Unusual complication of retrograde dissection to the coronary sinus of valsalva during percutaneous revascularization: a single-center experience and literature review

BACKGROUND

While coronary dissection, which is one of the most frequently occurring complications during interventional procedures, has various forms, extensive coronary dissection retrograde to the coronary sinus of Valsalva (CSV) is very rarely observed.

METHODS AND RESULTS

Within the last 5 years, we retrospectively reviewed our experience with 4,700 consecutive patients who underwent angioplasty procedures, 7 of whom (0.15%) developed extensive coronary dissection retrograde to the CSV. Six of the seven patients developed retrograde dissection of the right CSV during angioplasty to the right coronary artery. One of the seven patents developed retrograde dissection of the left CSV during angioplasty to the left anterior descending artery. Retrograde dissection, which extended to the ascending aorta in two patients, was observed by transthoracic echocardiography and surgical findings, respectively. Five patients were successfully treated by coronary stenting. However, this complication caused four patients to have acute myocardial infarctions, resulting in emergency surgery for one patient and in-hospital death for another.

CONCLUSIONS

Our experience increased our understanding of this very rare complication. However, this complication may be life threatening, and patients in this clinical setting may have a potential risk for acute myocardial infarction, emergency surgery, or even sudden cardiac death. Therefore, it is important to learn how to promptly diagnose and manage this complication.

Molecular therapy with recombinant antisense c-myc adenovirus for human gastric carcinoma cells in vitro and in vivo

BACKGROUND AND AIMS

This study used a recombinant antisense c-myc adenovirus (Ad-ASc-myc) to evaluate how alterations of c-myc expression in the SGC7901 human gastric carcinoma cells could influence the proliferation, apoptosis and the growth of human gastric tumors in nude mice.

METHODS

The human gastric carcinoma cell line, SGC7901, treated with Ad-ASc-myc or adenovirus recombinants carrying LacZ gene (Ad-LacZ) were analyzed by using X-gal stain, MTT, DNA ladder, TUNEL assay, flow cytometric analysis, polymerase chain reaction and western blot in vitro. The tumorigenicity and experimental therapy in nude mice models were assessed in vivo.

RESULTS

The Ad-ASc-myc could strongly inhibit cell growth and induce apoptosis in SGC7901 cells. The proliferation of the Ad-ASc-myc-infected SGC7901 cells was reduced by 44.1%. The mechanism of killing gastric carcinoma cells by Ad-ASc-myc was found to be apoptosis, which was detected by the use of a DNA ladder, TUNEL and flow cytometric analysis. Infection of Ad-ASc-myc in nude mice showed that all three mice failed to form tumors from the 7 to 30 day period, compared with injection of Ad-LacZ and parent SGC7901 cells. Experimental therapy on the nude mice bearing subcutaneous tumors of SGC7901 cells showed that intratumor instillation of Ad-ASc-myc inhibited the growth of the tumors. Recombinant antisense c-myc adenovirus-treated tumors were inhibited by 68.9%, compared with tumors injected with Ad-LacZ and control (LacZ and phosphate-buffered saline).

CONCLUSION

The expression of Ad-ASc-myc can inhibit growth and induce apoptosis of gastric cancer cells in vitro and in vivo and thus is a potential clinical utility in gene therapy for the treatment of gastric carcinoma.

[Preliminary study on orthodontic treatment before and after distraction osteogenesis]

OBJECTIVE

To get some guidelines for the orthodontic treatment before and after distraction osteogenesis (DO).

METHODS

DO was performed in 4 patients maxilla and two for mandible. The patients were aged from 19 to 25 (average 21.5). We try to sum up the procedures and clinical experiences of pre- and post-surgery orthodontics.

RESULTS

The procedures and experiences obtained are the followings: 1. Pre-surgery orthodontics for DO is simplified as alignment of dental arch in a short period. 2. Post-surgery orthodontics for DO is more complicated and peculiar. The main task is to make the opened posterior teeth occlude as soon as possible by light force vertical elastics. At the same time, some cross elastics may be needed for correction of posterior occlusal relationship. 3. Expansion of upper arch may be needed in some patients because of constricted dental arch. 4. Class II or III elastics may be used for prevention of relapse after DO.

CONCLUSIONS

DO is a new technique in orthognathic surgery. Post-surgery orthodontics is more complicated and important in the treatment course.

[The change of genioglossus muscle activity of OSAS patients with and without snoreguard]

OBJECTIVE

The effect of snoreguard on the genioglossus (GG) muscle activity of OSAS patients was investigated.

METHODS

Fifteen male patients with mild to severe OSAS were diagnosed by overnight polysomnographic and GG EMG studies, and reexamined with snoreguard. GG muscle activities of these patients with and without snoreguard were compared.

RESULTS

The results revealed that the overnight GG muscle activity decreased significantly and the fluctuating GG muscle activity was improved effectively by the treatment of snoreguard.

CONCLUSION

The treatment mechanisms of mandibular advancing appliance on OSAS are mechanical enlargement of upper airway and the passivity of GG muscle during treatment.

Efficacy and safety of acetaminophen in the treatment of migraine: results of a randomized, double-blind, placebo-controlled, population-based study

BACKGROUND

Although most persons with migraine treat their headaches with over-the-counter medication, systematic data on the safety and efficacy of widely used treatment, including acetaminophen, are sparse.

METHODS

This is a randomized, double-blind, placebo-controlled study comparing oral acetaminophen, 1000 mg (two 500-mg Extra Strength Tylenol tablets), with identical placebo in the treatment of a single acute migraine attack. Eligible subjects met International Headache Society diagnostic criteria for migraine with or without aura. Patients who usually required bed rest with their headaches or who vomited more than 20% of the time were excluded.

MAIN OUTCOME MEASURES

The percentage of subjects who, at 2 hours after dosing, experienced a change in baseline pain intensity from severe or moderate pain to mild or no pain (headache response); and pain intensity difference from baseline at the 2-hour postmedication assessment.

RESULTS

The headache response rate 2 hours after dosing was 57.8% in the acetaminophen group and 38.7% in the placebo group (P =.002). Pain-free rates at 2 hours were 22.4% in the acetaminophen group and 11.3% in the placebo group (P =.01). The mean pain intensity difference from baseline 2 hours after dosing was 1.08 in the acetaminophen group and 0.73 in the placebo group (P<.001). At 2 hours, other migraine headache characteristics, such as functional disability (P =.002), photophobia (P =.02), and phonophobia (P =.08), were significantly improved after treatment with acetaminophen vs placebo.

CONCLUSIONS

Acetaminophen was highly effective for treating pain, functional disability, photophobia, and phonophobia in a population-based sample of persons with migraine, excluding the most disabled persons with migraine. The drug also had an excellent safety profile and was well tolerated. Arch Intern Med. 2000;160:3486-3492.

Aminoanthraquinones as novel ligands at the polyamine binding site on the N-methyl-D-aspartate receptor complex

As part of a drug discovery program using high-throughput radioligand-binding assays, aminoanthraquinones were identified as potential modulators of N-methyl-D-aspartate (NMDA) receptor function. Aminoanthraquinones may represent a novel class of polyamine binding site ligands with a unique pharmacophore and may facilitate the rational design of novel NMDA-receptor modulators.

