Synthesis and antifeedant properties of N-benzoylphenylisoserinates of Lactarius sesquiterpenoid alcohols

The esterification of various sesquiterpenoid alcohols of Lactarius origin with N-benzoyl-[2R,3S]-phenylisoserine (side chain of Taxol) produced compounds whose antifeedant properties against storage pests Tribolium confusum, Trogoderma granarium and Sitophylus granarius were measured. The introduction of the taxol side chain in these molecules, in comparison to original compounds, moderately enhanced their antifeedant activities, as well as changed their selectivity of activity towards the test insects.

Significance of toxic interactions in medicolegal evidence. Complex fatal poisoning with drugs of abuse in the material of the Chair of Forensic Medicine, Collegium Medicum, Jagiellonian University in Kraków

The subject of the study was fatal complex poisonings with drugs of abuse in two young men. In the first case, postmortem investigation revealed cardiotoxic death as the result of an interaction between opiates, amphetamine derivatives and oxazepam. In the second case, death followed the administration of amphetamine derivatives and cocaine (xenobiotics known on the illicit drug market as "UFO"). Based on the toxicological postmortem analysis the authors discuss the interpretation of the results in the light of general problems of interactions taking place in toxicokinetic and toxicodynamic phases of intoxication processes.

Rise in zinc affinity for the NMDA receptor evoked by chronic imipramine is species-specific

Zinc and magnesium are potent inhibitors of the NMDA receptor complex. Previous reports demonstrated that both zinc and magnesium, like other NMDA receptor antagonists, exhibit antidepressant-like effects in rodent screening tests. Moreover, chronic treatment with antidepressants and electroconvulsive shock increase zinc concentration in the rat hippocampus. The present study examined the effect of tricyclic antidepressant, imipramine, on the potency of zinc and magnesium to inhibit [3H]MK-801 binding in the mouse and rat cerebral cortex and hippocampus. Chronic treatment with imipramine produced statistically significant increase in the potency of zinc to inhibit [3H]MK-801 binding in the mouse cerebral cortex but not in the hippocampus. However, this treatment neither influenced the zinc affinity in rat tissue nor magnesium affinity in tissue of both species. The present data indicate that, although imipramine-induced rise in zinc affinity to the NMDA receptor complex is in agreement with previously reported antidepressant-induced reduction of the NMDA receptor function, this effect is species-specific.

Clinical monitoring of hirudin and direct thrombin inhibitors

In addition to heparin, the standard medication for prophylaxis and therapy of thromboembolism, several other substances have been developed and tested for clinical use with the aim of decreasing or eliminating side effects. Most of all, hirudin, a direct antithrombin (AT), has proved to be effective. To define the therapeutic range and to avoid underdosage or overdosage, clinical monitoring is necessary. For monitoring of hirudin, thrombin time (TT) is not suited because of the missing linearity of the standard curve. Activated partial thromboplastin time (aPTT) can be used only in the lower hirudin level range, where the standard curve is quite linear. However, high and toxic hirudin levels cannot be determined using aPTT. Another drawback is a high variation in single measurements and in the normal value of patients. Methods using chromogenic substrates are suited for determination of hirudin in plasma but cannot be used at bedside. Especially for monitoring of hirudin, the ecarin clotting time (ECT) was developed. The standard curve is linear over the entire concentration range. There are no influences by other coagulation parameters or anticoagulants. For both acute clinical situations and long-term monitoring, this method capable of point-of-care therapy (POCT) will be the method of choice.

