A pair of 24-hydroperoxyl epimeric dammarane saponins from flower-buds of Panax ginseng

Further investigation on the saponins of the flower-buds of Panax ginseng C. A. Meyer has resulted in the isolation and structural elucidation of a pair of new 24-epimers of dammarane type saponins named ginsenoside I and II. The structures of the epimers were characterized on the basis of chemical and spectral evidence as 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]-20-S-O-beta-D-glucopyranosyl-3beta, 12beta,20(S)-trihydroxy-24xi-hydroperoxydammar-25-ene, except for their C-24 configurations. Ginsenoside I is a new triterpene glycoside, and ginsenoside II is a known compound first isolated from a natural plant.

Cyclic nucleotide phosphodiesterase type 5 activity limits blood flow to hypoperfused myocardium during exercise

BACKGROUND

Nitric oxide (NO) causes vasodilation by stimulation of guanylate cyclase in vascular smooth muscle to produce cGMP. The resultant vasodilator effect is regulated by a family of cGMP phosphodiesterases (PDEs). Sildenafil, a selective inhibitor of PDE5 used for treatment of erectile dysfunction, has been found to cause relaxation of isolated epicardial coronary artery segments. The present study examined the effects of sildenafil on coronary blood flow and hemodynamics during exercise in normal and ischemic heart.

METHODS AND RESULTS

In chronically instrumented normal dogs, sildenafil 2 mg/kg PO caused a slight but significant increase in left anterior descending (LAD) coronary blood flow during resting conditions, with a nonsignificant trend toward increased coronary flow during treadmill exercise. Exercise in the presence of LAD stenosis that decreased distal coronary pressure to 57+/-2 mm Hg reduced LAD flow during exercise from 69+/-8 to 41+/-7 mL/min (P:<0. 05), with hypoperfusion most severe in the subendocardium. At the same distal coronary pressure, sildenafil increased LAD flow in the ischemic region to 50+/-11 mL/min (P:<0.05). Increase in ischemic region blood flow produced by sildenafil was uniform across the LV wall, given that no change occurred in the transmural distribution of perfusion.

CONCLUSIONS

Inhibition of PDE5 with sildenafil caused vasodilation of coronary resistance vessels with an increase of blood flow into an ischemic myocardial region during exercise in the presence of coronary artery stenosis.

Loss of myocardial CK-MB into the circulation following 3.5 hours of swimming in a rat model

The purpose of this study was to document alterations of creatine kinase-B (CK-B) in the left and right ventricles of rats and CK-MB release into the circulation following a single bout of stressful prolonged intense exercise. Male Sprague-Dawley rats, with 8% bodyweight attached to each tail, were forced to swim 3.5 hours and were then sacrificed immediately (0 h PS), 3 hours (3 h PS), 24 hours (24 h PS), and 48 hours (48 h PS) post swimming, respectively. Sedentary (control) rats were sacrificed at rest. Serum CK-MB mass increased 2.1 times (8.9 microg/L; p < 0.01 vs. controls of 4.3 microg/L) and 1.4 times (6.0 microg/L; P < 0.01 vs. controls) at 0 h PS, and 3 h PS, respectively, and returned to baseline at 24 h PS. Western blot analysis indicated that CK-B of the right ventricle decreased 14% (p < 0.05), 20% (p < 0.01), and 12% (p < 0.05) at 3h PS, 24h PS and 48h PS, respectively. The CK-B of the left ventricles decreased 34% (p < 0.05) at 0 h PS, returned to baseline at 3 h PS, and was increased 39% (P < 0.01) at 48 h PS. Our findings demonstrate that a single bout of stressful, prolonged, intense exercise resulted in CK-B subunit loss from the myocardium, resulting in increased serum CK-MB concentrations, an indication of myocardial injury.

