Biomedical subjects

Sebastian Metz

Publications and source records attributed to Sebastian Metz.

12 recordsLinked to original sources

PubMed2026

The chromosomal genome sequence of a staghorn coral, Acropora cf.  manni (Scleractinia: Acroporidae).

We present a genome assembly from a colony sample of Acropora cf. manni (staghorn coral; Cnidaria; Anthozoa; Scleractinia; Acroporidae). The assembly contains two haplotypes with total lengths of 459.26 megabases and 489.30 megabases. Most of haplotype 1 (94.39%) is scaffolded into 14 chromosomal pseudomolecules. Haplotype 2 was assembled to scaffold level. The mitochondrial genome has also been assembled, with a length of 18.48 kilobases. Metagenome binning recovered one bacterial bin from the phylum Chlamydiota.

Acropora cf. manni↗

PubMed2026

The chromosomal genome sequence of the lesser starlet coral, Siderastrea radians (Pallas, 1766) (Scleractinia: Rhizangiidae) and its associated microbial metagenome sequences.

We present a genome assembly from a specimen of Siderastrea radians (lesser starlet coral; Cnidaria; Anthozoa; Scleractinia; Rhizangiidae). The genome sequence has a total length of 807.19 megabases. Most of the assembly (94.17%) is scaffolded into 14 chromosomal pseudomolecules. The mitochondrial genome has also been assembled, with a length of 19.38 kilobases. Gene annotation of this assembly by Ensembl identified 47 051 protein-coding genes. From the metagenome data, we recovered two binned metagenomes assigned to the bacterial phylum Bacteroidota and class Bacteroidia.

Scleractinia↗

PubMed2026

The chromosomal genome sequence of the maze coral, Meandrina meandrites (Linnaeus, 1758) (Scleractinia: Meandrinidae) and its associated microbial metagenome sequences.

We present a genome assembly from a specimen of Meandrina meandrites (maze coral; Cnidaria; Anthozoa; Scleractinia; Meandrinidae). The genome sequence has a total length of 551.16 megabases. Most of the assembly (99.25%) is scaffolded into 14 chromosomal pseudomolecules. The mitochondrial genome has also been assembled, with a length of 17.2 kilobases. Gene annotation of this assembly by Ensembl identified 30 464 protein-coding genes. We recovered two bins from the metagenome data.

Meandrina meandrites↗

PubMed2007

The AppA and PpsR proteins from Rhodobacter sphaeroides can establish a redox-dependent signal chain but fail to transmit blue-light signals in other bacteria.

The AppA protein of Rhodobacter sphaeroides has the unique ability to sense and transmit redox and light signals. In response to decreasing oxygen tension, AppA antagonizes the transcriptional regulator PpsR, which represses the expression of photosynthesis genes, including the puc operon. This mechanism, which is based on direct protein-protein interaction, is prevented by blue-light absorption of the BLUF domain located in the N-terminal part of AppA. In order to test whether AppA and PpsR are sufficient to transmit redox and light signals, we expressed these proteins in three different bacterial species and monitored oxygen- and blue-light-dependent puc expression either directly or by using a luciferase-based reporter construct. The AppA/PpsR system could mediate redox-dependent gene expression in the alphaproteobacteria Rhodobacter capsulatus and Paracoccus denitrificans but not in the gammaproteobacterium Escherichia coli. Analysis of a prrA mutant strain of R. sphaeroides strongly suggests that light-dependent gene expression requires a balanced interplay of the AppA/PpsR system with the PrrA response regulator. Therefore, the AppA/PpsR system was unable to establish light signaling in other bacteria. Based on our data, we present a model for the interdependence of AppA/PpsR signaling and the PrrA transcriptional activator.

Bacterial Proteins↗

PubMed2005

Clinical experience with stentless mitral valve replacement.

