Stress-Induced Haematohidrosis: a Case Report

We describe a case of stress-induced haematohidrosis in a 14-year-old boy who responded well to stress management together with sertraline medication.

Cardiological society of India document on safety measure during echo evaluation of cardiovascular disease in the time of COVID-19

An echocardiographic investigation is one of the key modalities of diagnosis in cardiology. There has been a rising presence of cardiological comorbidities in patients positive for COVID-19. Hence, it is becoming extremely essential to look into the correct safety precautions, healthcare professionals must take while conducting an echo investigation. The decision matrix formulated for conducting an echocardiographic evaluation is based on presence or absence of cardiological comorbidity vis-à-vis positive, suspected or negative for COVID-19. The safety measures have been constructed keeping in mind the current safety precautions by WHO, CDC and MoHFW, India.

Cardiological Society of India: Document on acute MI care during COVID-19

The unprecedented and rapidly spreading Coronavirus Disease-19 (COVID-19) pandemic has challenged public health care systems globally. Based on worldwide experience, India has initiated a nationwide lockdown to prevent the exponential surge of cases. During COVID-19, management of cardiovascular emergencies like acute Myocardial Infarction (MI) may be compromised. Cardiological Society of India (CSI) has ventured in this moment of crisis to evolve a consensus document for care of acute MI. However, this care should be individualized, based on local expertise and governmental advisories.

Experimentelle Grundlagen für die therapeutische Anwemcltimg von Ginkgoextrakt EGb 761

Monoextrakte aus den Blättern des Ginkgobaumes (Ginkgo biloba L.) werden zur Behandlung von peripheren und zentralen Durchblutungsstörungen sowie bei nachlassender intellektueller Leistungsfähigkeit eingesetzt. Der Spezialextrakt EGb 761 wird in einem standardisierten, vielstufigen Produktionsverfahren gewonnen. Ziel des Herstellungsprozesses ist neben der Anreicherung aktiver Inhaltsstoffe die weitgehende Entfernung von Substanzen mit unerwünschten Eigenschaften. Die experimentellen Befunde zeigen, daß dieser Extrakt pharmakologische Effekte auf alle wesentlichen, an der Blutversorgung beteiligten Komponenten ausübt. Auf der Gefäßebene bewirkt EGb 761 eine Steigerung der lokalen Durchblutung, beeinflußt den Arterienund Venentonus, vermindert eine erhöhte Kapillarpermeabilität und stimuliert die endotheliale Prostazyklinsynthese. Die Wirkungen auf das Blut umfassen unter anderem eine Verbesserung der rheologischen Eigenschaften, eine Stabilisierung der Erythrozytenmembran und die Hemmung PAF-vermittelter Reaktionen. Im Gewebe erhöht EGb 761 die Hypoxietoleranz, besitzt antiischämische Eigenschaften, verbessert den Energiemetabolismus und schützt vor Radikalinduzierten Schädigungen durch Hemmung und Neutralisierung von freien Radikalen.

Enteric fever in an HIV/AIDS patient: Atypical manifestations

Bloodstream infections with Salmonella typhi, is uncommon in human immunodeficiency virus (HIV)-infected persons. The symptoms in such patients are often non-specific and have a rather insidious onset and progression. We report a patient with sepsis and lower limb gangrene due to Salmonella typhi infection in an HIV-infected patient.

Validity of quantitative unspun urine microscopy, dipstick test leucocyte esterase and nitrite tests in rapidly diagnosing urinary tract infections

OBJECTIVES

Rapid diagnostic tests can screen out negative samples and can save valuable time and money. The study was conducted to assess the usefulness of leukocyte esterase, nitrate reductase and quantitative microscopic unspun urine wet mount examination in rapidly diagnosing urinary tract infections (UTI).

METHODS

Four hundred and fifty samples were tested by semi-quantitative culture on cysteine lactose electrolyte deficient medium, microscopic examination of unspun urine for significant pyuria, dipstick leucocyte esterase test (LET) and nitrite test (NT). Culture was used as gold standard to evaluate the performance of direct microscopy and dipstick tests.

RESULTS

Urine culture examination revealed significant bacteriuria (>10(5) cfu/ml) 98 (21.8%), in urine samples. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and the diagnostic odds ratio (DOR) of the dip-stick LET were 73.5%, 58.5%, 33.0%, 88.8%, and 3.9 respectively; those of the dip-stick NT were 57.1%, 78.7%, 42.7%, 86.8%, and 4.9 respectively; and those for microscopic significant pyuria detection were 68.4%, 60.8%, 32.7%, 87.3%, and 3.4 respectively. Highest sensitivity (95.9%), NPV (97.9%) and DOR (25.7) was obtained on combining microscopy and dip-stick LET and NT (either of them positive). This can potentially cut costs by 79%.

CONCLUSION

Quantitative unspun urine wet mount microscopy and dipstick tests for leucocyte esterase and nitrite test should be added into routine laboratory practices for faster diagnosis of UTI.

Percuteneous mitral balloon valvuloplasty in patients with post surgical mitral restenosis: result of 70 cases

OBJECTIVE

To evaluate the immediate results of balloon mitral valvulplasty in mitral restenosis patients with previous surgical mitral commissurotomy.

METHODS

Percuteneous balloon mitral valvuloplasty (BMV) was done in 145 cases of which 70patients had the history of previous surgical commissurotomy (Group I) and 75 patients were the new cases for the BMV (Group II).

RESULTS

In group I the age range was 35-65 years. In group I the duration of surgical commissurotomy (SC) was of 2-18 years past. In this group the result of balloon mitral valvuloplasty (BMV) was successful in 69 cases. Mitral valve area (MVA) before the procedure was 0.5-0.9 sq cm with mean 0.7 +/- 0.2 sq cm. Following procedure the MVA was 1.2-2.0 cm2 with a mean of 1.6 +/- 0.4 cm2. Mean gradient across mitral valve (MV) before the procedure was 15-25 mm of Hg with a mean 20 +/- 5 mm of Hg and after the procedure was 3-5 mm Hg with a mean of 4 +/- 1 mm Hg. In Group I, MVA > 1.8 cm2 was achieved in 25 cases & > 1.2-1.8 cm2 in 44 cases. Mitral regurgitation > or = grade 1 occurred in 8 cases (compared to previous echocardiography). In group II the age range was between 35-60 years. The result of BMV was successful in 74 cases. MVA before the procedure was 0.4-1.2 cm2 with a mean of 0.8 +/- 0.4 cm2. Following the procedure MVA was 1.3-2.1 cm2 with a mean of 1.7 +/- 0.4 cm2. Mean gradient across the mitral valve before the procedure was 15-29 mm of Hg with a mean of 22 +/- 7 mm of Hg. Mean gradient across the mitral valve after the procedure was 2-4 mm of Hg with a mean of 3 +/- 1 mm of Hg. MVA more than 1.8 cm2 was achieved in 29 cases and between 1.3-1.8 in 45 cases.