Comparison of anti-leukemic immunity against U937 cells in endurance athletes versus sedentary controls

To examine whether endurance athletes have higher anti-leukemic immunity than sedentary controls or not, we isolated peripheral blood mononuclear cells (MNC) from cyclists and sedentary controls to prepare conditioned media (CM) with various doses of phytohemagglutinin (PHA). The proliferation-inhibiting and differentiation-inducing activities of these PHA-MNC-CM on human leukemic U937 cells were investigated. Our results show that the growth inhibition activity of cyclists' PHA-MNC-CM were higher than that of controls. The dosage of PHA used to prepare MNC-CM to achieve about 90% growth inhibition was 5 microg/ml in the control group and was 2 microg/ml in the athletes group. The differentiation-inducing effects were evaluated by morphological scoring, superoxide production, and monocyte-associated antigen expression (CD14 and CD68). These three parameters all demonstrated the differentiation-inducing effect of MNC-CM increased with increasing dose of PHA. These effects were significantly greater in the athletic when compared to the sedentary control group at all doses of PHA. The levels of TNF-alpha and IFN-gamma PHA-MNC-CM increased in a PHA dose-dependent manner and were much higher in the athletic group when compared to the controls. We conclude that the capacity of endurance athletes to activate anti-leukemic immunity is significantly higher than that of sedentary controls.

Arrhythmogenic activity of cardiac muscle in pulmonary veins of the dog: implication for the genesis of atrial fibrillation

OBJECTIVE

Pulmonary veins are important foci of ectopic beats to initiate paroxysmal atrial fibrillation. The purpose of this study were to investigate the electrophysiological characteristics of excitable cells in canine pulmonary veins obtained from healthy and chronic rapid atrial pacing dogs and their responses to cardioactive agents.

METHODS

Transmembrane action potentials (APs) were recorded from multiple sites of pulmonary veins isolated from 17 healthy dogs and 14 dogs with chronic (6-8 weeks) rapid atrial pacing (780 bpm).

RESULTS

In normal superfusate, several types of electrical activities were identified, including silent electrical activity, fast response APs driven by electrical stimulation, and spontaneous fast or slow response APs (with or without early afterdepolarizations). The incidences of AP with an early afterdepolarization (93% versus 41%) was greater in chronic pacing dogs. The spontaneous activities were depressed by beta-adrenoceptor blocker, calcium channel blocker, adenosine and acetylcholine. High frequency (>8 Hz) irregular rhythms occurred spontaneously or were induced by cardioactive agents or electrical stimuli. The incidence of spontaneously occurring tachyarrhythmias was much higher in preparations from chronic pacing dogs (93%) than from control (12%). The tachyarrhythmias were suppressed by sodium channel blocker, potassium channel blocker or magnesium.

CONCLUSIONS

Pulmonary veins have arrhythmogenic ability through spontaneous activities or high-frequency irregular rhythms. The higher incidence of spontaneously occurring high-frequency irregular rhythms in chronic rapid atrial pacing dogs may account for the increased risk of atrial fibrillation in these dogs.

An analysis of meiotic pairing in trisomy 21 oocytes using fluorescent in situ hybridization

We report the use of chromosome 21-specific painting probes to analyze early stages of oogenesis in nine trisomy 21 fetuses. The proportion of cells in zygotene and pachytene in the trisomic ovaries ranged from 8 to 70% with a mean of 42% +/- 19 while the comparable values of euploid specimens ranged from 34 to 90% with a mean of 65% +/- 19. The low proportion of pairing cells may be the basis for the ovarian dysgenesis observed in some trisomy infants. Five percent of trisomic pachytene cells exhibited complete asynapsis which is an order of magnitude higher than that observed in euploid cells. A large fraction of the asynaptic cells were atretic which is consistent with the hypothesis of meiotic pairing as a signal for atresia. In addition, the asynaptic cells exhibited asynapsis of chromosomes other than 21, which we interpret as an interchromosomal effect of trisomy 21.

An increase in free radical production by means of an anion channel blocker DIDS in mouse peritoneal neutrophils

