The antimalarial effect of iron chelators: studies in animal models and in humans with mild falciparum malaria. In this study we explore the antimalarial effects of 3-hydroxypyridin-4-ones (CP compounds), a family of bidentate orally effective iron chelators in experimental animal systems in vivo and in vitro, and examine whether the iron chelator deferoxamine (DF) is active against human infection with P. falciparum. There was direct relation between lipid solubility of the CP compounds, which would facilitate membrane transit, and their in vivo antimalarial action, suggesting direct intracellular iron chelation as the most likely explantation for the antimalarial effect of iron chelators. Results of the double-blind, placebo controlled trial of DF in humans with asymptomatic parasitemia provided unequivocal evidence that this iron-chelating agent has antimalarial activity. Depriving the parasite of a metabolically important source of iron may represent a novel approach to antimalarial drug development. DF is a relatively ineffective intraerythrocytic chelator, and our data indicate that other orally effective iron chelators may have superior antimalarial activity in vivo. A systematic screening of available iron chelating drugs may result in the identification of potentially useful antimalarial compounds.


A casein kinase-like kinase phosphorylates beta-tubulin and may be a microtubule-associated protein. The hypothesis that casein kinase II (CKII) is a microtubule-associated protein kinase was investigated using a neuronal cell line and bovine brain. Heparin, an inhibitor of CKII, inhibited the phosphorylation of a PC12 cytosolic protein whose molecular weight was similar to that of beta-tubulin. Partially purified PC12 CKII was immunoreactive to an antibody directed against bovine CKII and was able to phosphorylate purified beta-tubulin in a heparin-inhibitable manner when the concentration of tubulin was less than 50 micrograms/ml. To better determine if CKII is a microtubule-associated protein kinase, bovine brain tubulin was chromatographed on FPLC Mono Q and phosphocellulose columns. Several tubulin casein kinase (TCK) activities were apparent. All TCK activities phosphorylated tubulin and casein, but none was able to phosphorylate the CKII-specific synthetic peptide RRREEETEEE. One of these TCK fractions was immunoreactive to the antibody directed against CKII, and this antibody labeled a 50-kDa molecular mass band that had a molecular mass distinctly different from those of the subunits of CKII. Thus, we suggest that a CKII-like protein, but not CKII, might be a microtubule-associated protein.


Ferric iron reduction and iron assimilation in Saccharomyces cerevisiae. We have used the yeast Saccharomyces cerevisiae as a model organism to study the role of ferric iron reduction in eucaryotic iron uptake. S. cerevisiae is able to utilize ferric chelates as an iron source by reducing the ferric iron to the ferrous form, which is subsequently internalized by the cells. A gene (FRE1) was identified which encodes a protein required for both ferric iron reduction and efficient ferric iron assimilation, thus linking these two activities. The predicted FRE1 protein appears to be a membrane protein and shows homology to the beta-subunit of the human respiratory burst oxidase. These data suggest that FRE1 is a structural component of the ferric reductase. Subcellular fractionation studies showed that the ferric reductase activity of isolated plasma membranes did not reflect the activity of the intact cells, implying that cellular integrity was necessary for function of the major S. cerevisiae ferric reductase. An NADPH-dependent plasma membrane ferric reductase was partially purified from plasma membranes. Preliminary evidence suggests that the cell surface ferric reductase may, in addition to mediating cellular iron uptake, help modulate the intracellular redox potential of the yeast cell.


Inhibition of phosphorylation of synapsin I and other synaptosomal proteins by beta-bungarotoxin, a phospholipase A2 neurotoxin. Some snake venom neurotoxins, such as beta-bungarotoxin (beta-BuTX), which possess relatively low phospholipase A2 (PLA2) activity, act presynaptically to alter acetylcholine (ACh) release both in the periphery and in the CNS. In investigating the mechanism of this action, we found that beta-BuTX (5 and 15 nM) inhibited phosphorylation, in both resting and depolarized synaptosomes, of a wide range of proteins, including synapsin I. Naja naja atra PLA2, which has higher PLA2 activity, also inhibited phosphorylation but was less potent than beta-BuTX. At 1 nM, beta-BuTX and N. n. atra PLA2 inhibited phosphorylation of synapsin I only in depolarized synaptosomes. Synaptosomal ATP levels were not affected by 5 or 15 nM beta-BuTX or by 5 nM N. n. atra PLA2. Limited proteolysis, using Staphylococcus aureus V-8 protease, indicated that beta-BuTX inhibited phosphorylation of synapsin I in both the head and the tail regions. The inhibition of phosphorylation was not antagonized by nordihydroguaiaretic acid or indomethacin, suggesting that arachidonic acid derivatives do not mediate this inhibition. Furthermore, inhibition of phosphorylation by beta-BuTX and N. n. atra PLA2 was not altered in the presence of the phosphatase inhibitor okadaic acid, suggesting that stimulation of phosphatase activity is not responsible for this inhibition. Inhibition of protein phosphorylation by PLA2 neurotoxins and enzymes may be associated with an inhibition of ACh release.


Relationship between platelet monoamine oxidase B activity and alleles at the MAOB locus. Genetic variations in monoamine oxidase (MAO)-B activity have been proposed to have a contributory role in several neurologic and psychiatric diseases. Variations in activity could affect rates of degradation of exogenous amines, including toxins, precursors of toxins (like 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), or false transmitters, and of endogenous amines, such as neurotransmitters. In this study a highly polymorphic (GT)n repeat element was used to mark alleles at the MAOB locus. The MAOB allele status and levels of platelet MAO-B activity were determined for 41 control males. No correlation was noted between specific alleles and levels of MAO-B activity in this sample set. This suggests that the structural gene for MAOB is not usually the primary determinant of activity levels in platelets.


Nicotinylalanine increases the formation of kynurenic acid in the brain and antagonizes convulsions. Kynurenic acid (KYNA) was quantified in the extracellular spaces of the rat hippocampus using microdialysis and HPLC (fluorimetric detection) to study the possible role of this tryptophan metabolite in the modulation of the function of the N-methyl-D-aspartate (NMDA) receptor. Addition of probenecid (1 mM), which is an inhibitor of the organic acid transport system, to the Ringer's solution perfusing the dialysis probe increased the KYNA concentration in the dialysate from 10.4 +/- 0.9 to 48 +/- 6 nM. Addition of 2 mM aminooxyacetic acid, a nonspecific inhibitor of KYNA synthesis, reduced this concentration by 50%. These data suggest that KYNA is continuously synthesized in the rat hippocampus. Nicotinylalanine (NAL), 200-400 mg/kg i.p., an analogue of kynurenine that is able to direct the flow of tryptophan metabolites toward the synthesis of KYNA, significantly increased the KYNA concentration in the hippocampal dialysate and significantly potentiated the effect of tryptophan on the accumulation of KYNA in the brain and other organs. This increase resulted in pharmacological actions compatible with an antagonism of the NMDA receptors. In fact, NAL antagonized sound-induced seizures and prevented death in DBA/2 mice. Pretreatment of the mice with D-serine (100 micrograms intracerebroventricularly), a glycine agonist and a competitive antagonist of KYNA, completely prevented the anticonvulsive action of NAL. These data suggest that changes in the extracellular concentration of KYNA in the brain are associated with a modulation of NMDA receptor function.


Stimulation of phosphatidylinositol hydrolysis by brain-derived neurotrophic factor and neurotrophin-3 in rat cerebral cortical neurons developing in culture. Phosphatidylinositol (PI) breakdown represents a powerful system participating in the transduction mechanism of some neurotransmitters and growth factors and producing two second messengers, diacylglycerol and inositol trisphosphate. The transformation of PC12 neuroblastoma cells into neuron-like cells induced by nerve growth factor (NGF) is preceded by a rapid stimulation of PI breakdown; however, it was not known whether PI breakdown mediates actions of other members of the neurotrophin family. The present study analyzed the effects of NGF, brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) on PI breakdown in primary cultures of embryonic rat brain cells. Cultures were grown for 7 days; PI was then labeled by incubating cultures with myo-[3H]inositol, which then were exposed acutely to growth factors. BDNF and NT-3, but not NGF, elevated the levels of labeled inositol phosphates within 10-15 min after addition to the cultures in a dose-dependent manner. ED50 values for BDNF and NT-3 were 12.4 and 64.5 ng/ml, respectively. Comparable effects were found in cultures of cortical, striatal, and septal cells. The actions of BDNF and NT-3 probably reflect actions on neurons, because no effects were seen in cultures of nonneuronal cells. In contrast, basic fibroblast growth factor induced a marked stimulation of PI breakdown in cultures of nonneuronal cells. K252b, which selectively blocks neurotrophin actions by inhibiting trk-type receptor proteins, prevented the PI breakdown mediated by BDNF and NT-3. The findings suggest that rapid and specific induction of PI breakdown is involved in the signal transduction of BDNF and NT-3, and they provide evidence that cortical neurons are functionally responsive to BDNF and NT-3 during development.


Nicotinic agonists, phorbol esters, and growth factors activate two extracellular signal-regulated kinases, ERK1 and ERK2, in bovine chromaffin cells. Treatment of bovine chromaffin cells with nicotinic agonists, phorbol esters, and growth factors increases protein kinase activity toward microtubule-associated protein-2 and myelin basic protein (MBP) in vitro. To characterize the kinases that are activated by these agents, we separated chromaffin cell proteins by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels into which MBP had been incorporated, allowed the proteins to renature, and then assayed MBP kinase activity by incubating the gels with [gamma-32P]ATP. Chromaffin cells contain a family of kinases that phosphorylate MBP in vitro. Two of these kinases, of M(r) 46,000 and 42,000 (PK46 and PK42), were activated by treatment of the cells with dimethylphenylpiperazinium (DMPP), phorbol 12,13-dibutyrate (PDBu), or insulin-like growth factor I (IGF-I). Activation of PK46 and PK42 by DMPP was dependent on extracellular Ca2+, whereas the effects of PDBu and IGF-I were Ca2+ independent. Down-regulation of protein kinase C by incubation of the cells with PDBu abolished the activation of PK46 and PK42 by DMPP, PDBu, and IGF-I. Staurosporine, a protein kinase C inhibitor, prevented the activation of PK46 and PK42 by DMPP and PDBu but did not block the activation of these kinases by IGF-I. Immunoblotting experiments with antiphosphotyrosine (anti-PTyr) antibodies demonstrated that agents that increased the kinase activities of PK46 and PK42 also increased the apparent PTyr content of M(r) 46,000 and 42,000 proteins. PK46 and PK42 comigrated with proteins that reacted with antibodies against extracellular signal-regulated kinases (ERKs). Thus, PK46 and PK42 appear to be the bovine homologues of ERK1 and ERK2.(ABSTRACT TRUNCATED AT 250 WORDS)


Extracellular brain glucose levels reflect local neuronal activity: a microdialysis study in awake, freely moving rats. The relationship between brain extracellular glucose levels and neuronal activity was evaluated using microdialysis in awake, freely moving rats. The sodium channel blocker tetrodotoxin and the depolarizing agent veratridine were administered through the dialysis probe to provoke local changes in neuronal activity. The extracellular glucose content was significantly increased in the presence of tetrodotoxin and decreased sharply following veratridine application. The systemic injection of a general anaesthetic, chloral hydrate, led to a large and prolonged increase in extracellular glucose levels. The brain extracellular glucose concentration was estimated by comparing dialysate glucose efflux over a range of inlet glucose concentrations. A mean value of 0.47 mM was obtained in five animals. The results are discussed in terms of the coupling between brain glucose supply and metabolism. The changes observed in extracellular glucose levels under various conditions suggest that supply and utilization may be less tightly linked in the awake rat than has previously been postulated.


