Alterations in adriamycin efficacy by phenobarbital

Adriamycin dosage should be reduced in patients with impaired liver function, since adriamycin disposition is influenced by liver metabolism and biliary excretion. It follows that drugs that increase the metabolism or excretory capacity of the liver may decrease adriamycin concentrations to suboptimal values. Adriamycin metabolism was therefore studied in mice pretreated with phenobarbital (75 mg/kg i.v.) by injection. After an i.v. dose of adriamycin (30 mg/kg i.v.), plasma fluorescence due to drug and metabolites was less and disappeared at a greater rate in phenobarbital-pretreated mice than control animals. When extracted with chloroform: isoprophyl alcohol (1:1), the livers from the phenobarbital-pretreated group yielded a greater concentration of glycones. Experiments with liver microsomes confirmed that aglycone production occurred at a more rapid initial rate in phenobarbital-induced livers. No increase in aldoketo reductase (daunorubicin reductase) activity was noted. Phenobarbital-pretreated mice, inoculated i.p. with 1 million L1210 cells and then treated with adriamycin (6 mg/kg i.v.), had significantly lower survival than did controls (p less than 0.01). These findings show that phenobarbital affects the disposition of adriamycin by microsomal enzyme induction and suggest that drugs that induce microsomal enzymes should not be used concurrently with adriamycin if optimal drug efficacy is desired.     

Gas chromatographic-mass spectrometric identification and quantitation of benzyl alcohol in serum after derivatization with perfluorooctanoyl chloride: a new derivative

In the present study, the effect of melatonin on oxidative DNA damage induced by kainic acid (KA) treatment was investigated. 8-hydroxy-deoxyguanosine (8-OH-dG) is a main product of oxidatively damaged DNA and was used as the endpoint in these studies. The levels of 8-OH-dG were found to be elevated in the hippocampus and frontal cortex of rats treated with KA. These elevated levels were significantly reduced in animals that were co-treated with melatonin. Thus, there was no difference in 8-OH-dG levels in the brain of control rats compared to those treated with KA (10 mg/kg) plus melatonin (10 mg/kg). The levels of 8-OH-dG also increased in the liver of rats treated with KA. This rise in oxidatively damaged DNA was also prevented by melatonin administration. Melatonin's ability to reduce KA-induced increases in neural and hepatic 8-OH-dG levels presumably relates to its direct free radical scavenging ability and possibly to other antioxidative actions of melatonin.     

A molecular model of myelin oligodendrocyte glycoprotein

We evaluated the mechanism of the antitumor effects of mouse rIFN-gamma-inducing factor/IL-18 protein on the growth of mouse tumor cell lines in vivo. Mice received IL-18 before or after challenge with CL8-1, a mouse melanoma cell line. Both regimens significantly suppressed tumor growth and reduced the number of mice with growth of tumor from 60% (3/5) to 20% (1/5). Furthermore, IL-18 administered before and after tumor inoculation completely abrogated the establishment of CL8-1 in all animals. IL-18 administration also significantly suppressed the growth of MCA205, a sarcoma cell line, even when treatment was delayed to 7 days following tumor inoculation. Although IL-18/IL-12 combination therapy had the most significant and immediate antitumor effects, many mice so treated succumbed with markedly elevated serum IFN-gamma levels. The antitumor effects of IL-18 were abrogated almost completely when NK cells were eliminated using anti-asialo GM1 Ab administration, but only marginally impaired in IFN-gamma or IL-12 gene-disrupted mice. Immunohistochemical staining revealed that the number of the CD8+ T cells, but not CD4+ T cells, found at the tumor site was reduced in animals treated with IL-18. These results indicate that IL-18 has potent antitumor effects mediated by CD4+ T cells and NK cells, but in IFN-gamma- and IL-12-independent pathways.     

