Replacing the Anterior Mitral Valve Leaflet With Autologous Jugular Vein in a Sheep Model.

BACKGROUND: This study evaluated the use of an autologous vein graft, supported by expanded polytetrafluoroethylene (ePTFE) chordae tendineae, to replace an anterior mitral valve leaflet. METHODS: A double-layered autologous jugular vein graft, supported by ePTFE chords, was used to create an anterior mitral valve leaflet in 21 sheep. Mitral valve function was monitored with echocardiography for up to 10 months. Surviving sheep were euthanized between 6 and 10 months later, and vein implants were examined histologically. RESULTS: One sheep died intraoperatively. Fourteen sheep had trace to mild mitral regurgitation (MR), 5 had mild to moderate MR, and 1 had moderate to severe MR. Ten sheep died between 2 days and 6.2 months. Echocardiography at 6 months showed MR progression in 8 of 11 sheep. The vein leaflet developed intimal fibroplasia and fibrous proliferation in response to the increased stress on the tissue, but the vein remained flexible without shortening or contracture. The 6- to 10-month vein implants showed viability with intact endothelium, myofibroblasts, collagen, and elastin. A normal healing pattern was seen at the suture lines, and no calcification was observed in the vein leaflet apart from the ePTFE sutures. CONCLUSIONS: Autologous vein has the potential to function as a mitral valve leaflet substitute because it adapted morphologically and remained viable in the intracardiac position. Technical refinement in creating and implanting the leaflet is needed to improve the progression of MR.

The indications and role of paediatric bronchoscopy in a developing country, with high prevalence of pulmonary tuberculosis and HIV.

BACKGROUND: Bronchoscopy, an important investigation for the diagnosis and management of respiratory diseases, is widely used in high income countries. There is limited information on value of paediatric bronchoscopy in low and middle income countries (LMIC). AIMS AND OBJECTIVES: Aim was to describe the indications, findings and complications of bronchoscopy in a middle income country with a high prevalence of tuberculosis and HIV. METHODOLOGY: A retrospective analysis of a database over a 3.5 year period. RESULTS: A total of 509 bronchoscopies were performed on neonates (2.3%) and children (median age = 18 months) of which 5.1% were HIV-infected. The main indications were: possible large airway compression 40%, complicated pneumonia (25%) and persistent stridor (15%). Pathology was observed in 64% of bronchoscopies. The most findings were lymph node compression of the airways (21%), and upper airway pathology (12%). Interventional procedures were performed in 112 cases (22%), the commonest being foreign bodies removal (30%), endobronchial lymph node enucleation (30%) and transbronchial needle aspiration (20%). No major complications. CONCLUSION: The diagnostic yield of paediatric bronchoscopy did not differ from high income countries emphasising the importance of paediatric bronchoscopy in the management of childhood lung disease in LMICs.

A new technique for repair of a dislocated sternoclavicular joint using a sternal tension cable system.

An unstable anterior or posterior sternoclavicular joint dislocation can cause severe morbidity with poor shoulder movement and strength. These dislocations need to be repaired, which can be challenging. Many different procedures have been described to obtain a stable joint fixation with varying results. We report a new technique for repairing a sternoclavicular joint dislocation by using a figure-of-eight sternal cable system. This procedure is relatively simple and reproducible to create a stable and functional sternoclavicular joint.

Expression, purification, biochemical and pharmacological characterization of a recombinant aprotinin variant.

