The systemic administration of tacrine or selegiline facilitate spatial learning in aged fisher 344 rats

When compared to young Fisher 344 rats, aged Fisher 344 rats were impaired in their acquisition of the water maze task as indicated by longer escape latencies and distances to find a hidden platform. In a free swim trial which was performed after the training period, young rats had a better spatial bias, since they spent more time swimming in the previous training quadrant. Tacrine 3 mg/kg, an anticholinesterase, and selegiline 0.25 mg/kg, a MAO-B inhibitor, partially reversed the acquisition deficit in aged rats when administered on their own, and drug-treated aged rats swam more in the previous training quadrant than vehicle-treated aged rats during the free swim trial. Aged rats also swam slower than young rats. Tacrine, but not selegiline, increased swimming speed in aged rats. Taken as a whole, these data support the proposal that tacrine may be effective at alleviating age-related learning impairment and confirm the role of cholinergic dysfunction in the spatial learning deficit in aged rats.

Monoamine oxidase B inhibitor selegiline protects young and aged rat peripheral sympathetic neurons against 6-hydroxydopamine-induced neurotoxicity

Selegiline is a selective and irreversible monoamine B inhibitor with the capacity to increase the level of several antioxidative enzymes in rat brain. It can protect adrenergic neurons against injury induced by neurotoxins such as MPTP, DSP-4 and AF64A in animal studies. In addition, the protective action is not limited to catecholaminergic cells, as selegiline can also minimize the loss of developing motoneurons after axotomy. The aim of this study was to determine whether selegiline can protect peripheral catecholaminergic neurons against the neurotoxic effect of 6-OHDA. This kind of protective effect against 6-OHDA neurotoxicity has not been reported before. Wistar albino male rats aged 4 or 24 months were treated with selegiline or saline solution 1 h before 6-OHDA injection. At 2 weeks after the 6-OHDA injection, the superior cervical ganglia (SCG) and submandibular glands (SMG) were studied using catecholamine histofluorescence and immunohistochemistry for tyrosine hydroxylase (TH). The number of TH-positive cells in the SCG and the length and number of adrenergic nerve fibers in the SMG were quantified. Our findings showed that 6-OHDA caused a reduction of TH immunoreactivity and catecholamine histofluorescence in neuronal somata, as well as a decrease in the number and length of adrenergic nerve fibers in the submandibular gland. Selegiline pretreatment protected SCG neurons and their postganglionic nerve fibers in SMG against these changes in a dose-dependent manner. The mechanism through which selegiline exerts its neuroprotective effect is as yet unknown.

Prevention of ethanol-induced sympathetic overactivity and degeneration by dexmedetomidine

The effects of dexmedetomidine, a selective alpha 2-adrenoceptor agonist, on rat sympathetic neurons were studied during a 12-day, heavy ethanol exposure. Adult male Wistar rats were given ethanol or isocaloric sucrose three times a day by intragastric intubation. Both acute (a single dose of 300 micrograms/kg p.o.) and chronic (100 micrograms/kg x 2 P.O. throughout the experiment) effects of dexmedetomidine were tested. The superior cervical ganglia (SCG) of the ethanol-exposed, non-dexmedetomidine-treated rats showed an abnormally high overall level of tyrosine hydroxylase immunoreactivity (TH-IR) and catecholamine histofluorescence. However, a subpopulation of neurons had apparently lost their catecholamine synthetic activity, as they exhibited no TH-IR or catecholamine fluorescence. The ethanol-exposed ganglia also showed structural alterations (e.g., decreased neuronal size and increased occurrence of vacuolated neurons). In the ethanol-exposed, chronically dexmedetomidine-treated group, by contrast, the SCG exhibited TH-IR and catecholamine fluorescence intensities comparable to those seen in the control ganglia. All the structural parameters studied, as well, were at the control level in the chronically dexmedetomidine-treated group. The single dose of dexmedetomidine offered only marginal protection against the ethanol-induced alterations. These results suggest that chronic dexmedetomidine treatment may prevent ethanol-induced overactivity and degeneration of catecholaminergic neurons.