BACKGROUND: Our aim is to describe the clinical experience with stentless mitral valve (SMV) replacement with special focus on the functionality of the SMV. METHODS: Fifty-two patients (68 +/- 8.5 years old; 36 female) have been prospectively evaluated since August 1997. The chordally supported SMV (Quattro) was implanted for mitral stenosis (n = 26), severe incompetence (n = 17), or mixed lesion (n = 9). Preoperative New York Heart Association class was 3.1 +/- 0.6. Twenty patients received additional intraoperative ablation therapy. Mean follow-up is 37.3 +/- 18.7 months (range, 1 to 65). RESULTS: Surgery was performed using conventional sternotomy (33) or anterolateral minithoracotomy (19). Atrial rhythm was reestablished in 17 of 20 patients. Six patients operated on early in this series required reoperation, 2 for paravalvular leakage, 2 for functional stenosis, 1 with pannus formation due to underlying rheumatoid disease, and 1 for papillary flap rupture after 5.1 years. Mortality was 1 perioperative (1.9%, nonvalve related) and 1 after reoperation due to multiorgan failure. During late follow-up (30 +/- 7 months postoperatively) 5 patients died of noncardiac causes. Regular echocardiographic control revealed good SMV function (maximum transmitral blood flow velocity 1.7 +/- 0.2 m/s; mean transmitral pressure gradient 3.9 +/- 1.2 mm Hg) and well-preserved ejection fraction postoperatively as well as at most recent follow-up. CONCLUSIONS: The clinical experience after 5.5 years of SMV implantation is promising. Preservation of annuloventricular continuity is advantageous. However, long-term durability remains to be proved.

Aged↗

PubMed2004

Prospectively randomized evaluation of stented xenograft hemodynamic function in the aortic position.

BACKGROUND: Standard stented aortic xenograft valves have not yet been compared regarding their hemodynamic function using a stratified intraoperative randomization protocol. METHODS AND RESULTS: 100 patients were prospectively included after intraoperative metric sizing of the decalcified aortic annulus. They received Mosaic (M) or Perimount (P) aortic valve replacement. Patient age was 73+/-5 years, 51 were female, and New York Heart Association (NYHA) functional class was 2.8+/-0.5. The 21-mm annulus group consisted of 5 (M)/7 (P) patients, the 23-mm annulus group of 20 (M)/20 (P), the 25-mm annulus group of 18 (M)/19 (P), and the 27-mm annulus group of 4 (M)/7 (P) patients, respectively. Hemodynamic function was evaluated using transthoracic echocardiography before discharge and at follow-up (438+/-352 days). Surgery was uncomplicated in all patients. Labeled valve sizes were 0.93 (M) and 1.05 (P) mm smaller than the annulus diameters (p=NS). In-hospital mortality was 5%, all nonvalve-related. Transvalvular blood flow velocities and transvalvular pressure gradients were significantly lower in the 25 P versus the 25 M group at baseline and in the 23 P and 25 P groups at follow-up. There was a significant regression of left ventricular mass index in all patients at follow-up. However, left ventricular mass regression was more pronounced after P aortic valve replacement. CONCLUSIONS: Labeled sizes of prosthetic heart valves implanted are smaller than the true aortic annulus. Both standard aortic xenografts compared in this prospectively randomized trial provide a sufficient hemodynamic and functional outcome.

Aged↗

PubMed2004

Restitution of sinus rhythm plus stentless mitral valve replacement at three years.

BACKGROUND AND AIM OF THE STUDY: The study aim was to examine results after stentless mitral valve (SMV) replacement (Quattro) and restitution of physiological cardiac rhythm by intraoperative left atrial ablation therapy. METHODS: Twenty patients (13 females; mean age 69.7 +/- 5.9 years) with severe degenerative mitral valve disease (six with valve stenosis, six with valve incompetence, eight with combined lesion) were prospectively evaluated since 1998. The mean NYHA functional class was 3.2 +/- 0.4, and cardiac index 1.8 +/- 0.5 l/min/m2. Ablation therapy was performed by inducing left atrial linear lesion lines to avoid reentrant circuits. RESULTS: Surgery was performed using conventional sternotomy (n = 10) or lateral minithoractomy (n = 10). Sinus rhythm was successfully restituted in 17 patients either postoperatively or in the long term (success rate 85%). However, three patients required DDD-pacemaker implantation, and another three had to be discharged with persistent atrial fibrillation. Intermittent medical therapy (sotalol or amiodarone) was required in nine patients postoperatively, in four patients at six months, and in two patients at one-year follow up. One patient was reoperated on for paravalvular leak after one year, but subsequently died due to sepsis. In the other patients, echocardiographic control proved good SMV function with atrial contraction. CONCLUSION: Restitution of physiological cardiac function is possible by combined stentless MV implantation and left atrial ablation therapy. A persistent benefit, without need for additional re-intervention, was shown at mid-term follow up.

