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Biomedical subjects

F Baumgartner

Publications and source records attributed to F Baumgartner.

At least 19 recordsLinked to original sources
PubMed2001

A point mutation in an unusual Sec7 domain is linked to brefeldin A resistance in a Plasmodium falciparum line generated by drug selection.

The malaria parasite Plasmodium falciparum has an unusual organization of its secretory compartments. As an approach to a functional identification of auxiliary proteins involved in secretion, a parasite line was generated by drug selection that is resistant to brefeldin A, an inhibitor of the secretory pathway. In the resistant line, neither protein secretion nor parasite viability were affected by the drug. The analysis of a sec7 domain, a conserved structure of guanine nucleotide exchange factors (ARF-GEF) required for the activation of ADP-ribosylation factors, revealed a single methionine-isoleucine substitution in the resistant parasite line. ARF-GEFs are key molecules in the formation of transport vesicles and the main targets of brefeldin A. The methionine residue in this position of sec7 domains is highly conserved and confers brefeldin A sensitivity. Unlike other eukaryotes that have multiple ARF-GEFs, the plasmodial genome encodes a single sec7 domain. This domain shows a distinct structural difference to all sec7 domains analysed so far; two conserved subdomains that are essential for protein function are separated in the plasmodial protein by an insertion of 146 amino acids.

ADP-Ribosylation Factors↗
PubMed1998

Reduction aortoplasty for moderately sized ascending aortic aneurysms.

Enlargement of the ascending aorta may coexist with concomitant valvular, coronary, or other cardiac diseases. If dilation is moderate (i.e., <6 cm diameter) and another cardiac procedure is being performed, we have reduced the diameter of the ascending aorta with an S-shaped incision and excision of the curves of the "S" as a modified Z-plasty. We have performed the procedure in 23 patients with concomitant procedures including aortic valve replacement in 21 (1 as a pulmonary autograft), coronary bypass in 1, and resection of subaortic stenosis in 1. There were 15 males and 8 females with a mean age of 53 years (range 8-67 years). The mean maximal preoperative diameter on transesophageal echocardiography was 5.0+/-0.7 cm (range 3.2-6.6 cm). The mean intraoperative postreduction diameter was 3.1+/-0.6 cm (range 2.1-4.1) (p<0.01). All patients tolerated their procedures well. Sixteen patients were studied by transthoracic echocardiography postoperatively. These patients had a mean intraoperative postreduction diameter of 2.9+/-0.65 cm that increased to 3.1+/-0.45 cm (p = NS) after a mean follow-up of 9.9+/-12.6 months. Of these, seven patients were studied >1 year postoperatively. Their mean intraoperative postreduction diameter of 2.9+/-0.5 cm increased to 3.1+/-0.35 cm (p = NS) after a mean follow-up of 22.1+/-9.2 months. No known recurrences of the aneurysms have occurred. We feel this technique is valid in patients with moderate aortic dilation undergoing concomitant cardiac procedures and in whom more aggressive aortic interventions are not warranted.

Adolescent↗
PubMed1997

CT guided needle localization for video-thoracoscopic resection of pulmonary nodules.

Because of its decreased invasiveness Video-Assisted Thoracoscopic Surgery (VATS) has advantages over the traditional open thoracotomy. However, resection of small and subpleural pulmonary nodules via the thoracoscope is often technically difficult or impossible. To facilitate the resection of these difficult-to-palpate lesions, a protocol was established to localize the nodules percutaneously with a fine needle under CT guidance. This method was used in four patients to localize five lung lesions identified radiographically in various lung segments. Of the four patients in the study, three presented with malignancy of the lower extremities (alveolar sarcoma, squamous cell carcinoma, and spindle cell carcinoma). In two of these patients (having alveolar sarcoma and spindle cell carcinoma primaries), the resected pulmonary lesions proved to be metastatic disease. The lesions of the other two patients were nonmalignant (actinomycosis and fibrotic granuloma). The patients with actinomycosis had two distinct lesions which were identified preoperatively with two localizations. All five lesions were able to be localized and resected with clear margins. The patients tolerated the procedures well without complication. VATS with preoperative CT guided needle localization of a subpleural nodule can be a useful diagnostic tool. Its use in therapeutic metastasectomy, nonetheless, remains controversial.

Actinomycosis↗
PubMed1997

Bilateral rudimentary first ribs as a cause of thoracic outlet syndrome.

First rib abnormalities are an uncommon cause of thoracic outlet syndrome. Cervical ribs are a much more frequent source of thoracic outlet syndrome, and in more than 95% of these patients, the symptoms are neurologic, not vascular. Rudimentary first ribs, however, uncommonly produce exclusively neurologic symptoms and usually manifest with vascular pathology. This article reviews a case of a patient with bilateral extensively neurologic thoracic outlet syndrome symptoms arising from bilateral rudimentary first ribs. The symptoms, pathologic features, and treatment, as well as an algorithm for working up patients with thoracic outlet syndrome, are discussed. Bilateral transaxillary first rib resection was curative in this patient and is the treatment of choice for either neurologic or vascular manifestations of thoracic outlet syndrome associated with rudimentary first ribs.

Female↗
PubMed1996

Extracorporeal methods of vascular control for difficult IVC procedures.