CONCLUSION

BMVin patients with mitral restenosis following Surgical mitral commissurtomy can be performed with almost similar success rate like that of BMV for the first time with low risk of major cardiac complication.

Simple 2,4-diacylphloroglucinols as classic transient receptor potential-6 activators--identification of a novel pharmacophore

The naturally occurring acylated phloroglucinol derivative hyperforin was recently identified as the first specific canonical transient receptor potential-6 (TRPC6) activator. Hyperforin is the major antidepressant component of St. John's wort, which mediates its antidepressant-like properties via TRPC6 channel activation. However, its pharmacophore moiety for activating TRPC6 channels is unknown. We hypothesized that the phloroglucinol moiety could be the essential pharmacophore of hyperforin and that its activity profile could be due to structural similarities with diacylglycerol (DAG), an endogenous nonselective activator of TRPC3, TRPC6, and TRPC7. Accordingly, a few 2-acyl and 2,4-diacylphloroglucinols were tested for their hyperforin-like activity profiles. We used a battery of experimental models to investigate all functional aspects of TRPC6 activation, including ion channel recordings, Ca(2+) imaging, neurite outgrowth, and inhibition of synaptosomal uptake. Phloroglucinol itself was inactive in all of our assays, which was also the case for 2-acylphloroglucinols. For TRPC6 activation, the presence of two symmetrically acyl-substitutions with appropriate alkyl chains in the phloroglucinol moiety seems to be an essential prerequisite. Potencies of these compounds in all assays were comparable with that of hyperforin for activating the TRPC6 channel. Finally, using structure-based modeling techniques, we suggest a binding mode for hyperforin to TRPC6. Based on this modeling approach, we propose that DAG is able to activate TRPC3, TRPC6, and TRPC7 because of higher flexibility within the chemical structure of DAG compared with the rather rigid structures of hyperforin and the 2,4-diacylphloroglucinol derivatives.

Cognitive and other behavioral effects of EGb 761 in animal models

Extensive pre-clinical and clinical studies conducted over more than three decades have established that EGb 761 (definition see editorial) represents a polyvalent therapeutic principle that is useful in the therapy of mildly to moderately severe dementia and other cognitive disorders. Besides cognition, other emotional and affective aspects of brain function also seem to benefit from EGb 761 treatment. Extensive behavioural studies in experimental animals are generally in line with clinical data since cognition improvement, stress protection, and antidepressive effects have been identified with this extract in proper animal models. While individual effects in all areas have been reported for adult animals and acute dosing, more pronounced effects are usually seen in aged animals and after subchronic treatment. Specifically, for the cognition improving properties pronounced beneficial effects are mainly present in those situations where cognition was impaired by aging or other noxious stimuli. Since all these conditions are associated with mitochondrial dysfunction, the stabilizing or even protecting effect of EGb 761 on mitochondrial function seems to be a major mechanism associated with many of EGb 761's behavioural effects. Bilobalide is most important in this respect. Moreover, bilobalide and the ginkgolides have recently been shown to affect chloride conductance by interfering with the function of membrane proteins related to receptor-gated chloride channels. These mechanisms are probably associated with behavioural effects requiring acute changes of neuronal activity, but might indirectly also improve mitochondrial function.

Structure-activity studies with Ginkgo biloba extract constituents as receptor-gated chloride channel blockers and modulators

The constituents of Ginkgo biloba leaf extract, ginkgolides A, B, C and J are known as effective antagonists of platelet-activating factor (PAF). Here, we will demonstrate that these substances are also effective blockers of glycine-activated chloride channels in the hippocampal neurons of rat. As examined in several other voltage- and ligand-operated channels, this ginkgolide action is selective. The blocking action of all tested ginkgolides is use-dependent--they block open glycine-activated channels. The IC (50) values for saturating blocking action of ginkgolides B and C are 0.273 microM and 0.267 microM, respectively, while ginkgolides A and J are less effective--IC (50) values are 1.97 microM and 2.0 microM. Corresponding dose-response relationships are close to single-site binding isotherms. Another constituent of EGb 761, bilobalide, is a weak inhibitor of NMDA receptor-activated current. Its synthetic analogue, NV-31, demonstrates a weak facilitatory action on Gly-activated conductance. Novel findings have indicated the possibility that the unique modulating activity profiles of the EGb 761 (definition see editorial) constituents examined are due to their effects on the anion homeostasis of central neurons.

Excitotoxic hippocampal membrane breakdown and its inhibition by bilobalide: role of chloride fluxes

We have previously shown that hypoxia and N-methyl-D-aspartate (NMDA) receptor activation induce breakdown of choline-containing phospholipids in rat hippocampus, a process which is mediated by calcium influx and phospholipase A (2) activation. Bilobalide, a constituent of Ginkgo biloba, inhibited this process in a potent manner (Weichel et al., Naunyn-Schmiedeberg's Arch. Pharmacol. 360, 609-615, 1999). In this study, we used fluorescence microscopy and radioactive flux measurements to show that bilobalide does not interfere with NMDA-induced calcium influx. Instead, bilobalide seems to inhibit NMDA-induced fluxes of chloride ions through ligand-operated chloride channels. In our experiments, substitution of chloride in the superfusion medium fully blocked the effect of NMDA on choline release from hippocampal slices, while the presence of chloride transport inhibitors (furosemide, DIDS) was partially antagonistic. The inhibitory effect of bilobalide and of HA-966, a glycine B receptor antagonist, on NMDA-induced choline release was attenuated in the presence of glycine. The inhibitory effect of bilobalide, but not that of HA-966, was also antagonized by GABA. The inhibitory effect of MK-801, an NMDA channel blocker, on choline release was insensitive to glycine. We conclude from our findings that bilobalide inhibits an NMDA-induced chloride flux through glycine/GABA-operated channels, thereby preventing NMDA-induced breakdown of membrane phospholipids. This effect is expected to contribute to the neuroprotective effects of ginkgo biloba extracts.

