Assessment of high-energy phosphorus compounds in the rat kidney by in situ31P nuclear magnetic resonance spectroscopy: effect of ischemia and furosemide

Summary ³¹P nuclear magnetic resonance (NMR) spectroscopy of the in situ rat kidney was performed by a surface coil method, and the effects of ischemia and furosemide infusion were assessed.³¹P NMR spectra of the kidney subjected to 30 min of ischemia returned completely to the pre-ischemic level after 60 min of reperfusion. But the³¹P NMR spectra after 60 min of ischemia did not recover, even after 120 min of reperfusion. Levels of -ATP and inorganic phosphate (Pi) decreased and the chemical shift of Pi increased after intravenous infusion of furosemide. This increase in chemical shift might signal an alkalotic change in intracellular pH. Furosemide infusion prior to ischemia is thought to protect the kidney from injury induced by 60 min of warm ischemia. The chemical shift of Pi returned to the pre-ischemic level earlier than -ATP and Pi. In conclusion, according to the findings of³¹P NMR spectroscopy, furosemide infusion prior to ischemia may be effective in protecting the kidney against ischemic injury. But the change in Pi peak and the causes of the dissociation of Pi and -ATP should be examined further.     

The renal nerves in the newborn rat

Immunocytochemical methods were used to investigate the distribution of afferent [calcitonin gene-related peptide-(CGRP) immunoreactive and substance P-immunoreactive] nerves and efferent (neuropeptide Y-immunoreactive and dopamine -hydroxylase-immunoreactive) nerves in the kidneys of rats within the 1st day of life. The newborn rat kidney possesses an afferent and efferent innervation. Both afferent and efferent nerves reach the kidney in the same bundles. The afferent sensory fibers predominate overwhelmingly in the renal pelvis and ureter while the efferent fibers clearly predominate in the vasculature. The corticomedullary connective tissue contains both types of innervation with a more prominent afferent innervation (CGRP immunoreactive). Only afferent arterioles of perihilar nephrons were innervated by efferent sympathetic fibers. The distribution and extent of afferent and efferent innervation is consistent with the renal nerves playing a significant role in the transition from fetal to newborn life. The close proximity between afferent and efferent fibers suggests a possible interaction between the two systems.     

肢体负压对周围动脉闭塞性病变犬皮肤SP免疫反应阳性神经纤维影响

目的　观察肢体负压对周围动脉闭塞性病变犬皮肤中 SP免疫反应阳性神经纤维的影响 .方法　犬 17只 ,随机分治疗组 10只、非治疗组 5只和正常对照组 2只 ,治疗组和非治疗组均将动物制作左后肢缺血模型 ,治疗组在模型制作后 14d,开始行患肢负压治疗 10 d(15 min·次 - 1 ) ;非治疗组不做负压治疗 ;正常对照组不行缺血模型制作及负压治疗 . 3组均行左后肢趾皮肤免疫组化染色 ,检测 SP免疫反应阳性纤维 .结果　非治疗组皮肤中 SP免疫反应阳性神经纤维均较正常对照组明显增多 (P<0 .0 1) ,治疗组较非治疗组减少(P<0 .0 1) ,但仍较正常对照组增多 .结论　肢体负压疗法可促进皮肤感觉神经纤维中 SP的释放     

P~(53)蛋白在口腔扁平苔藓癌变诊断中的意义

目的 :探索口腔粘膜扁平苔藓 (OLP) P53蛋白的表达及其在癌变诊断中的应用价值。方法 :采用 S- P免疫组化方法 ,观察在 2 5例 OLP、2 0例鳞癌 (OSCC)中 P53蛋白的表达。结果 :1 P53蛋白的阳性表达在 OLP早期已出现 ,各组间 P53阳性表达率间有显著性差异。2在 OSCC中其阳性表达率高达 80 % ,随着细胞异常增生程度的增高而增高。结论 :1在 OSCC的形成过程中 ,抑癌基因 P53的失活可能参与调节作用 ;2 P53蛋白作为判断 OLP癌变的辅助性参考指标 ,具有一定的可行性     

