Levels, uptake, and release of glycine and glutamate in the rat pontine reticular formation.

In this work we have determined the levels of glycine, glutamate, and other amino acids in the rat pontine reticular formation (PRF), in addition to some properties of the uptake and release of labeled glycine and glutamate in slices of this region. Glutamate was the most concentrated amino acid in the PRF, although its content was about half that of the striatum. Surprisingly, glycine levels in the PRF were 3.2-fold higher than in the striatum, whereas GABA content was similar in both regions. The uptake of both glycine and glutamate by PRF slices was strictly Na(+)-dependent. Their release was stimulated by K(+)-depolarization, but only the release of glycine was Ca(2+)-dependent. These findings suggest that glycine is a strong candidate for a neurotransmitter role in the PRF and that glutamate might also play such a role in this region.


Neurochemical changes associated with the action of acute administration of diazepam in reversing the behavioral paradigm conditioned emotional response (CER).

Neurotransmitter turnover of biogenic monoamines (dopamine, norepinephrine, and serotonin) and amino acids (glutamate, aspartate, and gamma-aminobutyric acid) was evaluated in rats exposed to the conditioned emotional response (CER) paradigm in the absence (total suppression) or presence of acute 5 mg/kg i.p. diazepam (which reversed suppression and restored normal responding). Based on previous studies of CER, with controls for shock and stimulus histories, the results with respect to the anxiolytic could be divided into several categories: changes in turnover which are associated only with the CER behavior; changes associated only with the drug, diazepam; changes which augmented the effects of the behavior; or changes which were the reverse of those associated with the behavior. Due to the multitude and complexity of the results, not all observations have clear explanations at this time. However, for the CER behavior per se, it is apparent that a combination of neurotransmitters, including some implications about acetylcholine, act in concert to bring about the behavioral suppression. The action of diazepam is more complex, involving the full spectrum of neurotransmitters to bring about its direct and indirect effects.


The effects of pertussis toxin on dopamine D2 and serotonin 5-HT1A autoreceptor-mediated inhibition of neurotransmitter synthesis: relationship to receptor reserve.

Irreversible inactivation of striatal D2 dopamine (DA) autoreceptors with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) or inactivation of striatal guanine nucleotide binding proteins (G proteins) with pertussis toxin (PT) shifted the dose-response curve for N-n-propylnorapomorphine (NPA)-mediated inhibition of gamma-butyrolactone (GBL)-induced elevation of L-3,4-dihydroxyphenylalanine (L-DOPA) to the right, with a decrease in the maximum response. For the partial agonist (+)-3-(3-hydroxyphenyl)-N-n-propylpiperidine [(+)-3-PPP], in contrast, there was little shift in the ED50, after inactivation of either D2 receptors or G proteins. Completely analogous effects were found at the somatodendritic 5-HT1A autoreceptor in the raphe nuclei, mediating inhibition of the synthesis of serotonin (5-HT); the full agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and the partial agonist, buspirone were utilized to inhibit the synthesis of 5-HT, as measured by changes in levels of L-5-hydroxytryptophan (5-HTP). Additionally, in both systems, combined treatment with pertussis toxin, followed by EEDQ, reduced the maximum effect, when compared to either agent alone but had little further effect on the ED50. In systems exhibiting a large receptor reserve for agonists, such as those described above, the same pattern of response seen after inactivation of receptors or G proteins may reflect the operation of a common mechanism underlying the phenomenon of receptor reserve.


Protection from kainic acid neuropathological syndrome by NMDA receptor antagonists: effect of MK-801 and CGP 39551 on neurotransmitter and glial markers.

Systemic administration of kainic acid results in the development of a characteristic convulsive syndrome, accompanied by neuropathological alterations and loss of transmitter markers in some forebrain regions. Since some of these effects appear to involve the N-methyl-D-aspartate (NMDA) subtype of excitatory amino acid receptors, the protection given by a non-competitive (MK-801) and a competitive (CGP 39551) NMDA receptor antagonist against the loss of glutamatergic and gamma-amino butyric acid (GABAergic) neurochemical markers was compared. Appropriate doses of both compounds (1 mg/kg MK-801 and 25 mg/kg CGP 39551) completely reversed the decrease of high affinity uptake of glutamate and activity of glutamate decarboxylase in the olfactory cortex, amygdala, hippocampus and lateral septum. In addition, they also essentially counteracted the increase of a glial marker, the enzyme glutamine synthetase, consequent to neuronal degeneration. The results confirmed that involvement of NMDA receptors is essential for the full expression of neuropathological effects of kainic acid. They also support the use of a competitive antagonist of the NMDA receptor, such as CGP 39551, to afford substantial protection against the excitotoxic damage, whilst giving fewer side effects and motor disturbances than MK-801.


Injection of the competitive NMDA receptor antagonist AP-5 into the nucleus accumbens of monoamine-depleted mice induces pronounced locomotor stimulation.

Following injection of 5 micrograms of the competitive NMDA receptor antagonist AP-5 into the nucleus accumbens of monoamine-depleted mice a pronounced locomotor stimulation was produced. Additional treatment with an intraperitoneal (i.p.) injection of the alpha-adrenoceptor agonist clonidine markedly increased the locomotor effects of AP-5 administration into the nucleus accumbens. Injection of 5 or 10 micrograms AP-5 into the dorsal striatum was ineffective with regard to locomotor stimulation. However, when AP-5 (10 micrograms) was combined with an i.p. injection of clonidine, a marked locomotor stimulation was produced following application into the dorsal striatum, but not following application into the prefrontal cortex. The present results are in line with the idea that corticostriatal glutamatergic pathways, especially those projecting to the ventral striatum, exert an inhibitory influence on psychomotor functions.


Effects of acute administration of the 5-HT3 receptor antagonist, BRL 46470A, on the behaviour of mice in a two compartment light-dark box and during social interactions in their home cage and an unfamiliar neutral cage.

Adult male CD1 mice received the 5-HT3 receptor antagonist, BRL 46470A, by intraperitoneal injection at three dose levels (2.5 mg/kg, 25 and 2.5 micrograms/kg). Controls were injected with physiological saline. At 30 min after injection, the behaviour of each mouse was examined by ethological procedures, when encountering an untreated partner for 5 min in its home cage and for 5 min in the more aversive situation of an unfamiliar neutral cage. The behaviour of each mouse also was monitored for 5 min in a two compartment light-dark box. At all doses tested, BRL 46470A increased the time spent in the light compartment of the light-dark box. At the smallest dose (2.5 micrograms/kg), the number of transitions between light and dark compartments was increased and there also was an increase (per unit time) in the numbers of squares crossed and number of scans in the light compartment. At all doses tested, BRL 46470A increased social investigation and reduced non-social exploratory activity in both the home cage and the unfamiliar neutral cage. In both test situations, increase of social investigation was maximum at 25 micrograms/kg, and at this dose, aggressive behaviour was also enhanced. In the neutral cage, digging in the sawdust by drug-treated mice showed a progressive dose-related increase. These results indicate potent anxiolytic-like activity by BRL 46470A and also demonstrate increased reactivity to unfamiliar environmental stimuli, such as novel sawdust. The significance of these findings is discussed.


Endogenous opioids may be involved in idazoxan-induced food intake.

In this study it has been shown that the unexpected increase in food consumption, produced by the alpha 2-adrenoceptor antagonist idazoxan (10 mg/kg, i.p.) in rats, was significantly attenuated by small doses of the opioid antagonist (-)-naloxone (0.1, 1 mg/kg, i.p.) and totally inhibited by a small dose of naltrexone (1 mg/kg, i.p.). On the other hand, idazoxan-induced feeding was not affected by (+)-naloxone (0.1, 1 mg/kg, i.p.), which is inactive at opioid receptors. In addition, idazoxan-induced food consumption was not blocked by the delta-opioid antagonist, naltrindole (0.1, 1 mg/kg, i.p.) nor by the mu/delta-antagonist, RX8008M (16-methyl cyprenorphine; 0.1, 1 mg/kg, i.p.), which clearly discriminates between mu/delta- and kappa-opioid receptor function in vivo. These findings suggest that idazoxan may lead to the release of endogenous opioid peptides, which subsequently stimulate feeding by activation of kappa-, as opposed to mu- or delta-opioid receptors. This response is unlikely to be due to alpha 2-adrenoceptor blockade, since other highly selective alpha 2-adrenoceptor antagonists do not increase food intake and, instead may reflect the high affinity of idazoxan for non-adrenoceptor idazoxan binding sites.


[Droperidol in the treatment of hiccup of central origin].

Persistent intractable hiccup (over 24 hours) was observed in four patients. Administration of 2.5 mg droperidol intravenously stopped the hiccup for some hours (4-12). This dose was repeated every 4-12 hours for some days. The hiccup stopped completely.


Evidence for differential opioid mu 1- and mu 2-receptor-mediated regulation of heart rate in the conscious rat.

The possibility that mu-opioid-induced tachycardia and bradycardia could be mediated by different subtypes of the mu-receptor was studied in conscious Sprague-Dawley rats. The selective mu-receptor agonist dermorphin and its analog, TAPS (Tyr-D-Arg-Phe-sarcosine), a putative mu 1-receptor agonist, were given centrally. Tyr-D-Arg-Phe-sarcosine increased the heart rate, the response being inversely correlated to the dose (an increase of 71 +/- 22, 49 +/- 14 and 30 +/- 17 beats/min at doses of 0.3, 3 and 30 pmol, respectively). Dermorphin induced less clear changes in heart rate (maximum increase of 39 +/- 14 beats/min at the dose of 1 pmol). After treatment with the mu 1-selective antagonist naloxonazine (NAZ), TAPS 30 pmol and dermorphin 1 pmol decreased heart rate by -22 +/- 10 and -24 +/- 7 bpm, respectively. The bradycardiac effect of larger doses of dermorphin was potentiated by NAZ (from -25 +/- 8 to -97 +/- 22 bpm) but abolished by the non-selective antagonist naloxone. These data suggest that the high affinity mu 1-opioid receptors mediate tachycardic responses and mu 2-receptors mediate bradycardic responses.


Effects of somatostatin and anti-somatostatin serum on picrotoxin-kindled seizures.

The effects of somatostatin, administered into different areas of the brain were studied in preliminary picrotoxin-kindled rats. The injection of somatostatin into the lateral ventrical of the brain (i.c.v.) (1.8 nmol), the hippocampus (0.6 nmol) or the amygdala (0.6 nmol), resulted in a decrease in the severity of the picrotoxin-induced convulsions. Application of the peptide into the caudate-putamen or the substantia nigra reticulata did not alter the behavioural manifestations of the kindled seizures. The local injection of anti-somatostatin serum (1:5) into the hippocampus increased the severity of the kindled convulsions and blocked the anticonvulsive effect of somatostatin, given intraventricularly. Local administration of anti-somatostatin serum into the amygdala did not alter the kindled seizures and did not abolish the anticonvulsive action of somatostatin given intraventricularly. It is concluded that somatostatin could take part in endogenous control of seizures through a suppressant influence on limbic structures; the hippocampus could be a specific site for the antiepileptic action of somatostatin.