Surgical procedures in the juxtaheptic and intrapericardial inferior vena cava (IVC) are difficult because of the complexity of achieving vascular control in the area. We describe 10 patients with a variety of pathologies in this region who underwent venovenous bypass (VVB) or cardiopulmonary bypass with hypothermic circulatory arrest (CBCA). Renal cell carcinoma with IVC extension was present in three patients (with tumor extension into the right atrium in two), adrenal adenocarcinoma in one, septic IVC thrombus in one, and blunt IVC/hepatic trauma in five. Those patients without atrial involvement underwent VVB with a mean bypass time of 40 minutes (range 12-144). Those patients with tumor extension into the right atrium underwent CBCA with systemic hypothermia to 18(0)C, total body exsanguination for a bloodless field, and removal of the tumor by cavotomy and right atriotomy. The mean bypass, aortic cross-clamp, and circulatory arrest times were 152, 92, and 36 minutes, respectively. Eight of the 10 patients did well and went home within 4 weeks of surgery. Two patients died, one from metabolic sequelae of exsanguinating IVC injury (VVB) and one from sepsis 2 weeks postoperatively (CBCA).

Adult↗
PubMed1996

Modified venovenous bypass technique for resection of renal and adrenal carcinomas with involvement of the inferior vena cava.

Peripheric tumours with extension into the inferior vena cava pose difficult management problems. Venovenous bypass using a centrifugal pump to decompress the inferior vena cava may be useful adjunct during vascular isolation of the tumour. We have modified the technique by adding portal decompression to avoid visceral accumulation of toxic metabolites. We have used this technique in two patients who had intracaval extension of tumours, one renal and one adrenal carcinoma.

Adenocarcinoma↗
PubMed1996

Aortic and mitral annular remodeling using ultrasonic decalcification.

Mitral and particularly aortic valve replacements may be complicated by heavy calcification of the anulus, markedly impairing proper valve seating. From 1987 to 1996, we have used ultrasonic energy with the CUSA-device in valvular replacement to debride the aortic anulus in 90 patients and the mitral anulus in 2 patients. Annular debridement using ultrasonic decalcification is superior to other methods of debridement because it is safer, more thorough, and affords improved seating of the valve. As a result, placement of a larger valve is possible within a more compliant, wider anulus. There have been 0% incidence of paravalvular leak or valve failure. The operative mortality in our series was 1/92 (1.1%). Other than the fatality, the incidence of permanent stroke was 0%. Ultrasonic debridement to remodel the aortic and mitral valve anulus has been an invaluable adjunct in the heavily calcified anulus.

Adult↗
PubMed1996

Survival after trauma pneumonectomy: the pathophysiologic balance of shock resuscitation with right heart failure.

Emergency pneumonectomy for trauma has a high mortality. Although exsanguination is a major factor leading to death, mortality remains high even after adequate resuscitation and is thought to be related to pulmonary edema and right heart failure. We present a series of nine patients who underwent pneumonectomy at Harbor-UCLA from penetrating (7) and blunt (2) trauma. Two patients survived; three initially survived the surgery but died postoperatively of hypoxemia and right heart failure; four died intraoperatively (2 from right heart failure and 2 from exsanguination). One survivor required open cardiac massage for asystole. Careful attention to prevent volume overloading before and during trauma pneumonectomy and maintaining a negative fluid balance postoperatively may contribute to survival in these patients.

Adolescent↗
PubMed1996

Feasibility of ultrafast computed tomography in the early evaluation of coronary bypass patency.

Although ultrafast computed tomography (UFCT) is able to determine coronary artery bypass graft (CABG) patency, the clinical applicability in the early postoperative period has not been investigated. We prospectively studied 22 consecutive patients who developed angina-like chest pain, electrocardiogram (EKG) abnormalities, elevated creatine phosphokinase-MB fractions (CPK-MB fractions) (> 5%), or sudden cardiac death in the early post-CABG period. UFCT (flow mode) examinations from 4 to 28 days postoperatively were performed at six levels with 13 scans each. Indications for obtaining UFCT included chest pain (14), elevated CPK-MB (14), EKG abnormalities (10), and aborted sudden cardiac death (1). There were 78 grafts evaluated with 87 distal anastomoses. Sixty were saphenous vein grafts (SVG), 16 were left internal mammary artery (LIMA) grafts, 1 was a free right internal mammary artery (RIMA), and 1 was a right gastroepiploic artery. The 60 SVG included 9 sequential grafts with 18 distal anastomoses. UFCT identified 5 occluded nonsequential SVG and of these, 3 underwent coronary angiography confirming the UFCT findings. Visualization was inadequate to determine patency in 5/17 internal mammary artery (IMA) grafts, and all 5 were in the early part of this study and felt to be related to UFCT image protocol. All sequential grafts were determined to be patent on UFCT, although visualization was inadequate to determine if one or both of the outflow distal anastomoses were patent. Our series shows early nonsequential SVG occlusion at 5/51 (9.8%) in patients with postoperative clinical signs of possible graft occlusion. UFCT to determine the patency of proximal grafts is feasible in the early postoperative period. If UFCT is indeed a valid test for graft patency, then this study implies that most signs and symptoms of ischemia in the early postoperative period may not represent graft occlusion.

Adult↗
PubMed1995

Venovenous bypass for major hepatic and caval trauma.

Severe trauma to the liver and juxtahepatic cava require vascular isolation of the lesion. In addition to the techniques of vascular clamping and atriocaval shunting, venovenous bypass is a viable alternative to repair such injuries. We herein report its use in five consecutive patients. The technique obviates the hemodynamic sequelae of uncompensated caval occlusion and the technical dangers of atriocaval shunting.

Adolescent↗