A reversed phase high performance liquid chromatography method for the analysis of boswellic acids in Boswellia serrata

An HPLC method for the separation of boswellic acids, the active constituents in Boswellia serrata resin has been developed. The first accurate determination of 6 individual acids was possible in the resin as well as in multi-component preparations. By using an acidic mobile phase, raised temperature and a 4 microm Synergi MAX-RP 80 A column the acids could be detected at levels as low as 0.9 microg/ml. The study of market products revealed significant variations in the content of these pharmacologically active compounds in commercial samples.

A new lignan glycoside from Eleutherococcus senticosus

A new lignan glycoside, named eleutheroside E(2) (1), has been isolated from the roots of Eleutherococcus senticosus (known as "Siberian ginseng"), along with isomaltol 3-O-alpha-D-glucopyranoside (2), eleutherosides B, E and E(1), and thymidine. The structure of 1 was established by spectral interpretations as episyringaresinol 4"-O-beta-D-glucopyranoside. Compound 2 is described here for the first time as a naturally occurring compound.

Effect of acute myocardial infarction on cholesterol ratios

OBJECTIVE

In patients with acute myocardial infarctions (MIs), cholesterol levels are no longer valid after 24 h from presentation because acute MI causes a rapid decline in serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol. The objective of this study was to evaluate the effect of acute MI on the total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL cholesterol ratio.

METHODS

The study consisted of 45 patients who were admitted to the hospital with acute MIs. Serum levels of total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides were determined on day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL cholesterol ratio were calculated. Serum lipid levels and cholesterol ratios were compared between day 1 post-MI and day 4 post-MI.

RESULTS

From day 1 post-MI to day 4 post-MI, the mean (+/- SD) serum levels of total cholesterol (188.4 +/- 52.5 vs. 170.5 +/- 57.2 mg/dL, respectively; p = 0.01), LDL cholesterol (120.3 +/- 48.9 vs. 105.9 +/- 43.0 mg/dL, respectively; p = 0.009), and HDL cholesterol (45.0 +/- 18.5 vs 39.3 +/- 16.1 mg/dL, respectively; p < 0.001) decreased, but the mean serum level of triglycerides (119.2 +/- 81.2 vs 149.3 +/- 68.3 mg/dL, respectively; p = 0.006) increased. The cholesterol ratios, however, remained unchanged between day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol ratio was 4.59 +/- 1.84 on day 1 post-MI and 4.67 +/- 1.77 on day 4 post-MI (change not significant). The LDL cholesterol/HDL cholesterol ratio was 2.96 +/- 1.58 on day 1 post-MI and 2.99 +/- 1.44 on day 4 post-MI (change not significant).

CONCLUSION

Acute MI does not affect the cholesterol ratios. Therefore, when the absolute levels of serum cholesterol are no longer valid (beyond 24 h after an MI), the cholesterol ratios still could be useful for cholesterol risk assessment in patients with acute MIs.

Separation and quantification of the major daucane esters of Ferula hermonis by HPLC

A simple HPLC method was developed to quantify the major daucane sesquiterpene esters present in herb and roots of Ferula hermonis Boiss. The method utilized a C(18) reversed phase analytical column with isocratic elution for 30 minutes and UV detection at 240 nm. Extracts from two crude plant samples and two commercial products were fingerprinted and quantitatively analyzed.

Prognostic value of serum cardiac troponin I in ambulatory patients with chronic renal failure undergoing long-term hemodialysis: a two-year outcome analysis

OBJECTIVES

We sought to evaluate the prognostic value of cardiac troponin I (cTnI) in asymptomatic, ambulatory patients with chronic renal failure treated with long-term hemodialysis.

BACKGROUND

Smaller, short-term follow-up studies on this subject have given conflicting results.

METHODS

A total of 126 ambulatory patients with chronic renal failure treated with long-term hemodialysis were followed for two years for all-cause mortality, cardiac mortality, all-cause hospital admissions and cardiac hospital admissions. Serum cTnI was measured before dialysis at the time of study entry.

