Immunological abnormality in C3H/HeJ mice with heritable inflammatory bowel disease

To explore the immunological abnormality of a heritable inflammatory bowel disease developed in a new substrain of C3H/HeJ mice, we examined the expression of integrins beta7 and other cell adhesion molecules on normal and disease mice lymphocytes by flow cytometry. We also examined the cytotoxicity of small intestinal intraepithelial lymphocytes to epithelial cells and the proliferation and aggregation of intestinal lymphocytes. There are several significant changes in the expression levels of alpha4 and alphaM290beta7 integrins, CD11a, ICAM-1, CD45RB, CD4, CD44, and CD45 in different lymphocyte populations. The cytotoxicity of small intestinal intraepithelial lymphocytes from disease mice was higher than that from normal mice and could be stimulated by PHA and inhibited by mAb to alphaM290beta7. The proliferation of both normal and disease small intestinal intraepithelial lymphocytes was enhanced by costimulation by mAb to CD2 or CD3 and ProNectin. In comparison to disease mice, normal small intestinal intraepithelial lymphocytes proliferated at a significantly higher rate in response to sheep RBC and mAb to CD2 or CD3 and ProNectin costimulation. Homotypic aggregation of small intestinal intraepithelial lymphocytes isolated from disease mice was greater than in those from normal mice. The abnormality of expression of integrin beta7 and other cell adhesion molecules and cytotoxic, proliferative, and aggregative responses of lymphocytes from disease mice may play important roles in the pathogenesis of this heritable inflammatory bowel disease.

A new simple method for isolation of microvascular endothelial cells avoiding both chemical and mechanical injuries

Our study indicates that when small pieces of lung or muscles of chest wall are cultured, erythrocytes and leukocytes (PMNs) leave the tissues first, followed by vascular endothelial cells (ECs). Fibroblasts and other mixed cells grow after 72 hr culture. The ECs can then be isolated avoiding mechanical and chemical injuries. The lung tissue is obtained from the peripheral surface and muscles from the chest. It is then cut into pieces and cultured with DMEM containing 20% fetal bovine serum. After 60 hr culture, the tissues are discarded. The flask contains only ECs and blood cells. Blood cells can be cleared out after the cells are subcultured once or twice. The primary cells and the subcultured cells cultured on gelatinized culture dish give the capillary-like structure. Cells cultured on untreated dishes have regular cobblestone morphology and junctional contacts. The isolated cells were not mesothelial cells because the cells did not react to antibody against cytokeratin 18, while mesothelial cells reacted strongly to the antibody. The cells can be isolated from the lung tissue without pleura. The primary microvascular ECs are also cultured on microcarriers (cytodex 3). Because both mechanical and proteolytic injuries are avoided, the cells may be more similar to cells in the in vivo state. There are no significant differences in PMN-endothelium adherence and monolayer responses to second messengers, platelet activating factor, and phospholipase A2 when pulmonary and muscular microvascular endothelial cells are compared.

1 alpha,25-Dihydroxyvitamin D3 decreases scalding- and platelet-activating factor-induced high vascular permeability and tissue oedema

We have previously demonstrated that 1,25-dihydroxyvitamin D3 decreases endotoxin-induced mortalities of rat and mouse from 80% and 70% to 14% and 10% (unpublished results). In the present study, pretreatment of 1,25-dihydroxyvitamin D3 decreased pad oedema and pulmonary vascular permeability induced by scalding and platelet-activating factor. 1,25-Dihydroxyvitamin D3 in a dose of 4 x 10(-9) mol/kg decreased pulmonary extravascular Evans blue concentration increased by platelet-activating factor from 6.32 +/- 0.63 ng/g to 2.57 +/- 0.28 ng/g (P < 0.01), and lung water/dry lung weight from 3.79 +/- 0.57 to 1.51 +/- 0.13 (P < 0.01). 1,25-Dihydroxyvitamin D3 of 4 x 10(-11) moles/kg and calcipotriol (a vitamin D analogue which has limited hypercalcaemic effect) of 4 x 10(-9) moles/kg had similar effects. Karyocyte counting of bronchoalveolar lavage fluid and the reduction of mean arterial pressure were also reduced to some extent. These results suggest that 1,25-dihydroxyvitamin D3 may be a new and effective drug to reduce vascular permeability and ameliorate oedema.