Recovery of cholinergic phenotype in the injured rat neostriatum: roles for endogenous and exogenous nerve growth factor. Polyclonal antibodies against recombinant human nerve growth factor (rhNGF) potently inhibited PC12 neurite outgrowth, blocked high-affinity 125I-rhNGF binding but not its receptor, and cross-reacted with rat, mouse, and human nerve growth factor (NGF) but not with brain-derived neurotrophic factor, neurotrophin-3, ciliary neurotrophic factor, insulin-like growth factor, epidermal growth factor, or activin A. Immunocytochemistry revealed many NGF-positive neurons in the rat neostriatum. The NGF-positive neurons disappeared by 3 days after mechanical injury to the neostriatum and were replaced by intensely NGF- and glial fibrillary acidic protein-positive astrocytes. Enzyme-linked immunosorbent assay measurements revealed that the NGF content of the injured striatum was elevated by eightfold 3 days postinjury and by twofold 2 weeks later. The high-affinity choline uptake (HACU) into cholinergic nerve terminals was decreased by 23% at 2 and 4 weeks postinjury, yet choline acetyltransferase (ChAT) activity in these neurons was unchanged at 2 weeks and decreased by 14% at 4 weeks. Daily infusion of 1 microgram of rhNGF into the injury area did not alter the loss of HACU. However, this treatment elevated ChAT activity by 23-29% above intact neostriatal levels and by 53-65% relative to HACU at both survival times. Thus, lesion-induced increases in NGF levels within astrocytes are associated with maintenance of striatal ChAT activity at normal levels following cholinergic injury, even with decreases in HACU. Pharmacologic doses of rhNGF can further augment ChAT activity in damaged cholinergic neurons, showing the usefulness of exogenous NGF even when endogenous NGF is elevated in response to injury.


Ethanol and excitotoxicity in cultured cortical neurons: differential sensitivity of N-methyl-D-aspartate and sodium nitroprusside toxicity. Neural injury due to ischemia and related insults is thought to involve the action of excitatory amino acids at N-methyl-D-aspartate receptors, which results in the influx of extracellular Ca2+ and the generation of nitric oxide. Because ethanol inhibits physiologic responses to excitatory amino acids, we examined its effect on toxicity induced by N-methyl-D-aspartate and by the nitric oxide donor sodium nitroprusside in neuron-enriched cultures prepared from rat cerebral cortex. Both N-methyl-D-aspartate and sodium nitroprusside were cytotoxic, as measured by the release of lactate dehydrogenase and by microfluorescent determination of cell viability. Ethanol (3-1,000 mM) protected cultures from N-methyl-D-aspartate but not sodium nitroprusside toxicity, and the ability of a series of n-alkanols to reproduce the effect of ethanol was related to carbon-chain length. Neuroprotection by ethanol was accompanied by a decrease in the N-methyl-D-aspartate-evoked elevation of free intracellular Ca2+ and did not appear to involve gamma-aminobutyric acid- or cyclic GMP-mediated mechanisms. These findings suggest that ethanol inhibits excitotoxicity at an early step in the N-methyl-D-aspartate signaling pathway, probably by reducing Ca2+ influx, and not by interfering with the action of nitric oxide.


Carboxypeptidase M in brain and peripheral nerves. Carboxypeptidase M (CPM), a plasma membrane-bound enzyme, cleaves C-terminal basic amino acids with a neutral pH optimum. We studied its distribution in human, baboon, and dog brain and in dog peripheral nerves. Areas were dissected, homogenized, centrifuged, and assayed for activity with dansyl-Ala-Arg. The corpus callosum and the pyramidal and optic tract were especially rich in CPM, whereas basal ganglia and cortex had low activity. The identity of the basic carboxypeptidase activity with CPM was shown by similarities in subcellular localization, membrane attachment, substrate hydrolysis, inhibition by a specific basic carboxypeptidase inhibitor, and cross-reaction with anti-human CPM antiserum. This antiserum immunoprecipitated an average of 85% of the activity in human and baboon brain and approximately 66% in dog brain. CPM co-purified with myelin extracted from the brain. Consistent with results obtained in placenta and cultured kidney cells, CPM in the brain appears to be membrane-bound via a phosphatidylinositol glycan anchor. In the peripheral nerves, the specific activity in dog sciatic nerve and in vagus was high (98 and 149 nmol/h/mg of protein, respectively). In immunohistochemical studies, glia in the brain, which appear to be oligodendrocytes or astrocytes, and the outer aspects of myelin sheaths and Schwann cells in sciatic and vagus nerves were stained. We conclude that in some areas of the CNS and the PNS, CPM is closely associated with myelin and myelin-forming cells. Northern blot analysis revealed the presence of mRNA coding for CPM in the brain, showing that the enzyme is indeed synthesized there.


Role of thapsigargin-sensitive intracellular Ca2+ pools in secretion induced by muscarinic agonists in porcine adrenal chromaffin cells. The role of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]-sensitive Ca2+ pools in secretion, induced by muscarinic agonists in porcine adrenal chromaffin cells, was studied. Activation of muscarinic receptors, as in other species, was found to increase inositol phosphate production including that of Ins(1,4,5)P3. Treatment of cells with thapsigargin, which is known to deplete Ins(1,4,5)P3-sensitive Ca2+ pools, eliminated the initial transient component of increases in the cytosolic free Ca2+ concentration ([Ca2+]in) induced by the muscarinic agonist, methacholine, in both the presence and the absence of extracellular Ca2+. Thapsigargin treatment also decreased methacholine-induced secretion by about 30% in the presence of extracellular Ca2+ and essentially eliminated secretion that occurred independently of extracellular Ca2+ (which was about 30% of the secretory response that occurred in the presence of extracellular Ca2+). Thapsigargin itself had no effect on inositol phosphate production. These results indicate that about 30% of muscarinic agonist-induced secretion is mediated by the release of Ca2+ from Ins(1,4,5)P3- and thapsigargin-sensitive intracellular Ca2+ pools. These results also suggest that Ca2+ influx activated by muscarinic agonists is not due to depletion of intracellular Ca2+ pools, as prior depletion of these pools had no effect on the portion of the methacholine-induced secretory response and [Ca2+]in signal that was dependent on extracellular Ca2+.


Extracellular striatal concentrations of endogenous 3,4-dihydroxyphenylalanine in the absence of a decarboxylase inhibitor: a dynamic index of dopamine synthesis in vivo. Basal levels of endogenous 3,4-dihydroxyphenylalanine (DOPA) were detected by HPLC coupled with coulometric detection in dialysates from freely moving rats implanted 48-72 h earlier with transversal dialysis fibers in the dorsal caudate. Because decarboxylase inhibitor is absent in the Ringer's solution, this method allows monitoring of basal output of dopamine (DA) and 3,4-dihydroxyphenylacetic acid, as well as DOPA. Extracellular DOPA concentrations were reduced by the tyrosine hydroxylase inhibitor alpha-methylparatyrosine (200 mg/kg, i.p.) and by the dopaminergic agonist apomorphine (0.25 mg/kg, s.c.). The dopaminergic antagonist haloperidol (0.2 mg/kg, s.c.) stimulated DOPA output by about 60% over basal values. Gamma-Butyrolactone, at doses of 700 mg/kg, i.p., which are known to block dopaminergic neuronal firing and which reduce DA release, stimulated DOPA output maximally by 130% over basal values. Tetrodotoxin, which blocks DA release by blocking voltage-dependent Na+ channels, increased DOPA output maximally by 100% over basal values. The results indicate that basal DOPA can be detected and monitored in the extracellular fluid of the caudate of freely moving rats by transcerebral dialysis and can be taken as a dynamic index of DA synthesis in pharmacological conditions.


Effects of electroconvulsive shock on tetrahydrobiopterin and GTP-cyclohydrolase activity in the brain and adrenal gland of the rat. The effects of a single and repeated electroconvulsive shock (ECS) (300 mA, 0.2 s) on tetrahydrobiopterin (BH4) levels and GTP-cyclohydrolase activity in the brain and adrenal glands of rats were examined. Twenty-four hours after the last ECS treatment (one/day for 7 days), biopterin levels were significantly elevated in the locus coeruleus, hippocampus, frontal cortex, hypothalamus, ventral tegmental area, and adrenal gland. There were no changes in biopterin levels after a single application of ECS. GTP-cyclohydrolase activity was significantly increased in the locus coeruleus, frontal cortex, hippocampus, hypothalamus, and adrenal gland 24 h after repeated ECS and remained elevated in certain tissues up to 8 days after the last treatment. Kinetic analysis of adrenal and locus coeruleus GTP-cyclohydrolase 1 day after 7 days of ECS showed significant changes in both Km and Vmax values. These data suggest that the long-term increases in BH4 levels and GTP-cyclohydrolase activity after repeated ECS may play a part in the mediation of the antidepressant effects of ECS.


Muscarinic acetylcholine receptor enhances phosphatidylcholine hydrolysis via phospholipase D in bovine chromaffin cells in culture. Although it is well-established that inositol-containing lipids serve as precursors of intracellular second messenger molecules in chromaffin cells, we describe some findings that show the formation of diacylglycerol from phosphatidylcholine in response to agonist-mediated stimulation. Stimulation of chromaffin cells by acetylcholine produced a high turnover of phosphatidylcholine, as suggested by the release of [3H]choline derived from [3H]-phosphatidylcholine in experiments performed with [3H]choline chloride-prelabeled cells. An enhanced breakdown of phosphatidylcholine was also inferred from the finding of an increased formation of [3H]diacylglycerol in chromaffin cells prelabeled with [3H]glycerol. The diacylglycerol mass that accumulated after stimulation showed a distinct temporal course and seemed to exceed the mass that has been reported to be derived from phosphatidylinositol. In keeping with the purported origin from phosphatidylcholine, diacylglycerol showed a high content in [3H]oleate molecular species. Phospholipase D activity measurements and experiments performed in the presence of propranolol (an inhibitor of phosphatidic acid:phosphohydrolase) suggested that phosphatidylcholine is hydrolyzed by a phospholipase D activity, producing phosphatidic acid, which is subsequently degraded to diacylglycerol, rather than by a phospholipase C. Incubation of chromaffin cells in the presence of atropine before addition of acetylcholine showed complete inhibition of the increased formation of [3H]-diacylglycerol, whereas d-tubocurarine failed to do so. Taken together, these results suggest that acetylcholine activates phosphatidylcholine breakdown and diacylglycerol formation in chromaffin cells via a muscarinic-type receptor.