Dobutamine enhances both contractile function and energy reserves in hypoperfused canine right ventricle

Although the beta(1)-adrenergic agent dobutamine is used clinically to provide inotropic support to the failing myocardium, it could jeopardize the myocardium by depleting energy reserves. This investigation delineated the contractile and energetic effects of low versus high dobutamine doses in the hypoperfused right ventricular (RV) myocardium. The right coronary artery (RCA) of anesthetized dogs was cannulated for controlled perfusion with arterial blood, and regional RV contractile function was measured. RCA perfusion pressure was lowered from 100 mmHg baseline to 40 mmHg, and flow fell by 54%. At 15-min hypoperfusion, dobutamine was infused into the RCA at either 0.01 (low-dose dobutamine) or 0.06 microgram. kg(-1). min(-1) (high-dose dobutamine) for 15 min. Regional power (systolic segment shortening x isometric developed force x heart rate) stabilized at 63% of baseline during hypoperfusion. Low-dose dobutamine restored power to baseline but did not increase RV myocardial O(2) consumption (MVO(2)) and thus increased myocardial O(2) utilization efficiency (O(2)UE:power/MVO(2)). At 5 min, high-dose dobutamine enhancement of power was similar to that of low-dose dobutamine, but by 15 min, power and O(2)UE fell to untreated levels. Remarkably, low-dose dobutamine tripled cytosolic phosphorylation potential; in contrast, high-dose dobutamine lowered phosphorylation potential to 45% of the untreated value. Analyses of glucose uptake and glycolytic intermediates revealed sustained enhancement of glycolysis by low-dose dobutamine, but glycolysis became limited at glyceraldehyde 3-phosphate dehydrogenase during high-dose dobutamine treatment. In summary, low-dose dobutamine improved mechanical performance and efficiency of the hypoperfused RV myocardium while increasing myocardial energy reserves, but high-dose dobutamine failed to sustain improved function and depleted energy reserves. Dobutamine is capable of improving both contractile function and cellular energetics in the hypoperfused RV myocardium, but dosage should be carefully selected.

Growth hormone improves bioenergetics and decreases catecholamines in postinfarct rat hearts

The aims of this study were to examine, in vivo, the effects of GH treatment on myocardial energy metabolism, function, morphology, and neurohormonal status in rats during the early postinfarct remodeling phase. Myocardial infarction (MI) was induced in male Sprague Dawley rats. Three different groups were studied: MI rats treated with saline (n = 7), MI rats treated with GH (MI + GH; n = 11; 3 mg/kg x day), and sham-operated rats (sham; n = 8). All rats were investigated with 31P magnetic resonance spectroscopy and echocardiography at 3 days after MI and 3 weeks later. After 3 weeks treatment with GH, the phosphocreatine/ATP ratio increased significantly, compared with the control group (MI = 1.69 +/- 0.09 vs. MI + GH = 2.42 +/- 0.05, P < 0.001; sham = 2.34 +/- 0.08). Treatment with GH significantly attenuated an increase in left ventricular end systolic volume and end diastolic volume. A decrease in ejection fraction was prevented in GH-treated rats (P < 0.05 vs. MI). Myocardial and plasma noradrenaline levels were significantly lower in MI rats treated with GH. These effects were accompanied by normalization of plasma brain natriuretic peptide levels (sham = 124.1 +/- 8.4; MI = 203.9 +/- 34.7; MI + GH = 118.3 +/- 8.4 ng/ml; P < 0.05 vs. MI). In conclusion, GH improves myocardial energy reserve, preserves left ventricular function, and attenuates pathologic postinfarct remodeling in the absence of induction of left ventricular hypertrophy in postinfarct rats. The marked decrease in myocardial content of noradrenaline, after GH treatment, may protect myocardium from adverse effects of catecholamines during postinfarct remodeling.

Induction of cardiomyopathy in severe combined immunodeficiency mice by transfer of lymphocytes from patients with idiopathic dilated cardiomyopathy

Growing evidence suggests that autoimmune mechanisms play an important role in the pathogenesis of idiopathic dilated cardiomyopathy (DCM). The aim of the study was to evaluate the effects of transfer of lymphocytes from patients with DCM into severe combined immunodeficiency (SCID) mice on the heart structure and function. Thirty CB-17 SCID (6-8 weeks old) mice were used and divided into 3 groups (n = 10). Mice were injected intraperitoneally with up to 25 x 10(6) peripheral blood lymphocytes (PBL) from either patients with DCM which contain human autoantibodies against cardiac beta1-adrenergic receptors and M2-muscarinic receptors (DCM group) or PBL from healthy controls (control-H group). Ten mice did not receive any injections and were used as baseline controls (control-N group). Echocardiography and morphological studies were performed seventy five days after the transfer. Results showed that in DCM group, left ventricle dimensions (LVD) in diastole were increased (4.2 +/- 0.1mm) as compared to both control-H group (3.8 +/- 0.1mm) and control-N group (3.6 +/- 0.1 mm) (p < 0.01). Further, there was a trend for increased LVD in systole. Fractional shortening was not different between groups. Histological evaluation revealed accumulation of human lymphocytes in the capillaries and scarce infiltration of the lymphocytes in the hearts from DCM group. Diffuse fibrosis was significant increased in DCM mice as compared to mice receiving PBL from normal subjects (2.2 +/- 0.3% vs. 0.8 +/- 0.1%, p < 0.01). In conclusion, transfer of the PBL from the patients with DCM was able to induce early stage of heart dilatation in SCID mice. These data provide for the first time the direct evidence supporting that the autoimmune mechanism is important in the pathogenesis of human DCM.

The practice of evidence-based medicine in an acute medical ward: retrospective study

OBJECTIVE

To review the practice of evidence-based medicine with respect to drug treatment given to medical in-patients.

DESIGN

Retrospective study.

SETTING

Teaching hospital, Hong Kong.

PATIENTS

Medical records of 129 consecutive patients who were admitted to the acute adult general medical ward from 1 September 1998 to 30 September 1998 were reviewed.

MAIN OUTCOME MEASURES

Primary diagnoses, drug treatments prescribed, and the level of evidence (based on a literature search of randomised controlled trials and relevant studies) that supported the treatment given.

RESULTS

For the 129 patients studied, 91 drug interventions had been prescribed on 312 occasions. Treatment that was supported by randomised controlled trials was prescribed in 162 (52.9%) cases. In 121 (38.8%) cases, patients were given standard and commonly used drugs that were not supported by evidence from clinical trials, and in 29 (9.3%) cases, the treatments given had no substantial supporting evidence. The management of some frequently encountered medical conditions was not based on trial data, because the relevant studies had not been conducted.

CONCLUSION

Basing treatment on comparative efficacy results is a worthwhile goal, but there are limitations in conducting literature searches to identify relevant trials and studies. Evidence-based medical practice is not applicable in a large number of commonly encountered conditions.

Ral GTPases contribute to regulation of cyclin D1 through activation of NF-kappaB

Ral GTPases have been implicated as mediators of Ras-induced signal transduction from observations that Ral-specific guanine nucleotide exchange factors associate with Ras and are activated by Ras. The cellular role of Ral family proteins is unclear, as is the contribution that Ral may make to Ras-dependent signaling. Here we show that expression of activated Ral in quiescent rodent fibroblasts is sufficient to induce activation of NF-kappaB-dependent gene expression and cyclin D1 transcription, two key convergence points for mitogenic and survival signaling. The regulation of cyclin D1 transcription by Ral is dependent on NF-kappaB activation and is mediated through an NF-kappaB binding site in the cyclin D1 promoter. Ral activation of these responses is likely through an as yet uncharacterized effector pathway, as we find activation of NF-kappaB and the cyclin D1 promoter by Ral is independent of association of Ral with active phospholipase D1 or Ral-binding protein 1, two proteins proposed to mediate Ral function in cells.

