Comparative analysis of commercially available kits for optimal DNA extraction from bovine fecal samples.

In the field of metagenomic research, the choice of DNA extraction methods plays a pivotal yet often underestimated role in shaping the reliability and interpretability of microbial community data. This study delves into the impact of five commercially available DNA extraction kits on the analysis of bovine fecal microbiota. Recognizing the importance of accurate DNA extraction in elucidating microbial community dynamics, we systematically assessed DNA yield, quality, and microbial composition across these kits using 16S rRNA gene sequencing. Notably, the FastDNA spin soil kit yielded the highest DNA concentration, while significant variations in quality were observed across kits. Furthermore, differential abundance analysis revealed kit-specific biases that impacted taxa representation. Microbial richness and diversity were significantly influenced by the choice of extraction kit, with QIAamp DNA stool minikit, QIAamp Power Pro, and DNeasy PowerSoil outperforming the Stool DNA Kit. Principal-coordinate analysis revealed distinct clustering based on DNA isolation procedures, particularly highlighting the unique microbial community composition derived from the Stool DNA Kit. This study also addressed practical implications, demonstrating how kit selection influences the concentration of Gram-positive and Gram-negative bacterial taxa in samples. This research highlights the need for consideration of DNA extraction kits in metagenomic studies, offering valuable insights for researchers striving to advance the precision and depth of microbiota analyses in ruminants.

Left ventricular volume reduction without ventriculectomy.

Partial left ventriculectomy (the Batista procedure) to achieve left ventricular volume reduction (LVVR) has been advocated as an alternative to cardiac transplantation in patients with end-stage dilated left ventricles. Here, we describe a new technique of LVVR that uses realignment of the papillary muscles, thus avoiding ventriculectomy, and report preliminary results. Eight patients (all male, mean age 49.3 [range 38 to 70] years) underwent LVVR between October 1998 and March 2000 as an adjunct to surgical coronary revascularization. Five were assessed with echocardiography and cardiopulmonary exercise testing before and after (mean follow-up time 267 [range 94 to 416] days) the operation. LVVR significantly improved left ventricular end-diastolic volume (254 +/- 32 to 218 +/- 36 mL, p = 0.03), left ventricular ejection fraction (20.14% +/- 1.36% to 31.28% +/- 2.32%, p = 0.007), and exercise duration (from 394 +/- 88 to 611 +/- 79 seconds, p = 0.03). A nonsignificant improvement in maximal oxygen consumption was also observed. This technique of LVVR is relatively simple to perform and is accomplished through a small apical cardiotomy. Preliminary results show an encouraging functional improvement following surgery. Future controlled studies are required to assess this novel technique further.

Mitral valve surgery using a modified superior left atrial approach.

Most surgeons use a longitudinal right lateral left atrial incision behind the inter-atrial groove for the exposure of the mitral valve, even though several other surgical techniques have been described. The shortest route to the mitral valve is, however, through the roof of the left atrium, where the incision is closest to the mitral annulus. This was first described by Meyer et al., but the approach became unpopular because of its technical difficulties and inadequacies. We have modified this technique, making it safer, easier and adaptable to any type of mitral surgery. We describe our experience with 53 patients who had mitral valve surgery using this modified approach. All of the operations were performed by the same surgeon over an 18 month period with consistently satisfactory results.

Total coronary artery revascularization through a mini-sternotomy.

Revascularization of all significantly stenosed vessels remains the goal of coronary artery bypass surgery. Recent improvements in endoscopic instruments have resulted in the evolution of selective left anterior descending artery bypass grafting through a limited anterior small thoracotomy (LAST) incision. A major limitation of this technique is the inaccessibility for complete surgical revascularization in multivessel disease. In this article, we describe a minimally invasive technique for total coronary artery revascularization that combines conventional surgical techniques with the advantages of minimally invasive surgery. We have performed total coronary revascularization in 52 patients over a period of 16 months with consistently good results.

Minimally invasive reversed Z sternotomy for aortic valve replacement.

The minimally invasive reversed Z sternotomy is a surgical approach for aortic valve operations that provides an excellent view of the aortic root and allows access to the right atrium. It confers the advantages of preservation of the sternocostal articulations and both internal thoracic arteries with no need to enter either pleural cavity. It facilitates aortic and atrial cannulation for cardiopulmonary bypass and allows access for a superior pulmonary vein cardiac vent.

Limited lower sternotomy for minimally invasive mitral valve replacement.

The minimally invasive limited lower sternotomy is a surgical approach for mitral valve operations with easy access to the left atrium. It confers the advantages of preservation of the sternocostal articulations and both internal thoracic arteries, with no need to enter either pleural cavity or resect the costal cartilages. It facilitates aortic and atrial cannulation for cardiopulmonary bypass, and allows easy access to the mitral valve through the left atrium.

Prevention of internal thoracic artery spasm.

Perioperative spasm of the internal thoracic artery is a common experience in coronary artery bypass grafting. We describe a simple method of harvesting the internal thoracic artery with improved ease of dissection that helps to prevent the arterial spasm.