Aprotinin (GAS 9087-70-1) is known as a potent inhibitor of serine proteases such as trypsin, plasmin, tissue and plasma kallikrein. In this study, an aprotinin variant was designed by means of rationale mutagenesis that differs from aprotinin by two amino acids in the active site and by seven amino acids in the backbone. The recombinant protein is expressed in a secretory yeast system enabling large scale production. A purification procedure was developed to yield high amounts of pure and correctly processed aprotinin variant. The changes in the active site of the aprotinin variant increase the potency towards inhibition of plasma kallikrein whereas the inhibition of plasmin is only marginally reduced. The net charge of the molecule is reduced from the basic (IP 10.5) to the neutral range (IP 5.6). The recombinant aprotinin variant shows a decrease of immunogenicity in several models. No cross-reactivity with human and rabbit antibodies directed against aprotinin was observed both in in vivo and in ex vivo studies. In addition, the variant is more potent in a rat brain edema model of acute subdural hematoma compared to aprotinin.

Allele frequencies for glutathione S-transferase and N-acetyltransferase 2 differ in African population groups and may be associated with oesophageal cancer or tuberculosis incidence.

Glutathione S-transferase (GST) and arylamine N-acetyltransferase 2 (NAT2) metabolise many environmental and chemotherapeutic agents, which influence susceptibility to disease. Polymorphisms in these enzymes result in different host phenotypes and contribute to different disease profiles or responses to toxic or chemotherapeutic agents, depending on their frequency in different populations. GST and NAT2 polymorphisms were investigated in different population groups, including African populations, and a range of allelic frequencies have been observed. The GSTM1 null genotype frequency, reported in this paper in two South African ethnic groups, is the lowest reported (0.19-0.21). In contrast, these same groups have a high GSTT1 null frequency (0.41-0.54), which is considerably higher than in African-Americans, or other Africans. The GSTT1 null frequency is comparable to the Chinese, a population with a very high oesophageal cancer incidence, similar to that in the African group. The frequency of the GSTPi Val105 variant in the South African Xhosas was also high (0.53), differing significantly from the low frequency in other Africans. These variants could therefore be associated with high cancer susceptibility. In addition, the high proportion of NAT2 "fast" alleles may partially explain the high tuberculosis prevalence in South Africans, due to reduced isoniazid efficacy in the presence of rapid acetylation.

Delayed pericardial effusion following stab wounds to the chest.

INTRODUCTION: Delayed pericardial effusion following penetrating cardiac trauma has not been commonly reported, and the exact incidence remains unknown. It was more common before 1960, when pericardiocentesis was still a popular treatment for stable patients presenting with a stab wound to the heart. MATERIAL AND METHODS: During an 8-year period, 24 patients were diagnosed with delayed pericardial effusions following a recent stab wound over the chest. Nine patients had been initially treated at our trauma unit, and the remaining 15 patients were referred by a peripheral clinic. RESULTS: Diagnosis was confirmed by cardiac ultrasound or echocardiogram. Sixteen patients were adequately treated by subxiphoid drainage. Sternotomy was performed in five patients, left thoracotomy in two and right thoracotomy in one patient. No actively bleeding injuries were found. Three patients had active infection in the pericardial space. Fever, pleural effusions and ascites were common associated findings. Additional procedures performed included laparotomy for acute abdominal pain in two patients (both negative), and simultaneous drainage of a pleural empyema. Two patients with staphylococcal pericardial infections required subsequent pericardiectomy. SUMMARY: The diagnosis of a penetrating cardiac patient may be missed in a stable patient, and patients may present with delayed pericardial effusions and tamponade. Post pericardiotomy syndrome may be the most common cause of delayed pericardial effusion, followed by sepsis. Subxiphoid pericardial window is an adequate form of treatment. Recent literature reveals that occult cardiac injury is not uncommon, thus a case should be made to actively investigate all patients with precordial stab wounds with cardiac ultrasound or echocardiogram.

Pericardial rupture and cardiac herniation after blunt chest trauma.

Pericardial rupture after blunt chest trauma is rare and is associated with a high mortality rate. We describe a patient with traumatic pericardial rupture and cardiac herniation who was successfully treated surgically. Traumatic pericardial rupture is difficult to diagnose preoperatively but should be suspected whenever there is severe blunt chest trauma. If pericardial rupture is not recognized and treated promptly it could be fatal owing to cardiac herniation.