Estradiol plus progesterone promote glutamate-induced release of gamma-aminobutyric acid from preoptic area synaptosomes.

Treatment of ovariectomized rats with both estradiol and progesterone in vivo resulted in a marked enhancement of glutamate-induced release of newly synthesized [3H]gamma-aminobutyric acid (GABA) from synaptosomes of the preoptic area in vitro. With this treatment, as little as 0.01 nM glutamate, in vitro, enhanced release of GABA. In contrast, glutamate, in vitro, did not stimulate release of GABA from synaptosomes, obtained from rats treated with either estradiol or progesterone alone and only large concentrations of glutamate (1.0 and 10 mM) caused a modest release of GABA from synaptosomes from ovariectomized, vehicle-treated rats. Also, treatment with estradiol plus progesterone did not alter glutamate-induced release or exchange of [3H]glutamate. Glutamate-induced release of GABA was calcium-independent and attenuated by the putative chloride channel antagonist, 4,4'-diisothiocyanatostilbene-2,2'-DL-disulfonic acid. Thus, glutamate-induced, steroid-enhanced release of GABA may occur through a chloride-dependent carrier rather than by exocytosis. In addition to enhancement by glutamate, release of GABA was also enhanced by D-aspartate, an agent that is transported by the neuronal glutamate carrier. It is postulated that enhancement of glutamate-induced release of GABA, by estradiol plus progesterone in the preoptic area, represents one process by which these steroids modulate reproductive function in female rats.


Activity of two primary human metabolites of nomifensine on stimulated efflux and uptake of dopamine in the striatum: in vitro voltammetric data in slices of rat brain.

Several antidepressant drugs have active metabolites. This study sought to establish whether two of the main human metabolites of nomifensine (M2: 8-amino-2-methyl-4-(3-methoxy-4-hydroxyphenyl)-1,2,3,4- tetrahydroisoquinoline and M3: 8-amino-2-methyl-4-(3-hydroxy-4-methoxyphenyl)-1,2,3,4- tetrahydroisoquinoline) had actions on the release and uptake of dopamine (DA). Experiments were conducted in superfused striatal slices of the rat. The efflux of DA was evoked by single constant-current pulses (0.1 msec, 10 mA) and trains (20 pulses, 50 Hz), applied alternately every 10 min and monitored using fast cyclic voltammetry at carbon fibre microelectrodes. Nomifensine (5 x 10(-7) M) significantly increased the efflux of DA on both single pulse (302% of pre-drug) and train stimuli (529%) and increased the uptake half-life (178% of pre-drug). The M2 metabolite had similar potency on the efflux of DA (260%: pulse, 570%: train) but without any effect on uptake of DA. Nomifensine and M2 increased efflux of DA more on trains than on single pulses. The M3 metabolite (5 x 10(-7) M) increased efflux of DA only moderately. The selective blocker of the uptake of DA, GBR 12909 (3 x 10(-7) M), increased efflux of DA on single pulse (430%) and train stimuli (645%) and blocked uptake of DA (t1/2: 292%). Amfonelic acid, the psychomotor stimulant (10(-7) M) blocked uptake of DA (t1/2: 234%) and elevated efflux of DA to a greater extent on trains (1007%) than on single pulses (495%).(ABSTRACT TRUNCATED AT 250 WORDS)


Protective effect of epidermal growth factor on glutamate neurotoxicity in cultured cerebellar neurons.

The effects of epidermal growth factor (EGF) on glutamate-induced neuronal death were investigated in primary cultures of dissociated cerebellar neurons from fetal rats. Addition of an excess concentration of L-glutamate (5 mM) to the culture medium greatly decreased the number of surviving neurons 24 h later. When EGF was added to the culture medium 20 h prior to exposure to glutamate, glutamate-induced neuronal death was significantly reduced. The protective effects of EGF on glutamate neurotoxicity were concentration-dependent in the range of 0.01-10 ng/ml. When EGF was added 1 h prior to exposure to glutamate, it did not prevent glutamate-induced neuronal death, indicating that a longer exposure period is required for EGF to exert its protective effects. Furthermore, the protective effects of EGF on glutamate neurotoxicity disappeared in the presence of cycloheximide (0.1 microM), a protein synthesis inhibitor. These results suggest that EGF can protect brain neurons against glutamate toxicity through some protein synthesis.


Correlation of c-erbB-2 protein expression and lymph node status in early gastric cancer.

For the prediction of nodal status of early gastric cancer, sections of formalin-fixed, paraffin-embedded tissue from 220 early gastric cancers were analyzed immunohistochemically, using a polyclonal antibody against erbB-2 protein. The data of erbB-2 protein expression have been correlated with pathologic data, and a logistic regression analysis was made for the estimation of the significant factors responsible for lymph node metastasis. A pattern consistent with cell membrane staining was regarded as most specific for the erbB-2 expression. There were 22 (10%) cancers with evidence of erbB-2 protein expression. Positive staining was associated with only lymph node metastasis. The risk of lymph node metastasis was 3-fold greater in tumors having erbB-2 protein expression than in tumors without the expression. When the erbB-2 tissue status and clinicopathological parameters were entered into the logistic regression analysis, erbB-2 protein expression emerged as one of the independent significant factors for lymph node metastasis. These results indicate that early gastric cancer with erbB-2 protein expression may represent a potential risk of lymph node metastasis.


Immunohistochemical detection of P glycoprotein, glutathione S transferase and DNA topoisomerase II in human tumors.

The expression of the drug resistance markers P glycoprotein (P-170), glutathione S transferase-pi (GST-pi) and DNA topoisomerase II (Topo II) was analyzed in 16 human kidney carcinoma cell lines, 18 hematological malignancies, and 14 human breast carcinomas. We found a tendency for coexpression of increased P-170 and GST-pi and of increased P-170 and decreased Topo II expression in kidney carcinoma cell lines. A similar tendency was found between P-170 and GST-pi expression in breast carcinomas. In contrast, hematological malignancies did not show such a coexpression of resistance markers. Furthermore, we found interrelationships between the expression of resistance markers, resistance to doxorubicin or vincristine, and doubling times of kidney carcinoma cell lines. This indicates that the proliferative activity of tumor cells plays a role for the expression of resistance markers and the development of resistance to cytostatic drugs.


Potentiation of lymphocyte proliferative responses by nickel sulfide.

Crystalline nickel sulfide (NiS) induced a spleen cell proliferation that resembles a mixed lymphocyte reaction (MLR). It depended on cell-cell interaction, induced high levels of interleukin-1 (IL-1) and interleukin-2 (IL-2) and the responding cell subpopulation was composed of CD4+ T lymphocytes. Furthermore, the proliferation was inhibited in a dose-dependent manner by magnesium. Crystalline NiS also increased significantly the spleen cell proliferative response to concanavalin A (Con A) and lipopolysaccharide (LPS) with magnesium potentiating the combined effects of crystalline NiS and mitogens. Interestingly, crystalline NiS did not show any effect on the induction of IL-2 by Con A. The results described herein suggest that crystalline NiS can potentiate both antigenic (MLR) and mitogenic (Con A and LPS) proliferative responses in vitro. Crystalline NiS appears to potentiate these responses by acting in the form of ionic nickel on several intracellular targets for which magnesium ions have different noncompetitive interactions. The effects of magnesium on the potentiating action of crystalline NiS are different depending upon the type of primary stimulatory signal for proliferation (mitogenic or antigenic).


CD45RA and CD45RO positive CD4 cells in human peripheral blood and periodontal disease tissue before and after stimulation with periodontopathic bacteria.

Flow cytometric analysis was used to examine naive and primed or memory CD4 cells extracted from periodontal lesions compared with cells from peripheral blood of healthy subjects before and after stimulation with the periodontopathic bacteria, Porphyromonas gingivalis and Fusobacterium nucleatum. In peripheral blood, approximately 60% and 40% of CD4 cells were CD45RO+ and CD45RA+ respectively at day 0. Phytohaemagglutinin (PHA) induced CD45RO expression on almost 100% of CD4 cells. However, P. gingivalis and F. nucleatum stimulation did not cause any significant change in percentage of CD45RO+ CD4 cells except for a loss of antigen at day 6 together with re-expression at day 7, which also occurred on cells cultured in medium only. CD45RA expression on PHA and bacterial-stimulated peripheral blood CD4 cells remained fairly stable for the 10-d culture period. Greater than 90% CD4 cells extracted from healthy or marginal gingivitis (H/MG) and adult periodontitis (AP) lesions were CD45RO+ and this was maintained on AP cells throughout the 6-d culture period, except for a small decrease in the percentage of positive cells induced by P. gingivalis at day 3. Approximately 9% CD4 cells from H/MG tissue were CD45RA+, but about 22% AP cells expressed this antigen, and this increased again in P. gingivalis- and F. nucleatum-stimulated cultures after 3 d. Therefore, in peripheral blood P. gingivalis and F. nucleatum do not act as nonspecific T-cell mitogens and, in AP cells, these bacteria induce changes in phenotype, supporting previous data that although they may be polyclonal B-cell activators, they activate antigen specific T-cells.


Slow inward current in single cells isolated from adult human ventricles.

Characteristics of the slow inward current (Isi) in human ventricular myocytes isolated from septal specimens obtained in patients undergoing corrective cardiac surgery were studied using the whole-cell clamp method. A first series of experiments was performed under normal standard superfusion. Clamping from -60 mV evoked an inward current with a threshold at about -35 mV, a maximum around +10 mV and an apparent reversal potential at about +55 mV. No overlapping transient or background outward currents were detected in the -60 to +30 mV potential range, but time-dependent and steady-state outward currents were elicited at potentials above +30 mV. An overlap of steady-state activation and inactivation curves was present between -30 and +10 mV and a slight relief from inactivation was observed for voltages positive to +10 mV. The time course of inactivation consisted of fast and slow phases with time constants differing by a factor of eight. Slow time constants of inactivation were shorter at potentials that elicited larger Isi, and longer at potentials inducing smaller Isi. Recovery from inactivation evolved slowly with 100% reactivation occurring in about 4000 ms. Switching the holding potential from -60 to -40 mV led to a reversible decline of Isi without any change of the decay time constants. Isi was significantly increased by 0.1 microM isoproterenol. Total or partial inhibition by inorganic (2 mM Mn2+, 3 mM Co2+, 1 mM Cd2+) and organic (1 microM methoxyverapamil, 5 microM diltiazem) calcium antagonists did not unmask any transient outward current. However, a consistent increase of Isi was reversibly observed with 3 mM 4-aminopyridine while using standard solutions. A second series of experiments carried out with K(+)- and Na(+)-free solutions did not demonstrate any significant change from data observed with standard solutions except a reduction of outward currents at steps above +30 mV and alteration of inactivation kinetics. In this experimental setting, 4-aminopyridine also increased Isi but to a lesser degree. We conclude that Isi, as compared to the outward currents, is dominant in the diseased human ventricular cells we have studied.


Partial purification and reconstitution of the human multidrug-resistance pump: characterization of the drug-stimulatable ATP hydrolysis.

