二维超声和彩色多普勒对肝脏炎性假瘤的诊断价值15例分析

目的探讨二维超声和彩色多普勒对肝脏炎性假瘤（IPL）的诊断价值。方法回顾性分析15例16个经手术或超声引导下穿刺活检病理证实的IPL病灶的声像学资料。结果IPL的声像图表现大部分是实质性低回声不均质病灶，形态不规则，边界尚清，病灶直径均为〈50mm，内部多无血流信号（11／16），少数可见低速、低阻的动脉血流频谱（3／16）和静脉型血流频谱（2／16），肝脏本身均无硬化表现。结论二维超声和彩色多普勒可反映IPL的血供特点及一些病理特征，对定性诊断与鉴别诊断有较高的临床价值。     

GABAA receptor antagonism in the ventrocaudal periaqueductal gray increases anxiety in the anxiety-resistant postpartum rat

Postpartum mammals show suppressed anxiety, which is necessary for their ability to appropriately care for offspring. It is parsimonious to suggest that the neurobiological basis of this reduced anxiety is similar to that of non-parturient animals, involving GABA_A receptor activity in sites including the midbrain periaqueductal gray (PAG). In Experiment 1, postpartum and diestrous virgin female rats received an intraperitoneal injection of the GABA_A receptor antagonist (+)-bicuculline (0, 2 and 4 mg/kg) and anxiety-related behavior was assessed with an elevated plus maze. The 4 mg/kg dose of (+)-bicuculline significantly increased anxiety-related behavior, particularly in the postpartum females. Experiment 2 revealed that bicuculline's action was within the central nervous system, because anxiety in neither dams nor virgins was significantly affected by intraperitoneal injection of bicuculline methiodide (0, 2 and 6 mg/kg), which does not readily cross the blood-brain-barrier. In Experiment 3, bicuculline methiodide (2.5 ng/side) was directly infused into the ventrocaudal PAG (cPAGv) and significantly increased dams' anxiety compared to saline-infused controls. These studies expand our knowledge of how GABA_A receptor modulators affect anxiety behaviors in postpartum rats to the widely-used elevated plus maze, and indicate that the postpartum suppression of anxiety is in part a consequence of elevated GABAergic neurotransmission in the cPAGv.     

Differential Activation of the Periaqueductal Gray by Mild Anxiogenic Stress at Different Stages of the Estrous Cycle in Female Rats

The effect of acute exposure to mild anxiogenic stress on cutaneous nociceptive threshold was investigated in female Wistar rats at different stages of the estrous cycle. Baseline tail flick latencies did not change significantly during the cycle. However after brief exposure to vibration stress (4 Hz for 5 min), rats in late diestrus, but not at other cycle stages, developed a hyperalgesia (decrease in tail flick latency). Animals in late diestrus revealed a more than fivefold increase in the density of Fos-like immunoreactive nuclei in the dorsolateral, lateral, and ventrolateral columns in the caudal half of the periaqueductal gray matter (PAG). There was no change in the density of Fos-like immunoreactive nuclei in the PAG in rats in estrus and early diestrus, although rats in proestrus showed a smaller (50%) but significant increase. Rats undergoing withdrawal from a progesterone dosing regimen (5 mg/kg i.p. twice daily for 6 days) designed to mimic the fall in progesterone that occurs naturally during late diestrus, exhibited a stress-induced hyperalgesia that was similar to animals in late diestrus and a significant increase in Fos-positive cells in the PAG. We suggest that falling levels of progesterone during late diestrus may be a predisposing factor for the development of stress-induced hyperalgesia, which is linked to differential activation of descending pain control circuits in the PAG. Similar changes in women, when progesterone levels fall during the late luteal phase of the menstrual cycle, may contribute to the development of premenstrual symptoms that include increased anxiety and hyperalgesia.     