Hydroquinone increases the frequency of micronuclei in a dose-dependent manner in mouse bone marrow

The frequency of micronuclei (micronucleated polychromatic erythrocytes, MPCE and micronucleated normochromatic erythrocytes, MNCE) was studied at 12, 24 and 36 h post-treatment in the bone marrow of mice treated with 0, 0.78, 1.56, 3.125, 6.25, 12.5, 25, 50, 75 and 100 mg/kg body wt of hydroquinone (HQ). Treatment of mice with various doses of HQ resulted in a dose dependent increase in the frequency of both MPCE and MNCE at all the post-treatment time periods. The frequency of MPCE was significantly higher after administration of 3.125 mg/kg HQ at 24 h post-treatment, except 12 and 36 h, where a significant increase in the frequency of MPCE was observed only after administration of 6.25 mg/kg drug dose. Similarly, a significant increase in the frequency of MNCE was observed after 12.5 mg/kg HQ treatment at all the post-treatment time periods. The dose effect relationship between various HQ doses and MPCE and MNCE induction was linear and linear quadratic, respectively at all the post-treatment time periods. The PCE/NCE ratio declined in a dose dependent manner at all the post-treatment time periods and this decline was significant when compared to non-drug treated controls. The dose effect relationship was linear quadratic at all the post-treatment time periods studied.     

Thermoperiodic responses in insects and mites simulated with the double circadian oscillator clock

PURPOSE: To establish the pharmacodynamic relationships between drug biodistribution and drug toxicity/efficacy, a comprehensive preclinical evaluation of sphingomyelin/cholesterol (SM/chol) liposomal vincristine and unencapsulated vincristine in mice was undertaken. METHODS: Pharmaceutically acceptable formulations of unencapsulated vincristine and liposomal vincristine at drug/lipid ratios of 0.05 or 0.10 (wt/wt) were evaluated for toxicity, antitumor activity and pharmacokinetics following intravenous administration. RESULTS: Mice given liposomal vincristine at 2 mg/kg vincristine had concentrations of vincristine in blood and plasma at least two orders of magnitude greater then those achieved after an identical dose of unencapsulated drug. One day after administration of the liposomal vincristine, there were at least tenfold greater drug quantities, relative to unencapsulated vincristine, in the axillary lymph nodes, heart, inguinal lymph nodes, kidney, liver, skin, small intestines and spleen. Increased plasma and tissue exposure to vincristine as a result of encapsulation in SM/chol liposomes was not associated with increased drug toxicities. Treatment of the murine P388 ascitic tumor with a single intravenous dose of unencapsulated drug at 2, 3 and 4 mg/kg, initiated 1 day after tumor cell inoculation, resulted in a 33 to 38% increase in lifespan. In contrast, long-term survival rates of 50% or more were achieved in all groups treated with the SM/chol liposomal vincristine formulations at doses of 2, 3 and 4 mg/kg. At the 4 mg/kg dose, eight of ten and nine of ten animals survived past day 60 when treated with SM/chol liposomal vincristine prepared at the 0.05 and 0.1 drug/lipid ratios, respectively. CONCLUSIONS: Overall, increased and prolonged plasma concentrations of vincristine achieved by liposomal encapsulation were correlated with dramatically increased antitumor activity in comparison with the unencapsulated drug, but no correlations could be established between pharmacokinetic parameters and toxicity.     

Effect of liposomal methylprednisolone on heart allograft survival and immune function in rats

Liposomal methylprednisolone (L-MPL) applied in monotherapy prolonged cardiac allograft survival in rats in comparison with the same dosage regimen of drug in solution (Solu-Medrol). The most efficacious treatment consisted of a 2-mg/kg i.v. dose of L-MPL twice a week (group III), producing survival up to 30 days, followed by a 4-mg/kg/week dose of L-MPL (group IV) and a single 2-mg/kg dose of L-MPL (group II). Survival in animals receiving Solu-Medrol as a 2-mg/kg dose twice a week (group V) did not differ from untreated animals. Only daily 4-mg/kg doses of methylprednisolone (MPL) in solution (group VI) were as effective as group III. The concentrations of MPL in liver and spleen were detectable for 26 days after the last dose of L-MPL, showing tissue selective sequestration of drug. Treatment at these low doses did not suppress endogenous corticosterone determined 24 hr or later in plasma. The administration of steroid caused significant immunosuppression in most animals as measured by inhibition of splenocyte blastogenesis induced with phytohemagglutinin. Cellular immunity data did not differ significantly between groups, but alterations occurred at day 14 to 15 after surgery: CD3, CD4 and ratio CD4:CD8 subsets of cells showed minimum values; CD8, CD4CD8, CD25 and white blood cell counts were at maximum at this time. Slight but significant differences between Immunoglobulin M suppression in group II compared to group I or V were found, whereas Immunoglobulin G values were unchanged. The transplantation and treatment with steroid decreased the total body weight of animals but increased weights of internal organs, particularly spleen, similarly for all groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Safety of in vivo adenovirus-mediated thymidine kinase treatment of oral cancer

