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Cocaine decreases self-control in rats: a preliminary report.

Cocaine abuse is often associated with behavior that takes into account short-term, but not long-term consequences. However, there has been no empirical research concerning the effects of cocaine on self-control (choice of a larger, more delayed reinforcer over a smaller, less delayed reinforcer). In the present research, when food-deprived rats repeatedly chose between a larger, more delayed food reinforcer and a smaller, less delayed food reinforcer, chronic intraperitoneal injections of 15 mg/kg cocaine (but not 10 mg/kg fluoxetine) decreased the rats' choices of the larger, more delayed reinforcer. Cocaine can decrease rats' self-control.

Animals↗

Interactions between aluminum and the actions and metabolism of vitamin D3 in the chick.

The effects of intraperitoneal injections of aluminum chloride were tested on the intestinal calcium absorption and bone calcium mobilization responses to vitamin D3 and 1,25(OH)2D3, as measured by bioassay in chicks. Aluminum at 5 mg/kg given 5 days before the bioassay in vitamin D-deficient chicks, partially blocked the intestinal calcium absorption response to low (0.65 and 3.2 nmol), but not to higher (32 nmol) doses of vitamin D3. The responses to all doses (0.32-2.1 nmol) of 1,25(OH)2D3 were partially blocked by aluminum treatment. Serum calcium values were elevated in vitamin D-deficient chicks by aluminum administration, but no consistent effects of the treatment on bone calcium mobilization in response to vitamin D3 or 1,25(OH)2D3 were noted. Aluminum treatment in vivo led to decreased 25-OH-D3-1-hydroxylase activity subsequently measured in renal homogenates; under a variety of conditions, no direct effect of aluminum on 25-OH-D3 metabolism by primary cultures of chick kidney cells was observed. The results suggest that the ability of the intestine to respond normally to 1,25(OH)2D3 may be compromised by exposure to high levels of aluminum and that the effect of this element on 25-OH-D3 metabolism observed in vivo may not be exerted by direct action on the renal cell.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

The nootropic properties of ginseng saponin Rb1 are linked to effects on anxiety.

Previous studies have shown that crude ginseng extracts enhance performance on shock-motivated tasks. Whether such performance enhancements are due to memory-enhancing (nootropic) properties of ginseng, or to other non-specific effects such as an influence on anxiety has not been determined. In the present study, we evaluated both the nootropic and anxiolytic effects of the ginseng saponin Rb1. In the first experiment, 80 five-day-old male chicks received intraperitoneal injections of 0, 0.25, 2.5 or 5.0 mg/kg Rb1. Performance on a visual discrimination task was evaluated 15 minutes, 24 and 72 hours later. Acquisition of a visual discrimination task was unaffected by drug treatment, but the number of errors was significantly reduced in the 0.25 mg/kg group during retention trials completed 24 and 72 hours after injection. Animals receiving higher dosages showed trends towards enhancement initially, but demonstrated impaired performance when tested 72 hours later. Rb1 had no effect on response rates or body weight. In the second experiment, 64 five-day-old male chicks received similar injections of Rb1 (0, 0.25, 2.5 or 5.0 mg/kg) and separation distress was evaluated 15 minutes, 24 and 72 hours later. Rb1 produced a change in separation distress that depended on the dose and environmental condition under which distress was recorded. These data suggest that Rb1 can improve memory for a visual discrimination task and that the nootropic effect may be related to changes in anxiety.

Animals↗

Differences in the incorporation of L- and DL-Amino acids into renal tubular cells. An autoradiographic study.

The cytoplasmic uptake of 3H-L-leucine and 3H-L-proline by hepatocytes and cells of the proximal and distal convoluted and of the collecting tubules of the kidney was compared with that of 3H-DL-leucine and 3H-DL-proline in an autoradiographic study. 34 male white Sprague-Dawley rats were killed 1, 2, 6, and 24 hours after the intraperitoneal injection of these amino acids. The rate of incorporation of 3H-L-leucine in the liver and in the renal tubules, as judged by the number of silver grains counted, was about twice that of 3H-L-proline. In the tubules of the kidney the intensity of labelling progressively declined from the proximal convoluted to the collecting tubules. When the two 3H-DL-amino acids were used, almost identical rates of incorporation were found in the liver as well as in the kidney. The only exception was the pars recta of the proximal tubule: Here there could be found an unusually high uptake of 3H-DL-proline. The values were not only higher than those found for the uptake of 3DL-leucine in this particular segment, but they also surpassed those due to 3H-DL-proline and 3DL-leucine in the other parts of the renal tubules, as well as in the liver. The conspicuously high labelling seen in the pars recta after the injection of 3H-DL-proline suggests that there is present in the cells of this segment a d-amino acid oxidase, which may be relatively specific for D-proline. The possibility is considered that this enzyme may participate in a detoxifying function of the pars recta.