Enhancement of the response to purinergic agonists in P2Y1 transfected 1321N1 cells by antagonists suramin and PPADS

1. We have previously shown that both suramin and pyridoxal-phosphate-6-azophenyl-2′, 4′ disulphonic acid (PPADS) act as antagonists at transfected P2Y₁ receptors. Here we show that under certain experimental conditions these two P2 antagonists can enhance the response to agonists acting at these receptors.
2. The expression of either P2Y₁ or P2Y₂ receptors in 1321N1 human astrocytoma cells results, on a change of medium, in an elevation of basal (no added agonist) accumulation of [³H]-inositol(poly)phosphates([³H]-InsP_x) compared to cells not expressing these receptors. This elevation is much greater in P2Y₁ transfectants than in P2Y₂ transfectants.
3. Both PPADS and suramin reduced this basal level of [³H]-InsP_x accumulation in the P2Y₁ expressing cells.
4. When a protocol was used which required changing the culture medium, antagonists were added at a concentration which reduced the basal accumulation by about 50%, there was a significant stimulation in response to increasing concentrations of 2-methylthioadenosine 5′-triphosphate (2MeSATP), in the absence of antagonists there was no significant effect of the agonist.
5. However, when 2MeSATP was added in the absence of a change of medium and with no antagonist present, there was a several fold increase in [³H]-InsP_x accumulation. These results show that a release of endogenous agonist activity (possibly ATP/ADP) from the P2Y₁ expressing cells can create conditions in which a response to an agonist such as 2MeSATP can only be seen in the presence of a competitive antagonist.

     

Differential roles of neurokinin 1 and neurokinin 2 receptors in the development and maintenance of heat hyperalgesia induced by acute inflammation

1. Following induction of acute inflammation by intraarticular injection of kaolin and carrageenan into the knee joint in rats, there was a significant decrease in the withdrawal latency to radiant heat applied to the paw (i.e. heat hyperalgesia), an increased joint circumference and increased joint temperature.
2. A neurokinin₁ (NK₁) receptor antagonist (CP-99,994, 10 mM) had no effect on the paw withdrawal latency when it was administered spinally through a microdialysis fibre before the induction of inflammation. Pretreatment with a NK₂ receptor antagonist (SR48968, 1 mM) administered spinally through the microdialysis fibre prevented the heat hyperalgesia from developing in the early stages of the inflammation.
3. Post-treatment through the microdialysis fibre with the NK₁ receptor antagonist (0.0110 mM) was effective in reversing the heat hyperalgesia. In contrast, post-treatment spinally with the NK₂ receptor antagonist (0.011 mM) had no effect on the heat hyperalgesia. The inactive stereoisomers of the NK₁ receptor antagonist, CP100,263, or the NK₂ receptor antagonist, SR48965, administered at the same doses, had no effect on the joint inflammation or the heat hyperalgesia.
4. Pretreatment systemically with the NK₁ receptor antagonist (30 mg kg⁻¹) had no effect on the heat hyperalgesia or pain-related behaviour ratings where 0 is none and 5 is non weight bearing and complete avoidance of limb contact. Pretreatment with a NK₂ receptor antagonist (10 mg kg⁻¹) systemically prevented the heat hyperalgesia and pain-related behaviour ratings from developing in the early stages of the inflammation. The inactive stereoisomers of NK₁ receptor antagonist, CP100,263, or the NK₂ receptor antagonist, SR48965, administered at the same doses, had no effect on the joint inflammation or the heat hyperalgesia.
5. Post-treatment systemically with either the NK₁ (0.130 mg kg⁻¹) or the NK₂ (0.110 mg kg⁻¹) receptor antagonist resulted in a dose-dependent reversal of the heat hyperalgesia. Pain-related behaviour ratings were reduced by post-treatment only with the NK₁ receptor antagonist. The inactive stereoisomers of the NK₁ receptor antagonist, CP100,263, or the NK₂ receptor antagonist, SR48965, administered at the same doses, had no effect on the behavioural responses.
6. Direct pretreatment of the knee joint with either the NK₁ (30 mg) or the NK₂ (10 mg) receptor antagonist prevented the heat hyperalgesia from developing without affecting joint swelling. The inactive stereoisomers of the NK₁ receptor antagonist, CP100,263, or the NK₂ receptor antagonist, SR48965, administered at the same doses, had no effect on the joint inflammation or the heat hyperalgesia.
7. There appears to be a differential role for the spinal tachykinin receptors in the development and maintenance of the heat hyperalgesia associated with acute joint inflammation. The NK₂ receptors appear to be activated early in the development of the heat hyperalgesia and NK₁ receptors are involved in the maintenance of the heat hyperalgesia.
8. Peripherally, both NK₁ and NK₂ receptors are involved in the development of heat hyperalgesia and pain-related behaviour ratings induced by acute inflammation.