BACKGROUND: Adenovirus-mediated transfer of the herpes simplex virus thymidine kinase gene (tk) is one of the most effective gene therapy strategies for solid tumors in experimental animal studies. Foundational animal studies in an oral cancer model have demonstrated significant antitumor effects and improved animal survival using this treatment strategy. OBJECTIVE: To assess the safety of adenovirus-mediated transfer of the herpes simplex virus tk gene for the treatment of oral cancer. DESIGN: Oral tumors were established in C3H/HeJ mice and were treated with tk followed by systemic ganciclovir administration. Polymerase chain reaction amplification techniques were used to screen local surrounding tissues and distant organs for the presence of the adenoviral construct. Microscopic examination of the tissues was performed to determine the cytopathic effects of the vector. Blood samples were obtained from the animals to test for liver, renal, and bone marrow function after treatment. RESULTS: The adenoviral vector was present in the livers, lungs, and kidneys of animals treated with the maximal single injection dose of 2 x 10(9) plaque forming units (pfu). No vector was noted systemically after delivery of an equally effective low dose of 1 x 10(8) pfu. Microscopic examination revealed no cytopathic effects in distant organs despite the presence of vector. Results of liver and renal function tests revealed no differences between treated and control animals. There was no statistical difference in white blood cell count, hematocrit, or platelet count between animals treated with ganciclovir and control animals. CONCLUSIONS: Based on these results, the direct delivery of adenovirus-tk followed by ganciclovir administration appears both efficacious and safe in an animal model. However, serum evaluation for adenovirus vector and screening organ function studies should be included in human protocols using this gene therapy scheme.     

Phase I study of intravenous Lu-labeled CC49 murine monoclonal antibody in patients with advanced adenocarcinoma

CC49, a murine monoclonal antibody that recognizes the tumor-associated glycoprotein 72, was conjugated to the chemical chelate 1,4,7,10-tetraaza-1-(1-carboxy-3-(4-aminophenyl) propyl)-tris-4,7,10- ((carboxy)methyl)cyclododecane that had been labeled with a beta emitter, Lu. Preclinical studies had shown that Lu-labeled CC49 caused regression of human colon adenocarcinoma xenografts in nude mice. Patients with advanced adenocarcinoma who had failed standard treatment and whose tumors expressed the tumor-associated glycoprotein 72 antigen were eligible for treatment to determine the maximum tolerated dose of Lu-labeled CC49. The starting dose of Lu was 10 mCi/m2 given i.v. with the dose of CC49 held constant at 20 mg. Pharmacokinetic sampling and immunoscintigraphy were performed over the ensuing 3 weeks. The dose of radioactive Lu was escalated by 15 mCi/m2 for each successive dose level. Unexpected bone marrow toxicity developed in patients treated at the second dose level with 25 mCi/m2 Lu; two patients developed grade 4 thrombocytopenia, while the third patient developed grade 3 thrombocytopenia. Pharmacokinetic studies showed that the plasma half-life of the immunoconjugate was 67 h; whole-body retention, however, was prolonged with a biological half-life of 258 h. Serial gamma camera imaging localized known tumor in all patients, and also demonstrated prolonged Lu retention in the reticuloendothelial system (RES). Bone marrow dosimetry estimates ranged from 4 to 5 REMS/mCi Lu based on imaging and biopsy data. Analysis of bone marrow biopsies demonstrated that most of the Lu was localized in the cellular compartment and not in the bone. No antitumor responses were observed. Intravenous administration of 15 mCi/m2 Lu-labeled CC49 to previously treated advanced cancer patients was associated with acceptable hematological toxicity and was the maximum tolerated dose. However, prolonged retention of Lu in the RES, including the bone marrow, was observed and limited the dose of Lu that could be given. Additional studies are indicated to reduce RES uptake and retention of this immunoconjugate.     

