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Summary: Exploring early embryonic gene expression is challenging due to the rate of development and the limited material available. Here, we present a protocol for ordering Drosophila embryos along a developmental pseudo-time trajectory and determining the sex of the embryos using RNA-seq data. We describe steps for sample collection, RNA isolation, RNA-seq, and RNA-seq data processing. We then detail the establishment of a continuous transcriptome dataset for assessing gene expression throughout early development and in a sex-specific manner.For complete details on the use and execution of this protocol, please refer to Pérez-Mojica et al.1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Summary: Obese individuals experience low grade inflammation initiated within their adipose tissue. However, the early events that lead to the release of these inflammatory factors from adipose tissue are poorly characterized. To separate glucose effects from lipid effects on adipose tissue, we used an adipose-specific TXNIP knockout model where excess basal glucose influx into adipocytes led to modest increase in adiposity without using high fat diet. We found an uncoupling of two events that are generally presumed to be coregulated: (1) an increase of adipose tissue macrophage (ATM) number; and (2) pro-inflammatory activation of ATMs. These two events are associated with different triggering signals: elevated free fatty acids output and extracellular matrix remodeling with increased ATM number, whereas decreased adiponectin level with activated ATM. This separation reflects non-overlapping pathways regulated by glucose and lipids in adipocytes, and neither group alone is sufficient to elicit the full inflammatory response in adipose tissue.

Summary: While TXNIP (thioredoxin interacting protein) in the plasma membrane and vesicular location is known to negatively regulate cellular glucose uptake by facilitating glucose transporter endocytosis, the function of TXNIP in the nucleus is far less understood. Herein, we sought to determine the function of nuclear TXNIP in vivo, using a new HA-tagged TXNIP knock-in mouse model. We observed that TXNIP can be found in the nucleus of a variety of cells from different tissues including hepatocytes (liver), enterocytes (small intestine), exocrine cells (pancreas), and brown adipocytes (BAT). Further investigations into the role of nuclear TXNIP in BAT revealed that cold stress rapidly and transiently activated HSF1 (heat shock factor 1). HSF1 interaction with TXNIP during its activation is required for optimal HSF1 directed cold shock response in BAT.

Summary: Antibody-secreting cells (ASCs) are key contributors to humoral immunity through immunoglobulin production and the potential to be long-lived. ASC persistence has been recognized in the autoimmune thymus (THY); however, only recently has this population been appreciated in healthy THY tissue. We showed that the young female THY was skewed toward higher production of ASCs relative to males. However, these differences disappeared with age. In both sexes, THY ASCs included Ki-67+ plasmablasts which required CD154(CD40L) signals for their propagation. Single cell RNA-sequencing revealed that THY ASCs were enriched for an interferon responsive transcriptional signature relative to those from bone marrow and spleen. Flow cytometry confirmed that THY ASCs had increased levels of Toll-like receptor 7 as well as CD69 and major histocompatibility complex class II. Overall, we identified fundamental aspects of THY ASC biology which may be leveraged for future in depth studies of this population in both health and disease.

Summary: Brown adipose tissue (BAT) has the ability to burn calories as heat. Utilizing BAT thermogenesis is thus an attractive way to combat obesity. However, the transcriptional network resulting in the lipid synthesis to oxidation shift during thermogenesis is not completely understood. Here, we report the regulation of two master regulators of adipogenesis, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), during acute cold stress in BAT. We found PPARγ dissociates from DNA in a fifth of its binding sites and these include Cebpa enhancers, leading to decreased C/EBPα expression. This dissociation requires PPARγ binding to activating ligands and is thus modulated by diet. Meanwhile, PPARα also detaches from DNA, and co-activator PGC1α associates with ERRα as part of a transcriptional network regulating lipid metabolism. Subsequent global replacement of C/EBPα by C/EBPβ and its associated transcriptional machinery is required for upregulation of structural lipid synthesis despite general upregulation of fatty acid oxidation.

