Progesterone Prevents High-Grade Serous Ovarian Cancer by Inducing Necroptosis of p53-Defective Fallopian Tube Epithelial Cells

High-grade serous ovarian carcinoma (HGSOC) originates mainly from the fallopian tube (FT) epithelium and always carries early TP53 mutations. We previously reported that tumors initiate in the FT fimbria epithelium because of apoptotic failure and the expansion of cells with DNA double-strand breaks (DSB) caused by bathing of the FT epithelial cells in reactive oxygen species (ROSs) and hemoglobin-rich follicular fluid (FF) after ovulation. Because ovulation is frequent and HGSOC is rare, we hypothesized that luteal-phase progesterone (P4) could eliminate p53-defective FT cells. Here we show that P4, via P4 receptors (PRs), induces necroptosis in Trp53^-/- mouse oviduct epithelium and in immortalized human p53-defective fimbrial epithelium through the TNF-α/RIPK1/RIPK3/MLKL pathway. Necroptosis occurs specifically at diestrus, recovers at the proestrus phase of the estrus cycle, and can be augmented with P4 supplementation. These results reveal the mechanism of the well-known ability of progesterone to prevent ovarian cancer.

Inducible nitric oxide synthase mediates MG132 lethality in leukemic cells through mitochondrial depolarization

Proteasomes are highly expressed in rapidly growing neoplastic cells and essential for controlling the cell cycle process and mitochondrial homeostasis. Pharmacological inhibition of the proteasome shows a significant anticancer effect on hematopoietic malignancies that is usually associated with the generation of reactive oxygen species. In this study, we comprehensively investigated the role of endogenous oxidants in various cellular events of K562 leukemic cells in response to treatment with MG132, a proteasome inhibitor. MG132 at 1.4 µM potently triggered G2/M arrest, mitochondrial depolarization, and apoptosis. By such treatment, the protein level of inducible nitric oxide synthase (iNOS) was doubled and cellular oxidants, including nitric oxide, superoxide, and their derivatives, were increasingly produced. In MG132-treated cells, the increase in iNOS-derived oxidants was responsible for mitochondrial depolarization and caspase-dependent apoptosis, but was insignificant in G2/M arrest. The amount of iNOS was negatively correlated with that of manganese superoxide dismutase (MnSOD). Whereas iNOS activity was inhibited by aminoguanidine, cellular MnSOD levels as well as mitochondrial membrane potentials were upregulated, and consequentially G2/M arrest and apoptosis were thoroughly reversed. It is suggested that cells rich in functional mitochondria possess improved proteasome activity, which antagonizes the cytotoxic and cytostatic effects of MG132. In contrast to iNOS, endothelial NOS-driven cGMP-dependent signaling promoted mitochondrial function and survival of MG132-stressed cells. In conclusion, the functional interplay of proteasomes and mitochondria is crucial for leukemic cell growth, wherein iNOS plays a key role.

Ga-67 scan to detect intra-abdominal infection in patients after colorectal surgery

PURPOSE

Intra-abdominal infection is still an important issue in colorectal surgery. The Ga-67 scan is relatively inexpensive, but the delay in diagnosis and the intense physiologic bowel activity are considerable drawbacks to its use in abdominal investigations. In this study, the authors performed 24-hour Ga-67 scans and read the images with the surgeon to detect abdominal infection in patients who underwent colorectal surgery.

METHODS

Sixty-one patients who underwent colorectal surgery were enrolled in this study. Ga-67 scintigraphy was performed 24 hours, and later as needed, after the injection of 111 MBq (3 mCi) Ga-67 citrate. All scans were interpreted together by a nuclear medicine specialist and the surgeon. The intensity of Ga-67 uptake was recorded as grade 0: no uptake; grade 1: less than liver uptake; grade 2: equal to liver uptake; or grade 3: greater than liver uptake. When the intensity of Ga-67 uptake was equal to or greater than grade 2, the pattern of Ga-67 uptake was classified as changing or unchanging. A positive Ga-67 scan was defined as having an intensity of grade 2 or 3 with an unchanging pattern.

RESULTS

Nineteen abdominal infections were diagnosed, all by Ga-67 scans, for a diagnostic sensitivity rate of 100%. Of the 42 patients with no intra-abdominal infection, only 2 had positive Ga-67 scans. This resulted in a specificity rate of 95.2%. The overall accuracy of the Ga-67 scan in the detection of intra-abdominal infection after colorectal surgery was 96.7%.