Twenty colloid cysts--comparison of endoscopic and microsurgical management

The management of colloid cyst remains controversial, evaluation of the competing methods seems to be necessary. We report on our experience with colloid cysts in the last decade: ten were managed solely endoscopically, 10 were resected microsurgically (9 via a transcortical/transventricular, 1 via a transcallosal approach). The outcome in the endoscopic group was excellent in 9 cases and unsatisfying in 1 case (recurrence). In the microsurgical group we achieved a good outcome in 5 of 10 cases, a fair outcome in 4 cases and 1 lethal outcome (caused by pulmonary embolism). Complications in the endoscopic group: one intraoperative bleeding, 1 stitch granuloma, 1 mispuncture of the ventricle, and 1 meningitis. Complications in the microsurgical group: 1 subdural effusion, 1 flap infection, 1 mild hemiparesis, 1 transient impairment of consciousness and 1 pulmonary embolism. Mean operative time and length of hospitalization of the endoscopic group were clearly shorter than in the microsurgical group: 91 min versus 267 min time of surgery, 5.1 days versus 18.9 days of hospitalization. Complete resection was achieved in 8 of 10 cases of microsurgery, and in 3 of 10 cases in endoscopy. Endoscopic management results in lower costs and superior patients' comfort. The reduced number of total resections in the endoscopic group may lead to a higher recurrence rate in long-term follow-up, which might be a serious disadvantage of endoscopy. However, more experience in the endoscopic techniques may result in a higher rate of total resection of colloid cysts.

Collagen IV promotes repair of renal cell physiological functions after toxicant injury

Collagen IV is found in the renal proximal tubular cell (RPTC) basement membrane and is a mediator of renal development and function. Pharmacological concentrations of L-ascorbic acid phosphate (AscP) promote the repair of physiological functions in RPTC sublethally injured by S-(1,2-dichlorovinyl)-L-cysteine (DCVC). We hypothesized that AscP promotes RPTC repair by stimulating collagen IV synthesis and/or deposition. RPTC exhibited increased synthesis but decreased deposition of collagen IV after DCVC exposure. In contrast, RPTC cultured in pharmacological concentrations of AscP maintained collagen IV deposition. The activity of prolyl hydroxylase was decreased in RPTC after DCVC injury, an effect that was partially attenuated in injured RPTC cultured in pharmacological concentrations of AscP. The addition of exogenous collagen IV to the culture media of DCVC-injured RPTC promoted the repair of mitochondrial function and Na(+)-K(+)-ATPase activity. However, neither collagen I, laminin, nor fibronectin promoted cell repair. These data demonstrate an association between AscP-stimulated deposition of collagen IV and exogenous collagen IV and repair of physiological functions, suggesting that collagen IV plays a specific role in RPTC repair after sublethal injury.

Evidence for a novel thrombopoietin signalling event: activation of protein kinase A in human megakaryoblastic CMK cells

Thrombopoietin (TPO) plays a crucial role in megakaryocyte development. TPO signalling, which is mediated by its receptor Mpl, includes Janus kinase, (JAK) signal transducer and activator of transcription (STAT) and Shc/Ras/mitogen-activated protein kinase (MAPK) pathways. The precise nature of these signalling routes has not been clarified in detail up until now. We investigated the effect of TPO on activation of cAMP-dependent protein kinase (PKA) and its involvement in MAPK signalling in human megakaryoblastic leukaemia CMK cells. For estimation of PKA activity, phosphorylation of a PKA-specific peptide substrate was assayed in CMK cell lysates. Since activation of PKA is associated with translocation of its catalytic subunit alpha (C-PKA) into the cell nucleus, Western blot analysis of nuclear fractions with an anti-C-PKA antibody was additionally performed. The activation of TPO-induced MAPK activation and the effect of the PKA inhibitor H-89 was measured using immunoblotting with a monoclonal anti-pERK antibody. TPO enhanced cAMP and induced activation of PKA in CMK cells. In addition, H-89 partly blocked TPO-induced MAPK activation in CMK cells. Our results indicate a novel TPO-triggered signalling event, activation of the cAMP/PKA pathway in human megakaryoblastic CMK cells. This signal transduction route seems to be involved in TPO-induced MAPK signaling.