Amino Acids↗

Effect of recombinant human GH and GHRH on plasma metabolite levels in rainbow trout (Oncorhynchus mykiss).

The aim of the present work was to study metabolic changes in rainbow trout treated with preparations of human recombinants of growth hormone (rhGH) and GH-releasing hormone (rhGHRH), by analysing time course variations in plasma metabolite levels. Trouts were given the hormones by intraperitoneal injection in a single dose (rhGH: 0.5microg/g b.w.; rhGHRH: 0.06microg/g b.w.) or as a weekly injection over a period of 4 weeks. The concentrations of glucose, lactate, free fatty acids and glycerol were determined in plasma immediately before injection and 1, 3, 6, 12, 24, 48 and 168 hours post-injection. Results indicate that glucose and lactate levels increase, while slight variations in free fatty acids was observed after the injection of rhGH and rhGHRH.

Animals↗

Behavioural changes related to olfactory mucosal metaplasia and bulbar glial fibrillary acidic protein (GFAP) induction in methylsulphonyl-dichlorobenzene-treated mice.

Methylsulphonyl-2,6-dichlorobenzene [2,6-(diCl-MeSO(2)-B)], and its 2,5-chlorinated isomer [2,5-(diCl-MeSO(2)-B)] bind firmly in the olfactory mucosa of mice. Both isomers are also selectively localised in the olfactory bulb. Persistent olfactory mucosal metaplasia is induced by 2,6-(diCl-MeSO(2)-B) whereas 2,5-(diCl-MeSO(2)-B) has no effects. Furthermore, a strong induction of glial fibrillary acidic protein (GFAP) restricted to the olfactory bulb has been reported in 2,6-(diCl-MeSO(2)-B)-treated mice. To explore whether these lesions give rise to early or long-lasting changes in behaviour, spontaneous motor activity and radial arm maze (RAM) learning were examined at 1, 2, 4 and 12 weeks following an intraperitoneal injection of a single low (32 mg/kg) or high (65 mg/kg) dose of 2,6-(diCl-MeSO(2)-B). 2,5-(DiCl-MeSO(2)-B) (65 mg/kg) was used as a negative control. Hyperactivity was observed in all treatment groups while deficits in the RAM performance was only seen in the 2,6-(diCl-MeSO(2)-B)-treated groups. Alterations in motor activity and impaired performance in the RAM-test induced by 2,6-(diCl-MeSO(2)-B) persisted up to 2 weeks in the low-dose group and 12 weeks in the high-dose group. The low-dose group consistently showed a less pronounced effect than the high-dose group. The 2,5-(diCl-MeSO(2)-B)-induced changes in motor activity declined rapidly and did not remain after 2 weeks. As determined by immunohistochemistry, 2,6-(diCl-MeSO(2)-B)-induced GFAP immunoreactivity was mainly confined to the glomerular layer of the olfactory bulb. We propose that the behavioural deficits caused by 2,6-(diCl-MeSO(2)-B) result from a primary loss of sensory neurons in the olfactory mucosa with consequent astrocyte proliferation in the glomerular layer of the olfactory bulb. A targeted uptake of metabolites into the olfactory bulb could also contribute to the GFAP induction and/or behaviour response.

Animals↗

Markers of experimental acute inflammation in the Wistar Han rat with particular reference to haptoglobin and C-reactive protein.

