[Responses induced by dopamine in Xenopus laevis oocytes injected with mRNA from heat injured rat striatum]

Poly(A)(+) mRNA isolated from the striatum of normal rats and heat injured rats by RNAgents Total RNA Isolation System and PolyTract mRNA RNAgents Isolation Systems was microinjected into Xenopus laevis oocytes to express functional neurotransmitter receptors. Membrane currents were recorded by the conventional patch clamp technique for measuring the relative amounts of mRNA encoding dopamine receptor in order to study the change in dopamine receptors in heat injured rat striatum. There was no change in resting membrane potentials of the oocytes before and after mRNA injection. Dopamine induced membrane currents were shown to be mediated through Cl( ). The oocytes injected with mRNA from heat injured rat striatum were less sensitive to dopamine than those injected with mRNA from normal rats ( P<0.05). The above result showed that heat injury affected gene expression and signal transduction of dopamine receptors in rat striatum.

Design of cancer-specific antitumor agents based on aziridinylcyclopent[b]indoloquinones

The merits of N-unsubstituted indoles and cyclopent[b]indoles as DNA-directed reductive alkylating agents are described. These systems represent a departure from N-substituted and pyrrolo[1, 2-a]-fused systems such as the mitomycins and mitosenes. The cyclopent[b]indole-based aziridinylquinone system, when bearing an acetate leaving group with or without an N-acetyl group, was cytotoxic and displayed significant in vivo activity against syngeneic tumor implants. These analogues were superior to the others studied in terms of both high specificity for the activating enzyme DT-diaphorase and high percent DNA alkylation. Alkylation by a quinone methide intermediate as well as by the aziridinyl group could lead to cross-linking. The possible metabolites of the most active indole species were prepared and found to retain cytotoxicity, suggesting that in vivo activity could be sustained. The indole systems in the present study display selectivity for melanoma and, depending on the substituents present, selectivity for non-small-cell lung, colon, renal, and prostate cancers. The cancer specificities observed are believed to pertain to differential substrate specificities for DT-diaphorase.

[Selective arterial embolization for the treatment of thoracolumbar spinal tumor]

OBJECTIVE

To decrease intraoperative blood loss during tumor resection.

METHODS

Fifteen patients with primary thoraco-lumbar spinal tumor [giant cell tumor (5 patients), malignant nerinoma (2), chordoma (1), fibrous xanthosarcoma (1), malignant fibrohistocytoma (1), osteosarcoma (1), Ewing sarcoma (1), myeloma (1), leimyosarcoma (1), Non-Hodgkin diseases (1)] were treated by means of preoperative selective arterial embolization, tumor resection, and spinal reconstruction. Eight patients were subjected to total spondylectomy in one stage.

RESULTS

Fourteen patients showed satisfactory results after embolization. The volume of intraoperative blood loss ranged from 3,000 ml to 400 ml (average 1,200 ml). Follow up of the patients varied from 8 months to 19 years (average 48.7 months). Local recurrence happened in 3 patients; 3 patients died from metastasis. Three of 4 patients recovered from complete bowel movement and urination. Seven of nine patients had musical strength improved. Six of 8 patients had recovery of the e sensation of the lower limbs.

CONCLUSIONS

Selective arterial embolization before operation followed by operation within 24 hours can reduce intraoperative blood loss, shorten operative time, and provide a clear operative field for tumor resection.

Altered MAP kinase (ERK1,2) regulation in primary cultures of mammary tumor cells: elevated basal activity and sustained response to EGF

An elevation in total MAP kinase activity and expression has been observed in breast cancer tissue. However, the mechanisms underlying these changes in kinase activity and regulation by growth factors are not well characterized. In these studies, the effect of the potent mammary mitogen, epidermal growth factor (EGF), on the activation of the mitogen-activated protein kinases, ERK1 and ERK2 (extracellular regulated protein kinases 1 and 2, respectively), was compared in primary cultures of normal mouse mammary epithelial cells and in a hormone-responsive mouse mammary tumor. In normal epithelium, EGF stimulated an early rise in ERK activity at 4 min followed by a rapid decline, whereas a sustained (1 h) elevation of ERK activity was observed in the tumor cells. The time course of ERK activity in both cell types coincided with the phosphorylation state of the EGF receptor, suggesting that altered regulation of EGF receptor phosphorylation or EGF receptor turnover produces an enhanced ERK response to EGF in tumor cells. The MEK inhibitor, PD 098059 inhibited EGF-stimulated proliferation and ERK activity in a parallel, dose-dependent manner showing that ERK activation is at least permissive for the proliferative response to EGF. In addition, tumor cells showed a 4-fold elevation in basal (or ligand-independent) activity over normal cells without an increase in total enzyme level, and a preferential activation of ERK1 by EGF. These EGF-dependent and -independent changes in ERK regulation in the hormone-responsive mammary tumor underscore how multiple alterations in the regulation of this pathway may play a role in mammary tumorigenesis.