CONCLUSIONS

The Ga-67 scan is useful for detecting intra-abdominal infection after colorectal surgery. Reading the images with the surgeon and using a lateral view can decrease the false-positive rate. A negative Ga-67 scan can rule out intra-abdominal infection, whereas a positive Ga-67 scan indicates the need for further patient evaluation after colorectal surgery.

Abdominal abscesses in patients having surgery: an application of Ga-67 scintigraphic and computed tomographic scanning

PURPOSE

Early detection of occult abscesses is important in patients with persistent fever after colorectal surgery. In this study, the authors evaluated the relative merits of computed tomographic (CT) and Ga-67 scans in the detection of intra-abdominal abscesses in patients who had just undergone colorectal surgery.

MATERIALS AND METHODS

Thirty-four patients who underwent colorectal surgery were enrolled in the study. Ga-67 and CT scans were obtained in all patients. Ga-67 scintigraphy was performed 24 hours, and later as needed, after the injection of 111 MBq (3 mCi) Ga-67 citrate.

RESULTS

Intra-abdominal abscesses were diagnosed in 16 of the 34 (47%) patients who had colorectal surgery. For CT scans, the overall accuracy, sensitivity, and specificity rates were 97.1%, 93.7%, and 100%, respectively. For the Ga-67 scans, the diagnostic accuracy, sensitivity, and specificity rates were 91.2%, 100%, and 95.2%, respectively. In addition, the whole-body Ga-67 scans successfully detected two cases of extra-abdominal infection, one case of pneumonia, and one case of cellulitis.

CONCLUSIONS

Computed tomographic and Ga-67 scans offer complementary information and play an important role in the investigation of sources of infection in patients after colorectal surgery.

BMK1 mediates growth factor-induced cell proliferation through direct cellular activation of serum and glucocorticoid-inducible kinase

Activation of the mammalian mitogen-activated protein kinase known as BMK1 is required for growth factor-induced cell proliferation. To understand the mechanism by which BMK1 mediates this cellular response, this kinase was used as bait in a yeast two-hybrid-based library screening. Here, we report the identification of serum and glucocorticoid-inducible kinase (SGK) as a cellular protein that physically interacts with BMK1. During growth factor-induced cell stimulation, BMK1 activates SGK by phosphorylation at serine 78. This BMK1-mediated phosphorylation event is necessary for the activation of SGK and, more importantly, for cell proliferation induced by growth factors.

Uptake of gallium-67 citrate in clean surgical incisions after colorectal surgery

Non-specific accumulation of gallium-67 citrate (gallium) in uncomplicated surgical incisions is not uncommon. It is important to know the normal pattern of gallium uptake at surgical incision sites in order to properly interpret the gallium scan when investigating possible wound infection in patients who have undergone abdominal surgery. We studied 42 patients without wound infection after colorectal surgery and performed gallium scans within 40 days after surgery. Patients were divided into three groups according to the interval between the operation and the scan. In group A (26 patients) gallium scan was performed within 7 days after surgery, in group B (8 patients) between 8 and 14 days after surgery, and in group C (8 patients) between 15 and 40 days after surgery. Our data showed that in group A, 61.5% had gallium accumulation at the surgical incision site. In group B, 50% had accumulation of gallium at the surgical incision site, while in group C only one patient (12.5%) showed gallium uptake. It is concluded that the incidence of increased gallium uptake at clean surgical incision sites is high after colorectal surgery. Nuclear medicine physicians should bear in mind the high incidence of non-specific gallium uptake at such sites during the interpretation of possible wound infection in patients after colorectal surgery.

Value of 18F-fluoro-2-deoxyglucose positron emission tomography in the evaluation of recurrent colorectal cancer

To evaluate the clinical value of positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) in recurrent colorectal cancer, the records of 33 patients who underwent 34 FDG-PET scans were reviewed and compared with computed tomography (CT) and carcinoembryonic antigen (CEA). The final diagnosis was based on operative, histopathological findings or clinical follow-up > 1 year. FDG-PET detected all 15 patients with recurrent diseases (9 local recurrences, 4 lymphatic metastases, 2 hepatic metastases and 8 pulmonary metastases) and 1 primary lung cancer. However, there were 3 false positive cases. The overall sensitivity and specificity of FDG-PET were 100% and 83%, respectively. The sensitivity and specificity of CEA were 33% and 86%, respectively, for detecting recurrent colorectal cancer. Abdominal CT had a sensitivity and specificity of 78% and 61% for detecting local recurrence and detected one lymphatic and one hepatic metastasis. In conclusion, the FDG-PET was more accurate than CT and CEA for the detection of recurrent colorectal cancer. In addition, it accurately detected distant metastases or occult secondary malignancy and may affect clinical management.