A novel PAR-1-type thrombin receptor signaling pathway: cyclic AMP-independent activation of PKA in SNB-19 glioblastoma cells

Cellular effects of thrombin are mediated by members of a new subfamily of G protein-coupled receptors designated proteinase-activated receptors (PARs) with the prototype PAR-1. Investigation of PAR-1-induced signaling has been shown to be very important in clarifying thrombin's role in cell metabolism, differentiation, and growth. We evaluated connection of PAR-1 with the cAMP/PKA pathway in SNB-19 glioblastoma cells. Alpha-thrombin and the synthetic PAR-1 agonist SFLLRN stimulated PKA as shown by increased PKA activity and translocation of the catalytic PKA alpha subunits (PKA(cat)alpha) into the nucleus. However, no effect on cAMP could be observed. PKA(cat)alpha was found to be associated with nuclear factor-kappa B (NF-kappaB) p65 and its inhibitor protein IkappaB in SNB-19 cells. After PAR-1 stimulation, this association was markedly diminished. We conclude that PAR-1 mediates PKA activation without altering cAMP levels but includes NF-kappaB-associated PKA(cat)alpha in SNB-19 glioblastoma cells. This is the first evidence for a cAMP-independent PKA signaling by a G protein-coupled receptor.

Antidepressant-like properties of zinc in rodent forced swim test

The effects of zinc, the N-methyl-D-aspartate glutamate receptor inhibitor, were studied in mice and rats using the forced swim test. Zinc (ZnSO4) in a dose of 30 mg/kg and imipramine (30 mg/kg), reduced the immobility time in the forced swim test in both species. Moreover, combined treatment in this test with zinc and imipramine at their ineffective doses (1 and 5 mg/kg, respectively) induced a statistically significant effect in rats. The doses active in the forced swim test reduced (in mice) or did not affect (in rats) locomotor activity. The results obtained indicate that zinc induces an antidepressant-like effect and enhances the effect of imipramine in the forced swim test, suggesting a potential antidepressant activity of zinc in humans.

Analysis of the toxic effects of linoleic acid, 12,13-cis-epoxyoctadecenoic acid, and 12,13-dihydroxyoctadecenoic acid in rabbit renal cortical mitochondria

P450 epoxidation of linoleic acid has been associated with many pathological conditions that often lead to acute renal failure. However, there is only suggestive evidence that linoleic acid monoepoxides and/or linoleic diols directly induce mitochondrial dysfunction. Using isolated rabbit renal cortical mitochondria (RCM), we found that linoleic acid (50 microM) and the linoleic acid monoepoxide, cis-12,13-epoxy-9-octadecenoic acid (12,13-EOA, 50 microM) increased state 4 and oligomycin-insensitive respiration and reduced state 3 and oligomycin-sensitive respiration. Concomitant with these effects, linoleic acid and 12,13-EOA decreased mitochondrial membrane potential (DeltaPsi). In contrast, the hydrolyzed product of 12,13-EOA, 12,13-dihydroxyoctadecenoic acid (12,13-DHOA, 50 microM), had no effect on state 3, state 4, oligomycin-sensitive, and oligomycin-insensitive respiration, and DeltaPsi. Neither linoleic acid or its metabolites altered uncoupled respiration, which suggests that these compounds have no affect on electron transport chain in RCM. Nucleotides such as ATP (0.5 mM) and GDP (0.5 mM) partially prevented the decrease in DeltaPsi but did not attenuate the increase in oligomycin-insensitive respiration after exposure to linoleic acid (50 microM) and 12,13-EOA (50 microM). These results demonstrate that linoleic acid metabolism to the 12,13-DHOA is a detoxification pathway that prevents mitochondrial dysfunction in RCM. The increase in state 4 respiration concomitant with decreases in state 3 respiration and DeltaPsi suggest that, in addition to uncoupling effects, linoleic acid and 12,13-EOA may have other effects, such as alterations of mitochondrial membranes. The inability of ATP and GDP to fully attenuate the uncoupling effects of linoleic acid and 12,13-EOA suggests that these effects are mediated through a nucleotide-independent mechanism.

