Comparison of the blood-brain barrier and liver penetration of acridine antitumor drugs

Summary The blood-brain barrier penetration of amsacrine and its analogs 9-({2-methoxy-4-[(methylsulfonyl)-amino]phenyl}amino)-,5-dimethyl-4-acridine carboxamide (CI-921) and M-[2-(dimethylamino)ethyl]-acridine-4-carboxamide (AC) was measured in the barbiturate-anesthetized mouse. After intracarotid administration, AC was almost completery extracted (90%) in a single transit through the brain capillaries, whereas CI-921 (20%) and amsacrine (15%) were moderately extracted. AC is retained in the brain; no loss of AC from the brain was apparent at 1, 2, 4, or 8 min after injection. In contrast, after intraportal administration, 75% of the AC, 94% of the CI-921, and 57% of the amsacrine was extracted in a single transit through the hepatic vasculature. Rather than being retained in the mouse liver, these acridine antitumor agents show time-dependent loss (t _1/2=10 min for amsacrine and AC, 24 min for CI-921). We conclude that unlike most antitumor agents, these acridine drugs appear to penetrate the blood-brain barrier readily.This study was supported by the Auckland Medical Research Foundation (New Zealand), by the Medical Research Foundation (New Zealand), by the National Science Foundation (United States/New Zealand Cooperative Science Program), by the United States Veterans Administration, and by NIH grant NS 25554     

Gastric cancer mortality and nitrate levels in Wisconsin drinking water.

The association between nitrate levels in public and private sources of drinking water and gastric cancer mortality in Wisconsin was investigated in a case-control study. All gastric cancer deaths of Wisconsin residents from 1982 through 1985 were compared with deaths from other causes (controls), and nitrate levels in the home drinking water of these residents were determined. Nitrate measures for public sources were obtained from historic nitrate data from municipal sources that existed in 1970. Nitrate measures for private water sources were obtained by testing the wells individually at the existing residences. Controls were matched individually to gastric cancer cases with respect to sex, year of birth, year of death, Wisconsin birth, and Wisconsin residency at the time of death. Matched-pair analyses were performed on the paired data, and the following levels of nitrate-nitrogen exposure were used as indicators of exposure: 0.5, 2.5, 5.0, and 10.0 mg/l. Matched-pair analysis was also performed for which private water supply constituted exposure. Odds ratios and 95% confidence intervals were, respectively, 0.92 (0.75, 1.12); 0.97 (0.74, 1.35); 0.86 (0.69, 1.08); 1.50 (0.12, 18.25); and 1.09 (0.82, 1.47) for exposure to private well-water sources. These results did not indicate an increased risk of gastric cancer at any level.     

Suppression of presynaptic calcium currents by hypoxia in hippocampal tissue slices.

We tested the hypothesis that suppression of inward calcium current in presynaptic terminals is the cause of failure of synaptic transmission early during cerebral hypoxia. Postsynaptic responses in CA1 zone of hippocampal tissue slices were blocked either by the combined administration of 6,7-dinitroquinoxaline-2,3-dione (DNQX) and 3-((+-)-2-carboxypiperazine-4-yl)-propyl-1-phosphonic acid (CPP) or by lowering extracellular calcium concentration ([Ca2+]o). Repetitive orthodromic activation of central neurons caused transient decrease of [Ca2+]o (measured by ion selective microelectrodes) in neuropil, attributable to influx of Ca2+ in presynaptic terminals. Presynaptic [Ca2+]o responses were rapidly and reversibly suppressed when oxygen was withdrawn from hippocampal tissue slices. The 'resting' baseline level of [Ca2+]o declined at first gradually, then precipitously as in spreading depression (SD). Presynaptic volleys during high frequency train stimulation were also depressed somewhat before SD began. We conclude that (1) presynaptic Ca2+ currents fail during hypoxia, perhaps because 'resting' intracellular free Ca2+ activity is increased and, in part, also because of partial failure of presynaptic impulse conduction; (2) the influx of Ca2+ into brain cells in hypoxic spreading depression is not mediated by glutamate/aspartate dependent channels.     

Renal tubular epithelial cells express osteonectin in vivo and in vitro.