Comparative intravenous toxicity of cisplatin solution and cisplatin encapsulated in long-circulating, pegylated liposomes in cynomolgus monkeys

The toxicity of cisplatin encapsulated in pegylated, long-circulating liposomes (SPI-077) was compared with nonliposomal cisplatin in male and female cynomolgus monkeys (n = 2-4 per sex per group) treated with intravenous infusions of 2.5 or 25 mg/kg SPI-077, 2.5 mg/kg cisplatin, placebo liposomes, or saline once every 3 weeks for total of five treatments. All animals survived until scheduled necropsy at 3 days after the final treatment or after a treatment-free 4-week recovery period. Emesis occurred after each treatment in all cisplatin-treated monkeys, but only once in one monkey treated with high-dose SPI-077. Dose-related mild decreases in red blood cell (RBC) count, hemoglobin, and hematocrit to or slightly below low normal range occurred in the high-dose SPI-077 and placebo liposome treatment groups after each treatment, with partial to complete recovery between treatments and no signs of correlating bone marrow toxicity. Decreases were similar in cisplatin-treated monkeys, but resolved only slightly between treatments and after the end of treatment (continuing to decrease in females) and were accompanied by bone marrow hypocellularity. Indirect, but not direct, bilirubin levels were cyclically elevated in the high-dose SPI-077 and placebo-treated animals, but not in the other treatment groups. Levels had either fully resolved or were near baseline and/or saline group values prior to the next treatment. Serum cholesterol levels were cyclically increased in SPI-077- and placebo liposome-treated animals, and minimally increased numbers of foam cells were seen in the liver, spleen, kidney, and other organs; both were considered related to the lipid dose administered. Cisplatin-treated monkeys exhibited sensory polyneuropathy and moderate irreversible toxic tubular nephrosis, but no neuropathy or nephrotoxicity was seen in either SPI-077 treatment group. Microscopically, treatment-related cell death was seen in dorsal root ganglia (DRG), affecting 15% of the cells in cisplatin-treated animals, compared to 8 and 12% in the low- and high-dose SPI-077 treatment groups. Neither drug was ototoxic. In summary, repeated administration of SPI-077 produced minimal, reversible effects related to the lipid dose administered, mostly limited to the 25 mg/kg dose group. The most notable effects in this group were cyclical decreases in hematology parameters thought to be related to increased recycling of a small fraction of RBCs and limited cell death in the DRG in the absence of any neurophysiological changes. Animals treated with a 10-fold lower dose of cisplatin (2.5 mg/kg), in contrast, exhibited myelo-, nephro-, and neurotoxicity, including sensory neuropathy, and were emetic after every dose. The SPI-077 liposomal formulation of cisplatin may provide a less toxic alternative to standard cisplatin solution.     

Restriction endonuclease analysis and plasmid profiling of Actinobacillus pleuropneumoniae serotype 7 strains

The use of adriamycin, an antitumour agent, is restricted by its cardiotoxicity. The objective of this study was to investigate the role of mitochondrial Ca2+ in adriamycin-induced cardiotoxicity and the effect of either cyclosporin A (CsA) or tacrolimus (FK506) on that cardiotoxicity. A single dose of adriamycin (10 mg/kg body weight) caused myocardial damage that was manifested by elevation of serum enzymes, glutamate-oxaloacetate transaminase (GOT), glutamate-pyruvate transaminase (GPT), lactate dehydrogenase isoenzyme (LDH-iso) and creatine phosphokinase isoenzyme (CPK2-MB). The permeability of heart inner mitochondrial membrane of adriamycin-treated rats was examined. Tetraphenyl phosphonium ion (TPP+) uptake, estimated with a TPP+-sensitive electrode was used to monitor changes in heart inner mitochondrial membrane potential. Ca2+ efflux was measured spectrophotometrically with the Ca2+ indicator arsenazo III. The ability of heart mitochondria isolated from adriamycin treated rats to retain accumulated Ca2+ or TPP+ was sharply reduced. The increase of diagnostic serum enzymes and isoenzymes and the reduced ability to retain Ca2+ or TPP+ by heart mitochondria were restored to almost the normal levels when (500 microg/kg body weight) of CsA or FK506 were injected with adriamycin. The data suggested that adriamycin cardiotoxicity might be due to the increase of inner membrane permeability in heart mitochondria as a result of increasing the sensitivity of a Ca2+ dependent-pore of the inner mitochondrial membrane to calcium, leading to dissipation of membrane potential and release of pre-accumulated Ca2+. Suitable antagonists of Ca2+-dependent pore formation such as CsA or FK506 may improve heart tolerance to adriamycin.     