Multidrug-resistant human tumor cells overexpress the MDR1 gene product P-glycoprotein, which is believed to function as an ATP-dependent efflux pump. In this study we demonstrate that the partially purified P-glycoprotein, when reconstituted in an artificial membrane, catalyzes drug-stimulated ATP hydrolysis. Plasma membrane proteins of a human multidrug-resistant cell line, KB-V1, were solubilized with 1.4% (wt/vol) octyl beta-D-glucopyranoside in the presence of 0.4% phospholipid and 20% (vol/vol) glycerol, and the crude detergent extract was chromatographed on DEAE-Sepharose CL-6B. The 0.1 M NaCl fraction, enriched in P-glycoprotein but devoid of Na,K-ATPase, was reconstituted by the detergent-dilution method. P-glycoprotein constituted 25-30% of the reconstituted protein in proteoliposomes. ATP hydrolysis by proteoliposomes was stimulated 3.5-fold by the addition of vinblastine but was unaffected by the hydrophobic antitumor agent camptothecin, which is not transported by P-glycoprotein. The stimulatory effect of vinblastine was observed only if the protein was reconstituted in proteoliposomes, suggesting that either the substrate binding site(s) was masked by detergent or that the conformation of the soluble P-glycoprotein might not be suitable for substrate-induced activation. Several other drugs that are known to be transported by P-glycoprotein enhanced the ATPase activity in a dose-dependent manner with relative potencies as follows: doxorubicin = vinblastine greater than daunomycin greater than actinomycin D greater than verapamil greater than colchicine. The basal and vinblastine-stimulated ATPase activities were inhibited by vanadate (50% inhibition observed at 7-10 microM) but were not affected by agents that inhibit other ATPases and phosphatases. These data indicate that the P-glycoprotein, similar to other ion-transporting ATPases, exhibits a high level of ATP hydrolysis (5-12 mumol per min per mg of protein).


N-methyl-D-aspartate receptors are transiently expressed in the developing spinal cord ventral horn.

Quantitative receptor autoradiography was used to map the distribution of N-methyl-D-aspartate (NMDA) receptors in the developing rat spinal cord. Three different specific ligands, which label partially overlapping subpopulations of NMDA receptors, were used: an agonist (L-[3H]glutamate), a noncompetitive antagonist ([3H]MK-801), and a competitive antagonist ([3H]CGP-39653). In the adult, NMDA receptors labeled with all three ligands are restricted to the substantia gelatinosa in the spinal dorsal horn. In marked distinction, at postnatal day 7 NMDA receptors labeled with L-[3H]glutamate and [3H]MK-801 are present throughout the spinal gray matter. NMDA receptors in the neonatal spinal ventral horn have a higher affinity for L-[3H]glutamate than those in the adult substantia gelatinosa. Over the second and third postnatal weeks, NMDA receptors are lost from all areas of the spinal gray matter except for the substantia gelatinosa. Neonatal NMDA receptors identified with [3H]CGP-39653 are restricted to the substantia gelatinosa. These results show that the immature ventral horn contains a subpopulation of NMDA receptors and raise the possibility that motor neurons transiently express NMDA receptors in early postnatal life. Ventral horn NMDA receptors may be a component of the mechanisms by which the mature phenotype of motor neurons is acquired through activity-dependent processes. The loss of NMDA receptors over the course of development may play a role in limiting the period of motor neuron plasticity.


Chromosome location of Oryza sativa recombination linkage groups.

In situ hybridization, a powerful tool for the molecular cytogeneticist, can be used to physically map repetitive, low-copy, and unique DNA sequences in plant chromosomes. With the availability of a recombination map in Oryza sativa L. and an improved in situ hybridization technique, this study was designed to establish the relationship between the genetic and physical distances of the rice restriction fragment length polymorphism map. Analysis indicated that considerable variation can exist between genetic and physical maps. A 183-centimorgan linkage map for chromosome 2 covered less than 50% of the chromosome and did not include the centromere, whereas a 91-centimorgan linkage map for chromosome 1 covered approximately 80% of the chromosome. The results indicated that there are potential "hot" and "cold" spots of recombination and polymorphisms in rice, which involve both genes and restriction fragment length polymorphisms.


Identification, characterization, and DNA sequence of a functional "double" groES-like chaperonin from chloroplasts of higher plants.

Chloroplasts of higher plants contain a nuclear-encoded protein that is a functional homolog of the Escherichia coli chaperonin 10 (cpn10; also known as groES). In pea (Pisum sativum), chloroplast cpn10 was identified by its ability to (i) assist bacterial chaperonin 60 (cpn60; also known as groEL) in the ATP-dependent refolding of chemically denatured ribulose-1,5-bisphosphate carboxylase and (ii) form a stable complex with bacterial cpn60 in the presence of Mg.ATP. The subunit size of the pea protein is approximately 24 kDa--about twice the size of bacterial cpn10. A cDNA encoding a spinach (Spinacea oleracea) chloroplast cpn10 was isolated, sequenced, and expressed in vitro. The spinach protein is synthesized as a higher molecular mass precursor and has a typical chloroplast transit peptide. Surprisingly, however, attached to the transit peptide is a single protein, comprised of two distinct cpn10 molecules in tandem. Moreover, both halves of this "double" cpn10 are highly conserved at a number of residues that are present in all cpn10s that have been examined. Upon import into chloroplasts the spinach cpn10 precursor is processed to its mature form of approximately 24 kDa. N-terminal amino acid sequence analysis reveals that the mature pea and spinach cpn10 are identical at 13 of 21 residues.


Class-level relationships in the phylum Cnidaria: evidence from mitochondrial genome structure.

The phylogenetic relationships of the Recent cnidarian classes remain one of the classic problems in invertebrate zoology. We survey the structure of the mitochondrial genome in representatives of the four extant cnidarian classes and in the phylum Ctenophora. We find that all anthozoan species tested possess mtDNA in the form of circular molecules, whereas all scyphozoan, cubozoan, and hydrozoan species tested display mtDNA in the form of linear molecules. Because ctenophore and all other known metazoan mtDNA is circular, the shared occurrence of linear mtDNA in three of the four cnidarian classes suggests a basal position for the Anthozoa within the phylum.


Developmentally regulated Drosophila gene family encoding the fork head domain.

We have isolated seven Drosophila genes by means of low-stringency hybridization to a DNA probe containing the coding sequence for the protein domain shared by the rodent hepatocyte-enriched nuclear transcription factor HNF3A (alpha) and the product of the Drosophila region-specific homeotic gene fork head (fkh). The previously unreported genes encode a 110-amino acid conserved sequence, which we call the fork head (fkh) domain. Two of these fkh-domain-encoding genes ("FD genes") map to the sloppy paired locus (slp), which exerts segmentation gene function. The expression patterns of the other FD genes suggest that their protein products are likely to be involved in gut formation, mesoderm specification, and some specific aspects of neural development. The FD gene products presumably represent a family of transcription factors that, like the previously identified DNA-binding proteins, contribute to early developmental decisions in cell fates during embryogenesis.


Adipogenic cell line TA1: a suitable model to study the effect of beta-adrenergic agonists on lipid metabolism.

The stable adipogenic cell line TA1 was investigated as a potential in vitro system to examine effects of beta-adrenergic agonists on lipid metabolism at the cellular level. Initial experiments were conducted to establish whether dexamethasone, indomethacin, or both in combination induce rapid differentiation of TA1 preadipocytes to adipocytes. Based on activity of fatty acid synthase, dexamethasone and indomethacin, individually and in combination, were observed to induce differentiation in TA1 cells at different rates (dexamethasone/indomethacin greater than indomethacin greater than dexamethasone). Dexamethasone/indomethacin induced complete differentiation in TA1 cells 4 days after confluence, as indicated by increased activity of fatty acid synthase, glycerol-3-phosphate dehydrogenase, and malic enzyme. Finally, mature TA1 adipocytes were treated with various concentrations of isoproterenol and ractopamine to determine the responsiveness of TA1 adipocytes to a beta-adrenergic challenge. Glycerol release was increased and fatty acid synthase activity was decreased in a dose-dependent manner for both isoproterenol and ractopamine. These results indicate that fully differentiated TA1 adipocytes may be useful to study direct cellular effects of lipolytic and lipogenic agents on lipid metabolism.


Aminorex produces stimulus effects similar to amphetamine and unlike those of fenfluramine.

A 4-methyl derivative of aminorex has recently appeared on the clandestine market as a designer drug. In the present study, the stimulus effects of aminorex itself were evaluated in rats trained to discriminate either 0.75 mg/kg S(+)-amphetamine or 1.5 mg/kg fenfluramine from saline. The amphetamine stimulus (ED50 = 0.14 mg/kg) generalized to aminorex (ED50 = 0.23 mg/kg), which was found to be slightly less potent than (+)-amphetamine. Fenfluramine stimulus generalization did not occur to aminorex. Thus, the stimulus effects of aminorex are qualitatively similar to those of amphetamine and unlike those of fenfluramine.


NMDA receptor inhibition prevents tolerance to cocaine.

Male rats were treated with cocaine by utilizing two different experimental paradigms. One group of animals received a low dose (10 mg/kg, IP) of cocaine for 7 days. A second group received 40 mg/kg IP of cocaine for 3 days. In both experimental groups, half the animals were concomitantly treated with 0.25 mg/kg IP (+)-5methyl-10,11-dihydro-5H-dibenzo-[a,d]-cyclohepten-5,10- imine maleate (MK-801), a noncompetitive NMDA receptor antagonist. Rats treated with the low dose of cocaine after 7 days developed tolerance to the stimulation of locomotor activity induced by cocaine and by the dopamine D2 agonist quinpirole. Rats treated with 40 mg/kg of cocaine showed a marked behavioral sensitization. Both these effects, tolerance and sensitization, were prevented by coadministration of MK-801, thus suggesting these two phenomena are different aspects of a common neuronal response in which NMDA transmission plays a crucial role.


Increased sexual behavior in male Macaca arctoides monkeys produced by atipamezole, a selective alpha 2-adrenoceptor antagonist.

The effect of a highly selective and potent alpha 2-adrenoceptor antagonist, atipamezole, on sexual behavior was studied in three stumptail macaques (Macaca arctoides). Following IM administration of atipamezole or saline control, the behavior of the male monkey with a female monkey was observed for 30 min. Atipamezole dose dependently (0.01-0.15 or 0.30 mg/kg) produced a significant increase in the number of ejaculations in all three monkeys, including an old one with decreased sexual activity in control conditions. Both ejaculations obtained by copulation and masturbation were increased. It is concluded that atipamezole is effective in increasing sexual behavior in male stumptail monkeys.


Reversal of cirazoline- and phenylpropanolamine-induced anorexia by the alpha 1-receptor antagonist prazosin.