C-reactive protein (CRP), haptoglobin (Hp) and fibrinogen (Fbgn) are acute phase reactants (APRs), the blood levels of which increase during acute inflammation. However, although the levels of these APRs are used to monitor inflammation in man, their usefulness and sensitivity as markers of inflammation in rodents are less clear. We therefore wished to evaluate, in a comparative fashion, a prototype immunoassay for serum CRP, a commercial assay for serum Hp, and an automated assay for Fbgn, using a model of acute inflammation in the rat. Additionally, pro-inflammatory cytokines and serum protein fractions were also measured. The model of inflammation used was the intraperitoneal injection of Freund's complete adjuvant (FCA). In a concluding experiment, findings with Hp in the FCA rat model were validated in a toxicologically relevant study involving the induction of acute hepatic inflammation using the model hepatotoxicant carbon tetrachloride (CCl(4)). Female Wistar Han rats were treated with a single injection of FCA in a dose-response study (1.25-10.0 ml/kg, sampling at 36 h) and two time-course studies (over 40 h and 21 days). In a final experiment, rats were dosed with CCl(4) at 0.8 ml/kg and sampled over a 17-day period. In FCA and CCl(4) experiments, serum/plasma was prepared and tissues taken at autopsy for histological assessment (CCl(4) study only). In the dose-response study, serum CRP, Hp and plasma Fbgn were increased at all FCA dose levels at 36 h post-dosing. Serum alpha(2) and beta(1) globulin fractions were also increased, while albumin levels were decreased. In the 40-h time-course study, CRP levels peaked at 25-40 h post-dosing, to approximately 120% of control (as 100%). Hp levels increased to a maximum at 25 and 40 h post-dosing with values greater than 400% of control, and alpha(2) and beta(1) globulin fractions peaked at 30 and 40 h post-dosing to 221 and 187% of control, respectively. Increased serum interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) levels peaked at 20 h (11-fold) and 25 h (19-fold), respectively. In a 21-day time-course study, no increased CRP levels were measured despite elevated levels of Hp, which peaked at 36 h (approximately 7-fold above control), and remained elevated up to 21 days. IL-6 and IL-1beta levels peaked at 12 h (19-fold) and 24 h (28-fold), respectively. Liver histopathology of animals treated with CCl(4) showed centrilobular hepatocellular degeneration and necrosis (most significant at 36 h) with an inflammatory response (most significant at 48 h). Resolution of the lesion was complete by 4 days post-dosing. Serum alanine aminotransferase, aspartate aminotransferase and glutamate dehydrogenase levels peaked at 36 h post-dosing. Hp levels increased maximally at 48 h (426% of control). We conclude that serum CRP is a poor marker of acute inflammation in the rat in comparison with serum Hp and plasma Fbgn. Between Hp and Fbgn, serum Hp is shown to be the most sensitive and useful marker of acute inflammation.

Acute Disease↗

Cells in midline thalamus, central amygdala, and nucleus accumbens responding specifically to antipsychotic drugs.

RATIONALE: Determining brain regions in which neuroleptic drugs of different types produce similar effects, especially where these effects are not shared with drugs lacking antipsychotic efficacy, provides evidence as to how and where the clinical effects of neuroleptic drugs are mediated. OBJECTIVE: For this study, the pattern of expression of the protein Fos, a marker of cellular activation, was compared after administration of the typical neuroleptic haloperidol, the antipsychotic drug clozapine, and the atypical neuroleptic olanzapine, as well as the sedative drug diphenhydramine and the anxiolytic lorazepam. METHODS: Animals (Sprague-Dawley rats, three per cohort) received intraperitoneal injections of haloperidol (1 mg/kg), clozapine (20 mg/kg), olanzapine (5 mg/kg), diphenhydramine hydrochloride (1 mg/kg), lorazepam (5 mg/kg) or vehicle (2% lactic acid, 1 ml/kg). Two hours after drug administration, animals were killed. Patterns of activated cells were observed by immunohistochemistry for Fos-like antibodies in regions previously suggested as responding to all antipsychotic drugs, including nucleus accumbens, central amygdala, and central medial thalamus. Cells staining for Fos were counted by semi-automated methods. RESULTS. A very similar pattern and number of Fos positive cells in nucleus accumbens, central amygdala, and central medial thalamus followed administration of each antipsychotic drug. The numbers of apparently activated cells were much greater following antipsychotic drug administration than after vehicle, with differences between each drug and vehicle being highly statistically significant in each region. Lorazepam produced apparent activation of cells of the central amygdala similar in degree and location but not identical in distribution to that of antipsychotic drugs. Diphenhydramine produced no apparent activation of cells in any of the sites tested. CONCLUSION: Typical and atypical antipsychotic drugs shared a distinctive pattern of robust activation of cells in nucleus accumbens, central medial thalamus, and central amygdala. Antipsychotic drug-induced activation of amygdala was shared by lorazepam, but activation of thalamus and nucleus accumbens was much greater following antipsychotic drugs than following lorazepam. The pattern of activated cells may be relevant to the therapeutic actions of antipsychotic drugs.