RESULTS

One hundred two patients had normal serum levels of cTnI (< or =0.03 ng/ml) and 24 patients had elevated levels (0.015 +/- 0.007 vs. 0.053 +/- 0.029 ng/ml, p < 0.0001). No significant difference in all-cause mortality (20 vs. 4 deaths), cardiac mortality (4 vs. 1 death), all-cause hospital admissions (1.74 +/- 1.72 vs. 1.25 +/- 1.19 admissions/patient) or cardiac admissions (0.52 +/- 0.89 vs. 0.33 +/- 0.76 admissions/patient) was present between the patients with normal cTnI levels and those with elevated cTnI levels. Serum cTnI was not significantly different between patients who died versus those who survived (0.022 +/- 0.019 vs. 0.022 +/- 0.021 ng/ml). Serum cTnI was not an independent predictor of all-cause mortality, cardiac mortality, all-cause admissions or cardiac admissions. Age (older) and serum albumin (lower) were independent predictors of all-cause mortality, whereas a history of myocardial infarction was an independent predictor of cardiac mortality. Serum sodium (lower) was an independent predictor of all-cause hospital admissions, whereas hypertension and previous myocardial infarction were independent predictors of cardiac admissions. The best predictors of the time to death were age (older) and serum sodium level (lower), irrespective of the serum cTnI levels.

CONCLUSIONS

Cardiac troponin I has a limited role in predicting mortality and hospital admissions in asymptomatic patients with chronic renal failure treated with long-term hemodialysis.

Antimalarial (+)-trans-hexahydrodibenzopyran derivatives from Machaerium multiflorum

Bioassay-guided fractionation of Machaerium multiflorum yielded the hitherto unreported (+)-trans-hexahydrodibenzopyrans machaeriol A (1) and machaeriol B (2), as well as the known guaiane sesquiterpene (-)-kessane. Structure elucidation was based on (1)H and (13)C NMR data, mainly 2D NMR (1)H-(1)H COSY, (1)H-(13)C HMQC, (1)H-(13)C HMBC, and (1)H-(1)H NOESY experiments. This is the first report of the hexahydrodibenzopyrans from a higher plant other than the genus Cannabis. The cannabimimetic activity was thus evaluated by radioligand binding assay for cannabinoid receptor CB1, which indicated, notably, that both 1 and 2 were inactive. In addition, the cross reactivity of 1 and 2 toward antibodies designed for urinary metabolites of cannabinoids was evaluated with the EMIT and On Line cannabinoids assays. Both compounds showed no response at 100 000 ng/mL in both assays. Machaeriol B (2) demonstrated in vitro antimalarial activity (IC(50) = 120 ng/mL) against Plasmodium falciparum W-2 clone.

Analysis of terpenelactones in Ginkgo biloba by high performance liquid chromatography and evaporative light scattering detection

A reversed phase HPLC method permitting the determination of 5 terpenelactones in Ginkgo biloba, without the need of any sample preparation is presented in this paper. The compounds were successfully separated within 25 min by using a C-12 column, an evaporative light scattering (ELS) detector and a mobile phase comprising of ammonium acetate buffer, methanol and isobutanol. All terpenelactones were detectable at concentrations as low as 20.3 microg/ml. The analysis of G. biloba market products showed remarkable variations in the lactone content, and more than 2 fold differences in the suggested daily doses of the total lactones, from 8.84 mg to 18.28 mg, respectively.

Diagnostic and prognostic value of Holter-detected ST-segment deviation in unselected patients with chest pain referred for coronary angiography: a long-term follow-up analysis

OBJECTIVE

To evaluate the diagnostic and prognostic significance of ST-segment deviation detected by ambulatory Holter monitoring in unselected chest pain patients referred for coronary angiography.

METHODS

Two hundred seventy-seven patients (71% were men) who underwent coronary angiography for evaluation of chest pain were studied with 24-h ambulatory Holter monitoring within 72 h of angiography. A lumen diameter reduction of > or = 50% was considered coronary artery disease. The ST-segment deviation was defined as > or = 1-mm deviation from the baseline lasting > or = 1 min separated by a minimum of 1 min. The patients were followed up for 65 +/- 21 months (mean +/- SD) for occurrences of death, myocardial infarction, hospitalization for unstable angina, and need for revascularization.