Three-dimensional echocardiographic image of atrial septal aneurysm: report of two cases

Atrial septal aneurysm (ASA) is a rare congenital anomaly. It may occur as an isolated pathology or in association with other cardiovascular lesions such as mitral valve disease, atrial septal defect, and others. The diagnosis of ASA became more widely recognized with the use of 2-dimensional echocardiography. Three-dimensional echocardiography is a recently developed imaging technique. It can be used as an adjunct to conventional transesophageal echocardiography. Images of different aspects of cardiac chambers and valves can be obtained with 3-dimensional echocardiography. This paper reports on 2 cases of different types of ASA imaged by 3-dimensional echocardiography. The images were obtained from the left and right atriums, respectively. The 3-dimensional image taken from the left atrium showed the ASA to be a localized concave structure, and the 3-dimensional image taken from the right atrium showed the ASA to be a localized bulging structure. Our pictures are the first reported 3-dimensional echocardiographic images of ASA. We hope this report will allow for a more comprehensive understanding of its pathology.

The integrin-linked kinase regulates the cyclin D1 gene through glycogen synthase kinase 3beta and cAMP-responsive element-binding protein-dependent pathways

The cyclin D1 gene encodes the regulatory subunit of a holoenzyme that phosphorylates and inactivates the pRB tumor suppressor protein. Cyclin D1 is overexpressed in 20-30% of human breast tumors and is induced both by oncogenes including those for Ras, Neu, and Src, and by the beta-catenin/lymphoid enhancer factor (LEF)/T cell factor (TCF) pathway. The ankyrin repeat containing serine-threonine protein kinase, integrin-linked kinase (ILK), binds to the cytoplasmic domain of beta(1) and beta(3) integrin subunits and promotes anchorage-independent growth. We show here that ILK overexpression elevates cyclin D1 protein levels and directly induces the cyclin D1 gene in mammary epithelial cells. ILK activation of the cyclin D1 promoter was abolished by point mutation of a cAMP-responsive element-binding protein (CREB)/ATF-2 binding site at nucleotide -54 in the cyclin D1 promoter, and by overexpression of either glycogen synthase kinase-3beta (GSK-3beta) or dominant negative mutants of CREB or ATF-2. Inhibition of the PI 3-kinase and AKT/protein kinase B, but not of the p38, ERK, or JNK signaling pathways, reduced ILK induction of cyclin D1 expression. ILK induced CREB transactivation and CREB binding to the cyclin D1 promoter CRE. Wnt-1 overexpression in mammary epithelial cells induced cyclin D1 mRNA and targeted overexpression of Wnt-1 in the mammary gland of transgenic mice increased both ILK activity and cyclin D1 levels. We conclude that the cyclin D1 gene is regulated by the Wnt-1 and ILK signaling pathways and that ILK induction of cyclin D1 involves the CREB signaling pathway in mammary epithelial cells.

Computer modeling of interactions of an electric motor, circulatory system, and rotary blood pump

The innovative ventricular assist systems (IVAS) is the next generation ventricular assist device for use as a permanent implantable device. Its practical application depends upon control of the electric motor and interactions of the electric motor, blood pump, and circulatory system. Computer modeling and simulation are necessary to investigate and evaluate the interactions and feasibility of sophisticated control algorithms. In this paper, a computer model of the complete system, including the cardiovascular system, blood pump, and electric motor, is proposed. The model is obtained based on an electric circuit model of the cardiovascular system, a parametric model of the blood pump, and a dynamic model of the electric motor. The cardiovascular system uses nonlinear parameters to simulate the time-varying property of the ventricles, and the cannula collapse effect caused by over-pumping. The blood pump model can be obtained either from pump design data, or test data. The motor control can be operated with closed-loop regulation, depending upon physiologic requirements. Different operation modes (current or speed) of the electric motor can be simulated. The computer model is implemented using MATLAB. Various motor operation modes are simulated and their effects are evaluated. By adjusting the motor input, the pump can achieve proper output so that normal physiology can be obtained. In addition to evaluating existing operation modes and their effect on the physiologic system, the computer simulation results show that this computer model can contribute significantly to the development of new physiologic control algorithms. It is demonstrated that, using this motor-pump-physiology interaction model, development of an innovative ventricular assist system can be greatly facilitated.

Effects of a mandibular repositioner on obstructive sleep apnea

The purpose of this study was to investigate the effects of a mandibular repositioner on airway, sleep, and respiratory variables in patients with obstructive sleep apnea. Twenty-two patients selected for this study were confirmed with a diagnosis of obstructive sleep apnea based on initial nocturnal polysomnography. The patients were fitted with a mandibular repositioner designed to hold the mandible anteroinferiorly. Six months later, an outcome polysomnographic study was undertaken for each patient with the appliance in place. Lateral cephalometric radiographs in the upright position were also obtained before and after 6 months of treatment. The respiratory disturbance index decreased in 21 of the 22 patients with the appliance in place. The mean respiratory disturbance index of the 22 patients decreased significantly from 40.3 to 11.7 events per hour (P <.01). Some 59.1% of subjects were considered a treatment success with follow-up respiratory disturbance index < 10 events per hour. The mean minimum blood oxygen saturation level during sleep also improved significantly from 73.4% to 81.3% (P <. 01). The mandibular repositioner was constructed to position the mandible at 75% of the maximal mandibular advancement and with a 7 mm opening between the upper and lower incisors, and no aberrant effect on temporomandibular joint was noted. The retropalatal airway space increased and the cross-sectional area of the soft palate and the vertical distance of the hyoid bone to the mandibular plane decreased significantly. The tongue posture became significantly flatter. A significant linear correlation was found between the reduction in apnea index and specific craniofacial skeletal structures (length of anterior cranial base, mandibular plane angle, and upper to lower facial height ratios, P <.05). Subjects with a smaller reduction in apnea index tended to have shorter anterior cranial bases, steeper mandibular planes, and smaller upper to lower facial height ratios. We conclude that a mandibular repositioner may be an effective treatment alternative for obstructive sleep apnea and that a reduction in the frequency of apneic episodes is mainly attributed to the effects of the appliance on oropharyngeal structures.

Evolution in the treatment of choledochus cyst

PURPOSE

The aim of this study was to reevaluate the results of the short jejunal interposition (Chicago-Beijing procedure) in the treatment of choledochus cyst and search for the way of further improvement.

METHODS

A retrograde study of some 500 surgical cases was made. The immediate postoperative and 10-year follow-up results of the 3 main procedures used in 3 different time periods were compared. Twenty-five redo cases of the above-mentioned series and another 6 referred from other hospitals were analyzed specially for the main cause of complications.

RESULTS

Ten-year uneventful follow-up occurred in more than 90% of cases after the Chicago-Beijing procedure, which was evidently superior to other 2 kinds of methods. Having solved the problems of the abnormal pancreatico-biliary communication and entero-biliary reflux, it remains the challenge of the anastomosis stricture. Malignancy degeneration disappeared dramatically after total excision of the cyst.

CONCLUSIONS

Chicago-Beijing procedure proved to be the most reliable operation for choledochus cyst in comparison with the other 2 conventional methods in BCH. The prevention of anastomosis stricture should be emphasized for the further improvement of the surgical result.