Al–Si–Zn–Mg–Fe alloy in as-cast and artificially aged (T6) conditions was friction stir-welded with a traveling speed of 200 mm/min and a rotation speed of 800 rpm. Their microstructure, mechanical and corrosion properties were investigated. α-Al, Si, Mg2Si, MgZn2 and Fe-rich phase were detected in the as-cast and pre-aged Al–Si–Zn–Mg–Fe before and after FSW. The secondary phases in pre-aged Al–Si–Zn–Mg–Fe after FSW are slightly more than those in the as-cast Al–Si–Zn–Mg–Fe after FSW. For the pre-aged Al–Si–Zn–Mg–Fe after FSW, the grains are refined and the dislocation density decreases. Hardness of the pre-aged Al–Si–Zn–Mg–Fe is higher than that of the as-cast one, whereas the hardness of weld nugget zones (NZs) of the both FSWed Al–Si–Zn–Mg–Fe joints is lower than their base materials, and the strength coefficients of both FSWed joints of the as-cast and pre-aged Al–Si–Zn–Mg–Fe are 0.82 and 0.9 respectively. The ultimate tensile strength (UTS) and yield strength (YS) of the pre-aged Al–Si–Zn–Mg–Fe after FSW (UTS = 208.86 MPa and YS = 156.72 MPa) is about 35% higher than that of as-cast Al–Si–Zn–Mg–Fe after FSW (UTS = 159.4 MPa and YS = 112.06 MPa) mainly due to the smaller grain size and more precipitates in the former. The corrosion resistance (CR) of the FSWed joint of the pre-aged Al–Si–Zn–Mg–Fe is the highest, owing to the most refined grain size, highest HAGBs, lowest KAM, increase in the close-packed {111} (α-Al) texture, dispersed particles of secondary phases, followed by the pre-aged Al–Si–Zn–Mg–Fe and then the FSWed joint of the as-cast Al–Si–Zn–Mg–Fe, and the as-cast one is the lowest.

Background: COVID-19 outbreaks in residential care homes for the elderly (RCHEs) and for persons with disability (RCHDs) have caused significant morbidity and mortality during 5th epidemic in Hong Kong. This article reviewed COVID-19 outbreaks situation and estimated the effectiveness of receiving at least two-dose of COVID-19 vaccine in preventing severe outcomes. Methods: To estimate attack rates and vaccination coverage, documentation on COVID-19 infection and their vaccination records of residential care homes (RCH) residents reported between December 31, 2021 and May 31, 2022 were reviewed, and infected cases were follow-up for 4 weeks for severe outcomes or death. Correlation between vaccination coverage against attack rate by types of homes was examined. Infected RCH residents with available information were included in the analysis of vaccine effectiveness against severe outcomes and death. Results: COVID-19 vaccination coverage was low in RCHDs (median 0.46, IQR: 0.24–0.76) and very low in RCHEs (median 0.08, IQR: 0.00–0.19). Higher attack rates were recorded among RCHE residents (median 0.84, IQR: 0.64–0.93) and higher case fatality rate (CFR: 28.1%) than in RCHDs (median 0.58, IQR: 0.31–0.84; CFR: 3.9%). The attack rate decreased when vaccination coverage increased for both RCHEs (ρ = −0.131, p < 0.001) and RCHDs (ρ = −0.333, p < 0.001). Comparing with infected residents who were unvaccinated/vaccinated with one-dose, receiving at least two-dose was estimated to be effective in reducing severe outcomes in 31% and 36% of infected RCHE and RCHD residents respectively; with greater reduction in mortality among RCHD than RCHE residents (54% and 38%, respectively). Vaccine effectiveness of two-dose of BNT162b2 against severe outcomes and death are higher than that of CoronaVac. Conclusions: Increasing COVID-19 vaccination could have significant impact on reducing the risk of COVID-19 outbreaks in RCHs. At least two-dose of COVID-19 vaccine is still effective in reducing severe outcomes and death among infected residents in RCHs during Omicron epidemic.

Unmanned aerial vehicles (UAVs) have gained much attention from academic and industrial areas due to the significant number of potential applications in urban airspace. A traffic management system for these UAVs is needed to manage this future traffic. Tactical conflict resolution for unmanned aerial systems (UASs) is an essential piece of the puzzle for the future UAS Traffic Management (UTM), especially in very low-level (VLL) urban airspace. Unlike conflict resolution in higher altitude airspace, the dense high-rise buildings are an essential source of potential conflict to be considered in VLL urban airspace. In this paper, we propose an attention-based deep reinforcement learning approach to solve the tactical conflict resolution problem. Specifically, we formulate this task as a sequential decision-making problem using Markov Decision Process (MDP). The double deep Q network (DDQN) framework is used as a learning framework for the host drone to learn to output conflict-free maneuvers at each time step. We use the attention mechanism to model the individual neighbor's effect on the host drone, endowing the learned conflict resolution policy to be adapted to an arbitrary number of neighboring drones. Lastly, we build a simulation environment with various scenarios covering different types of encounters to evaluate the proposed approach. The simulation results demonstrate that our proposed algorithm provides a reliable solution to minimize secondary conflict counts compared to learning and non-learning-based approaches under different traffic density scenarios.

