兔局灶脑缺血后脑片[Ca~(2 )]i的变化

目的：研究脑缺血后脑片[Ca2＋]i变化。方法：采用新型Ca2＋荧光指示剂Fura－2双波长法测定兔大脑中动脉阻塞（MCAo）局灶脑缺血后脑片细胞内游离钙（[Ca2＋]i）。结果：脑缺血后脑组织[Ca2＋]i显著升高。结论：[Ca2＋]i在脑缺血损害中起重要作用。     

Overexpression of the 18A2/mts1 gene and down–regulation of the TIMP–2 gene in invasive human glioma cell lines in vitro

Invasion of the reconstituted extracellular matrix composite, Matrigel, by eight human glioma–derived cell lines and human fetal brain cells was assessed in vitro using 8 um polycarbonate filters in a modified Boyden migration chamber. With the exception of one low grade glioma derived cell line, all lines studied proved to be invasive while normal fetal brain cells failed to invade. This invasive potential was independent of the histological grade of the tumour from which the cell lines originated. In addition, the expression of the metastasis–associated gene 18A2lmts1 as well as the tissue inhibitor of metalloproteinases–2 (TIMP–2) was analysed in each of the glioma–derived cell lines. The 18A2/mtsl was expressed in all the cells studied with the exception of fetal brain cells and the low grade non–invasive glioma derived IPRK–7 cell line. The 18A2/mtsl related genes coding for the S100 subfamily of calcium binding proteins were found to be differentially and overexpressed in invasive cell lines. TIMP–2 was expressed only in noninvasive cell lines. These results suggest that the 18A2/ mtsl and TIMP–2 genes could play an important role in the invasive behaviour of human glioma cells in vitro. .     

Lindane inhibition of [35S]TBPS binding to the GABAA receptor in rat brain.

The inhibition of [³⁵S]t-butylbicyclophosphorothionate ([³⁵S]TBPS) binding to the GABA_A receptor by the insecticide γ-hexachlorocyclohexane, lindane, was studied in several brain regions and using different membrane preparation methods, both in vitro and after dosing the animals with the chemical. In the latter studies, the amount of lindane remaining in the membrane suspensions used for binding assays was determined. In vitro data showed values of IC₅₀ from 150 to 1675 nM, varying in function of the membrane preparation method used. This may account for the discrepancies in IC₅₀ values found in the literature. IC₅₀ values within the range of 150–250 nM were determined using extensively washed membranes from several brain regions, so no evidence arose for brain regional differences in the affinity of lindane for the TBPS binding site. After different schedules of acute treatment with lindane, we found a manifest relationship between the extent of the observable inhibition of [³⁵S]TBPS binding and the lindane amount remaining in the membrane suspensions used for binding assays. This relationship was in good agreement with the in vitro data, so no support for an in vivo acute regulation of the binding site was obtained.     

Positron emission tomography in oncology

Summary. The particular advantages of positron emission tomography (PET) technique are that it has higher sensitivity, higher resolution, and a higher quality of image than that found in conventional nuclear medicine. The possibility of quantification and the wide range of useful tracers have raised expectations of this new method. To date, most of the human PET cancer studies have been performed with [¹⁸F]fluorodeoxyglucose (FDG) or [¹¹CJmethionine. These are good imaging agents for tumours. However, more specific radiopharmaceuticals are required if other features of tumour metabolism are to be observed, f¹¹Thymidine may prove to be a good tracer for quantitative measurements of tumour proliferation and [¹⁸F]misonidazole has been suggested for imaging of hypoxia.     

Molecular identification of a small supernumerary marker chromosome by in situ hybridization: diagnosis of an isochromosome 18p with probe L1.84

A dysmorphic child was found by cytogenetic analysis to have an extra small marker chromosome. The marker chromosome was shown to possess a chromosome 18 centromere by in situ hybridization, and probably represents an isochromosome 18p. Centromere specific probes should be of value in identifying extra small marker chromosomes, and thereby provide better understanding of the clinical significance of these.     

Metabolic myocardial viability assessment with iodine 123-16-iodo-3-methylhexadecanoic acid in recent myocardial infarction: Comparison with thallium-201 and fluorine-18 fluorodeoxyglucose