Response of mosquitoes (Diptera: Culicidae) to carbon dioxide and octenol in Egypt

The radioprotective effect of the leaf extract of Ocimum sanctum (OE) in combination with WR-2721 (WR) was investigated on mouse bone marrow. Adult Swiss mice were injected intraperitoneally (i.p.) with OE (10 mg/kg on 5 consecutive days), or 100-400 mg/kg WR (single dose) or combination of the two or double-distilled water (DDW) and whole-body exposed to 4.5 Gy gamma-irradiation (RT). Metaphase plates were prepared from femur bone marrow on days 1, 2, 7 and 14 post-treatment and chromosomal aberrations were scored. The maximum number of aberrant cells was observed at 24 h after irradiation in all the groups. However, pretreatment with OE or WR individually resulted in a significant decrease in aberrant cells as well as different types of aberrations. The combination of the two further enhanced this effect; resulting in a 2-fold increase in the protection factor (PF = 6.68) compared to 400 mg/kg WR alone. The percent aberrant cells decreased linear-quadratically with WR dose when given individually, while in the OE + WR pretreatment animals the values showed a linear dose response. Combination of OE with WR doses above 200 mg/kg completely eliminated rings, polyploidy and pulverization of chromosomes. Percent aberrant cells decreased with time in all groups, though the values remained higher than normal even on day 14 in the RT alone as well as those treated with single agent + RT. WR doses above 200 mg/kg before RT resulted in significantly higher frequency of aberrant cells compared to RT and OE + RT groups on day 14, suggesting delayed WR toxicity; but combination of OE with WR brought down these values to normal level, indicating that OE combination, in addition to enhancing WR protection, may also act as a detoxifier. The protective effect of OE and WR is also reflected in the enhancement of bone marrow CFU survival. Both OE and WR possessed significant free radical scavenging activity in vitro. The combination of the two further enhanced this effect, suggesting that the enhanced free radical scavenging activity by combining the two protectors results in the higher bone marrow cell protection. The significant elevation in chromosome protection obtained by combining OE with WR, with reduction in the latter's toxicity at higher doses, suggests that the combination may have promise for radioprotection in humans.     

Docetaxel chronopharmacology in mice

Docetaxel tolerance and antitumor efficacy could be enhanced if drug administration was adapted to circadian rhythms. This hypothesis was investigated in seven experiments involving a total of 626 male B6D2F1 mice, synchronized with an alternation of 12 h of light and 12 h of darkness (12:12), after i.v. administration of docetaxel. In experiment (Exp) 1, the drug was given once a week (wk) for 6 wks (20 mg/kg/wk) or for 5 wks (30 mg/kg/wk) at one of six circadian times, during light when mice were resting [3, 7, or 11 hours after light onset (HALO)], or during darkness, when mice were active (15, 19, or 23 HALO). Endpoints were survival and body weight change. In Exp 2 and 3, docetaxel (30 mg/kg/wk) was administered twice, 1 wk apart, at one of four circadian stages (7, 11, 19, or 23 HALO). Endpoints were hematological and intestinal toxicities. In Exp 4, circadian changes in cell cycle phase distribution and BCL-2 immunofluorescence were investigated in bone marrow as possible mechanisms of docetaxel tolerability rhythm. In Exp 5 to 7, docetaxel was administered to mice bearing measurable P03 pancreatic adenocarcinoma (270-370 mg), with tumor weight and survival as endpoints. Mice from Exp 5 and 6 received a weekly schedule of docetaxel at one of six circadian stages (20 or 30 mg/kg/wk at 3, 7, 11, 15, 19, or 23 HALO). In Exp 7, docetaxel (30 mg/kg) was given every 2 days (day 1, 3, 5 schedule) at 7, 11, 19, or 23 HALO. Docetaxel dosing in the second half of darkness (19 or 23 HALO) resulted in significantly worse toxicity than its administration during the light span (3, 7, or 11 HALO). The survival rate ranged from 56.3% in the mice treated at 23 HALO to 93.8 or 87.5% in those injected at 3 or 11 HALO, respectively (Exp 1, P < 0.01). Granulocytopenia at nadir was -49 +/- 14% at 7 HALO compared with -84 +/- 3% at 19 HALO (Exp 2 and 3, P < 0.029), and severe jejunal mucosa necrosis occurred in 5 of 8 mice treated at 23 HALO as opposed to 2 of 18 receiving docetaxel at 7, 11, or 19 HALO (Exp 2 and 3, P < 0.02). The time of least docetaxel toxicity corresponded to the circadian nadir in S or G2-M phase and to the circadian maximum in BCL-2 immunofluorescence in bone marrow. Docetaxel increased the median survival of tumor-bearing mice in a dose-dependent manner (controls: 24 days; 20 mg/kg weekly, 33 days; 30 mg/kg weekly or day 1, 3, 5 schedule, 44 or 46 days, respectively; Exp 5-7). Survival curves of treated mice differed significantly according to dosing time for each dose and schedule (P from log rank <0.003 to P < 0.03). In Exp 5 and 6, the percentage of increase in life span was largest if docetaxel was administered weekly at 7 HALO (20 mg/kg, 220%; 30 mg/kg, 372%) and lowest after docetaxel dosing at 19 HALO (80% with 20 mg/kg) or at 15 HALO (78% with 30 mg/kg). In Exp 7, (day 1, 3, 5 schedule), docetaxel was most active at 11 HALO (percentage increase in life span, 390%) and least active at 23 HALO (210%). Docetaxel tolerability and antitumor efficacy were simultaneously enhanced by drug dosing in the light span, when mice were resting. Mechanisms underlying the tolerability rhythm likely involved the circadian organization of cell cycle regulation. Docetaxel therapeutic index may be improved with an administration at night in cancer patients, when fewest bone marrow cells are in S or G2-M phase.     

