Differential host response to LPS variants in amniochorion and the TLR4/MD-2 system in Macaca nemestrina.

OBJECTIVES: Microbial-specific factors are likely critical in determining whether bacteria trigger preterm labor. Structural variations in lipopolysaccharide (LPS), a component of gram-negative bacteria, can determine whether LPS has an inflammatory (agonist) or anti-inflammatory (antagonist) effect through Toll-like receptor 4 (TLR4). Our objective was to determine whether amniochorion could discriminate between LPS variants in a nonhuman primate model. We also cloned Macaca nemestrina TLR4 and MD-2 and compared this complex functionally to the human homologue to establish whether nonhuman primates could be used to study TLR4 signaling in preterm birth. STUDY DESIGN: Amniochorion explants from M. nemestrina were stimulated with a panel of LPS variants for 24 h. Supernatants were analyzed for IL-1beta, TNF-alpha, IL-6, IL-8 and prostaglandins E2 and F2alpha. Tissue expression of TLR1, 2, 4, 6, MyD88 and NF-kappaB was studied by RT-PCR. M. nemestrina TLR4 and MD-2 genes were cloned and compared with their human counterparts in a recombinant TLR4 signaling system to determine LPS sensitivity. RESULTS: LPS variants differentially stimulated cytokines and prostaglandins, which was not related to transcriptional changes of TLR4 or other TLRs. Nearly all elements of LPS binding and TLR4 leucine-rich repeats were conserved between humans and M. nemestrina. TLR4/MD-2 signaling complexes from both species were equally sensitive to LPS variants. CONCLUSIONS: LPS variants elicit a hierarchical inflammatory response within amniochorion that may contribute to preterm birth. LPS sensitivity is similar between M. nemestrina and humans, validating M. nemestrina as an appropriate model to study TLR4 signaling in preterm birth.

Extensive thromboembolic disease of the hand and forearm: treatment with thrombolytic therapy.

Six patients with extensive hand and forearm thromboembolic disease were treated by means of intraarterial infusion of urokinase, with good clinical results. Four significant complications occurred, including a possible stroke. Embolization of pericatheter thrombus was a possible etiologic factor in this case. Antegrade brachial artery puncture should be used in the setting of prolonged upper extremity thrombolytic therapy to avoid the cerebral vasculature. Thrombolysis is an effective technique for tissue salvage in cases of inoperable hand thrombosis.

Angioplasty sites: assessment with the dual-access technique.

A technique was developed for evaluation of percutaneous transluminal angioplasty sites in arteries arising directly from the aorta. This technique involves the use of a 6-F sheath through which a 4-F pigtail catheter can be placed concurrently with a 0.032-inch guide wire that is left across the dilation site. This allows injection of adequate rates of contrast material while access is maintained, should redilation be necessary.

Iatrogenic changes at the venotomy site after percutaneous placement of the Greenfield filter.

To determine the prevalence of iatrogenic abnormalities associated with percutaneous delivery of Greenfield filters, the authors prospectively evaluated 69 peripheral veins used for filter placement in 68 patients. Of the 69 venotomy sites, 63 were not associated with preexisting thrombosis and were evaluated with compression and Doppler ultrasound within 1 week of placement and over 13-541 days. New thrombosis developed at the puncture site in nine of 63 sites (14.3%), although clinical suspicion of clot was raised in only one patient. Fifty-four sites (85.7%) showed no evidence of acute deep venous thrombosis, even though three patients had signs and symptoms suggestive of thrombosis. During the follow-up, most new thromboses resolved, yielding a 96.3% long-term patency rate. The authors conclude that postplacement increase in symptoms of venous stasis and occlusion may not correlate with placement site thrombosis. New filters should be evaluated for their ability to capture potential pulmonary emboli while maintaining caval patency and for mechanical and biologic stability because placement site complications occur at low rates and resolve in most cases.

Antibiotics and nephrostomy tube care: preliminary observations. Part II. Bacteremia.

Bacteriuria occurs after long-term drainage of the kidney. This study was designed to determine if the risk of bacteremia increases at the time of tube or stent change, whether bacteremia correlates with clinical infection, and if prophylactic antibiotics are effective in the prevention of bacteremia. One hundred four tube changes in 74 patients with percutaneous nephrostomy tubes and documented positive urine cultures were studied. Patients were arbitrarily divided into groups receiving and not receiving antibiotics before nephrostomy tube change. Asymptomatic bacteremia was documented in 11 of 104 tube changes (11%). Results of five blood cultures were positive in the group receiving antibiotics, and six cases of bacteremia occurred in the group not receiving antibiotics (P = .96). Routine nephrostomy/stent change can cause frequent, asymptomatic bacteremia in patients with colonization of bacteria in the urinary tract. Antibiotic prophylaxis was unsuccessful in preventing transient bacteremia, a factor that may have implications in patients with underlying valvular heart disease and other patients at risk for bacteremia.