RESULTS

Of the 277 patients, 223 (80%) had coronary artery disease. The prevalence of coronary artery disease was not significantly different in patients with (43 of 48 patients; 90%) and without (180 of 229 patients; 79%) Holter-detected ST-segment deviation. The diagnostic accuracy of Holter-detected ST-segment deviation in predicting the presence of coronary artery disease was poor (33%), with a sensitivity of 19% and a specificity of 91%. The presence of Holter-detected ST-segment deviation was not predictive of future cardiac events or death.

CONCLUSION

The ST-segment changes detected on ambulatory Holter monitoring are of limited value in identifying coronary artery disease and predicting the future adverse cardiac events or death in unselected patients with chest pain.

Detection of disulfide bonds in bovine brain tubulin and their role in protein folding and microtubule assembly in vitro: a novel disulfide detection approach

Cysteine residues in tubulin are actively involved in regulating ligand interactions and microtubule formation both in vivo and in vitro. These cysteine residues are sensitive reporters in determining the conformation of tubulin. Although some of the cysteines are critical in modulating drug binding and microtubule assembly, it is not clear how many of these normally exist as disulfides. The controversy regarding the disulfide bonds led us to develop a disulfide detection assay to reexamine the presence of the disulfide linkages in purified alphabeta tubulin and explore their possible biological functions in vitro. The accessible cysteine residues in alphabeta tubulin were alkylated with an excess of iodoacetamide to prevent artifactual generation of disulfide linkages in tubulin. After removal of excess iodoacetamide, tubulin was unfolded in 8 M urea. Half of the unfolded tubulin was treated with dithiothreitol to reduce any disulfide bonds present. The aliquots were then treated with iodo[(14)C]acetamide and the incorporation of radioactivity was measured. We also used the same approach to detect the disulfide linkages in the tubulin in a whole-cell extract. We found in both cases that the samples which were not treated with dithiothreitol had little or no incorporation of iodo[(14)C]acetamide, while the others that were treated with dithiothreitol had significant amounts of (14)C incorporation into tubulin. Moreover, the reduction of the disulfide linkages in tubulin resulted in inhibition of microtubule assembly (29-54%) and markedly affected refolding of the tubulin from both an intermediate and a completely unfolded state. All these data therefore suggest that tubulin has intrachain disulfide bonds in the alpha- and beta-subunits and that these disulfides assist in correct refolding of tubulin from the intermediate unfolded state or help to recover the hydrophobic domains from the completely unfolded state. These disulfides also regulate microtubule assembly and the stability of tubulin in vitro. Our results suggest that tubulin disulfides may play a role in tubulin folding and that thiol-disulfide exchange in tubulin could be a key regulator in microtubule assembly and dynamics of tubulin in vivo.

Effects of phosphorothionate on the reproductive system of male rats

Acute and Sub-acute toxic effects of a new pesticide phosphorothionate coded as RPR-V on testis of albino rat were studied. For the acute study, rats received a single dose of 30 mg/kg of RPR-V and sacrificed after 24 hours. For the Subacute study, 1.42 mg/kg/day was administered orally to rats for 10 days and 21 days. Acute exposure of rats to RPR-V brought no change either in the Gonadosomatic Index (GSI) or in the structure of testis or in the serum levels of Testosterone. Similarly, no significant change was observed in the Glutathione S-transferase (GST) activity. But, in testis there was significant increased in the reduced Glutathione (GSH) and Acid Phosphatase (AcP), whereas Alkaline Phosphatase (AkP) levels decreased significantly at 24hr post treatment. On 7th day (withdrawal period) after the cessation of the treatment the GSH, AcP, and AkP levels reached to near control. The sub-acute study revealed a significant post treatment. Due to RPR-V treatment the testis AcP levels increased significantly at 21st day of medication but AkP levels decreased both at 10th and 21st day of post treatment. Histopathological studies showed that after 10th day testis showed considerable loss of spermatozoids and at 21st day complete derangement of cellular organization was observed. Testosterone levels decreased significantly after 10th day and remained significantly low at 21st day. However, withdrawal studies showed a recovery in testis of rat treated with RPR-V. GST, GSH, GSI, AcP and AkP values were recovered, testosterone levels were also recovered but recovery in testis structure remained at a low profile.

