Is preoperative intracranial hemorrhage a surgical contraindication in infective endocarditis with stroke?

Background

The optimal timing for surgery in infective endocarditis (IE) with hemorrhagic stroke and neurologic deficits is difficult to decide because of the risk of exacerbating the stroke and provoking intracranial hemorrhagic conversion after surgery using cardiopulmonary bypass (CPB). This retrospective study aimed to investigate the impact of the presence or absence of preoperative intracranial hemorrhage (ICH) on surgical outcomes in IE with recent stroke.

Methods

The medical records of all patients who underwent open heart surgery for active IE from February 2009 to December 2020 were retrospectively reviewed. Among 164 patients who had surgery for left-sided IE, 71 cases in which the period from stroke onset to surgery was <4 weeks were divided into two groups for analysis.

Results

Group A consisted of 49 patients without preoperative ICH and group B consisted of 22 patients with preoperative ICH. There was no significant difference in underlying conditions between the two groups. The two groups had similar rates of postoperative ICH (10.2%, group A vs. 13.6%, group B, P=0.696). The 30-day mortality rate was 8.2% in group A and 4.5% in group B (P=1.000), and the one-year survival was 86.8% in group A and 95.5% in group B (P=0.320). Univariate analysis was performed to identify risk factors for exacerbation of postoperative ICH in the 71 patients, but none of the factors tested showed statistically significant association with the exacerbation of ICH.

Conclusions

Preoperative ICH did not appear to increase the risk of exacerbation of postoperative ICH or the early mortality rate after open heart surgery in patients with infectious endocarditis accompanied by recent septic cerebral embolism.

Patient-specific stent for hemolytic anemia due to a kinked ascending aortic graft

Hemolytic anemia after thoracic aortic surgery is rare. A 69-year-old female patient, who underwent ascending aorta replacement for acute type A aortic dissection 7 years ago, was transferred from another hospital due to hemolytic anemia necessitating regular blood transfusions. After engaging in interdisciplinary discussions, we ruled out alternative medical diagnoses and treatments, ultimately identifying the kinked aortic graft as the primary cause of hemolysis. Due to the patient's comorbidity, it was deemed high-risk to perform a redo thoracic aorta surgery for the replacement of the kinked aortic graft. Therefore, we decided to insert a patient-specific bare-metal stent into the kinked aortic graft to alleviate the kinking and promote improvement in hemolysis. We decided to perform the stent procedure under local anesthesia. The bare-metal stent was designed to be approximately 15% larger than the size of the pre-existing kinked aortic graft. A stent measuring 32 mm × 80 mm was successfully inserted and ballooned within the patient's ascending aortic graft. As a result, the patient's hemolytic condition showed gradual improvement over time. In this way, we aim to share our experience of inserting a patient-specific bare-metal stent under local anesthesia in patients who exhibit mechanical hemolysis due to a kinked aortic graft, especially when redo surgery is considered high-risk.

Granulomatous inflammation mimicking a hematoma around the replaced ascending aorta in magnetic resonance imaging: a case report

BACKGROUND

Granulomatous inflammation results from various causes including infections and allergic reactions. It can appear as high signal intensity in T2-weighted or contrast-enhanced T1-weighted magnetic resonance imaging (MRI). Here, we describe a case of granulomatous inflammation looking like a hematoma on an ascending aortic graft in MRI.

CASE PRESENTATION

A 75-year-old female was undergoing assessment for chest pain. She had a history of hemi-arch replacement for aortic dissection 10 years earlier. The initial chest computed tomography and subsequent chest MRI were suggestive of a hematoma, implying a pseudoaneurysm of the thoracic aorta, which is associated with high mortality in reoperation. Through redo median sternotomy, severe adhesion was found in the retrosternal space. A sac in the pericardial space contained yellowish and pus-like material, confirming that there was no hematoma around the ascending aortic graft. The pathologic finding was chronic necrotizing granulomatous inflammation. Microbiological tests including polymerase chain reaction analysis were negative.

CONCLUSION

Our experience indicates that an MRI finding of a hematoma at the site long after cardiovascular surgery suggests that there may be granulomatous inflammation.

