新麻醉药静松灵生物转化的研究

静松灵[2-(2,4-二甲基苯胺基)-4,5-二氢噻唑,XT]是国内合成的麻醉物,经ip给药后,从大鼠尿中分离、纯化、鉴定了四个代谢产物。MB₁即XT原形;MB₃及MA₂互为异构体,分别为2位、4位甲基氧化为羧基的产物;MA₁则4位甲基氧化为羧基,二氢噻唑环中4¹位亚甲基氧化为羰基。初步实验表明:代谢产物MB₃,MA²,MA₁的药效与毒性均远低于原形药,大鼠与小鼠对XT的转化机制相近,但也存在种属的差异。     

Neonatal alloimmune thrombocytopenia due to a new platelet-specific alloantibody

An infant with severe neonatal alloimmune thrombocytopenia is described in whom an antibody directed at a new platelet-specific alloantigen, Ca (HPA-6b), is implicated. The new alloantigen is of low frequency in the population and was localized to platelet glycoprotein (GP) IIIa. Immunoprecipitation studies using murine monoclonal antibodies specific for the GP complex IIb-IIIa and GPIIIa alone (AP2 and AP3) suggest that the location of the Ca epitope on GPIIIa may be near the binding site for AP3. Neonatal alloimmune thrombocytopenia associated with Ca is likely to be as severe as that seen in cases due to incompatibilities for the HPA-1 (PIA) and HPA-4 (Pen) platelet alloantigen systems, because each is located on GPIIIa, a densely represented molecule on the platelet surface.     

Tumors of the central nervous system studied by computed tomography and ultrasound

Intraoperative ultrasound (US) was compared to computed tomography (CT) in 41 intracranial and 6 spinal cord tumors. The studies correlated closely except for primary gliomas. Eight of the 22 primary intracranial gliomas (37%), including 1 low-grade and 7 anaplastic tumors, were larger and more extensive on US than on CT. Margins of non-enhanced primary astrocytomas were shown by US but not CT. Four anaplastic tumors (19%) exhibited echogenicity extending beyond the enhanced area. In 4 patients an enhanced lesion contained a lucent center which proved to be echogenic. Low-grade astrocytomas were relatively homogeneous on US, while anaplastic astrocytomas were more inhomogeneous. Cysts could be found in both types of astrocytomas and were often small and multiple. The echo pattern was not helpful in differentiating metastases from primary tumors, although all of them had sharp margins. Sonography of the central nervous system can provide valuable information about tumor morphology and margins.     

Assessment of congenital heart defects by dynamic three-dimensional echocardiography: methods of data acquisition and clinical potential

To evaluate the use of three-dimensional (3D) echocardiography in the diagnosis of congenital heart defects, we studied 238 patients aged 3 days to 19 years (mean 4.3 years) with normal hearts ( n = 13) or a variety of congenital heart defects (n = 225) Three different modalities of data acquisition suitable for reconstruction were applied For parallel scanning, the transducer is held in a 6-cm long scan frame and then moved over the thorax, or in the subcostal position, by a stepper motor using 0.5-mm steps with acquisition of perpendicular parallel images of the heart For rotational scanning, the transducer is rotated at sectors of 2° over a span of 180° For fan-like scanning, the transducer is moved in an arc 45° each way from its vertical axis Movement of the transducer is computer-controlled and performed with electrocardiography and respiratory gating Between 80 and 120 slices of the heart are thus obtained, which form the dataset This dataset can then be "sectioned" in any desired plane, thus permitting generation of views simulating intraoperative perspectives Ventricular septal defects and atrioventricular valves can be displayed as viewed via the atrium Muscular ventricular septal defects can be viewed as seen through a ventriculotomy Obstruction in the left ventricular outflow tract can be viewed as via an aortotomy, and so on We conclude that this new imaging modality has a vast potential and may facilitate planning of intracranial surgery.     

Cerebral microgyria, thalamic cell size and auditory temporal processing in male and female rats

Induction of microgyria by freezing injury to the developing somatosensory cortex of neonatal rats causes a defect in fast auditory processing in males, but not in females. It was speculated that early damage to the cortex has sexually dimorphic cascading effects on other brain regions mediating auditory processing, which can lead to the observed behavioral deficits. In the current series of experiments, bilateral microgyri were induced by placement of a freezing probe on the skulls of newborn male and female rats, and these animals were tested in adulthood for auditory temporal processing. Control animals received sham surgery. The brains from these animals were embedded in celloidin, cut in the coronal plane and the following morphometric measures assessed: microgyric volume, medial geniculate nucleus (MGN) volume, cell number, and cell size, and, as a control, dorsal lateral geniculate nucleus (dLGN) volume, cell number and cell size. There were no sex differences in the cortical pathology of lesioned animals. However, microgyric males had more small and fewer large neurons in the MGN than their sham-operated counterparts, whereas there was no difference between lesioned and sham-operated females. There was no effect on dLGN cell size distribution in either sex. Microgyric males were significantly impaired in fast auditory temporal processing when compared to control males, whereas lesioned females exhibited no behavioral deficits. These results suggest that early injury to the cerebral cortex may have different effects on specific thalamic nuclei in males and females, with corresponding differences in behavioral effects.      

Induction of tumor-specific T cell response by cognating tumor cells with foreign antigen-primed Th cells

Sufficient CD4+ T cell help is very important in generating specific cytotoxic T cell responses. The inadequate activation of tumor-specific Th cells leads to failure of antitumor immunity. In general, each individual consists of some primed Th cells responding to certain antigens. If these tumor non-specific pre-primed Th cells can provide sufficient help, the generation of tumor-specific T cells may be enhanced. In the present study, we tested this hypothesis by cognating and reactivating pre-primed ovalbumin (OVA)-specific Th cells with OVA- pulsed tumor cells which could simultaneously present both OVA and tumor-associated antigen on the same cell. We clearly demonstrated that immunization of OVA-sensitized mice with OVA-pulsed P388 cells, but not unpulsed P388 cells, led to the induction of P388-specific cytotoxicity and tumor resistance. Both CD4+ and CD8+ tumor-specific cytotoxic T cells were detected in vitro, but only CD8+ T cells played the major effector role in preventing the growth of challenged tumor in vivo. Taken together, our study demonstrated that the immunogenicity of tumor cells can be enhanced effectively by cognating pre-primed foreign antigen-specific Th cells with tumor cells. These findings have potential implications in developing methods to control tumor growth.