Denervation of muscle usually leads to muscle atrophy with fatty replacement but, uncommonly, also results in muscle hypertrophy or pseudohypertrophy with fatty replacement. We report the ultrasonographic and magnetic resonance imaging (MRI) findings of a patient with diffuse fatty infiltration of calf muscles as a result of denervation pseudohypertrophy. The elevated fasting glucose, neurogenic electromyographic changes, and muscle atrophy with adipose tissue infiltration are consistent with diabetic neuropathy as the cause of denervation pseudohypertrophy. Lumbosacral radiculopathy and plexopathy were excluded by MRI. The imaging features reported in the literature are reviewed. The important differential diagnosis of infiltrating lipoma and denervation hypertrophy, as well as other causes of monomelic hypertrophy or swelling, is discussed. This case report demonstrates the importance of MRI, with clinical, biochemical, electrophysiological, and histologic correlation in the diagnosis of denervation pseudohypertrophy. Correct diagnosis of denervation pseudohypertrophy has an important role in guiding further investigations and treatment of the disease and the underlying cause.

Background: Children with severe motor and intellectual disabilities (SMID) are at a high risk of malnutrition and often require tube feeding to maintain their nutritional status. However, determining their energy requirements is difficult since inadequate dietary intake, severe neurological impairment, respiratory assistance, and cognitive impairment are all factors that affect malnutrition in SMID., Aim: This study investigated the factors affecting malnutrition and identified problems affecting the nutritional status of children with SMID., Methods: Forty-two children with SMID with oral motor dysfunction who were receiving home medical care at one of four hospitals were enrolled. Their nutritional status was assessed using a 3-day dietary record, anthropometric measurements, and laboratory tests. The clinical findings associated with malnutrition were compared, and a body mass index (BMI) z-score less than -2SD was defined as malnutrition. The relationship between BMI z-score and other potential predictors was also investigated., Results: Thirty-three (79%) children received tube feeding, and 20 (48%) experienced malnutrition. The median age of the malnourished children was older than that of non-malnourished children. Respiratory assistance was significantly correlated with higher BMI z-score, independent of other potential confounders such as nutrition method, muscle tonus, and energy intake. Cholesterol levels were significantly higher in children receiving a standard infant formula beyond 3 years of age than in those who switched to enteral formula before 3 years of age., Conclusions: Malnutrition in children with SMID was mainly associated with age or respiratory condition. Energy requirements should be regularly re-evaluated with considering these factors., (Copyright © 2020 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Background: Early cardiac surgery may have a trade-off between stabilized hemodynamics with controlled infection and a risk of peri-operative death in patients with infective endocarditis (IE) complicated with cardio-embolic strokes., Methods: We retrospectively studied clinical characteristics and outcomes in 68 consecutive patients with IE (mean age, 58±3years, 62% male) who admitted in our institute during June 2013 and August 2015., Results: Cardio-embolic strokes were noted in 37% of patients (n=25) with IE and overall in-hospital mortality was 4 times higher in IE with cardio-embolic strokes than IE with an absence of strokes (n=43) (20% vs. 4.7%, p=0.045). Bacteremia of Staphylococcus aureus (p=0.021) and a complication of cardio-embolic strokes (p=0.031) were independently associated with in-hospital death in those with IE. However, in-hospital mortality was quite low in 19 with early cardiac surgery compared with 6 with conventional treatment in those with cardio-embolic strokes (11% vs. 50%, p=0.035). Multivariate logistic analysis demonstrated that lack of early cardiac surgery (p=0.014), a complication of cerebral hemorrhage (p=0.002), and a presence of refractory heart failure (p=0.047) were independently associated with in-hospital death in those with IE complicated with cardio-embolic strokes., Conclusion: Early cardiac surgery may provide clinical advantages overcoming peri-operative risks in those with IE complicated with cardio-embolic strokes., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