Influence of Hepes- and CO2/HCO(3-)-buffer on Ca2+ transients induced by TRH and elevated K+ in rat pituitary GH4C1 cells

The influence of two buffer systems (Hepes and CO2/HCO3-) on intracellular Ca2+ ([Ca2+]i) transients evoked by TRH and by elevated K+ were studied in single, and small clusters of, clonal rat pituitary GH4C1 cells using Fura 2. The steady-state level of [Ca2+]i was virtually identical in Hepes and CO2/HCO3-. In both buffers, addition of TRH induced a transient increase in [Ca2+]i which attained a significantly higher peak in Hepes (357 +/- 43 nM) when compared with values measured in the presence of CO2/HCO3- (184 +/- 21 nM). In Hepes, the basal IP3-level was higher than in CO2/HCO3-. The TRH-evoked increase in IP3 was higher in magnitude in Hepes than in CO2/HCO3-, although the stimulated/basal ratio was not different between the two buffers. The buffer composition had no effect on the specific binding of 3H-TRH to the cells. Furthermore, the amplitude of the increase in [Ca2+]i evoked by 50 mM K+ was identical in both buffers. TRH and K+ had no effect on pHi in either buffer. The present results indicate that HCO3- has an influence on TRH-induced Ca2+ transient, at least in part by modifying the TRH-evoked production of IP3.

The subrenal capsule assay in selecting chemotherapy for ovarian cancer: a prospective randomized trial

In order to find out whether the response rate and survival in epithelial ovarian cancer can be improved by aid of sensitivity testing with the subrenal capsule assay (SRCA), 196 patients with FIGO Stage II-IV epithelial ovarian cancer were randomized to be treated with either cyclophosphamide-doxorubicin-cisplatin (CAP) or SRCA-guided chemotherapy. The drug combinations tested with the SRCA were (1) cyclophosphamide-doxorubicin-carboplatin (CACAR), (2) CAP, (3) carboquone-methotrexate-tegafur (CQ-MTX-TEG), (4) cisplatin-etoposide-hexamethyl-melamine (P-VP-HXM), and (5) bleomycin-epirubicin-cisplatin (BEP). A total of 132 patients (CAP, 69; SRCA, 63) were eligible for efficacy analysis based on relaparotomy findings. The overall response rate was 59% in the CAP arm and 62% in the SRCA arm. In the SRCA arm, 16 patients were treated with CACAR, 24 with CAP, 10 with CQ-MTX-TEG, 11 with P-VP-HXM, and 2 with BEP. The response rate to CACAR was 63% and to SRCA-CAP was 75%. The number of complete responses was higher when CAP was given as guided by the assay than when given at random (14/24 vs 23/69; P = 0.03, Pearson chi 2). Survival curves as estimated by Kaplan-Meier method gave a median survival of 24 (SE = 4) months to the SRCA arm and 28 (SE = 5) for the CAP arm (P = 0.7; log-rank test). Because no survival benefit was achieved, the SRCA obviously needs further development before it can be routinely recommended in the choice of first-line chemotherapy for patients with ovarian cancer.

The interaction of L-deprenyl and scopolamine on spatial learning/memory in rats

L-Deprenyl, a specific MAO-B inhibitor, has been reported to improve learning/memory in some cognitive tests in aged rats. The present study investigated whether L-deprenyl could alleviate the spatial learning deficit induced by muscarinic blockade and aging in OFA rats. Scopolamine (0.25 mg/kg) impaired the acquisition of a water maze task in adult rats and increased their swimming speeds. L-Deprenyl (0.25 mg/kg, 14 days) had no effect on water maze performance in saline treated adult rats, but markedly alleviated the learning deficit induced by scopolamine and increased the time and distance of swimming in the training quadrant when the platform was removed (spatial probe trial). L-Deprenyl partly reduced the effect of scopolamine on speed of swimming. Nevertheless, administration of l-deprenyl (0.25 mg/kg, 14 days) had no effect on spatial learning/memory in aged rats. We suggest that the l-deprenyl-scopolamine interaction in the water maze test may be considered as a premise for further investigations of l-deprenyl as cognition enhancer.