Atrial fibrillation associated with systemic lupus erythematosus and use of methylprednisolone

Systemic lupus erythematosus is known to have cardiac manifestations consisting of pericarditis, myocarditis, endocarditis, and coronary vasculitis. Pericarditis is the most common cardiac manifestation of systemic lupus erythematosus. Myocarditis may be suspected in patients presenting with unexplained tachycardia, conduction disturbances, unexplained systolic dysfunction with or without heart failure, or arrhythmias. The development of arrhythmias in systemic lupus erythematosus could be secondary to pericarditis, myocarditis, or ischemia caused by coronary vasculitis. The development of atrial fibrillation in systemic lupus erythematosus is not commonly reported. There have been few reports on the patients developing atrial fibrillation after being started on methylprednisolone therapy. Described here is a case of the development of atrial fibrillation in a newly diagnosed 37-year-old patient with systemic lupus erythematosus who was started on intravenous methylprednisolone therapy.

Improved method for the determination of oxindole alkaloids in Uncaria tomentosa by high performance liquid chromatography

This Paper describes an improved HPLC method for the determination of pentacyclic oxindole alkaloids in Uncaria tomentosa (Cat's Claw). Six of the isomeric compounds could be baseline separated at room temperature within less than 30 min by using 3 microm C-18 column material and a mobile phase consisting of 10 mM phosphate buffer at pH 7.0 and acetonitrile. At a wavelength of 245 nm all standard compounds could be detected at concentrations as low as 0.63 microg/ml. Different samples of U. tomentosa bark and market products containing Cat's Claw were extracted with a modified procedure ensuring the integrity of the alkaloids and analyzed successfully. The results indicated accuracy and consistency of the new method, and showed variations in the total alkaloid content in products from 0.156 to 0.962%.

An improved method for the determination of betaine in Echinacea products

A rapid and sensitive HPLC method for the separation and quantification of betaine in Echinacea products has been developed. Strong cation-exchange (SCX) material was used as stationary phase, and a mixture of methanol and 50 mM choline buffer (pH 3.5) as mobile phase. After formation of the bromophenacyl derivative, betaine was detected at 254 nm with a detection limit of 0.2 microgram/ml. The method was successfully used to analyze several Echinacea market products, and significant variations in their betaine content from 0.04 to 0.64% were observed.

High-performance liquid chromatography determination of hydrastine and berberine in dietary supplements containing goldenseal

Goldenseal (Hydrastis canadensis L., Ranunculaceae) is an ingredient of various dietary supplements intended for enhancing general body immunity. Many goldenseal products are currently available in the United States, either alone or in combination with echinacea. In most products, the content of the main active alkaloids of goldenseal, hydrastine and berberine, is not indicated on the label. A high-performance liquid chromatography (HPLC) method has been developed for the detection and quantification of hydrastine and berberine in a number of products obtained from the United States market. The method uses a Phenomenex Luna C(18) column, a mobile phase consisting of solvent A (100 mM sodium acetate/acetic acid, pH 4.0) and solvent B (acetonitrile/methanol; 90/10, v/v). Elution was run at a flow rate of 1.0 mL/min, with a linear gradient of 80- 40% A in B over 20 min and ultraviolet detection at 290 nm. A wide range of content variation was observed for both alkaloids in the tested samples.

A cardiac evoked response algorithm providing automatic threshold tracking for continuous capture verification: a single-center prospective study

BACKGROUND

The AutoCapture algorithm as implemented in Regency and Microny pacemakers (Pacesetter Inc., Sylmar, CA, USA) provides beat-by-beat monitoring of capture based on proper detection of the evoked response, provides high output back-up pulse when loss of capture occurs, performs periodic threshold evaluations and acquires the capture threshold data in a time-based event counter for later retrieval. The safety and efficacy of this algorithm was prospectively evaluated at a tertiary care hospital of north India.