DIDS (4, 4'-diisothiocyanostilbene-2, 2'-disulfonic acid) has been recognized as an anion channel blocker. In this study, we demonstrated that DIDS significantly enhanced the production of free radicals in mouse peritoneal neutrophils. By means of a luminol-chemiluminescence (LCL) monitoring system, DIDS markedly increased LCL which could be suppressed by SOD, sodium azide (NaN3), EGTA and BAPTA-AM and only slightly inhibited by staurosporine (STP). Depletion of the endoplasmic reticulum (ER)-Ca2+ store by means of thapsigargin (TG) had no effects on DIDS-enhanced LCL, but DIDS significantly increased the amount of intracellular free calcium as monitored by means of fura-2 staining. These results indicate that DIDS may enhance free radical production mediated by Ca2+ release from the mitochondria. Both phorbol-12-myristate-13-acetate (PMA) and DIDS can induce increased translocation of p47-phox of the neutrophil to the membrane fraction, which is inhibited by STP pretreatment. Since free radical generation could reduce the cytoplasmic pH (pHi), we further examined whether DIDS was capable of inducing intracellular acidification. The result indicated that DIDS certainly lowered the pHi which was also suppressed by pretreatment with either NaN3 or NaCN, but not by diphenyleneiodonium (DPI). These findings lead us to propose a working hypothesis that DIDS mainly induces superoxide production accompanied by decreasing pHi mediated through a Ca2+ -dependent effect on the mitochondria rather than on NADPH oxidase. Using the lipophilic fluorescent dye DiOC6(3), we showed that DIDS decreased the transitional mitochondrial membrane potential. NaN3, but not STP or pyrrolidine dithiocarbamate (PDTC), antagonized DIDS in the course of decreasing the mitochondrial membrane potential. Taken together, all of these findings imply a possible role of anion channels of the mitochondria in modulating free radical production and intracellular acidification of neutrophils through alteration of the mitochondrial transition membrane potential and Ca2+ -release.

Comparison of landmark identification in traditional versus computer-aided digital cephalometry

The aim of this study was to assess landmark identification on digital images in comparison with those obtained from original radiographs. Ten cephalometric radiographs were selected randomly. Seven orthodontic residents identified 19 cephalometric landmarks on both the original radiographs and the digital images. To assess the concordance between landmarks identified on the original radiographs and on their digital counterparts, the x, y coordinates for each landmark in the 2 modalities were transformed with the identical references. The placement differences for 19 landmarks between 2 methods were calculated and their components in horizontal and vertical directions were analyzed respectively. Multivariate analysis of variance showed that the "cephalometric radiograph" and "landmark" variation had greater influence than that from "method" (landmark identification on digital / original radiograph). It was also noted that the differences of landmark identification between original radiographs and their digital counterparts were statistically significant. The landmarks with significant differences of horizontal component on the x-axis were Me, Gn, ANS, PNS, LIA. The differences were generally under 1 mm with the exception of Or, Me, PNS, LIA. The landmarks with significant differences of vertical component on the y-axis were Po, Or, Gn. The inter-observer error for each landmark in digital images was generally larger than that in the original radiographs. However, statistically significant differences of inter-observer errors between 2 modalities were only found for 4 of the 19 landmarks. These 4 landmarks, Po, Ar, ANS, and UM, should be scrutinized more carefully during potential applications of digital cephalometry.

A double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension

AIMS

Stevioside is a natural plant glycoside isolated from the plant Stevia rebaudiana which has been commercialized as a sweetener in Japan for more than 20 years. Previous animal studies have shown that stevioside has an antihypertensive effect. This study was to designed to evaluate the effect of stevioside in human hypertension.

METHODS

A multicentre, randomized, double-blind, placebo-controlled study was undertaken. This study group consisted of 106 Chinese hypertensive subjects with diastolic blood pressure between 95 and 110 mmHg and ages ranging from 28 to 75 years with 60 subjects (men 34, women 26; mean +/- s.d., 54.1+/-3.8 years) allocated to active treatment and 46 (men 19, women 27; mean +/- s.d., 53.7+/-4.1 years) to placebo treatment. Each subject was given capsules containing stevioside (250 mg) or placebo thrice daily and followed-up at monthly intervals for 1 year.

RESULTS

After 3 months, the systolic and diastolic blood pressure of the stevioside group decreased significantly (systolic: 166.0+/-9.4-152.6+/-6.8 mmHg; diastolic: 104.7 +/- 5.2-90.3+/-3.6 mmHg, P<0.05), and the effect persisted during the whole year. Blood biochemistry parameters including lipid and glucose showed no significant changes. No significant adverse effect was observed and quality of life assessment showed no deterioration.

CONCLUSIONS

This study shows that oral stevioside is a well tolerated and effective modality that may be considered as an alternative or supplementary therapy for patients with hypertension.

Minimal-access surgery in managing osteoporotic vertebral fractures with neurological deficits: a preliminary report

BACKGROUND

Spinal cord compression as a result of osteoporotic vertebral fracture is very rare. Surgical decompression of this recognized complication is indicated when the patient has persistent neurological deficits. Clinically, these patients are usually elderly and in a generally debilitated state. Using formal anterior spinal surgery might significantly violate the patient's respiratory mechanism and increase operative mobidity or mortality.