Electrophysiological and neuropsychological effects of a central alpha 2-antagonist atipamezole in healthy volunteers

We studied the electrophysiological and neuropsychological effects of acute modulation of central noradrenergic (NA) transmission using a specific alpha 2-antagonist atipamezole (ATI) in sic healthy volunteers. ATI had effects on resting EEG, auditory event-related potentials and neuropsychological tests. Quantitative EEG revealed increased total power in frontal, parietal and temporo-occipital areas without significant changes in the mean or peak frequencies. Event-related potentials showed no effects on the active attention-related processing negativity or the passive mismatch negativity, but frontally recorded mean amplitude of target-P300 was decreased. Neuropsychological tests after ATI revealed improvement in Digit Span, more errors in Word Recognition task, and no effects on Moss spatial recognition task. In healthy subjects with intact NA systems and without any attention deficit, ATI produced evident NA overactivity. ATI decreased the spontaneous thalamocortical oscillation of EEG and improved focused attention (Digit Span). It impaired, however, more divided attention (decreased mean P300 amplitude, increased errors in Word Recognition).

The combination of radiotherapy, adjuvant chemotherapy (cyclophosphamide-doxorubicin-ftorafur) and tamoxifen in stage II breast cancer. Long-term follow-up results of a randomised trial

Two hundred patients with node positive stage II breast cancer were randomised to four groups after radical mastectomy and axillary evacuation: (1) Postoperative radiotherapy, (2) Adjuvant chemotherapy with eight courses of CAFt (cyclophosphamide 500 mg m-2 + doxorubicin 40 mg/m-2 + ftorafur 20 mg kg-1 orally day 1-14) every fourth week, (3) Postoperative radiotherapy and adjuvant chemotherapy and (4) postoperative radiation, adjuvant chemotherapy and tamoxifen 40 mg daily for 2 years. Thirty-two per cent of the patients discontinued treatment due to GI-toxicity, while 26% required dose reductions due to leukopenia. Radiation pneumonitis was more frequent after the combination of postoperative radiotherapy with chemotherapy. There was a better relapse-free survival in the groups receiving chemotherapy compared to radiotherapy alone (P = 0.05), which was highly significant in a multivariate Cox analysis (P = 0.004). No significant survival differences were seen. Tamoxifen had no clear overall effect but there were better relapse-free (P = 0.04) and overall (P = 0.004) survival with tamoxifen in estrogen receptor positive patients, while estrogen receptor negative patients had a somewhat poorer survival (P = 0.07) after tamoxifen. Local control was better (NS) after the combination (93%) radiotherapy and chemotherapy compared to either treatment alone (76% with radiotherapy and 74% with chemotherapy at 5 years).

Fall in intracellular pH mediated by GABAA receptors in cultured rat astrocytes

The influence of muscimol (a specific gamma-aminobutyric acid-A (GABAA) receptor agonist) on intracellular pH (pHi) was studied in cultured rat astrocytes by means of fluorescence spectrophotometry with BCECF as the H+ indicator. In an HCO3(-)-free medium, muscimol had little effect on pHi. In a solution containing 22 mM HCO3-, muscimol produced a reversible, concentration-dependent fall in pHi with a maximum of about 0.1-0.15 units. The muscimol-induced fall in pHi was antagonized by an increase in the external K+ concentration, which suggest that the acidosis is an immediate consequence of a net efflux of HCO3- through GABAA receptor channels rather than an indirect effect caused by a change in membrane potential. The present results raise the possibility that astrocytes may participate in the regulation of extracellular pH at GABAergic synapses and contribute to activity-induced pH changes in nervous tissue.