Surgical treatment for rectal prolapse

BACKGROUND

The problem of full-thickness rectal prolapse is formidable, with no clear predominant treatment of choice. Several operations have been proposed to correct rectal prolapse which can be divided into transabdominal and perineal procedures.

METHODS

From September 1982 to October 1999, 32 patients with rectal prolapse were treated with surgical procedures. There were 16 males and 16 females with a mean age of 58.3 years (Range 17-89). Forteen patients received rectopexy procedure, 6 patients received sigmoidectomy, 6 patients received perineal rectosigmoidectomy, 1 patient received Delorme procedure, 1 patient received Thiersch procedure and 4 patients received laparoscopic-assisted sigmoidectomy. The median follow up times were 7.5 years.

RESULTS

In the rectopexy group, complication occurred in one patient (7.1%) and one patient recurred (7.1%). In the sigmoidectomy group, there were no complication but one patient recurred (10%). In the perineal rectosigmoidectomy group, there were no complication, but one patient recurred (16.7%). The total complication rate were 3.1% and total recurrence rate were 9.3%.

CONCLUSIONS

Although, the best operation for rectal prolapse remains a controversial subject, we believe that laparoscopic-assisted sigmoidectomy offers a promising new option for the treatment of rectal prolapse.

Role of BMK1 in regulation of growth factor-induced cellular responses

Big mitogen-activated protein kinase (MAPK) 1 (BMK1), also known as ERK5, is a recently identified member of the mammalian MAPK family. Cellular stimulation of BMK1 is induced in response to growth factors, oxidative stress, and hyperosmolar conditions. Specific members of the myocyte enhancer factor 2 family of transcription factors that regulate growth factor-induced early gene expression have been identified as direct downstream targets of BMK1 activity. Recent studies have shown that growth factors of the epidermal growth factor family mediate the sequential activation of a kinase cascade consisting of MAPK kinase kinase 3, MAPK kinase 5, and BMK1. Most importantly, the activation of this signal transduction pathway has been shown to be required for growth factor-mediated cell proliferation and cell-cycle progression. Collectively, these studies establish BMK1 as an important regulator of growth factor-induced cellular responses.

Sick sinus syndrome in a patient with single coronary artery anomaly

Single coronary artery anomaly is very rare. The reported manifestations include angina pectoris and congestive heart failure. Here we describe a case of single coronary artery anomaly presenting as sick sinus syndrome, which has no literature precedence. A 47-year-old woman had complained of intermittent dizziness for years. A Holter electrocardiogram showed sinus bradycardia and junctional or ventricular rhythm with a maximal ventricular pause of up to 3.2 seconds. Electrophysiologic study revealed prolonged corrected sinus nodal recovery time. Coronary angiography showed that the left anterior descending artery had a long course with a side branch originating from the proximal part and coursing anteriorly to the territory of the proximal portion of the right coronary artery. The sinus node is usually supplied by the sinoatrial branch via the right coronary artery. Aortography showed that the right coronary artery ostium was absent. A permanent pacemaker was implanted and the patient was discharged in good condition. The present case suggests that coronary artery anomaly may lead to compromised blood supply to the sinus node, and hence sick sinus syndrome.

Effect of atrial fibrillation on pulmonary venous flow patterns assessed by Doppler transesophageal echocardiography

STUDY OBJECTIVES

To investigate the effect of atrial fibrillation (AF) on pulmonary venous flow (PVF) patterns in a cohort with nonrheumatic AF.

DESIGN AND SETTINGS

A prospective and controlled study undertaken at a tertiary referral medical center.

PATIENTS AND MEASUREMENTS

The echocardiographic parameters of left superior PVF as assessed by Doppler transesophageal echocardiography in 40 patients with chronic AF (group 1) were compared to those of 33 volunteers with sinus rhythm (group 2) and well-matched baseline characteristics.

RESULTS

: All group 1 patients presented with single systolic forward flow (SFF) patterns. In contrast, single and double SFF patterns were found equally in group 2. With regard to reverse flow (RF), most group 1 patients (33 of 40) had an early systolic RF and none had atrial RF; however, most group 2 subjects (29 of 33) had an atrial RF. Some of the group 1 patients (17%) had a late systolic RF in the absence of significant mitral regurgitation. In group 1, the SFF appeared later and disappeared earlier than in group 2. The mean systolic peak velocity and time-velocity integral (TVI) of the SFF were significantly lower in group 1 compared to group 2. The diastolic peak velocity and TVI were not significantly different between groups.