Amygdala↗

Antidepressants differentially affect expression of complexin I and II RNA in rat hippocampus.

Disturbance of synaptic transmission is currently viewed as an important pathophysiological mechanism and therapeutic target of mood disorders. Amongst other lines of evidence this theory is based on human post-mortem investigations showing differential expression of complexins. In order to discriminate between molecular correlates of the disease itself and effects of psychotropic drugs given to patients, we performed an animal trial using subchronic antidepressant treatment. Cohorts of adult male Sprague-Dawley rats were treated over a period of 14 days with intraperitoneal injections of either saline (0.9%, n=8), desipramine (15 mg/kg, n=7), fluoxetine (10 mg/kg, n=8), or tranylcypromine (10 mg/kg, n=5). Brain slices were used for in situ hybridizations with 35S labelled RNA probes of the genes complexin I, complexin II and syntaxin 1 A, the SNARE complex protein interacting with the complexins, and assessed semi-quantitatively for region-specific expression levels. Expression of complexin I was induced only in habenular nuclei after treatment with fluoxetine. In contrast, complexin II was significantly induced by desipramine and tranylcypromine, but not fluoxetine, in several brain regions. All treatment groups, but most significantly fluoxetine-treated animals, showed higher expression levels of syntaxin 1A. Antidepressants differentially affect expression levels of complexin I and more prominently complexin II and syntaxin 1A. The induction of complexin II and syntaxin 1A might strengthen the synaptic transmission at axo-dendritic or axo-axonal synapses. Previous post-mortem findings reporting on downregulation of complexins cannot be explained as mere effects of psychotropic drug treatment.

Adaptor Proteins, Vesicular Transport↗

Effects of endocannabinoid neurotransmission modulators on brain stimulation reward.

RATIONALE: The endogenous cannabinoid system is responsive to the neurobiological actions of Delta9-tetrahydrocannabinol (THC) and other cannabinoid ligands. While numerous studies have focused on the behavioral and pharmacological effects of THC and cannabinoid agonists in experimental animals, most recent work focuses on compounds that modulate endocannabinoid neurotransmission. However, the relevant studies concerning the ability of endocannabinoid modulators to modify reward processes in experimental animals remain rather scarce. OBJECTIVES: The present study examined the effects of drugs modulating endocannabinoid neurotransmission on brain reward function using the rate-frequency curve shift paradigm of intracranial self-stimulation (ICSS). METHODS: Animals were implanted with electrodes into the medial forebrain bundle (MFB). After brain stimulation reward thresholds stabilized, rats received intraperitoneal injections of the fatty acid amide hydrolase (FAAH) inhibitors phenylmethylsulfonyl fluoride (PMSF) (0, 15, 30, and 60 mg/kg) and URB-597 (0, 0.3, 1, and 3 mg/kg) and the selective anandamide reuptake inhibitor OMDM-2 (0, 3, 10, and 30 mg/kg). RESULTS: The highest dose of URB-597 and OMDM-2 significantly increased the threshold frequency required for MFB ICSS, while PMSF increased the threshold frequency in all doses tested. The cannabinoid 1 (CB1) receptor antagonist SR141716A reversed the actions of URB-597 and OMDM-2, but not PMSF, without affecting reward thresholds by itself. CONCLUSIONS: These results indicate that under the present experimental conditions endocannabinoid modulators do not exhibit reinforcing properties, but rather have inhibitory influence on reward processes. The anhedonic effects of URB-597 and OMDM-2, but not PMSF, observed at the highest doses in this study are probably mediated through direct CB1 receptor stimulation.

Amidohydrolases↗

Involvement of group II metabotropic glutamate receptors in stress-induced behavioural sensitization.