Expression of the conditioned NK cell activity is beta-endorphin dependent

We are interested in identifying the pathways which are responsible for triggering the conditioned enhancement of natural killer (NK) cell activity. Earlier studies have suggested that central opioid(s) are involved in eliciting the expression of the conditioned NK cell activity. The purpose of this study was to identify the central opioid peptides that allow the central nervous system (CNS) to communicate with the immune system. Mediators that activate the efferent pathway of communication between the CNS and immune system was examined by injection of the mediator via the cisterna magna (CM). Conditioning was used as a tool to show that the bi-directional communication between the CNS and the immune system does take place. We found that beta-endorphin but not dynorphin could stimulate NK cell activity, when beta-endorphin or dynorphin was injected into the CM. In addition, when anti-beta-endorphin or anti-dynorphin antibody was injected into the conditioned animals via CM the conditioned response was blocked by anti-beta-endorphin but not by anti-dynorphin antibody. These observations suggest that beta-endorphin appears to be one of the signals that is induced in the brain at the CS recall step of the conditioned response to trigger the elevation of NK cell activity.

A multicentred phase III comparative clinical trial of Mesigyna, Cyclofem and Injectable No. 1 given monthly by intramuscular injection to Chinese women. I. Contraceptive efficacy and sid effects

A phase III clinical study was carried out among 5680 fertile Chinese women to evaluate efficacy and side effects of three monthly injectable contraceptives: Mesigyna, Cyclofem and Chinese Injectable No. 1. When used in a once-a-month treatment schedule (part 1 of study), the effectiveness of Chinese Injectable No. 1 was unacceptably low; 36 pregnancies occurred during the first 1743 women-months of use, 16 before the second injection. The study was restarted with a revised injection schedule for Injectable No. 1: two injections separated by 9 +/- 1 days during the first month and subsequent injections given 10-12 days after the onset of bleeding, or if no bleeding occurred, 28 days after previous injection. In part 2 of the study, 988, 990 and 992 subjects were provided Mesigyna, Cyclofem and Injectable No. 1, respectively. Life-table pregnancy rates at one year were 0.41%, 0% and 0.77% (p < 0.05), respectively; the overall discontinuation rates at one year were 13.9%, 19.1% and 20.4% (p < 0.001). Discontinuation rates for bleeding problems were significantly different between the groups: discontinuation rates for amenorrhea were 0.58%, 3.71% and 0.68% (p < 0.001) for Mesigyna, Cyclofem and Injectable No. 1; for other bleeding problems, the rates were 4.88%, 8.38% and 12.64% (p < 0.001). There were no significant differences between the groups regarding discontinuation for other medical or non-medical reasons. Mean weight changes after one year of use were small: 0.73, 0.86 and 0.17 kg for the three groups, respectively. Both Mesigyna and Cyclofem were very effective for contraception, but Mesigyna appeared to be tolerated slightly better with regard to cycle control; the modified dose regimen for Injectable No. 1 also gave a low pregnancy rate but was associated with higher rates of discontinuation.

A multicentred phase III comparative clinical trial of Mesigyna, Cyclofem and Injectable No. 1 given by intramuscular injection to Chinese women. II. The comparison of bleeding patterns

Between 1988 and 1992, a randomized phase III clinical trial was conducted in China to compare three monthly injectable contraceptives: Mesigyna, Cyclofem and Injectable No. 1. This paper presents a detailed analysis of the menstrual diaries provided by 5098 (89%) of the subjects. In total, 902, 903 and 913 diaries were analyzed to compare bleeding patterns induced by Mesigyna, Cyclofem and Injectable No. 1. The first withdrawal bleeding usually occurs 14-20 days after the first injection for all three of these preparations. Thereafter, 50% of Mesigyna users had precisely 3 bleeding/spotting episodes every 90 days, 50% of Cyclofem users had 2-3 and 50% of Injectable No. 1 users had 3-4 episodes every 90 days. Relative to users of Mesigyna or Cyclofem, Injectable No. 1 users had 2-3 more bleeding/spotting days, and a shorter length of bleeding/spotting-free intervals in each period. 63.7%, 41.4% and 60.6% of subjects using Mesigyna, Cyclofem and Injectable No. 1, respectively, had bleeding patterns similar to their untreated patterns in the first 90-day period. The percentages increased to 82.2% 67.8% and 75.0% in the fourth 90-day period. A total of 1815 diaries for Mesigyna and 1802 for Cyclofem were analyzed for more in depth comparison of these two methods. The number of bleeding/spotting days over four periods showed little difference between the two group, but there were more spotting days and there was greater individual variability among Cyclofem users.(ABSTRACT TRUNCATED AT 250 WORDS)