Regulation of carboxypeptidase E by membrane depolarization in PC12 pheochromocytoma cells: comparison with mRNAs encoding other peptide- and catecholamine-biosynthetic enzymes. PC12 cells, a rat pheochromocytoma cell line, have been found to express carboxypeptidase E (CPE) enzymatic activity and CPE, furin, and peptidylglycine alpha-amidating monooxygenase (PAM) mRNAs. PC12 cells secrete CPE activity in response to depolarization induced by 50 mM KCl. Short-term (1- to 3-h) treatments of PC12 cells with KCl stimulates the secretion of CPE but does not appear to stimulate the synthesis of new CPE protein, based on the measurement of CPE activity and incorporation of [35S]-Met into CPE. Also, CPE mRNA is not altered by 2-h treatments with KCl. In contrast, prolonged treatment (24-48 h) of PC12 cells with 50 mM KCl continues to stimulate the secretion of CPE activity, without altering the cellular level of CPE. Levels of CPE mRNA are significantly elevated after long-term treatment of the cells with KCl, with increases of 35% after 5 h and 55-75% after 24 to 72 h of treatment. The level of PAM mRNA is also elevated approximately 70% after 24 h of stimulation with KCl. In contrast, the mRNA levels of furin and dopamine beta-hydroxylase (DBH) do not change on treatment of PC12 cells with KCl. These findings indicate that long-term depolarization, which leads to a prolonged stimulation of PC12 cells to secrete CPE, also stimulates the synthesis of CPE and PAM but not furin or DBH.


Possible regulation of caffeine-induced intracellular Ca2+ mobilization by intracellular free Na+. To gain some understanding of the regulatory mechanism involved in caffeine-induced Ca2+ release in adrenal chromaffin cells, we took advantage of the paradoxical observation that removal of divalent cations potentiated the secretory response to caffeine. We measured the concentration of cytosolic free Ca2+ ([Ca]in) in isolated cat chromaffin cells, by fura-2 microfluorometry, to see whether there was any correlation between the secretory response and the rise in [Ca]in. The caffeine-induced [Ca]in rise and catecholamine secretion were increased by treatment of cells with a divalent cation-deficient solution. These potentiated responses were strongly inhibited either by pretreatment with ryanodine, by the reduction of the external Na+ concentration, or by the addition of Ca2+ channel blockers. Removal of divalent cations caused a large rise in the cytosolic free Na+ concentration ([Na]in), which was measured using SBFI microfluorometry. This rise in [Na]in was reduced either by adding Ca2+ channel blockers or by reducing the external Na+ concentration. These results show a good correlation between caffeine-induced Ca2+ release and [Na]in at the time of stimulation, suggesting that caffeine-induced Ca2+ release is regulated by [Na]in.


Alteration of neuroblastoma ganglioside metabolism by retinoic acid. Cellular differentiation is often associated with striking changes in ganglioside metabolism. Because retinoic acid causes cellular differentiation in vitro, we have characterized its effect on ganglioside synthesis and shedding by LAN-5 human neuroblastoma cells. Three major observations were made: (a) 20 microM retinoic acid caused a marked (twofold) increase in cellular ganglioside content, with a slight relative enhancement in GD1a and GT1b synthesis, (b) ganglioside shedding increased in parallel with increased cellular ganglioside content, and also, unexpectedly, (c) retinoic acid caused a quantitatively similar increase in content of cell membrane phospholipids, which are also shed. We conclude that enhanced ganglioside synthesis and shedding by retinoic acid are part of a previously undescribed generalized stimulatory effect on membrane lipid metabolism.


Specific irreversible monoamine oxidase B inhibitors stimulate gene expression of aromatic L-amino acid decarboxylase in PC12 cells. The effect of some selective monoamine oxidase (MAO) inhibitors on aromatic L-amino acid decarboxylase (AADC) gene expression in PC12 cells has been examined. Irreversible MAO B inhibitors [(-)-deprenyl, pargyline, and MDL 72,974A] stimulated AADC gene expression, whereas a selective irreversible MAO A inhibitor (clorgyline) and a reversible MAO B inhibitor (Ro 19-6327) had no effect. Because there is no apparent MAO B activity in PC12 cells, it is postulated that there is a novel site of action for these MAO B inhibitors and that the pharmacological profile of this site matches that of neuroprotective MAO B inhibitors. Finally, it is suggested that the stimulation of AADC gene expression may be relevant to the antiparkinsonian effects of MAO B inhibitors.


An alternative secretase cleavage produces soluble Alzheimer amyloid precursor protein containing a potentially amyloidogenic sequence. Cell culture studies have shown that the Alzheimer amyloid precursor protein (APP) is secreted after full-length APP is cleaved by a putative secretase at the Lys16-Leu17 bond (secretase cleavage I) of the amyloid peptide sequence. Because this cleavage event is incompatible with amyloid production, it has been assumed that secreted APP cannot serve as a precursor of the amyloid depositions observed in Alzheimer's disease. Here we show that in neuronally differentiated PC12 cells and human kidney 293 cell cultures a portion of the secreted extracytoplasmic APP reacted specifically with both a monoclonal antibody recognizing amyloid protein residues Leu17-Val24 and a polyclonal antiserum directed against amyloid protein residues Ala21-Lys28. Furthermore, this APP failed to react with antisera recognizing the cytoplasmic domain of the full-length protein. These data indicate the presence of an alternative APP secretase cleavage site (secretase cleavage II), C-terminal to the predominant secretase cleavage I. Depending on the exact location of cleavage site II, potentially amyloidogenic secreted APP species may be produced.


Lithium enhances accumulation of [3H]inositol radioactivity and mass of second messenger inositol 1,4,5-trisphosphate in monkey cerebral cortex slices. We previously reported that lithium, in the presence of acetylcholine, increased accumulations of inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate in brain cortex slices from the guinea pig, rabbit, rat, and mouse. In the mouse and rat, the Li(+)-induced increases required supplementation of the medium with inositol. This probably relates to the following facts: (a) Brain cortices of the mouse and rat contain in vivo concentrations of inositol half of that of the guinea pig. (b) Incubated rat brain cortex slices are depleted of inositol by 80%. (c) The slices require 10 mM inositol supplementation to restore in vivo concentrations. We now show that in monkey brain cortex slices, therapeutic concentrations of Li+ increase accumulation of inositol 1,4,5-trisphosphate. The inositol 1,3,4,5-tetrakisphosphate level is not increased. Neither inositol nor an agonist is required. The same effects are seen whether inositol 1,4,5-trisphosphate is quantified by the [3H]inositol prelabeling technique or by mass assay, although mass includes a pool of inositol 1,4,5-trisphosphate that is metabolically inactive. Thus, in a therapeutically relevant model for humans, Li+ increases inositol 1,4,5-trisphosphate levels in brain cortex slices, as was previously seen in lower mammals at non-rate-limiting concentrations of inositol.


Metabotropic excitatory amino acid receptor activation stimulates phospholipase D in hippocampal slices. Metabotropic excitatory amino acid (EAA) receptors are coupled to effector systems through G proteins. Because various G protein-coupled receptors stimulate the hydrolysis of phosphatidylcholine by phospholipase D (PLD), we examined the possibility that metabotropic EAA receptors exist that are coupled to the activation of PLD. We found that the selective metabotropic glutamate receptor (mGluR) agonists 1S,3R-amino-1,3-cyclopentanedicarboxylic acid (ACPD) and 1S,3S-ACPD, but not the inactive isomer, 1R,3S-ACPD, induce a concentration-dependent increase in PLD activity in hippocampal slices. Selective ionotropic glutamate receptor (iGluR) antagonists did not block 1S,3R-ACPD-induced PLD stimulation. Furthermore, although selective iGluR agonists did not activate this response, the nonselective mGluR-iGluR agonists, ibotenate and quisqualate, caused significant increases in PLD activity (all in the presence of iGluR antagonists). L-2-Amino-3-phosphonopropionic acid, which blocks the mGluR that is coupled to phosphoinositide hydrolysis in various brain regions, activates PLD to the same extent as the active isomers of ACPD. These data suggest that metabotropic EAA receptors exist in hippocampus that are coupled to PLD activation and are pharmacologically distinct from phosphoinositide hydrolysis-coupled mGluRs.


Factors influencing survivorship of the femoral component after primary low-friction hip arthroplasty. Two hundred sixty-seven consecutive primary low-friction arthroplasties, followed for 5-18 years after surgery, were studied to assess the factors influencing survivorship of the femoral component, using the Kaplan-Meier method. The end point of survivorship was defined radiographically in two ways: incipient failure (subsidence of the femoral component of > or = 2 mm) and definite failure (progressive change of position). Twenty-two femoral components developed incipient failure, and twelve of these advanced to definite failure. A canal filling ratio of the stem of > or = 75%, cement extent distal to the stem tip of > or = 1 cm, use of an intramedullary bone plug, and an exaggerated valgus alignment of the stem correlated positively with survivorship of the femoral component. Calcar resorption and atrophy of the femoral cortex after surgery were associated with aseptic loosening of the femoral component.


Total hip arthroplasty in active golfers. Total hip arthroplasty (THA) is commonly performed in an older population, for whom gold is often the only form of exercise. Members of the Hip Society do not feel that golfers have increased rates of complications after THA when compared to nongolfers and permit their patients to play gold with a THA. Most golfers will see their handicaps increase after total joint arthroplasty, although this does not appear to be a function of drive length. Most golfers with a successful primary total joint arthroplasty will not have pain while playing golf but will likely experience a mild ache in the hip region after playing. Hybrid and uncemented primary THAs appear to have lower rates of radiographic loosening in active golfers when compared to cemented THAs. However, symptoms of pain while playing or after playing do not differ among these groups, despite this radiographic difference.