Evidence for functionally active protease-activated receptor-4 (PAR-4) in human vascular smooth muscle cells

1. This study investigates, whether in addition to the protease-activated receptor-1 (PAR-1), PAR-4 is present in vascular smooth muscle cells (SMC) of the human saphenous vein and whether this receptor is functionally active. PAR-1 and PAR-4 are stimulated by thrombin and by the synthetic peptides SFLLRN and GYPGQV, respectively. 2. mRNAs for both, PAR-1 and PAR-4, were detected in the SMC by using reverse transcriptase polymerase chain reaction (RT - PCR). 3. Treatment of the SMC with GYPGQV (200 microM) resulted in a transient increase in free intracellular calcium. This calcium signal was completely abolished after a preceding challenge with thrombin (10 nM), indicating homologous receptor desensitization. 4. Stimulation of the SMC with 10 nM thrombin or 200 microM SFLLRN caused a time-dependent activation of the extracellular signal-regulated kinases-1/2 (ERK-1/2) with a maximum at 5 min. In contrast, 100 nM thrombin as well as 200 microM of GYPGQV induced a prolonged phosphorylation of ERK-1/2 with a maximum at 60 min. These data suggest that PAR-1 and PAR-4 are activated by thrombin at distinct concentrations and with distinct kinetics. 5. GYPGQV stimulated [(3)H]-thymidine incorporation in SMC. At 500 microM, the peptide increased DNA synthesis 2.5 fold above controls. A comparable mitogenic effect was obtained after stimulation of the SMC by 10 nM thrombin or 100 microM SFLLRN, respectively. 6. These data indicate that a functionally active PAR-4 is present in SMC and, in addition to PAR-1, might contribute to thrombin-induced mitogenesis.

Implementation of similarity model in the CSB system for chemical reaction predictions

A new algorithm for predicting the course of chemical reactions, implemented in the CSB system is presented. It allows to use of four various models for reaction generation, that lead to create different solution space according to the needs of the user. Depending on the chosen model one can expect solutions featuring great completeness or great reliability.

[Zinc homeostasis and glutamatergic system in the pathogenesis and treatment of depression]

This article presents a review of the interactions between zinc and glutamate system in the pathophysiology and treatment of depression.

The role of glutamate receptors in antipsychotic drug action

It has recently been postulated that disturbances in glutamatergic neurotransmission may contribute to the pathophysiology of schizophrenia. Therefore the aim of the present study was to evaluate the role of glutamate NMDA and group II metabotropic receptors in the antipsychotic drug action. To this aim the influence of some well-known neuroleptics on cortical NMDA receptors was examined. Furthermore, their behavioral effects were compared with those of the novel agonist of group II glutamate metabotropic receptors, LY 354740, in some animal models of schizophrenic deficits. We found that long-term administration of the typical neuroleptic haloperidol and the atypical one clozapine increased the number of NMDA receptors labelled with [3H]CGP 39653 in different cortical areas. Long-, but not short-term, treatment with haloperidol and raclopride diminished the deficit of prepulse inhibition produced by phencyclidine, which is a model of sensorimotor gating deficit in schizophrenia. In contrast, neither short- nor long-term treatment with clozapine influenced the phencyclidine effect in that model. Acute treatment with LY 354740 reversed neither (1) the deficit of prepulse inhibition produced by phencyclidine or apomorphine, nor (2) the impairment in a delayed alternation task induced by MK-801, which is commonly used to model the frontal lobe deficits associated with schizophrenia. The present study suggests that an increase in the density of cortical NMDA receptors may be important to a longterm neuroleptic therapy. Conversely, the results do not support the role of group II metabotropic glutamate receptors in the antipsychotic drug action.

Does interaction between zinc and glutamate system play a significant role in the mechanism of antidepressant action?