1 alpha, 25-Dihydroxyvitamin D3 decreased ICAM-1 and ELAM-1 expressions on pulmonary microvascular endothelial cells and neutrophil motivation

Preincubation of pulmonary microvascular endothelial cells (PMVECs) with platelet activating factor (PAF) for 3.5 h increased the adhesion rate of polymorphonuclear leukocytes (PMNs) to PMVECs from 57.3 to 72.8% (P < 0.01). Coincubations of 1 alpha, 25-dihydroxyvitamin D3 (VD) or MC903 (VD analog) decreased the ability of PAF to increase PMN-PMVEC adhesion rate significantly. Preincubation of PMNs with PAF also increased PMN-PMVEC adhesion rate. Coincubation of VD but not MC903 blocked PAF-induced adherence of PMNs to PMVECs. Both VD and MC903 decreased PAF-increased expression of ICAM-1 on PMVECs, PMN chemotaxis to zymosan activated serum and histamine, and PMN aggregation induced by PAF significantly. VD but not MC903 decreased the expression of ELAM-1 on PMVECs. VD and MC903 did not affect PAF-induced release of acid phosphatase from PMNs. The results suggest that VD may be a good drug to inhibit PMN motivation by acting on both ECs and PMNs.

[Effect of electroacupuncture on gastric acid secretion and gut hormones]

21 patients with mild type of chronic superficial gastritis were selected in this study. The effect of electroacupuncture in Zhongwan (RM12), Neiguan (P6) and Sanyinjiao (Sp6) on gastric acid secretion, serum gastrin, plasma somatostatin, plasma motilin concentration and erythrocyte acetylcholinesterase (AchE) activity were observed. The results were as follows: There were significant decreases in gastric acid output, serum gastrin concentration and AchE activity (P < 0.05), but no significant changes in plasma somatostatin and motilin concentration (P > 0.05) after simultaneous electroacupuncture in Zhongwan, Neiguan and Sanyinjiao.

Activity of DMP 840, a new bis-naphthalimide, on primary human tumor colony-forming units

BACKGROUND

DMP 840 ((R,R)-2,2'-[1,2-ethanediylbis[imino(1-methyl-2,1-ethanediyl)]]- bis[5-nitro-1H-benz[de]-iso[quinoline-1,3(2H)-dione]dimethane- sulfonate; NSC-D640430) is one in a series of bis-naphthalimides that binds DNA with high affinity and has sequence specificity to multiple G and C bases. It is also a potent inhibitor of RNA synthesis. DMP 840 has been selected for clinical evaluation on the basis of a broad spectrum of activity (including cures) in human tumors in murine models.

PURPOSE

We evaluated DMP 840 in a human tumor clonogenic assay to estimate what plasma concentrations may be necessary for clinical cytotoxic activity and to determine what types of tumors potentially might be primary targets for initial phase II studies.

METHODS

A soft-agar cloning system assay was used to determine the in vitro effects of DMP 840 against cells from biopsy specimens of colorectal, breast, lung ovarian, renal cell, stomach, and bladder cancers and from other tumor types. A total of 260 human tumor specimens were exposed continuously during the assay to DMP 840; 103 were assessable (20 colonies or more on control plates and 30% or less survival for the positive control). An in vitro response was defined as at least a 50% decrease in tumor colony formation resulting from drug exposure compared with controls.

RESULTS

In vitro responses were seen in 10% (one of 10), 54% (55 of 101), 80% (82 of 103), and 89% (82 of 92) of specimens tested at 0.01, 0.1, 1.0, and 10.0 micrograms/mL of DMP 840, respectively. At a concentration of 0.1 microgram/mL, specific activity was seen against melanoma (80%) and against renal cell (80%), ovarian (63%), breast (54%), non-small-cell lung (42%), and colorectal cancers (33%). DMP 840 demonstrated activity in tumor specimens resistant in vitro to methotrexate (88%), doxorubicin (58%), platinum (57%), cyclophosphamide (53%), vinblastine (53%), etoposide (53%), fluorouracil (37%), and paclitaxel (36%).