Survivorship of cemented total hip arthroplasty in patients 50 years of age or younger. One hundred fifty-six Charnley low-friction arthroplasties performed in patients 50 years of age or younger are reviewed. Excluding sepsis, survivorship analysis showed a 12% probability of mechanical failure at 10 years. The detailed clinical and radiological results of 130 hips with a 3-16-year follow-up period are presented. Revision surgery was required in 14 hips (10.8%), for the following reasons: sepsis (2.3%), loose sockets (2.3%), loose stems (5.4%), and stem fracture (0.8%). Evidence of radiological loosening indicative of pending failure was present in 14 hips (12.0%). At 10 years the predicted failure rate of the surviving hips was 12%.


Clinical and radiographic analysis of the uncemented LSF total hip arthroplasty. Forty-nine consecutive uncemented porous-coated LSF total hip prostheses were implanted in 41 patients and studied prospectively. Clinical rating as described by Harris was performed preoperatively, at 6 months and 1 year postoperatively, and annually thereafter. Anteroposterior and lateral radiographs were obtained preoperatively, immediately postoperatively, at 6 and 12 months, and annually thereafter. At the most recent follow-up visit, patients were evaluated clinically and radiographically utilizing the format recently recommended by the Hip Society. A patient satisfaction questionnaire was also completed. The follow-up period averaged 37 months (range, 24-48 months). Preoperative hip scores averaged 38 (range, 18-68) and improved to 93 at the most recent follow-up visit (range, 76-100). The incidence of mild pain was 14% at 1 year and 4% at 2 years or more. The incidence of limp was 16% slight and 8% moderate at 1 year, and 12% slight and 2% moderate at 2 years or more. Surgical fit was objectively graded as excellent in 61%, good in 33%, and poor in 6%. The authors were unable to correlate surgical fit with clinical scores or radiographic findings. According to radiographic criteria, all components were judged to be stable and 86% were judged to demonstrate objective signs of osseointegration. Patient satisfaction with the procedure was 100%. All patients stated that the procedure increased their function and decreased their pain and need for medication. Compared to a normal hip, in terms of symptoms and function, the patients rated their postoperative hip at 85% (range, 50-100%). Compared to their level of activity before their hip was symptomatic, they rated their current activity level as 83% (range, 50-100%).


Influential factors in cemented acetabular cup loosening. To delineate further the cause of acetabular loosening in a group of 238 total hip arthroplasties performed between 1980 and 1982, the authors subjected those total hip arthroplasties to a multifactorial analysis utilizing the log normal model. Data collected on each patient consisted of age, sex, weight at the time of surgery, diagnosis, cement thickness between zones 1 and 2 and between zones 2 and 3, polyethylene thickness, lateral tilt, and metal backing of the acetabular components. The acetabulum was considered a failure by radiographic loosening with migration greater than 5 mm, revision in patients younger than 60 years of age (P = 0.154), or when the acetabular cup was metal-backed (P = .001).


Cementless hip arthroplasty in diastrophic dysplasia. Diastrophic dysplasia results in severe disproportionate growth failure, generalized joint dysplasia, and early osteoarthrosis of the hips. A total hip arthroplasty is often necessary in patients afflicted with diastrophic dysplasia by time they reach early middle age. During 1983-1988, total hip arthroplasties were performed on six women and four men (15 hips) with diastrophic dysplasia at the Orthopaedic Hospital of the Invalid Foundation. The mean age of the patients at the time of operation was 37 years and the mean height was 133 cm. A Lord endoprosthesis was used in nine hips and a Biomet endoprosthesis in six. Cementless fixation was used in all cases. Autogenous bone grafting to the acetabulum was performed in six hips. Simultaneous corrective osteotomy of the proximal femur and transposition of the greater trochanter was performed in three cases. Soft tissue release and tenotomies were performed in 10 hips. The average follow-up period was 5 years. Overall clinical results were good, with marked relief of pain and improvement of hip joint mobility. Aseptic loosening of the acetabular component was noted in two hips. As for complications, two femoral nerve paresis and two perioperative fractures of the proximal femur occurred, which all healed.


Measurement of acetabular component migration using two-dimensional radiography. The relationships between apparent acetabular component migration, choice of anatomic landmarks, and changes in rotation of the pelvis were determined by examining radiographs of a pelvic model in multiple projections. The minimum apparent migration associated with transverse and longitudinal rotation of 5 degrees from neutral was 2 mm. The least apparent migration was noted when the teardrop was used as the principal anatomic landmark. Determination of component migration in clinical studies from serial radiographs involves a minimum projection and magnification error of 2 mm.


Cementless total hip arthroplasty using a porous-coated prosthesis for bone ingrowth fixation. 3 1/2-year follow-up. The clinical and radiologic results of a consecutive series of 59 patients (69 hips) who had primary total hip arthroplasty using cementless prostheses was studied. Harris-Galante acetabular and femoral prostheses, which have a porous fiber-metal mesh coating intended to encourage bone ingrowth fixation, were used in all cases. Two femoral components were revised during the follow-up period, one for aseptic loosening and the other for late septic loosening. In the remaining 67 hips, the average Harris hip score rose from a preoperative 52 to 94 at the last follow-up examination (average follow-up period, 44 months). Eighty-eight percent of these hips had an excellent result (Harris hip score of 90 or more). Radiologic analysis demonstrated that all the acetabular components were stable. Eighty-three percent of the femoral components appeared to have stable bone ingrowth fixation, five components (7%) had stable fibrous ingrowth, and seven (10%) were unstable. Parallel radiodense lines were seen around the smooth portion of the stem in 93% of hips, but this finding appeared to have no clinical importance. Significant stress shielding of the proximal femur was seen in 16% of hips. Endosteal lysis of the distal femur occurred in 22% of hips, including large lesions in two patients who will require future revision surgery because of femoral diaphysis weakening. Femoral lysis was not associated with hip or thigh pain and was most common in young, male patients who had high activity levels.(ABSTRACT TRUNCATED AT 250 WORDS)


In vitro study of initial stability of a conical collared femoral component. This in vitro experimental study compared the initial stability of an uncemented conical collared femoral component to that of the same component with the collar removed. The two configurations examined simulated joint resultant forces encountered in single leg stance and stair climbing. For the simulated single leg stance loads, the data do not allow any inferences about relative component stability. With the exception of one collarless control, all micromotion for single leg stance loading was under 150 microns, measured approximately 1.5 cm below the resection line. For scaled stair-climbing loads, however, the conical collared component group was significantly more stable than the collarless control group in transverse (primarily rotational) micromotion. The overall average measured transverse motion for the collarless control group was more than 3.7 times greater than that of the conical collar group at scaled stair-climbing loads. The two conical collared components loaded to full peak stair-climbing load (2,100 N) exhibited micromotion under 160 microns. The results suggest that the conical collar may improve stability of an uncemented prosthesis under loads that include an out-of-plane (rotational) component.


Use of an antibiotic impregnated polymethyl methacrylate intramedullary spacer for complicated revision total hip arthroplasty. Revision total hip arthroplasty is frequently necessary in the presence of significant proximal femoral bone loss, periprosthetic fracture, or infection. In these situations, optimal reconstruction may sometimes warrant the use of special implants, including bone grafts. The emergent presentation of these cases or unexpected findings at the time of surgery can preclude the use of these treatment options. In cases of periprosthetic sepsis, delayed reimplantation may be the most successful approach to eradicate infection. In seven of these complicated revision total hip arthroplasties, the authors used an antibiotic-impregnated intramedullary polymethyl methacrylate spacer with delayed prosthetic reimplantation to allow for the use of these methods. Benefits of this technique include uncompromised radiographic evaluation of the proximal femur for design of a custom implant, if needed, stabilization of the proximal femur facilitating early mobilization of the patient in the case of periprosthetic fracture, and local delivery of antibiotics to the wound in the case of infection. The author's ability to reconstruct these total hip arthroplasties complicated by bone deficiency, fracture, and sepsis, was significantly improved with this use of this technique.


Preoperative planning for total hip arthroplasty. Quantitating its utility and precision. This study evaluated the usefulness and accuracy of preoperative planning for cemented and cementless total hip arthroplasty (THA). The authors conducted a prospective study of 110 consecutive primary cases in which surgeons recorded the preoperative plan and what occurred in each case. Measured variables included estimated magnification, acetabular cup and femoral stem size, planned lengthening, and anticipated problems. Preoperative estimates of magnification frequently differed from actual magnification, and in 17% of cases it affected choice of implant size. Preoperative bone morphology did not correlate with type of femoral stem fixation. Implant sizing was predicted from the preoperative plan for 62% of acetabular cups, 78% of cemented stems, and 42% of the cementless stems. Leg-length equalization was a goal in only 70% of cases. Anticipated problems focused on anatomic variations, but intraoperative problems involved technique and equipment. The authors conclude that surgeons need better methods to estimate magnification and bone morphology from preoperative radiographs. Preoperative planning may not reduce intraoperative complications, which can arise from unanticipated technique and equipment mishaps.


A new femoral cement restrictor.

A new femoral cement restrictor. The authors report on the clinical trial of a new femoral cement restrictor for use during hip arthroplasty. Instrumentation and technique are described. The restrictor has three components made of high-density polyethylene that fit one inside the other and is available in small, medium, and large sizes. The advantages of this new restrictor are ease of use and secure fixation in the femoral canal when deployed. Because of its inherent strength and design, small particles do not break off during insertion. The apex of the restrictor points proximally and is cupped. This helps in centralizing the stem. It also assists in obtaining good cement pressurization as it does not distally migrate in the femoral canal when pressurization is attempted. Also, no cement escapes distally beyond it. Furthermore, should revision surgery be required, the restrictor can be easily removed without the need for windowing the femoral cortex.


Intramedullary plugs in total hip arthroplasty. A comparative study. The quality of cement packing was radiographically evaluated using three different types of intramedullary plugs in 77 total hip arthroplasties. The Thackray polyethylene plug (38 mm, disc-shaped), with its large and flexible diameter, was best able to seal the femoral canal and produced significantly better cement packing compared to both the autologous bone plug and the Richard polyethylene plug (18.5 mm, bullet-shaped).


Surgical management of gonarthrosis in patients with poliomyelitis. The authors reviewed nine cases of degenerative disease of the knee in patients with a history of poliomyelitis. All patients were treated with a cemented total knee arthroplasty. The average follow-up period was 6.8 years (range, 6 months to 13 years), and the average follow-up knee score using the Hospital for Special Surgery rating scale was 70. Three of the patients required revision total knee arthroplasty to a more constrained implant. Pain relief was predictably very good and knee stability was initially improved. However, many of the patients suffered a decline in ambulatory ability with time.