In the central nervous system, zinc modulates predominantly the excitatory amino acid (glutamatergic) neurotransmission. Recent studies demonstrated that chronic antidepressant treatment, which is required for clinical improvement, reduced the reactivity/function of the glutamate/NMDA receptor complex and altered zinc concentration/interaction with this receptor type in the rodent brain. In the cerebral cortex: chronic antidepressant treatment "down-regulated" (reduced density/affinity) of the cortical (but not hippocampal) NMDA receptors measured by radioligand-receptor binding methods. Moreover, chronic imipramine treatment increased the ability of zinc ion to inhibit the NMDA receptor complex in the cerebral cortex but not in the hippocampus. In the hippocampus: chronic treatment with antidepressant drugs (imipramine or citalopram) increased the hippocampus/brain region ratio of zinc concentration, which may indicate redistribution of the rat brain zinc. On the other hand, electroconvulsive shocks induced robust increase of zinc concentration in the hippocampus (with a slight effect in the rest of brain). In spite of the lack of alterations in the hippocampal NMDA receptors (measured by receptor binding methods), inhibitory effect of the increased hippocampal zinc concentration induced by chronic antidepressant treatment, may be responsible for reduction in the function of that receptor complex also in the hippocampus. These data indicate a critical and complex role of the interaction between zinc and NMDA receptor complex in the mechanism of antidepressant treatment and strongly support the glutamate hypothesis of the mechanism of antidepressant action.

Effect of translocation of cirrhotic liver on hepatic venous hemoglobin oxygen saturation during hepatectomy

BACKGROUND/AIMS

Comparison of conventional abdominal approach and right thoracoabdominal approach for the resection of hepatocellular carcinoma in cirrhotic liver located at right upper lobe was made in accordance with the effect of translocation of right lobe on hepatic venous hemoglobin oxygen saturation.

METHODOLOGY

From 1990-1994, 92 initial hepatectomies were performed in patients with hepatocellular carcinoma at our department. Nine patients underwent resections of hepatocellular carcinoma located at the right upper lobe with the right thoracoabdominal approach. On the other hand, 10 patients underwent resections of hepatocellular carcinoma at the same location but with the abdominal approach. We evaluated the effect of translocation of liver by monitoring the hepatic venous hemoglobin oxygen saturation.

RESULTS

The outcome was favorable for the right thoracoabdominal approach for those patients with liver cirrhosis considering less reduction in frequency and degree of hepatic venous hemoglobin oxygen saturation during operation.

CONCLUSIONS

The right thoracoabdominal approach may cause less damage to the liver with severe cirrhosis and preferable to this type of operation compare to the abdominal approach.

Pharmacodynamics and pharmacokinetics of polyethylene glycol-hirudin in patients with chronic renal failure

BACKGROUND

Hirudin selectively inhibits thrombin without cofactors and is eliminated via the kidneys. Recombinant hirudin (r-hi) has a terminal elimination half-life (t1/2) of about 50 to 100 minutes. Coupling of polyethylene glycol (PEG) to r-hi, giving PEG-hirudin (PEG-Hi), prolongs its t1/2 while enhancing efficacy. We looked at the pharmacodynamic and pharmacokinetic behavior of PEG-Hi in patients with impaired renal function.

METHODS

Anticoagulant activity and the pharmacokinetic parameters of a single intravenous bolus injection of 0.05 mg/kg body weight PEG-Hi were studied in 38 subjects. They were assigned to five groups: group IA, creatinine clearance (CCr) >/= 80 mL/min, 8 healthy volunteers; group IB, CCr >/= 80 mL/min, 8 patients with normal renal function); group II, CCr 79 to 50 mL/min, 7 patients with mild chronic renal failure (CRF); group III, CCr 49 to 20 mL/min, 10 patients with moderate CRF; and group IV, CCr </= 19 mL/min, 5 patients with severe CRF. Plasma and urine samples were collected from patients for up to 120 hours after dosing and from healthy volunteers for up to 24 hours.