[Changes in [Ca2+]i and IP3 levels in the process of cisplatin-induced apoptosis of gastric carcinoma]

OBJECTIVE

To study the change and significance of intracellular-free calcium levels ([Ca2+]i) and inositol 1, 4, 5-trisphosphate (IP3) levels in the process of gastric carcinoma cell apoptosis induced by cisplatin.

METHODS

Apoptosis induced by cisplatin in gastric carcinoma BGC823 cell was investigated by light and electronmicroscopy, agarose gel electrophoresis and flow cytometry. [Ca2+]i was determined by Fura-2 fluorescin load technic, IP3 was determined by competitive protein binding method.

RESULTS

When BGC823 cells were treated with cisplatin (2 micrograms/ml) for 24 hours changes appeared typical of apoptosis. [Ca2+]i and IP3 were significantly increased, especially at the initial stage of apoptosis. However, from 2 to 24 hours after cisplatin treatment, IP3 levels progressively decreased, being significantly lower than those of the untreated controls.

CONCLUSION

In the process of cisplatin induced apoptosis of gastric carcinoma cells, [Ca2+]i and IP3 levels are up-regulated at the very initial stage but down-regulated from 2 hours afterwards.

[Dynamic change of intracellular-free calcium levels and its mechanism in the process of gastric carcinoma cellular apoptosis]

OBJECTIVE

To study the dynamic change of intracellular-free calcium levels ([Ca2+]i) and its mechanism in the process of gastric carcinoma cellular apoptosis.

METHODS

Apoptosis induced by cisplatin in gastric carcinoma cell was investigated by applying light microscopy, electron microscopy, agarose gel electrophoresis, and flow cytometry. [Ca2+]i was determined by applying Fura-2 fluorescein load technic, inositol 1,4,5-trisphosphate (IP3) levels were determined by applying competitive protein binding method.

RESULTS

Gastric carcinoma cell treated with cisplatin (2 micrograms/ml) for 24 hours expressed typical change of apoptosis, such as apoptosis body, cell shrinkage, condensation and fragmentation of chromosomes, DNA ladder bands, apoptosis beak in flow cytometry. [Ca2+]i in the process of gastric carcinoma cellular apoptosis was significantly higher than that in control groups, especially at the beginning stage of apoptosis. In the other experiment, we compared the common effect of cisplatin and verapanil (a kind blocking agent of calcium channel) on [Ca2+]i. Verapanil limited the increase of [Ca2+]i resulting from cisplatin. At the early stage of gastric carcinoma cellular apoptosis, IP3-levels were significantly higher.

CONCLUSION

Intracellular-free calcium is an important signal molecule in the process of signal transduction of gastric carcinoma cellar apoptosis, and [Ca2+]i is significantly higher, the increase of [Ca2+]i is resulted from the entry of extra cellular calcium and the release of intracellular calcium pools.

The interference effects of hexadecylphosphocholine on proliferation and membrane phospholipid metabolism in human myeloid leukemia cell lines

Membrane phospholipids are important regulators of cellular function. The phospholipid activities, such as lipid composition and transportation, contribute to cellular homeostasis in the lifespan of cells. Alterations in phospholipids result in the movement of bilayer lipids and the initiation of coagulation, recognition and internalization. Hexadecylphosphocholine (HePC) exerts antitumor potencies and represents a new class of antitumor agents targeted to the cellular membrane. Human myeloid leukemia cell lines HL-60 and K562 employed in this study were inhibited by HePC in vitro. The results indicate that the HL-60 cell line was sensitive, while K562 was resistant to HePC. Synthetic HePC is an alkyllysophospholipid analog which interacted with the cell membrane, thereby altering lipid composition and metabolism of membrane phospholipids and modulating intracellular calcium in human myeloid leukemia HL-60 and K562 cell lines. The contents of membrane phospholipids, including phosphatidylinositol (PI), phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidylethanolamine (PE), were determined quantitatively with high performance liquid chromatography. The sensitivity of myeloid leukemia HL-60 and K562 cell lines to HePC probably depends on the different distribution of these four phospholipids in the cellular membrane, or on the response of these phospholipids to HePC. The cytosolic free calcium ([Ca++]i) concentration increased by HePC confirmed that [Ca++]i was released from the intracellular calcium pool and is associated with cell differentiation and apoptosis. We investigated the hypothesis that the antiproliferative effect of HePC was mediated through the interference with cellular membrane phospholipids, including choline-containing phospholipids (PC), aminophospholipids (PE and PS) and PI, in eukaryotic cells.