RATIONALE: A short session of repeated foot shocks in rats causes long-lasting sensitization of behavioural, hormonal and autonomic responses to novel stressful challenges. The behavioural sensitization can be reduced by anxiolytics and mimics aspects of stress-induced changes in patients with post-traumatic stress disorder. OBJECTIVES: The aim of this study was to test the efficacy of a group II metabotropic glutamate receptor (mGluR) agonist and assess altered brain mGluR receptor expression in shock-sensitized rats. MATERIALS AND METHODS: Male Wistar rats were exposed to a 15-min session with ten 6-s foot shocks (preshocked). One and 2 weeks later, rats were intraperitoneally injected with the group II metabotropic glutamate receptor agonist (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate (APDC) or vehicle, and 30 min later exposed to 5 min of 85 dB noise. For in situ hybridization with probes for mGluR1, mGluR2, mGluR3 and mGluR5, preshocked and control rats were killed under basal conditions 2 weeks after foot shocks and their brains cryosectioned. RESULTS: APDC had no clear effect in controls, but dose-dependently reduced high immobility and increased low locomotion and rearing seen in preshocked rats to the levels of controls. mGluR3 expression was increased in the basolateral nucleus of the amygdala, and mGluR2 expression was increased in the agranular insular cortex of preshocked rats compared to controls. CONCLUSIONS: Shock-induced behavioural sensitization in rats is reduced by acute treatment with a group II metabotropic glutamate receptor agonist. This effect may depend on the increased expression of amygdala mGluR3, which could be hypothesized as an endogenous mechanism to counteract stress-induced neuronal sensitization.

Amygdala↗

Olpadronate prevents the bone loss induced by cyclosporine in the rat.

The aim of the present in vivo experimental study was to investigate changes in bone turnover and bone mineral density (BMD) induced by cyclosporine (CsA) administration. The effectiveness of olpadronate (OPD) in preventing bone loss associated with CsA treatment was also evaluated. Forty male Sprague-Dawley rats (approximately 5 months old) were treated as follows: Group I: CsA+OPD vehicles (control); Group II: CsA 15 mg/kg + OPD vehicle; Group III: CsA 15 mg/kg + 4 ug OPD/100g rat; Group IV: CsA 15 mg/kg + 8 ug OPD/100g rat; Group V: CsA 15 mg/kg + 16 ug OPD/100g rat. CsA was administered by daily oral gavage and OPD by intraperitoneal injection once a week. Serum bone-alkaline phosphatase (b-ALP) and urinary deoxypyridinoline (DPyr) were measured on days 0, 14 and 30. Total skeleton, femur, lumbar spine, proximal, and middle tibia BMDs were measured on days 0 and 30. No significant differences were found between the CsA and the control groups as regards serum bALP levels, on days 14 and 30. CsA+OPD treated rats presented a transient increment in serum b-ALP on day 14 and a significantly lower level on day 30 compared to the control and CsA groups (P < 0.05). On days 14 and 30, DPyr excretion increased in the CsA group compared to control animals (P < 0.05). The three studied doses of OPD induced a significant decrease in DPyr excretion in the CsA group on days 14 and 30 (P < 0.05). Group V (receiving the highest dose of OPD) presented a significantly lower level of DPyr compared to the other two OPD-treated groups (P < 0.05). On day 30, the CsA group presented a significant reduction in proximal tibia, spine and whole femur BMDs (P < 0.05) compared to controls. On day 30, OPD treatment increased BMD of all the studied areas in CsA rats. Proximal tibia BMD of group V reached significantly higher values than the other studied OPD groups (P < 0.05). In summary, this study suggests that CsA-induced high bone resorption and trabecular bone loss is prevented by cotreatment with OPD. Moreover, it encourages the possible use of OPD to treat patients receiving CsA as immunosuppressive therapy.

Absorptiometry, Photon↗

Influence of interferon-alpha2b (IFN-alpha2b) on the prevention of locally advanced bladder carcinoma in mice.

In the model of chemically induced bladder carcinoma in mice following application of betahydroxylbutylnitrosamine (BBN) we could not detect a therapeutic influence of systemic treatment with intraperitoneal injection of interferon-alpha2b (10x3x10(5) IU IFN-alpha2b) on the rate of locally advanced bladder carcinoma (IFN-alpha2b 37% versus control 41%) nor on the development of tumor precursors (severe dysplasia 100% in both groups).

Animals↗

Physiological, growth, and immune responses of Japanese quail chicks to the multiple stressors of immunological challenge and lead shot.

