[Clinical application and evaluation of polymerase chain reaction-microwell plate hybridization assay in the detection of Mycobacterium tuberculosis]

OBJECTIVE

To evaluate the clinical application and feasibility of polymerase chain reaction-microwell plate hybridization assay in the detection of Mycobacterium tuberculosis.

METHODS

1130 specimens with strong suspicion for mycobacterium tuberculosis were collected from the hospitals and were detected by fast bacilli stain, culture, PCR-electrophoresis and PCR-microwell plate hybridization respectively. The laboratory results were analyzed in combination with the symptoms and signs of patients and the observations on treatment. Also detected were 100 samples from the clinically evidenced non-tuberculosis patients.

RESULTS

In the 100 samples collected from the patients without tuberculosis, the PCR-hybridization method and culture method did not detect Mycobacterium tuberculosis, but the fast bacilli stain method and PCR-electrophoresis method brought out one and two false-positive results respectively. The results of testing the 1030 clinical samples which probably contained Mycobacterium tuberculosis demonstrated that the PCR-hybridization method had the highest positive rate (481/1030) among the four methods, and the positive rates of the other three methods were PCR-electrophoresis (406/1030), culture (365/1030) and fast bacilli stain (256/1030) in proper order. The chi-square test showed that there were significant difference between the PCR-hybridization method and the other three methods respectively (P < 0.0083 or P < 0.0017).

CONCLUSION

PCR-Hybridization method is specific, sensitive, accurate and fast in detecting mycobacterium tuberculosis; it is worthy to be used clinically.

Role of calcineurin in angiotensin II-induced cardiac myocyte hypertrophy of rats

OBJECTIVE

The present study investigated the role of calcineurin in angiotensin II(AngII) -induced cardiac myocyte hypertrophy of rats.

METHOD

The primary cardiac myocytes were cultured under the standard conditions. The calcineurin activity in AngII-treated cardiomyocytes was tested by using PNPP; protein synethsis rate was assessed by 3H-leucine incorporation; atrial natriuretic factor(ANF) mRNA level was determined by Northern blot analysis. Cell viability was estimated by lactate dehydrogenase (LDH) levels in cultured medium and by dyed cell numbers.

RESULT

After stimulation of 10, 100 and 1 000 nmol/L of AngIi, calcineurin activities in the cardiomyocytes were increased by 13%, 57% (P < 0.05) and 228% (P < 0.01) respectively, compared with control group. Cyclosporin A(CsA), a specific inhibitor of calcineurin, markedly inhibited the calcineurin activity and decreased the 3H-leucine incorporation in AngII-treated cardiomyocytes in a dose-dependent manner. It was also found that CsA slightly reduced the mRNA level of ANF gene in AngII-stimulated cardiomyocytes.

CONCLUSION

During AngII-induced cardiac myocyte hypertrophy, calcineurin signal pathway is activated, and inhibition of the pathway can attenuate AngII-induced cardiac myocyte hypertrophy, which suggests that the calcineurin signal pathway may play an important role in AngII-induced myocardial hypertrophy of rats.

[Individual studies of parent-offspring similarity in Class II division 1 malocclusion]

OBJECTIVE

To study the parent-offspring similarity of class II division 1 malocclusion.

METHODS

On the basis of family units, the polygonic curves and superimposed graphs of parents with those of the offspring were compared.

RESULTS

(1) Craniofacial structure of most parents of the class II division 1 patients have class II convex tendency. (2) The curves of the offspring resemble one or two of the parent's in 84% of the families, and the resemblance mainly concentrates in skeleton.

CONCLUSIONS

(1) Class II division 1 malocclusion is characterized by familial aggregativity. (2) High probability of heredity exists in parent-offspring similarity, and we believe that hereditary factors dominate in skeletal area while in dental area there is a higher probability that environmental factors dominate.

NF-kappaB and cell-cycle regulation: the cyclin connection

The cyclins are a family of proteins that are centrally involved in cell cycle regulation and which are structurally identified by conserved "cyclin box" regions. They are regulatory subunits of holoenzyme cyclin-dependent kinase (CDK) complexes controlling progression through cell cycle checkpoints by phosphorylating and inactivating target substrates. CDK activity is controlled by cyclin abundance and subcellular location and by the activity of two families of inhibitors, the cyclin-dependent kinase inhibitors (CKI). Many hormones and growth factors influence cell growth through signal transduction pathways that modify the activity of the cyclins. Dysregulated cyclin activity in transformed cells contributes to accelerated cell cycle progression and may arise because of dysregulated activity in pathways that control the abundance of a cyclin or because of loss-of-function mutations in inhibitory proteins.Analysis of transformed cells and cells undergoing mitogen-stimulated growth implicate proteins of the NF-kappaB family in cell cycle regulation, through actions on the CDK/CKI system. The mammalian members of this family are Rel-A (p65), NF-kappaB(1) (p50; p105), NF-kappaB(2) (p52; p100), c-Rel and Rel-B. These proteins are structurally identified by an amino-terminal region of about 300 amino acids, known as the Rel-homology domain. They exist in cytoplasmic complexes with inhibitory proteins of the IkappaB family, and translocate to the nucleus to act as transcription factors when activated. NF-kappaB pathway activation occurs during transformation induced by a number of classical oncogenes, including Bcr/Abl, Ras and Rac, and is necessary for full transforming potential. The avian viral oncogene, v-Rel is an NF-kappaB protein. The best explored link between NF-kappaB activation and cell cycle progression involves cyclin D(1), a cyclin which is expressed relatively early in the cell cycle and which is crucial to commitment to DNA synthesis. This review examines the interactions between NF-kappaB signaling and the CDK/CKI system in cell cycle progression in normal and transformed cells. The growth-promoting actions of NF-kappaB factors are accompanied, in some instances, by inhibition of cellular differentiation and by inhibition of programmed cell death, which involve related response pathways and which contribute to the overall increase in mass of undifferentiated tissue.

Endogenous indoles as novel polyamine site ligands at the N-methyl-D-aspartate receptor complex

High-throughput ligand displacement screens of a series of endogenous indoles revealed that tryptamine, serotonin and 5-methoxytryptamine readily displace [3H]spermidine and [3H]MK-801 from their respective binding sites in rat brain homogenate. These data, coupled with their potent inhibition of spermidine-potentiated [3H]MK-801 binding, suggest that certain endogenous indoles may act as ligands to one or more polyamine binding sites in the brain, including those on the N-methyl-D-aspartate receptor complex.

Cytogenetic analysis in 61 couples with spontaneous abortions

OBJECTIVE

To examine the relationship between spontaneous abortion and chromosomal abnormalities.

METHODS

Couples who had one or more consecutive spontaneous abortions and had normal genitals were enrolled for cytogenetic karyotype analysis.

RESULTS

In the 61 couples, the detected incidence was 11.5%, with five Robertsonian translocations, one reciprocal translocation, and one pericentric inversion of chromosome 7.

CONCLUSION

Chromosomal abnormalities may play an important role in fetal wastage.

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.