St John's wort (Hypericum perforatum) modulates evoked potentials in guinea pig hippocampal slices via AMPA and GABA receptors

The effects of an ethanolic extract of the plant Hypericum perforatum L. (St John's wort) (HYP) and its hydrosoluble fraction (HYPWS) on electrically evoked population spikes and fEPSP were investigated in this study. Concentration dependent (10(-6) to 10(-4) g/l) excitatory effects were found. Above concentrations of 10(-3) g/l, HYP reduced the evoked responses, whereas HYPWS further increased them. Paired pulse facilitation was unaffected with HYPWS (10(-4) to 10(-2) g/l). The excitatory effects of HYPWS were amplified by the GABA(A) and GABA(B) receptor antagonists bicuculline and phaclofen, respectively. These excitations were antagonised by the AMPA receptor antagonist CNQX. Excitations caused by hypericum were not antagonised by the NMDA receptor antagonists D-APV and MK801, the metabotropic glutamate receptor (type I and II) antagonist MCPG, or the L-type calcium channel blocker verapamil. Hypericin and hyperforin, two components of H. perforatum, were found not to be responsible for the excitatory effects of the extract.

Effects of bilobalide on amino acid release and electrophysiology of cortical slices

This study investigated the effects of bilobalide, a constituent of Ginkgo biloba, on potassium and veratridine-induced release of glutamate and aspartate from mouse cortical slices. We also studied its effects on spontaneous and N-methyl-D-aspartate (NMDA)-induced depolarizations elicited in magnesium-free artificial cerebrospinal fluid (aCSF) as well as its effect on NO-711 (a gamma-aminobutyric acid (GABA) uptake inhibitor)-induced depolarizations. Bilobalide, 100 microM significantly reduced both glutamate and aspartate release elicited by potassium or veratridine. Bilobalide (5-100 microM) also significantly reduced the frequency of NO-711 induced depolarizations, however, it had no effect on spontaneous or on NMDA-induced depolarizations at 5-200 microM. These results suggest that the neuroactive properties of bilobalide may be mediated by a reduction in excitatory amino acid neurotransmitter release.

Effect of Ginkgo biloba extract (EGb761) on glucose metabolism-related markers in streptozotocin-damaged rat brain

To reveal whether an extract of Ginkgo biloba (EGb761) may affect streptozotocin (STZ)-induced impairments in brain glucose metabolism, autoradiographies of [3H]cytochalasin-B binding to the total population of glucose transporters, [125I]insulin binding to insulin receptors, [3H]glyburide binding to sulfonylurea receptors, and radioactive in situ hybridization for GLUT3 mRNA were carried out in hippocampal brain sections of adult rats that have additionally been divided into good performers (GP) and poor performers (PP) by behavioural tests before the experiments. The STZ-induced increases in hippocampal [3H]cytochalasin-B binding to (total) glucose transporters returned to almost normal values following EGb761 treatment, regardless of the experimental animal group (GP or PP) tested. Similarly, the STZ-mediated enhancements in hippocampal insulin receptor binding of GP rats were partially compensated by the treatment with EGb761. The data suggest beneficial effects of EGb671 on impaired brain glucose metabolism, at least under the experimental conditions used in the study presented.

The antiepileptic drug losigamone decreases the persistent Na+ current in rat hippocampal neurons

The tetronic acid derivative losigamone is a new anticonvulsant drug with a mechanism of action that was previously unknown. The drug decreases the frequency of spontaneous action potentials and suppresses repetitive firing of neurons. Here we tested the hypothesis that losigamone suppresses the persistent Na+ current (I(NaP)) in hippocampal neurons of rat brain slices and in cultured hippocampal neurons. Whole-cell voltage clamp recordings from neurons of juvenile rats (P15-P25) were performed with pipettes filled with Cs-gluconate or CsF. After pharmacological block of K+ and Ca2+ currents I(NaP) was revealed by applying slow depolarizing voltage ramps from -70 to 0 mV. Losigamone (100-200 microM) was dissolved in DMSO (0.1%) and was applied by bath application or local pressure application. Losigamone induced a decrease in amplitude of I(NaP) at depolarized membrane potentials which was reversible in cultured neurons. When tetrodotoxin (TTX) was added to the bath, I(NaP) was blocked and only a residual non-specific outward cation current (I(cat)) remained. Losigamone had no obvious effect on responses to voltage ramps under these conditions. Thus, losigamone did not affect I(cat) or induce any additional currents. The data suggest that losigamone decreases neuronal excitability via a decrease in I(NaP).

Hyperforin stimulates intracellular calcium mobilisation and enhances extracellular acidification in DDT1-MF2 smooth muscle cells

Hyperforin, an acylphloroglucinol derivative, is a major constituent of St. John's wort extract (Hypericum perforatum L.), which is used in treating depressive disorders. Hyperforin has been demonstrated as a modulator of several neuronal ion channels, and inhibits smooth-muscle contraction induced by various neurotransmitters. To evaluate the spasmolytic properties of hyperforin in more detail, we performed studies on the hamster vas deferens smooth muscle cell line DDT1-MF2. In a first series of experiments, we determined the effect of hyperforin on intracellular Ca2+ concentration ([Ca2+]i) using the fluorochrome fura-2. These investigations were supplemented in a second series of assays, where the effects on cellular metabolism were analysed by measuring the rate of extracellular release of acidic metabolites with the help of a microphysiometer. Hyperforin (0.3-10 microg/ml) caused a concentration-dependent elevation of [Ca2+]i and extracellular acidification rate (ECAR). Both of these effects were independent of extracellular Ca2+. To elucidate whether the increase of [Ca2+]i by hyperforin causes or results from its ECAR-stimulating properties, we used various pharmacological tools to reveal the sequence of events and the molecular mechanisms involved. Our results suggest that hyperforin induces release of Ca2+ from as yet unidentified sources. Since the ECAR stimulation was inhibited to a different extent by the intracellular Ca2+ chelator BAPTA as well as by inhibitors of plasmalemmal and mitochondrial Na+/Ca2+ exchange, but not by inhibitors of Na+/H+ antiport, the intracellular Ca2+ increase seems to be essential for this hyperforin effect. However, further studies are needed to establish the exact mode of action, and to deduce whether this aspect of hyperforin activity contributes to its antidepressant and neuroprotective effects.