Lateral patellar release in knee arthroplasty. Effect on wound healing. A prospective study analyzing the effects of intraoperative lateral patellar release for patellar instability in total condylar knee arthroplasty demonstrated that lateral release was successful in preventing postoperative patellar instability. Division of the superolateral geniculate vessels resulted in an increased incidence of wound discoloration (P < .01) and superficial wound infection (P < .05). Perioperative transcutaneous measurement of the skin oxygen tension demonstrated an objective reduction in lateral wound edge skin viability following lateral release (P < .02). A lower threshold for performing lateral patellar release is necessary. To preserve the viability of the lateral skin edge, lateral release should be performed using the intracapsular approach with preservation of the superolateral geniculate vessels.


The effect of central stem and stem length on micromovement of the tibial tray. The effects of a central stem and its length on cementless tibial tray micromovement were investigated using preserved cadaver tibial specimens. For axial loading tests, cyclical compressive loads ranging 50-1000 N were applied to the anterolateral portion of the implanted tray. With subsidence on the loaded side and lift-off on the contralateral side, micromotions on both sides and bending of the tray were measured. The three groups consisted of a stemless group, a 7.5 cm (short) central stem group, and a 15 cm (long) central stem group. For shear loading tests, shear loads ranging 20-250 N were applied to the central portion of the posterior rim of the tray anteriorly for 1,000 cycles. Displacement values for subsidence and micromotion were measured on the medial and lateral side of the trays and compared for each group. For axial tests, the long stem minimized subsidence and lift-off (P < .05) when compared to the stemless group. Although the short stem also tended to prevent contralateral lift-off, no significant difference was shown when compared to the stemless group. However for shear loading, both central stem lengths significantly reduced subsidence and micromotion (P < .05). The authors conclude that the tibial tray with a long stem can achieve better initiation fixation of the implant to bone when compared to the short stem and no stem groups.


Severe metallosis due to abnormal abrasion of the femoral head in a dual bearing hip prosthesis. A case report. The authors report on a patient with a case of severe metallosis due to an abnormal abrasion of the femoral head. A primary arthroplasty was performed using a dual bearing hip prosthesis with acetabular bone grafting by ceramic screws. At the time of the revision surgery the synovia was black, and an analysis using a scanning electron microscope and scanning electron microscope-electron probe micro-analyzer revealed numerous small particles of small alumina ceramic on the inner surface of the bearing insert of high-density polyethylene. These particles, which came from the broken ceramic screws due to proximal migration of the prosthesis, scraped the femoral head away. A line and area analysis of the black synovia revealed that the synovia contained metal particles of a cobalt-chromium alloy as well as a cobalt ion. The patient's serum showed elevated concentrations of cobalt, chromium, and molybdenum that dramatically reduced 2 months after the revision surgery.


Ankle pain following total knee arthroplasty. A case report. The authors present their experience with four cases of ankle pain occurring in the immediate postoperative period after total knee arthroplasty. In a 40-month period, the authors performed 87 total knee arthroplasties. In the first 28 cases, an extramedullary alignment rod was used and there were no instances of ankle pain (0%). In the next 30 cases, an intramedullary alignment rod was employed and there were three cases of moderate to severe ankle pain (10%). In the last 29 cases, the medullary canal was decompressed, irrigated, and aspirated prior to insertion of the alignment rod. In this group there was only one case of mild ankle discomfort (3.5%). An extensive investigation was made into one of the cases in which the intramedullary alignment rod was used but the canal was not aspirated. Information from this case investigation, observation of the three subsequent cases, and the notation of a decrease in the incidence of ankle pain once aspiration was routinely used are reported. The unproven hypothesis that ankle pain may result from compression of the marrow contents into the bone interstices is presented for consideration. Three of the four cases of ankle pain reported here were spontaneously resolved within 9 months after surgery.


Late disassembly of a modular acetabular component. A case report. Disassembly of metal-backed acetabular components used for total hip arthroplasty is becoming more common in both preassembled and modular designs. This complication is usually associated with a dislocation of the femoral component or other radiographic evidence of dissociation. A case of late disassembly of the acetabular component without dislocation or radiographic evidence is presented. The authors believe this complication should be considered, along with infection and aseptic loosening, in all cases of late development of pain following total hip arthroplasty.


Antitumor agents, 129. Tannins and related compounds as selective cytotoxic agents. Fifty-seven tannins and related compounds, including gallotannins, ellagitannins, and condensed and complex tannins, were evaluated for their cytotoxicities against human tumor cell lines, including malignant melanoma, lung carcinoma, ileocecal adenocarcinoma, epidermoid carcinoma, malignant melanoma, and medulloblastoma cell lines. Among them, chebulagic acid [1], geraniin [2], sanguiin H-11 [3], 4,5-di-O-galloylquinic acid [12], 1,3,4,5-tetra-O-galloylquinic acid [15], 1(beta)-O-galloylpedunculagin [24], furosin [29], castalagin [38], sanguiin H-2 [34], vescalagin [39], grandinin [40], phyllyraeoidin A [42], (-)-epicatechin 3-O-gallate [50], cinnamtannin B2 [55], and acutissimin A [56] exhibited moderate selective cytotoxicity against PRMI-7951 melanoma cells with ED50 values in the range of 0.1-0.8 microgram/ml. Selective cytotoxicities against the melanoma cells were also observed for strictinin [22], pedunculagin [23], eugeniin [25], elaeocarpusin [28], punicacortein C [37], casuarinin [41], sanguiin H-6 [43], procyanidin B-2 3,3'-di-O-gallate [51], procyanidin C-1 3,3',3"-tri-O-gallate [52], and cinnamtannin B1 [54] with ED50 values of 1-4 micrograms/ml. All of the tannins were found to be inactive (greater than 10 micrograms/ml) against lung carcinoma (A-549), ileocecal adenocarcinoma (HCT-8), epidermoid carcinoma of nasopharnyx (KB), and medulloblastoma (TE-671) tumor cells.


A bioassay for inhibition of serotonin release from bovine platelets. A bioassay was developed to study agents capable of inhibiting the release of serotonin from bovine blood platelets. It is a simple, inexpensive, and reproducible high-throughput bioassay suitable for quality control of feverfew, Tanacetum parthenium, a crude drug with proven migraine prophylactic activity that is being considered for governmental registration and regulation. The bioassay, which requires no experimental animals or human subjects, was used to assess the in vitro activity of T. parthenium samples grown from seed obtained from 10 different regions of Europe. The activity was found to vary significantly within and between samples, with no geographical correlation. Serotonin release inhibition was shown to be significantly correlated with the content of the germacranolide sesquiterpene lactone, parthenolide, although other sesquiterpene lactones from this plant and other members of the Asteraceae were also shown to be active. The activities of six other species of Tanacetum, as well as of Artemisia absinthium (wormwood) and Zingiber officinale (ginger), and two commercial drugs for migraine prophylaxis, verapamil hydrochloride and propranolol hydrochloride, were also assessed. The relevance of the bovine platelet serotonin release inhibition bioassay to antimigraine research is discussed.


New bioactive metabolites from a freshwater isolate of the fungus Kirschsteiniothelia sp. The new cytotoxic naphthoquinone dimer kirschsteinin [5], two new chlorinated diphenyl ethers 8 and 9, three known naphthoquinone derivatives 1, 2, and 7, a monoacetyl derivative of 2, and the (-)-enantiomer of O-methylasparvenone [4], have been isolated from a previously undescribed species of Kirschsteiniothelia. The structures of these compounds were assigned primarily by nmr studies and by spectral comparisons.


Molluscicidal acridone alkaloids from Angostura paniculata: isolation, structures, and synthesis. Two novel acridone alkaloids, cuspanine [1] and cusculine [2], were isolated from the CH2Cl2 extract of the leaves of Angostura paniculata (Rutaceae). Their structures were established as 1-hydroxy-2,3,5,6-tetramethoxy-9-acridone for 1 and 1,2,3,5,6-pentamethoxy-9-acridone for 2 by means of spectroscopic studies, in particular nmr. These structural assignments were confirmed by synthesis, using a direct metallation method as a key reaction. Both alkaloids exhibited moderate molluscicidal activity against an aquatic snail, Biomphalaria glabrata, and cytotoxicity against several types of carcinoma cell lines.


(+)-4 beta-hydroxyhernandulcin, a new sweet sesquiterpene from the leaves and flowers of Lippia dulcis. From the leaves and flowers of Lippia dulcis collected in Panama, a new sweet sesquiterpene identified as (+)-4 beta-hydroxyhernandulcin [2] was isolated, accompanied by (+)-hernandulcin [1], (-)-epihernandulcin [3] (a novel natural product), and 6-methyl-5-hepten-2-one [4]. Acteoside (verbascoside) [5], a known bitter phenylpropanoid glycoside, was isolated from the flowers of L. dulcis. The structure of (+)-4 beta-hydroxyhernandulcin was established by interpretation of its spectral data.


Stereoselective synthesis and antimalarial activity of alpha-artelinic acid from artemisinin. alpha-Artelinic acid [8], a potent, stable, and water-soluble antimalarial agent, has been synthesized from artemisinin [1], the sesquiterpene lactone endoperoxide isolated from Artemisia annua. The blood schizontocidal antimalarial activity of alpha-artelinic acid evaluated against Plasmodium knowlesi is also reported.


Vasoconstrictor activity of 8-O-acetylharpagide from Ajuga reptans. The traditional therapeutic indications for the use of Ajuga reptans (Labiatae) have been investigated. The H2O-soluble part of a crude and partially purified MeOH extract and two isolated iridoids (8-O-acetylharpagide and harpagide), were tested for a biological activity on isolated smooth muscle preparations from guinea pig.


A new acylated N-glycosyl lactam from Aristolochia contorta. A new acylated glycoside isolated from the roots of Aristolochia contorta (Aristolochiaceae), has been characterized as aristolactam N-(6'-trans-p-coumaroyl)-beta-D-glucopyranoside [2]. Aristolactam-N-beta-D-glucopyanoside [1] was also isolated from the same source. Compound 2 showed relatively significant antibacterial activity against Gram-positive bacteria, based on disc diffusion and dilution methods.


Brominated polyacetylenic acids from the marine sponge Xestospongia muta: inhibitors of HIV protease. The EtOAc extract of the sponge Xestospongia muta collected in Colombus Island, Bahamas, yielded eleven straight-chain unsaturated, polyacetylenic, brominated acids, seven of which were identified on the basis of spectral data, including the unknown acids 2-7. These acetylenic acids are the first known examples that have been shown to inhibit HIV protease, a critical enzyme in the replication of human immunodeficiency virus.