Postoperative abscesses with enteric communication: percutaneous treatment.

Patients with abscesses that have enteric communication in the absence of underlying inflammatory bowel disease require modification of the usual percutaneous treatment techniques. An ongoing source of output (gastrointestinal secretions) is a complicating factor in treatment. The results of percutaneous treatment of 17 abscesses with enteric communication in 16 patients without a history of inflammatory bowel disease were reviewed. The long-term cure rate was 71%. Pancreatic involvement in abscess-bowel communication diminished the cure rate to 50% (two of four) and lengthened the duration of drainage required. The results suggest that percutaneous treatment of abscesses with enteric communication is a viable alternative to surgical intervention. Minimal morbidity and no mortality were directly attributable to percutaneous therapy in this series. When the pancreas is involved in the establishment or persistence of the abscess-bowel communication, or when the underlying bowel is diseased, the rate of success decreases.

Topographic location of the left atrium by computed tomography: reducing pulmonary artery catheter calibration error.

Two potential errors of pulmonary artery wedge pressure measurement that have received little attention are improper anatomic referencing of the transducer and nondependent placement of the pulmonary artery catheter tip. Transducers are often referenced to the midaxillary line of the supine patient. We utilized CT of the chest to determine accurately the topographic location of the left atrium to evaluate the accuracy of referencing the transducer in this position and to investigate atrial location in the lateral decubitus positions vis-à-vis external landmarks, so that more accurate referencing could be performed with a pulmonary artery catheter tip in the dependent lung. A prospective group consisting of ten patients referred for chest CT as well as retrospective review of 40 chest CT scans served as the study population. This study demonstrated a discrepancy between the perceived midaxillary line and the true location of the midleft atrium. Lateral decubitus CT scanning revealed a more readily localizable surface anatomic landmark which consistently and accurately predicts midleft atrial location. In addition, the appropriate decubitus position guarantees dependent catheter tip placement (Zone 3).

Percutaneous alternatives in nutritional support: a radiologic perspective.

As alternatives to per os feeding and nutritional support increase in number and complexity, the interventional radiologist has come to play a more significant role in the creation and maintenance of nutritional access. In very difficult access cases, the concerted effort of the nutritional surgeon and the radiologist is often required. We describe several such situations which have been successfully managed at our institution. The indications for and techniques of percutaneous reestablishment of surgically placed jejunostomy tubes, the percutaneous conversion of gastrostomy to jejunostomy tubes with retention of the gastrostomy tube, and percutaneous placement of an inferior vena caval Hickman catheter are all described in detail.

Percutaneous drainage of abscesses in patients with Crohn disease.

Up to one-quarter of patients with Crohn disease present with abdominal abscesses at some point in their illnesses, most of which have enteric communication. The efficacy of percutaneous drainage alone vs either a combined percutaneous/surgical approach or a purely surgical approach has not been established. We reviewed the results of percutaneous drainage of nine abscesses in eight patients with Crohn disease. Six of these abscesses communicated with the intestine. Those with enteric communication had temporary palliation, with improved medical status. However, all patients required definitive surgery within 7 weeks of initial drainage. Percutaneous drainage in the three patients without enteric communication resulted in a permanent cure. Our experience with this small series suggests that abscesses that have an enteric communication in patients with Crohn disease can be temporarily palliated by percutaneous drainage. However, use of this technique is unlikely to result in long-term palliation or cure. It appears that abscesses with intestinal communication in Crohn patients can be cured by percutaneous therapy alone.

Cavernous hemangioma of the liver: role of percutaneous biopsy.

Fifteen patients with liver masses detected with imaging were strongly considered clinically to have malignant disease. In each case, the possibility of a hepatic cavernous hemangioma was raised upon review of the images. With use of a 20-gauge Franseen needle, a percutaneous hepatic biopsy was performed in all 15 cases, and the diagnosis of cavernous hemangioma was confirmed. There were no complications from the biopsy. Twelve biopsies were performed on an outpatient basis. On the basis of the biopsy results, the care and treatment of each patient were significantly altered. When imaging data are not sufficient to determine that a liver mass is benign, even if the possibility of cavernous hemangioma is entertained, a percutaneous biopsy can be safely performed and can yield a specific histologic diagnosis.

Arterial rupture without balloon rupture during percutaneous transluminal angioplasty.

A 58-year-old man with severe left lower extremity claudication and rest pain underwent percutaneous transluminal angioplasty. A high-pressure balloon was inflated in an area of severe atherosclerotic narrowing. The patient complained of severe pain during inflation and had a vasovagal response. After balloon deflation, angiography displayed extravasation just inferior to the lower edge of the balloon. Immediate inflation of the balloon tamponaded the leak and allowed the patient's transfer to the operating room in stable condition. It is hypothesized that the new high-pressure balloons can overcome resistance in nondistensible arterial walls, causing rupture without balloon rupture.