Inhibition of nitric oxide interrupts the accumulation of CD8+ T cells surrounding Plasmodium berghei-infected hepatocytes

The elimination of liver-stage malaria parasites by nitric oxide (NO)-producing hepatocytes is regulated by T cells. Both CD8+ and CD4+ T cells, which surround infected hepatocytes, are evident by 24 h after sporozoite challenge in Brown Norway rats previously immunized with irradiated Plasmodium berghei sporozoites. While the number of CD4+ T cells remained the same beyond 24 h postchallenge, the number of CD8+ T cells increased three- and sixfold by 31 and 44 h, respectively. This increase in the number of CD8+ T cells correlated with a decrease in the number of intrahepatic parasites. In immunized rats, intrahepatic parasites were reduced in number by 31 h after sporozoite challenge and cleared from the liver by 44 h, as visualized by P. berghei-specific DNA in situ hybridization. If immunized rats were treated with aminoguanidine, a substrate inhibitor of NO synthase, at the time of challenge, liver-stage protection was blocked, as shown by the increase in parasite liver burden. Further histological examination of infected livers from immunized animals treated with aminoguanidine revealed fewer and smaller cellular infiltrates surrounding the infected hepatocytes, and the number of CD8+ T cells that normally accumulate within the infiltrates was drastically reduced. Consequently, the infected hepatocytes were not cleared from the liver. We hypothesize that the early production of NO may promote the influx and/or enhance local proliferation of malaria parasite-specific CD8+ T cells or a CD8+ T-cell subset which is required for parasite clearance.     

Peripheral morphine administration blocks the development of hyperalgesia and allodynia after bone damage in the rat

BACKGROUND: The current study aimed to assess whether local administration of morphine could block the development of hyperalgesia and allodynia in a rat model of osteotomy or bone damage. METHODS: Withdrawal responses to mechanical and thermal stimuli applied to the plantar surface of the hind paw were measured before and after bone damage. The bone was injured by drilling a 1-mm hole through the tibia during short-lasting general anesthesia. In separate groups of rats, the effects of administering morphine (20-80 microg), either into the marrow cavity or systemically, on the development of hyperalgesia and allodynia after bone damage were assessed. In an additional group of rats, a selective mu-opioid receptor antagonist, clocinnamox (0.15 mg), was administered into the marrow cavity before the administration of morphine (40 microg). RESULTS: In animals that received no drug treatment, hyperalgesia and allodynia peaked 2 h after injury. Injection of morphine (40 and 80 microg) into the marrow cavity immediately after bone injury prevented the development of hyperalgesia and allodynia. Clocinnamox (0.15 mg) injected into the marrow cavity before administration of morphine blocked the antihyperalgesic effect of morphine. CONCLUSION: This study shows that local application of a low dose of morphine effectively blocks the development of hyperalgesia and allodynia in a rat model of bone damage through mu-opioid receptor action. These findings provide further evidence that local application of morphine at the time of orthopedic surgery, bone graft, or bone marrow harvesting may reduce the amount of postoperative pain.     