Transforming growth factor-beta1 recruits histone deacetylase 1 to a p130 repressor complex in transgenic mice in vivo

Transforming growth factor (TGF)-beta1 functions as a tumor suppressor in vivo. Using transgenic mice, we show that hepatic TGF-beta1 overexpression inhibits abundance of the cyclin-dependent kinase activating tyrosine phosphatase cdc25A protein. The reduction in cdc25A protein levels was associated with increased binding of histone deacetylase 1 to p130 in the hepatic extracts. In cultured cells, HDAC1/p130 overexpression inhibited activity of the cdc25A promoter through an E2F site. TGF-beta1 treatment enhanced p130 binding to the cdc25A promoter E2F site assessed in chromatin immunoprecipitation assays. Hepatic proliferation induced by partial hepatectomy was associated with a decrease in the amount of HDAC1 bound to p130, without a significant decrease in p130 abundance, suggesting that HDAC1 binding to p130 may be regulated by proliferative stimuli. The induction of cdc25A abundance induced by partial hepatectomy correlated with the induction of DNA synthesis. These studies suggest that TGF-beta1 may enhance HDAC1 binding to p130 in vivo, thereby inhibiting cdc25A gene expression. TGF-beta1 regulation of HDAC1/pocket protein associations may provide a link between chromatin remodeling proteins and cdk inhibition through induction of cdc25A in vivo.

Transgenic overexpression of caveolin-3 in skeletal muscle fibers induces a Duchenne-like muscular dystrophy phenotype

It recently was reported that Duchenne muscular dystrophy (DMD) patients and mdx mice have elevated levels of caveolin-3 expression in their skeletal muscle. However, it remains unknown whether increased caveolin-3 levels in DMD patients contribute to the pathogenesis of DMD. Here, using a genetic approach, we test this hypothesis directly by overexpressing wild-type caveolin-3 as a transgene in mice. Analysis of skeletal muscle tissue from caveolin-3- overexpressing transgenic mice reveals: (i) a dramatic increase in the number of sarcolemmal muscle cell caveolae; (ii) a preponderance of hypertrophic, necrotic, and immature/regenerating skeletal muscle fibers with characteristic central nuclei; and (iii) down-regulation of dystrophin and beta-dystroglycan protein expression. In addition, these mice show elevated serum creatine kinase levels, consistent with the myo-necrosis observed morphologically. The Duchenne-like phenotype of caveolin-3 transgenic mice will provide an important mouse model for understanding the pathogenesis of DMD in humans.

Involvement of calcineurin in angiotensin II-induced cardiomyocyte hypertrophy and cardiac fibroblast hyperplasia of rats

A rapidly emerging body of literature implicates a pivotal role for the Ca2+-calmodulin-dependent phosphatase, calcineurin, as a cellular target for a variety of Ca2+-dependent signaling pathways culminating in cardiac hypertrophy. The aim of the present study was to test whether calcineurin is involved in the signal transduction of angiotensin II (AngII)-induced cardiac myocyte hypertrophy and fibroblast hyperplasia. Firstly, we observed that calcineurin activity was significantly increased in AngII-stimulated cardiac myocytes as well as fibroblasts, but was markedly inhibited by Losartan (50 micromol/l), H7 (50 micromol/l), and Fura-2/AM (5 micromol/l). It is indicated that AngII-induced activation of calcineurin is through an ATI receptor, may be dependent on the sustained increases of [Ca2+]i, and be regulated by protein kinase C. In a second experiment, we found that cyclosporin (0.1-10micromol/l), a specific inhibitor of calcineurin, decreased the protein synthesis rate in AngII-stimulated cardiomyocytes and the DNA synthesis rate in AngII-treated fibroblasts in a dose-dependent manner. In the latter experiment, calcineurin inhibition reduced the mRNA level of the atrial natriuretic factor gene. These results indicate that calcineurin is involved in the signal transduction of AngII-induced cardiomyocyte hypertrophy and fibroblast hyperplasia.

Gut-enriched Krüppel-like factor represses cyclin D1 promoter activity through Sp1 motif

Cancer cells differ from normal cells in many characteristics including loss of differentiation and uninhibited cell proliferation. Recent studies have focused on the identification of factors contributing to cell growth and differentiation. Gut-enriched Krüppel-like factor (GKLF or KLF4) is a newly identified eukaryotic transcription factor and has been shown to play a role in regulating growth arrest. We have previously shown that GKLF mRNA levels were significantly decreased in colon cancer tissues, and that over-expression of GKLF in colonic adenocarcinoma cells (HT-29) resulted in reduction of cyclin D1 (CD1) mRNA and protein levels. The current study was undertaken to determine the mechanisms by which GKLF inhibited CD1 expression. In a transient transfection system, GKLF suppressed CD1 promoter activity by 55%. Sequential deletion and site-directed mutation analysis of the CD1 promoter have identified the sequence between -141 and -66, a region containing an Sp1 response element, to be essential for GKLF function. By electrophoretic mobility gel shift assay, recombinant GKLF and nuclear extracts from HT-29 cells were found to bind to the Sp1 motif on the CD1 promoter. The inhibitory effect of GKLF on the CD1 promoter activity was completely abolished by excessive amount of Sp1 DNA and GKLF significantly reduced the stimulatory function of Sp1 suggesting that GKLF and Sp1 may compete for the same binding site on the CD1 promoter. These results indicate that GKLF is a transcriptional repressor of the CD1 gene and that the inhibitory effect of GKLF is, in part, mediated by interaction with the Sp1 binding domain on its promoter.

The cyclin D1 gene is transcriptionally repressed by caveolin-1

The cyclin D1 gene encodes the regulatory subunit of the holoenzyme that phosphorylates and inactivates the retinoblastoma pRB protein. Cyclin D1 protein levels are elevated by mitogenic and oncogenic signaling pathways, and antisense mRNA to cyclin D1 inhibits transformation by the ras, neu, and src oncogenes, thus linking cyclin D1 regulation to cellular transformation. Caveolins are the principal protein components of caveolae, vesicular plasma membrane invaginations that also function in signal transduction. We show here that caveolin-1 expression levels inversely correlate with cyclin D1 abundance levels in transformed cells. Expression of antisense caveolin-1 increased cyclin D1 levels, whereas caveolin-1 overexpression inhibited expression of the cyclin D1 gene. Cyclin D1 promoter activity was selectively repressed by caveolin-1, but not by caveolin-3, and this repression required the caveolin-1 N terminus. Maximal inhibition of the cyclin D1 gene promoter by caveolin-1 was dependent on the cyclin D1 promoter T-cell factor/lymphoid enhancer factor-1-binding site between -81 to -73. The T-cell factor/lymphoid enhancer factor sequence was sufficient for repression by caveolin-1. We suggest that transcriptional repression of the cyclin D1 gene may contribute to the inhibition of transformation by caveolin-1.

p300 and p300/cAMP-response element-binding protein-associated factor acetylate the androgen receptor at sites governing hormone-dependent transactivation

The androgen receptor (AR) is a sequence-specific DNA-binding protein that plays a key role in prostate cancer cellular proliferation by dihydrotestosterone and the induction of secondary sexual characteristics. In this study we demonstrate that the AR can be modified by acetylation in vitro and in vivo. p300 and p300/cAMP-response element-binding protein acetylated the AR at a highly conserved lysine-rich motif carboxyl-terminal to the zinc finger DNA-binding domain. [(14)C]acetate-labeling experiments demonstrated that AR acetylation by p300 in cultured cells requires the same residues identified in vitro. Point mutation of the AR acetylation site (K632A/K633A) abrogated dihydrotestosterone-dependent transactivation of the AR in cultured cells. Mutation of the p300 CH3 region or the p300/cAMP-response element-binding protein histone acetylase domain reduced ligand-dependent AR function. The identification of the AR as a direct target of histone acetyltransferase co-activators has important implications for targeting inhibitors of AR function.

[The detection and analysis of human papillomavirus in infantile respiratory tract papillomas by PCR/RFLP study]

OBJECTIVE

To study the relationship between human papillomavirus (HPV) and pathological characteristics of the patients with infantile respiratory tract papillomas (IRP).