     

The NK1 receptor and its participation in the synergistic enhancement of corneal epithelial migration by substance P and insulin-like growth factor-1

1. We have previously shown that substance P (SP) and insulin-like growth factor-1 (IGF-1) act synergistically to enhance the migration of rabbit corneal epithelial cells in an organ culture model. The present study was designed to identify the epithelial cell SP receptor that participates in this synergistic effect.
2. Rabbit corneal blocks were incubated for 24 h, then the length of the path of epithelial migration was measured. Reagents tried in the TC-199 culture medium, in the presence or absence of IGF-1, were: SP, agonists of tachykinin receptors NK₁, NK₂ or NK₃ and antagonists of tachykinin receptors NK₁ or NK₂.
3. The binding characteristics of SP receptors were examined in rabbit cultured corneal epithelial cells by binding assays with [¹²⁵I]-SP in the presence or absence of excess unlabelled SP or ligands of NK₁, NK₂ or NK₃ receptors.
4. As was demonstrated previously, SP and IGF-1 stimulated epithelial migration when they were added to the culture medium together, but individually they had no effect. NK₁ agonists had the same synergistic effect with IGF-1 as did SP, but the NK₂ and NK₃ agonists did not. Furthermore, the NK₁ antagonist abolished the synergistic effect of SP and IGF-1, but the NK₂ antagonist had no effect.
5. SP bound specifically to rabbit cultured corneal epithelial cells. The binding affinity was 0.44 nM and there were 2.43×10⁴ binding sites per cell. The NK₁ ligand competed, in a dose-dependent fashion, with the binding of SP to corneal epithelial cells, but neither the NK₂ nor NK₃ ligand affected binding.
6. We conclude that the SP receptor in rabbit corneal epithelial cells is NK₁ and that this receptor participates in the synergistic enhancement of corneal epithelial migration by SP and IGF-1. The precise mechanism(s) of this interaction requires more study. These findings imply that both neural and humoral factors are essential for the maintenance and healing of corneal epithelium.

     

Amyloid-P-component-like immunoreactivity in β/A4-immunoreactive deposits in Alzheimer-type dementia brains

An immunohistochemical study using the mirror-image technique was performed in order to establish whether amyloid P component is involved in the mechanism of deposition of amyloid fibrils in senile plaques (SPs) in Alzheimer-type dementia (ATD). Ninety percent of /A4 protein-immunoreactive SPs were also stained by the anti-amyloid P component immunchistochemistry, and this applied to all of the diffuse, primitive and classical types of /A4 deposits. These findings may suggest an involvement of amyloid P component in the formation of amyloid fibrils in senile plaques in ATD brains.     