Phenylpropanolamine (PPA) is a phenethylamine anorectic drug that exerts direct agonist effects predominantly on alpha 1-adrenoceptors, with some alpha 2-adrenergic activity. Microinjections of PPA, as well as the alpha 1-adrenergic receptor agonists cirazoline, methoxamine, and 1-phenylephrine, into rat paraventricular nucleus (PVN) suppress feeding. The present study further evaluates the alpha 1-adrenergic basis of PPA-induced anorexia by examining the effects of systemic injections of the alpha 1-adrenergic antagonist prazosin (PRAZ, 2 and 5 mg/kg, IP) on the anorexia induced by systemic injections of PPA (5, 10, and 20 mg/kg, IP), as well as cirazoline (0.05, 0.1, and 0.2 mg/kg, IP). Although neither PRAZ dose alone altered food intake in the present study, 2 mg/kg PRAZ effectively reversed the feeding-suppressive effects of both PPA and cirazoline. These results strongly support the hypothesis that alpha 1-adrenoceptor stimulation mediates the anorexia induced by drugs such as PPA and cirazoline.


Alpidem and lorazepam in the treatment of patients with anxiety disorders: comparison of physiological and psychological effects.

The physiologcal and psychological effects of the novel imidazo-pyridine alpidem were compared with those of the benzodiazepine lorazepam in the context of a clinical trial. Twenty-three psychiatric out-patients with generalised anxiety disorder received alpidem (mean dose 112.5 mg daily) or lorazepam (mean 3.5 mg daily) in doses adjusted to clinical need under double-blind conditions. A battery of tests was performed before and after four weeks treatment. Anxiety scores improved very significantly in both groups with no subjective sedation nor other particular side-effects noted in either group. However, lorazepam reduced the EEG averaged evoked response and produced significant impairment in the reaction time and memory tests whereas alpidem had no such effects. Alpidem therefore shows promise as an effective anxiolytic devoid of the adverse psychomotor and cognitive effects often associated with the benzodiazepines.


Effect of sulfasalazine on adaptive and functional changes in intestine of normal and protein-calorie-malnourished rats.

The effects of sulfasalazine (500 mg/kg body weight daily for 35 days) and its subsequent recovery for another 35 and 65 days have been investigated on the intestinal uptake of certain end-product nutrients, viz. glucose, leucine, alanine, and calcium, in normal and protein-calorie malnourished (PCM) male albino rats. Sulfasalazine administration caused a reduction in body weight in PCM animals, while intestinal weight and length as well as protein and nucleic-acid contents were reduced in both normal and PCM animals. Serum proteins also showed a decrease in PCM rats. PCM rats showed elevated levels of glucose, amino acids, and calcium uptake by the intestinal segments, but sulfasalazine feeding inhibited the uptake of nutrients both in normal-fed and malnourished animals. All these changes were found to be reversible after the withdrawal of drug treatment. Sulfasalazine caused a decrease in the Na(+)-dependent (active) glucose uptake as well as the Na(+)-independent (passive) process. The kinetic parameters of glucose uptake indicate that the drug might interfere with the transport/carrier protein of these nutrients, because reduction was observed in maximum uptake velocity (Jmax) of these systems without any change in the affinity constant (Kt).


HLA-DQA1 and MLC among HLA (generic)-identical unrelated individuals.

We modified a previously published PCR-RFLP for DQA1 typing (1) and examined the predictive value of HLA-DQA1 in mixed lymphocyte cultures (MLC) among matched (HLA generic types) pairs of unrelated individuals. There were 61/102 (60%) pairs with positive MLC, one-third of which could be predicted by DQA1* typing alone. DQA1 matching and MLC reactions were classified into 3 groups: 1) DQA1 mismatches showing positive MLC: 19/102 (19%); 2) DQA1 matches showing negative MLC: 41/102 (40%); 3) DQA1 identical showing positive MLC: 42/102 (41%). Five different HLA haplotypes that result from non-random association of HLA generic types (high delta haplotypes) were overrepresented in the individuals tested. One of these haplotypes carrying HLA-B7, DR2 was found associated with three different DQA1 alleles (*0201, *0103, *0102). The remaining four high delta haplotypes were associated with one DQA1 allele in all independent examples tested: HLA-A1, B8, DR3 with DQA1*0501; HLA-A26, B38, DR4 with DQA1*0301; HLA-A2, Bw62, DR4 with DQA1*0301 and HLA-A1, Bw57, DR7 with DQA1*0201. Forty per cent of the negative MLC were explained in part by the excessive number of individuals carrying two of these four haplotypes, which probably carry determinants in linkage disequilibrium with HLA. Nineteen per cent of HLA-identical (generic types) unrelated pairs show positive MLC reactions and all of them are DQA1* mismatched, suggesting that DQA1* allele typing should be used to screen samples prior to performing MLC.


HLA-DRB1 genotyping by modified PCR-RFLP method combined with group-specific primers.

We previously introduced HLA-DQA1, -DPB1 and DQB1 genotyping with the modified PCR-RFLP method using some informative restriction enzymes which have either a single cleavage site or alternatively no cleavage site in the amplified DNA region, depending on the HLA alleles, making reading of RFLP band patterns much easier. In this study, 43 HLA-DRB1 alleles, excluding DRB1*1103 and *1104 for which no restriction enzymes are available to distinguish each from the other, could be defined by this modified PCR-RFLP method combined with 7 pairs of group-specific primers. It is impossible to distinguish DRB1*0701 and DRB1*0702 as they are identical for the second exon of DRB1. For DR1-DRB1, DR2-DRB1, DR4-DRB1, DR7-DR1, DR9-DRB1, DRw10-DRB1 or DRw52 associated antigens (DR3, w11, w12, w13, w14, and DRw8)-DRB1 gene amplification, the second exon of the DRB1 gene was selectively amplified using each group-specific primer from genomic DNAs of 70 HLA-homozygous B-cell lines and healthy Japanese by PCR. Amplified DNAs were digested with restriction endonucleases and then subjected to electrophoresis assaying simply for cutting, or no cutting, of the DNA, although some alleles can be distinguished only after examination of RFLP band patterns generated and in some cases using double digestion technique with two restriction enzymes. This modified PCR-RFLP method can be successfully applied to all possible DRB1 heterozygotes, despite the fact that 15 pairs of heterozygotes among them cannot be distinguished theoretically by the PCR-SSO method, because the PCR-RFLP method can tell whether two polymorphic sites are linked to each other (cis position) or located on a different chromosome (trans position) by checking the length of RFLP bands generated with double digestion. Thus, the PCR-RFLP method is technically simple, practical and inexpensive for determination of the HLA-DRB1 alleles for routine HLA typing work.


HLA-DPB1 allele mismatches between unrelated HLA-A,B,C,DR (generic) DQA1-identical unrelated individuals with unreactive MLC.

We have used a PCR-RFLP method with one generic amplification of HLA-DPB1 second exon and 6 endonucleases to differentiate the 19 HLA-DPB1 alleles and 171 heterozygous combinations. The set of primers used in our studies produced fragment sizes different from those published before (1). The HLA-DPB1 alleles in Caucasians showed a higher frequency of DPB1*0401 and DPB1*0402, when compared to a small group of Colombians who showed a higher frequency of DPB1*0402 and DPB1*0201. We found three HLA-DPB1 alleles associated with two HLA haplotypes that result from non-random association of alleles: DPB1*0401 with HLA-A26, B38, DR4, DQA1*0301 and DPB1*0101 and DPB1*0401 with HLA-A1, B8, DR3, DQA1*0501. We also report that 70% of combinations between HLA (generic A,B,C,DR) and DQA1-identical MLC-unreactive cell mixtures showed HLA-DPB1 mismatches, suggesting that HLA-DPB1 differences are not important in MLC reactivity.


Block and modulation of cardiac Na+ channels by antiarrhythmic drugs, neurotransmitters and hormones.

The Na+ channel is an important target for the action of antiarrhythmic drugs. Application of contemporary biophysical, biochemical and molecular biological techniques have added considerably to our knowledge of its structure, function, modulation and block by antiarrhythmic drugs. The increased mortality from the use of these drugs for prophylaxis of cardiac arrhythmias has forced a re-evaluation of their use and of the entire pharmacological strategy of arrhythmia management. Gus Grant and David Wendt review recent studies on the block and modulation of cardiac Na+ channels and the place of Na+ channel blockers in future antiarrhythmic drug development.


EBV strain variation: geographical distribution and relation to disease state.

The strains of Epstein-Barr virus (EBV) were characterized in epithelial and lymphoid malignancies from geographic regions with high or low incidence. The predominant strains in nasopharyngeal carcinoma (NPC) from regions with elevated incidence were EBV type 1 in southeast Asia and Mediterranean Africa. In Alaskan Eskimos, a distinct variant of EBV type 2 was found in NPC and carcinoma of the parotid gland. This strain contained polymorphisms characteristic of the Asian EBV type 1. The strains prevalent in southeast Asia and Mediterranean Africa were also found in NPC which developed in caucasian Americans. These variants were not detected in lymphomas which developed in central Africa, Mediterranean Africa, or continental United States. These results suggest that distinct EBV strains predominate in geographic areas with elevated incidence of NPC. The detection of these distinct strains in epithelial tumors from areas of low incidence may reflect an epithelial cell tropism or pathogenicity.


Evidence that a cytoplasmically located version of a v-erbB-encoded protein can transform both fibroblasts and erythroblasts.

We previously isolated an avian erythroblastosis virus, AEV-GEE35, in which the complete extracellular and transmembrane domains of the v-erbB oncoprotein were replaced with sequences from the gag and env proteins. The GEE35 virus was capable of transforming both fibroblasts and erythroblasts as efficiently as wild-type v-erbB. Analysis of the v-erbB proteins encoded by GEE35 revealed two proteins of similar molecular weights of approximately 130,000 Da. One of these proteins was an N-linked glycosylated membrane protein, whereas the other was a cytoplasmic protein. Biochemical characterization of these two proteins revealed that the transmembrane protein has the v-erbB domain outside the cell, such that it no longer had access to its tyrosine kinase substrates. This implies that it is the cytoplasmically located v-erbB-encoded protein that is responsible for the efficient transforming ability of this virus.


Domains 1 and 2 of ICAM-1 are sufficient to bind human rhinoviruses.

The intercellular adhesion molecule-1 (ICAM-1) receptor was expressed in primary chicken embryo cells using a retroviral vector and shown to specifically bind major group human rhinoviruses (HRVs). A truncated, membrane-bound ICAM-1 protein containing N-terminal domains 1, 2, and 3 retained the ability to bind virus whereas proteins containing domains 1 and 2 or domain 1 were not expressed under these conditions. Soluble forms of ICAM-1 proteins were expressed to circumvent the reduced expression levels of shorter ICAM-1 truncations. Full-length and truncated ICAM-1 molecules containing only domains 1 and 2 were capable of neutralizing HRV binding to cells. Soluble receptors containing only domain 1 could not be recovered. Mutants of ICAM-1 lacking carbohydrate attachment sites were constructed and shown to have no effect on the ability of ICAM-1 to bind HRVs. In addition, ICAM-1 proteins expressed in the presence of tunicamycin also retained their virus binding capability. These data suggest that the N-terminal two domains of ICAM-1 are sufficient for virus interaction and that carbohydrates do not play a major role in virus binding.