Chemistry and DNA alkylation reactions of aziridinyl quinones: development of an efficient alkylating agent of the phosphate backbone

Described herein are detailed hydrolytic studies of a series of aziridinyl quinones, which trap nucleophiles when protonated. This study provided a compilation of the rate constants for nucleophile trapping and of the pKa values for the protonated aziridinyl quinones. A linear free energy relationship, including the antitumor agent DZQ, as well as other synthetic quinone derivatives, was obtained as a result of this study. Protonated DZQ has the relatively high pKa value of 3.8, which explains the enhanced cross-linking of DNA by DZQ and other related aziridinyl quinones at pH 4. The literature often shows aziridinyl quinone protonation occurring at the aziridinyl nitrogen, but the dependence of pKa values on quinone substituents indicates the presence of delocalization, which must arise from O-protonation. Also investigated were the DNA alkylation reactions of protonated aziridinyl quinones. At the outset of this study, we postulated that these "hard" electrophiles would alkylate the phosphate backbone of DNA. Bulk DNA is up to 35% alkylated by protonated aziridinyl quinones as judged by the incorporation of the quinone chromophore into the DNA. The presence of phosphate alkylation was verified by a 1H-31P NMR correlation experiment with DZQ-alkylated hexamer. Our modeling studies present a new picture of DZQ alkylation of DNA, where there is competition between N(7) and phosphate alkylation. The conclusions of this part of our study are that the phosphate backbone should be considered as a possible target of any DNA-alkylating agent and that an assessment of phosphate alkylation is best made with a 1H-31P NMR correlation experiment. Finally, the benzimidazole-based aziridinyl quinone 2 was observed to undergo aziridine ring opening followed by hydrolytic removal of the aminoethyl group from the quinone ring. This reaction was used to tag the phosphate backbone of DNA with aminoethyl groups. Such tags render anionic phosphates cationic and could also be employed as points of attachment for chromophores, spin labels, or other moieties to DNA.

[Effect of experimental immunological otitis media on inner ear]

We observed the change of the Outer Hair Cell (OHC) of the Guinea Pig (GP) in experimental immunological otitis media under a transmission electron microscope. Animals were immunized systemically with Bovine Serum Album (BSA) until high circulation serum levels developed, then were given BSA 1 mg/0.1 ml transtympanic challenge into one middle ear (ME) cleft on four successive weeks, after the 7th day of the ME challenge GP were killed. Under the transmission electron microscope, we observed that of the degeneration of mitochondrion and thinning of the sub membranous cistern, the damage in the 3rd row of OHC is more severe than the 2nd and the 1st rows. It suggested that immune reaction of ME may have an effect on the inner ear.

[Preliminary study on separation of three vitamins by capillary zone electrophoresis and micellar electrokinetic chromatography with amperometric electrochemical detection]

In this paper, separation of water soluble vitamins C (VC), B1 (VB1) and B6 (VB6) has been studied preliminarily by capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) with a home-made amperometric electrochemical detector at the working electrode [carbon fiber (5 microm o.d.)] potential of 510-540 mV (vs. SCE). It has been shown that each of the three vitamins has more than one peak in NH3-NH4Cl (pH 9.0) which were mainly caused by the decomposition products in weak base medium and by heat except those from impurities. The electrochemical detector has better performance for the three vitamins from CZE and MECC. They can be separated either by CZE or by MECC. The separation by CZE is better than that by MECC with sodium dodecyl sulfate (SDS). SDS and buffer acidity can influence the retention time, peak sequence and height. The separation efficiency of CZE in 0.01 mol/L NH3-NH4Cl was 468 800 theoretical plates for VC.