METHODS

From January 1996 to June 1998, the authors used a minimal-access spinal approach to perform 1-stage decompressive corpectomy, interbody fusion, and internal fixation with a Reduction-Fixation titanium spinal plate (Trifix, San Leandro, CA, USA) by thoracoscopic assistance in 8 patients with osteoporotic vertebral fractures from T11 to L1, and neurological deficits. This involved a modified 2-portal technique that required a 2-cm wound in order to initially introduce the thoracoscope, and a minithoracotomy wound (usually 5-6 cm) for surgical manipulation.

RESULTS

None of the operations resulted in injury to the great vessels, internal organs, or spinal cord. The average followup period was 30 months (range, 22-50 months). Complications included 1 radiolucent line around a vertebral screw, 1 lateral migration of a vertebral screw with bone graft displacement, 1 transient incisional wound hypesthesia, and 1 iliac donor site pain. In the current patients, the average neurological recovery was 1.1 grades on the Frankel scale.

CONCLUSION

The authors advocate that such a minimal-access technique with thoracoscopic assistance presented in the current study is an ideal alternative in treating patients with osteoporotic vertebral fractures and neurological deficits. It can obviate the necessity of dividing the diaphragm in order to facilitate exposure; no patient in the current series required intensive care postoperatively. However, the stability of the vertebral screw purchase in the osteoporotic spine is a matter of concern.

[An analysis of ionic flow of spontaneous slow action potential of guinea pig aortic vestibule]

Spontaneous slow action potentials of aortic vestibule of isolated guinea pig heart were intracellularlly recorded. Electrophysiological parameters examined are: maximal diastolic potential (MDP), amplitude of action potential (APA), maximal rate of depolarization of phase 0 (V(max)), velocity of diastolic depolarization of phase 4 (VDD), duration of 50% and 90% repolarization (APD(50) and APD(90)) and rate of pacemaker firing (RPF). It was found that (1) 0.5 micromol/L nisoldipine (Nis) significantly decreased APA, V(max), VDD and RPF (P<0.01); (2) 1.2 mmol/L tetrodotoxin (TTX) significantly decreased APA and V(max) (P<0.05), but VDD and RPF were significantly slowed down as compared with control (P<0.01); (3) 2 mmol/L 4-aminopyridine (4-AP) elicited a decrease in MDP, APA and V(max) (P<0.01), but an increase in VDD and RPF (P<0.01); (4) when 1.5 mmol/L CsCl was perfused for 5 min, the VDD and RPF were significantly decreased (P<0.05); and (5) under the condition of hypoxia and perfusion with deprived glucose content for 15 min, the VDD and RPF were decreased (P<0.01). The above results suggest that (1) in addition to Ca(2+), Na(+) current contributes to generation of 0 phase of depolarization of slow response activity in aortic vestibule mainly, and (2) in addition to the inward Ca(2+) and Na(+) current and attenuated K(+) current, I(f) current also plays some role in phase 4 of depolarization.

Chromosomal changes and clonality relationship between primary and recurrent hepatocellular carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is highly malignant and prone to recur after surgical treatment. Differentiation between a true relapse of HCC and a second primary tumor is of clinical importance. However, no convenient method is currently available.

METHODS

Comparative genomic hybridization (CGH) was used to analyze 31 pairs of initial and recurrent HCC samples obtained from patients undergoing 2 consecutive surgeries. The resulting chromosomal aberration profiles were used as genomic fingerprints to determine tumor clonalities and their relationships.

RESULTS

Eleven recurrent tumors with high clonal relationship (CR) values (>0.95) were found to be relapsed HCCs, and 11 tumors with CR values close to 0 were found to be second primary HCCs. The other 9 paired samples had inconclusive CR values between 0.95 and 0.4. Two were confirmed by hepatitis B virus integration and X chromosome inactivation analysis to be de novo cancers (CR values, 0.35 and 0. 23, respectively). Initial HCCs that subsequently relapsed accumulated more chromosomal aberration events than those that developed de novo HCC (mean, 16.1 +/- 4.5 vs. 5.4 +/- 4.8 events; P < 0.01). Also, they more frequently showed gains on chromosome arms 3q, 6p, 8q, and 17q and losses on 4q and 16p.