Psychotropic drug use in pregnancy and perinatal death.

The psychotropic drug use in mothers to all 73 perinatally dead infants in the city of Gothenburg, Sweden, in 1985-86, was compared to a control group of mothers to 73 surviving infants. Information regarding medication in pregnancy and pre- and perinatal data was collected retrospectively. In addition, serum samples obtained in early pregnancy were screened for benzodiazepines. Eighteen case-mothers used psychotropic drugs during pregnancy compared with 7 control-mothers. The association between psychotropic drug use and perinatal death was significant (p = 0.01). Psychotropic drug use and maternal disorder were closely correlated, but within the case group there were no significant differences between mothers using or not using psychotropic drugs in terms of age, parity or smoking habits. Although the etiology of death could be discussed in the individual infant, we find it noteworthy that the use of psychotropic drugs was so frequent in the mothers of perinatally dead infants.


Effect of atrial natriuretic factor on renal prostaglandin E2 release in the anaesthetized dog.

Experiments were undertaken in two groups of barbiturate anaesthetized dogs to examine whether atrial natriuretic factor (ANF) exerts an effect on renal release of prostaglandin E2 (PGE2). In the first group, intravenous infusion of ANF (50 ng min-1 kg-1 body wt) reduced basal PGE2 release from 4.4 +/- 0.8 pmol min-1 to 1.8 +/- 0.7 pmol min-1. In the second group, intrarenal infusion of an alpha 1-adrenoceptor agonist, phenylephrine (2.5-6.75 micrograms min-1), raised PGE2 release from 2.7 +/- 0.5 pmol min-1 to 7.5 +/- 1.3 pmol min-1. During continuous alpha 1-adrenergic stimulation, intravenous infusion of ANF (100 ng min-1 kg-1 body wt) reduced PGE2 release to 3.5 +/- 1.0 pmol min-1. These results demonstrate that ANF reduces basal and alpha 1-adrenergic stimulated renal PGE2 release.


[Epidemiologic characteristics of hemorrhagic fever with renal syndrome in a military population].

In the period 1952-1990 there have been recorded 84 patients with hemorrhagic fever with renal syndrome (HFRS): 81 soldiers and 3 officers of the Y.P.A. The largest number of cases was recorded in three epidemics, 61 or 72.6%. In 94% of cases the infection occurred during camping of units. The disease appeared in all months, but 57.2% of cases occurred in June and July. The mean lethality was 2.4%, in epidemics 1.6% and as sporadic cases 4.3%. In an army unit staying for six months in HFRS focus, 9.8% of soldiers were infected by the causative agent of this infection and only in one case the clinical picture of HFRS was manifested. Serologic tests (IIF and ELISA) confirmed the diagnosis of HFRS. Virus strains of Hantaan, Puumala and Seoul groups were used as antigens.


Alpha-mediated vasoconstriction: transmembrane signalling and receptor reclassification.

Apparent differences in the usage of different calcium pools for the processes of excitation-contraction provides support for further sub-classification of the alpha-adrenoceptors in blood vessels. Presently we have addressed this question by assessing the routes of calcium utilization and the involvement of G-proteins in mediating vasoconstriction in situ.


Hepatic glutathione degradation within the sinusoids of guinea pig livers shows a periportal localization of gamma-glutamyl transferase activity.

In utilizing intact perfused guinea pig livers a probable periportal localization of gamma-glutamyl transferase (GGT) activity was apparent. Untreated livers perfused from the portal to hepatic vein had a significantly greater glutathione efflux than the same livers perfused from the hepatic to portal vein. Switching the perfusion direction also saw a significant rise in the cysteinylglycine efflux. It was apparent from the results that the efflux of glutathione degradation products from the guinea pig livers was significantly greater than those of the intact tripeptide. However, with maximal GGT inhibition glutathione accounted for 90% of the glutathione-related thiols exported from the liver with cysteine accounting for the remaining 10%. Therefore, glutathione exported from hepatocytes may act as a means of transporting its constituent amino acids. The periportal localization of GGT activity ensures that the more susceptible perivenous region faces the greatest concentration of glutathione degradation products.


[Azaspirodecanodiones in clinical psychiatry].

The authors achieve a review of some clinical and therapeutic features related to the use of azaspirodecanodiones (buspirones, gepirone, ipsapirone). Buspirone--the only one available--is a novel nonbenzodiazepine anxiolytic that shows affinity for the serotonin 1A receptor subtype, acting as a partial agonist in the serotonergic system. This review attempts to put up to date the therapeutic studies of azaspirodecanodiones--especially buspirone--in anxiety (panic disorder, generalized anxiety disorder, obsessive-compulsive disorder), depression abuse and dependence of substances and other neuropsychiatric disorders. Though its main indication is generalized anxiety disorder, it may be also useful in treating other disorders and multiple psychopathologies related to serotonergic system dysfunctions, such as depression or alcoholism. Other interesting feature of buspirone is its potential usefulness in anxious elderly patients and long-term therapy.


Seasonality of adult Culex quinquefasciatus and transmission of bancroftian filariasis in Pondicherry, south India.

Seasonal variations in biting Culex quinquefasciatus and transmission of bancroftian filariasis were investigated in Pondicherry, South India. The biting density of C. quinquefasciatus, the principal vector species, was lowest in the summer months and higher during the monsoon and winter months. The survival of the vectors as indicated by the proportion of parous mosquitoes was found to be less in the summer season. Biting mosquitoes with infective stage larvae were not encountered during the hottest months of May, June and July and the early monsoon month of August indicating seasonality of transmission. Maximum transmission took place between November and March. These findings suggest that vector control measures according to the season of transmission may produce more cost-effective results than year round control operations.


Attenuation of malaria infection, paralysis and lesions in the central nervous system by low protein diets in rats.

Young Wistar rats developed a fulminant infection when inoculated with the rodent malaria parasite Plasmodium berghei. Rats that died during the infection exhibited a progressive paralysis of the extremities, a rapidly decreasing body temperature and minute haemorrhages in the brain. Increasing the level of protein in the diet from 4 to 8 and 16% was accompanied by an increase in morbidity and mortality from 15 to 40 and 90% respectively on day 6 of the infection. Increasing the level of dietary protein also increased the reticulocyte count of the peripheral blood in infected and non-infected rats. The attenuation of the cerebral syndrome in rats fed a diet low in protein may be related to changes in erythropoiesis or to changes in immune reactivity.


Relationships between circulating S-antigens, naturally acquired antibodies to Plasmodium falciparum exoantigens and malaria attack in a mesoendemic area.

A survey involving 77 individuals living in two savannah villages near Bobo Dioulasso (Burkina Faso, West Africa), was performed in June 1987 (before), August-September (during) and January 1988 after the seasonal transmission. The clinical longitudinal study during the seasonal period permitted us to define three different groups in terms of both age and occurrence of malaria attack (MA; greater than or equal to 5000 parasites/mm3 of blood and axillary fever greater than or equal to 37.8 degrees C). The presence of circulating stable antigen (S-Ag) and the antibody responses against exoantigens (E-Ag) of Plasmodium falciparum were also evaluated at three observations periods: beginning, during and after the transmission season. The adult group (III) had the highest rates of IgG Ab to E-Ag although, IgM prevalence to E-Ag was maximal in the group II (individuals with no malaria attack and age less than or equal to 15 years old). Group I (persons with less than or equal to 15 years old and who contracted at least one MA) did not have any S-Ag at the first observation period and showed the lowest rate of antibodies to E-Ag. The probability of occurrence of an MA calculated from these parameters at the beginning of the transmission period were correct in 78.9% of the cases in children (Groups I & II) and in 71.8% of adults during the subsequent transmission period. Therefore these values could be used for evaluating the probability of occurrence of a clinical MA during the transmission period in a mesoendemic area. S-Ag and antibodies to E-Ag could participate positively in the mechanisms involved in the development of the immune status.


Eating habits of east Asian people and transmission of taeniasis.

In order to understand the role of raw meat and viscera eating habits in the transmission of taeniasis in Asian countries, 1502 infected aborigines in ten mountainous districts/towns of six counties in Taiwan, 58 infected persons in two villages on Cheju Island, Korea, and 97 cases in Ambarita District on Samosir Island, North Sumatra, Indonesia were studied during the field surveys. All infected Taiwan aborigines had the habit of eating raw meat and viscera of wild and/or domestic animals. Among these aborigines, 73% ate wild boar, 66% flying squirrel, 65% wild goat, 56% muntjac, 49% wild rats, 46% monkey, 38% hare, 20% civet-cats, 18% weasel, 17% pheasant, 14% squirrel, 4% grouse, 1% deer, 1% snake, less than 1% bamboo partridge, less than 1% frog, less than 1% bear, less than 1% dog, and less than 1% fox. Of the 58 infected persons with Taenia on Cheju Island, Korea, 72% ate raw meat and/or viscera of pig and cattle, 19% raw pork only, and 9% raw beef only. Among 12 infected persons infected with T. saginata-like tapeworms, 7 had eaten raw pork, 2 raw beef and pork and 3 raw pork. Almost all of the 97 cases of taeniasis on Samosir Island of North Sumatra, Indonesia, had eaten only undercooked pork. Eleven of 15 cases were found to be infected with T. saginata-like tapeworms. Eating habits observed suggest an unusual way of transmission of Taenia in East Asia.


Schistosoma haematobium infection in pregnancy.

Due to the economical lack of safe drugs in a remote area of Ghana (Bawku District) to treat Schistosoma haematobium infection during pregnancy, the spontaneous outcome of the pregnancy in women with proved S. haematobium infection was compared with a control group (average hospital delivery). In a survey of 200 pregnant women, we found a prevalence of S. haematobium of 4.5%. From the original collection of 41 infected pregnant women we could follow 23 up to delivery. This group showed a higher number of preterm (less than 37 weeks) deliveries, 34.8% vs. 23.8% in the control group. The birthweights in term deliveries (greater than 37 weeks) were not significantly different (3012 g vs. 3103 g). In the preterm deliveries the birthweight was significantly lower in the infected group (1768 g vs. 2457 g, p less than 0.005).


A decade of plague epidemiology and control in the western Usambara mountains, north-east Tanzania.

Outbreaks of human plague have been occurring in the Western Usambara mountains since 1980, involving many cases and deaths. Epidemiological surveys and control activities were carried out from June 1980 to May 1990. Rodents were trapped live, identified and serologically tested for plague, using the passive haemagglutination and passive haemagglutination inhibition tests. Rodent fleas were collected, processed, identified and counted. House fleas were caught with light traps and similarly treated. People and domestic carnivores were serologically tested for the disease. Various plague control measures were undertaken. A total of 2433 animals, 2254 rodent fleas and 1366 house fleas were collected. Average indices of rodent and house fleas were 0.93 and 5.38 respectively. Rattus rattus and Mastomys natalensis were the most abundant rodent species. Xenopsylla brasiliensis and Dinopsyllus lypusus were their commonest flea ectoparasites while Pulex irritans was the major house flea. Of 2044 rodent, 1880 human and 176 dog sera tested, 5.5%, 0.5% and 6.3% respectively were positive. It was concluded that plague was active in the focus despite the control measures and that common reservoirs and efficient vectors were present. It was suggested that dogs were probably involved in the epidemiology of the disease, that P. irritans was not susceptible to the insecticide used and that the flea was probably involved in murine plague transmission. Bacteriological research on the causative agent to establish the nature of its long persistence in the area and maintenance of a surveillance service are recommended.