Effect of melatonin on 1,2-dimethylhydrazine-induced intestinal tumors in rats

Fifteen doses of 21 mg/kg body weight of 1,2-dimethylhydrazine (DMH) were injected into 48 female rats at one-week intervals. Controls included 25 animals while 23 received 20 mg/l of melatonin with drinking water, 5 times a week, at night-time, for 6 months, beginning from the day of the first injection. Although malignancies of large bowel developed in all animals, multiple tumors in the melatonin group were significantly fewer than in the rats treated with DMH alone (6,0 and 9,9 respectively; p < 0,001). Similarly, melatonin treatment was followed by a significantly lower frequency of tumor development in the ascending colon as well as fewer multiple neoplasms of the ascending and descending colon. Melatonin was also shown to inhibit carcinogenesis in the small intestine. It is suggested that the antitumor effects of melatonin is due to its antioxidant properties.     

Amphetamine-induced withdrawal responding: effects of repeated drug administration

The first purpose of this research was to assess withdrawal haloperidol-appropriate lever responding 24 h after a single administration of 0.35, 0.75, and 1.00 mg/kg amphetamine. Rats were trained to discriminate among 0.35 mg/kg amphetamine (AM), distilled water (DW), and 0.033 mg/kg haloperidol (HA) in a three-lever drug discrimination task. An increase in HA-appropriate lever responding occurred following the 1.00 mg/kg dose of AM but not after either of the lower doses. The second purpose was to determine the effect of repeated administration of 0.75 mg/kg AM. Two groups of animals were given five administrations of drug, one at an interdose interval (IDI) of 24 h and the other at an IDI of 48 h. Control animals were given injections of DW. Increased HA-appropriate lever responding occurred in both of the AM-treated groups. The magnitude of this effect tended to be less in the 48-h IDI group. Thus, even though HA-lever responding was not evident 24 h after a single administration of 0.75 mg/kg AM, it was produced by repeated administration of this dose, even at 48-h intervals.     

Interleukin-2 inhibits graft-versus-host disease-promoting activity of CD4+ cells while preserving CD4- and CD8-mediated graft-versus-leukemia effects

We have recently shown that a short course of high-dose interleukin-2 (IL-2) can markedly inhibit the graft-versus-host disease (GVHD)-promoting activity of donor CD4+ T cells. The difficulty in dissociating GVHD-promoting from graft-versus-leukemia (GVL) effects of alloreactive donor T cells currently prevents clinical bone marrow transplantation (BMT) from fulfilling its full potential. To test the capacity of IL-2 treatment to promote such a dissociation, we have developed a new murine transplantable acute myelogenous leukemia model using a class II major histocompatibility complex-positive BALB/c Moloney murine leukemia virus-induced promonocytic leukemia, 2B-4-2. BALB/c mice receiving 2.5 x 10(5) 2B-4-2 cells intravenously 1 week before irradiation and syngeneic BMT died from leukemia within 2 to 4 weeks after BMT. Administration of syngeneic spleen cells and/or a 2.5-day course of IL-2 treatment alone did not inhibit leukemic mortality. In contrast, administration of non-T-cell-depleted fully allogeneic B10 (H-2b) spleen cells and T-cell-depleted B10 marrow led to a significant delay in leukemic mortality in IL-2-treated mice. In these animals GVHD was inhibited by IL-2 treatment. GVL effects were mediated entirely by donor CD4+ and CD8+ T cells. Remarkably, IL-2 administration did not diminish the magnitude of the GVL effect of either T-cell subset. This was surprising, because CD4-mediated GVHD was inhibited in the same animals in which CD4-mediated GVL effects were not reduced by IL-2 treatment. These results suggest a novel mechanism by which GVHD and GVL effects of a single unprimed alloreactive T-cell subset can be dissociated; different CD4 activities promote GVHD and GVL effects, and the former, but not the latter activities are inhibited by treatment with IL-2.     

