Tumoren der Sellaregion

Because of the complex anatomy, examination of the sella turcica and hypophysis needs a dedicated MR sequence protocol. Not every sellar lesion is a pituitary adenoma. Thus, this review article summarizes the most frequently encountered intra-, supra-, and parasellar tumors and lesions. Differential diagnoses comprise besides adenoma among others craniopharyngioma, meningioma, glioma, germinoma, hamartoma, aneurysm, trigeminal schwannoma, pituitary carcinoma, chordoma, metastasis, infection, and empty sella. Characteristic imaging findings are presented and correlated to micro- and macro-pathology.     

MR-Spektroskopie bei Hirntumoren

MRT allows the anatomical visualization of intracerebral space-occupying lesions, and when magnetic resonance spectroscopy (MRS) is used in routine clinical practice it can give more information and be helpful in the diagnosis of such lesions. In MRS with long echo times for nerve tissue there are five metabolites that are particularly significant: N-acetyl aspartate (NAA), creatine, choline, lactate, and lipids. NAA levels are lowered in the presence of intracerebral tumors. Creatine is lowered in situations of hypermetabolic metabolism and elevated in hypometabolic conditions, but remains constant in many pathologic states and can be used as a reliable reference value. With malignant tumors there are usually elevated choline concentrations, reflecting increased membrane synthesis and a higher cell turnover. The lactate level rises following a switch in metabolism from aerobic to anaerobic glycolysis, and this is frequently observed in the presence of malignant tumors. The occurrence of lipid peaks in a tumor spectrum suggests the presence of tissue necroses or metastases. There are typical constellations that are seen on MRS for individual tumors, which are discussed in detail in the present paper.     

Impaired neutrophil functions in patients with leukocytoclastic vasculitis

Background Leukocytoclastic vasculitis (LV) is characterized by segmental inflammation of small blood vessels, resulting in ischemic damage to the surrounding tissue. It is considered to be related to a type III hypersensitivity reaction, although the exact etiologic mechanism is not clear. Objective The purpose of this study was to evaluate neutrophil functions in patients with LV in order to understand their role in the pathogenesis of the disease. Methods Neutrophil functions were examined in 25 LV patients. The patients were divided into two groups: Group A consisted of 14 patients with drug-induced LV and Group B consisted of 11 patients where LV was induced by other factors. Results Both groups of patients showed significantly reduced chemotaxis and phagocytosis. Superoxide generation was significantly lower (P < 0.001) only in neutrophils from patients in Group A: 5.8 ± 0.5 nmoles O₂/10⁶ cells/min compared to 9.08 ± 0.8 nmoles O2/106 cells/min in the controls. Preincubation on normal neutrophils with the patients' sera caused an increase in their superoxide generation in accordance with the high IL-8 levels in these sera. Conclusions Neutrophil functions were significantly impaired in patients with LV. It is likely that factors present in LV plasma may chronically activate neutrophils, so that they become refracfory to further stimulation. Our study showed that neutrophil superoxide generation is low only in drug-induced LV; this test may assist in distinguishing such patients from those with LV induced by other causes.     

Identification of the 2A10 antigen of retinal pigment epithelium as a beta 1 subunit of integrin

In previous studies the 2A10 antigen of retinal pigment epithelium (RPE) was described. It is a cell-surface monoclonal antibody-defined antigen whose properties suggest a possible role in cell adhesive interactions. This report identified the 2A10 antigen as a beta 1 subunit of the cell-surface extracellular matrix receptor protein, integrin. Comparative biochemical, immunochemical, and histochemical analyses of the 2A10 antibody and other antibodies directed against the beta 1 subunit of integrin indicate similar tissue distributions, immunoblotting patterns, tryptic digestion profiles, and coimmunoprecipitation of the 2A10 antigen and the beta 1 subunit of integrin. The 2A10 antigen/beta 1 subunit differed in molecular weight in different tissues, with the RPE demonstrating a form intermediate between neural and endoderm-derived tissues. The application of this new antibody to functional studies of the role of integrin in RPE cell-substrate adhesion is described in the accompanying paper.     

Prophylaxis against Soman Inhalation Toxicity in Guinea Pigs by Pretreatment Alone with Human Serum Butyrylcholinesterase