Delayed Sternal Closure Using a Vacuum-Assisted Closure System in Adult Cardiac Surgery

Background

Delayed sternal closure (DSC) is a useful option for patients with intractable bleeding and hemodynamic instability due to prolonged cardiopulmonary bypass and a preoperative bleeding tendency. Vacuum-assisted closure (VAC) has been widely used for sternal wound problems, but only rarely for DSC, and its efficacy for mediastinal drainage immediately after cardiac surgery has not been well established. Therefore, we evaluated the usefulness of DSC using VAC in adult cardiac surgery.

Methods

We analyzed 33 patients who underwent DSC using VAC from January 2017 to July 2022. After packing sterile gauze around the heart surface and great vessels, VAC was applied directly without sternal self-retaining retractors and mediastinal drain tubes.

Results

Twenty-one patients (63.6%) underwent emergency surgery for conditions including type A acute aortic dissection (n=13), and 8 patients (24.2%) received postoperative extracorporeal membrane oxygenation support. Intractable bleeding (n=25) was the most common reason for an open sternum. The median duration of open sternum was 2 days (interquartile range [25th-75th pertentiles], 2-3.25 days) and 9 patients underwent VAC application more than once. The overall in-hospital mortality rate was 27.3%. Superficial wound problems occurred in 10 patients (30.3%), and there were no deep sternal wound infections.

Conclusion

For patients with an open sternum, VAC alone, which is effective for mediastinal drainage and cardiac decompression, had an acceptable superficial wound infection rate and no deep sternal wound infections. In adult cardiac surgery, DSC using VAC may be useful in patients with intractable bleeding or unstable hemodynamics with myocardial edema.

Huge Primary Pleural Cyst Mimicking an Exophytic Echinococcal Cyst: A Case Report

A 58-year-old woman presented with an incidental asymptomatic mass occupying the entire right lower thorax. A radiologic study demonstrated a huge cystic mass, initially suggestive of an exophytic echinococcal cyst. After unsuccessful catheter drainage, the patient was referred for surgery, and curative resection of the lung-, heart-, and diaphragm-compressing mass was performed under video-assisted thoracoscopic surgery. Culture studies revealed no growth of parasitic, bacterial, or fungal infections, and the final pathological result confirmed a primary pleural cyst. Thoracic cystic masses mostly manifest as bronchogenic or pericardial cysts, while primary pleural cysts have rarely been reported. We present a rare case of a huge pleural cyst that initially mimicked an echinococcal cyst.

The Neutrophil-to-Lymphocyte Ratio as a Predictor of Postoperative Outcomes in Patients Undergoing Coronary Artery Bypass Grafting

Background

The neutrophil-to-lymphocyte ratio (NLR) has been suggested as a novel predictive marker of cardiovascular disease. However, its prognostic role in patients undergoing coronary artery bypass grafting (CABG) is unclear. This study aimed to determine the association between the preoperative NLR and early mortality in patients undergoing CABG.

Methods

Cardiac surgery was performed in 2,504 patients at Seoul St. Mary's Hospital from January 2010 to December 2021. This study retrospectively reviewed 920 patients who underwent isolated CABG, excluding those for whom the preoperative NLR was unavailable. The primary endpoints were the 30- and 90-day mortality after isolated CABG. Risk factor analysis was performed using logistic regression analysis. Based on the optimal cut-off value of preoperative NLR on the receiver operating characteristic curve, high and low NLR groups were compared.

Results

The 30- and 90-day mortality rates were 3.8% (n=35) and 7.0% (n=64), respectively. In the multivariable analysis, preoperative NLR was significantly associated with 30-day mortality (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.17-1.39; p<0.001) and 90-day mortality (OR, 1.17; 95% CI, 1.07-1.28; p<0.001). The optimal cut-off value of the preoperative NLR was 3.4. Compared to the low NLR group (<3.4), the high NLR group (≥3.4) showed higher 30- and 90-day mortality rates (1.4% vs. 12.1%, p<0.001; 2.8% vs. 21.3%, p<0.001, respectively).

Conclusion

Preoperative NLR was strongly associated with early mortality after isolated CABG, especially in patients with a high preoperative NLR (≥3.4). Further studies with larger cohorts are necessary to validate these results.