[Determination of changes in membrane phospholipids of rat lung and liver tissues from acute heat stress by high performance liquid chromatography]

The changes in the contents of phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) in lung and liver membrane tissues of rats suffered from acute heat stress were investigated with HPLC. The separation was performed on a mu-Porasil Si column, 300 mm x 3.9 mm i.d., by isocratic elution of acetonitrile : methanol : 85% phosphoric acid (100 : 3 : 1). The phospholipids were detected at 205 nm. The results showed that the contents (mean +/- SD) of PI, PS, PE and PC in normal rats liver were 270.0 +/- 18.2 microg/g, 133.7 +/- 8.6 microg/g, 1465 +/- 132 microg/g and 53.7 +/- 2.8 mg/g respectively, whereas those in heat-stressed rats whose rectal temperature was increased to 42 degrees C and maintained for 15 minutes were decreased by 14%-25% (P<0.01) except PS. When the heat-stressed rats recovered to room temperature for 4h, the contents of phospholipids returned to normal level. The changes of PS and PC in rat lung tissues were identical with those in liver tissues.

[Preventive effect of quinacrine on the development of heat injury by stabilizing membrane phospholipids metabolism and beta-adrenoceptor]

Previous studies have demonstrated that the activation of phospholipase A2 (PLA2) during heat stress would caused disorder of membrane phospholipids metabolism, accompanied by a decrease in phosphatidylcholine and phosphatidyl-serine and an increase in arachidonic acid. In heat stressed rats, a down-regulation of beta-adrenergic receptor in lung tissue was observed due to activation of PLA2. In the present work, it was demonstrated that pretreatment of rats with PLA2 inhibitor, quinacrine (20 mg/kg, I.P.), 1 h before heat stress could block these membrane lipid alterations, and the tolerance of rats to heat exposure was enhanced. The effect of quinacrine on the thermotolerance of marching soldiers with 15 kg of load under hot environment was also investigated. The results indicated that in the soldiers taken orally 200 mg quinacrine 1 h before marching, their heart rate, body temperature, accumulation of blood lactic acid and the changes of index of heart function were significantly improved as compared to the control group at the end of 3 h marching. According to these data, it can be concluded that quinacrine is a useful drug to prevent derangement of beta-adrenoceptor and membrane phospholipids metabolism in the development of heat stress. So as to prevent heat injury, and to improve tolerance to heat stress.

[Immunological observation on chyluric patients with heat-clearing and hemostatic drugs]

In order to investigate the pathogenesis and therapeutic mechanism of chyluria, an experiment with a basic Heat-clearing and hemostatic prescription was conducted in treating 30 patients of chyluria. The result, 26 cases were cured completely. The cell-mediated and humoral immunity observation showed that OKT3 and OKT4 levels were commonly low in chyluric cases, and OKT8 as higher than normal value, the OKT4/OKT8 ratio was inverted before treatment. While OKT3 and OKT4 increased commonly, and OKT8 decreased with the OKT4/OKT8 ratio adjusted after treatment. Meanwhile, humoral immunity level was also commonly low before treatment, it increased after treatment.

[Relationship between the changes in beta-adrenoceptor content and the metabolism of phospholipids in lung tissue from acute heat stressed rats]

To explore the relationship between the change of beta-adrenoceptor and the metabolism of phospholipids in lung tissue from acute heat stressed rats, the Bmax of beta-adrenoceptors, the activity of phospholipase A2 (PLA2), the content of phosphatidylcholine (PC) and phosphatidylserine (PS), and membrane fluidity in lung tissue of normal and heat stressed rats were investigated. The relevant parameter values mentioned above were 479 +/- 94 fmol/mg protein, 78.5 +/- 8.2 U, 53.5 +/- 1.7 mg/g.wet. w. and 425.1 +/- 68.1 micrograms/g.wet. w. respectively. Whereas in the heat stressed rats with rectal temperature raised to 42 degrees C for 15 min, the Bmax of beta-adrenoceptor was decreased by 43% (P less than 0.01), the activity of PLA2 increased by 83% (P less than 0.01), the contents of PC and PS decreased by 50% and 47% (P less than 0.01) respectively. A lower membrane fluidity in lung tissue for heat stressed rats was also demonstrated. The results suggest that the decreased binding sites of beta-adrenoceptor in lung tissue of rat during hyperthermia may be contributed to the activation of PLA2, which then accelerated the catabolism of phospholipids such as PC and PS in the cell plasma membrane, with a consequent alteration of membrane fluidity.