P0.1 is a useful parameter in setting the level of pressure support ventilation

Objective The purpose of this study was to investigate whether changes in breathing pattern, neuromuscular drive (P0.1), and the work involved in breathing might help to set the individual appropriate level of pressure support ventilation (PSV) in patients with acute respiratory failure (ARF) requiring ventilatory assistance.Design: A prospective, interventional study.Setting An 8-bed multidisciplinary intensive care unit (ICU).Patients Ten patients with ARF due to adult respiratory distress syndrome (ARDS), sepsis or airway infection were included in the study. Chronic obstructive pulmonary disease (COPD) patients with acute exacerbation were excluded. None of these patients was in the weaning process.Interventions We found a level of pressure support able to generate a condition of near-relaxation in each patient, as evidenced by work of breathing (WOB) values close to 0 J/l. This level was called PS 100 and baseline physiological measurements, namely, breathing pattern, P 0.1 and WOB were obtained. Pressure support was then reduced to 85%, 70% and 50% of the initial value and the same set of measurements was obtained.Measurements and results Flow ( ) was measured by a flow sensor (Varflex) positioned between the Y-piece of the breathing circuit and the endotracheal tube. Tidal volume was obtained by numerical integration of the flow signal. Airway pressure (P_aw) was sampled through a catheter attached to the flow sensor. Esophageal pressure (P_es) was measured with a nasogastric tube incorporating an esophageal balloon. The esophageal balloon and flow and pressure sensors were connected to a portable monitor (CP 100 Bicore) that provided realtime display of flow, volume, P_aw and P_es tracings and loops of P_es/V, P_aw/V and /V relationships. The breathing pattern was analyzed from the flow signal. Patient work of breathing (WOB) was calculated by integration of the area of the P_es/V loop. Respiratory drive (P 0.1) was measured at the esophageal pressure change during the first 100 ms of a breath, by the quasiocclusion technique. When pressure support was reduced, we found that the respiration rate significantly increased from PS 100 to PS85, but varied negligibly with lower pressure support levels. Tidal volume behaved in a similar way, decreasing significantly from PS 100 to PS85, but hardly changing at PS 70 and PS 50. In contrast, WOB and P 0.1 increased progressively with decreasing pressure support levels. The changes in WOB were significant at each stage in the trial, whereas P 0.1 increased significantly from PS 100 at other stages. Linear regression analysis revealed a highly positive, significant correlation between WOB and P 0.1 at decreasing PSV levels (r=0.87), whereas the correlation between WOB and ventilatory frequency was less significant (r=0.53). No other correlation was found.Conclusions During pressure support ventilation, P 0.1 may be a more sensitive parameter than the assessment of breathing pattern in setting the optimal level of pressure support in individual patients. Although P 0.1 was measured with an esophageal balloon in the present study, non-invasive techniques can also be used.     

Glutamatergic regulation of striatal peptide gene expression in rats

Summary The mRNA levels encoding enkephalin and substance P were measured in the rat striatum following cortical ablation, blockade of N-methyl-D-aspartate (NMDA) receptors or inhibition of glutamate release by lamotrigine. Unilateral ablation of the cerebral cortex resulted in a decrease of substance P mRNA levels particularly in the rostral dorsolateral and dorsomedial striatum ipsilateral to the lesion. There was a similar trend for a reduction in levels of enkephalin mRNA. Continuous, intrastriatal infusion of the competitive NMDA receptor antagonist, 3-((±)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid, (CPP, 0.12 and 1.2g/day) decreased both enkephalin mRNA and substance P mRNA in dose-dependent manner evenly throughout the striatum adjacent to the infusion site. Following subchronic administration of the presumed glutamate release inhibitor, lamotrigine (5 and 20 mg/kg IP) there was no significant alterations in either enkephalin mRNA or substance P mRNA levels in the striatum. Both enkephalin mRNA and substance P mRNA expression in the rat striatum appear tonically stimulated through postsynaptic NMDA receptor mediated mechanisms. This contrasts with differential dopaminergic modulation of peptides in striatal output neurons.