogenicity of the substantia nigra: association with increased iron content and marker for susceptibility to nigrostriatal injury

BACKGROUND: Patients with Parkinson disease characteristically exhibit an increased echogenicity of the substantia nigra (SN) on transcranial sonography, a new neuroimaging technique. The same echo feature of the SN can be identified in 9% of healthy adults. OBJECTIVE: To evaluate the relevance of the echogenic SN in healthy adults. DESIGN: In the first part of the study, 10 healthy subjects younger than 40 years with a distinct SN hyperechogenicity underwent extensive neurological, motor, neuropsychological, and fluorine 18-dopa positron emission tomographic ([18F]-dopa PET) examinations. Results were compared with those of 10 subjects with a low echogenic SN. In the second part of the study, the postmortem brains of 20 patients without extrapyramidal disorders during their lifetime were sonographically examined with a particular focus on SN echogenicity. Subsequently, one half of the brain was prepared for heavy metal analysis, the other for a histological examination. RESULTS: Healthy subjects with SN hyperechogenicity exhibited a significant reduction of the [18F]-dopa uptake, especially in the putamen (Wilcoxon matched pair test: left side, P =.006; right side, P =.009), whereas their neuropsychological and motor performance were normal. Postmortem studies showed that the echogenicity of the SN correlated with its iron content. CONCLUSIONS: Increased echogenicity of the SN, characteristically seen in Parkinson disease, is related to a functional impairment of the nigrostriatal system (even in young healthy adults) that can be revealed by [18F]-dopa PET studies. Substantia nigra hyperechogenicity is related to a higher tissue iron level, which is known to enhance the cells' generation of reactive oxygen specimens. Therefore, we hypothesize that transcranial sonography may identify a susceptibility marker for the development of nigral injury that can be detected early in life, prior to the onset of Parkinson disease.     

Long-term survival of glioblastoma multiforme: importance of histopathological reevaluation

The overall prognosis for patients with glioblastoma multiforme is extremely poor. However, a small proportion of patients enjoy prolonged survival. This study investigated retrospectively the extent to which erroneous histopathological classification may contribute to long-term survival of patients initially diagnosed with “glioblastoma multiforme”. We compared two age- and gender-matched patient groups with different postoperative time to tumor progression (TTP), defined as “short-term” for TTP of less than 6 months (n=54) and “long-term” for TTP of more than 12 months (n=52). Histological specimens of the corresponding tumors, all primarily diagnosed as glioblastome multiforme, were reevaluated according to the current World Health Organization (WHO) classification of central nervous system tumors, with the investigators being blinded to clinical outcome. Among the tumors from short-term TTP patients, one tumor (2%) was reclassified as anaplastic oligoastrocytoma (WHO grade III) while the remaining 53 were confirmed as glioblastoma multiforme. In contrast, 13 tumors (25%) from the long-term TTP patients were reclassified, mostly as anaplastic oligodendroglioma (WHO grade III; n=7) or anaplastic oligoastrocytoma (WHO grade III, n=2), respectively. In addition, three were reclassified as anaplastic astrocytoma (WHO grade III), and one was identified as anaplastic pilocytic astrocytoma (WHO grade III). Our data indicate that a sizable proportion of glioblastoma patients with long-term survival actually carry malignant gliomas with oligodendroglial features. The correct histopathological recognition of these tumors has not only progrostic but also therapeutic implications, since oligodendroglial tumors are more likely to respond favorably to chemotherapy. Received: 9 November 1999, Received in revised form: 13 January 2000, Accepted: 3 February 2000     

Erste Ergebnisse der neoadjuvanten simultanen Radiochemotherapie bei fortgeschrittenen Rektumkarzinomen