CONCLUSIONS

At in vitro concentrations of 0.1 microgram/mL as a continuous exposure, DMP 840 has activity against a variety of human tumors, including a subgroup resistant in vitro to standard antineoplastic agents.

IMPLICATIONS

Further clinical development of DMP 840 is warranted.

The topography of the furcation entrance in Chinese molars. Furcation entrance dimensions

The purpose of the present study was to document the furcation entrance dimensions (FEDs) of the maxillary and mandibular 1st and 2nd molars and relate them to the choice of periodontal therapy. Study samples consisted of 89 maxillary molars (49 1st and 40 2nd molars) and 93 mandibular molars (50 1st and 43 2nd molars). All the FEDs of the molars were examined and measured under a stereomicroscope at 2.5 x equipped with a Bioscan OPTIMAS Image Analyzer (BOIA). The results may be summarized as follows. (1) The mean FEDs in the buccal, distal and mesial furcations of maxillary 1st and 2nd molars were 0.74 mm, 0.99 mm and 1.04 mm in the 1st molars, and 0.63 mm, 0.67 mm, 0.90 mm in the 2nd molars, respectively. In the buccal and lingual furcations of mandibular 1st and 2nd molars, they measured 0.88 mm and 0.81 mm, and 0.73 mm and 0.71 mm, respectively. (2) The %s of FEDs of 0.56 mm or less (the tip width of a Cavitron tip being 0.56 mm) in the buccal, distal and mesial furcations of maxillary 1st and 2nd molars, accounted for 32%, 8% and 6% of 1st molars, and 40%, 40% and 18% of 2nd molars. In the buccal and lingual areas of mandibular 1st and 2nd molars, they accounted for 16% and 26%, and 35% and 33% of the furcations, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Phospholipase C inhibitors: a new class of cytotoxic agents

A series of nitrocoumarin and nitrochromene derivatives have been prepared and shown to inhibit the phosphatidylinositol-specific phospholipase C(PLC)(IC50 < 10 micrograms/mL) isolated from human melanoma. The inhibition of PLC by nitrocoumarin 4a was time-dependent and irreversible. The inhibition of PLC was shown to interfere with inositide metabolism in whole cells (IC50 = 4 micrograms/mL) in a manner consistent with their proposed mode of activity. Finally, the compounds were shown to be growth inhibitory to cultured melanoma cells (ID50 = 2 micrograms/mL), suggesting that PLC may be an attractive new target for chemotherapeutic intervention.

Three drugs inhibit phospholipase A2-induced high permeability of endothelial monolayers

The permeability of aortic endothelial monolayers to fluid and albumin increased 13.5 and 16.1 times respectively after pretreatment with phospholipase A2 (PLA2, 100 U.ml-1) for 30 min. 1-(p-Chlorobenzoyl)-5-methylindole-3-acetic acid (1.16 mmol.L-1), SRI 63-441 (30 nmol.L-1), and 1,25-dihydroxycholecalciferol (0.1 mumol.L-1) decreased PLA2-induced high permeability. PLA2 did not damage the endothelial cells significantly. Our results indicate that the action of PLA2 to increase the permeability of endothelial monolayers is mainly due to PLA2-induced lipid mediators released from endothelial cells.

Effects of III-IV linker mutations on human heart Na+ channel inactivation gating

Na+ channel inactivation, a critical determinant of refractoriness, differs in cardiomyocytes and neurons. In rat brain type IIa (rB2a) Na+ channels, a critical residue in the cytoplasmic linker between domains III and IV regulates fast inactivation such that a Phe-->Gln substitution (F1489Q) inhibits inactivation by at least 85%. Since this residue is conserved in voltage-gated Na+ channels, we tested whether F1485Q, the analogous mutation in human heart (hH1a) Na+ channels, has a similar functional effect. We found that fast inactivation in wild-type (WT) channels expressed in Xenopus oocytes was complete within 15 milliseconds at a test potential of 0 mV, and its time course was biexponential with time constants of 0.4 and 2 milliseconds. But in contrast to rB2a, the FQ mutation inhibited inactivation by < 50% and increased mean single-channel open time by only twofold. Residual fast inactivation was monoexponential, with a time constant similar to that of the slower phase of normal inactivation (2 milliseconds). In the mutant channels, unlike WT, null tracings were absent at holding potentials in the range of -140 to -120 mV, and the voltage range of steady-state inactivation coincided exactly with that of activation, suggesting that residual inactivation was tightly coupled to the open state. As in rB2a, simultaneous mutations of I1484Q and M1486Q, in addition to mutation F1485Q, completely inhibited fast inactivation. Our results show that in heart Na+ channels, the IFM cluster controls the stability of both open- and closed-channel inactivation in a manner qualitatively similar to that in the brain. Structural differences in the putative inactivation receptor may explain the distinct gating patterns in channel subtypes.