METHODS AND RESULTS

Fifty-four patients (38 males, mean age 66+/-13 years) received a ventricular pacemaker model Regency SC+ with low polarization bipolar lead for high-grade atrioventricular block (n=42) and sick sinus syndrome (n=12). Evoked response and polarization signal were assessed initially at 24 hours postimplant, and follow-up measurements were systematically conducted at week 1 and months 1, 3 and 6. Further evaluation of eligible patients was performed at 6-monthly intervals. Lead implantation parameters were optimum in all patients. At 6 months, the algorithm was functional in 51 patients. The pacing threshold increased to 0.89+/-0.36 V (p<0.001) in the first month and stabilized thereafter. Significant saving of energy was accomplished by a constant output safety margin of 0.3 V instead of the traditional 100%. While the evoked response signal remained stable throughout the study period, the potential signal increased significantly from 0.6+/-0.7 mV to 1.0+/-0.6 mV (p<0.001) in the first month and remained steady subsequently. Back-up pacing in the event of exit block was confirmed in all 25 patients who underwent a 24-hour Holter test. Based on the suggested sense margins, ventricular undersensing was observed in 7 (28%) patients, the majority of whom had competitive cardiac rhythms. An elderly patient with pneumonic illness succumbed to pulmonary embolism at 6 months.

CONCLUSIONS

This large single-center experience on AutoCapture demonstrates the success of this algorithm in low-energy ventricular pacing without compromising the patient's safety.

Age-related differences in the use of cardiac medications in patients with coronary artery disease

BACKGROUND

Benefits of aspirin and beta-blocker use in patients with coronary artery disease and angiotensin-converting enzyme (ACE) inhibitors in those with left ventricular systolic dysfunction are well documented in all age groups.

OBJECTIVE

To investigate whether aspirin, beta-blockers, and ACE inhibitors are equally used in geriatric (> or =65 years) versus younger (<65 years) patients with coronary artery disease.

SETTING

University-affiliated major academic hospital.

METHODS

Records of 402 patients with coronary artery disease were analyzed for use of aspirin, beta-blockers, and ACE inhibitors. One hundred thirty patients with contraindications to use of these agents were excluded.

RESULTS

Of 272 study patients, 85% were using aspirin and 71% beta-blockers. Among the patients with left ventricular systolic dysfunction, 79% were using ACE inhibitors. One hundred forty-seven patients were of geriatric age, whereas 125 were of younger age. No significant difference in the use of aspirin (82% versus 89%, P = 0.10), beta-blockers (71% versus 70%, P = 0.85), or ACE inhibitors (86% versus 69%, P = 0.13) was found between geriatric and younger patients. This lack of difference in use of cardiac medications between geriatric and younger patients persisted on gender-based subgroup analysis. On decade-of-age-based analysis, aspirin use was not equally distributed among all the decades of age (P < 0.005), but beta-blocker use was.

CONCLUSION

Results of this study demonstrate equal use of aspirin, beta-blockers, and ACE inhibitors in geriatric versus younger patients with coronary artery disease. Aspirin use was not equally distributed among all the decades of age.

Investigation of Uña De Gato I. 7-Deoxyloganic acid and 15N NMR spectroscopic studies on pentacyclic oxindole alkaloids from Uncaria tomentosa

The C-8-(S) isomer of deoxyloganic acid (7-deoxyloganic acid), together with beta-sitosteryl glucoside, five known stereoisomeric pentacyclic oxindole alkaloids and the tetracyclic oxindole isorhyncophylline, were isolated from the inner bark of Uncaria tomentosa. Structures of the isolated compounds were based on 1H and 13C NMR data, mainly 2D NMR experiments, including 1H-13C HMBC and 1H-1H NOESY correlation. Furthermore, the hitherto unreported 15N chemical shifts of the isomeric oxindole alkaloids, using 1H-15N HMBC experiments, were utilized to facilitate their characterization. Uncarine D showed weak cytotoxic activity against SK-MEL, KB, BT-549 and SK-OV-3 cell lines with IC(50) values between 30 and 40 microg/ml, while uncarine C exhibited weak cytotoxicity only against ovarian carcinoma (IC(50) at 37 microg/ml).

Cocaine-induced torsades de pointes in idiopathic long Q-T syndrome

Torsades de pointes is a ventricular tachycardia characterized by the QRS complexes of changing amplitude that appear to twist around an isoelectric line. It usually precipitates in the setting of underlying Q-T interval prolongation, which has both congenital and acquired causes. The common acquired causes of torsades precipitation are medications, electrolyte imbalance, and severe bradycardia. This report presents a case of torsades de pointes that was precipitated by substance abuse in a patient with idiopathic long Q-T syndrome and required several treatment modalities.