Mitral valve replacement with the Carpentier-Edwards standard bioprosthesis: performance into the second decade.

From March 1978, 196 Carpentier-Edwards standard bioprostheses (stCE) were implanted in 194 patients. There were 154 isolated mitral valve replacements (MVR) and 42 aortic plus mitral valve replacements (AVR/MVR) with a mean follow-up of 7.05 (range 0-15.2) years and 7.15 (range 0-13.8) years, respectively. Freedom from structural valve failure at 10 years was 70.8% +/- 4.9% (MVR) and 59.6% +/- 11.1% (AVR/MVR). The incidence of structural valve failure increased sharply after 7 years. Freedom from thromboembolism was 83.0% +/- 3.8% (MVR) and 89.0 +/- 6.0% (AVR/MVR). Thromboembolic events were related to the presence of atrial fibrillation in patients not receiving anticoagulation. Anticoagulant-related haemorrhage was rare. Freedom from mitral valve prosthetic endocarditis at 10 years was 90.9% +/- 3.1% (MVR) and 86.1% +/- 8.4% (AVR/MVR). Prosthetic valve endocarditis was associated with more than 60% mortality. The probability of event-free survival at 10 years follow-up was 43.6% +/- 4.6% (MVR) and 33.3% +/- 8.6% (AVR/MVR). The performance of the stCE in the mitral position shows a low rate of thromboembolic events and anticoagulant-related haemorrhage, but the long-term performance of the prosthesis is unsatisfactory due to a high rate of structural valve failure. This confirms earlier reports.

Bovine internal mammary artery as a conduit for coronary revascularization: long-term results.

Graft patency after coronary artery bypass grafting depends largely on the choice of conduit. Because an increasing number of patients have insufficient or poor-quality autologous material, there is a need for a suitable synthetic graft that is readily available and easy to handle and that has good long-term patency. Early results suggest that the bovine internal mammary artery graft may meet these criteria. We have used a total of 26 such grafts in 18 patients. Postoperative angiography has been performed in 19 grafts in 14 patients, 3 to 23 months after operation; of these grafts, 3 are currently patent (15.8%, compared with 85.7% and 75.0% patency for native internal mammary artery and saphenous vein grafts in the same patients). We report the results of clotting studies and an analysis of lipid status. These patients do not, however, appear to represent any atypical group, either in terms of coagulopathy, native coronary artery size, or the type of vessel disease. Nevertheless, our poor results contrast markedly with the early enthusiasm reported from other centers.

Repair of asymptomatic aortic valve disease during other cardiac surgery.

Repair of asymptomatic aortic valve disease was performed in 12 patients (9 female, 3 male, mean age 57.5 years) undergoing other cardiac surgery. Stenosis was the predominant aortic valve lesion in 7 (group A) with a mean gradient of 33.4 mmHg and regurgitation of mean grade 1.4 was predominant in 5 (group B). Cusp debridement +/- commissurotomy was performed in 9; commissural resuspension in 6 and repair of cusp perforation in 2. Perioperative transoesophageal echocardiography was used to assess the adequacy of repair in 4 patients. Prospective precordial echocardiographic follow-up is complete (mean 4.3 months). In group A there has been a significant reduction is peak aortic pressure gradient (33.4 vs 22.1 mmHg, p less than 0.05) and in cusp thickness (2.25 to 1.64 mm, p less than 0.05). In group B the degree of incompetence has improved in 3 of the 5 patients. Three patients have worsened valve disease following repair; in all these there was mixed valve disease of rheumatic origin. Aortic valve repair of asymptomatic disease during other cardiac surgery is a feasible technique which does not accelerate the disease process in the short term. Long-term follow-up is in progress to assess the prognosis of this preventive intervention.

Conservative surgery in multiple cusp involvement in tricuspid valve endocarditis.

Tricuspid and mitral valve endocarditis caused by Staphylococcus epidermidis in a 57 year old previously healthy man with no history of drug abuse presented as bi-ventricular failure and multiple episodes of pulmonary emboli. He was treated for four weeks with intravenous antibiotics and had serial echocardiographic assessment of the vegetation on the tricuspid valve. This was followed by mitral valve replacement, local excision of vegetation from all the three cusps of the tricuspid valve, and autologous pericardial reconstruction of these cusps with functional assessment by perioperative transoesophageal echocardiography. Postoperative cardiac function was excellent and serial echocardiographic assessment confirmed satisfactory tricuspid valve function. This is believed to be the first recorded case in which autologous pericardial repair was used to reconstruct all the three cusps in a tricuspid valve after excision of vegetations.

Fatal acute left ventricular outflow obstruction due to interventricular septal haematoma--diagnosis by transoesophageal echocardiography.

We describe a case of fatal left ventricular outflow obstruction detected by intraoperative transoesophageal echocardiography. This resulted from acute haematoma formation within the interventricular septum following internal mammary artery grafting to the left anterior descending coronary artery. This unusual case highlights the emerging role of transoesophageal echocardiography in the diagnosis and management of the complications of cardiac surgery.