RESULTS

PEG-Hi was well tolerated in all groups. No serious adverse events were noted. Cmax values were similar in all groups; area under the curve (AUC) increased in patients from 2.9 +/- 1.0 microg. h/mL (IB) to 21.3 +/- 5.0 microg h/mL (IV). According to the severity of renal function, t1/2 was prolonged from 2 hours (IB) to 38.4 hours (IV), while total body clearance (CTB), renal clearance (CRenal), and recovery of PEG-Hi in the urine (FEo-t) decreased as follows: CTB from 23.3 +/- 6.6 (IB) to 2.9 +/- 0.6 mL/min (IV), CRenal from 7.8 +/- 5.0 (IB) to 0.8 +/- 0.5 mL/min (IV), and FEo-t from 40.2 +/- 18. 9% (IB) to 12.6 +/- 13.0% (IV). Total plasma clearance of PEG-Hi was well correlated with CCr. Anti-IIa activity of PEG-Hi showed a closer linear relationship to ecarin clotting time than to activated partial thromboplastin time.

CONCLUSION

Hence, PEG-Hi is considered safe in patients with CRF, but dosing and/or dose intervals should be adjusted according to the severity of renal impairment. Ecarin clotting time is well suited for safe and reliable monitoring of PEG-Hi.

A myosin I isoform in the nucleus

A nuclear isoform of myosin I beta that contains a unique 16-amino acid amino-terminal extension has been identified. An affinity-purified antibody to the 16-amino acid peptide demonstrated nuclear staining. Confocal and electron microscopy revealed that nuclear myosin I beta colocalized with RNA polymerase II in an alpha-amanitin- and actinomycin D-sensitive manner. The antibody coimmunoprecipitated RNA polymerase II and blocked in vitro RNA synthesis. This isoform of myosin I beta appears to be in a complex with RNA polymerase II and may affect transcription.

Stress response in a leporine renal cell model

It is well established that renal proximal tubule (RPT) cells grown under standard in vitro conditions attenuate many of their in vivo properties and functions. Thus, the study of renal stress response mechanisms requires an appropriate cell culture model. In the present study, we compared the heat stress (10 min, 45 degrees C) response of freshly isolated RPT cells with that of RPT cells grown in vitro for 6 days under two different culture conditions: (1) SHAKE conditions, where oxygen levels and physiological functions are maintained via continuous media motion [Nowak G, Schnellmann RG: Am J Physiol 1996;271:C2072-2080] and (2) STILL conditions, involving standard cell culture which leads to partial hypoxia and a marked reduction in physiological functions. The freshly isolated RPT cells progressively synthesized heat shock proteins (HSPs) and stress glycoproteins (SGs) during a 3-hour culture period in vitro. Under these conditions, heat stress did not further increase HSP and SG synthesis. In RPT cells grown under SHAKE conditions, HSP70 synthesis was detected 1 h after heat stress and decreased below detection by 3 h. In contrast, the uptake of radiolabeled mannose into (glycoprotein) GP62 (Mr 62,000), GP50, and GP38 was observed in control SHAKE cultures and was not further increased after heat stress. These results are consistent with immunohistochemistry studies, where similar changes in HSP70 and GP50 expression were noted. RPT cells grown under STILL conditions showed both increased synthesis of HSP70 and increased glycosylation of GP62, GP50, and GP38 as early as 1 h after heat stress, but in contrast to SHAKE conditions, this heat-induced stress response further intensified at 3 h after heat stress. By 7 h after heating, HSP synthesis returned to control levels, while glycosylation of GP62 and GP50 remained elevated. Based on our results, we conclude that freshly isolated RPT cells exhibit a stress response that may be caused by acute cell isolation/culture stress. While this stress response unfolds, freshly isolated RPT cells appear unable to respond to additional heat stress. RPT cells grown under SHAKE and STILL conditions exhibit high rates of SG glycosylation, especially that of GP62, possibly reflecting a 'stress' condition associated with growth on plastic substrate. Concurrently, RPT cells from STILL cultures show a higher capacity for responding to acute heat stress than SHAKE cultures, evidenced by the transiently increased HSP synthetic rates. The interpretation of the renal stress response capacity, therefore, must be linked to a specific culture condition.