Oral carmofur in advanced gastrointestinal cancer

One hundred and twenty-four patients with a diagnosis of metastatic gastrointestinal cancer and no prior therapy were included in this clinical study of carmofur monotherapy, 300-500 mg/m2 daily for 6 weeks. For the 115 evaluable patients, the response rates were 19.4% in gastric cancer, 27.2% in cancer of mobile colon, and 12.5% in rectal cancer. No objective responses were seen in 38 patients with pancreatic cancer, although the disease of 13 of these patients has remained stable over a considerably long period of follow-up. The toxicity profile was interesting; the main adverse effects were urinary bladder symptoms and flush. Hematologic toxicity was minimal. The treatment proved to be safe and could be used for outpatients.

Multiple-dose pharmacokinetic study with a slow-release carbamazepine preparation

The pharmacokinetics, clinical efficacy and side effects of carbamazepine (CBZ) in the steady-state condition were studied using a slow-release preparation (SR), Neurotol Slow, and a conventional preparation (C), Tegretol. Eighteen adult epileptic patients under CBZ therapy were evaluated in this single-blind, randomized cross-over study. The previous daily CBZ dose was kept unchanged and divided into 2 daily doses during two 2 week study periods. At the end of each period blood samples were drawn at frequent intervals for 12 h after the administration of the morning CBZ dose. Serum concentrations of unchanged CBZ and its main metabolite, carbamazepine-10,11-epoxide (CBZE), were determined by HPLC. Peak concentrations of CBZ and CBZE were significantly lower, and the time-lapse before CBZ reached its peak was significantly longer during SR treatment. The fluctuations in serum CBZ and CBZE were significantly lower during SR treatment. There was no significant difference in bioavailability between the 2 preparations. The number of epileptic seizures was 31 during SR and 57 during C treatment. Side effects were more common during C treatment. The occurrence of dizziness was significantly lower with SR treatment than with C treatment. We conclude that greater stability in serum CBZ and CBZE concentrations can be obtained by using an SR of CBZ, without reducing the bioavailability of the drug.

Differences in side effects between a conventional carbamazepine preparation and a slow-release preparation of carbamazepine

The aim of this double-blind cross-over study was to investigate whether side effects of carbamazepine (CBZ) could be reduced by using a slow-release CBZ preparation. Twenty-one adult patients with epilepsy who had side effects related to the use of CBZ took part in the trial. Patients were randomized to receive either a conventional (C) or slow-release (SR) CBZ preparation for 3 months and were then switched over to the other preparation for another 3 months. The daily dose and dosing frequency of CBZ were kept the same as before the study. The quality and severity of side effects were assessed monthly using a scored questionnaire containing questions about systemic toxicity (STRS) and neurotoxicity (NTRS). Twenty patients could be evaluated. The mean total values of NTRS of 3 monthly visits on each drug were significantly less during SR than during C treatment (P less than 0.05). All the items of NTRS scored lower during SR therapy, and the difference was significant for the occurrence of headache, dizziness and disturbances of vision, speech and coordination. The total score of STRS was also lower during SR, but the difference was not significant. Eleven patients preferred SR, 3 preferred C and 6 patients estimated the periods to be equal. In conclusion, a slow-release preparation of CBZ can render fewer side effects than conventional CBZ preparations.

Vibration stress and the autonomic nervous system

Raynaud's phenomenon has been considered to be due to activation of the central sympathetic vasoconstrictor reflex, and may represent part of a larger dysfunction of higher autonomic centers. Symptoms, such as sweating disturbances, orthostatic hypotension, insomnia and impotence have been reported to be more common among vibration exposed workers. We studied 217 male forest workers and selected samples of this population for electromyographic (N = 80), autonomic nervous system function, controlled breathing, tilting bed and valsalva manoeuvre (N = 88) tests, and a full clinical neurological examination. Mean alcohol consumption was estimated to be 3.0 kg absolute alcohol/year. The total mean vibration exposure time was 14,100 hours. The prevalence of Raynaud's phenomenon was 5%. The variations in heart rate (HRV) at rest and during deep breathing were observed. The traditional indexes of HRV (CV, CVS, MEAN) were computerized and calculated. There was a significant difference (p less than 0.001) between the HRV indexes during the deep breathing test in those with the shortest and the longest exposure to vibration. The values of HRV indexes were age dependent; and in multiple regression analysis, the total exposure time to vibration had an independent negative association to HRV. Also association of sensory neural hearing loss to Raynaud's phenomenon among vibration exposed workers indicates that there is an involvement of the central nervous system in the pathogenesis of vibration syndrome. The question, does vibration cause permanent changes in autonomic centers of the brain or do these centers only mediate vibration stress to end organs, remains unsettled.