[Effect of Saussurea lappa on gastric functions]

The patients with chronic superficial gastritis were selected in the study. The variation in gastric acidity output, serum gastrin and plasma somatostatin concentration were observed during the Saussurea lappa decoction (SLD) perfusion into the stomach. There was no significant changes in acidity output, serum gastrin and plasma somatostatin concentration after the perfusion of SLD (P > 0.05). Changes in gastric emptying and plasma motilin concentration were observed after oral administration of the SLD in 5 healthy volunteers. The time of gastric emptying was markedly shortened after oral administration of SLD (P < 0.01). A significant increase occurred in plasma motilin concentration at 30 min. after oral administration of SLD (P < 0.01). It revealed that SLD could accelerate the gastric emptying and increase the endogenous motilin release.

Mild intraischemic hypothermia suppresses consumption of endogenous antioxidants after temporary focal ischemia in rats

Oxidative damage by free radicals has been proposed as a mechanism of cerebral injury due to ischemia and reperfusion. Hypothermia protects against ischemic necrosis; however, its effect on oxidative stress has not been investigated. In this study, the effects of hypothermia on oxidative stress were studied by determining consumption of endogenous antioxidants after temporary focal ischemia in rats. Thirty-two Sprague-Dawley rats anesthetized with 1.5% isoflurane underwent 3 h of middle cerebral artery occlusion under hypothermic (33 degrees C) or normothermic (37 degrees C) conditions followed by 3 h of normothermic reperfusion. In the first study (n = 8 per group), intraischemic hypothermia suppressed the reduction of tissue concentrations of endogenous antioxidants, ascorbate (P < or = 0.05), and glutathione (P < or = 0.05) in ischemic cortex but not in caudoputamen. In a parallel study (n = 8 per group), hypothermia reduced tissue damage in ischemic frontoparietal cortex (P < or = 0.05), but not in caudoputamen. Laser-Doppler estimates of cortical blood flow showed that intraischemic hypothermia significantly attenuated early postischemic hyperperfusion (P < or = 0.01) and delayed postischemic hypoperfusion (P < or = 0.01). These results demonstrate that intraischemic mild hypothermia reduces oxidative stress and cell injury after prolonged focal ischemia followed by reperfusion. The reduction of oxidative stress by hypothermia may be related indirectly to attenuation of postischemic blood flow changes.

A study of primary- and re-infection with hepatitis C virus in blood transfusion recipients

A nested polymerase chain reaction was used to assess viraemia in blood transfusion recipients with no serological evidence of hepatitis C virus (HCV) infection (naive recipients) and in recipients with prior or existing HCV infection (infected recipients), who were transfused with HCV-positive blood. In 10 hepatitis cases in naive recipients, defined as primary infection, nine showed clinical hepatitis, and one was sub-clinical; the time between transfusion and elevation of alanine aminotransferase (ALT) levels was 15-60 days (37.9 +/- 13.9). All 10 naive recipients showed abnormal ALT, and 10/10 and 7/10 were persistently positive for anti-HCV and HCV-RNA, respectively, for more than 1 year. Similarly, in five cases in previously infected recipients, defined as re-infection, 4/5 showed clinical hepatitis, the time to elevation of ALT was 30-46 days (34.8 +/- 6.4), and 5/5 and 3/5 were persistently positive for anti-HCV and HCV-RNA, respectively, for more than 1 year. All five infected recipients showed abnormal ALT. In conclusion, there was no significant difference (P = 0.05) in the frequency of the markers of infection resulting from primary or re-infection with HCV, suggesting that primary infection fails to induce a protective immune response.