The enzymatic decomposition of salicin and its derivatives obtained from Salicaceae species. The enzymatic catalysis of the decomposition of Salicaceae phenolic glucosides was tested using almond beta-glucosidase and rabbit and porcine liver esterases. The beta-glucosidase catalyzed the complete hydrolysis of salicin and salicortin, yielding saligenin and glucose. Salicortin also produced (+)-6-hydroxycyclohexen-2-one (6-HCH). The acylglucosides were not decomposed by the beta-glucosidase. Both esterases catalyzed the decomposition of tremulacin, salicortin, and 2'-O-acetylsalicortin, releasing tremuloidin, salicin, and 2'-O-acetylsalicin as the main products, accompanied by 6-HCH and catechol. Tremuloidin and 2'-O-acetylsalicin were quite stable under the esterase hydrolysis, and salicin was not decomposed at all.


New cytotoxic scalarane sesterterpenes from the Dictyoceratid sponge Strepsichordaia lendenfeldi. Nine sesterterpenes 1-9 have been isolated from a Dictyoceratid sponge, Strepsichordaia lendenfeldi, collected on the Great Barrier Reef, Australia. Seven of these compounds are new, one [4] had been reported previously as a semisynthetic product, and one [5] had been isolated previously from Carteriospongia foliascens. Unambiguous 13C- and 1H-nmr assignments have been made for 1 based on extensive 1D and 2D high field nmr experiments, which enabled 13C-nmr assignments to be made for 2-9. Significant growth inhibitory effects with tested cancer cell lines are reported for compounds 1-8.


Characterization of silkworm chlorophyll metabolites as an active photosensitizer for photodynamic therapy. Silkworm excreta containing chlorophyll metabolites have long been used for their medicinal activities in the Far East. The major chlorophyll derivative (CpD) fraction in the Me2CO extract from the silkworm excreta exhibits strong photodynamic action on mice and human tumor cells in vitro. The main CpD component was isolated, purified, and subjected to extensive structural and characterization studies to assess its photodynamic therapeutic activity. According to the spectral analyses, the structure of the major unknown CpD was determined to be 10-hydroxypheophytin a [1]. The CpD component possessed a high quantum efficiency (50%) for the photosensitized production of singlet molecular oxygen, thus providing a molecular basis for its photodynamic therapeutic efficiency. A further advantage is that the "photooxidation/degradation" product(s) from this CpD retains all the characteristics of a photodynamic sensitizer.


New phenolic glucosides from the leaves of Eurya tigang. Three new compounds, 6'-O-coumaroyl-1'-O-[2-(4-hydroxyphenyl)ethyl]-beta-D-glucopyra nos ide [1] (eutigoside A), 6'-O-coumaroyl-1'-O-[2-(1-hydroxy-4-oxo-2,5-cyclohexadien-1- yl)ethyl]-beta-D-glucopyranoside [2] (eutigoside B), and 6'-O-cinnamoyl-1'-O-[2-(1-hydroxy-4-oxo-2,5-cyclohexadien-1-yl)eth yl]- beta-D-glucopyranoside [3] (eutigoside C) have been isolated from the leaves of Eurya tigang, along with other known compounds (afzelin, quercitrin, p-coumaric acid, methyl-alpha-D-fructofuranoside, isorengyol, and euryanoside). Their structures were determined by chemical and spectroscopic methods (uv, ir, ms, 1H-1H COSY, and 1H-13C COSY).


Further bioactive acetylenic compounds from the Caribbean sponge Cribrochalina vasculum. In addition to the known 3-hydroxydocosa-(4E, 15E)-dien-1-yne [1], 3-hydroxy-16-methyleicos-(4E)-en-1-yne [2], and 3-hydroxy-19-methyleicos-(4E)-en-1-yne [3], the lipophilic extract of the Caribbean sponge Cribrochalina vasculum was shown to contain four new bioactive acetylene metabolites, (3R)-hydroxy-14-methyldocos-(4E)-en-1-yne [4], (3R)-hydroxy-16-methyleicos-1-yne [7], (3R)-hydroxy-19-methyleicos-1-yne [8], and docosa-(3E, 15Z)-dien-1-yne [9], whose structures were elucidated on the basis of chemical and spectral studies. The previously unassigned chirality at C-3 of the known compounds 1-3 has been also established as R.


Displacement activity of bisbenzylisoquinoline alkaloids at striatal 3H-SCH 23390 and 3H-raclopride binding sites. Fifteen bisbenzylisoquinoline alkaloids (BBIQ) with one ether bridge (thaligrisine [1], berbamunine [2], dimethylgrisabine [3], pampulhamine [4], and methyl-dauricine [5]), with two ether bridges (homoaromoline, isotetrandrine, and obaberine), with one ether bridge and one biphenyl bridge (oxandrine, dimethylpseudoxandrine, pseudoxandrine, and antioquine) or secoderivatives (secoobaberine, secoantioquine, and secolucidine), were tested for their ability to displace 3H-raclopride or 3H-SCH 23390 from their specific dopaminergic binding sites to rat striatal membranes. The most active compounds were found in the group of BBIQs with one ether bridge. Inactive or weakly active compounds were found in this group of BBIQs with one ether bridge and in the other groups. Analysis of tridimensional representations indicates that the differnt activities among the BBIQs with one ether bridge could be related to strong differences between the spatial occupancy of these compounds according to their stereochemistry.


Linear diterpenes from the Caribbean sponge Myrmekioderma styx. Four new oxygenated diterpenes 1-4 were isolated from the Caribbean sponge Myrmekioderma styx. The structures of these compounds were deduced by ms, uv, ir, 1H- and 13C-nmr, 1H-1H COSY, XHCORR, and COLOC experiments. Compounds 1-4 are lethal to brine shrimp (Artemia salina).


Clinically isolated lesions of the type seen in multiple sclerosis: a cognitive, psychiatric, and MRI follow up study. There is a dearth of longitudinal studies on psychometric and psychiatric change in multiple sclerosis (MS) particularly on the evolution of these abnormalities early in the disease process. A 4 1/2 year follow up study documenting magnetic resonance imaging (MRI), psychometric, and psychiatric abnormalities was undertaken in a group of 48 patients with clinically isolated lesions--for example, optic neuritis--which are frequently the harbinger of MS. At follow up about half the subjects had developed clinically definite MS, with memory deficits becoming apparent. Deficits in attention documented at initial assessment were present but unchanged in those subjects who still had a clinically isolated lesion status. However, after MS was categorised into a relapsing-remitting or chronic progressive course, patients with a chronic progressive course were found to have significantly deteriorated with regard to auditory attention tasks. T1 relaxation times in apparently normal white matter correlated with certain indices of cognitive impairment. In developing a model to explain the pathogenesis of intellectual and emotional change in MS, the interaction of organic, psychological, and social factors needs to be emphasised.


Multiple sclerosis in the Cambridge health district of east Anglia. A survey of multiple sclerosis (MS) in the Cambridge Health District has identified 374 cases in a population of 288,410, giving a prevalence of 130 per 100,000. A total of 322 cases (86%) had either clinically definite or probable multiple sclerosis on 1 July 1990 (112 per 100,000) and 52 cases (14%) had suspected multiple sclerosis (18 per 100,000.) The incidence during 1989-91 was 5.94 per 100,000 per year. The prevalence figure is higher than in recent surveys from other southern parts of the United Kingdom, but correction for the age and sex characteristics of the at risk population eliminates these differences. The overall prevalence of multiple sclerosis is probably between 108 and 120 per 100,000 in the southern United Kingdom.


Familial multiple sclerosis: MRI findings in clinically affected and unaffected siblings. Subclinical demyelinating lesions may occur in the brains of asymptomatic individuals, and the first-degree relatives of multiple sclerosis (MS) patients are at particular risk. Clinical and MRI examinations were performed in nine sibships from families with two or more cases of MS. These included 14 patients with clinically definite MS, three patients with clinically probable MS, and 27 asymptomatic siblings. Systematic criteria were applied to MRI interpretations to increase their specificity for MS. Thirteen (76%) of the 17 patients with MS showed lesions suggesting MS. Lesions were also found in six (38%) of the 16 asymptomatic siblings under age 50 and in eight (73%) of the 11 over age 50. Judged by stringent criteria, the lesions of only three (11%) of the 27 asymptomatic siblings were considered to be due to demyelination. The results demonstrate the occurrence of subclinical demyelination in asymptomatic siblings of MS patients and stress the importance of clinical follow up and MRI studies of the first-degree relatives when classifying them as healthy in family studies.


Postictal switch in blood flow distribution and temporal lobe seizures. The ictal increase of regional cerebral blood flow has yet to be fully utilised in the investigation of focal seizures. Although single photon emission tomography (SPECT) is being increasingly used in the localisation of epileptic foci, the evolution and time courses of the peri-ictal perfusion changes have yet to be clarified. We performed serial SPECT studies in the interictal, ictal and immediate postictal states in 12 patients with refractory temporal lobe epilepsy to define the patterns and duration of peri-ictal cerebral blood flow changes. Visual analysis showed a constant pattern of unilateral global increases in temporal lobe perfusion during seizures which suddenly switched to a pattern of relative mesial temporal (hippocampal) hyperperfusion and lateral temporal hypoperfusion in the immediate postictal period. Quantitative analysis confirmed the visual assessment. Lateral temporal cortex ictal/normal side to side ratios were increased by mean 35.1% (95% confidence interval 21.8% to 48.4%) more in the ictal studies than in the interictal studies and mesial temporal cortex ratios increased by mean 30.8% (22.4% to 39.2%). In the postictal state, however, lateral temporal ratios were reduced by mean 7.7% (-15.8% to 0.4%) compared with interictal values, whereas mesial temporal perfusion was maintained compared with the interictal studies. These observations provide critical information for interpreting scans which can be used in the localisation of epileptic foci. This postictal switch in blood flow patterns may reflect the underlying metabolic processes of neuronal activation and recovery and have implications for understanding the neurobiology of human epileptic seizures.


Central nervous system lesions in von Hippel-Lindau syndrome. CNS manifestations were studied in 97 gene carriers of von Hippel-Lindau syndrome (HLS). Haemangioblastomas of the CNS were found in 43 patients (44%), 23 females and 20 males. The mean age at diagnosis was 39 years (12-73 years). A total of 93 haemangioblastomas were detected of which 74% were intracranial and 26% were located in the spinal cord; 75% were predominantly cystic and 25% presented as solid lesions. Multiple lesions were found in 42% of HLS-associated haemangioblastomas, but in none of 51 patients with CNS haemangioblastoma without HLS. Haemangioblastoma was the cause of death in 82% of patients with HLS. Although microsurgery has considerably improved post-operative results, multifocal tumour development and recurrence remain a serious problem in the clinical management of HLS gene carriers.


