A spectrophotometric procedure for malic acid determination in wines employing a multicommutation approach.

This work describes an automated procedure to determine L-malic acid (MA) in wine samples using a multicommuted flow analysis. The MA quantification was based on an enzymatic reaction between MA and L-malate dehydrogenase (L-MDH) in the presence of nicotinamide adenine dinucleotide (NAD(+)), producing nicotinamide adenine dinucleotide dehydrogenase (NADH), which was monitored at 340 nm. The L-MDH was immobilized on a surface of modified silica with amino groups in the presence of glutaraldehyde. For studying optimization, the system was maintained with 200 µL (288 U) of the L-MDH in 0.5 g of modified silica. Under the optimum experimental conditions, a linear response ranging from 0.1 to 1.5 g L(-1) MA (R = 0.997 and n = 7), a detection (3σ criterion) and quantification (10σ criterion) limit estimated at 0.02 and 0.06 g L(-1), respectively, a standard deviation relative of 1.8% (n = 7) for a sample of 0.5 g L(-1) MA, a sampling rate of 67 samples per hour were achieved. Analyzing ten wines samples and applying the t-test to the results found and those obtained using reference procedures (HPLC) provided no significant differences at the 95% confidence level.

Treatment of aortic valve endocarditis with the Ross operation.

OBJECTIVE: Standard treatment of patients with infective endocarditis is radical debridement and valve replacement, in cases with advanced pathology the treatment is usually root replacement with either a composite graft or a homograft. Enthusiasm for the use of the Ross operation in non-infective aortic valve disease is increasing, but use of the pulmonary autograft in the treatment of aortic valve endocarditis has been limited. The objective of this prospective study is to present the technique and results of our experience with aortic valve endocarditis treated with the Ross operation. MATERIALS AND METHODS: Since 1992 we have treated 35 patients (median age 41 years, range 6-71 years) having aortic valve endocarditis with a Ross operation. Twenty-four patients had advanced disease defined as pathology due to endocarditis extending beyond the valve cusps (13 patients) or prosthetic valve endocarditis (11 patients). Twenty-two patients had active disease at the time of surgery, and 12 had undergone one to four previous heart operations. RESULTS: There were two operative deaths (5.8%), both related to severe disease with very advanced pathology and heart failure. Intraoperative echocardiography demonstrated no or trivial autograft insufficiency in all patients. There have been no late deaths. There has been one (probable) recurrent right-sided endocarditis in a drug addict during a follow-up period of 3-56 months. One patient has been reoperated on for homograft stenosis. CONCLUSIONS: We are enthusiastic about the use of the Ross operation in aortic valve endocarditis and in younger patients with advanced pathology, it is our preferred treatment modality. Following removal of the autograft, unparalleled exposure of the left ventricular outflow tract is obtained. Even in patients with very advanced pathology the left ventricular outflow tract is usually intact, allowing autograft implantation in the standard fashion. For selected patients with simple endocarditis, the Ross operation is an attractive option on its usual merits.

One-stage repair of truncus arteriosus, CAVC, and TAPVC.

An infant with truncus arteriosus, complete atrioventricular canal, and total anomalous pulmonary venous connection successfully underwent one-stage complete repair. Residual mitral valve regurgitation required reoperation after 12 days. The patient is doing well at 6 months' follow-up. Echocardiography demonstrates no residual defects, competent atrioventricular valves, and normal pulmonary pressure. This case illustrates the potential for successful one-stage repair even of associated complex heart defects involving venous, intracardiac, and arterial pathways.

Intraoperative echocardiographic study of air embolism during cardiac operations.

BACKGROUND: Central nervous system damage remains a feared complication after heart operations. Air embolism (AE) is one of several possible causes of central nervous system damage. In previous studies, intraoperative transesophageal echocardiography (ITEE) has been used to detect AE, but identification of the periods of risk and the origin of AE is lacking. METHODS: Two groups of patients undergoing elective heart operations were studied with ITEE. Group I consisted of 15 patients undergoing true "open heart" operations, either aortic or mitral valve. Group II consisted of 15 patients undergoing coronary artery bypass grafting. RESULTS: In group I (valve operation), ITEE detected AE in all patients, particularly in the period between the release of the aortic cross-clamp and the termination of cardiopulmonary bypass. Furthermore, 12 of the 15 patients had new episodes of AE up to 28 minutes after termination of cardiopulmonary bypass. In the majority of cases, ITEE clearly demonstrated that the air originated in the lung veins and was not air retained in the heart. In group II (coronary artery bypass grafting) episodes of AE were only seen in the period between cross-clamp removal and the termination of cardiopulmonary bypass, and only in half of the patients. CONCLUSIONS: Careful standard cardiac deairing did not prevent AE caused by the delayed release of air trapped in the lung vessels. Routine use of ITEE is recommended to assess the thoroughness of deairing procedures. This will help eliminate AE or at least lead to an increased awareness of the problem of retained air. Minimizing AE during open heart operations should contribute to a reduction in central nervous system damage and improvement of intellectual function after heart operations.