Inhibition of the growth of Plasmodium falciparum and Plasmodium berghei in vitro by an extract of Cochlospermum angolense (Welw.).

An extract of Cochlospermum angolense (Welw.) is used in the traditional medicine of Angola for the therapy of icterus and for the prophylaxis of malaria. From the roots of this plant red crystalline substances have been isolated and tested for their effect on Plasmodium falciparum in vitro and on the DNA and protein synthesis of Plasmodium berghei. The multiplication of P. falciparum was decreased to 50% of the control in the presence of 10 micrograms/ml extracted material and there was a total inhibition at a concentration of 50 micrograms/ml. If mice erythrocytes infected by P. berghei were incubated for 6 h with 25 micrograms/ml of the extract DNA synthesis was depressed to nearly background level. And, even more important, this effect could be demonstrated immediately. On the contrary, protein synthesis continued for at least 90 min at a reduced rate and stopped then. The results obtained show the direct antiparasitic effect of the substances extracted from C. angolense. The activity seems to be directed against DNA synthesis.


Nosocomial fungal infections--study of the possible role of cockroaches (Blattella germanica) as vectors.

A variety of fungi of medical importance were recovered from cockroaches (Blattella germanica) collected from hospital wards (159) and residential areas (128) in different seasons. The fungi isolated were various species of Candida, Rhizopus, Mucor, Alternaria and Aspergillus. Candida spp. were the fungi isolated in highest percentage from hospital and residential area.


Sequential infection of tsetse flies with Trypanosoma congolense and Trypanosoma brucei.

The question whether tsetse flies can be experimentally infected with more than one trypanosome species or strain by sequential feeding was investigated using DNA probe technology to identify directly the small numbers of trypanosomes in the fly gut. Bloodstream form trypanosomes of Trypanosoma congolense or T. brucei ssp. were used for initial infection, followed by sequential feeds using either T. congolense or T. brucei ssp. Midgut trypanosome populations were subsequently analysed by hybridising dot blots with species-specific DNA probes. Two different T. brucei stocks were also fed in succession and the midgut trypanosome populations analysed by molecular karyotype. Contrary to expectations from previous reports, it was comparatively easy to superinfect flies with a second trypanosome species or stock, although the presence of trypanosomes already in the gut did not aid establishment of those incoming. Thus, to develop a mixed infection, a prerequisite for trypanosome mating, flies do not necessarily have to pick up both parental trypanosomes on their first feed.


Balloon angioplasty of the aorta in Takayasu's arteritis: initial and long-term results.

Percutaneous transluminal balloon angioplasty for stenosis of the aorta was performed in 36 patients with Takayasu's arteritis (age range, 8 to 36 years; mean, 19.1 +/- 7.7 years). Balloon dilatation was successful in 34 patients and resulted in a decrease in the mean peak systolic pressure gradient (PSG) from 75.2 +/- 29.1 mm Hg to 24.8 +/- 19 mm Hg (p less than 0.001) and a mean increase in the diameter of the stenosed segments from 4.5 +/- 2.2 mm to 9.6 +/- 3.8 mm (p less than 0.001). Hemodynamic and angiographic restudy, which was performed in 20 patients at a mean follow-up period of 7.7 +/- 4.1 months (range, 3 to 24 months), showed a further decrease in PSG (greater than or equal to 15 mm Hg) in seven patients (from 40.0 +/- 11.2 mm Hg to 15.7 +/- 10.2 mm Hg; p less than 0.01), no significant change in PSG in 12 patients (17.1 +/- 13.6 mm Hg vs 16.6 +/- 12.7 mm Hg; p = NS), and an increase in PSG from 15 mm Hg to 85 mm Hg in one patient. The patient who showed restenosis underwent successful redilatation. Six patients who underwent late recatheterization and angiography at 36 to 60 months (mean, 43 +/- 9.4 months) show continued relief of stenosis (mean PSG, 8.8 +/- 7.8 mm Hg). Patients with short-segment (less than 4 cm) stenosis experience more relief than patients with long-segment (greater than or equal to 4 cm) stenosis (residual PSG, 18.6 +/- 8.2 mm Hg vs 40 +/- 16 mm Hg; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)


Differential effects of xamoterol and verapamil on ventricular rate regulation in patients with chronic atrial fibrillation.

In a placebo-controlled study the effects on ventricular rate regulation and exercise performance of xamoterol, 100 mg two times a day and 200 mg two times a day, and slow-release verapamil, 240 mg once a day, were assessed in 21 patients with chronic atrial fibrillation. The mean ventricular rate from noon to 6:00 PM was 101 +/- 20 beats/min with placebo, 95 +/- 17 beats/min with xamoterol 100 mg two times a day (not significant), 90 +/- 16 beats/min with xamoterol 200 mg two times a day (p less than 0.001 vs placebo) and 78 +/- 19 beats/min with verapamil (p less than 0.001 vs each other treatment). The mean ventricular rate from midnight to 6:00 AM was 69 +/- 16 beats/min with placebo, increased with xamoterol 100 mg two times a day and 200 mg two times a day to 75 +/- 15 beats/min and 74 +/- 16 beats/min, respectively (p less than 0.001 vs placebo), but decreased with verapamil to 62 +/- 15 beats/min (p less than 0.001 vs each other treatment). The number of ventricular pauses greater than 2.0 seconds was increased by verapamil (p less than 0.05). All active treatments reduced exercise ventricular rates (p less than 0.001), but the decrease was more pronounced with verapamil. The anaerobic threshold was reached significantly earlier with verapamil than with placebo (72 +/- 32 W vs 79 +/- 37 W; p less than 0.01). Xamoterol is preferable to verapamil for treatment of patients with chronic atrial fibrillation who exhibit both bradycardia at rest and excessive tachycardia during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)


The effects of beta 1- and beta 2-adrenergic blockade and calcium channel blockade on postresuscitation electrolyte changes.

We have previously reported in dogs after ventricular fibrillation that (1) potassium and calcium levels decrease and magnesium and glucose increase, (2) all values return to control levels by 3 hours, and (3) propranolol blocks the changes in potassium, magnesium, and glucose but not calcium. The purpose of this study was to evaluate the beta 1- and beta 2-selectivity of changes in potassium, magnesium, and glucose and assess the response of the change in calcium to calcium channel blockade. Before initiating ventricular fibrillation, we pretreated dogs with an intravenous solution of either normal saline, metoprolol, ICI 118551 (two doses), or diltiazem. After a 2-minute episode of ventricular fibrillation, dogs were resuscitated. Baseline electrolyte measurements were obtained before ventricular fibrillation and sequentially for 3 hours after fibrillation. The saline-treated control group had a maximal decrease in the serum potassium level of 0.5 +/- 0.2 mEq/L. High-dose ICI 118551 reduced this decrease to 0.3 +/- 0.3 mEq/L (p = 0.055), but the other three groups showed no difference compared with the control group. Magnesium increased in the saline control group by 0.2 +/- 0.1 mEq/L. This increase was partially reduced by high-dose ICI 118551 to 0.1 +/- 0.1 (p = 0.055) but not by the other drugs. Glucose increased to 40 +/- 13 mg/dl in the saline control group. This increase was partially reduced by high-dose ICI 118551 to 23 +/- 6 mg/dl (p = 0.007) but not by the other drugs. Calcium showed a maximal decrease of 0.6 +/- 0.3 mg/dl in the control group. This decrease was not attenuated by any of the drugs.(ABSTRACT TRUNCATED AT 250 WORDS)


The influence of topography on the cognitive and psychopathological effects of tardive dyskinesia.

The purpose of the study was to investigate the influence of the topography of dyskinetic movements on their effect on cognitive impairment and negative symptoms. Eighty-four inpatients who satisfied DSM-III-R criteria for schizophrenia were rated for tardive dyskinesia, akathisia, and drug-induced parkinsonism, as well as negative symptoms, with the Scale for the Assessment of Negative Symptoms and for cognitive state with the Mini-Mental State examination. The subjects were then divided into those without tardive dyskinesia (N = 45), those with orofacial dyskinesia (N = 19), and those with limb-truncal dyskinesia (N = 20). Differences among the groups were assessed with multiple analysis of covariance (MANCOVA), with age, akathisia, and drug-induced parkinsonism ratings as the covariates. Post hoc Spjotvoll and Stoline tests were then undertaken. MANCOVA revealed a significant difference among the groups. Post hoc tests showed that the group with limb-truncal dyskinesia had significantly lower scores on the Mini-Mental State Examination and higher scores on the Scale for the Assessment of Negative Symptoms. The group with orofacial dyskinesia was significantly different from the nondyskinetic group only on the total score for the Scale for the Assessment of Negative Symptoms and the attention subscale. There were no significant differences between the dyskinetic groups. After correction for the important confounding variables of age, akathisia, and drug-induced parkinsonism scores, those with limb-truncal and, to a lesser degree, orofacial dyskinesia differed significantly from nondyskinetic comparison subjects in ratings of cognitive impairment and negative symptoms.


Molecular basis of clinical heterogeneity in neuroblastoma.

Neuroblastomas are heterogeneous in terms of both their genotype and their clinical behavior. Recent studies suggest that these two features are related, and that the genotype frequently is predictive of response to treatment or the outcome of the patient. The genetic abnormalities that are characteristic of certain neuroblastomas include: (a) loss of heterozygosity (LOH) for the short arm of chromosome 1, including band 1p36; (b) amplification of the N-myc protooncogene; and (c) hyperdiploidy, or near-triploidy, determined either by flow cytometry or by karyotype. Hyperdiploidy is associated with lower stages of the tumor and with a favorable outcome in infants. However, LOH for chromosome 1 (band p36) and N-myc amplification are more common in patients over 1 year of age who have advanced stages of the tumor. Based on analysis of neuroblastomas for these genetic abnormalities, three distinct genetic subsets can be identified. The first is characterized by a hyperdiploid or near-triploid modal karyotype, with few, if any, cytogenetic rearrangements. These patients are generally less than 1 year of age, they have localized tumors, and have a good prognosis. The second genetic subset has a near-diploid karyotype, but with no consistent abnormality identified to date. They are generally older patients with tumors in the more advanced stages that progress slowly and are often fatal. Patients in the third group of genetic abnormalities have a near-diploid or tetraploid karyotype, with deletions or loss of heterozygosity for 1p36, amplification of N-myc, or both. These patients are generally older; they have advanced stage tumors that are rapidly progressive.(ABSTRACT TRUNCATED AT 250 WORDS)


The associations of alcohol drinking and drinking cessation to measures of the immune system in middle-aged men.