METHOD

Thirteen cases of infantile respiratory tract papillomas tissue were analysed for Papillomavirus by the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).

RESULT

The amplified products of the HPV-L1 region by PCR by using the consensus primers showed that the presence of HPV was 100 percent. Eight cases(61.5 percent) were positive for HPV6 only. Four cases (30.8 percent) were positive for HPV11 only. One case (7.7 percent) showed the presence of HPV18. None were positive for HPV16, 31, 33, 52, 58.

CONCLUSION

Infantile respiratory tract papillomas are associated with HPV6, 11, 18 infection, but the subtypes of HPV are not associated with clinical pathological characteristics.

The effects of recombinant RA538 and antisense c-myc adenovirus on tumor cells and the molecular mechanism concerned

OBJECTIVE

Compare the biological effects of recombinant RA538 and antisense c-myc adenovirus on human gastric cancer cell line (SGC7901) and explore the molecular mechanism in vitro and in vivo.

METHODS

SGC7901 cells were treated with Ad-RA538, Ad-AS c-myc or Ad-LacZ. MTT, DNA ladder, TUNEL and FCM, RT-PCR, Western blot analysis, the tumorigenicity in nude mice and experimental therapy of the nude mice were used.

RESULTS

Ad-RA538 and Ad-ASc-myc could strongly inhibit cell growth and induce apoptosis of SGC7901 cells. The growth of the Ad-RA538- and Ad-ASc-myc-infected SGC7901 cells were inhibited by 76.3% and 44.1% respectively. The over expression of RA538 and ASc-myc could down-regulate expression of c-myc, bcl-2 and cyclinD1 gene and up-regulate expression of bax gene, but it could not regulate expression of p53, p16, TGase, and ras gene. The tumorigenicity of Ad-RA538 or Ad-ASc-myc in nude mice showed that three of three mice failed to form tumor, compared with Ad-LacZ and parent SGC7901 cells from 7 to 30 days. Experimental therapy of the nude mice bearing subcutaneous tumor of SGC7901 cells showed that intratumor instillation of Ad-RA538 and Ad-ASc-myc inhibited the growth of the tumors. Ad-RA538- and Ad-ASc-myc-treated tumors were inhibited by 60.7% or 68.9% respectively, compared with the tumor injected with Ad-LacZ and mock.

CONCLUSION

The expression of Ad-RA538 and Ad-ASc-myc can inhibit growth and induce apoptosis of gastric cancer cell in vitro and in vivo. RA538 and ASc-myc relate to c-myc, bcl-2, cyclinD1 and bax gene closely and have noticeable biologic effects on gastric cancer cells.

Rationale for directional atherectomy and adjunctive stenting in a patient with non-Q wave myocardial infarction

The development of percutaneous transluminal balloon angioplasty (PTCA) is the greatest revolution in the management of stenotic coronary artery disease. However, PTCA is limited in its application to some specific subgroups of complex lesions such as bifurcational, ostial and plaque burden lesions. For this reason, some new strategies including directional atherectomy (DCA) have been developed as advanced modalities in the treatment of these complex lesions, which if treated by PTCA would certainly yield poor outcomes. We report a case of non-Q wave myocardial infarction resulting from obstruction of the ostium of left anterior descending artery. DCA and adjunctive stenting to the lesion were successfully performed and the patient was discharged uneventfully after the procedure. We suggest that DCA is a striking method and has much merit in the treatment of complex lesions with a high rate of success. In view of consideration of restenosis remains an importantly unresolved problem in percutaneous coronary intervention in specific subgroups of complex lesions. In the future, adequate debulking by mean of DCA in combination with adjunctive stenting which recently emerges as a promising treatment in the prevention of restenosis may provide a more consistent and attractive method for prevention of restenosis in these complex lesions.

Ischaemic myelopathy presenting as Guillain-Barré syndrome

Spinal cord stroke is uncommon. We report a woman presenting with paraesthesia followed by tetraparesis and respiratory failure who was initially diagnosed as having Guillain-Barré syndrome. Subsequent clinical and imaging features supported the diagnosis of an anterior spinal cord infarction. We describe the main clinical and imaging features of this condition.

[Shear bond strength of glass ionomer cement for orthodontic bracket bonding]

OBJECTIVE

The purpose of this study was to investigate the shear bond strength of resin-modified glass ionomer used for orthodontic bracket bonding.

METHODS

30 extracted premolars were evenly divided into two groups. Edgewise brackets (Orsu) were bonded with resin-modified glass ionomer (Advance) in group one and with composite resin (DM) in group two. The shear bond strengths of two materials were tested by material testing machine after 24 hours. The adhesive remnant index was scored after debonding.

RESULTS

The shear bong strengths of resin-modified glass ionomer and composite resin were (6.862 +/- 2.142) MPa and (7.183 +/- 3.205) MPa respectively. There were no statistically significant differences between two groups.

CONCLUSIONS

In vitro bond strength of resin-modified glass ionomer had reached the same level of composite resin. It had the prospect of clinic use.

Sustained mammary gland-directed, ponasterone A-inducible expression in transgenic mice

The ability to regulate temporal- and spatial-specific expression of target genes in transgenic mice will facilitate analysis of gene function and enable the generation of murine models of human diseases. The genetic analysis of mammary gland tumorigenesis requires the development of mammary gland-specific transgenics, which are tightly regulated throughout the adult mammary epithelium. Analysis of genes implicated in mammary gland tumorigenesis has been hampered by mosaic transgene expression and the findings that homozygous deletion of several candidate genes (cyclin D1, Stat5A, prolactin receptor) abrogates normal mammary gland development. We describe the development of transgenic mouse lines in which sustained transgene expression was inducibly regulated, both specifically and homogeneously, in the adult mammary gland epithelium. Transgenes encoding RXRalpha and a chimeric ecdysone receptor under control of a modified MMTV-LTR, which targets mammary gland expression, were used. These transgenic 'receptor' lines were crossed with transgenic 'enhancer' lines in which the ecdysone/RXR binding site induced ligand-dependent expression of transgenic beta-galactosidase. Pharmacokinetic analysis of a highly bioactive ligand (ponasterone A), identified through screening ecdysteroids from local plants, demonstrated sustained release and transgene expression in vivo. This transgenic model with both tightly regulated and homogeneous transgene expression, which was sustained in vivo using ligands readily extracted from local flora, has broad practical applicability for genetic analysis of mammary gland disease.

Computer simulation of sensorless fuzzy control of a rotary blood pump to assure normal physiology

Rotary blood pumps have been considered effective permanently implantable devices. However, control of such pumps is quite complicated. Sensorless control of pump flow is required because no invasive flow or pressure sensors are wanted. Whereas insufficient pump output can cause underperfusion and should be avoided, overpumping may cause ventricular collapse and must be prevented. An intelligent physiologic control algorithm is highly desirable to reach optimal pump output based on physiologic requirements. We present an intelligent physiologic control mechanism for the blood pump allowing it to achieve normal physiology. Sensorless control of pump flow is gained by analysis of the electric motor current and speed. The required pump output flow is chosen based on heart rate, and an intelligent fuzzy logic based control mechanism is developed to adjust the motor input so that the pump output can reach required flow while also preventing the occurrence of ventricular suction or cannular collapse. Computer simulation was carried out, and the results indicate that the proposed algorithms can achieve required pump flow to obtain normal physiology, whereas overpumping can be prevented to provide safe operation.

Changes in genioglossus muscle activity in obstructive sleep apnea patients with and without snore guard

OBJECTIVE

To study the effect of Snore Guard on the genioglossus (GG) muscle activity of obstructive sleep apnea (OSA) patients.