We report the successful repair of a rare case of regional thinning of the left ventricle after mitral valve replacement. An 80-year-old woman underwent prosthetic mitral valve replacement for mitral valve stenosis. Her postoperative course was uneventful; however, regional thinning of the left ventricular wall was detected on transthoracic echocardiography on postoperative day 7. We repaired the thinned area with a patch by using the felt sandwich technique. Postoperative echocardiography and computed tomography showed a successfully repaired left ventricular wall., (Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Carnitine plays a pivotal role in a variety of cellular functions. Carnitine deficiency often occurs in severely disabled patients, especially under valproic acid administration. However, the possible causative factors underlying carnitine deficiency have not been fully identified. The present study aimed at clarifying the association of various anthropometric and biochemical variables, including dietary intake of carnitine, with carnitine levels in severely disabled patients., Methods: Twenty-six severely disabled patients (mean age: 14.1 years; s.d. 7.8) were enrolled. Plasma carnitine levels were evaluated by an enzyme cycling assay. Estimation of the dietary intake of carnitine was made based on dietary records over a 3-day period., Results: Plasma total and free carnitine levels in patients were significantly lower than those in controls obtained from the previous report. However, the ratios of free carnitine to total carnitine did not change significantly. Free carnitine levels were well correlated with a nutritional intake of carnitine. Administration of not only valproic acid but also other anti-epileptic drugs was found to cause a significant decrease of free carnitine levels after adjusting the nutritional intake of carnitine. Among various anthropometric or biochemical variables, albumin and uric acid showed a significant correlation with free carnitine levels., Conclusions: Physicians should be aware of the fact that severely disabled patients are at risk for carnitine deficiency even in the absence of valproic acid administration, and pay more attention to the nutritional intake of carnitine., (Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

The management of congenitally corrected transposition of the great arteries and associated lesions is frequently challenging. Restrictive ventricular septal defect and mild pulmonary stenosis are contraindications to the double switch procedure, including the atrial-Rastelli switch procedure, due to the production of postoperative left ventricular outflow tract obstruction. We describe a case of aortic translocation using the hemi-Mustard procedure after left ventricular training in order to prevent postoperative left ventricular outflow obstruction., (Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Controversy exists concerning the optimal surgical treatment of acute type A aortic dissection to reduce mortality rate and the need for reoperation. The goal of the present study was to evaluate midterm results of repair using a fabric and fibrin glue for acute type A aortic dissection., Methods: From 1994 to 2005, 100 patients with acute type A aortic dissection underwent supracommissural graft replacement using a fabric as "neomedia" and fibrin glue. Mean patient age was 65.7 +/- 11.3 years., Results: Hospital mortality was 9%. All 91 survivors underwent follow-up evaluation for a mean period of 47.7 months. Aortic regurgitation was restored to non or mild in 46 survivors who had preoperative aortic regurgitation in the immediate period, and only one patient developed moderate aortic regurgitation in the midterm period. Survival at 1, 5, and 10 years including hospital mortality was 89.0 +/- 3.1%, 75.2 +/- 5.1%, and 59.2 +/- 10.9%, respectively. Reoperation for aortic lesion was performed without mortality in three patients (residual dissection, n = 1; sinus of Valsalva dilatation, n = 1; acute redissection, n = 1). During two late reoperations, the fabric was observed to be firmly adherent to the dissected wall and maintained the shape of the aorta. Freedom from aortic reoperation was 98 +/- 2% and 98 +/- 2%, at 5 and 10 years, respectively., Conclusions: Supracommissural aortic replacement using a fabric neomedia and fibrin glue resulted in low early and late mortality as well as a low reoperation rate.

Background: Deep hypothermic circulatory arrest (DHCA) causes myocyte injury as a consequence of ischemia and reperfusion. Previous studies have shown that hypoxia or hypoxia-mimetic agents (cobalt chloride [CoCl2] or deferoxamine [DFX]) limit myocyte necrosis by upregulating the transcription factor hypoxia-inducible factor. However, it remains unknown whether these agents attenuate myocardial apoptosis after DHCA. This study tested the hypotheses (1) that hypoxia, DFX, or CoCl2 preconditioning attenuates myocardial apoptosis during DHCA; and (2) that the protective mechanism involves the altered expression of apoptosis regulatory proteins pAkt (antiapoptotic), Bcl-2 (antiapoptotic), and Bax (proapoptotic)., Methods: Anesthetized neonatal piglets were randomly assigned to four groups (n = 6 in a group): control (NaCl injection); hypoxia (pO2 of 30 to 40 mm Hg for 3 hours); DFX injection; or CoCl2 injection. Twenty-four hours later, the animals underwent cardiopulmonary bypass (CPB) and 110 minutes of DHCA. One week after CPB, percentage of apoptotic myocytes (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling [TUNEL] assay) and expression of the pAKT, Bcl-2, and Bax were assessed by Western blot., Results: Although preconditioning with hypoxia and DFX failed to show a protective benefit, CoCl2 pretreatment significantly attenuated myocardial apoptosis (9.3% +/- 4.1%) versus controls (33.8% +/- 9.7%, p = 0.042). That was associated with increased myocardial pAkt expression (0.19 +/- 0.006 in CoCl2 versus 0.12 +/- 0.008 in control, p < 0.001). The expression of Bcl-2 was also significantly higher in the CoCl2 group (0.15 +/- 0.02) versus control (0.11 +/- 0.01, p = 0.007), whereas Bax expression was lower (0.34 +/- 0.04 versus 0.54 +/- 0.03 for control, p < 0.001)., Conclusions: Preconditioning with CoCl2 before prolonged DHCA in neonatal piglets attenuates myocardial apoptosis by mechanisms involving phosphorylation of Akt, upregulation of the antiapoptotic protein Bcl-2, and decreased expression of the proapoptotic protein Bax.