CONCLUSIONS

: Our data indicate that AF independently and significantly affects the PVF and leads to characteristic flow patterns different from sinus rhythm. The presence of AF reduces SFF in addition to the absence of atrial RF. These changes in the flow patterns should be taken into account while interpreting the implications of PVF in the presence of AF.

An autologous oral DNA vaccine protects against murine melanoma

We demonstrated that peripheral T cell tolerance toward murine melanoma self-antigens gp100 and TRP-2 can be broken by an autologous oral DNA vaccine containing the murine ubiquitin gene fused to minigenes encoding peptide epitopes gp100(25-33) and TRP-2(181-188). These epitopes contain dominant anchor residues for MHC class I antigen alleles H-2D(b) and H-2K(b), respectively. The DNA vaccine was delivered by oral gavage by using an attenuated strain of Salmonella typhimurium as carrier. Tumor-protective immunity was mediated by MHC class I antigen-restricted CD8(+) T cells that secreted T(H)1 cytokine IFN-gamma and induced tumor rejection and growth suppression after a lethal challenge with B16G3. 26 murine melanoma cells. Importantly, the protective immunity induced by this autologous DNA vaccine against murine melanoma cells was at least equal to that achieved through xenoimmunization with the human gp100(25-33) peptide, which differs in its three NH(2)-terminal amino acid residues from its murine counterpart and was previously reported to be clearly superior to an autologous vaccine in inducing protective immunity. The presence of ubiquitin upstream of the minigene proved to be essential for achieving this tumor-protective immunity, suggesting that effective antigen processing and presentation may make it possible to break peripheral T cell tolerance to a self-antigen. This vaccine design might prove useful for future rational designs of other recombinant DNA vaccines targeting tissue differentiation antigens expressed by tumors.

Association of follow-up change of left atrial appendage blood flow velocity with spontaneous echo contrast in nonrheumatic atrial fibrillation

STUDY OBJECTIVES

To evaluate the time-related change of left atrial (LA) appendage flow velocity in chronic atrial fibrillation (AF) by follow-up transesophageal echocardiography (TEE) and to investigate its association with the occurrence of LA spontaneous echo contrast.

DESIGN

Prospective follow-up study.

SETTING

University-based, tertiary referral medical center.

PATIENTS

Forty-seven patients with chronic nonrheumatic AF.

INTERVENTIONS

All studied patients underwent both a baseline and follow-up TEE during a mean period of 13 +/- 7 months.

MEASUREMENTS AND RESULTS

Baseline TEE revealed that LA spontaneous echo contrast was present in 28 patients (group 1) and was absent in 19 patients (group 2). The LA appendage flow velocity profiles at baseline were significantly lower in group 1 than in group 2; on follow-up, the appendage flow velocities decreased significantly in group 2, but were not significantly changed in group 1. Follow-up TEE revealed that spontaneous echo contrast was persistent in all group 1 patients. In group 2, LA spontaneous echo contrast was newly observed in 9 patients (group 2A) but was persistently absent in 10 patients (group 2B). In group 2A, all of the LA appendage flow velocity profiles decreased significantly at the follow-up study. In group 2B, however, only LA appendage inflow velocity integral showed significant decrease on follow-up; there were no significant changes in LA appendage outflow velocity indexes and peak inflow velocity.

CONCLUSIONS

LA appendage flow velocity may decrease with time in some patients with AF, and this change is associated with a new occurrence of LA spontaneous echo contrast. For patients without LA spontaneous echo contrast, serial follow-up of the LA appendage flow velocity profiles may be useful for predicting future development of spontaneous echo contrast. Once LA spontaneous echo contrast occurs in AF patients, it tends to persist with time and the LA appendage is usually under a persistently low flow state.

G-33A mutation in the promoter region of thrombomodulin gene and its association with coronary artery disease and plasma soluble thrombomodulin levels