CONCLUSIONS

CGH is useful for chromosomal aberration study and tumor clonality analysis. More and characteristic genomic changes in the initial HCC suggest that subsequent tumor recurrence is a true relapse.

[Molecular phylogeny of canidae using mitochondrial cytochrome b DNA sequences]

372 bp mitochondrial cytochrome b DNA of blue fox, red fox, raccoon dog, and wolf were sequenced. Combined with the DNA fragments of dog, simien fox, and African wild dog, sequences were aligned and analyzed. There are 113 nucleotide sites substituted (30%). Molecular phylogenetic tree constructed by NJ method suggests that African wild dog is the earliest divergent. Wolf, dog, and simien fox which belong to genus Canis are combined into one branch which diverged earlier than raccoon dog, red fox and blue fox. Red fox is more related to blue fox than the other animals. The above result is in consistent with that of morphology.

Septic arthritis of the ankle joint

BACKGROUND

Septic arthritis of the ankle joint is a rare but serious disease. Very few reports in the literature have mentioned the method of care and treatment results of septic ankle. This study was designed to retrospectively review the treatment results and to analyze the prognostic factors of septic arthritis of the ankle inpatients at our hospital. We also formulated a protocol for the management of septic arthritis of the ankle joint.

METHODS

All records of those patients with a diagnosis of septic ankle from 1985 to 1997 were retrospectively reviewed. There were 29 patients that met the diagnostic criteria of septic arthritis of the ankle joint (21 male and 8 female patients; 6 children and 23 adults). The average follow-up time was 5.5 years (ranging from 1.5 to 13.7 years). The patients' ages, associated diseases, single or multiple joint(s) involved, timing of treatment, and the final results of these cases were assessed. The infecting organism and drug sensitivity were discussed to determine the proper antibiotics regimen.

RESULTS

Staphylococcus aureus was the most common infecting microorganism in the septic ankles. Combined therapy with oxacillin and gentamicine was effective against 88.1% of the infecting microorganisms. The poor prognostic factors for septic ankle included a positive bacterial culture, involvement of multiple joints simultaneously, a delay in treatment, and an increased number of associated diseases. In addition, a high proportion of patients with septic ankle had gouty arthritis (43.5%).

CONCLUSION

Early treatment (symptom duration of less than 5 days) significantly affected the final results. The early recognition and prompt treatment of this condition may reduce morbidity and mortality. Based on our results, oxacillin and gentamicine are recommended as the first-line antibiotics for the management of septic ankle.

Antioxidant activity of polyphenols from seeds of Vitis amurensis in vitro

AIM

To study the antioxidant action of five polyphenols (+) catechin, procyanidin B2, procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin isolated from the seeds of Vitis amurensis.

METHODS

The mouse liver homogenate lipid peroxidation assay was applied for the evaluation of the antioxidant activity in vitro.

RESULTS

(+) Catechin, procyanidin B2, procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin showed antioxidant activity with the IC50 values of 0.47, 0.25, 0.10, 0.02, and 0.03 mmol/L, respectively. The IC50 value of vitamin E used as a positive control was 0.13 mmol/L. The structural activity relationship was also analyzed. Procyanidins carrying a galloyl group possessed higher anti-lipid peroxidation activities. All dimers were found to be more potent than the non-galloylated momomer such as (+) catechin. However, the activity of the 4-->6 linked dimer seemed more preferable than 4-->8 linked dimer.

CONCLUSION

Procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin showed a more antioxidant activity than vitamin E did, and their activity is dependent on their substitution and polymerization patterns.

Atrial tachycardias originating from the atrial septum: electrophysiologic characteristics and radiofrequency ablation

INTRODUCTION

The characteristics of atrial tachycardia (AT) have varied widely among different reports. The anatomic locations of ATs may bias the results. We propose that septal ATs and free-wall ATs have different characteristics.