Chronic glycine treatment desensitizes the behavioral response to 1-aminocyclopropanecarboxylic acid (ACPC), a partial agonist at the strychnine-insensitive glycine site of the NMDA receptor complex

Chronic treatment with 1-aminocyclopropanecarboxylic acid (ACPC) but not with dizocilpine or imipramine produces desensitization to the behavioral response in ACPC challenge in the forced swim test (forced swim test). The mechanism by which ACPC produces this effect is unclear and may depend upon either its functional antagonist or its agonist properties at the NMDA receptor. We now report that chronic treatment with glycine or ACPC desensitizes the behavioral effect of challenge with ACPC in the forced swim test. The desensitization of the acute effects of ACPC cannot be explained by the presence of residual glycine because 24 h after the last of 14 daily glycine injections (i.e. the time of forced swim test) cortical and hippocampal glycine concentrations were unchanged. Likewise, the affinity of glycine to displace specific [3H]5,7-DCKA binding to glycine sites of the NMDA receptor complex was unchanged by chronic glycine administration. These results support the hypothesis that antidepressants produce adaptation of the NMDA receptor complex by mechanisms other than simply increasing synaptic glycine concentrations. Moreover, these results indicate that the behavioral adaptation in the forced swim test induced by chronic treatment with ACPC results from its agonist properties.

Chronic treatment with antidepressants affects glycine/NMDA receptor function: behavioral evidence

Like the clinically effective benzodiazepine anxiolytic, chlordiazepoxide, the glycine/NMDA receptor antagonist L-701,324 (3, 7.5 and 10 mg/kg), produces dose-related increases in the percentage of time spent in the open arms and the percentage of entries into the open arms of an elevated plus maze in mice. Consistent with its proposed mechanism of action, these anxiolytic effects of L-701,324 (7.5 mg/kg) are reversed by pretreatment with glycine (500 and 800 mg/kg). Chronic treatment with citalopram (20 mg/kg for 21 days), imipramine (15 mg/kg for 21 days) and electroconvulsive shock (ECS, for 8 days), produced a reduction in the anxiolytic-like actions of L-701,324 (7.5 mg/kg) such that they could not be reversed by glycine. In contrast, the anxiolytic effects of L-701,324 and reversal of these effects by glycine were unaffected by acute treatment with imipramine, chronic administration with placebo or the neuroleptic chlorpromazine, or sham ECS. Further, imipramine administered for 21 days did not affect the anxiolytic effect of 5 mg/kg of chlordiazepoxide. The apparent reduction in the anxiolytic-like actions of a specific glycine/NMDA receptor antagonist following chronic treatment with a variety of antidepressants is consistent with previous neurochemical and molecular studies indicating that chronic antidepressant treatment can affect NMDA receptor function.

Zinc exhibits an antidepressant-like effect in the forced swimming test in mice

The effects of zinc, the NMDA receptor inhibitor, were studied in the forced swimming (Porsolt's) test in mice. Zinc (ZnSO4) at a dose of 30 mg/kg (but not at a dose of 10 mg/kg), similarly to imipramine (30 mg/kg), reduced the immobility time in that test. Moreover, zinc at both doses reduced the locomotor activity. The obtained results indicate that zinc induces an antidepressant-like effect in the forced swimming test. Since zinc reduces the locomotor activity, this antidepressant-like effect is not related to the alteration of general activity.

Liver transplantation as rescue treatment in a patient with primary AL kappa amyloidosis