Thrombomodulin is an endothelial glycoprotein that decreases thrombin activity and activates protein C. A recent study has shown that G-33A promoter mutation of the thrombomodulin gene occurs particularly in Asians. In this study, we analyzed the distribution of G-33A mutation in the promoter region of the thrombomodulin gene in the Chinese population and determined whether the mutation might be a risk for coronary artery disease (CAD). In addition, the influence of this mutation on plasma soluble thrombomodulin levels in patients with CAD was also examined. We studied 320 consecutive patients (mean age 63 years; 73% men) with CAD and 200 age- and sex-matched control subjects. Screening for thrombomodulin G-33A promoter mutation was conducted using polymerase chain reaction, single-strand conformation polymorphism, and direct deoxyribonucleic acid sequencing. The frequency of the G-33A mutation (GA+AA genotypes) was significantly higher in the CAD group (23.8% vs 15.5%, odds ratio [OR] 1.70, p = 0.031). Multiple logistic regression analysis showed that the mutation was an independent risk factor (OR 1.81, p = 0.016) for CAD, as was hypertension (OR 1.44, p = 0.040), diabetes mellitus (OR 2.50, p <0.001), and smoking (OR 2.15, p <0.001). In CAD patients with GG genotype, the soluble thrombomodulin level increased with the extent of CAD (36 +/- 15 vs 47 +/- 18 vs 55 +/- 36 ng/ml in 1-, 2-, or 3-vessel CAD, p <0.001). However, in CAD patients with G-33A mutation, there was no difference between the levels of soluble thrombomodulin (39 +/- 17 vs 37 +/- 15 vs 42 +/- 18 ng/ml, p = NS) in 1-, 2-, or 3-vessel CAD. Our observations suggest that there is a significant association of the G-33A mutation in thrombomodulin gene with CAD, and this mutation may influence the soluble thrombomodulin levels in patients with CAD.

Correlation of homocytsteine levels with the extent of coronary atherosclerosis in patients with low cardiovascular risk profiles

Elevation of homocysteine is now known as an independent risk factor for vascular diseases. However, influences of homocysteine to the extent of coronary atherosclerosis in patients with different coronary risk profiles have not been studied. In this study, we used angiographic "diffuse score" and "clinical vessel score" to evaluate the extent of coronary atherosclerosis, and examined the correlation between levels of serum total homocysteine and angiographic scores among patients with high- and low-risk profiles. Seventy consecutive patients (58 men and 12 women, mean age 50 years) undergoing selective coronary angiography for the first time were recruited for this study. Patients were divided into high-risk (risk factor > or =3, n = 35) and low-risk (risk factor <3, n = 35) groups. Linear regression analysis revealed that levels of serum homocysteine were only significantly correlated with diffuse (r = 0.217, p = 0.007) and clinical vessel (r = 0.078, p = 0.037) scores in low-risk patients. These correlations could not be observed in diffuse (r = 0.070, p = 0.319) and clinical vessel (r = -0.001, p = 0.970) scores in the high-risk group. In conclusion, levels of homocysteine correlated with the extent of coronary atherosclerosis only among patients with low cardiovascular risk profiles.

MEKK3 directly regulates MEK5 activity as part of the big mitogen-activated protein kinase 1 (BMK1) signaling pathway

Big mitogen-activated protein (MAP) kinase (BMK1), also known as ERK5, is a member of the MAP kinase family whose cellular activity is elevated in response to growth factors, oxidative stress, and hyperosmolar conditions. Previous studies have identified MEK5 as a cellular kinase directly regulating BMK1 activity; however, signaling molecules that directly regulate MEK5 activity have not yet been defined. Through utilization of a yeast two-hybrid screen, we have identified MEKK3 as a molecule that physically interacts with MEK5. This interaction appears to take place in mammalian cells as evidenced by the fact that cellular MEK5 and MEKK3 co-immunoprecipitate. In addition, we show that a dominant active form of MEKK3 stimulates BMK1 activity through MEK5. Moreover, we demonstrate that MEKK3 activity is required for growth factor mediated cellular activation of endogenous BMK1. Taken together, these results identify MEKK3 as a kinase that regulates the activity of MEK5 and BMK1 during growth factor-induced cellular stimulation.

Identification of ligand effector binding sites in transmembrane regions of the human G protein-coupled C3a receptor

The human C3a anaphylatoxin receptor (C3aR) is a G protein-coupled receptor (GPCR) composed of seven transmembrane alpha-helices connected by hydrophilic loops. Previous studies of chimeric C3aR/C5aR and loop deletions in C3aR demonstrated that the large extracellular loop2 plays an important role in noneffector ligand binding; however, the effector binding site for C3a has not been identified. In this study, selected charged residues in the transmembrane regions of C3aR were replaced by Ala using site-directed mutagenesis, and mutant receptors were stably expressed in the RBL-2H3 cell line. Ligand binding studies demonstrated that R161A (helix IV), R340A (helix V), and D417A (helix VII) showed no binding activity, although full expression of these receptors was established by flow cytometric analysis. C3a induced very weak intracellular calcium flux in cells expressing these three mutant receptors. H81A (helix II) and K96A (helix III) showed decreased ligand binding activity. The calcium flux induced by C3a in H81A and K96A cells was also consistently reduced. These findings suggest that the charged transmembrane residues Arg161, Arg340, and Asp417 in C3aR are essential for ligand effector binding and/or signal coupling, and that residues His81 and Lys96 may contribute less directly to the overall free energy of ligand binding. These transmembrane residues in C3aR identify specific molecular contacts for ligand interactions that account for C3a-induced receptor activation.