METHODS AND RESULTS

One hundred forty-one patients with AT underwent electropharmacologic study, endocardial mapping, and radiofrequency ablation. Forty-nine (34.7%) patients had septal AT originating from the anteroseptal, mid-septal, and posteroseptal areas. Tachycardia cycle length was similar between septal AT and free-wall AT (367 +/- 46 msec vs 366 +/- 58 msec, P > 0.05). More patients with septal AT required isoproterenol to facilitate induction (44.9% vs 31.5%, P <.0.05). Septal AT was more sensitive to adenosine than free-wall AT (84.4% vs 67.8%, P < 0.05). Only posteroseptal AT showed a positive P wave in lead V1 and negative P wave in all the inferior leads (II, III, aVF). Radiofrequency catheter ablation had a comparable success rate for septal AT and free-wall AT (96% vs 95%) without impairment of AV conduction. During follow-up of 49 +/- 13 months (range 17 to 85), the recurrence rate was similar for septal AT and free-wall AT (3.2% vs 4.6%, P = 0.08).

CONCLUSION

Septal AT has electrophysiologic characteristics that are distinct from those of free-wall AT. Catheter ablation of the septal AT is safe and effective.

Orificial tuberculosis and Kaposi's sarcoma in an HIV-negative individual

Orificial tuberculosis is a rare form of cutaneous tuberculosis. It happens mainly in immunocompromised patients and is characterized by rapidly ulcerating papules in the orifices, including oropharynx or anus, due to autoinoculation of internal tuberculosis. It is a symptom of advanced underlying disease. Kaposi's sarcoma occurs more frequently with the increase of HIV-infected patients. We report on an HIV-negative individual who developed rapid-deteriorating orificial tuberculosis concomitant with Kaposi's sarcoma and had a fatal outcome.

Subject-domain approach to the study of air pollution effects on schoolchildren's illness absence

In this paper, the authors propose a new statistical modeling technique, the subject-domain approach, which is theoretically proven to be equivalent to the time-domain approach in detecting an association between exposure and response with time trends. The authors use an empirical data set from a school absence monitoring study conducted during the 1994-1995 school year in Taiwan to demonstrate this subject-domain approach's application to environmental epidemiologic studies. Because the subject-domain models can control the influential personal confounding factors in the models, they show greater statistical power than the traditional time-domain approaches in determining the relation between air pollution and illness absences. The authors' models found that the schoolchildren's risks of illness absence were significantly related to acute exposures to nitrogen dioxide and nitrogen oxides with a 1-day lag (p < 0.01) at levels below the World Health Organization's guidelines. By contrast, the authors could not detect significant associations between air pollution and schoolchildren's absenteeism using time-domain approaches. Such findings imply that the models built on subject domain may be a general solution to the problem of the ecologic fallacy, which is commonly encountered in environmental and social epidemiologic studies.

Changes in superoxide dismutase activity and mRNA in vivo after short-term supplementation with trilinolein in rats

BACKGROUND

Oxidative damage plays a central role in atherogenesis and antioxidation defense mechanisms may prevent atherosclerosis. This study evaluated the effect of short-term supplementation of the natural lipophilic antioxidant trilinolein on superoxide dismutase (SOD) activity and SOD-mRNA gene expression in vivo in rat vital organs.

METHODS

Male Wistar rats (n = 8) were injected intraperitoneally with trilinolein (1 mM/ml/kg/day in 0.5% ethanol) daily for three consecutive days. Two control groups (n = 8) were administered saline or 0.5% ethanol in saline, respectively, for three days.

RESULTS

Assay of SOD activity and SOD-mRNA by Northern blotting in rat liver, spleen and brain showed significant increases in SOD activity and increased SOD-mRNA gene expression.

CONCLUSIONS

The natural lipophilic antioxidant trilinolein potentiates the SOD antioxidation defense mechanism and increases gene expression of SOD-mRNA after short-term supplementation in rats.

Dependence of electrogram duration in right posteroseptal atrium and atrium-pulmonary vein junction on pacing site: mechanism and implications regarding atrioventricular nodal reentrant tachycardia and paroxysmal atrial fibrillation

INTRODUCTION

The fractionated atrial electrogram, a signal helpful in identifying the target site for radiofrequency catheter ablation of the slow AV nodal pathway, is considered to arise from nonuniform anisotropic electrical activity. However, the effects of pacing sites and radiofrequency ablation on these electrograms are not clear. Similarly, the nature of the fractionated atrial electrogram in the atrium-pulmonary vein junction has yet to be determined.