Immune response to Encephalitozoon cuniculi infection

Microsporidia are obligate intracellular parasites, which can cause complications in immunocompromised individuals. Very little is known about the host immune response generated against these infectious agents. Encephalitozoon cuniculi is the best studied microsporidian and the protective immune response against this parasite is mediated by cytotoxic CD8(+) T cells.

Gamma delta T cell-deficient mice have a down-regulated CD8+ T cell immune response against Encephalitozoon cuniculi infection

Gamma(delta) T cells have been reported to play an essential effector role during the early immune response against a wide variety of infectious agents. Recent studies have suggested that the gamma(delta) T cell subtype may also be important for the induction of adaptive immune response against certain microbial pathogens. In the present study, an early increase of gamma(delta) T cells during murine infection with Encephalitozoon cuniculi, an intracellular parasite, was observed. The role of gamma(delta) T cells against E. cuniculi infection was further evaluated by using gene-knockout mice. Mice lacking gamma(delta) T cells were susceptible to E. cuniculi infection at high challenge doses. The reduced resistance of delta(-/-) mice was attributed to a down-regulated CD8+ immune response. Compared with parental wild-type animals, suboptimal Ag-specific CD8+ T cell immunity against E. cuniculi infection was noted in delta(-/-) mice. The splenocytes from infected knockout mice exhibited a lower frequency of Ag-specific CD8+ T cells. Moreover, adoptive transfer of immune TCR(alpha)beta+ CD8+ cells from the delta(-/-) mice failed to protect naive CD8(-/-) mice against a lethal E. cuniculi challenge. Our studies suggest that gamma(delta) T cells, due to their ability to produce cytokines, are important for the optimal priming of CD8+ T cell immunity against E. cuniculi infection. This is the first evidence of a parasitic infection in which down-regulation of CD8+ T cell immune response in the absence of gamma(delta) T cells has been demonstrated.

Alterations in the GnRH-LH system in relation to gonadal stage and Aroclor 1254 exposure in Atlantic croaker

Exposure of Atlantic croaker (Micropogonias undulatus) to the polychlorinated biphenyl mixture (Aroclor 1254, PCB; 1 mg/kg body wt/day for 30 days) during the early-recrudescence phase of the gonadal cycle results in the impairment of LH secretion and gonadal growth. In order to determine whether impairment was due to disruption of the stimulatory GnRH neuroendocrine pathway, we compared various parameters of the GnRH-LH system in early recrudescing vs. spermiating (mature) fish. Seabream GnRH (GnRH) content in the preoptic anterior hypothalamic area (POAH) and pituitary, pituitary GnRH receptor concentrations, and basal and GnRH analog (GnRHa)-induced LH secretion were significantly higher in gonadally mature croaker compared to early-recrudescing fish. In a subsequent experiment, the effects of PCB on the same neuroendocrine indices were investigated during the gonadal recrudescence phase of croaker. PCB exposure during the period of testicular maturation prevented the natural increase in GnRH content in the POAH but not in the pituitary. This finding suggests that PCB may impair GnRH synthesis in the POAH. The number of pituitary GnRH receptors also remained significantly lower in the PCB-exposed group, which was likely due to an impairment of GnRH release. The GnRH content in the POAH, number of pituitary GnRH receptors, and LH secretion in the PCB-exposed group were comparable to those in early-recrudescing fish, suggesting an impairment of normal maturation of the GnRH-LH system during the gonadal recrudescence phase. This impairment may be due to a direct action of PCB on GnRH neurons and/or indirectly via interference with other neurotransmitter pathways that modulate GnRH function.

Myocardial infarction with normal coronary arteries: the pathologic and clinical perspectives