Low affinity binding to glutamate receptor sites correlates with depolarizing responses induced by glutamate and quisqualate in striatal synaptoneurosomes

In the present study, binding affinity of glutamate and quisqualate to striatal synaptoneurosome membranes in the guinea-pig was compared with concentration-dependence of depolarizing responses induced by these agents. The displacement of radioactive glutamate from receptor binding site by unlabelled glutamate and quisqualate revealed a nonhomogeneous population of binding sites. A high affinity component of binding was observed with an inhibition constant of 0.04 microM for glutamate and 0.45 microM for quisqualate, as well as a low affinity component with an inhibition constant of 10 microM for glutamate and 87 microM for quisqualate. Changes of the membrane potential in striatal synaptoneurosomes induced by glutamate and quisqualate were detected by measuring the absorbance of a potential sensitive cyanine dye. Glutamate and quisqualate induced constantly a depolarization in synaptoneurosome particles. Concentration-response curves showed that half-maximal depolarization was obtained with 10 microM glutamate and 100 microM quisqualate. The comparison of the displacement data with the changes in the membrane potential in the present investigation indicate that in vitro glutamate and quisqualate depolarize striatal synaptoneurosome particles through low affinity binding to receptor site for glutamate.

Carboplatin and etoposide in advanced lung cancer:--a phase I study

This phase I study was carried out to determine the maximal tolerated dose of carboplatin (Car) together with a fixed dose of etoposide (E) and to recommend the optimal dose for a phase II study. The dose of E was 100 mg/m2 given i.v. on days 1-3, and the starting dose of Car was 200 mg/m2 given i.v. on day 1. The dose was escalated until WHO grade 4 toxicity developed after two treatment cycles in more than one-third of the patients. A total of 33 patients with advanced lung cancer entered the trial. The maximal tolerated toxicity of the combination was reached at a dose of 500 mg/m2 Car. Myelosuppression was moderate, and hematological toxicity of WHO grade 4 was encountered in one of five patients at 475 mg/m2 and in two out of five patients at 500 mg/m2. The main toxic effects were leucopenia and thrombocytopenia. The frequency of treatment-related infections was low and no deaths were caused by treatment. There was a significant overall correlation between the platelet nadir and creatinine clearance. One complete response and three partial responses were achieved after two treatment cycles. Based on the results of the present study, the dose of carboplatin (combined with 100 mg/m2 eposide given on days 1-3) recommended for phase II studies is 450 mg/m2.

Selegiline and levodopa in early or moderately advanced Parkinson's disease: a double-blind controlled short- and long-term study

Selegiline 10 mg per day was compared to placebo as an adjunct to levodopa treatment in this double-blind study of early or moderately advanced Parkinson's disease. Thirty-eight patients completed an initial cross-over trial comprising two treatment periods, each of eight weeks, with a four weeks' wash-out period between them. Thirty of the patients continued in a long-term, double-blind parallel trial with a mean duration of 16 months (range 6-30 months). Selegiline treatment allowed a significant reduction of the necessary daily levodopa dose in both parts of the study and of the daily dosing frequency in the long-term investigation. In spite of this reduction of levodopa dose, an improvement was noted in tremor during the short-term selegiline periods. The side-effects were slight and related to dopamine effects and disappeared after reduction of levodopa-dose. The results support the use of selegiline as an early adjunctive treatment in Parkinson's disease.