Prognostic determinants of infective endocarditis in the 1990s

The clinical profiles of infective endocarditis (IE) might have changed in recent years, owing to the advent of transesophageal echocardiography, the introduction of new diagnostic criteria, and the increased frequency of intravenous drug abuse. In this retrospective study, we sought to identify factors affecting the in-hospital outcome of IE patients in a single tertiary referral center in the 1990s (1990-1997). Eighty-eight episodes of IE in 80 consecutive patients admitted from January 1990 through June 1997 were evaluated. Clinical variables that were significantly associated with in-hospital mortality in univariate analyses were entered into a multiple logistic regression model. A total of 22 patients (25%) died. Fatal episodes were significantly more likely than non-fatal episodes to involve older patients (> or = 50 years), use of coumadin, short interval between symptom onset and hospitalization (< 15 days), noncardiac shock, and complications of the heart, central nervous system, and kidneys. White blood cell counts and C-reactive protein concentrations were also significantly higher in fatal than in non-fatal episodes of IE. Multivariate analysis showed that in-hospital mortality was associated with noncardiac shock, neurological complications, cardiac complications, and older age (> or = 50 years). Compared with previous reports, our findings suggest that the clinical profiles of IE have undergone some changes in the 1990s. The most important prognostic predictors of in-hospital mortality in patients with IE were noncardiac shock and neurologic complications.

Role of the second extracellular loop of human C3a receptor in agonist binding and receptor function

The C3a anaphylatoxin receptor (C3aR) is a G protein-coupled receptor with an unusually large second extracellular loop (e2 loop, approximately 172 amino acids). To determine the function of this unique structure, chimeric and deletion mutants were prepared and analyzed in transfected RBL-2H3 cells. Whereas replacement of the C3aR N-terminal segment with that from the human C5a receptor had minimal effect on C3a binding, substitution of the e2 loop with a smaller e2 loop from the C5a receptor (C5aR) abolished binding of 125I-C3a and C3a-stimulated calcium mobilization. However, as much as 65% of the e2 loop sequence (amino acids 198-308) may be removed without affecting C3a binding or calcium responses. The e2 loop sequences adjacent to the transmembrane domains contain multiple aspartate residues and are found to play an important role in C3a binding based on deletion mutagenesis. Replacement of five aspartate residues in the e2 loop with lysyl residues significantly compromised both the binding and functional capabilities of the C3a receptor mediated by intact C3a or by two C3a analog peptides. These data suggest a two-site C3a-C3aR interaction model similar to that established for C5a/C5aR. The anionic residues near the N and C termini of the C3aR e2 loop constitute a non-effector secondary interaction site with cationic residues in the C-terminal helical region of C3a, whereas the C3a C-terminal sequence LGLAR engages the primary effector site in C3aR.

Decreased left atrial appendage function is an important predictor of elevated left ventricular filling pressure in patients with congestive heart failure

OBJECTIVE

The aim of this study was to investigate whether left atrial (LA) appendage function, as indicated by LA appendage blood flow velocities and its ejection fraction, could identify elevated left ventricular filling pressure in patients with chronic congestive heart failure.

METHODS

Using transesophageal echocardiography, adequate pulsed Doppler LA appendage active emptying and filling velocities could be recorded in 25 consecutive patients (16 men and 9 women, aged 57+/-10 years) with chronic congestive heart failure (symptom duration > or =1 year). LA appendage ejection fraction calculated as (LA appendage maximal area)-(LA appendage minimal area)/(LA appendage maximal area) x 100 was also determined in these patients. Left ventricular end-diastolic pressure was recorded during cardiac catheterization performed within 24 h of echocardiographic study.

RESULTS

Left ventricular end-diastolic pressure was 2 to 47 mm Hg. There were close negative correlations of LA appendage emptying velocity (r=-0.508; P<0.01), filling velocity (r=-0.429; P<0.05) and LA appendage ejection fraction (r=-0.523; P<0.005) with left ventricular end-diastolic pressure. LA appendage active emptying velocity <30 cm/s predicted left ventricular end-diastolic pressure >25 mm Hg with a sensitivity of 72.7%, a specificity of 92.9% and a positive and negative predictive value of 88.9 and 81.3%.

CONCLUSIONS

The findings suggest that measurement of LA appendage blood flow velocities and contractile function by transesophageal echocardiography can be used to predict elevated left ventricular filling pressure in patients with congestive heart failure.