METHODS AND RESULTS

Two experiments were performed in this study. Experiment 1 evaluated the fractionated atrial electrogram at target sites before and after slow AV nodal pathway ablation during sinus rhythm or during pacing from different sites. Group 1A consisted of 16 patients with dual AV nodal pathway physiology and AV nodal reentrant tachycardia who underwent successful ablation without residual slow AV nodal pathway. Group 1B consisted of 7 patients who underwent successful elimination of AV nodal reentry but with residual dual AV nodal pathway physiology. Group 1C consisted of 6 patients who still had AV nodal reentrant tachycardia after two applications of radiofrequency energy. In group 1D, there were 16 patients with dual AV nodal pathway physiology, but without inducible AV nodal reentrant tachycardia. In group 1E, there were 15 patients without dual AV nodal pathway physiology. Experiment 2 investigated the fractionated atrial electrogram in the ostium of the left and right superior pulmonary veins in 18 patients with paroxysmal atrial fibrillation (2A) and in 8 patients without paroxysmal atrial fibrillation (2B). Before radiofrequency ablation, electrogram duration in the right posteroseptal atrium during pacing from the middle coronary sinus or the right posterolateral atrium was shorter than that during pacing from the high right atrium (HRA) in all group 1 patients. After the successful elimination of the slow AV nodal pathway conduction in group 1A, atrial electrogram duration during HRA pacing was shorter than that before ablation. In experiment 2 patients, electrogram duration during pacing from the proximal or distal coronary sinus was shorter than that during pacing from HRA or sinus rhythm.

CONCLUSION

These findings suggest that the fractionated atrial electrograms in the right posteroseptal atrium and ostium of left or right superior pulmonary veins are potentially consistent with nonuniform anisotropic propagation. Alternations of electrogram characteristics after successful radiofrequency ablation of the slow AV nodal pathway may arise from the changes of nonuniform anisotropic activity in the right posteroseptal atrium.

[The expression of splicing fibronectin variants of cutaneous injuries in rats]

In situ hybridization with Digoxingenin labeled probes were used to build the relationship between incised cutaneous wounding intervals and the expression of splicing fibronectin variants (total, E III A and E III B Variants) in rats. The results showed that all forms of FN variants increased notably with the wounding time going on. E III A and E III B Variants were expressed abundantly 30 and 60 minutes after injury, while few in normal skin.

[The foundation of the injury model on cultured human fetal lung fibroblasts and its immunohistochemistry research]

Cultured human fetal lung Fbs was first used to study the relationship between wound age and the change of cFn synthesized by Fbs in Vitro. A sterilized injector was applied to scrap the cultured confluent Fbs and a "wound" was obtained. Fbs around the wound was seen to change from a stationary stage to an active stage. Using the method of immunochemistry and image analysis system (IAS), cFn synthesized by Fbs around the wound was observed at once, 30 min, 1 h, 3 h and 6 h after injury. It was found that cFn began to change 1 h after injury and increased continually within 6 h. It suggests that the change of cFn synthesized by Fbs is time-dependent after injury and this approach breaks a new path in the study on estimation of wound age.

Genomic characterization of the human heterotrimeric G protein alpha, beta, and gamma subunit genes

Heterotrimeric guanine nucleotide binding proteins (G proteins) transduce extracellular signals received by transmembrane receptors to effector proteins. Each subunit of the G protein complex is encoded by a member of one of three corresponding gene families. Currently, 16 different members of the alpha subunit family, 5 different members of the beta subunit family, and 11 different members of the gamma subunit family have been described in mammals. Here we have identified and characterized Bacterial Artificial Chromosomes (BACs) containing the human homologs of each of the alpha, beta, and gamma subunit genes as well as a G alpha11 pseudogene and a previously undiscovered G gamma5-like gene. The gene structure and chromosome location of each gene was determined, as were the orientations of paired genes. These results provide greater insight into the evolution and functional diversity of the mammalian G protein subunit genes.

Ventricular tachycardia in a patient with primary hyperparathyroidism

We present a case of primary hyperparathyroidism with hypercalcemia in a patient who had spontaneous attacks of ventricular tachycardia. Right ventricular burst pacing reproducibly induced ventricular tachycardia in the electrophysiological laboratory after intravenous administration of calcium-gluconate, and verapamil could terminate the tachycardia. After resection of the parathyroid adenoma, the calcium level was restored to normal, and ventricular tachycardia did not occur again during the follow-up period.