Commercial porters of eastern Nepal: health status, physical work capacity, and energy expenditure

The purpose of the study was to compare full-time hill porters in eastern Nepal with part-time casual porters engaged primarily in subsistence farming. The 50 porters selected for this study in Kenja (elevation 1,664 m) were young adult males of Tibeto-Nepali origin. Following standardized interviews, anthropometry, and routine physical examinations, the porters were tested in a field laboratory for physiological parameters associated with aerobic performance. Exercise testing, using a step test and indirect calorimetry, included a submaximal assessment of economy and a maximal-effort graded exercise test. Energy expenditure was measured in the field during actual tumpline load carriage. No statistically significant differences were found between full-time and part-time porters with respect to age, anthropometric characteristics, health, nutritional status, or aerobic power. Mean VO2 peak was 2.38 +/- 0.27 L/min (47.1 +/- 5.3 ml/kg/min). Load-carrying economy did not differ significantly between porter groups. The relationship between VO2 and load was linear over the range of 10-30 kg with a slope of 9 +/- 4 ml O2/min per kg of load. During the field test of actual work performance, porters expended, on average, 348 +/- 68 kcal/hr in carrying loads on the level and 408 +/- 60 kcal/hr in carrying loads uphill. Most porters stopped every 2 min, on average, to rest their loads briefly on T-headed resting sticks (tokmas). The technique of self-paced, intermittent exercise together with the modest increase in energy demands for carrying increasingly heavier loads allows these individuals to regulate work intensity and carry extremely heavy loads without creating persistent medical problems.

Commercial porters of eastern Nepal: health status, physical work capacity, and energy expenditure

The purpose of the study was to compare full-time hill porters in eastern Nepal with part-time casual porters engaged primarily in subsistence farming. The 50 porters selected for this study in Kenja (elevation 1,664 m) were young adult males of Tibeto-Nepali origin. Following standardized interviews, anthropometry, and routine physical examinations, the porters were tested in a field laboratory for physiological parameters associated with aerobic performance. Exercise testing, using a step test and indirect calorimetry, included a submaximal assessment of economy and a maximal-effort graded exercise test. Energy expenditure was measured in the field during actual tumpline load carriage. No statistically significant differences were found between full-time and part-time porters with respect to age, anthropometric characteristics, health, nutritional status, or aerobic power. Mean VO2 peak was 2.38 +/- 0.27 L/min (47.1 +/- 5.3 ml/kg/min). Load-carrying economy did not differ significantly between porter groups. The relationship between VO2 and load was linear over the range of 10-30 kg with a slope of 9 +/- 4 ml O2/min per kg of load. During the field test of actual work performance, porters expended, on average, 348 +/- 68 kcal/hr in carrying loads on the level and 408 +/- 60 kcal/hr in carrying loads uphill. Most porters stopped every 2 min, on average, to rest their loads briefly on T-headed resting sticks (tokmas). The technique of self-paced, intermittent exercise together with the modest increase in energy demands for carrying increasingly heavier loads allows these individuals to regulate work intensity and carry extremely heavy loads without creating persistent medical problems.

Compression of protein sequence databases

We have created an algorithm for compressing a PIR database to assist individual researchers and software developers who utilize sequence database information but may not have huge storage space. The resulting compact databank contains compressed PIR information and an interface written in C which allows fast direct access to the stored information without extensive decompression of corresponding files. The databank files as well as the interface C-file can be used on both PC-compatibles and UNIX-based computers without any modifications. The interface supports all standard PIR Request Network queries (i.e. gets databank SEQ number by entry; for a defined databank SEQ number, gets specified information like: name, organism(s), keyword(s), sequence, sequence features with coordinates, etc.). In contrast with PIR Request Network, our package allows us to call PIR-contained information directly from the C programs, even on a personal computer not on a network. Our PIR-derived databank, SAGITTARIUS PIR, was implemented in the form of separate file sets. Each file set contains database information of independent types (i.e. sequences, entry indexes, organisms, etc.). On a particular computer, the available configuration of the PIR information (and storage space) can be easily changed as needed by the user without affecting retrievals of other types of stored information. Due to an original alignment-based algorithm, in the compression of protein sequences themselves, our package out-performs the well-known ZIP file compressor. For PC-compatibles, a dialogue shell is available which supports all standard PIR Request Network queries plus homology searches, alignments, etc.