Stimulation of glutamate, aspartate and gamma-aminobutyric acid release from synaptosomes by hyperforin

Hyperforin is one pharmacologically active constituent of the medicinal herb Hypericum perforatum. The mechanism of its antidepressant-like activity is currently considered to be the inhibition of synaptic reuptake of neurotransmitters. Here, we will demonstrate that it also stimulates the release of glutamate from rat cortical synaptosomes, and that this effect is preceded by an increase in their free calcium [Ca2+]i levels. These hyperforin-related effects were also observed in the absence of Ca2+ in the medium. Although we noted enhanced glutamate, aspartate and GABA release under the influence of hyperforin, the release of various other amino acids was not enhanced. In contrast, reserpine did not influence the release of any of the amino acids studied. Adding hyperforin to synaptosomal suspension decreased their pHi, which returned to basal levels under certain incubation conditions. It also prevented the generation of ATP-induced pH gradients of isolated synaptic vesicles, and preformed pH-gradients were reversed by it. We will discuss the implications of our studies in understanding the mechanisms of hyperforin activity in relation to current findings on its pharmacological activity profile. Our observations suggest that neurotransmitter release stimulation from synaptosomes and the previously reported reuptake inhibitory properties of hyperforin are consequences of its effects on synaptosomal ionic homeostasis, and that it is not a reserpine-like agent.

Modulation of ion channels in rat neurons by the constituents of Hypericum perforatum

Despite almost forty years of widespread use of antidepressant drugs, their mode of action is still unknown. Hyperforin, a phloroglucinol derivative, is a major pharmacologically and therapeutically active constituent of Hypericum perforatum extract that is widely used as an herbal antidepressant drug. However, the mechanism or mechanisms of action of these naturally abundant, non-toxic extracts remain unclear. Enzymatically isolated patch-clamped rat central and peripheral neurons exposed to rapid changes in the composition of external medium (concentration clamp) were used in our experiments to investigate the modulation of the various voltage- and ligand-gated channels by hyperforin, as well as by other constituents of Hypericum perforatum. At nanomolar concentrations, hyperforin induced significant inhibition of various ion channels. In the case of P-type Ca2+ channels, we established that hyperforin acts via interaction with calmodulin or through calmodulin-activated pathways involving at least one second messenger. The results presented here indicate that multiple mechanisms and extract constituents may be involved in the antidepressant action of Hypericum extracts, and that they could also possess neuroprotective and analgesic effects.

Effects of Hypericum perforatum L. on evoked potentials in guinea pig hippocampal slices

Therapeutic uses of Hypericum extracts have been demonstrated as safe and effective in treating mild to moderate depression in numerous clinical trials. To date, however, no definitive statements on their mode of action can be made, and little information on their electrophysiological effects is available. The present communication summarises the results of our efforts directed towards clarifying the effects of an ethanolic Hypericum extract (HYP) and its hydrosoluble fraction (HYPWS), and two of its constituents hypericin and hyperforin on electrically evoked population spikes in guinea pig hippocampal slices. In higher concentrations (>10 microM), the two extract constituents tested revealed inhibitory effects only, whereas concentration-dependent (between 10(-6) to 10(-4) g/l) excitatory effects were observed for HYP and HYPWS. The excitatory effects were strongly amplified by the GABA(B) antagonist phaclofen, whereas the effects of bicucullin, a GABA(A) antagonist, were marginal. The excitations were completely blocked by the AMPA antagonist CNQX, but not by the NMDA antagonists APV and MK801 or the L-type calcium-channel blocker verapamil. This kind of excitatory effect on the hippocampus is unknown in other antidepressants and; indeed, many of the latter reduce neuronal excitability. We conclude, therefore, that the mechanisms involved in the antidepressant activity of Hypericum extracts are different from those of conventional antidepressants, and that identifying their excitatory components may facilitate their more rational standardisation.

Hypericum extract and hyperforin: memory-enhancing properties in rodents

Effects of a Hypericum extract in therapeutic use and hyperforin sodium salt were evaluated in rat and mouse avoidance tests. In a conditioned avoidance response (CAR) test on the rat, oral daily administration of hyperforin (1.25 mg/kg/day) or of the extract (50 mg/kg/day) before the training sessions considerably improved learning ability from the second day onwards until the day 7. In addition, the memory of the learned responses acquired during 7 consecutive days of administration and training was largely retained even after 9 days without further treatment or training. The observations made using different doses indicate that these learning-facilitating and/or memory-consolidating effects by the agents follow inverse U-shaped dose-response curves in dose ranges lower than (for hyperforin) or equal to (for Hypericum extract) their effective dose in the behavioral despair test for antidepressants. In a passive avoidance response test on the mouse, a single oral dose (1.25 mg/kg) of hyperforin not only improved memory acquisition and consolidation, but also almost completely reversed scopolamine-induced amnesia. The single Hypericum extract dose tested (25 mg/kg) did not reveal any significant effects in the passive avoidance response (PAR) test on the mouse. These observations suggest that the Hypericum extract could be a novel type of antidepressant with memory enhancing properties, and indicate that hyperforin is involved in its cognitive effects. Pure hyperforin seems to be a more potent antidementia agent than an antidepressant.