Central neural pathway mediating splanchnic osmosensation

To determine the central neural pathway which carries splanchnic osmosensory information to vasopressin (AVP) neurons in the hypothalamus, bilateral electrolytic lesions were placed in the ascending catecholaminergic fiber bundle, the locus coeruleus (LC), the locus subcoeruleus (subLC), the lateral parabrachial nucleus (LPB), the caudal periaqueductal gray (PAG) and the median preoptic nucleus (MPO). Six and seven days later, plasma AVP levels, plasma osmolality, mean arterial pressure and heart rate were measured following gastric infusion of hypertonic (598 mosm/kg; 2ml/4min) or isotonic (290 mosm/kg) saline in conscious rats with indwelling tail artery catheters and nasogastric tubes. The most effective pontine lesions, which were located in the ventral locus subcoeruleus (vsubLC) approximately 1.0 mm below the LC, decreased the AVP response to hypertonic gastric infusion by 59.7% (P < 0.05) as compared to sham-lesioned controls. In addition, unilateral vsubLC lesions dramatically reduced the catecholamine innervation of the ipsilateral paraventricular nucleus (PVN), as qualitatively determined with dopamine β-hydroxylase immunocytochemistry, suggesting that a pathway ascending with catecholaminergic fibers was disrupted. Lesions of the MPO were also very effective, decreasing the AVP response to hypertonic saline infusion by 60.3% (P < 0.05), suggesting that the MPO is an integral relay center in this pathway. On the other hand, LC, LPB and PAG lesions were ineffective. Systemic plasma osmolality or cardiovascular factors did not mediate the AVP response. These results demonstrate, for the first time, that splachnic osmotic information is transmitted to the hypothalamus via pathways within the ascending catecholaminergic fiber bundles, the MPO is a relay center where peripheral and central osmotic information may be integrated, and the LC, LPB and PAG are not part of the splanchnic osmotic pathway.     

Fine structure of adrenal medullary grafts in the pain modulatory regions of the rat periaqueductal gray

Summary Recent findings in our laboratory indicate that adrenal medullary grafts produce significant alterations in pain sensitivity. Electron microscopic studies were undertaken to correlate these behavioral changes with the neural interactions of the host and graft tissue in the periaqueductal gray. A striking change found 8 weeks after transplantation is that pronounced myelination has taken place both in the graft and in the host tissue. The new myelin formation in the graft has the typical appearance of PNS myelination and, in the host the appearance of CNS myelination. The endothelial cells of the capillaries in the grafted tissue are attenuated and fenestrated in contrast to those of the surrounding parenchymal tissue of the host. By 8 weeks, the graft becomes heavily encapsulated with collagen, while the host CNS tissue develops layers of glial processes outlining the graft. However, collagen and glial layers apparently do not form an absolute barrier to either cellular or humoral interaction between the host and graft tissue. Chromaffin cells can be found protruding into the host CNS tissue and sometimes forming synapses with presumably the host neuronal processes. Grafted chromaffin cells may participate as both postsynaptic and, less often, as presynaptic components of synaptic junctions. The behavioral relevance of these synaptic contacts is unclear, since similar implants of adrenal medullary tissue into the dorsal spinal cord subarachnoid space, which also induce potent analgesia, do not contain synapses. Thus, it is more likely that behavioral changes are brought about by diffusion of neuroactive substances from grafted chromaffin cells to host receptors.     

rCBF differences between panic disorder patients and control subjects during anticipatory anxiety and rest.

BACKGROUND: Our goal was to identify brain structures involved in anticipatory anxiety in panic disorder (PD) patients compared to control subjects. METHODS: Seventeen PD patients and 21 healthy control subjects were studied with H(2)(15)O positron emission tomography scan, before and after a pentagastrin challenge. RESULTS: During anticipatory anxiety we found hypoactivity in the precentral gyrus, the inferior frontal gyrus, the right amygdala, and the anterior insula in PD patients compared to control subjects. Hyperactivity in patients compared to control subjects was observed in the parahippocampal gyrus, the superior temporal lobe, the hypothalamus, the anterior cingulate gyrus, and the midbrain. After the challenge, the patients showed decreases compared to the control subjects in the precentral gyrus, the inferior frontal gyrus, and the anterior insula. Regions of increased activity in the patients compared to the control subjects were the parahippocampal gyrus, the superior temporal lobe, the anterior cingulate gyrus, and the midbrain. CONCLUSIONS: The pattern of regional cerebral blood flow activations and deactivations we observed both before and after the pentagastrin challenge was the same, although different in intensity. During anticipatory anxiety more voxels were (de)activated than during rest after the challenge.     