Successful delayed thrombolytic therapy in a patient with massive pulmonary embolism

Pulmonary embolism can be a catastrophic event leading to early death or serious hemodynamic instability. Thrombolytic therapy, in addition to heparin therapy, may improve the clinical condition and reduce the chance of recurrent pulmonary embolism in some cases. However, the acceptable "time window" for thrombolytic therapy is not well documented, though it has been used successfully as late as 14 days after pulmonary embolism. Successful delayed thrombolytic therapy beyond this "time window" in patients with massive pulmonary embolism has not been reported. We report a case of massive pulmonary embolism in which thrombolytic therapy was delayed more than 1 month after symptom onset. A 56-year-old woman was taken to National Cheng Kung University Hospital because of an episode of recurrent syncope, followed by progressive shortness of breath of 1 month's duration. Hypoxemia and hemodynamic instability were noted on admission. Echocardiography and a lung perfusion scan provided strong evidence of pulmonary embolism. Subsequent pulmonary angiography confirmed the diagnosis of multiple pulmonary emboli. The patient received a standard dose of intravenous tissue plasminogen activator 7 days after admission because of persistent symptoms and hypoxemia. Her clinical condition dramatically improved after treatment. Follow-up imaging studies showed resolution of the emboli. She was discharged in good condition. This case suggests that delayed thrombolytic therapy in patients with massive pulmonary embolism can still be beneficial in selected cases, even if given more than 2 weeks after symptom onset.

Amebic liver abscess complicated with cardiac tamponade and mediastinal abscess

Amebic pericarditis is an extremely rare complication of liver abscess and an uncommon etiology of sterile pericardial effusion with cardiac tamponade. The association of mediastinal abscess in this clinical setting has not been reported in the literature. Herein, we describe a case of amebic liver abscess complicated with mediastinal abscess and amebic pericarditis with cardiac tamponade. A 44-year-old man was admitted to our hospital because of shortness of breath for the previous 2 days. Cardiac tamponade was diagnosed and emergency pericardiectomy was performed. Chocolate-like pus was found in the pericardial sac and mediastinal space during surgery. Abdominal computed tomography revealed an ill-defined hypodense lesion over the left lobe of the liver, suggesting a liver abscess. Amebic liver abscess and pericarditis were diagnosed on the basis of a high serum titer of amebic antibodies on hemagglutination test. The patient was treated with metronidazole for 2 weeks and discharged in good condition. This case should alert clinicians to the possibility of amebic pericarditis in patients with cardiac tamponade associated with chocolate-like sterile pus in the pericardium and mediastinum. To establish the diagnosis of amebic pericarditis, one should investigate the presence of a liver abscess, a high serum titer of amebic hemagglutination antibodies, and the presence of Entamoeba histolytica trophozoites in the pericardium or pericardial aspirate.

Cloning, nucleotide sequence and characterization of a full-length cDNA encoding the myosin heavy chain from adult chicken pectoralis major muscle

Four cDNA clones, encoding the chicken adult sarcomeric MyHC, have been isolated from a pectoralis major muscle cDNA library using gene-specific DNA probes. These clones were sequenced and then subcloned into a full-length, 6-kb, chicken adult sarcomeric MyHC cDNA. The entire cDNA consists of 5873 nucleotides with 19 bp 5'-untranslated region and 34 bp 3'-untranslated region. The complete cDNA encodes a 1939-aa polypeptide whose molecular weight is 223 kDa. The calculated isoelectric point of this protein is approximately 5.7. Analysis of the deduced amino acid sequence and comparison with a previously published amino-acid sequence of the same MyHC isoform reveals that six amino acid residues are different. Hydrophilicity analysis of this adult MyHC amino-acid sequence shows a similar pattern as the embryonic MyHC. A recombinant baculovirus, carrying this full-length adult MyHC cDNA, has also been generated and expressed in the Sf9 insect cell line. A approximately 220-kDa recombinant MyHC was synthesized and reacted specifically with chicken adult MyHC monoclonal antibodies.

Clinical treatment in colonoscopic perforation: a comparison of surgical and conservative management

BACKGROUND

Successful management of colonoscopic perforation by conservative treatment has been reported, but management remains controversial. Delayed surgery in some situations may lead to an irretrievable result. How to make the best decision? A retrospective study was designed to address this challenge.

METHODS

From the period October 1982 and December 1995, 9214 consecutive colonoscopic examinations at Taichung Veterans General Hospital were reviewed.

RESULTS

Twenty perforations (0.22%) related to the procedure were found. Of those 16 occurred during diagnostic colonoscopies, and four, during therapeutic colonoscopies. Fifteen perforations caused by diagnostic colonoscopies were treated by surgery, one perforation caused by diagnostic colonoscopy and the four by therapeutic colonoscopies were treated by non-surgical methods.