Exposure to the combination of a contaminant and an immunological challenge during development may greatly increase the impact of either or both of these stressors on an individual. This study investigated the interacting effects of a nonpathogenic immunological challenge and lead shot exposure early in the development of a precocial species. Seventy-one quail (Coturnix coturnix japonica) chicks orally received either one #9 lead shot (0.05 g), four lead shots (0.2 g), or no lead at the age of 8 days. A third of each of these groups of chicks were intraperitoneally injected with either 0.075 ml of 10% chukar (Alectoris graeca) red blood cells (CRBCs), Newcastle disease virus (NDV), or a placebo oil vaccine at 13 and 35 days of age. There was no difference in the survival between any of the lead or antigen treatment groups. Lead concentrations in blood were greater for the lead-dosed groups on day 49 but not on day 128. Growth curves were approximated by Weibull functions; growth parameters did not differ between lead-treated and antigen-treated birds. CRBC antigen increases fluctuating asymmetry (FA) for primary feather five, while NDV reduced FA. Lead did not affect antibody production or cell-mediated immune response. White blood cell numbers increased 7 days after antigen injection on days 27 and 49 of age. Granulocyte numbers were significantly higher for the lead-treated quail than the control quail, and both antigen-treated groups had lower granulocyte numbers than control quail. The treatment groups of combining NDV and lead shot had an average plasma protein 14% lower than other groups. Lead shot in the highest of these doses lowered asymptotic weights, increased hematocrits, lowered plasma protein, and increased granulocyte numbers of quail.

Adaptation, Physiological↗

Mycophenolate mofetil does not suppress the graft-versus-leukemia effect or the activity of lymphokine-activated killer (LAK) cells in a murine model.

BACKGROUND: Graft-versus-leukemia (GVL) effect is an essential component in the course of allogeneic stem cell transplantation (SCT). However, both prevention and treatment of established graft-versus-host disease (GVHD), including with drugs such as cyclosporine, can suppress GVL effects. Mycophenolate mofetil (MMF) is becoming a standard of care in SCT recipients for better prevention of GVHD as well as for promoting stem cell engraftment. AIMS: To evaluate the effect of MMF, an immunosuppressive drug increasingly used for prevention of GVHD, on disease recurrence following SCT in a preclinical animal model. Since GVL effects may be also induced by alloreactive natural killer (NK) cells, the goal was to investigate the effects of MMF on the activity of lymphokine-activated killer (LAK) cells. METHODS: MMF was administered by daily intraperitoneal injection starting at day 1 post-SCT. Cytotoxic LAK activity was measured by 5-h 35S-release assay, and GVL was tested by the appearance of BCL1 leukemia in a semi-mismatched (C57BL/6 donors to [BALB/c x C57BL/6] F1 recipients) murine model. RESULTS: A dosage regimen of 28-200 mg/kg per day MMF had no negative effect on either cytotoxic LAK activity or GVL (as measured by finding of leukemic cells in recipient spleen by PCR or the appearance of clinical leukemia with adoptive transfer). CONCLUSIONS: These results suggest that MMF does not impair GVL effects or reduce LAK cell activity in mice.

Animals↗

Comparative nephrotoxicity of cisplatin and new octahedral Pt(IV) complexes.

PURPOSE: Previously, we have reported that the newly synthesized octahedral Pt(IV) compound, trans,cis-Pt(acetato)(2)Cl(2)(1,4-butanediamine), K101 and trans,cis-Pt(trifluoroacetato)(2)Cl(2)(1,4-butanediamine), K102 showed potent antitumor activities in vitro and in vivo. In order to compare the nephrotoxicity of the newly synthesized Pt(IV) complexes, K102 and K102 with cisplatin, we performed various tests. MATERIALS AND METHODS: We performed a single dose acute toxicity test for LD(50) values determination, biochemical assays in blood serum, acid phosphatase enzyme histochemistry and transmission electron microscopic studies in renal proximal tubular cells in mice in vivo. The route of drugs administration is intraperitoneal injection. RESULTS: In biochemical assays, the serum levels of BUN were significantly elevated at 6 h (p < 0.001), 1 day (p < 0.05) and 3 days (p < 0.001) after injection in cisplatin treated mice (6 mg/kg, single dose, i.p.). On the other hand, the serum levels of BUN were slightly elevated at 6 h (p < 0.01) only in K101 treated mice (8.2 mg/kg, single dose, i.p.), and were significantly raised at 6 h, 1 and 3 days (p < 0.05) after injection in K102 treated mice (6.2 mg/kg, single dose, i.p.). The higher serum BUN level in K102 treated mice is considered that K102 possesses more lipophilic fluoro group than acetyl group in K101. The values of creatinine and uric acid were similar in all groups. The ultrastructural morphological changes of K101- or K102-administrated mice were less remarkable than cisplatin-administrated mice. In acid phosphatase enzyme histochemistry, cisplatin treatment induced relevant changes in the distribution pattern of enzyme activity compared with K101 or K102 treatment at 7 days after injection. CONCLUSIONS: In conclusion, these results show that K101 is less nephrotoxic than cisplatin and a promising new platinum complex.