Changes of the membrane potential in striatal synaptoneurosome, synaptosome and membrane sac preparations induced by glutamate, kainate and aspartate as measured with a cyanine dye DiS-C2-(5)

The effects of glutamate, kainate and aspartate on the membrane potential of striatal synaptoneurosome, synaptosome and membrane sac preparations were studied by using a potential sensitive cyanine dye DiS-C2-(5). Excitatory amino acids glutamate and aspartate had a depolarizing effect on synaptoneurosomes. 7.9 microM glutamate and 2.8 microM aspartate produced a half-maximal response. Depolarizations induced by glutamate and aspartate were dependent on the concentration of extracellular sodium ions, a maximal response occurred at around 40 mM of external Na+. Kainate induced a dual effect on synaptoneurosomes. In a standard Na+-based medium a hyperpolarization, likely due to inhibition of a presynaptic sodium-dependent glutamate uptake, predominated over a postsynaptic kainate receptor-mediated depolarization that was observed when electrogenic glutamate uptake was inhibited. This interpretation was supported by results obtained with synaptosome and membrane sac preparations. In a standard Na+-based medium kainate had a hyperpolarizing effect on synaptosomes while in the membrane sac preparation kainate induced a depolarization.

Vincristine treatment of acute lymphoblastic leukemia induces transient autonomic cardioneuropathy

Reduced respiratory sinus arrhythmia, measured as heart rate variability, is a reliable indicator of autonomic nervous dysfunction, reflecting a damage in vagal cardiac control. The authors studied the heart rate variability (HRV) of nine children treated for acute lymphoblastic leukemia during the different phases of cytostatic treatment utilizing heart rate processing techniques with a computer. The indices of HRV as well as the spectral components of heart rate were examined with special relation to vincristine administration. The heart rate variability was significantly reduced during the vincristine induction phases as compared to the consolidation and maintenance phases without vincristine administration. In particular, the respiratory components of the HRV during deep breathing tests were significantly reduced during vincristine treatment. The authors conclude that the measurement of the HRV is a suitable method for monitoring transient autonomic neuropathy, which these results show to be a frequent complication of vincristine treatment.

Phase II evaluation of peroral carmofur, cyclophosphamide, and hexamethylmelamine as a second-line therapy in advanced epithelial ovarian carcinoma

A prospective phase II study was performed to evaluate the effect and tolerability of a peroral combination chemotherapy consisting of hexamethylmelamine, cyclophosphamide, and carmofur in patients with epithelial ovarian cancer previously heavily treated by cisplatin-based chemotherapy but no longer responding to it. Of the 27 patients 1 showed a clinical complete remission lasting 15+ months and 4 a partial remission of 6+ to 21 months. A further 7 patients had an unchanged situation of 4 to 13+ months. The median survival of the nonresponders was 3 months. The side effects were tolerable, mostly nausea and vomiting. Only 4 of 27 patients suffered from severe vomiting causing discontinuation of the therapy. The peroral ambulatory chemotherapy prolonged markedly the overall survival of about one-half of the patients with ovarian cancer who previously failed to respond to cisplatin-based chemotherapy.

Reduction of dosing frequency of carbamazepine with a slow-release preparation

The occurrence of side effects and epileptic seizures and the pharmacokinetics of carbamazepine (CBZ) and carbamazepine-10,11-epoxide were studied using a slow-release CBZ preparation, Neurotol slow, and a conventional CBZ preparation, Tegretol. The study was an open, randomized cross-over trial, with a 2 week study period for each preparation. Tegretol was given 3 times and Neurotol slow twice a day. The earlier CBZ dose was kept unchanged. The initial sample consisted of 24 adult epileptic patients receiving CBZ treatment of whom 20 patients were evaluable. The fluctuation in serum CBZ concentrations did not differ significantly between the 2 treatment periods, even though the interdose interval of Neurotol slow was 4 h longer than that of Tegretol. The switch-over from conventional CBZ to the slow-release formulation did not seem to alter the efficacy and side effects of CBZ. By using Neurotol slow instead of a conventional CBZ preparation, Tegretol, it is evidently possible to reduce the dosing frequency from 3 times a day to twice daily administrations.