Although involvement of the liver is common in systemic amyloidosis, clinical manifestations of hepatic dysfunction and liver biochemical abnormalities are often absent or only mild. Here we report on a patient with primary amyloidosis and rapid development of liver failure, who was successfully treated by liver transplantation. The patient is a 61-year-old Swedish man who was admitted to the local hospital for spontaneous rupture of the spleen. Before admission, he had suffered from diffuse upper abdominal discomfort, diminished appetite, and had lost 15 kg in 6 months. Shortly after splenectomy, he developed cholestatic liver failure with moderate hepatomegaly, jaundice, ascites and hyponatremia. Over a period of 3 weeks his liver failure progressed, renal function deteriorated rapidly, and he developed encephalopathy. Liver transplantation was performed on the 35th day after splenic rupture. Histological examination revealed extensive deposits of amyloid in the spleen and liver. N-terminal amino acid sequence analysis of the amyloid protein, purified from the patient's native liver, revealed an AL protein of kappa I-type origin. The postoperative course was uncomplicated, apart from one episode of sepsis and one course of treatment for acute rejection. He was discharged from hospital with normal liver function and good kidney function. One year after surgery, he was in good condition, with normal liver function. However, a liver biopsy taken at the same time showed de novo amyloid deposits in the grafted liver. We conclude that liver transplantation may be indicated as a life-saving procedure in rapidly progressing hepatic amyloidosis with cholestatic jaundice, although the underlying disease has not changed.

Ascorbic acid promotes recovery of cellular functions following toxicant-induced injury

We have shown that renal proximal tubular cells (RPTC) recover cellular functions following sublethal injury induced by the oxidant t-butylhydroperoxide but not by the nephrotoxic cysteine conjugate dichlorovinyl-L-cysteine (DCVC). This study investigated whether L-ascorbic acid phosphate (AscP) promotes recovery of RPTC functions following DCVC-induced injury. DCVC exposure (200 microM; 100 min) resulted in 60% RPTC death and loss from the monolayer at 24 h independent of physiological (50 microM) or pharmacological (500 microM) AscP concentrations. Likewise, the DCVC-induced decrease in mitochondrial function (54%), active Na(+) transport (66%), and Na(+)-K(+)-ATPase activity (77%) was independent of the AscP concentration. Analysis of Na(+)-K(+)-ATPase protein expression and distribution in the plasma membrane using immunocytochemistry and confocal laser scanning microscopy revealed the loss of Na(+)-K(+)-ATPase protein from the basolateral membrane of RPTC treated with DCVC. DCVC-injured RPTC cultured in the presence of 50 microM AscP did not proliferate nor recover their physiological functions over time. In contrast, RPTC cultured in the presence of 500 microM AscP proliferated, recovered all examined physiological functions, and the basolateral membrane expression of Na(+)-K(+)-ATPase by day 4 following DCVC injury. These results demonstrate that pharmacological concentrations of AscP do not prevent toxicant-induced cell injury and death but promote complete recovery of mitochondrial function, active Na(+) transport, and proliferation following toxicant-induced injury.

Different signaling pathways are involved in CCK(B) receptor-mediated MAP kinase activation in COS-7 cells

Recently, the involvement of the MAP kinase ERK in mitogenic signaling of cholecystokininB (CCK(B)) receptors has been shown. However, the intracellular effector systems involved in this signaling pathway are poorly defined. In this study, we used COS-7 cells transiently transfected with the human CCK(B) receptor to investigate cholecystokinin-induced MAP kinase activation. CCK-8 induced activation of ERK2 which is associated with its phosphorylation and localization in the nucleus. The CCK-8-dependent ERK stimulation is sensitive to wortmannin an inhibitor of phosphoinositide 3-kinases (PI3Ks) indicating the involvement of PI3K activity. To identify the PI3K species involved in mitogenic signaling of the CCK(B) receptor several dominant-negative mutants of PI3K regulatory and catalytic subunits were transiently expressed. Surprisingly, different catalytically inactive mutants of the G protein-sensitive PI3Kgamma did not affect ERK stimulation induced by CCK, whereas a dominant-negative mutant of the regulatory p85 subunit induced significant inhibition of CCK-dependent ERK activity. These results indicate an involvement of PI3K class 1A species alpha, beta or/and delta in signal transduction via CCK(B) receptors. In addition, protein kinase C (PKC)-dependent signaling pathways contribute to CCK(B)-mediated MAP kinase signaling as shown by inhibition of CCK-8-induced ERK activation by the PKC inhibitor bisindolylmaleimide.