Acid Phosphatase↗

Antitumor and antimetastatic effects of interleukin 12.

Interleukin 12 (IL-12) has a pivotal role in controlling cell-mediated immunity through a number of important biological activities, such as secretion of interferon-gamma (IFN-gamma). In this review, we report our recent results regarding the antitumor and antimetastatic effects of IL-12. Five intraperitoneal injections of recombinant IL-12 (rIL-12) into mice bearing subcutaneous tumors (CSA1M fibrosarcoma) induced complete tumor regression, irrespective of whether tumors were at early or late stages of growth. Furthermore, IL-12-treated mice that had rejected the primary tumor exhibited complete resistance to rechallenge with the same tumor but did not reject a second syngeneic tumor. Immunohistochemical analyses following IL-12 treatment revealed that CD4+ and CD8+ T-cells had infiltrated the tumor. More importantly, IFN-gamma mRNA expression was observed in fresh tumor masses from tumor-bearing mice receiving IL-12 treatment. The importance of IFN-gamma was further demonstrated by the observation that systemic administration of anti-IFN-gamma monoclonal antibody prior to IL-12 treatment completely abrogated the antitumor effect of IL-12. We next investigated the ability of rIL-12 to modulate the outgrowth of metastatic tumor cells in an ovarian carcinoma (OV-HM) model. This aggressive tumor showed rapid growth of the primary tumor mass, a high incidence of metastases to the lung and lymph nodes, and invasion from the primary subcutaneous site into the peritoneal cavity. At approximately 1 month after tumor implantation, primary tumors in animals without palpable lymph nodes were surgically resected. When examined 2 months later, most animals had developed lymph node and lung metastases. In contrast, rIL-12 injections following tumor resection inhibited the development of metastases in both the lung and lymph nodes. Even in mice showing signs of lymph node metastases or invasion of the abdominal wall before primary tumor resection, rIL-12 administration following tumor resection prevented further invasion into the peritoneal cavity and metastatic tumor cell growth in the lung. Our results demonstrate that administration of rIL-12 to tumor-bearing mice results in tumor regression through mechanisms involving efficient IFN-gamma production by antitumor T-cells at tumor sites in situ and the establishment of a tumor-specific protective immune response. The results also indicate that IL-12 can induce a curative immune response in the face of an aggressive micrometastasizing tumor.

Animals↗

Mapping a chromosomal locus for valproic acid-induced exencephaly in mice.

Human neural tube defects (NTDs) are among the most common congenital defects. They have a highly heterogeneous etiology, and, in addition to those seen in association with genetic syndromes, there are also NTDs induced by pharmaceutical compounds in utero, such as the widely used anti-epileptic drug valproic acid (VPA). Although familial studies have suggested a genetic contribution to VPA-induced NTDs, this trait has not been adequately studied, nor have the responsible genetic factors been identified. We generated a series of mouse crosses and backcrosses using the highly inbred SWV/Fnn and C57BL/6J strains, in order to identify possible chromosomal loci contributing to VPA sensitivity. When exposed to a high dose of sodium VPA (600 mg/kg) via maternal intraperitoneal injection on gestational day E8.5, the fetuses manifested exencephaly in a strain-dependent manner. Our data show an autosomal recessive trait, plus a gender-related effect or an overall X-Chromosome (Chr) effect, as being primarily responsible for determining sensitivity to VPA-induced exencephaly. Genome scanning and further linkage analysis of 131 exencephalic backcross fetuses identified a major locus linked to D7Mit285 (p < 2 x 10(-6)), exceeding the threshold for significant linkage. These results suggest a major chromosomal locus associated with the sensitivity to VPA-induced exencephaly in mice.

Animals↗