Evidence for immunotoxic effects of crude Ginkgo biloba L. leaf extracts using the popliteal lymph node assay in the mouse

Allergic reactions due to contact with different parts of the ancient tree Ginkgo biloba L. have repeatedly been reported. Provocation tests in patients and animal experiments have identified alkylphenols such as ginkgolic acids as causative constituents. Leaf extracts from Ginkgo are widely used to treat peripheral or cerebral circulatory disorders and Alzheimer's disease. Since alkylphenols are also present in leaves, potential allergic and other immunological hazards of such preparations have to be carefully controlled. Thus, we have evaluated if the popliteal lymph node assay (PLNA) in the mouse may represent a suitable model for the detection of constituents with immunotoxic properties in a complex mixture of biologically active agents such as plant extracts. Subplantar injection (2 mg) of a crude aqueous-ethanolic extract from Ginkgo leaves caused a significant lymphoproliferative reaction (LPR) in the ipsilateral popliteal lymph node. PLNA-active compounds in this extract could be enriched in the lipophilic phase by liquid-liquid partition between heptane and water. Chemical analysis of the heptane extract revealed the presence of a high concentration of alkylphenols (approx. 30%) and further subfractionation indicated that the enlargement of the popliteal lymph node was mainly due to the content of ginkgolic acids. This presumption was corroborated by observing a similar LPR following injection of a purified mixture of ginkgolic or hydroginkgolic acids. Thus, our experiments confirm that Ginkgo leaf extracts may contain constituents with immunotoxic properties, underlining the need to apply adequate production procedures to guarantee the completest possible removal of these compounds. The PLNA appears to represent a simple test model for the detection, characterisation and control of ingredients with potential immunotoxic side effects in complex herbal drugs.

Heart rate variability in dilated cardiomyopathy

Chronic heart failure is associated with excessive neurohormonal activation. Analysis of heart rate variability is considered a valid technique for assessment of the autonomic balance of the heart. Twenty symptomatic patients of dilated cardiomyopathy in NYHA class II-IV symptomatic status and as many normal controls were subjected to 24 hours Holter monitoring to assess the heart rate variability with both time domain and frequency domain analysis. Age of the patients ranged from 12 to 67 years (mean +/- SD 38.6 +/- 7 years), the male-female ratio was 4:1. The left ventricular ejection fraction of the patients was between 18-42 percent (mean +/- SD 30.2 +/- 9%) and all received diuretics, digoxin and angiotensin-converting enzyme inhibitors. Heart rate variability parameters measured included mean heart rate with standard deviation, hourly heart rate with SD and the mean of all normal RR intervals from the 24-hour recording. Time domain measures calculated were SD of all normal RR intervals, SD of 5 minute mean RR intervals and root mean square of difference of successive RR intervals. Using spectral plots, frequency domain subsets of low frequency and high frequency were analysed and expressed in normalised units. Total power was also measured. In the dilated cardiomyopathy patients, mean 24-hour heart rate in beats per minute was significantly higher in comparison to controls (82 +/- 13 vs 72 +/- 8; p < 0.001) whereas mean hourly heart rate with standard deviation (msec) was significantly lower (97 +/- 41 vs 232 +/- 25; p < 0.001), SD of all normal RR intervals (msec) was 85.5 +/- 26.3 vs 139.4 +/- 16.9 in controls (p < 0.001), SD of 5 minute mean RR intervals (msec) was also significantly less in patients in comparison to controls (75.8 +/- 39.6 vs 130.8 +/- 20.3; p < 0.001). However, although root mean square of difference of successive RR intervals (msec) was reduced in patients (30.1 +/- 9.3 vs 37.3 +/- 11.7; p < 0.05), the difference was non-significant. Low frequency power (0.05-0.15 Hz) (normalised units) was reduced in the dilated cardiomyopathy group (0.0721 +/- 0.003 vs 0.136 +/- 0.047 in the control group; p < 0.001). High frequency power (0.35-0.50 Hz) (normalised units) (0.08 +/- 0.05 in patients vs 0.09 +/- 0.02 in controls; p > 0.1) and total power frequency (0.02-0.50 Hz) (normalised units) (0.34 +/- 0.05 in patients vs 0.35 +/- 0.12 in controls; p > 0.1) was non-significantly different in the two groups. Regression analysis showed a significant decrease in SD of all normal RR intervals, SD of 5 minute mean RR intervals, low frequency, high frequency, total power and a non-significant decrease in root mean square of difference of successive RR intervals with a decrease in ejection fraction percent whereas there was a significant decrease in SD of all normal RR intervals, SD of 5 minute mean RR intervals, low frequency and total power and a less significant decrease in root mean square of difference of successive RR intervals and high frequency power with an increase in NYHA class. At 6 months duration, 6 patients were lost to follow-up, 3 patients were readmitted (2 for congestive cardiac failure, one of paroxysmal supraventricular tachycardia). One patient who was NYHA class IV at baseline was readmitted for congestive cardiac failure and showed much lower heart rate variability parameters compared to the average of the patients. We conclude that in symptomatic dilated cardiomyopathy patients, heart rate variability parameters are significantly reduced in comparison to control subjects.

Damaged neuronal energy metabolism and behavior are improved by Ginkgo biloba extract (EGb 761)

The standardized extract EGb 761 from the dried green leaves of Ginkgo biloba is a complex mixture of ingredients with an uniquely broad spectrum of pharmacological activities on the central nervous system e.g. in memory enhancing properties and in the regulation of cerebral glucose/energy metabolism. To test these effects on both behavioral and metabolic brain parameters, the animal model of intracerebroventricular (i.c.v.) streptozotocin (STZ) treatment was used. To quantify the experimental data more precisely, animals that were good performers were separated from poor performers by means of the holeboard test before i.c.v. administration of STZ. Good performers only were considered for the study. After a 1-week training period on the holeboard improvement was seen in all animals in learning, memory and cognition, and the improvement was maintained over the investigation period of 12 weeks in the control group. In this group, the energy pool in the cerebral parietotemporal cortex was found to be large and the energy turnover high. After triplicate i.c.v. STZ injection, working memory (WM), reference memory (RM), and passive avoidance (PA) behavior fell off and continued to deteriorate throughout the investigation period. Otherwise there were no significant differences in locomotor activity, excluding the possibility that activity per se might have contributed to the behavioral abnormalities. These were accompanied by a permanent deficit in cerebral energy metabolism. The ongoing deterioration in behavior and the maintained deficit in cerebral energy metabolism occurring after a triplicate i.c.v. STZ injection were significantly slowed down by EGb761. The deficits in learning, memory and cognition were partially compensated, and the disturbances in cerebral energy metabolism returned to almost completely normal values. These findings underscore the beneficial effect of EGb761 that had been reported in dementia disorders.