Pentoxifylline attenuates platelet activating factor-induced permeable edema in isolated perfused guinea pig lungs

The effect of pentoxifylline (Pen) on platelet activating factor (PAF)-induced pulmonary injury was studied in isolated guinea pig lungs perfused with cell-free Tris buffered Ringer solution. PAF (1.0 nmol.L-1) increased lung weight and pulmonary filtration coefficient (Kf), which indicated the formation of high permeable pulmonary edema. Pen (0.5 and 1.0 mmol.L-1) markedly attenuated the PAF-induced increment of lung weight and vascular permeability, but not the increment of pulmonary capillary pressure and venous resistance. There was no correlation between the severity of lung edema and the number of leukocytes in the perfusates. These results suggest that Pen has direct anti-permeability effect on pulmonary microvessels.

Rheumatoid factor in hepatitis B virus surface antigen positive patients

Rheumatoid factor (RF) is often found in the sera of patients with nonrheumatic diseases in comparison with normal individuals. We collected 95 healthy HBs antigen positive adults and 98 healthy HBs antigen negative adults. RF was present in 14.74% (14/95) of the HBs antigen positive group while it was present in 3.06% (3/98) of the HBs antigen negative group (p < 0.05). RF was positive in 15.38% (2/13) of the HBe antigen positive patients whereas it was positive in 14.63% (12/82) of the HBe antigen negative patients (p > 0.05). RF was found positive in 16.90% (12/71) of the anti-HBe antibody positive group while it was positive in 8.33% (2/24) of the anti-HBe antibody negative group (p > 0.05). We conclude that the positive rate of RF in HBs antigen positive patients is significantly higher than in that of HBs antigen negative patients. The incidence of RF positivity of the HBe antigen positive group is not higher than that of the HBe antigen negative group. The positive rate of RF in anti-HBe antibody positive group has a tendency to be higher than in that of their negative counterparts though there was no significant difference between them.

Evaluation of creatine analogues as a new class of anticancer agents using freshly explanted human tumor cells

BACKGROUND

The creatine kinase (CK) isozymes and their substrates, creatine and creatine phosphate, are believed to play a pivotal role in energy transduction in tissues with large, fluctuating energy demands, such as skeletal muscle, heart, and brain. This enzyme system may also be involved in the process of cellular transformation. Inhibition of tumor cell growth by creatine analogues has been observed and may be due to the ability of these analogues to impair cellular energy generation and utilization.

PURPOSE

An in vitro human tumor colony-forming assay was used to predict the clinical usefulness of creatine analogues as anticancer agents.

METHODS

The ability of cyclocreatine (1-carboxymethyl-2-iminoimidazolidine) and homocyclocreatine (1-carboxyethyl-2-iminoimidazolidine) to inhibit the growth of cells prepared from tumor samples taken directly from patients was evaluated by quantitative measurement of colony formation in a soft-agar cell culture assay system. Cyclocreatine was tested in this human tumor colony-forming assay at concentrations ranging from 0.067 to 20 mM against 128 tumor samples, 51 of which formed colonies in the assay and were considered evaluable. Homocyclocreatine was similarly tested at concentrations from 0.2 to 20 mM against 139 tumor samples; 54 were considered evaluable. The colony-forming assay was also used to compare the efficacy of the creatine analogues to representatives from the six major classes of standard chemotherapeutics (alkylating agents, antimetabolites, DNA intercalators, platinum compounds, topoisomerase inhibitors, and tubulin-interacting agents). In addition, CK levels were measured in 192 tumor samples that were taken from 166 patients.

RESULTS

Cyclocreatine and homocyclocreatine, at concentrations previously achieved in animal tissues (7-20 mM), had antitumor activity against 19% and 50%, respectively, of tumor samples that formed colonies in the assay. Cyclocreatine was effective against a subset of tumors sensitive to homocyclocreatine (P = .023; Fisher's exact test), which was the more potent creatine analogue in this assay (P < .001; McNemar's test). No relationships were seen between tumor samples sensitive to the creatine analogues and those sensitive to standard chemotherapeutics. Pairwise Wilcoxon rank sum tests indicated that CK activity was significantly higher in tumors with any growth in the colony assay compared with tumors that did not grow (P < .025).

CONCLUSIONS

The creatine analogues, cyclocreatine and homocyclocreatine, effectively reduced colony formation of freshly explanted human tumor cells. The mechanism of action or resistance to these compounds seems to differ from those of standard chemotherapeutics.

IMPLICATIONS

Creatine analogues that may alter the energy status of the tumor cell potentially represent promising new anticancer agents that function through a unique mechanism.