To estimate the association between the immunologic responses of the cell-mediated and humoral systems and alcohol drinking, we used data from the Vietnam Experience Study conducted by the Centers for Disease Control. That study, conducted from 1985 to 1986, was based on a random sample of 4462 male, Vietnam-era, U.S. veterans. By using linear regression, we evaluated how (1) the number of alcoholic drinks the subjects consumed per month and (2) the drinking cessation of certain subjects were associated with their relative and absolute T, B, CD4, and CD8 lymphocyte counts and immunoglobulin A (IgA), IgM, and IgG levels. We used geometric means and percentage differences in geometric means of immune status to measure the associations and adjusted these values to account for the effect of covariates. The results indicated that measures of immune status differed among the drinking categories and that, generally, the differences changed after adjustment for covariates. These differences consisted, as alcohol consumption increased, of higher IgA and IgM levels, relative T and CD4 lymphocytes, and the ratio of CD4 to CD8 cells, and of lower IgG levels, relative B and CD8 lymphocytes, absolute lymphocyte, and lymphocyte subset counts after adjusting for other covariates. Among former drinkers, we found no clear-cut pattern in measures of immunity for a few years after cessation and then found that values of former drinkers tended to return toward values of nondrinkers as they continued to abstain.


Alcoholism and the D2 receptor gene.

The allelic association of the human dopamine D2 receptor gene and alcoholism was evaluated in 20 male alcoholics and 20 controls (sex, race, and geographic place of birth matched). This study further examines the issue of alcoholism severity and A1 allele frequency. No difference in A1 allele frequency was observed between these two groups. Similarly, no relationship between alcoholism severity and A1 frequency within the alcoholics was demonstrated.


Lack of interaction between propofol and vecuronium.

We estimated the potency of vecuronium and measured the onset and duration of its action during total intravenous anesthesia with propofol to examine the possibility of any interaction between these two drugs. Propofol infusion was administered according to a three-step dosage scheme, and neuromuscular block was monitored by measuring the force of contraction of the adductor pollicis muscle after single-twitch stimulation of the ulnar nerve at 0.1 Hz. A control group of patients were similarly studied during anesthesia with thiopental, nitrous oxide, oxygen, and fentanyl. The ED50 and ED95 (dose required to produce a 50% and 95% depression of twitch tension, respectively) of vecuronium in patients given total intravenous anesthesia (n = 24) were 24 (22-27, 95% confidence limits) and 41 (37-48, 95% confidence limits) micrograms/kg, respectively, and in the control group (n = 24), 20 (17-24) and 39 (34-37) micrograms/kg, respectively. The onset of action of an 80-micrograms/kg dose (2 x ED95) of vecuronium was 3.6 +/- 1.2 and 4.1 +/- 1.7 min (mean +/- SD), in the propofol (n = 10) and control (n = 10) groups, respectively. The respective times to recovery of the twitch height to 25% of control and the recovery indices (25%-75% recovery of twitch height) in the propofol versus control groups were 28.3 +/- 6.6 and 28.0 +/- 1.7 min and 13.3 +/- 6.8 and 15.4 +/- 11.9 min, respectively. There were no significant differences in any of the measured variables between the propofol and control groups, indicating the lack of any interaction between propofol and vecuronium.


Intraoperative monitoring of tibialis anterior muscle motor evoked responses to transcranial electrical stimulation during partial neuromuscular blockade.

We studied the feasibility of recording motor evoked responses to transcranial electrical stimulation (tce-MERs) during partial neuromuscular blockade (NMB). In 11 patients, compound muscle action potentials were recorded from the tibialis anterior muscle in response to transcranial electrical stimulation during various levels of vecuronium-induced NMB. The level of NMB was assessed by accelerometry of the adductor pollicis muscle after train-of-four stimulation of the ulnar nerve. The compound muscle action potential was also recorded from the tibialis anterior muscle after direct stimulation of the peroneal nerve (M-response) as an alternative means of assessing the degree of NMB. In all patients, tce-MERs could be recorded reliably during anesthesia with N2O and a continuous infusion of sufentanil (0.5 micrograms.kg-1.h-1). An intact train-of-four was present in all patients, and the amplitude of the first twitch was recorded and designated as the control value. Before administration of vecuronium, the M-response amplitude was 9.6 +/- 3.6 (mean +/- SD) mV, and the tce-MER amplitude was 1.21 +/- 0.66 mV. Although administration of vecuronium (0.05 mg/kg) resulted in loss of the mechanical adductor pollicis response in 8 of the 11 patients, the M-response and the tce-MER remained recordable. Subsequently, during an infusion of vecuronium, adjusted to maintain one or two mechanical responses to train-of-four stimulation, the average M-response to peroneal nerve stimulation was 5.2 +/- 2.5 mV (53% of the control value), and tce-MER amplitude was 0.59 +/- 0.36 mV (59% of the control value).(ABSTRACT TRUNCATED AT 250 WORDS)


[Portal blood levels of mitomycin C after intraperitoneal administration].

Portal blood levels of mitomycin C (MMC) were measured after intraperitoneal administration of 10 or 20 mg of mitomycin C following pancreatoduodenectomy. The portal concentration of MMC increased rapidly to the maximum concentration of 826 +/- 364 ng/ml at 5 minutes after administration, when the dosage was 20 mg (four cases). The peripheral blood levels followed the portal levels and the maximum concentration was 397 +/- 123 ng/ml at 15 minutes. Then the MMC levels of both portal and peripheral blood decreased gradually, but concentration higher than 100 ng/ml was maintained for 90 minutes after administration. In four patients given 10 mg of MMC, the patterns of the blood levels were similar, but the concentration was lower than in the group given 20 mg. In both groups, the AUC values were higher in portal than in peripheral blood. MMC administered intraperitoneally was absorbed rapidly through portal circulation and a high MMC level of portal blood was obtained. Therefore, it would prevent the dissemination of cancer cells into the liver which may well occur during operation for pancreatic carcinoma.


Cryptorchidism: incidence and sperm quality in infertile men.

In a population of 8500 men attending the andrology outpatient clinic, 200 men (2.35%) were recorded as having some disturbances with the descent of the testes into the scrotum. Medical history of the patients revealed that 51 underwent unilateral orchidopexy; 40 bilateral orchidopexy; and 24 were treated with human chorionic gonadotropin in order to induce descent of their testes. In addition, 6 patients reported spontaneous descent of the testes, and 13 others were found to be unilaterally cryptorchid upon physical examination. Results of semen analysis, hormonal profile, testes position, and testicular volume were compared to those of 105 proven fertile men. The major finding of this study shows that post-partum undescended testes suffer from primary Sertoli cell malfunction as reflected by elevated serum follicle stimulating hormone levels. Serum luteinizing hormone and testosterone levels were within the normal range. Surgical descent of the testes did not improve sperm production, proved by low sperm quality of all the study groups, compared to the cryptorchid group. Among the patients who were operated on, no correlation was found between age at operation and semen variables. All groups showed poor sperm quality which can be defined as oligoteratoasthenozoospermia. The degree of spermatogenic damage was in the following order of diagnosis or treatment: bilateral orchidopexy greater than cryptorchid testes greater than hormonal treatment greater than unilateral orchidopexy greater than late spontaneous descent of the testes. Thus, it is advisable to postpone surgical treatment of cryptorchidism and apply this only after a waiting period, and if the hormonal approach has failed to descend the testis.


[Rhythmogenic cardiomyopathies of atrial origin in children. Myth or reality?].

Incessant, rapid, supraventricular tachycardia may be complicated by cardiac failure with ventricular dilatation and hypokinetic wall motion on echocardiography: so-called tachycardia-induced cardiomyopathy. The diagnosis is simple when the cardiac rhythm is not sinus rhythm. The authors report the cases of 4 children aged 7 months to 12 years, referred for diagnosis and treatment of apparently primary cardiomyopathy. The findings of spontaneous or vagally-induced atrioventricular conduction defects, a permanently rapid atrial rhythm though influenced by 24 hour variations, or periodic abnormal rate increases, suggested myocardial dysfunction due to an ectopic atrial tachycardia. This was an essential step in management as the control of the tachycardia by amiodarone or betablocker therapy resulted in regression of symptoms and normalisation of left ventricular function. However, some atrial tachycardias are very resistant to medical treatment and, in such cases, there should be no hesitation in using more radical approaches, surgery or ablation, even and especially in patients with severe cardiac failure. In conclusion, apparently primary dilated cardiomyopathy in children may be due to chronic atrial arrhythmia and it is essential to perform at least Holter monitoring in order not to miss this diagnosis.


[Drug therapy of acute myocardial infarction without cardiogenic shock and thrombolytic therapy excluded].

Myocardial infarction is responsible for 25,000 deaths per year in France and is a real problem of public health. The management of patients victims of this condition is an important feature of medical practice. Thrombolytic therapy has resulted in significant improvements in the reduction of the size of the infarct, in the conservation of left ventricular function and in the reduction of mortality. Treatment of the acute phase of myocardial infarction, especially when there are contra-indications to thrombolysis, comprises other approaches, some of which are old, which are reviewed in the light of the results of the latest large scale therapeutic trials.


[Electric stability of the heart after myocardial infarction: role of anti-arrhythmia agents during postinfarction].

Electrical instability of the heart after myocardial infarction threatens surviving patients with sudden death from a severe ventricular arrhythmia. These arrhythmic complications are usually the result of several factors: an arrhythmogenic substrate corresponding to the ischaemic myocardium, a trigger factor (usually a ventricular extrasystole) and other predisposing factors (autonomic nervous system, electrolyte imbalance, activation of the renin-angiotensin system). Risk stratification of electrical instability combines noninvasive (Holter, exercise testing, signal averaged electrocardiography, study of the variability of the heart rate, radionuclide or echocardiographic evaluation of the left ventricular ejection fraction) and invasive investigations (coronary angiography and even programmed ventricular stimulation). The presence of late ventricular potentials, a low ejection fraction and/or a ventricular arrhythmia on Holter monitoring identifies a high risk subgroup. Although the assessment of electrical instability is better than it used to be, pharmacological prevention remains disappointing. Class I antiarrhythmics are ineffective or dangerous. The efficacy of Class III antiarrhythmics is uncertain and only the betablockers seem to have any beneficial effects on this post-infarction electrical instability.


Neurohumoral changes and the inducibility of ventricular tachycardias: effect of early reperfusion on the ischemic porcine myocardium.

The effects of early reperfusion were studied in closed-chest pigs subjected to either 45 min or 3 hr of regional ischemia. Myocardial enzyme release during early reperfusion and electrophysiological stability after two weeks were assessed. Coronary artery occlusion durations of 3 hr and early reperfusion after 45 min were compared. The creatine phosphokinase levels in the coronary effluent were lower after early reperfusion (p less than 0.001). Moreover, in the early reperfusion group, the coronary sinus catecholamine and purine levels rose to higher values than in the 3 hr group. The plasma levels of catecholamines and the plasma renin activity increased rapidly but transiently at reperfusion in the 45 min group. Both the rate-pressure product and the heart rate were elevated at the end of the reperfusion period (p less than 0.001) in the 45 min group. Survival for two weeks was 3 out of 6 animals in the 3 hr group and 5 out of 8 in the 45 min group. In all but one surviving animal, sustained ventricular tachycardias were inducible by programmed stimulation. Abnormally low QRS amplitudes and delayed potentials were found in the signal-averaged electrocardiogram in the early reperfusion group only. In conclusion, early reperfusion causes a reduction of myocardial tissue damage, but simultaneously, neurohumoral parameters showed a greater activation of the sympathetic nervous system and the renin-angiotensin system apparently causing a deleterious increase in oxygen consumption. Therefore, this injurious component of early reperfusion might prevent the potentially beneficial effects of a reduced tissue damage on survival or late arrhythmias.