Bilobalide, a constituent of Ginkgo biloba, inhibits NMDA-induced phospholipase A2 activation and phospholipid breakdown in rat hippocampus

In rat hippocampal slices superfused with magnesium-free buffer, glutamate (1 mM) caused the release of large amounts of choline due to phospholipid breakdown. This phenomenon was mimicked by N-methyl-D-aspartate (NMDA) in a calcium-sensitive manner and was blocked by NMDA receptor antagonists such as MK-801 and 7-chlorokynurenate. The NMDA-induced release of choline was not caused by activation of phospholipase D but was mediated by phospholipase A2 (PLA2) activation as the release of choline was accompanied by the formation of lyso-phosphatidylcholine (lyso-PC) and glycerophospho-choline (GPCh) and was blocked by 5-[2-(2-carboxyethyl)-4-dodecanoyl-3,5-dimethylpyrrol-1-yl]pentano ic acid, a PLA2 inhibitor. Bilobalide, a constituent of Ginkgo biloba, inhibited the NMDA-induced efflux of choline with an IC50 value of 2.3 microM and also prevented the formation of lyso-PC and GPCh. NMDA also caused a release of choline in vivo when infused into the hippocampus of freely moving rats by retrograde dialysis. Again, the effect was completely inhibited by bilobalide which was administered systemically (20 mg/kg i.p.). Interestingly, convulsions which were observed in the NMDA-treated rats were almost totally suppressed by bilobalide. We conclude that release of choline is a sensitive marker for NMDA-induced phospholipase A2 activation and phospholipid breakdown. Bilobalide inhibited the glutamatergic excitotoxic membrane breakdown both in vitro and in vivo, an effect which may be beneficial in the treatment of brain hypoxia and/or neuronal hyperactivity.

Acute effect of KA-672, a putative cognitive enhancer, on neurotransmitter receptor binding in mouse brain

7-Methoxy-6-[3-[4-(2-methoxyphenyl)piperazin-1-yl]propoxy]-3,4-dim ethyl-2H-1-benzopyran-2-one hydro-chloride (KA-672), structurally related to naturally occurring coumarins, has been described as a potential drug for enhancing cognitive functions. However, a detailed characterization of the pharmacological profile of KA-672 in vivo is still lacking. Quantitative neurotransmitter receptor autoradiography was used as a tool to screen for KA-672-induced changes in a number of transmitter receptors including cholinergic, noradrenergic, glutamatergic, GABAergic, and serotonergic subtypes throughout the brain. Two hours following treatment of mice with 1 mg/kg KA-672 per os, slight increases of nicotinic and M1-muscarinic cholinergic receptor binding, of alpha2-and beta-adrenoceptor as well as 5-HT1A receptors in various cerebral cortical regions were observed, whereas 5-HT2A binding sites were strikingly increased throughout the brain following KA-672 treatment. In contrast, (+/-)-alphaamino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor binding was significantly decreased in some cortical regions after drug treatment. No effects of KA-672 treatment on N-methyl-D-aspartate, kainate, GABA(A) and benzodiazepine receptor as well as M2-muscarinic cholinergic and high-affinity choline uptake binding were observed. As interactions between the cholinergic, noradrenergic and serotonergic neurotransmission have been stressed to play important roles in realizing learning and memory events, the cognition-enhancing effects of KA-672 may be due to this complex in vivo pharmacological profile of KA-672.

KA-672 inhibits rat brain acetylcholinesterase in vitro but not in vivo

KA-672, a lipophilic benzopyranone derivative which is currently under development as a cognitive enhancer and antidementia drug, has previously been shown to have facilitatory effects on learning and memory in rats at doses of 0.1-1 mg/kg. We now report that KA-672 inhibited the activity of acetylcholinesterase (AChE), measured in vitro in rat brain cortical homogenate, with an IC50 value of 0.36 microM indicating that KA-672 may improve cognitive functions as a consequence of AChE inhibition. However, when we employed the microdialysis procedure to monitor acetylcholine (ACh) release from rat hippocampus, no effect of KA-672 (0.1-10 mg/kg) was found, indicating a lack of inhibition of brain AChE under in vivo-conditions. [14C]-labelled KA-672 was found to easily penetrate the blood-brain barrier, and an apparent concentration of 0.22 nmol/g brain (equivalent to 0.39 microM tissue concentration) was calculated following an i.p. injection of 1 mg/kg KA-672. However, no labelled substance could be detected in hippocampal microdialysates or in cerebrospinal fluid (CSF) taken from the cisterna magna, indicating that the concentration of KA-672 in brain extracellular fluid must have been below 0.01 microM. We conclude that KA-672 is a potent AChE inhibitor, an activity which, however, does not contribute to its behavioural effects in vivo because the lipophilic drug does not reach sufficient concentrations in the extracellular fluid, apparently due to cellular sequestration.

Hyperforin enhances the extracellular concentrations of catecholamines, serotonin and glutamate in the rat locus coeruleus

Hyperforin is the main antidepressant component of hypericum perforatum (St. John's Wort). Using the push-pull superfusion technique we tested whether hyperforin influences extracellular concentrations of neurotransmitters in the rat locus coeruleus. Hyperforin (10 mg/kg, i.p.) not only enhanced the extracellular levels of the monoamines dopamine, noradrenaline and serotonin, but also that of the excitatory amino acid glutamate. The levels of the main serotonin metabolite 5-hydroxyindolacetic acid, as well as those of the amino acids GABA, taurine, aspartate, serine and arginine, were not influenced. Together with in vitro studies, our findings suggest that the antidepressant property of hyperforin is due to enhanced concentrations of monoamines and glutamate in the synaptic cleft, probably as a consequence of uptake inhibition.