Aged↗

PubMed2004

Early results with stentless mitral valve replacement.

BACKGROUND AND AIM OF THE STUDY: Implantation of a chordally supported stentless mitral valve (SMV) may be the strategy of choice for patients with severe degenerative mitral valve disease. Herein, the early clinical results of this surgical technique were analyzed. METHODS: Since August 1997, 52 patients (36 females, 16 males; mean age 68.0 +/- 8.5 years) each received a SMV (Quattro; St. Jude Medical Inc.) at the authors' institution. The underlying disease was predominant mitral stenosis (n = 26), incompetence (n = 17) and combined lesion (n = 9). The mean NYHA class was 3.1 +/- 0.6, left ventricular ejection fraction 64 +/-13%, and cardiac index 2.1 +/- 0.8 1/min/m2. RESULTS: SMV implantation was performed using either a conventional sternotomy (n = 33) or a lateral minithoracotomy (n = 19). The mean implanted valve size was 29.2 +/- 1.7 mm, and mean cross-clamp time 81 +/- 33 min. Reoperation was required in six patients: two for paravalvular leakage, two for functional stenosis (both 26 mm valves), in one patient for pannus formation with underlying collagenosis, and in one for papillary flap rupture at five years. One patient died perioperatively, one died after reoperation at one year, and five patients died at longer follow up, from non-cardiac causes. Hemodynamic function was shown to be normal on echocardiography. CONCLUSION: Intermediate-term results after SMV implantation were promising. Preservation of annuloventricular continuity led to good left ventricular function, but long-term durability remains to be proven.

Aged↗

PubMed2003

Midterm results after stentless mitral valve replacement.

BACKGROUND: To analyze the midterm clinical results after stentless mitral valve (SMV) replacement. METHODS AND RESULTS: Fifty one patients (68.3+/-8.4 years, 35 female) with severe mitral valve disease (stenosis 25, incompetence 17, mixed lesion 9) received a chordally supported SMV (Quattro, St. Jude Medical Inc.) since August 1997. Preoperative New York Heart Association class was 3.1+/-0.6; left ventricular ejection fraction 64+/-13%, and cardiac index 2.1+/-0.8 l/min/m2. Additional intraoperative ablation therapy was performed on 19 patients with chronic atrial fibrillation. Mean follow-up is 35.4+/-19.2 months (range 5 to 63). SMV implantation was performed using a conventional (32) or a minimally invasive (19) approach, valve size was 29+/-1.5 mm, cross-clamp duration was 81+/-33 minutes. Atrial rhythm was reestablished in 16 of 19 patients. Five patients required reoperation early in this series, two for paravalvular leakage, two for functional stenosis, and one with underlying rheumatoid disease. Mortality was one perioperative (1.96%, non-valve-related), one after reoperation as a result of multiple organ failure (MOF), and five during late follow-up (30+/-7 months postoperatively) for noncardiac causes. Regular echocardiographic control revealed good SMV function (Vmax 1.7+/-0.2m/s, P(mean) 3.9+/-1.2 mm Hg) and well-preserved ejection fraction postoperatively and at most recent follow-up. CONCLUSIONS: Midterm results after SMV implantation are promising. Preservation of the annuloventricular continuity leads to stable left ventricular function and combined with ablation therapy to physiological hemodynamics. Long-term durability remains to be proven.

Aged↗

PubMed2003

Stroke after cardiac surgery: a risk factor analysis of 16,184 consecutive adult patients.