Myocardial infarction with normal coronary arteries is a syndrome resulting from numerous conditions but the exact cause in a majority of the patients remains unknown. Cigarette smokers and cocaine users are more prone to develop this condition. The possible mechanisms causing myocardial infarction with normal coronary arteries are hypercoagulable states, coronary embolism, an imbalance between oxygen demand and supply, intense sympathetic stimulation, non-atherosclerotic coronary diseases, coronary trauma, coronary vasospasm, coronary thrombosis, and endothelial dysfunction. It primarily affects younger individuals, and the clinical presentation is similar to that of myocardial infarction with coronary atherosclerosis. Thrombolytics, aspirin, nitrates, and beta blockers should be instituted as a standard therapy for acute myocardial infarction. Once normal coronary arteries are identified on subsequent angiography, the calcium channel blockers could be added since coronary vasospasm appears to play a major role in the pathophysiology of this condition. The beta blockers should be avoided in cocaine-induced myocardial infarction because the coronary spasm may worsen. In myocardial infarction with normal coronary arteries, complications such as malignant arrhythmia, heart failure, and hypotension are generally less common, and prognosis is usually good. Recurrent infarction, postinfarction angina, heart failure, and sudden cardiac death are rare. Stress electrocardiography and imaging studies are not useful prognostic tests and long-term survival mainly depends on the residual left ventricular function, which is usually good.

Determination of heavy metals and pesticides in ginseng products

Medicinal plants may carry residuals of environmentally persistent pesticides or assimilate heavy metals in varying degrees. Several factors may influence contaminant accumulation, including species, level and duration of contaminant exposure, and topography. As part of a program for assessment of the quality of herbal medicines, we have analyzed 21 over-the-counter ginseng (Panax ginseng) products in various dosage forms. Chromium, mercury, and arsenic were undetectable above their limits of detection in both liquid and solid samples; while cadmium, lead, and nickel were present in the majority of samples. The chlorinated pesticide levels varied widely. In most samples, the total concentration of pesticides was below 100 ppb; while in 5 samples the total concentration exceeded 100 ppb.

Control of the cardiac muscarinic K+ channel by beta-arrestin 2

Control of the cardiac muscarinic K(+) current (i(K,ACh)) by beta-arrestin 2 has been studied. In Chinese hamster ovary cells transfected with m2 muscarinic receptor, muscarinic K(+) channel, receptor kinase (GRK2), and beta-arrestin 2, desensitization of i(K,ACh) during a 3-min application of 10 micrometer ACh was significantly increased as compared with that in cells transfected with receptor, channel, and GRK2 only (fade in current increased from 45 to 78%). The effect of beta-arrestin 2 was lost if cells were not co-transfected with GRK2. Resensitization (recovery from desensitization) of i(K,ACh) in cells transfected with beta-arrestin 2 was significantly slowed (time constant increased from 34 to 232 s). Activation and deactivation of i(K,ACh) on application and wash-off of ACh in cells transfected with beta-arrestin 2 were significantly slowed from 0.9 to 3.1 s (time to half peak i(K,ACh)) and from 6.2 to 13.8 s (time to half-deactivation), respectively. In cells transfected with a constitutively active beta-arrestin 2 mutant, desensitization occurred in the absence of agonist (peak current significantly decreased from 0.4 +/- 0.05 to 0.1 +/- 0.01 nA). We conclude that beta-arrestin 2 has the potential to play a major role in desensitization and other aspects of the functioning of the muscarinic K(+) channel.

Anxiolytic effects of kava extract and kavalactones in the chick social separation-stress paradigm

RATIONALE

Piper methysticum extract (kava kava) possesses numerous therapeutic properties, but it is unknown which of its principle constituents (kavalactones) subserve such effects.

OBJECTIVES

This experiment sought to characterize the putative anxiolytic properties of P. methysticum extract and its six principle kavalactones in the chick social separation-stress paradigm.

METHODS

Eight-day-old chicks received intraperitoneal injections of either vehicle, chlordiazepoxide (5.0 mg/ml per kg), P. methysticum extract (containing 30% kavalactones), kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin, or desmethoxyyangonin (30 mg/ml per kg for kava compounds) 30 min prior to being tested in the presence of two conspecifics or in isolation for a 3-min observation period. Latency to adopt a ventral recumbent posture to index sedation, number of vocalizations to index separation distress, and a composite pain score (in response to 50 microliters 0.10% formalin injection into the plantar surface of the foot) to index stress-induced analgesia served as dependent measures.

RESULTS

Both chlordiazepoxide and P. methysticum extract attenuated separation-induced distress vocalizations and stress-induced analgesia. Dihydrokavain attenuated separation-induced distress vocalizations.

CONCLUSIONS

These findings suggest that the anxiolytic effects of P. methysticum extract may be mediated, in part, by dihydrokavain.