The putative cognitive enhancer KA-672.HCl is an uncompetitive voltage-dependent NMDA receptor antagonist

KA-672.HCl (KA-672) is a new substance demonstrating anti-dementia properties. It shows modulatory effects on several neurotransmitter systems known to be affected in patients with Alzheimer's disease. In this study the action of KA-672 on the NMDA receptors was examined by applying patch clamp techniques to acutely isolated hippocampal neurons. KA-672 antagonizes NMDA responses in a voltage-dependent manner. At a holding potential of -90 mV the IC50 value for the blocking action of KA-672 was 20+/-7 microM. This action of KA-672 is independent on the concentration either of agonist or coagonist of NMDA receptor. Ketamine, which interacts with the PCP center, does not occlude the action of KA-672. Evidently, KA-672.HCl is a weak NMDA receptor-operated channel blocker. This property may account for its pharmacological profile.

Hyperforin as a possible antidepressant component of hypericum extracts

We demonstrate that the phloroglucinol derivative hyperforin is not only the major lipophilic chemical constituent of the medicinal plant Hypericum perforatum (St. John's wort) but also a potent uptake inhibitor of serotonin (5-HT), dopamine (DA), noradrenaline (NA), GABA and L-Glutamate with IC50 values of about 0.05-0.10 microg/ml (5-HT, NA, DA, GABA) and about 0.5 microg/ml (L-glutamate) in synaptosomal preparations. Furthermore, potencies of two different hypericum extracts in two conventional pharmacological paradigms useful for the detection of antidepressants (behavioral despair, learned helplessness), closely correlate with their hyperforin contents. In addition, most till now known neuropharmacological properties of the clinically used hypericum extracts can also be demonstrated with pure hyperforin. It appears, therefore, that this non-nitrogenous constituent is a possible major active principle responsible for the observed clinical efficacies of the extract as an antidepressant and that it could also be a starting point for drug discovery projects engaged in the search of psychoactive drugs with novel mode of action.

Antidepressant activity of hypericum perforatum and hyperforin: the neglected possibility

Efforts leading to the identification of hyperforin as an antidepressive component of therapeutically used alcoholic hypericum extracts are described and discussed. Initially, the effects of this unique and major constituent of the herb were detected in peripheral organs using in vitro models and an extract was obtained by supercritical extraction of the herb by carbon dioxide. These extracts are highly enriched in hyperforin (38.8%) and are devoid of hypericines and numerous other components of alcoholic extracts. Studies with such an extract and with isolated hyperforin indicated that this acylphloroglucinol derivative can inhibit serotonin-induced responses and uptake of this neurotransmitter in peritoneal cells. Assuming that the effects of hyperforin were due to its actions on serotoninergic 5-HT3/5-HT4 receptors, further studies were conducted to investigate its effects on the CNS. These efforts revealed its antidepressant activity in the behavioral despair test and led to the working hypothesis that hyperforin and serotoninergic mechanisms are involved in the antidepressant activities of alcoholic hypericum extracts. The observations made during this study also indicate that hyperforin is the major, but not the only antidepressive component of alcoholic extracts.

Oral bioavailability of hyperforin from hypericum extracts in rats and human volunteers

Validated analytical methods suitable for determining hyperforin in plasma after administration of alcoholic Hypericum perforatum extracts containing hyperforin are described. After oral administration of 300 mg/kg Hypericum extract (WS 5572, containing 5% hyperforin) to rats maximum plasma levels of approximately 370 ng/ml (approx. 690 nM) were reached after 3 h, as quantified by a HPLC and UV detection method. Estimated half-life and clearance values were 6 h and 70 ml/min/kg respectively. Since therapeutic doses of Hypericum extracts are much lower than that used in rats, a more sensitive LC/MS/MS method was developed. The lower limit of quantification of this method was 1 ng/ml. Using this method, plasma levels of hyperforin could be followed for up to 24 h in healthy volunteers after administration of film coated tablets containing 300 mg hypericum extracts representing 14.8 mg hyperforin. The maximum plasma levels of approximately 150 ng/ml (approx. 280 nM) were reached 3.5 h after administration. Half-life and mean residence time were 9 and 12 h respectively. Hyperforin pharmacokinetics were linear up to 600 mg of the extract. Increasing the doses to 900 or 1200 mg of extract resulted in lower Cmax and AUC values than those expected from linear extrapolation of data from lower doses. Plasma concentration curves in volunteers fitted well in an open two-compartment model. In a repeated dose study, no accumulation of hyperforin in plasma was observed. Using the observed AUC values from the repeated dose study, the estimated steady state plasma concentrations of hyperforin after 3 x 300 mg/day of the extract, i.e., after normal therapeutic dose regimen, was approximately 100 ng/ml (approx. 180 nM).

Activity profiles of two hyperforin-containing hypericum extracts in behavioral models

The behavioral activity profile of a therapeutically used alcoholic hypericum extract containing hyperforin (4.5%) in rodent models was compared with that of an experimental CO2 extract devoid of hypericines but highly enriched in hyperforin (38.8%). The antidepressant activities of 50, 150 and 300 mg/ kg/day of the alcoholic extract were similar to those of 5, 15 and 30 mg/kg/day respectively of the CO2 extract. The ethanol extract in the same dose range potentiated dopaminergic behavioral responses, whereas these effects were either absent or less pronounced in the CO2 extract treated groups. By contrast, serotoninergic effects of the CO2 extract were more pronounced than those of the alcoholic extract. These and various other observations made during the study confirm that although the antidepressant action of hypericum extracts depends on their hyperforin contents, their spectrums of central activity are due to other component(s). Our working hypothesis that hyperforin and serotoninergic mechanisms are involved in the therapeutically observed antidepressant activities of hypericum extracts is in agreement with these observations.