The best test presently available to ascertain residual viability within an infarct-related area involves the use of fluorine-18 fluorodeoxyglucose (FDG) to detect the persistence of some cellular metabolism. Rest reinjection of thallium-201 is a less accurate alternative but is easy to perform. Iodinated fatty acids, which are used with standard gamma cameras, are proposed as markers of cellular metabolism. This study was performed to assess the value of 16-iodo-3-methyl-hexadecanoic acid (MIHA) as a marker of the residual cellular metabolism by comparison with FDG in patients with a recent myocardial infarction, and to evaluate its contribution compared with the²⁰¹Tl stress-redistribution-reinjection technique. Stress-redistribution-reinjection²⁰¹T1 imaging, rest MIHA imaging and glucoseloaded FDG imaging were performed in 22 patients with recent myocardial infarction. Out of the 628 myocardial segments obtained from the left ventricular analysis, 400 were hypoperfused (relative uptake <0.75 of maximum uptake on stress²⁰¹T1 imaging), 177 of which were severely hypoperfused (relative uptake <0.50). Receiver operating characteristic (ROC) curves for predicting metabolic myocardial viability with FDG were derived from the results in respect of (a)²⁰¹T1 activity during exercise, redistribution and reinjection and (b) MIHA up-take, using the two FDG thresholds most commonly considered to define metabolic viability (0.50 and 0.60). Analysis of the 400 hypoperfused segments demonstrated that²⁰¹T1 reinjection was the most accurate test in predicting the presence of myocardial viability (area under the ROI curves=0.85 and 0.86 at the 0.50 and 0.60 FDG thresholds, respectively;P<0.05 vs other tests). The global predictive values of MIHA and²⁰¹T1 reinjection were, respectively, 0.87 and 0.89 at the 0.50 FDG threshold (NS), and 0.82 and 0.87 at the 0.60 FDG threshold (NS). When only the 177 severely hypoperfused segments were considered,²⁰¹T1 reinjection remained the most accurate test (accuracy 0.84 at the 0.50 FDG threshold and 0.82 at the 0.60 FDG threshold), while the accuracy of MIHA decreased significantly (0.78 at the 0.50 FDG threshold and 0.73 at the 0.60 FDG threshold,P<0.05 vs²⁰¹T1 reinjection). In all circumstances, MIHA was less specific than²⁰¹T1 reinjection for the detection of metabolic viability. In conclusion, in patients with recent myocardial infarction, MIHA accurately detects the persistence of metabolic viability, but is not superior to²⁰¹T1.     

Myocardial metabolic imaging by means of fluorine-18 deoxyglucose/technetium-99m sestamibi dual-isotope single-photon emission tomography

The detection of preserved glucose uptake in hypoperfused dysfunctional myocardium by fluorine-18 deoxyglucose (FDG) positron emission tomography (PET) represents the method of choice in myocardial viability diagnostics. As the technique is not available for the majority of patients due to cost and the limited capacity of the PET centres, it was the aim of the present work to develop and test FDG single-photon emission tomography (SPET) with the means of conventional nuclear medicine. The perfusion marker sestamibi (MIBI) was used together with the metabolic tracer FDG in dual-isotope acquisition. A conventional SPET camera was equipped with a 511-keV collimator and designed to operate with simultaneous four-channel acquisition. In this way, the scatter of 18F into the technetium-99m energy window could be taken into account by a novel method of scatter correction. Thirty patients with regional wall motion abnormalities at rest were investigated. The results of visual wall motion analysis by contrast cine-ventriculography in nine segments/heart were compared with the results of quantitative scintigraphy. The scintigraphic patterns of MIBI and FDG tracer accumulation were defined as normal, matched defects and perfusion-metabolism mismatches. Spatial resolution of the system was satisfactory, with a full width at half maximum (FWHM) of 15.2 mm for ¹⁸F and 14.0 mm for ^99mTe, as measured by planar imaging in air at 5 cm distance from the collimator. Image quality allowed interpretation in all 30 patients. 88% of segments without relevant wall motion abnormalities presented normal scintigraphic results. Seventy-five akinetic segments showed mismatches in 27%, matched defects in 44% and normal perfusion in 29%. We conclude that FDG-MIBI dual-isotope SPET is technically feasible with the means of conventional nuclear medicine. Thus, the method is potentially available for widespread application in patient care and may represent an alternative to the ²⁰¹T1 reinjection technique.     

人类乳头瘤病毒16,18型,p53基因与胃癌

３０例新鲜胃癌标本，采用多聚酶链反应技术检测人类乳头瘤病毒１６、１８感染、并采用多聚酶链反应－单链构象多态性技术对ｐ５３基因突变进行检测。结果：ＨＰＶ１５阳性率为４０．０％，未发现ＨＰＶ１８感染：Ｐ５３基因突变率为５０．０％，ＨＰＶ１６感染和Ｐ５３基因突变同时存在者为１６．７％。     

[H](+)S 14297: A novel, selective radioligand at cloned human dopamine D3 receptors

The selective dopamine D₃ receptor antagonist [³H](+)S 14297 ((+)-[7-(N,N-dipropylamino)-5,6,7,8-tetrahydro-naphtho(2,3b)dihydro,2,3-furane]), labelled to high specific activity (145 Ci/mmol), bound to cloned human dopamine D₃ receptors but displayed negligible binding to cloned human D₂ receptors. [³H](+)S 14297 exhibited rapid association and dissociation, high affinity saturable binding (K_d = 7.0 nM) and a competition binding profile highly correlated with that of [¹²⁵I]iodosulpride (r = 0.98).