CONCLUSIONS

A standard text on large bowel surgery recommends laparotomy for most cases of colonoscopic perforations. In experience here, however, non-operative management was indicated if the perforation was small with no signs of general peritonitis, and the patient's condition was good. However, if the patients deteriorated with non-operative treatment, immediate laparotomy is indicated.

Optical implementation of a feature-based neural network with application to automatic target recognition

An optical neural network based on the neocognitron paradigm [IEEE Trans. Syst. Man Cybern. SMC-13, 826-834 (1983)] is introduced. A novel aspect of the architectural design is shift-invariant multichannel Fourier optical correlation within each processing layer. Multilayer processing is achieved by feeding back the output of the feature correlator iteratively to the input spatial light modulator and by updating the Fourier filters. By training the neural net with characteristic features extracted from the target images, successful pattern recognition with intraclass fault tolerance and interclass discrimination is achieved. A detailed system description is provided. Experimental demonstrations of a two-layer neural network for space-object discrimination is also presented.

Liquid crystal television spatial light modulators

The spatial light modulation characteristics and capabilities of the liquid crystal television (LCTV) spatial light modulators (SLMs) are discussed. A comparison of Radio Shack, Epson, and Citizen LCTV SLMs is made.

Real time optical edge enhancement using a Hughes liquid crystal light valve

A new real time edge enhancement effect using a Hughes CdS liquid crystal light valve and ts use in optical correlation are reported.

Real-time optical holographic tracking of multiple objects

A coherent optical correlation technique for real-time simultaneous tracking of several different objects making independent movements is described, and experimental results are presented. An evaluation of this system compared with digital computing systems is made. The real-time processing capability is obtained through the use of a liquid crystal television spatial light modulator and a dichromated gelatin multifocus hololens. A coded reference beam is utilized in the separation of the output correlation plane associated with each input target so that independent tracking can be achieved.

Spatial light modulation by beam coupling in GaAs crystals

We present the first reported demonstration of spatial light modulation in GaAs using the photorefractive effect. The demonstration was done with a special configuration in which polarization rotation created by beam coupling was utilized.

Grating generation with an encoded extended incoherent source

A new technique for constructing a low-noise linear-diffraction grating by an optical processing technique with an encoded extended incoherent source is presented. Experimental results obtained with this technique show a substantial improvement in the reduction of coherent artifact noise over that obtained by means of traditional holographic techniques.

Smeared-photographic-image deblurring utilizing white-light-processing technique

A white-light-processing technique for smeared-photographic-image restoration is described. A simple technique of synthesizing a complex deblurring spatial filter is also given. Experimental demonstrations of smeared-image deblurring with a white-light-processing technique are provided. Compared with the coherent-processing technique, the white-light technique offers artifact-noise suppression, and the processing system is simple, versatile, and economicaL. We note that the white-light-processing technique is suitable for smeared-color-image restoration.

Real-time white light spatial frequency and density pseudocolor encoder

A real-time white light pseudocolor encoding technique for spatial frequency and density encodings is presented. In spatial frequency color coding, the encoding is accomplished by spatial filtering of the color signal spectra, while in density pseudocoloring, the encoding consists of contrast reversal of a color object image. The technique is simple, versatile, and economical to operate, which may offer some practical applications. Because the encoding colors are primarily derived from a white light source, the annoying coherent artifact noise can be substantially reduced. Since the encoding is obtained with a broad spatial band of the signal spectra, this technique offers no apparent resolution loss. We stress that this real-time white light pseudocolor encoding technique may offer several major advantages that previous techniques have offered. Experimental demonstrations of this pseudocolor encoding technique are also provided.

Optimum correlation detection by prewhitening

An optimization technique for the optical correlation detection process is proposed. The noise correlation output is suppressed by prewhitening its spectrum. Since the optimization operates on the noise instead of the signal spectrum, the system tolerance for size and orientation variation is not severely affected. Experimental illustrations are also presented.

White-light pseudocolor density encoding through contrast reversal

A simple technique of pseudocolor density encoding of photographic image by white-light processing is described. Spatial encodings are made through positive and negative photographic-image transparencies, and the pseudocoloring is obtained by color filtering of the smeared Fourier spectra. The technique is simple, versatile, and economical to operate. Since coherent sources are not used, annoying coherent artifact noise can be eliminated. Spatial color encoding uses the entire Fourier spectrum; therefore, this technique offers no apparent resolution loss. Simple experimental demonstrations of this technique are provided.