The pharmacology of 1-phenyl-2-propylamino-pentane (PPAP), a deprenyl-derived new spectrum psychostimulant.

The peculiar tyramine uptake inhibitory effect of (-)deprenyl prompted structure-activity relationship studies aiming to develop new spectrum central nervous system stimulants which are devoid of MAO inhibitory potency and operate de facto as indirectly acting, nonreleasing sympathomimetics. Of the derivatives synthesized for this purpose, 1-phenyl-2-propylaminopentane (PPAP) was selected as the reference substance and its pharmacological spectrum is presented. PPAP is taken up by the catecholamine axon terminal membrane and the vesicular membrane but it is devoid of catecholamine-releasing property. As a result, PPAP is, by interference, a potent inhibitor of the uptake of indirectly acting sympathomimetic releasers and of the catecholamine transmitters. This was proved, on the one hand, by measuring the uptake of [14C]PPAP into the catecholaminergic axon terminals and the inhibition of the uptake of [3H]noradrenaline and [3H]dopamine by PPAP in the rat brain, and, on the other hand, on the pulmonary artery strip of the rabbit and, in vivo, using the rat nictitating membrane as a detector. PPAP increases motility at 2 mg/kg and, in contrast to amphetamine, inhibits it at very high doses (50 mg/kg) only. A two-sided antagonism in the motility-increasing effect between PPAP and amphetamine and, more pronounced, between PPAP and mazindol was detected. PPAP is substantially less effective in inducing stereotyped behavior than either amphetamine or methamphetamine. PPAP facilitates learning and retention, is highly potent in antagonizing the tetrabenazine-induced depression in behavioral tests and is very effective in the forced swimming test. Whereas amphetamines facilitate performance in a very narrow range of low doses, which turns, at a modest elevation of the dose, into the opposite effect, PPAP improves performance within a reasonably broad dose range. Based on the peculiar pharmacological profile of PPAP, its potential usefulness in depression, in Alzheimer's disease and in attention-deficit-hyperkinetic disorder seems to be plausible.


[Isosorbide dinitrate in the treatment of coronary insufficiency].

The improvement of our understanding of the pharmacology of nitrate derivatives has allowed rationalisation of their use in the treatment of coronary artery disease. The comprehension of the evolution of the sensitivity of the vessel wall to nitrate vasodilatation with time has enabled definition of a rhythm of administration which preserves therapeutic efficacy: a daily therapeutic window of 8 to 10 hours. The introduction of new galenic forms (slow release oral preparations and transdermal patches) facilitates the practical application of the "optimal" pharmacokinetic profile. A single daily dose of slow release ISDN is effective in controlled trials versus placebo in the treatment of chronic stable angina. Many clinical trials have also shown the synergy of the anti-anginal effects of ISDN and betablockers, both in single dose studies and during prolonged administration. These therapeutic windows are not adapted to the treatment of acute coronary insufficiency (unstable angina, myocardial infarction); however, it has recently been shown that the use of small, fixed doses of intravenous ISDN over a 3 day period is usually adequate for controlling acute coronary insufficiency and is not associated with the phenomenon of tolerance.


Dopamine-induced contractile responses of the rat anococcygeus muscle.

In the rat anococcygeus muscle both dopamine and noradrenaline induced concentration-dependent contractile responses. The alpha 1-antagonist prazosin inhibited both dopamine and noradrenaline responses, whereas the alpha 2-antagonist yohimbine influenced noradrenaline-mediated responses only. The concentration-effect curves for dopamine were shifted to the right in presence of cocaine or after treatment with reserpine and alpha-methyl-p-tyrosine. When the tissues were previously exposed to 6-hydroxydopamine, the tyramine-induced contractile effect was abolished. Dopamine-induced concentration-effect curves were markedly shifted to the right. Treatment with 6-hydroxydopamine and reserpine did not modify the concentration-effect curves to noradrenaline. Our results indicate that dopamine has a dual effect: a partial effect due to an indirect sympathomimetic action and a partial effect due to the interaction with postjunctional receptors.


Studies on the active centre of Rhodotorula gracilis D-amino acid oxidase and comparison with pig kidney enzyme.

D-Amino acid oxidase (EC 1.4.3.3) from Rhodotorula gracilis has been reconstituted with 8-chloro-, 8-mercapto-, 6-hydroxy-, 2-thio-, 5-deaza- and 1-deaza-FAD, and the properties of the resulting complexes have been studied and compared with those of the correspondingly modified pig kidney D-amino acid oxidases. Binding appears to be tight for most analogues, at least as tight as for native FAD (approximately 10(-8) M). 8-Mercapto- and 6-hydroxy-FAD bind in their para- and ortho-quinoid forms respectively to yeast D-amino acid oxidase, inferring the presence of a positive charge near the flavin N(1) position, as in the case of the mammalian enzyme. On the other hand, important differences in active-site microenvironment emerge: solvent accessibility to flavin position 8 is drastically restricted in yeast D-amino acid oxidase as indicated by the unreactivity of 8-chloro- and 8-mercapto-FAD enzyme with thiolates and alkylating agents. Significantly different microenvironments are also likely to occur around the flavin positions N(1)-C(2) = 0, N(3)-H and N(5). This is deduced from the differences in interaction of the two proteins with 1-deaza-FAD, 5-deaza-FAD and 2-thio-FAD and from the properties of the respective complexes. The same re-side flavin stereospecificity as shown by the mammalian enzyme was determined for the yeast enzyme using 8-hydroxy-5-deaza-FAD. Thus we can deduce the presence of a similar pattern of functional groups at the active centres of the two enzymes, while the fine tuning of specificity and regulation correlate with environmental differences at specific flavin loci.


Effectors of ATP-sensitive K+ channels inhibit the regulatory effects of somatostatin and GH-releasing factor on growth hormone secretion.

Somatostatin inhibition of growth hormone (GH) secretion from adenohypophysis cells in culture was antagonized by the antidiabetic sulfonylurea glipizide (K0.5 = 10 +/- 5 nM). Although all cells that hyperpolarize with somatostatin have ATP-sensitive K+ channels, the antagonistic actions of the hormone and of the antidiabetic drug are due to effects on different types of K+ channels. Diazoxide, an opener of ATP-sensitive K+ channels, abolished the increase of intracellular Ca2+ provoked by growth hormone releasing factor (GRF) and induced inhibition of GRF stimulated GH secretion (K0.5 = 138 microM). This inhibition by diazoxide was largely suppressed by glipizide which blocked the ATP-sensitive K+ channels opened by diazoxide. In summary, hormonal activation of GH secretion is inhibited by openers of ATP-sensitive K+ channels, while hormonal inhibition of GH secretion is suppressed by blockers of ATP-sensitive K+ channels.


Effect of liposomes on P-glycoprotein function in multidrug resistant cells.

Presentation of doxorubicin in liposomes has shown to enhance the sensitivity of multidrug resistant CH LZ cells to the drug (Thierry et al. Cancer Commun. 1:311-316, 1989). We confirmed that liposomally encapsulated doxorubicin may partially overcome multidrug resistance in the human ovarian carcinoma SKVLB cell line and that this effect is, at least in part, due to an increase of cellular drug accumulation. When used at high concentration, empty liposomes appear to be specifically cytotoxic in the MDR SKVLB and CH LZ cells. As observed with certain multidrug resistance modulators, empty liposomes inhibited the specific [3H]-vincristine binding to P-glycoprotein-enriched membranes isolated from CH LZ cells (60% at 0.2 mg lipid/ml). Our data suggest that liposomes may alter the P-glycoprotein function by direct interaction.


Activation of human multidrug resistance-1 gene promoter in response to heat shock stress.

The multidrug resistance (MDR1) gene encodes a P-glycoprotein, which catalyzes the energy-dependent efflux of anticancer agents. Various environmental stresses including heat shock can induce the expression of endogenous MDR1 genes. In order to study the regulatory mechanisms of MDR1 gene expression, we have established human cancer KB cell lines which could stably integrate bacterial chloramphenicol acetyltransferase (CAT) gene driven by various lengths of the MDR1 promoter. Kst-6 has an integrated plasmid, pMDRCAT1, containing the human MDR1 promoter of -2 kilobases. The MDR1 gene promoter contains a typical heat shock element (HSE) motif located -152 bp to -178 bp from the initiation site. Heat shock at 45 degrees C for 90 min significantly induced CAT activity in Kst-6 cells. Northern blot analysis showed a 4-5 fold increase in CAT mRNA levels in Kst-6 cells. Deletion analysis of the MDR1 promoter demonstrated that the induction of CAT activity was observed in Kxh-14 cells containing a HSE-deleted MDR1 promoter construct, pMDRCAT7. However, further deletion analysis showed that heat shock could not induce CAT activity in Khp-1 cells containing -76 approximately +121 base sequence of the promoter, suggesting that a new heat shock responsible element was located at between -136 and -76. Gel shift assay showed that the heat shock factor (HSF) could bind to the HSE motif located at -152 bp to -178 bp in the MDR1 promoter. We also found that one distinct DNA-protein complex formed specifically within the MDR1 promoter region -99 to -66 was not significantly increased, but relatively more stabilized under mild denaturing condition in the nuclear extract of heat-shocked cells. In our present assay system, activation of the MDR1 promoter in response to heat shock appears to be mediated through both a new heat shock responsive element and MDR1 specific transcription factor.


de novo biosynthesis of heme offers a new chemotherapeutic target in the human malarial parasite.

The human malarial parasite, Plasmodium falciparum, has been found to synthesize heme de novo, despite the accumulation of large quantities of polymeric heme derived from the hemoglobin of the red cell host. The parasite delta-aminolevulinate dehydrase level is significantly lower than that of the host and its inhibition by succinylacetone leads to inhibition of parasite protein synthesis and viability.


Insulin-responsive tyrosine aminotransferase transcription requires multiple promoter regions.

This study used transient transfection analysis to determine the DNA regions which mediate basal and insulin-sensitive transcription from the gene encoding tyrosine aminotransferase (TAT; EC 2.6.1.5). Basal expression requires at least parts of two regions: a region at -3600 and a region from -208 to + 62. Insulin sensitivity requires at least one region of the promoter not required for basal expression. Thus, insulin cannot act solely by direct modification of any of the components required for basal transcription. Previous results from this laboratory suggest that the insulin effects on basal and glucocorticoid-induced TAT transcription require different regions of the proximal promoter.