Neurogenic effects on the palatopharyngeal muscle in patients with obstructive sleep apnoea: a muscle biopsy study. Muscle biopsies from the palatopharyngeal muscle of eight patients with obstructive sleep apnoea were performed during uvulopalatopharyngoplasty. Control biopsies were performed during tonsillectomy in seven control patients with no history of symptoms suggesting obstructive sleep apnoea. The diagnosis was based on the patient's history and a whole night recording of arterial oxygen saturation and respiration movements. The mean number of oxygen desaturations > or = 4% per sleeping hour was 39 (range 7-80) in patients with obstructive sleep apnoea. In the control patients the occurrence of muscle fibre type and size relation between type I and type II fibres were comparable to what is found in the quadriceps femoris muscle, but the mean size of the fibres was < 25% of what is found in limb muscles. All biopsies from patients with obstructive sleep apnoea showed abnormalities. Atrophy with a fascicular distribution, increased number of angulated atrophic fibres, a twin or multiple peak distribution of the fibre size spectra, and an abnormal distribution of fibre types in many muscle fascicles corresponding to "type grouping" all points to a neurogenic alteration. This neurogenic lesion may be a primary phenomenon or secondary to the trauma of repetitive and prolonged stretching of the pharyngeal structures during apnoeas. A disturbance of the function of the dilating muscles of the upper airway may be important in causing the abnormal airway collapse seen in obstructive sleep apnoea.


Lesions of basal ganglia due to disulfiram neurotoxicity. Three cases of disulfiram induced Parkinsonism and frontal lobe-like syndrome associated with bilateral lesions of the lentiform nuclei on CT scan are reported. Symptoms developed either after an acute high dose of disulfiram (one case) or after several days to weeks of disulfiram treatment (two cases) and persisted over several years in two patients. These observations suggest that basal ganglia are one of the major targets of disulfiram neurotoxicity. The mechanisms of the lesions of basal ganglia may involve carbon disulfide toxicity.


Thalamocortical diaschisis: positron emission tomography in humans. To investigate further the relations between cortical energy metabolism and neuropsychological impairment after unilateral thalamic lesion, 55 patients underwent positron emission tomography studies of either cortical oxygen consumption or glucose utilisation, including eight repeat studies, at times ranging from 4 days to 98 months after the onset of the lesion [stroke (n = 44) or stereotaxic VL-Vim thalamotomy performed for movement disorders (n = 11)]. Patients with thalamotomy were also studied preoperatively and the surgery induced a significant fall in cortical metabolism on both sides (more so ipsilaterally); post-operatively the magnitude of the ipsilateral cortex hypometabolism was positively correlated to the severity of global neuropsychological impairment; similar but less significant findings were obtained for the ipsilateral/contralateral cortical metabolic asymmetry. With respect to the whole patient sample, the cortical metabolic asymmetry was initially pronounced, with subsequent monoexponential recovery, in the cognitively impaired study group, but it was only mild and showed no meaningful trend for recovery in the cognitively unaffected study group; yet even soon (< 3 months) after thalamic lesion there was a noticeable overlap of individual asymmetry values among the two study groups. These results lend further support to the view that the neuropsychological impairment that frequently follows unilateral thalamic lesions is reflected in a depression of synaptic activity in both the overlying and the contralateral cerebral cortices. For individual patients, this study also illustrates the potentially misleading nature of the measured cortical metabolic asymmetry with respect to neuropsychological status, especially at late times after lesion, in part because side to side metabolic ratios do not reflect bilateral changes.


Cerebral symptoms after whiplash injury of the neck: a prospective clinical and neuropsychological study of whiplash injury. Twenty one unselected patients with an acute whiplash injury of the neck had neurological and neuropsychological assessment, cervical x rays, EEG, BAEP, MRI, and an otoneurological examination within two weeks of the injury. Subjectively, 13 patients reported concentration deficits, 18 reported sleep disturbances, 9 had symptoms of depression, and 7 female patients told of menstrual irregularities. Neuropsychological examination revealed significantly lower performance in tests related to attention and concentration compared to sex, age and educational matched control subjects. Otoneurological examination showed abnormalities in 9 of 17 whiplash subjects. EEG showed questionable changes in 8 of 18 recordings. MRI and BAEP were normal in all patients. Repeat neuropsychological testing in 15 patients at three months showed that attention deficits had improved but were still shown in 12 of 14 and the concentration deficits in 8 of 13 patients. At one year all patients had returned to work, 16 to full and 5 to part time employment. In 4, cognitive dysfunction remained the only significant problem. These findings are discussed as being compatible with possible damage to basal frontal and upper brain stem structures after whiplash injury of the neck.


Delayed radiation necrosis of the central nervous system in patients irradiated for pituitary tumours. Four cases of delayed radiation necrosis involving the CNS were found in a group of 46 patients irradiated for pituitary tumours over a six year period. This occurred in three of 11 patients with Cushing's disease representing an incidence of 27% in this group. There were no cases among 11 patients with acromegaly or among seven with prolactinomas. One case (6%) was found in the 17 patients with chromophobe adenomas. Standard doses of radiation were delivered to these patients and the findings support suggestions that the metabolic disturbances of Cushing's disease may reduce tolerance to radiation. Our results and a literature review indicate that if radiotherapy is used to treat Cushing's disease, the total dose should be less than 50 Gy at 2 Gy per day fractionation.


Heterogeneity in Alzheimer's disease: progression rate segregated by distinct neuropsychological and cerebral metabolic profiles. In an attempt to define possible subgroups of Alzheimer's disease, 21 patients satisfying current clinical diagnostic criteria for this disorder were divided on the basis of progression rates of symptoms. Thirteen patients with relatively rapid intellectual deterioration did not differ from eight patients showing slow progression with respect to global intellectual performance, sex, or age at onset of symptoms. Neuropsychological testing revealed that although the two groups were indistinguishable in verbal or visuospatial functions associated with the parietotemporal cortex, the more rapidly deteriorating group had significantly greater impairment in executive functions attributed to the frontal lobe. PET scans showed equivalent reductions in glucose metabolism in the parietotemporal cortex, but patients with relatively fast progression had significantly greater hypometabolism frontally. These results suggest an association between relatively severe frontal lobe involvement and a rapid clinical course that might have important implications for the development of treatment strategies for patients with Alzheimer's disease.


SPECT findings in Parkinson's disease associated with dementia. Dementia in Parkinson's disease is thought to be attributable not only to subcortical lesions but also to cortical alterations, especially frontal lobe dysfunction. To evaluate cortical function, the regional cerebral blood flow (rCBF) was estimated of 13 demented and 13 non-demented age matched patients with Parkinson's disease compared with that of 10 age matched controls using I-123 iodoamphetamine single photon emission tomography (IMP-SPECT). The rCBF of the nondemented Parkinson's patients showed no significant differences from that of the control subjects. In the demented patients, the bilateral frontal and parietal and left temporal regional blood flow was significantly less than in the controls. Four demented patients showed isolated frontal hypoperfusion, 8 showed fronto-parietal hypoperfusion, and 1 showed isolated parietal hypoperfusion. Frontal hypoperfusion was therefore present in 12 of the 13 demented patients, and this finding agrees with the frontal lobe dysfunction hypothesis. Parietal rCBF had a significant positive correlation with cortical functions such as calculation and language ability in the MMSE scores. The parietal and temporal reduction in rCBF probably reflects the presence of Alzheimer pathology, cortical Lewy body disease, or both.


Focal transcranial magnetic stimulation and response bias in a forced-choice task. The effects of transcranial magnetic stimulation were studied on the performance of a warned, forced-choice response time task by normal adults. The task consisted of extension of the index finger in response to the click produced by the discharge of the magnetic coil (go-signal). The subjects were asked to choose the right or left finger only after the go-signal was delivered. Single magnetic stimuli were delivered to the prefrontal or motor area, and in the control situation, away from the head. Magnetic stimulation affected hand preference only when it was delivered to the motor area. With stimulation of this area, subjects more often chose the hand contralateral to the site stimulated with response times that were mainly less than 200 ms. With longer response times (between 200 and 1100 ms), magnetic stimulation had no effect on hand preference regardless of the site stimulated. Stimulation of prefrontal areas yielded results similar to the control situation. These results suggest that response bias in this paradigm is caused by an effect of magnetic stimulation on neural structures within, or closely related to, the motor areas of the brain. Although the response bias was clear and predictable, the subjects were unaware of its existence. It is possible to influence endogenous processes of movement preparation externally without disrupting the conscious perception of volition.


Atrophy of medial temporal lobes on MRI in "probable" Alzheimer's disease and normal ageing: diagnostic value and neuropsychological correlates. Magnetic resonance imaging (MRI) has shown a great reduction in medial temporal lobe and hippocampal volume of patients with Alzheimer's disease as compared to controls. Quantitative volumetric measurements are not yet available for routine clinical use. We investigated whether visual assessment of medial temporal lobe atrophy (MTA) on plain MRI films could distinguish patients with Alzheimer's disease (n = 21) from age matched controls (n = 21). The degree of MTA was ascertained with a ranking procedure and validated by linear measurements of the medial temporal lobe including the hippocampal formation and surrounding spaces occupied by cerebrospinal fluid. Patients with Alzheimer's disease showed a significantly higher degree of subjectively assessed MTA than controls (p = 0.0005). Linear measurements correlated highly with subjective assessment of MTA and also showed significant differences between groups. Ventricular indices did not differ significantly between groups. In Alzheimer's disease patients the degree of MTA correlated significantly with scores on the mini-mental state examination and memory tests, but poorly with mental speed tests. This study shows that MTA may be assessed quickly and easily with plain MRI films. MTA shown on MRI strongly supports the clinical diagnosis of Alzheimer's disease, is related to memory function, and seems to occur earlier in the disease process than does generalised brain atrophy.


Hospital arrival time after onset of stroke. To estimate the proportion of patients with stroke likely to be eligible for a trial of anticoagulant treatment for acute ischaemic stroke, the interval between onset of symptoms and arrival at hospital was analysed prospectively. Of 773 patients with stroke admitted in one year, 63% arrived at hospital within 12 hours, 76% within 24 hours, and 85% within 48 hours of ictus. The arrival time varied significantly with stroke subtype. Patients with intracerebral haemorrhage tended to arrive earlier than those with cerebral infarct, who arrived sooner than those with lacunar infarct. The results suggest that about half of all patients with ischaemic stroke in Hong Kong would present within 12 hours of ictus, in time for inclusion in a therapeutic trial.