Cardiac reoperation in patients with bilateral internal thoracic artery grafts.

The superior long-term patency of the left internal thoracic artery (ITA) graft is reflected in the enhanced survival of the patients who undergo the procedure, and its use has been shown to lead to a reduced need for reoperation. Evidence is accumulating that use of both ITAs at the primary operation further decreases the need for reoperation, and it is hoped that the use of other arterial conduits will augment this trend. Therefore, the popularity of bilateral ITAs and other arterial conduits in coronary artery operations is growing. However, many surgeons defer using both ITAs at the primary operation partly out of fear of the difficulties that may arise in conjunction with a possible future reoperation. Thirty-six patients underwent reoperation at The Cleveland Clinic Foundation 2 days to 13 years after an earlier bilateral ITA operation because of the progression of native disease, failure of the ITA or vein grafts, or the development of valve disease or end-stage ischemic heart disease. There were four early deaths (11%) and two late deaths, with an average follow-up of 4.3 years (range, 0 to 9.8 years). Forty-seven ITAs were patent preoperatively and 11 crossed the midline. Eleven were patent but stenosed and in need of revision or replacement. Two were damaged during reoperation; both were repaired, but one was ultimately replaced. Although the mortality associated with this procedure is relatively high and these operations are difficult, reoperation can be performed at an acceptable risk, and substantial surgical objectives can be achieved with good long-term results.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of hypertrophic cardiomyopathy by mitral valve repair and septal myectomy.

This report describes surgical treatment consisting of mitral valve repair and septal myectomy in a young patient with a combination of hypertrophic cardiomyopathy and intrinsic mitral valve disease. The posterior mitral valve leaflet was elongated and was subject to systolic anterior motion, creating left ventricular outflow tract obstruction. With the described treatment, it was possible to avoid mitral valve replacement in this patient.

Left ventricular to right atrial fistula after aortic homograft replacement for endocarditis.

The treatment is described of a patient who had severe bacterial endocarditis with aortic valve destruction and septal abscess complicated by left ventricular to right atrial fistula 3 months after aortic homograft root replacement and septal debridement and repair. The status of the aortic homograft and anatomy of the fistula were defined precisely by echocardiography, making successful repair through a right atriotomy possible without disturbing the aortic homograft and the implanted coronary arteries.

Gas explosion during diathermy gastrotomy.

The first report of rupture of the stomach due to diathermy-elicited gas explosion during gastrotomy in a patient with intestinal ischemia resulting in obstruction and jejunal and gastric dilatation is presented. In the obstructed stomach or small bowel, a proliferation of hydrogen- and methane-producing bacteria can occur, leading to the accumulation of these combustible gases in explosive concentrations. In cases of gastrointestinal tract obstruction, the diathermy knife should not be used in entering the gastrointestinal lumen.

A double-blind comparative study of prophylactic antibiotic therapy in open heart surgery: penicillin G versus vancomycin.

A double-blind clinical study was carried out comparing the prophylactic effectivity of penicillin G with vancomycin in 113 adult patients undergoing open heart surgery. Eighty of these underwent valve replacement. A total of 14 of 52 penicillin-treated patients (26.9%) and 5 of 61 vancomycin-treated patients (8.2%) suffered from postoperative infection (0.005 less than p less than 0.02). Five patients in the penicillin group and none in the vancomycin group developed postoperative wound infection (0.01 less than p less than 0.02). No significant differences in blood culture and sepsis, tracheal culture and clinical respiratory tract infection, urine culture and clinical urinary tract infection, and colonization rate were found between the 2 groups. No cases of prosthetic valve endocarditis were diagnosed. Bacteriologic culture and resistance studies did not reveal significant changes concerning the resistance patterns; in particular, the emergence of a vancomycin-resistant strain of Staphylococcus albus was not seen. A decrease in the colonization rate with Staphylococcus albus from 53% in 1975 to 1977 to 34.6% and 31.1% in the penicillin and vancomycin groups, respectively, was found in the following 2 years.