[In vitro and in vivo studies on the cardioprotective action of oligomeric procyanidins in a Crataegus extract of leaves and blooms]

Cardioprotective effects of a standardized extract from leaves with flowers of Crataegus (WS-1442; content of oligomeric procyandins [OPC]: 18.75%) have recently been demonstrated in an ischemia-reperfusion model in rats. Further studies were now conducted to clarify the mechanism of action and to identify active constituents involved in these effects of WS-1442. Exhausting partitioning between ethyl acetate/water and successive ultrafiltration of the aqueous layer led to the quantitative recovery of three fractions, which were tested for their in vitro radical scavenging (RS) and human neutrophil elastase (HNE) inhibitory activity. The lipophilic ethylacetate-soluble fraction A, enriched in flavone derivatives and constituting 14.9% of WS-1442, was as active as WS-1442 in inhibiting HNE. However, its RS activity was only about half that of the primary extract. Although 67.9% of WS-1442 was recovered in a water-soluble low molecular weight fraction B, this fraction displayed only weak RS and HNE inhibiting activity. In contrast, the RS and HNE inhibiting potencies of an essentially flavone-free and OPC-rich fraction C (21.3% of WS-1442) were significantly higher (inhibition of lipid peroxidation: IC50 0.3 microgram/ml; inhibition of HNE: IC50 0.84 microgram/ml) as those of WS-1442. The RS and HNE inhibitory activities of the extract and those of its fractions correlated well with their OPC-content but not with their concentration of flavonols. These results demonstrate that OPCs of Crataegus extracts possess stronger radical scavenging activities than flavone derivatives or other constituents. In addition, the oligomeric components are potent inhibitors of HNE. Oral administration of 20 mg/kg/d of the OPC-rich fraction C to rats afforded similar protection against ischemia-reperfusion induced pathologies as treatment with WS-1442 at a dose of 100 mg/kg/d. These observations indicate that radical scavenging and elastase inhibitory activities could indeed be involved in the observed cardioprotective effects of WS-1442, and demonstrate that OPCs are major orally active constituents of WS-1442. Thus, Crataegus extracts used therapeutically for cardiovascular diseases should be analyzed and standardized for their OPC-content.

Phospholipid breakdown and choline release under hypoxic conditions: inhibition by bilobalide, a constituent of Ginkgo biloba

A marked increase of choline release from rat hippocampal slices was observed when the slices were superfused with oxygen-free buffer, indicating hypoxia-induced hydrolysis of choline-containing phospholipids. This increase of choline release was suppressed by bilobalide, an ingredient of Ginkgo biloba, but not by a mixture of ginkgolides. The EC50 value for bilobalide was 0.38 microM. In ex vivo experiments, bilobalide also inhibited hypoxia-induced choline release when given p.o. in doses of 2-20 mg/kg 1 h prior to slice preparation. The half-maximum effect was observed with 6 mg/kg bilobalide. A similar effect was noted after p.o. administration of 200 mg/kg EGb 761, a ginkgo extract containing approximately 3% of bilobalide. We conclude that ginkgo extracts can suppress hypoxia-induced membrane breakdown in the brain, and that bilobalide is the active constituent for this effect.

Follow-up results of balloon angioplasty for native coarctation of aorta

Balloon angioplasty of native discrete (< 1 cm) coarctation of thoracic aorta was performed in 29 patients [aged 13 to 31 years (mean 21.5 +/- 5.8 years), 22 males and 7 females], from March 1993 to December 1995. The patients were followed up for two years. After angioplasty, peak systolic arterial pressure (PSAP) decreased from 173.5 +/- 18.1 mm Hg to 122.5 +/- 9.9 mm Hg (p < 0.001), peak systolic pressure gradient (PSG) decreased by 90.9 percent from 86.2 +/- 15.77 to 7.77 +/- 3.8 mm Hg (p < 0.001) and the coarcted segment diameter increased about three times from 3.7 +/- 1.6 to 10.9 +/- 3.3 mm (p < 0.001). PSG decreased to < 10 mm Hg in 27 patients (93%) whereas in the other two patients PSG was 17 and 13 mm Hg. Restenosis appeared in 2 patients (6.8%); aneurysm in one patient (3.4%) which remained static even after 1.3 years of follow-up; mild dissection in 3 patients (10.3%); temporary femoral artery occlusion in 2 (6.8%) patients who recovered with heparin injection. Though hypertension disappeared after balloon dilatation in all patients, it reappeared in 3 patients (10.3%) within 7 days and in 10 patients (34.5%) within 6 months. In conclusion, balloon angioplasty of CoA is a good alternative to surgical correction.

Studies on prosthetic valve function--a transesophageal echocardiographic assessment

Haemodynamic assessment was done by colour flow mapping and Doppler interrogation by both Transthoracic (TTE) and Transesophageal echocardiography (TEE) in 40 consecutive patients (mean age 36.6 +/- 12.35 years) with prosthetic valves. There were 30 cases of mitral (MVR) and 12 aortic (AVR) valve replacement. Major purpose of the study was to detect the sensitivity of TEE in detecting prosthetic valve malfunction particularly in comparison to TTE. Pannus was detected in 3 and 8 cases of MVR (p < 0.01) by TTE and TEE respectively; however, TEE was found to be of equal status in detecting pannus over AV (2 cases). Physiological regurgitation in MVR and AVR was detected in 13% and 25% by TTE and 20% and 33% by TEE respectively. Paravalvular leak was detected in 3 cases of MVR by TEE compared to only case by TTE. Though it is difficult to deduce any specific conclusion from this small number of patients, there is definite trend to higher sensitivity in detecting disorders with TEE specially for mitral prostheses.

Low-dose amiodarone in severe chronic heart failure

Sudden cardiac death is a common cause of mortality in patients with congestive heart failure. Asymptomatic ventricular arrhythmia has been attributed as the cause for increased overall mortality in such patients. We conducted a prospective randomised single-blind placebo-controlled trial with low-dose amiodarone to assess its efficacy in reducing mortality in severe congestive heart failure and its effect on exercise tolerance, left ventricular systolic function and ventricular ectopic activity. Patients were randomised to receive amiodarone (n = 36) 400 mg/day orally for one month followed by a maintenance dose of 200 mg/day, or to a standard treatment (n = 40) according to intention-to-treat principle. There were 10 cardiac deaths in the amiodarone-treated group and 16 in the control group. Significant improvement was noted in exercise time in the treadmill test (modified Bruce Protocol) among patients in the amiodarone-treated group while no such statistical difference was detectable in the placebo group. Side-effects in the amiodarone group included asymptomatic rise in hepatic enzymes (three-fold) in 6 percent and proarrhythmia in 3 percent of patients. Nausea was reported in one patient and rash in one. Though low-dose amiodarone proved to be an effective antiarrhythmic agent, it failed to live up to the expectation of improving sudden cardiac death in patients with severe chronic heart failure and asymptomatic ventricular ectopy.