Background: Ischemic preconditioning (IPC) has been used in off-pump coronary artery bypass surgery (OPCAB) to reduce potential injury secondary to ligation of the target vessel. Previous studies have shown that a brief period of repetitive coronary occlusion applied at the onset of reperfusion, postconditioning (postcon), attenuates myocardial injury. This study tested the hypothesis that coincident application of IPC and postcon would provide more cardioprotection than either intervention alone by inhibiting oxidant-mediated injury after ischemia and reperfusion., Methods: Four groups of open-chest canines endured 60 minutes coronary occlusion followed by 3 hours reperfusion: control (n = 10), no intervention; IPC (n = 9), 5 minutes left anterior descending coronary artery occlusion preceded 10 minutes of reperfusion before prolonged occlusion; postcon (n = 10), 3 cycles of 30 seconds reperfusion-30 seconds reocclusion were imposed immediately upon reperfusion; IPC+postcon (n = 8), IPC and postcon algorithms were combined., Results: Collateral blood flow during ischemia was similar in all groups. Compared to control (24% +/- 2%), infarct size was comparably reduced in IPC (13% +/- 2%* [* denotes p less than 0.05 compared with control]), and postcon (10% +/- 1%*), consistent with a reduction in plasma creative kinase activity in these groups; infarct size was not further reduced by IPC+postcon (12% +/- 3%*). Tissue water content in ischemic myocardium was comparably reduced in IPC, postcon, and IPC+postcon compared to control. Superoxide anion generation detected by dihydroethidium staining in area at risk myocardium was comparably reduced in all intervention groups relative to control. Plasma malondialdehyde (microM), a lipid peroxidation byproduct of oxidant injury, was less at 1 hour of reperfusion in IPC (2.2 +/- 0.2*), postcon (2.1 +/- 0.2*), and IPC+postcon (2.5 +/- 0.2*) relative to control (3.3 +/- 0.2). Ventricular fibrillation occurred less often in all intervention groups., Conclusions: No additive cardioprotective effects by IPC and postcon were observed in a canine model of regional ischemia and reperfusion. The potent attenuation of myocardial injury by postcon may suggest a clinically applicable strategy during some surgical revascularization procedures (ie, OPCAB).

Purpose: We investigated in detail the state of internal iliac artery (IIA) aneurysms over the midterm after the exclusion procedure., Methods: From January 1990 to December 1998, 29 patients underwent the exclusion procedure for IIA aneurysms. The medical records of 27 survivors were retrospectively reviewed, and 30 excluded aneurysms of these patients were followed up with computed tomography scanning over the midterm., Results: In the immediate postoperative period, 26 aneurysms were completely thrombosed, and four were incompletely thrombosed. In the midterm, 24 aneurysms were completely thrombosed (complete group), and six were incompletely thrombosed (incomplete group). No aneurysms expanded or ruptured during the follow-up period from 6 to 98 months (mean, 26 months). The size of the excluded aneurysm decreased in 22 of 24 aneurysms in the complete group, but no change in size was noted in the six aneurysms in the incomplete group. The preoperative size of the IIA aneurysm in the incomplete group was significantly larger than that in the complete group (P =.0047). The size of two aneurysms in the incomplete group was smaller than 3.0 cm. The aneurysms in the incomplete group extended significantly deep into the pelvis as compared with those in the complete group (P =.0008)., Conclusions: The exclusion of IIA aneurysm did not reliably result in thrombosis of the aneurysm. For IIA aneurysms extending deeply into the pelvis, even if the size of the aneurysm is smaller than 3.0 cm, the exclusion procedure should not be performed.