BACKGROUND: Stroke remains a devastating complication after cardiac surgical procedures despite advances in perioperative monitoring and management. The purpose of this study was to determine the predictors of stroke in a large, contemporary cardiac surgery population. METHODS: Prospective data on 16,184 consecutive patients undergoing cardiac surgery (coronary artery bypass grafting [CABG], n = 8,917; beating heart CABG, n = 1,842; aortic valve surgery, n = 1,830; mitral valve surgery, n = 708; double or triple valve surgery, n = 381; CABG and valve surgery, n = 2,506) between April 1996 and August 2001 were subjected to univariate and multivariate analysis. Stroke was defined as any new permanent (manifest stroke) or temporary neurologic deficit or deterioration (transient ischemic attack or prolonged reversible ischemic neurologic deficit) and was confirmed by computed tomography or magnetic resonance imaging whenever possible. RESULTS: Overall incidence of stroke was 4.6% and varied between surgical procedures (CABG 3.8%; beating-heart CABG 1.9%; aortic valve surgery 4.8%; mitral valve surgery 8.8%; double or triple valve surgery 9.7%; CABG and valve surgery 7.4%). Of 63 patient-specific and treatment variables, 54 were found to have a significant univariate association with postoperative stroke. Multivariable analysis revealed 10 variables that were independent predictors of stroke: history of cerebrovascular disease, peripheral vascular disease, diabetes, hypertension, previous cardiac surgery, preoperative infection, urgent operation, CPB time more than 2 hours, need for intraoperative hemofiltration, and high transfusion requirement. Beating heart CABG was associated with a lower incidence of stroke in this multivariable analysis. CONCLUSIONS: Identification of predictors for stroke is important for understanding the pathogenesis of this devastating complication as well as for developing preventative strategies. Although retrospective analyses can be subject to selection bias we believe beating heart CABG is associated with a lower incidence of stroke and may therefore improve patient outcomes.

Adult↗

PubMed2003

Estrogen receptor expression and synthesis in the human internal thoracic artery.

The inhibition of vascular smooth muscle cell proliferation is mediated through two intracellular estrogen receptors (ERs), ER-alpha and ER-beta. Deletion variants of ER-alpha have been decribed for cultures of smooth muscle cells. The internal thoracic artery is frequently used as coronary artery bypass graft, yet neither has it been studied for the expression of ER subtypes nor for the synthesis of the ERs in morphologically hetergeneous smooth muscle cells. Using nested RT-PCR, we have demonstrated the mRNA for ER-alpha splicing variants in intact human internal thoracic arteries. The 7A deletion variant occurred in 8 out of 12 cases, the full-length transcript in three cases. The full-length transcript was always found for the ER-beta. Immunolocalization revealed ER-positive nuclei in the desmin-positive subset of smooth muscle cells, but not in cytokeratin (CK)-positive cells of the thickened intima. Morphological evidence is presented suggesting that ER synthesis is high in the tunica media when cell proliferation of smooth muscle cells is increased. We conclude that, in internal thoracic arteries, the 7A deletion variant of ER-a occurs in 75%, whereas the full-length transcript is found in all cases. The significance remains unclear.

Alternative Splicing↗

PubMed2002

Endoscopic internal thoracic artery dissection leads to significant reduction of pain after minimally invasive direct coronary artery bypass graft surgery.

BACKGROUND: The aim of this study was to evaluate postoperative pain levels after endoscopic versus conventional internal thoracic artery (ITA) dissection for minimally invasive direct coronary artery bypass graft surgery (MIDCABG) surgery. Results were compared with pain levels associated with conventional cardiac bypass operations through a median sternotomy. METHODS: Of 190 patients included in this prospective study, 24 patients had endoscopic ITA takedown (MIDCABG-endo) using the da Vinci telemanipulator followed by a manual coronary anastomosis through a left minithoracotomy. A conventional MIDCABG operation (MIDCABG-conv) was performed in 73 patients with ITA preparation under direct vision. Postoperative pain levels after conventional CABG through a median sternotomy (CABG-conv, n = 93) served as controls. A standarized questionnaire including visual analog scale (VAS) was used for prospective pain assessment from POD 1 to 7. RESULTS: Pain levels (VAS) declined in all groups from POD 1 to 7. Overall pain levels were significantly lower in the MIDCABG-endo group as compared with MIDCABG-conv and CABG-conv groups, respectively (p < 0.001, general linear model). There was no significant difference between the MIDCABG-conv and CABG-conv (p = not significant, general linear model) groups. Furthermore, patients after MIDCABG-endo required fewer nonsteroidal anti-inflammatory drugs and opioid medications, postoperatively. CONCLUSIONS: An endoscopic ITA takedown in MIDCABG surgery leads to significantly reduced postoperative pain levels possibly because of less rib retraction.

Aged↗