MATERIALS AND METHODS

Fifteen male patients with mild to severe OSA were diagnosed by overnight polysomnographic studies, and were reexamined after using Snore Guard for 2-6 months. The difference in GG muscle activity was then compared.

RESULTS

The overnight GG muscle activity decreased significantly with Snore Guard. The levels of GG muscle activity during awake quiet breath and obstructive sleep apnea were higher than in sleepstate quiet breath without Snore Guard, and significantly decreased with Snore Guard. The increase in GG muscle activity during sleepstate quiet breath with Snore Guard was not statistically significant. The fluctuating GG muscle activity without Snore Guard was effectively improved by treatment with the appliance.

CONCLUSION

The effect of Snore Guard on OSA patients is a mechanical enlargement of upper airway volume. The genioglossus muscle is passive during treatment.

Fish oil modulates macrophage P44/P42 mitogen-activated protein kinase activity induced by lipopolysaccharide

BACKGROUND

Mitogen-activated protein kinase (MAPK) cascades represent a major signal system to transduce extracellular signals into cellular responses. Overactivity of MAPK has been implicated in the development of many diseases, including cancer and sepsis. This study investigated the hypothesis that fish oil altered the membrane phospholipid composition and modulated MAPK activity.

METHODS

RAW 264.7 cells, a mouse macrophage (Mphi) cell line, were grown in eicosapentaenoic acid (EPA)-rich media (114 micromol/L) for 48 hours. Mphi were washed and exposed to Escherichia coli lipopolysaccharide (LPS; 1 microg/mL) for 10 minutes. Both total and activated (phosphorylated) portions of MAPK (P44 and P42) were determined by Western blot assays. AP-1 transcription factor activity was determined by electrophoretic mobility gel shift assays (EMSA). Mphi tumor necrosis factor (TNF) mRNA expression was measured by Northern blot assays.

RESULTS

LPS stimulation induced RAW cell phosphorylation of P44/P42. In contrast, RAW cells grown in EPA-rich media had less P44/P42 activation in the presence of LPS. Total P44/P42 were not affected by EPA or LPS. Similarly, EPA also inhibited AP-1 activity. Inhibition of P44/P42 activity with PD98059 reduced both AP-1 activity and TNF mRNA expression of LPS-stimulated Mphi.

CONCLUSIONS

Our data suggest that fish oil regulates macrophage proinflammatory gene activation, at least in part, by modulating the MAPK activity.

Extensive dissection to the right sinus of Valsalva in coronary angioplasty: case report

Percutaneous transluminal coronary angioplasty was first introduced in 1977 by Gruentzig and now provides the option of nonsurgical revascularization for up to 1/2 of patients who undergo diagnostic catheterization for coronary artery disease. Today, although there have been great improvements in technology and operator experience, complications still occur during coronary angiography and revascularization. Coronary dissection, one of the most frequently occurring complications during angiography and angioplasty, occurs in various forms. However, right coronary dissection and retrograde extension to the aortic sinus of Valsalva is extremely unusual during an interventional procedure. We report such an unusual complication which occurred during balloon angioplasty and which was successfully managed by coronary stenting. This unusual complication may have potential risk of quickly involving the entire aorta, causing acute severe aortic regurgitation, acute myocardial infarction, requiring emergency surgery, and even resulting in death. Therefore, prompt diagnosis and management of this complication are very important.

Analysis of the mandibular position in malocclusion patients

OBJECTIVE

To study the changes of condyle position and occlusion between centric jaw relation (CR) and maximum intercuspation (MI) positions.

METHODS

The power centric registration advocated by Roth was used to take centric relation bite registration for 50 patients (25 Angle Class I, and 25 Angle Class II). Diagnostic models were mounted and analyzed with Panadent articulator and condylar position indicator.

RESULTS

Nearly all patients had CR-MI difference in all three spatial planes. Seventy percent of the sagittal displacement was within 2.0 mm and 87% of the transverse displacement was within 1.0 mm. Movement of most of the condyles was posterior and inferior. Sixty-five percent of the initial contacts in CR occurred on the most posterior molar on one side. When the mandible moved from CR to MI, overbite deepened, overjet decreased, and molar relationship became mesialized. Correlation was found between some variables of condylar displacement and occlusion changes. No significant difference between Angle Class I and Angle Class II patients was observed in condylar position and occlusion changes.

CONCLUSION

The occlusion in centric jaw relation should be analyzed before treatment to reveal the disharmony between occlusion and jaw position.

Cell-cycle dysregulation and the molecular mechanisms of prostate cancer

Prostate cancer is the most common cause of non-cutaneous cancer in men and although frequently latent is the second commonest cause of death. Screening for the disease was historically based on symptoms of urethral obstruction, clinical examination of the prostate gland and serum measurements of prostate specific antigen. As prostate cancer growth in the early stages is enhanced by androgens, the mainstay of therapy has been androgen ablation by pharmaco-therapeutic or surgical means. The subsequent development of androgen therapy resistant prostate cancer in many patients, for whom therapeutic options remain limited, has led researchers to focus attention on understanding the molecular genetics of prostate cancer. The array of genetic abnormalities observed in prostate tumors, which include changes in components of the cell cycle, suggest the disease is quite heterogeneous and may require further sub-classification based on genetic markers. Such analyses may lead to identification of relevant new prognostic and therapeutic indicators. The advent of transgenic mouse models of prostate cancer may provide a critical tool for the implementation of rational genetic based therapeutics and alternate drug design.

A monoclonal antibody directed against an autoimmune epitope on the human beta1-adrenergic receptor recognized in idiopathic dilated cardiomyopathy

A monoclonal antibody (MAb M16) was obtained by immunizing Balb/C mice with free peptide H26R, corresponding to the second extracellular loop of the human beta1-adrenergic receptor (beta1AR), against which functional autoantibodies have been detected in patients with idiopathic dilated cardiomyopathy. The MAb was found to be of IgG2b type and directed against a conformational epitope, encompassing the sequence recognized by the human autoantibodies. BIAcore measurements yielded an equilibrium constant of 6.5 X 10(7) M1 with an association rate constant (kon) of 6.5 X 10(4) M(-1) sec(-1) and a dissociation rate constant (koff) of 1.0 X 10(-3) sec(-1). It immunoprecipitated only poorly the solubilized beta1AR of Sf9 cell membranes. Functionally, the MAb was capable of not only reducing the number of the maximal binding sites to the beta1-adrenergic receptor of transfected Sf9 cell membranes, but also of displaying a positive chronotropic effect on cultured neonatal rat cardiomyocytes. These properties, which the MAb shares with the human autoantibodies, makes it an interesting tool for passive transfer studies in mice.

Cephalometric comparisons between Chinese and Caucasian patients with obstructive sleep apnea

The purpose of this study was to compare two groups of adult men from different ethnic backgrounds and with obstructive sleep apnea; they were selected by matching age, gender, skeletal pattern, body mass index, and respiratory disturbance index. Pretreatment cephalometric radiographs and overnight polysomnograms of 30 Chinese and 43 Caucasian patients with Class II, Division 1 malocclusions were analyzed to investigate if there were craniofacial and upper airway structural differences between the two ethnic groups. The Chinese group, when compared with the group of Caucasian patients, revealed more severe underlying craniofacial skeletal discrepancies with significantly smaller maxilla and mandibles, more severe mandibular retrognathism, proclined lower incisors, increased total and upper facial heights, and steeper and shorter anterior cranial bases. However, no significant differences were found between the two groups in posterior facial height, ratio of upper to lower anterior facial height, and the position of hyoid bone, maxilla, and upper incisors. With regard to soft tissue and upper airway measurements, there were no significant ethnic differences in tongue and soft palate size, vertical length of oropharynx, and anteroposterior dimensions of the upper airway at most of the levels except for a larger super-posterior airway space, a larger nasopharynx and oropharynx cross-sectional area, and a smaller tongue height in the Chinese group. We conclude that there are a number of craniofacial and upper airway structures that differ between the two ethnic groups that may be relevant to the treatment of obstructive sleep apnea in various ethnic groups.