(R,R)-2,2'-[1,2-ethanediylbis[imino(1-methyl-2,1-ethanediyl)]]- bis[5-nitro-1H-benz[de]isoquinoline-1,3-(2H)-dione] dimethanesulfonate (DMP 840), a novel bis-naphthalimide with potent nonselective tumoricidal activity in vitro

(R,R)-2,2'-[1,2-ethanediylbis[imino(1-methyl-2,1-ethanediyl)]]- bis[5-nitro-1H-benz[de]isoquinoline-1,3-(2H)-dione] dimethanesulfonate (DMP 840), is a bis-naphthalimide anticancer tumoricidal agent currently in phase I clinical trials. DMP 840 exhibits curative activity in human tumor xenografts, where it shows selectivity for human solid tumors over murine leukemias. In contrast to the selectivity found for DMP 840 in vivo, DMP 840 exhibits potent antiproliferative activity in vitro against a variety of human and murine leukemia and solid tumor cell lines in culture, with inhibitory doses that reduce the number of treated cells to one half (IC50) values ranging from 2.3 to 53 nM. DMP 840 was growth inhibitory to three doxorubicin-resistant cell lines with IC50 values also in the nanomolar range. Clonogenic survival experiments showed that DMP 840 was equally cytotoxic to both exponentially growing and quiescent human clone A colon carcinoma cells. A 1-h incubation of DMP 840 (1.22-12 microM) caused 5-log cell kill in KB-3-1 human epidermoid carcinoma, clone A human colon carcinoma, and L1210 murine leukemia cell lines. The rapid cell killing by DMP 840 in clonogenic survival experiments and initial mechanism of action studies was consistent with a DNA-interactive mechanism for DMP 840 cytotoxicity. Mechanism of action studies in L1210 leukemia cells demonstrated that DMP 840 inhibited the incorporation of thymidine and uridine into DNA and RNA with IC50 values of 0.55 and 0.08 microM, respectively. DMP 840 produced DNA single-strand breaks in a dose-dependent manner. Double-strand breaks were not observed with DMP 840 treatment, even at higher concentrations of compound. Chinese hamster ovary (CHO) and P388 cells resistant to camptothecin and containing a mutant form of topoisomerase I were also used to evaluate whether DMP 840 was cross-resistant with agents active against topoisomerase I. While the CHOR line was 163-fold resistant to camptothecin, the CHOR line was only 1.7-fold resistant to DMP 840. In summary, DMP 840 is a DNA-interactive agent that demonstrates excellent antiproliferative activity in vitro against cultured tumor cells from both human and murine sources. Its mechanism of tumoricidal activity may be novel.

Reduction of vasogenic edema and infarction by MK-801 in rats after temporary focal cerebral ischemia

Blood-brain barrier permeability alteration, vasogenic brain edema, and infarction, which are more extensive after 3 hours of temporary middle cerebral artery occlusion (MCAO) and 3 hours of reperfusion than after 6 hours of permanent MCAO, develop in rats after prolonged focal cerebral ischemia. Protective effects of excitatory amino acid receptor antagonists have been previously demonstrated after temporary global ischemia and permanent focal ischemia in rats. The purpose of this study was to evaluate the effectiveness of MK-801, a noncompetitive N-methyl-D-aspartate receptor antagonist, in temporary middle cerebral artery occlusion in rats maintained at physiological levels of brain temperature. Rats were anesthetized with chloral hydrate (350 mg/kg, intraperitoneally). The MCAO of rats was occluded by cannulation with a nylon suture for 3 hours, followed by 3 hours of reperfusion accomplished by withdrawing the suture. MK-801 (1 mg/kg, intravenously) or saline (S) was injected immediately before the onset of MCAO. Water content (MK-801, n = 6; S, n = 6), Evans blue dye extravasation (MK-801, n = 6; S, n = 6), infarct volume (MK-801, n = 10; S, n = 10), histology (MK-801, n = 6; S, n = 6), and neurological deficit (MK-801, n = 15; S, n = 18) were measured at the end of 3 hours of reperfusion. Brain temperature was monitored during the experiment. The infarction area (measured by 2, 3, 5-triphenyltetrazolium chloride staining) was reduced (P < 0.001) in the MK-801-treated rats, as was the infarct volume and the severity of neuronal damage (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of DMP 840: a novel bis-naphthalimide cytotoxic agent with human solid tumor xenograft selectivity