Mouse palatal width growth rates as an "at risk" factor in the development of cleft palate induced by hypervitaminosis A

In this study, we examined the therapeutic antitumor effect of cytotoxic T lymphocytes (CTL) generated against CD86-transfected mouse neuroblastoma C1300. We first generated the transfectant, CD86 + C1300, expressing a high level of mouse CD86 on the cell surface. While CD86 + C1300 cells were rejected in syngeneic A/J mice when inoculated subcutaneously, neither vaccination nor any therapeutic antitumor effect was obtained, implying that C1300 may be a poorly immunogenic tumor. However, in vitro stimulation of splenocytes from either C1300-bearing or CD86 + C1300-rejecting mice with CD86 + C1300 cells resulted in remarkable CTL activity against C1300 cells. The CTL activity induced by CD86 + C1300 was mediated by T cell receptor/CD3 and CD8 and was further enhanced by the addition of interleukin-2. Intravenous inoculation of C1300 cells led to multiple organ metastases including the liver, lung, kidney, ovary, lymph node and bone marrow. To examine the therapeutic effect of CTL in this metastasis model, CTL induced by parental or CD86 + C1300 cells were administrated into C1300-bearing mice. Adoptive transfer of CD86 + C1300-induced CTL resulted in marked elimination of multi-organ metastases and prolonged survival in almost all mice, 70% of which survived indefinitely. These results indicate that adoptive transfer of CTL induced by CD86-transfected tumor cells in vitro would be effective and useful for tumor immunotherapy against poorly immunogenic tumors.     

Clinical and MRI findings of the temporomandibular joint in relation to occlusion in young adults

Although considerable evidence suggests that carcinogenic polycyclic aromatic hydrocarbons are immunosuppressive compounds, limited information is available regarding precise effects of these agents on immune cells. In the present report, the effect of subchronic exposure to benzo[a]pyrene (B[a]P) on immune cells in bone marrow, thymus and spleen of B6C3F1 mice was investigated. B[a]P treatment was found to reduce thymic cellularity and also to significantly alter normal thymocyte differentiation, as indicated by expression of CD4 and CD8 cell-surface antigens. Exposure to B[a]P also reduced cellularity of the bone marrow, including decreased percentage and absolute number of CD45R+ B-lineage lymphocytes. Further, B[a]P treatment dramatically increased the percentage of CD44hi cells in bone marrow, while proportionately reducing CD44lo cells. These results may indicate CD44lo bone marrow cells, including prolymphocytic cells, represent sensitive targets of B[a]P. The spleens of treated mice were found deficient in both Thy 1.2+ T lymphocytes and CD45R+ B lymphocytes, effects that correlate well with the chemical-induced alterations observed in thymus and bone marrow, respectively.     

Comparison of the toxicity profiles of ISIS 1082 and ISIS 2105, phosphorothioate oligonucleotides, following subacute intradermal administration in Sprague-Dawley rats

The systemic toxicity of two phosphorothioate oligonucleotides specific for herpes simplex viruses (ISIS 1082) and human papiloma virus (ISIS 2105) were evaluated following repeated intradermal injections of vehicle control, 0.33, 2.17, or 21.7 mg/kg daily to Sprague-Dawley rats (10/sex/group) for 14 days. Animals were sacrificed 1 day after the last dose, except for a portion of the ISIS 1082-treated animals (5/sex/group) which were maintained for an additional 14-day recovery period. The profile of alterations noted for both compounds was very similar. Other than local signs of irritation at the site of injection, there were no clinical signs of toxicity or treatment-related mortality, but there was a slight decrease in body weight gain for the 21.7 mg/kg dose groups. Alterations in hematology parameters included dose-dependent thrombocytopenia and anemia. Alterations in serum chemistry parameters were suggestive of mild alterations in hepatic metabolism, with increases in liver transaminases and bilirubin, along with decreases in albumin and cholesterol. Both spleen and liver weights were significantly elevated in a dose-dependent fashion. Histopathological alterations noted in liver, kidney, lung, injection site skin, and spleen were characterized as perivascular and interstitial infiltrates of macrophages and monocytes. Additional microscopic alterations in the spleen included mild lymphoid hyperplasia (seen in lymph nodes as well), and extramedullary hematopoiesis. Treatment-related cytopenias were likely related to mild, focal hypocellularity in the bone marrow. Alterations in ISIS 1082-treated animals were only partially reversed following the 14-day treatment-free period. In conclusion, repeated intradermal administration of ISIS 1082 and ISIS 2105 produced a similar spectrum of toxicities, with liver, kidney, spleen, and bone marrow being identified as target tissues.