Actively and passively evoked P3 latency of event-related potentials in Parkinson's disease. Event-related potentials (ERPs) generated during the performance of visual discrimination tasks were studied in 31 patients with Parkinson's disease, 9 patients with Alzheimer's disease, and 37 normal control subjects. Actively and passively evoked P3 components (P3b and P3a) were respectively identified as the components of the P3 response to infrequent target stimuli and infrequent non-target stimuli. Both the P3a and P3b latencies were significantly prolonged by normal aging. Nine of the Parkinson's disease patients showed a P3b latency above the 95% confidence limit of the age-adjusted regression line based on the normal controls, while only on patient had a prolonged P3a latency. In 6 patients with demented Parkinson's disease, the P3b latency was significantly longer than in 15 age-equivalent normal subjects, although no significant difference was found in the P3a latency. On the other hand, patients with Alzheimer's disease showed significant prolongation of both the P3a and P3b latencies compared to the normal controls. Furthermore, there was a significant difference in P3a latency between patients with demented Parkinson's disease and those with Alzheimer's disease. These results suggest that the automatic processing stage associated with P3a may be less impaired than the attention-controlled processing reflected by P3b in patients with Parkinson's disease, and also indicate that there may be some differences in the changes of cognitive processing caused by Parkinson's disease and Alzheimer's disease.


The epidemiology of multiple sclerosis: the Iceland model. Onset-adjusted prevalence rate and other methodological considerations. The epidemiology of multiple sclerosis (MS) is characterized by the fact that there is an uneven distribution of the disease throughout the world. The two most commonly used indices of its frequency are the incidence and prevalence rates. The incidence rate reflects, to a great extent, the influence of environmental factors in triggering the clinical manifestations of the disease, if it is based upon the actual date of the initiation of symptoms, rather than the date of diagnosis. The prevalence rate is currently based on the date of diagnosis and includes all MS patients who are alive on a particular date, without regard to their ethnic origin, the site and the duration of residence or any other factors that may have influenced the acquisition of the disease. We propose that in order to make the concept of the prevalence rate possibly more meaningful, the term should refer, retrospectively, to all patients whose symptoms eventually led to the diagnosis of MS, even though the diagnosis was not yet established on an earlier prevalence day. In addition, only patients of the same ethnic background who have spent their prepuberal years in the geographical area under study should be included. We are calling this measure the onset-adjusted prevalence rate. Another problem encountered in epidemiological studies of MS relates to the common practice of adjusting prevalence data obtained for age and sex in one area to what is referred to as a "standard" American (or world) population, groups of great ethnic and age diversity. It is also curious that in many studies the bases for comparison of populations are census data obtained many years previously. We suggest that age and sex adjustment should be applied only to similar ethnic groups born and raised under different environmental conditions. We believe that data obtained by calculating an onset-adjusted prevalence rate restricted to a homogeneous group of patients sharing the same environment during the prepuberal years may provide valuable etiological clues.


Cerebral microcirculatory changes during and following transient ventricular tachycardia in cats. Although reduced cerebral perfusion is believed to be the cause of syncope due to cardiac arrhythmias, investigations on the cerebral microcirculation during cardiac arrhythmias have been rare. We therefore studied the effects of transient ventricular tachycardia on the local cerebral blood volume and blood flow. Experimental ventricular tachycardia was induced in cats by electrically stimulating the ventricle of the heart at a rate of 300/min for 1 min. Using our photoelectric method, the local cerebral blood volume, mean transit time of blood, and cerebral blood flow in the parieto-temporal region were measured during and for 3 h after ventricular tachycardia. Transient ventricular tachycardia of as short as 1 min caused cerebral ischemia with a blood flow reduction of approximately 30%. This was considered to be due to reduced blood pressure plus transient autonomic dysfunction, or dysautoregulation, during the ventricular tachycardia. Mild and transient reactive hyperemia occurred immediately after termination of the dysrhythmia, but continuous reductions of cerebral blood flow were observed thereafter for 3 h. This delayed hypoperfusion is attributable to either vasoconstriction of the large resistance vessels or changes in the hemorheological properties of the blood caused by cerebral ischemia. Ventricular tachycardia of the type reported has significant and long-lasting effects on the cerebral microcirculation.


Autopsy report of primary CNS B-cell lymphoma indistinguishable from multiple sclerosis: diagnosis with the immunoglobulin gene rearrangements analysis. We report a case of primary CNS B-cell lymphoma indistinguishable from multiple sclerosis (MS). MRI of the head showed the spontaneous disappearance of the white matter lesions and the progressive cerebral atrophy. The brain biopsy failed to make a diagnosis of CNS lymphoma but rather suggested MS. Although the primary CNS lymphoma was suspected at autopsy, the immunohistochemical study showed the CNS-infiltrating lymphoid cells comprising both T-cells and B-cells. Analysis of the immunoglobulin and T-cell receptor gene rearrangements first provided evidence of primary CNS B-cell lymphoma.


Corticospinal conduction studied with magnetic double stimulation in the intact human. A group of 8 healthy normal subjects (24-36 years old, mean age 29 years) were investigated. Transcranial magnetic double stimulation of the motor cortex was carried out at different interstimulus intervals. With both stimuli suprathreshold, an attenuation of the test response was found at interstimulus intervals of less than 200 msec (target relaxed or contracted). The manifestation of this attenuation correlated with central signs in 31 patients with multiple sclerosis. This phenomenon is (at least at longer intervals) probably not a result of the refractory spinal motoneuron pool, but of a supraspinal inhibitory mechanism or lack of corticospinal drive caused otherwise. At interstimulus intervals between 10 and 30 msec, the test response increases significantly (magnetic double stimulation 10% suprathreshold, target relaxed). This result is also seen with voluntary muscle contraction and with vibration applied to a relaxed target muscle. The facilitatory effect is probably caused by slowly conducted corticospinal volleys enabling summation, with descending impulses generated by the test stimulus. With the conditioning stimulus subthreshold and target muscle relaxed an intracortical inhibition of the test response could be confirmed at short interstimulus intervals.


An insert mutation in the chromosome 20 amyloid precursor gene in a Gerstmann-Sträussler-Scheinker family. We report the finding of an insert mutation in the chromosome 20 amyloid precursor gene in a family with neuropathologically-verified, experimentally-transmitted Gerstmann-Sträussler-Scheinker syndrome (GSS). The insert consisted of 8 extra copies of a repeating octapeptide coding sequence in the region between codons 51 and 91; it was identified in the proband and a presently unaffected at-risk niece by full sequencing of the open reading frame, and was visualized electrophoretically in the proband and 6 of 12 at-risk relatives. Although affected members in this French-Breton family have shown a variety of clinical profiles, including durations of illness that ranged from 3 months to 13 years, all autopsied cases (including the patient with the shortest illness) have had the distinctive multicentric amyloid plaques that define GSS as a nosologic entity.


Increased striatal 18F-dopa uptake and normal glucose metabolism in idiopathic dystonia syndrome. Striatal 18F-Dopa uptake and glucose metabolism were studied by positron emission tomography with 6-L-[18F]fluorodopa and [18F]fluorodeoxyglucose, respectively, in 8 patients with idiopathic dystonia. Patients with abnormal findings on the brain CT and MRI were excluded from this study. The clinical diagnosis consisted of torsion dystonia in 3 patients, focal dystonia limited in the arm in 3 and cervical dystonia (spasmodic torticollis) in 2. The 18F-Dopa uptake, corrected by nonspecific retention in the cerebellum, at 120 min post-administration was evaluated, and increased 18F-Dopa uptake in the putamen and in the caudate head was observed in the patients with idiopathic dystonia compared to the normal controls. The striatal glucose metabolism in the patients with idiopathic dystonia showed no difference with the normal controls. These findings suggest that pathogenetic mechanism of idiopathic dystonia involves increased presynaptic activity of the dopaminergic system in the striatum.


Endoneurial blood supply to peripheral nerves is not uniform. Peripheral nerves are not uniformly susceptible to the effects of ischemia in human and experimental ischemic neuropathies. Since endoneurial blood flow is directly proportional to the number of endoneurial capillaries, we studied endoneurial capillary density at multiple levels of the peripheral nerves of normal rats. Capillary density was lowest in the sciatic and proximal tibial nerves and significantly higher in dorsal and ventral roots and distal tibial and plantar nerves. Endoneurial capillary density corresponds to the hierarchy of susceptibility to ischemic nerve damage in human and experimental ischemic neuropathies. These findings suggest that susceptibility of peripheral nerves to ischemia is determined, at least in part, by the density of endoneurial capillaries.


Regeneration after free muscle grafting in normal and dystrophic (mdx) mice. Soleus muscles from C57BL/10 and mdx mice were isotransplanted to induce a cycle of degeneration/regeneration. Sixty days post-surgery, transplanted and contralateral soleus muscles were removed for mechanical and biochemical analyses. The regeneration which occurs after transplantation, induces in both mdx and C57BL/10 soleus muscles a decrease in maximal isometric force, together with an increase of the velocity of contraction. This increase in velocity is accompanied by the expression of typically fast-type myosin heavy chains. Thus degeneration/regeneration of both mdx and normal mice are very similar, causing a shift towards physiologically 'faster' muscle. Previous physiological and biochemical studies of mdx muscles have shown that mdx muscle is shifted towards 'slower' muscle compared to normal mice. One explanation of these findings was that the degeneration/regeneration cycles inherent in dystrophin-deficient mdx muscle causes a shift towards 'slow'. Our results argue against this hypothesis: degeneration/regeneration in both normal and mdx mice causes a shift towards 'fast'.


Dilating cardiomyopathy as the expression of Xp21 Becker type muscular dystrophy. A 35-year-old man with severe progressive dilating cardiomyopathy and no clinical signs of muscle disease underwent muscular investigations because of markedly increased serum creatine kinase. Muscle biopsy demonstrated Becker type muscular dystrophy with dystrophin of low molecular weight. Genetic analysis showed a deletion spanning from exon 45 to exon 46 in the Xp21 region. Xp21 Becker type muscular dystrophy must be considered in the differential diagnosis of dilating cardiomyopathy.


Use of single strand conformation polymorphism analysis to detect point mutations in human mitochondrial DNA. Myoclonus epilepsy with ragged-red fibers (MERRF) has been shown to be associated with a specific point mutation at the nucleotide 8344 in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). We screened 6 patients with clinically diagnosed MERRF and 1 patient with ocular myopathy for point mutations in the tRNA(Lys) gene, using single strand conformation polymorphism (SSCP) analysis, which can detect even a 1-basepair difference between 2 DNA sequences. Using SSCP and consequent DNA sequencing, we identified the known MERRF mutation in 4 out of 6 MERRF patients, as well as in 1 patient with a new clinical phenotype associated with this mutation: progressive external ophthalmoplegia, muscle weakness and a lipoma, but no myoclonus or epilepsy. Two of the patients with clinical MERRF had neither the MERRF-mutation nor any other mutations in the tRNA(Lys) gene. Using SSCP analysis, we also detected a new polymorphism in 1 patient. Thus, SSCP analysis can be applied to search effectively and rapidly for point mutations or polymorphisms in mitochondrial DNA.