Hintergrund: Bei lokal weit fortgeschrittenen Rektumkarzinomen ist das Erreichen eine R0-Resektion schwierig. Muss jedoch makroskopisch oder mikroskopisch Tumorrest zurückgelassen werden, ist die Prognose der Patienten schlecht. In den Leitlinien empfiehlt die Deutsche Krebsgesellschaft deshalb bei Patienten mit T4-Tumoren eine präoperative simultane Radiochemotherapie. Patienten und Methodik: Vom 1.5.1997 bis 30.11.1999 wurde bei 22 Patienten eine neoadjuvante Radiochemotherapie durchgeführt. Appliziert wurde eine Dosis von 45 Gy zuzüglich eines Boostes von 5,4 Gy. In der ersten und fünften Bestrahlungswoche erhielten die Patienten an fünf aufeinander folgenden Tagen eine Dosis von täglich 1000 mg/m² 5-FU als intravenöse Dauerinfusion über 24 Stunden. Bei auftretender Kardiotoxizität wurde die Chemotherapie auf 5-FU-Bolusinfusion oder Ralitrexed umgestellt. Ergebnisse: 19/22 Patienten konnten einer Operation zugeführt werden. Bei 16/19 (84%) der operierten Patienten konnte eine R0-Resektion erreicht werden. Eine funktionserhaltende Behandlung war bei 9/19 (47%) Patienten möglich. Ein Downstaging um mindestens eine T-Kategorie wurde bei 12/19 (63%) Patienten erzielt. Bei einer medianen Nachbeobachtungszeit von 16 Monaten ist bisher kein lokales Rezidiv bei den operierten Patienten aufgetreten. Das progressionsfreie Überleben der operierten Patienten (R0/R1) beträgt nach zwei Jahren 62%, die Überlebensrate 89%, bezogen auf alle Patienten 76%. Schlussfolgerung: Die präoperative simultane Radiochemotherapie kann zu einer verbesserten Rate an R0-Resektionen und sphinktererhaltenden Eingriffen betragen. Purpose: In locally advanced rectal cancer tumor-negative margins often cannot be obtained by surgery alone. Nevertheless only patients with complete tumor resection can be cured. Due to the poor prognosis of patients with R1/R2 resection the "Deutsche Krebsgesellschaft" recommends concurrent preoperative radiochemotherapy for patients with locally advanced rectal cancer. Patients and Methods: Between May 1997 and November 1999 22 patients were treated with preoperative radiochemotherapy. A total dose of 45 Gy with a small-volume boost of 5.4 Gy was delivered in conventional fractionation (single dose 1,8 Gy). On days 1 to 5 and 29 to 33 patients received concurrently 5-fluorouracil (5-FU) as continuous infusion of 1,000 mg/m². If there was any sign of cardiac toxicity chemotherapy was changed to 5-FU/folinic acid or ralitrexed. Results: Surgery following radiochemotherapy was performed in 19/22 patients. Resections with negative margins were achieved in 16/19 (84%) patients. Sphincter-conserving surgery was possible in 9/19 (47%) patients. A downstaging of at least 1 T category was found in 12/19 (63%) patients. With a median follow-up of 16 months no locoregional recurrences occurred in patients who underwent surgery. Two-year disease-free survival of resected patients is 62%, 2-year overall survival is 89%, of the whole population 76%. Conclusion: Preoperative radiochemotherapy followed by surgery is able to achieve clear resection margins in more than 70% of patients with locally advanced rectal cancer and may improve the rate of sphincter-conserving surgery.     

Upregulation of Bcl-2 is involved in the mediation of chemotherapy resistance in human small cell lung cancer cell lines.

Chemotherapeutic drugs eliminate cancer cells by induction of apoptosis. Resistance to chemotherapy is partly due to a decreased apoptosis rate. Here we investigated resistance to anticancer drugs in 9 small cell lung cancer (SCLC) cell lines. Apoptosis was induced by cisplatin, doxorubicin and etoposide and was found to be independent of caspase-8 expression. Since caspase-8 is essential for signal transduction of death receptor-mediated apoptosis, all known death receptor systems are thus not required for drug-induced apoptosis in SCLC. Furthermore, we found that anticancer drugs could activate the mitochondrial pathway of apoptosis without involvement of upstream caspases. Finally, by culturing 3 sensitive cell lines in subtherapeutic concentrations of etoposide, resistant cells were generated that exhibit cross-resistance to cisplatin and doxorubicin. Drug resistance was paralleled by strong upregulation of Bcl-2, which diminished apoptosis by inhibiting the loss of the mitochondrial transmembrane potential and the release of cytochrome c. The role of bcl-2 in these processes was supported by bcl-2 transfection and antisense inhibition. These results indicate that Bcl-2 contributes to drug resistance in SCLC, a finding that has profound therapeutic implications.     

Serum levels of insulin-like growth factor-I,-II and insulin-like growth factor binding proteins-2 and-3 in children with acute lymphoblastic leukaemia

Abstract The insulin-like growth factor (IGF) signaling pathway may be of importance for the proliferation of different tumours (e.g. breast cancer and Wilms tumour). The bioavailability of both IGF-I and IGF-II is regulated by specific IGF-binding proteins (IGFBPs). IGFBP-2 is the predominant binding protein during fetal life, where it is expressed in most tissues. In contrast, postnatally it is mainly released by specific cell types (hepatocytes, astroglia, kidney cells, prostate cells) and a range of tumour cell lines. Furthermore, phytohaemagglutinin stimulated normal lymphoblasts and malignant lymphoblasts express IGFBP-2. In order to investigate the IGF regulatory pathway in leukaemia serum levels of IGF-I, IGF-II, IGFBP-2 and IGFBP-3 were determined in 28 leukaemic children. Whereas serum levels of IGF-I (mean/range: –2.7/–0.1 to –6.7 SDS), IGF-II (–3.6 SDS/–1.3 to –8.7) and IGFBP-3 (–2.0/+2.2 to –7.1 SDS) were significantly decreased comparable to levels in growth hormone deficiency, IGFBP-2 levels (+4.0/–0.45 to +7.4 SDS) were found to be markedly elevated and inversely correlated to IGF-I (r=–0.51,P=0.013). After haematological remission upon chemotherapy all four parameters had normalized in the 16 re-investigated children. Similar findings have been observed in one boy with a relapse including CNS leukaemia.Conclusion This study demonstrates that the proliferation of malignant lymphoblasts (at diagnosis vs treatment) occurs in the presence of decreased serum levels of IGF-I, IGF-II and IGFBP-3 and that diminished production of these peptides may contribute to impaired growth. It further indicates that serum levels of IGFBP-2 may be directly related to the proliferation of lymphoblasts.     