Direct angioplasty of totally occluded left main coronary artery in acute myocardial infarction complicated by cardiogenic shock: report of two cases and literature review

Acute total occlusion of the left main coronary artery is usually characterized by a rapid course of deterioration that challenges therapeutic intervention. Unlike subtotal occlusion of the left main coronary artery, acute total occlusion of the left main coronary artery is extremely rare and has a grave prognosis. Most patients with this problem die suddenly or go into cardiogenic shock. Direct percutaneous transluminal coronary angioplasty (PTCA) was performed on 2 patients, both suffering from cardiogenic shock due to acute total occlusion of the left main coronary artery. Both patients underwent coronary artery bypass surgery subsequently. One patient, who had substantial intercoronary collaterals, remained asymptomatic at 31 months of follow-up. The other, who had no intercoronary collateral circulation, expired 3 days after coronary artery bypass surgery. We conclude that direct PTCA to the acutely occluded unprotected left main coronary artery in cardiogenic shock patients is a potentially life-saving procedure, and the presence or absence of collaterals from the dominant right coronary artery will influence the clinical outcome.

[Arsenic trioxide induces human tumor cell apoptosis and G2 + M arrest whereas causes HPV16 DNA immortalized cervical epithelial cells G1 block]

OBJECTIVE

To investigate whether As2O3 induces tumor cell apoptosis and cell cycle arrest.

METHODS

DNA agarose gel electrophoresis, flowcytometry analysis, RT-PCR, and Western blot.

RESULTS

As2O3 induced G2 + M arrest of tumor cells such as GLC-82, MGC-803, SGC-7901, Eca109 and HeLa cells before inducing apoptosis and decreased c-myc gene expression, whereas caused G1 block of HPV16 DNA immortalized cervical epithelial HCE16/3 cells and did not affect c-myc expression.

CONCLUSIONS

As2O3 caused apoptosis was related with cell cycle arrest. However, the phase of arrest of tumor cells was different from the pre-tumor cell HCE16/3 cells, which could be related to the change of c-myc gene expression.

Myocardial oxygen consumption modulates adenosine formation by canine right ventricle in absence of hypoxia

Myocardial adenosine formation varies with myocardial oxygen consumption (MVO(2)), but whether concurrent hypoxia is required for adenosine formation is uncertain. Changes in right coronary (RC) perfusion pressure (RCP) produce directionally similar alterations in right ventricular (RV) MVO(2)and in RC venous P O(2)(P(v)O(2)), an index of myocardial P O(2). RCP was varied in 10 anesthetized, open chest dogs to determine if, under these conditions, RV formation of adenosine would increase with MVO(2)in absence of myocardial hypoxia. Dialysis probes were implanted in the mid myocardium of RV free wall for collecting dialysate samples for HPLC analyses to estimate interstitial adenosine and other purines. Coronary venous blood was sampled from a superficial vein draining the RC artery (RCA) perfusion territory. At 115+/-3 mmHg baseline RCP, RC blood flow (RCBF)=0.51+/-0.04 ml/min/g, MVO(2)=4.6+/-0.5 ml/min/100 g, P(v)O(2)=34+/-1.5 mmHg, and dialysate adenosine=0. 27+/-0.03microM. When RCP was lowered to 61+/-1 mmHg by adjusting an occluder on the proximal RCA, RCBF decreased to 0.36+/-0.03 ml/min/g, MVO(2)fell to 3.7+/-0.4 ml/min/100 g, lactate uptake remained positive, P(v)O(2)fell to 30+/-1.7 mmHg, and dialysate adenosine decreased to 0.20+/-0.03microM. Reactive hyperemia of 1.25+/-0.13 ml/min/g was observed when the RCA constriction was released, although dialysate adenosine had fallen. When RCP was elevated to 164+/-2 mmHg by inflating a balloon catheter in the descending aorta, RCBF increased to 0.70+/-0.06 ml/min/g, MVO(2)increased to 5.8+/-1. 0 ml/min/100 g, P(v)O(2)rose to 39+/-2.3 mmHg, and dialysate adenosine increased to 0.33+/-0.04microM. These data indicate that (1) RV oxygen demand varies with RCP; (2) if RV ischemia is absent, myocardial adenosine formation is modulated by MVO(2), with no requirement for hypoxia; (3) pressure-flow autoregulation is relatively ineffective in the RC circulation, where adenosine does not mediate and may even blunt autoregulation.

Cyclooxygenase 2 (COX-2) gene activation is regulated by cyclic adenosine monophosphate

Prostaglandin E2 production by tissue-fixed macrophages (Mphi) after severe injury contributes to an enhanced susceptibility to infection and sepsis. The purpose of this study was to investigate the effect of cyclic adenosine monophosphate (cAMP) on prostaglandin (PGE2) production and cyclooxygenase II (COX-2) gene activation in LPS-stimulated macrophages (Mphi). RAW264.7 cells, a mouse Mphi cell line, were exposed to various concentrations of dibutyryl cAMP +/- lipopolysaccharide (10 microg/mL) stimulation. Total Mphi ribonucleic acid (RNA) was harvested for the determination of COX-2 messenger RNA (mRNA) with mouse complementary deoxyribonucleic acid (cDNA) by Northern blot assay. Mphi supernatant was collected for the measurement of tumor necrosis factor (TNF) by L929 bioassay and PGE2 by enzyme-linked immunosorbent assay (ELISA), respectively. Mphi NFkappaB activity was determined by electrophoretic mobility shift assays (EMSA). Dibutyryl cAMP significantly inhibited TNF production by LPS-stimulated Mphi. Dibutyryl cAMP (1 mM) alone induced PGE2 production. Dibutyryl cAMP (100 microM and 1 mM) also augmented PGE2 production by LPS-stimulated Mphi. Dibutyryl cAMP had similar effect on Mphi COX-2 mRNA expression and NFkappaB activity. Our data demonstrate that cAMP modulates Mphi TNF production and upregulates COX-2 gene and PGE2 production.

Unexpected loss of bipolar pacing with implanted dual chamber pacemakers

Bipolar leads are most commonly used in the current practice of pacemaker therapy. In our study of 124 patients implanted with Guidant/Cardiac Pacemakers (CPI) Vigor dual chamber pacemakers, 5 patients had unexpectedly abrupt increases in bipolar lead impedance and pacing threshold 2 weeks to 18 months postimplantation without changes in sensing function. With the lead configuration reprogrammed to unipolar, the lead impedance and pacing threshold were restored to appropriate ranges. The changes in bipolar lead parameters can be caused by the CPI's "Quick Connect" (QC1) header lead system incorporated in these pacemakers.