Human butyrylcholinesterase (HuBChE) has previously been shownto protect mice, rats, and monkeys against multiple lethal toxicdoses of organophosphorus (OP) anticholinesterases that werechallenged by iv bolus injections. This study examines the conceptof using a cholinesterase scavenger as a prophylactic measureagainst inhalation toxicity, which is the more realistic simulationof exposure to volatile OPs. HuBChE-treated awake guinea pigswere exposed to controlled concentration of soman vapors rangingfrom 417 to 430 µg/liter, for 45 to 70 s. The correlationbetween the inhibition of circulating HuBChE and the dose ofsoman administered by sequential iv injections and by respiratoryexposure indicated that the fraction of the inhaled dose ofsoman that reached the blood was 0.29. HuBChE to soman molarratio of 0.11 was sufficient to prevent the manifestation oftoxic signs in guinea pigs following exposure to 2.17 theinhaled LD50 dose of soman (ILD50, 101 µg/kg). A slightincrease in HuBChE:soman ratio (0.15) produced sign-free animalsafter two sequential respiratory exposures with a cumulativedose of 4.5 ILD50. Protection was exceptionally high and farsuperior to the currently used traditional approach that consistedof pretreatment with pyridostigmine and postexposure combinedadministration of atropine, benactyzine, and an oxime reactivator.Quantitative analysis of the results suggests that in vivo sequestrationof soman, and presumably other OPs, by exogenously administeredHuBChE, is independent of the species used or the route of challengeentry. This assuring conclusion significantly expands the databaseof the bioscavenger strategy that now offers a dependable extrapolationfrom animals to human.     

Lipid metabolism in Norplant-2 users--a two-year follow-up study. Total cholesterol, triglycerides, lipoproteins and apolipoproteins.

Changes in lipid metabolism in 25 healthy female volunteers during a 24-month application of Norplant-2 were evaluated in an open clinical trial. Total serum cholesterol decreased significantly (p less than 0.05/p less than 0.05) by 10%/9% after 12 months and by 3%/7% (n.s./n.s.) after 24 months of Norplant-2 use (all subjects/subjects completing 24 cycles). Serum triglycerides decreased by 34%/28% (n.s./p less than 0.05) after 12 months and by 29%/25% (p less than 0.05/p less than 0.05) after 24 months of Norplant-2 use (all subjects/subjects completing 24 cycles). HDL-cholesterol decreased significantly by 18%/12% (p less than 0.01/p less than 0.05) after 12 months and by 12%/12% (p less than 0.05/p less than 0.05) after 24 months of Norplant-2 use (all subjects/subjects completing 24 cycles). No statistically significant difference between serum levels of LDL-cholesterol prior to and after 12 and 24 months of Norplant-2 use could be found. VLDL-cholesterol levels decreased significantly by 38%/38% (p less than 0.05) after 12 and by 25%/25% after 24 months of Norplant-2 application (p less than 0.01) (all subjects/subjects completing 24 cycles). Apolipoprotein Al decreased significantly by 23%/23% (p less than 0.001/p less than 0.01) after 12 and by 21%/22% after 24 months of Norplant-2 application (p less than 0.01/p less than 0.01) (all subjects/subjects completing 24 cycles). No statistically significant difference between apolipoprotein All levels prior to and after 12 and 24 months of Norplant-2 implantation could be found. Apolipoprotein B decreased significantly by 27%/17% (p less than 0.05/p less than 0.05) after 12 months of Norplant-2 application (all subjects/subjects completing 24 cycles). The decline after 24 months of Norplant-2 use was not significant. Changes in lipid metabolism caused by oral hormonal contraceptives differ in the various clinical trials; however, most investigators found that serum levels of total cholesterol and triglycerides increase under the application of OCs. Contrary to this, a decrease of total cholesterol and triglycerides under Norplant-2 use was noted. Furthermore, we found a significant decrease of lipoproteins and apolipoproteins--with the exception of LDL-cholesterol and apolipoprotein All, which did not show any significant modifications. Thus, Norplant-2 seems to be non-contributory to cardiovascular risk and might even provide protection against such risks.     

Histological classification of uveal melanoma]

Cytological classification of choroidal malignant melanomas recommended by WHO and based on the Callender classification (spindle A and B, mixed and epithelioid) is presented. Prognosis according to the histological types is discussed.     

Comparative static biomechanical studies of tripod surface structures of cementless endoprostheses]

AIM: While the importance of stability of endoprosthetic surface structures has been recognized for some time there is a lack of comparative surveys and assessment indices that would permit comparison and improvement of surfaces on cementless endoprostheses. METHOD: Using separately produced, systematically mounted specimen pieces of endoprosthetic surfaces with isolated non-linked elements of varying shapes and sizes, stability parameters and stability behaviour are described. Results of tripode-structures are compared to spherical surfaces. RESULT: These investigations show clearly that geometrical attributes, the orientation and the contact of surface elements to the endoprosthetic stem influence the stability considerably more than the size of these surface elements. CONCLUSION: Using tripode-elements with different orientation, size and density, a differentiated formation of cementless endoprosthetic surfaces is possible.     

Thematic workshop on fluorescence compensation settings in multicolor flow cytometry

In his program of thematic one-day workshops, the French Association of Cytometry had organized a workshop dedicated to the fluorescence compensation settings in multicolor flow cytometry. This special day was in honor of our past President Jean Luc D'Hautcourt who has been involved in the quality of the use of flow cytometry in its clinical and research purposes. Review on fluorescence phenomena, compensation rules, settings, and few observed confounding situations were presented.