Ancient splice junction shadows with relation to blocks in protein structure

Splice junction shadows (ancient exon-exon junctions) presumably reflect the existence of amino acid primary blocks which were used in the course of evolution for the construction of new proteins. The lengths of such blocks (i.e. regions between splice junctions), as the lengths of corresponding inserted or duplicated ancient exons, should be divisible by three in order to store the preexisting coding frame in the course of evolution. In this paper, we will test the hypothesis of intron-mediated recombination in a model of block molecular evolution (exon shuffling) by revealing corresponding blocks in existing database-contained coding sequences. For this purpose, we use a weight matrix prediction of ancient splice junction shadows in coding regions of the nucleotide sequences in current databases. The usage of splice junction shadows allows us to test the block evolution hypothesis in better detail in comparison with previous methods which were based only on currently existing recent exons. Our result of block length distribution at the nucleotide level shows a clear tendency to be divisible by three. At the protein level, several unexpected favorable block lengths, which are six, nine, 12 and 15 amino acids in length, were observed. Further refinements in our method for revealing splice junction shadows (structural block boundaries) might reveal peptides which probably maintain stable folds in different structures. The latter can in turn be used for protein structure prediction.

Analysis of peptides from known proteins: clusterization in sequence space

A combinatorial sequence space (CSS) model was introduced to represent sequences as a set of overlapping k-tuples of some fixed length which correspond to points in the CSS. The aim was to analyze clusterization of protein sequences in the CSS and to test various hypotheses about the possible evolutionary basis of this clusterization. The authors developed an easy-to-use technique which can reveal and analyze such a clusterization in a multidimensional CSS. Application of the technique led to an unexpectedly high clusterization of points in the CSS corresponding to k-tuples from known proteins. The clusterization could not be inferred from nonuniform amino acid frequencies or be explained by the influence of homologous data. None of the tested possible evolutionary and structural factors could explain the clusterization observed either. It looked as if certain protein sequence variations occurred and were fixed in the early course of evolution. Subsequent evolution (predominantly neutral) allowed only a limited number of changes and permitted new variants which led to preservation of certain k-tuples during the course of evolution. This was consistent with the theory of exon shuffling and protein block structure evolution. Possible applications of sequence space features found were also discussed.

Data bank homology search algorithm with linear computation complexity

A new algorithm for data bank homology search is proposed. The principal advantages of the new algorithm are: (i) linear computation complexity; (ii) low memory requirements; and (iii) high sensitivity to the presence of local region homology. The algorithm first calculates indicative matrices of k-tuple 'realization' in the query sequence and then searches for an appropriate number of matching k-tuples within a narrow range in database sequences. It does not require k-tuple coordinates tabulation and in-memory placement for database sequences. The algorithm is implemented in a program for execution on PC-compatible computers and tested on PIR and GenBank databases with good results. A few modifications designed to improve the selectivity are also discussed. As an application example, the search for homology of the mouse homeotic protein HOX 3.1 is given.

VisiCoor: a simple program for visualization of proteins

A well-drawn picture acts as an excellent metaphor for something real, and human vision provides instant, random access to any part of which the picture represents. It is in this sense that pictures can convey information more effectively than words alone. The power of the graphics work-stations available today makes visual presentation of scientific results a reality. A molecular graphics program for investigating protein structures, as well as several sample plots that show the power of the program, are presented.

Generalized tube model of biased reptation for gel electrophoresis of DNA

A theoretical analysis of the reptational motion of DNA in a gel that includes the effects of molecular fluctuations has been used to explain the main features found in experiments involving periodic inversion of the electric field. The resonance-like decrease of the electrophoretic mobility as a function of pulse duration is related to transient "undershoots" in the orientation of the molecule, in agreement with recent experimental data. These features arise from a delicate interplay of internal and center of mass motion of the molecules under pulsed field conditions, and are important for the separation of DNA molecules in the size range 0.2 to 10 million base pairs.