Cyclin D1 is required for transformation by activated Neu and is induced through an E2F-dependent signaling pathway

The neu (c-erbB-2) proto-oncogene encodes a tyrosine kinase receptor that is overexpressed in 20 to 30% of human breast tumors. Herein, cyclin D1 protein levels were increased in mammary tumors induced by overexpression of wild-type Neu or activating mutants of Neu in transgenic mice and in MCF7 cells overexpressing transforming Neu. Analyses of 12 Neu mutants in MCF7 cells indicated important roles for specific C-terminal autophosphorylation sites and the extracellular domain in cyclin D1 promoter activation. Induction of cyclin D1 by NeuT involved Ras, Rac, Rho, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38, but not phosphatidylinositol 3-kinase. NeuT induction of the cyclin D1 promoter required the E2F and Sp1 DNA binding sites and was inhibited by dominant negative E2F-1 or DP-1. Neu-induced transformation was inhibited by a cyclin D1 antisense or dominant negative E2F-1 construct in Rat-1 cells. Growth of NeuT-transformed mammary adenocarcinoma cells in nude mice was blocked by the cyclin D1 antisense construct. These results demonstrate that E2F-1 mediates a Neu-signaling cascade to cyclin D1 and identify cyclin D1 as a critical downstream target of neu-induced transformation.

Overexpression of Bcl-2 partly inhibits apoptosis of human cervical cancer SiHa cells induced by arsenic trioxide

OBJECTIVE

To study the biological effect of arsenic trioxide (As2O3) on human cervical cancer SiHa cells and SiHa cells overexpressing bcl-2 gene.

METHODS

SiHa cells with overexpression of Bcl-2 (SiHa-Bcl2 cells) were established by transfecting SiHa cells with Bcl-2 expression vector. The sensitivities of SiHa and SiHa-Bcl2 cells to As2O3 were determined using MTT (Thiazolyl blue) reduction and colony forming ability assay, morphological analysis, flow cytometric analysis, DNA agarose gel electrophoresis, in situ cell death detection (TUNEL), Northern blot, RT-PCR and Western blot.

RESULTS

As2O3 inhibited the growth of SiHa cells and induced G2/M arrest and apoptosis of the cells. RT-PCR and Western blot analysis revealed that As2O3 induced SiHa cell apoptosis possibly via inhibiting the expression of HPV16 E7 and decreasing the expression of c-myc. However, we found that SiHa-Bcl2 cells partly resisted As2O3 induced apoptosis, which might be related to the prevention of the down-regulation of HPV16 E7 and c-myc gene expression. Nevertheless, As2O3 at a high concentration could still induce apoptosis of SiHa-Bcl2 cells mainly via decreasing Bcl-2 expression and slightly inhibiting viral gene expression.

CONCLUSION

As2O3 is an inducer of the apoptosis of human cervical carcinoma cells and the cells overexpressing Bcl-2 can partly resist As2O3 induced apoptosis, but the exact mechanism is unclear.

[Expression of transforming growth factor-beta 1 mRNA and osteopontin mRNA in UMR-106 cells under mechanical stimulation]

OBJECTIVE

To investigate the effects of the mechanical stretching on the expression of osteopontin (OPN) mRNA and transforming growth factor-beta 1 (TGF beta 1) mRNA in a rat osteosarcoma cell line (UMR-106), and to unveil the cellular mechanism of mechanical force-induced bone remodeling.

METHODS

An apparatus was designed and fabricated by which force was loaded onto the cultured cells in vitro. Digoxin-labeled cDNA probes were used for in situ hybridization in combination with image analysis technique to relatively quantify the intensities of the hybridization signals.

RESULTS

Various magnitudes and durations of the mechanical stretching did exert different influences on the intensities of the mRNAs' expression. Of all the combinations, the low tension/frequency group showed the most remarkable alteration of TGF-beta 1, as increased from 0.0899 to 0.1756 (P < 0.01). Some putative relations lay between the expressions of the OPN mRNA and the TGF-beta 1 mRNA.

CONCLUSION

The mechanical stretching can inevitably influence the expression of OPN mRNA and TGF-beta 1 mRNA. The beneficial alteration obtained in using low tension/frequency action mode suggests and verifies the use of relatively constant and light force to move teeth in clinical orthodontics.

[Effect of human plasma HDL on the HDL receptors of plasma membranes of cholesterol-fed rabbit]

Atherosclerosis(As) rabbit model was developed by high-cholesterol feeding for 12 weeks. The rabbits were injected intravenously with human plasma HDL preparation per week, and then the effects of HDL on the lipids contents of serum, liver and bile nd the activity of HDL receptors on liver plasma membranes of cholesterol-fed rabbit were investigated. The results showed that HDL preparation had no effect on decreasing the lipids contents of serum, but it could low down the lipid depositions in liver, and promote the excretion of lipids from bile. The value of Bmax of HDL receptor showed decreasing trendy and the value of Kd showed increasing trendy in cholesterol-fed rabbits. In HDL-treated rabbits, the value of Bmax increased significantly as compared with that of normal group(P < 0.05), but the value of Kd showed no difference. The results suggested that human plasma HDL could enhance the activity of HDL receptors on the liver plasma membranes of cholesterol-fed rabbit.

Activation of the cyclin D1 gene by the E1A-associated protein p300 through AP-1 inhibits cellular apoptosis

The adenovirus E1A protein interferes with regulators of apoptosis and growth by physically interacting with cell cycle regulatory proteins including the retinoblastoma tumor suppressor protein and the coactivator proteins p300/CBP (where CBP is the CREB-binding protein). The p300/CBP proteins occupy a pivotal role in regulating mitogenic signaling and apoptosis. The mechanisms by which cell cycle control genes are directly regulated by p300 remain to be determined. The cyclin D1 gene, which is overexpressed in many different tumor types, encodes a regulatory subunit of a holoenzyme that phosphorylates and inactivates PRB. In the present study E1A12S inhibited the cyclin D1 promoter via the amino-terminal p300/CBP binding domain in human choriocarcinoma JEG-3 cells. p300 induced cyclin D1 protein abundance, and p300, but not CBP, induced the cyclin D1 promoter. cyclin D1 or p300 overexpression inhibited apoptosis in JEG-3 cells. The CH3 region of p300, which was required for induction of cyclin D1, was also required for the inhibition of apoptosis. p300 activated the cyclin D1 promoter through an activator protein-1 (AP-1) site at -954 and was identified within a DNA-bound complex with c-Jun at the AP-1 site. Apoptosis rates of embryonic fibroblasts derived from mice homozygously deleted of the cyclin D1 gene (cyclin D1(-/-)) were increased compared with wild type control on several distinct matrices. p300 inhibited apoptosis in cyclin D1(+/+) fibroblasts but increased apoptosis in cyclin D1(-/-) cells. The anti-apoptotic function of cyclin D1, demonstrated by sub-G(1) analysis and annexin V staining, may contribute to its cellular transforming and cooperative oncogenic properties.

[Separation and selection of salivary adhesion receptors of Streptococcus mutans to tooth surface]

OBJECTIVE

To select and purify salivary receptors of Streptococcus mutans from experimental salivary acquired pellicle.

METHODS

Experimental salivary acquired pellicle (SAP) was performed by coating hydroxyapatite (HA) with whole saliva. Then SAP was washed from HA by 1 mol/L NaCl and 0.5 mol/L phosphate buffer sequentially. The proteins were further separated by chromatography of Sephadex G75 and DEAE-Sephadex A25. Receptors of Streptococcus mutans were selected by bacterial adhesion test and competitive inhibition adhesion test. Identification was performed by PAGE, SDS-PAGE, IP-PAGE and detection of amylase activity and inmunodifusion test.

RESULTS

IgA degraded fragments, a protein of 13 kD and amylases were the receptors of S. mutans. The first two only promote the adhesion but the amylases can both promote and inhibit S. mutans adhesion.

CONCLUSION

The adhesion of S. mutans to tooth surface is a result of interaction between adhesins of S. mutans and multiple salivary receptors.