DMP 840, a novel bis-naphthalimide, was evaluated for antitumor efficacy in several tumor models in mice. As measured by a tumor growth inhibition assay, i.v. administration of DMP 840 to athymic nude mice at doses at or below the maximum tolerated dose resulted in curative activity against four human solid tumor xenografts, MX-1 mammary carcinoma, CX-1 and DLD-2 colon adenocarcinomas, and LX-1 lung carcinoma, producing full or incomplete regressions and/or percent tumor growth inhibition of > or = 96%. The efficacy of DMP 840 in the models was dose dependent. The activity of DMP 840 against the human tumors surpassed that demonstrated by several clinically used and investigational anticancer agents. In long-term growth delay studies, DMP 840 induced full regressions in 20 of 20 mice bearing MX-1 tumors, and tumors in one-half of these mice remained regressed for over 5 months. In addition, DMP 840 was curative against exponentially growing DLD-2 tumors staged at 500 mg and MX-1 tumors staged at 1000 mg. The bis-naphthalimide was equally efficacious when administered i.v. or i.p. but was slightly less active after oral dosing. Against both the MX-1 mammary carcinoma and the DLD-2 colon adenocarcinoma, some measure of schedule dependence was observed; the optimum schedule was daily for 9 days. Against L1210 and P388 murine leukemias, DMP 840 demonstrated little or no activity and was inactive against B16 murine melanoma. Overall, these results suggest that DMP 840 may be a human solid tumor selective cytotoxic agent.

Human copper-zinc superoxide dismutase transgenic mice are highly resistant to reperfusion injury after focal cerebral ischemia

BACKGROUND AND PURPOSE

We have demonstrated in a previous study that superoxide radicals play a role in the pathogenesis of cerebral infarction, using a transgenic mouse model of distal middle cerebral artery occlusion, permanent ipsilateral cerebral carotid artery occlusion, and 1-hour contralateral cerebral carotid artery occlusion that produced infarction only in the cortex. However, the role of superoxide radicals in reperfusion injury in transgenic mice overexpressing superoxide dismutase (SOD) is unknown. Using a mouse model of intraluminal blockade of middle cerebral artery that produced both cortical and striatal infarction, we now further examined the role of superoxide radicals in ischemic cerebral infarction after reperfusion in transgenic mice overexpressing human CuZn-SOD activity.

METHODS

Transgenic mice of strain Tg HS/SF-218, carrying human SOD-1 genes, and nontransgenic littermates were anesthetized with chloral hydrate (350 mg/kg IP) and xylazine (4 mg/kg IP). Physiological parameters were maintained at a normal range using a 30% O2/70% N2O gas mixture inserted via an inhalation mask. Body temperature was maintained at 37 +/- 0.5 degrees C by using a heating pad throughout the studies. The middle cerebral artery occlusion was achieved with a 5-0 rounded nylon suture placed within the internal cerebral artery for 3 hours followed by the removal of the suture to allow reperfusion for another 3 hours. Cerebral infarct size in brain slices and infarct volume, neurological deficit, cortical blood flow, and glutathione levels were measured in both transgenic and nontransgenic mice.

RESULTS

Compared with the nontransgenic mice, the infarcted areas were significantly decreased in coronal slices from transgenic mice. The infarct volume (in cubic millimeters) was reduced by 26% in transgenic mice after ischemia and reperfusion. This decrease in the infarct volume in transgenic mice closely paralleled the reduced neurological deficits. Introduction of the suture to block blood supply to the middle cerebral artery territory produced a rapid decrease in the relative surface blood flow in the ipsilateral core and the peri-ischemic (penumbra) areas. There were no significant differences in the local cerebral blood flow in the ischemic core or the penumbra areas between the transgenic and nontransgenic groups. However, the level of reduced glutathione in the penumbra area was significantly higher in transgenic mice than in nontransgenic mice, whereas there was no difference in the reduced glutathione levels in the ischemic core between these two groups.

CONCLUSIONS

Our study demonstrated that superoxide radicals play a major role in the pathogenesis of cerebral infarction in reperfusion injury after a focal stroke. The reduction in infarct volume and neurological deficits is not dependent on the changes in cerebral blood flow but rather correlate with reduced oxidative stress in the ischemic brain tissue, which was indicated by the relatively high levels of endogenous reduced glutathione in transgenic mice.