Objective: It is well known that electroencephalograms (EEGs) show electrical silence in deep anesthesia as well as brain death. This is the first report on intracranial EEG changes in deep anesthesia., Methods: We developed a new direct brain monitoring system capable of recording intracranial EEGs. This study included 13 patients with head trauma or cerebrovascular accident under deep anesthesia., Results: The intracranial EEGs showed different patterns of wave activity in depth compared with the cortical surface. In 3 of the cases, the scalp EEG showed a flat tracing at 2.0-2.5% of isoflurane. In two of the cases, the intracranial EEGs showed electrical silence when the scalp EEG was flat. Decreasing the concentration of isoflurane to 1.5%, the intracranial EEG showed single paroxysmal appearance of 'revival' theta waves on the electrocorticogram (ECoG) or electroventriculogram (EVG). The intracranial 'revival' wave was followed by high-voltage burst-waves. In another case, at 2.0-2.5% of isoflurane, the amplitude of the waves was greatest on the EVG., Conclusion: There is wave activity difference in the brain depth, which the scalp EEG is unable to show. Intracranial EEGs are able to show the first signs of revival after a nearly flat tracing in deep anesthesia.

Purpose: This study was performed to evaluate the effects of a residual dissection on coagulation, fibrinolysis, and platelet function after surgical treatment of acute type A aortic dissection., Methods: Between 1987 and 1995, 48 consecutive patients underwent emergency surgery for acute type A aortic dissection. Thirty-five of 41 survivors were followed-up for periods ranging from 6 to 112 months (median, 30.3 months). These survivors were classified into three groups by computed tomographic scanning and angiography. Fifteen patients had no residual dissection (group I). Of the 20 patients who had residual dissection, nine had an enlarged aorta greater than 45 mm in maximal diameter (group II), and 11 had an aorta less than 45 mm in maximal diameter (group III). For all patients, blood samples were collected for coagulation, fibrinolysis, and platelet function studies on the same day that the computed tomographic scanning had been performed., Results: beta-thromboglobulin, thrombin-antithrombin III complex, D-dimer, and alpha 2 plasmin inhibitor-plasmin complex concentrations were significantly higher in group II than in the other two groups. Strong correlations between the maximal diameter of the dissected aorta and beta-thromboglobulin, thrombin-antithrombin III complex, D-dimer, and plasmin inhibitor-plasmin complex concentrations were evident. In contrast, correlations between the length of the dissected aorta and coagulation/fibrinolysis measurements were weak., Conclusions: Our findings suggest that the coagulopathy worsened in proportion to the degree of dilatation of the dissected aorta.

To assess tricuspid regurgitation (TR) in patients with permanent transvenous right ventricular (RV) pacing, we performed phonocardiographic, contrast and pulsed Doppler echocardiographic studies in 18 patients with transvenous leads for RV pacing. In addition, a pathological study was performed on 26 autopsy cases with transvenous leads for RV pacing. None of the patients had right-sided heart failure. The previous phonocardiograms revealed regurgitant murmurs of TR in one clinical case and five autopsy cases. In the clinical study, definite TR was diagnosed both by contrast and pulsed Doppler echocardiography in five cases (28%). Probable TR was diagnosed only by one technique in three cases (17%), and the absence of TR was confirmed by both techniques in 10 cases (55%) (non-TR group). The average right atrial dimension was 59 +/- 5.3 mm in the definite TR group and 39 +/- 2.4 mm in the non-TR group (p less than 0.01). The average inferior vena cava dimension was 19 +/- 1.7 mm in the definite TR group and 15 +/- 0.8 mm in the non-TR group (p less than 0.05). Right atrial and inferior vena cava dimensions showed a significantly positive correlation (r = 0.58, p less than 0.05). In the pathological study, the presence of TR, which was explained by the position of the pacemaker lead in relation to the valve structure, was confirmed in 11 cases (42%). Valve motion interference was classified as type I (two cases), in which the lead was suppressed and the leaflet immobilized, type II (4 cases), in which chordae tendineae were involved by a pacemaker lead, and type III (five cases), in which both mechanisms contributed to valvular regurgitation. In conclusion, TR may follow transvenous RV pacing in approximately half of the cases with RV pacing. Contrast and pulsed Doppler echocardiography are sensitive noninvasive techniques for detecting this valvular abnormality and they should be used in the follow-up of such pacemaker recipients.