Der in vitro-Effekt der Hyperthermie auf den Einbau von Nucleinsäurevorläufern in Tumoren und normale Gewebe

Zusammenfassung Die Inkorporation von Präkursoren der Nucleinsäuresynthese wie ³H-Thymidin und ³H-Uridin in Zellen schnell proliferierender Gewebe kann in vitro durch Erhöhung der Temperatur im Inkubationsansatz auf 39,0° C und 41,0° C gehemmt werden. Tumorgewebe, embryonale Gewebe und regenerierende Leber verhalten sich dabei gleichartig. Die Hemmwirkung ist bei allen diesen Geweben proportional sowohl zum Ausmaß als auch zur Dauer der Temperaturerhöhung. Unsere Befunde sprechen außerdem für eine individuelle Wärmesensibilität der untersuchten Tumoren und der anderen rasch proliferierenden Gewebe. Die gleichzeitige Anwendung von Wärme und Bleomycin führt weder beim Jensen Sarkom noch beim Tumor GW-39 zu einem Additionseffekt. Dagegen zeigen Hydroxyharnstoff und Wärme gleichzeitig angewendet eine additive Hemmwirkung auf den ³H-Thymidineinbau in den Tumor GW-39.Da entsprechende Temperatureinflüsse bei ruhenden Geweben nicht nachzuweisen sind, scheint es sich bei der beobachteten Temperaturempfindlichkeit um eine Besonderheit proliferierender Zellsysteme zu handeln. Es ist daher zu klären, ob sie nur unter den Bedingungen des in vitro-Versuches zum Ausdruck kommt oder, ob sie als Indiz einer allgemeinen Thermosensibilität der Nucleinsäurebiosynthese bei schnell proliferierenden Zellverbänden angesehen werden muß.

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In vitro effect of hyperthermia on the incorporation rate of nucleic acid precursors in tumours and normal tissues

Summary The incorporation of precursors of the nucleic acid synthesis, such as ³H-thymidine and ³H-uridine, in cells of rapidly proliferating tissues can be inhibited in vitro by increasing the temperature in the early stages of incubation from 37–39° C and to 41° C. Tumour tissues, embryo tissues and regenerating liver react to this in the same way. The degree of inhibition in all these tissues is proportionate to both the extent and the duration of the increase in temperature. Our findings also speak for an individual sensitivity to heat among the tumours tested and among other rapidly proliferating tissues. The simultaneous application of heat and Bleomycin leads to no additive effect either with Jensen's sarcoma or with tumour GW-39. On the other hand, hydroxyurea and heat applied simultaneously show an additive inhibitory effect on the incorporation of ³H-thymidine in tumour GW-39.As no corresponding influences of temperature are to be proved with non-proliferating tissues, the observed sensitivity to temperature appears to be a peculiarity of proliferating cell systems. The question must therefore be clarified as to whether this sensitivity is expressed only under the conditions of the in vitro experiment or whether it is to be regarded as evidence of a general sensitivity to heat in the nucleic acid biosynthesis of rapidly proliferating groups of cells.

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Mit Unterstützung der Deutschen Forschungsgesellschaft.     

New aromatic compounds from the marine mangrove Bruguiera gymnorrhiza

The phytochemical investigation of the stem of Bruguiera gymnorrhiza yielded five new aromatic compounds (1-5), of which the bruguierols A - C (1-3) represent a new structural skeleton in natural product chemistry. All structures have been determined by NMR spectroscopic studies. Among them, 3 showed moderate activity against Gram-positive and Gram-negative bacteria including mycobacteria and resistant strains (MICs 12.5 microg/mL).     

Weekly vinblastine in pediatric low-grade glioma patients with carboplatin allergic reaction

BACKGROUND: Carboplatin-based regimens have demonstrated activity in unresectable low-grade glioma (LGG) in children. Despite an interesting toxicity profile, the use of these regimens has been limited by the development of carboplatin hypersensitivity reaction (HSR) in up to 30% of patients. Desensitization has been the recommended approach for HSR. However, no guidelines have existed to aid physicians when carboplatin desensitization techniques fail. METHODS: A pilot study of monotherapy with weekly vinblastine for LGG in 9 children who developed carboplatin HSR on a carboplatin and vincristine regimen was performed. RESULTS: Vinblastine toxicity was moderate and readily manageable. None of the 9 patients had disease progression on therapy. Magnetic resonance imaging evaluation of tumor size from diagnosis to the end of vinblastine treatment showed 1 complete response (CR), 1 partial response (PR), 5 objective effects (OE), and 2 stable diseases (SD). CONCLUSIONS: This experience suggested that weekly vinblastine has a good efficacy to toxicity ratio in the treatment of LGG and can be a valuable option for children who develop severe HSR.