Periaqueductal gray inhibition of viscerointercostal and galvanic skin reflexes

In adult cats anesthetized with urethan-chloralose, effects of descending volleys from the mesencephalic periaqueductal gray (PAG) upon the viscerointercostal and galvanic skin reflexes were studied. The viscerointercostal reflex (VIR) was evoked by electrical stimulation of the greater splanchnic nerve and was recorded from the 11th, 12th or 13th intercostal nerve. Conditioning stimuli applied to the PAG inhibited the VIR. The inhibition was particularly marked when the nucleus raphe dorsalis (NRD) or its immediately adjacent ventromedial PAG was stimulated. A train of pulses was required in order to produce a recognizable PAG/NRD inhibition of the VIR. When the PAG/NRD was stimulated at 300-500 Hz, stimulation-produced inhibition became more pronounced in parallel with increase in number of pulses in each train and levelled off at about 5 pulses. The most effective frequency of PAG/NRD stimulation was found within this frequency range. Degree of PAG/NRD stimulation-produced inhibition of the VIR was dependent upon the strength of the test stimulus applied to the splanchnic nerve; the weaker the test stimulus, the more marked the inhibition. PAG/NRD stimulation-produced inhibition of the VIR was completely eliminated by bilateral section of the dorsolateral funiculi. The same section enhanced the VIR per se. It was suggested that PAG/NRD stimulation-produced inhibition of the VIR is mediated by descending pathways in the ipsi- as well as contralateral dorsolateral funiculi, and that the VIR per se is tonically inhibited by descending impulses in these pathways. PAG/NRD stimulation inhibited the segmental polysynaptic reflex in the intercostal nerve, but had little effect on the segmental monosynaptic reflex in the same nerve. Intravenous administration of morphine suppressed the VIR. The suppression was antagonized by intravenous naloxone. In contrast, PAG/NRD stimulation-produced inhibition of the VIR was unaffected by intravenous naloxone. Electrical stimulation of the splanchnic nerve evoked the galvanic skin reflex (GSR) from the forepaw pad. The GSR was inhibited by electrical stimulation of the PAG/NRD. The PAG/NRD stimulation-produced inhibition of the GSR was completely eliminated by intravenous administration of naloxone (0.4 mg/kg).     

Demonstration of a reciprocal connection between the periaqueductal gray matter and the reticular nucleus of the thalamus

Summary Lectin-conjugated horseradish peroxidase was either injected or implanted in crystalline form in various parts of the periaqueductal gray substance in the cat. After survival times ranging between 24 and 48 h the animals were fixed, and the mesencephalon and thalamus were sectioned and processed for peroxidase histochemistry, using tetramethylbenzidine as the chromogen. Light microscopic examination of the sections revealed that there exists a prominent reciprocal connection between the ventral and lateral parts of the periaqueductal gray matter on one hand, and the reticular nucleus of the thalamus on the other. The connections are mainly ipsilateral, and involve the entire rostrocaudal extent of the thalamic reticular nucleus, but mainly the ventrolateral sector of its caudal two thirds. There is a differential labelling within the thalamic reticular nucleus.     

南京市玄武区肺癌死亡率趋势分析和预测

目的　了解南京市居民肺癌死亡率的变化趋势。方法　整群抽样南京市玄武区居民 ,对 70年代以来居民病伤死亡资料进行分析 ,采用灰色模型预测近期肺癌死亡率。结果　南京市玄武区肺癌死亡率呈现不断上升的趋势 ,在全癌亡中的顺位由 70、80年代的第 2位跃居到 90年代以来的第 1位。目前在癌亡中所占比重为 2 3 4 5 %。男性肺癌死亡率及增长速度高于女性。灰色模型预测结果 ,至 2 0 0 0～ 2 0 0 2年 ,男女肺癌粗死亡率将分别达到 4 7 39/ 10万和2 2 6 3/ 10万 ;至 2 0 0 3～ 2 0 0 5年 ,分别达到 5 1 2 4 / 10万和 2 4 2 7/ 10万。结论　南京市肺癌死亡率已上升到恶性肿瘤死因之首。在今后的 5年中 ,肺癌仍将呈继续上升的趋势。