Osteonectin (SPARC, culture shock protein, BM-40) is a widely distributed glycoprotein which binds calcium and several extracellular matrix proteins, including interstitial collagens and thrombospondin, but whose physiologic role remains undefined. In the present studies, we have demonstrated that immunoreactive osteonectin is present in the distal cortical tubule and medullary tubules of murine kidney. We surveyed the renal epithelial cell lines LLC-PK1, MDCK, and OK for the expression of mRNA encoding osteonectin. We found that osteonectin mRNA is expressed by LLC-PK1 and OK cells but not by MDCK cells, as well as by adult kidney from several species. Calcitonin and vasopressin, agents which increase cAMP in these cells, were found to decrease steady-state osteonectin mRNA concentrations. We found that LLC-PK1 cells produced osteonectin protein, that the protein was localized to intracellular granules, and that the protein bound hydroxyapatite in vitro. Pulse-chase analysis revealed that osteonectin was secreted from the cell layer to the medium after a lag time of four to six hours and was secreted preferentially from the basolateral domain of the cell. The preferential secretion of the calcium-binding protein osteonectin from the renal epithelial cell is consistent with several possible functions, including a structural extracellular matrix protein, a participant in transepithelial ion transport, and an inhibitor of extracellular calcification.     

Laparoscopic nephrectomy in a porcine model.

Laparoscopic nephrectomy was performed in 15 male pigs, the procedure was successful in 14. Extraction of the intact kidney through a 5-cm lower abdomen incision was done in 7 animals; complete destruction and evacuation of the kidney was accomplished by a round-knife suction device through a 1-cm port in another 7 pigs. Grossly, the specimen consisted of sausage-like tubular renal tissue and a small amount of tissue debris. Pathology revealed that the glomerular and tubular structures were well preserved, no interstitial hematoma could be found. Four ports were usually used, one 1-cm umbilical camera port, one 0.5-cm port for ureter traction, and two 1-cm working ports along the midclavicular line. All the pigs recovered uneventfully. The average operation time was 3 h 20 min. The application of endo-GIA (United States Surgical Corporation) for renal hilum reduced the operative time to 2 h 20 min. Complications included renal vein tear during endoclip application and cutting in the first case, mild subcutaneous emphysema in 2 cases. This first pig received exploratory laparotomy for the repair and ligation of the renal vein. No more major complications occurred with increasing experience. From this porcine experiment, we conclude that the combination of laparoscopy, a tissue destroyer and an endobag for the entrapment of kidney seem to be a promising technique for clinical nephrectomy.     

地塞米松减轻曲马多术后镇痛时恶心呕吐的临床观察

目的 :探讨地塞米松减轻曲马多术后镇痛时恶心呕吐的临床效果。方法 :选择术后自愿硬膜外镇痛(PCEA)的病例 6 0例 ,随机分为试验组 (地塞米松 曲马多 0 .15 %布比卡因 )和对照组 (格拉司琼 曲马多 0 .15 %布比卡因 )。结果 :两组病人术后疼痛评分 (VAS法 ) ,镇静评分及恶心呕吐的发生率无明显差异 (P >0 .0 5 )。结论 :地塞米松可以减轻曲马多术后镇痛时恶心呕吐的发生 ,效果良好 ,不增加副作用 ,价格便宜     

原发性中枢神经系统淋巴瘤35例临床分析

目的 探讨原发性中枢神经系统淋巴瘤的临床特点、诊断及治疗方法。方法 回顾性分析35例原发性中枢神经系统淋巴瘤的临床资料、病理特征及术前诊断方法。结果 本组男19例，女16例，男女比例为1．2：1。年龄26～72岁，平均年龄52岁。所有患者人免疫缺陷病毒(HIV)检查均为阴性。临床症状主要表现为颅内压增高、肢体无力、瘫痪和神经精神症状。57％的患者病史短于4周，发病急，病情进展快。肿瘤多位于额部、颚顶部和基底节区，本组共35例52个肿瘤，其中16例为多发性肿瘤(45．7％)。结论 原发性中枢神经系统淋巴瘤是一组异质性肿瘤，侵袭性大。病史短，发病急，病情进展快，常发生于幕上大脑半球，易多发，术前诊断困难．预后差．