Diaphragm pacing.

Diaphragm pacing is an established mode of ventilation for patients with upper motor neuron injury and preserved phrenic nerve function. Careful patient evaluation with regard to phrenic nerve function, motivation, and adequate psychosocial support is paramount for successful pacing. In properly selected individuals, full-time continuous bilateral pacing for several years has been demonstrated with advantages of increased independence and productivity, fewer tracheal tube complications, and improved phonation. Ongoing research in the field of diaphragm pacing includes refinements in electrode placement and continued testing of totally implantable devices.

Trends in the incidence of upper extremity soft tissue malignancies: a 40-year review of the Connecticut State Tumor Registry.

BACKGROUND: Although soft tissue malignancies of the upper extremity are rare, the management of these lesions has been controversial and the etiologic factors associated with the occurrence of these tumors are not well understood. The purpose of this study was to identify possible epidemiologic factors related to a recently noted rise in the occurrence of these tumors in the state of Connecticut. METHODS: The occurrence of upper extremity soft tissue tumors over the past 40 years was reviewed in the Connecticut State Tumor Registry. Demographic data collected included occupational history, residence, and presence of concomitant malignancies. Tumor histology, the extent of resection, and the incidence of recurrences were also noted. Factors associated with recurrence were identified using linear regression analysis. RESULTS: During the 40-year study period, 359 patients having upper extremity soft tissue tumors were entered into the Connecticut State Tumor Registry. An increasing trend in the number of upper extremity soft tissue tumors was evident. Many patients were involved in heavy industry or related fields. Fibrosarcoma and liposarcoma were the most common tumor types, occurring in 111 (30.3%) and 48 patients (13.2%), respectively. Sixty-seven patients presented with a synchronous second primary malignancy of the breast (49 patients), lung (seven patients), or gastrointestinal tract (five patients). Most patients (69.9%) underwent local excision of the soft tissue tumors, with fewer undergoing wide excision (20.3%) or radical excision (9.7%). Recurrence, which occurred in 144 patients, was found to be associated with extent of resection, occupational history, and concomitant malignancy. Delineation of such risk factors may be helpful in identifying patients in whom aggressive management may decrease recurrence and improve survival.

Experimental confirmation of effectiveness of fenestration in acute aortic dissection.

BACKGROUND: Aortic fenestration is used clinically to treat organ ischemia in acute descending aortic dissection. However, fenestration has not been studied experimentally. This study does so using an animal model. METHODS: Descending aortic dissection was created in six dogs, with subsequent fenestration of the infrarenal aorta. Blood flow (femoral, cephalic, and renal), blood pressure (femoral and carotid), and aortic distensibility were measured at baseline, after dissection, and after fenestration. Values were compared using paired t tests. RESULTS: Baseline femoral, cephalic, and renal arterial flows were 53+/-37, 78+/-65, and 83+/-52 mL/min, respectively. Baseline femoral and carotid pressures were 82+/-13 and 81+/-11 mm Hg, respectively. After dissection, femoral, cephalic, and renal arterial flow decreased to 20+/-21 (p < 0.05), 38+/-26, and 56+/-36 mL/min, respectively. Femoral blood pressure decreased to 28+/-17 mm Hg (p < 0.05). With fenestration, femoral, cephalic, and renal flows increased to 60+/-37 (p < 0.05), 78+/-51, and 80+/-48 mL/min, respectively. Femoral blood pressure increased to 85+/-28 mm Hg (p < 0.05). Carotid pressure remained unchanged with dissection and fenestration (77+/-17 mm Hg, 82+/-17 mm Hg, respectively). Baseline aortic distensibility (21%) decreased significantly after dissection (to 1.4%, p < 0.05) and increased after fenestration (to 12%, p < 0.05). CONCLUSIONS: Experimental aortic fenestration restored blood pressure and flow to hypoperfused organs in acute descending aortic dissection. The continued clinical application of fenestration is supported.

Use of neodymium yttrium aluminum garnet laser in long-term palliation of airway obstruction.

Palliation of acute airway obstruction using the neodymium yttrium aluminum garnet (Nd-YAG) laser was studied in 54 patients who presented over a 42-month period to the Yale cardiothoracic surgery service. Thirty-seven patients had bronchogenic carcinoma; 27 had stage IIIB or IV disease. Nine patients had endobronchial metastases from a primary nonbronchogenic carcinoma. Eight patients had benign disease. A total of 109 Nd-YAG laser tumor ablations were performed. In addition, 32 patients underwent postoperative brachytherapy. Median survival for all patients was 12 months. Patients with bronchogenic carcinoma had a median survival of five months. Fifteen of 20 patients (75%) alive at the time of follow-up reported continued palliation as shown by an improved postoperative Karnofsky score. There was no survival benefit from Nd-YAG laser ablation of endobronchial bronchogenic carcinoma; however, the Nd-YAG laser provided good to excellent palliation in the majority of patients on long-term follow-up.

PYY inhibition of VIP-stimulated ion transport in the rabbit distal ileum.

Vasoactive intestinal polypeptide (VIP) is the pathophysiologic mediator of several small intestinal hypersecretion states. VIP exerts its effect by binding mucosal receptors and ultimately increasing intracellular levels of cAMP. Peptide YY (PYY), a GI hormone concentrated in the distal ileum and colon, has been demonstrated to decrease VIP-mediated secretion in the colon through a specific Y4 mucosal receptor. Characterization of PYY's effect on VIP-stimulated small intestinal secretion may provide a basis for future therapeutic interventions. We hypothesized that ion transport in the small intestine is mediated through a novel Y receptor subtype. We performed Ussing chamber ion transport studies on rabbit ileum using VIP, PYY, and other pancreatic polypeptide (PP)-fold peptides in order to specifically examine: (1) the effects of VIP and PYY on basal and VIP-stimulated short circuit current (Isc), and (2) the changes in VIP-stimulated Isc in response to NPY, PP, leucine31,proline31 neuropeptide Y fragment, ([Leu31,Pro34]NPY) and the carboxy-terminal fragment of NPY (NPY13-36). VIP increased basal Isc in a concentration-dependent manner, while PYY decreased basal Isc. Graded concentrations of PYY decreased VIP-stimulated increases in Isc. PYY added prior to VIP had no effect on VIP-stimulated increases in ISC. Inhibition of VIP-stimulated Isc increases was seen with NPY, but not with [Leu31,Pro34]NPY, PP, or NPY13-36. This distinct pattern of binding affinity characterizes a novel Y receptor subtype. Additionally, increases in Isc by VIP despite pretreatment with PYY suggests that VIP-stimulated ion transport is mediated through mechanisms other than increases in cAMP.