Influence of vascular network design on gas transfer in lung assist device technology

Blood oxygenators are vital for the critically ill, but their use is limited to the hospital setting. A portable blood oxygenator or a lung assist device for ambulatory or long-term use would greatly benefit patients with chronic lung disease. In this work, a biomimetic blood oxygenator system was developed which consisted of a microfluidic vascular network covered by a gas permeable silicone membrane. This system was used to determine the influence of key microfluidic parameters-channel size, oxygen exposure length, and blood shear rate-on blood oxygenation and carbon dioxide removal. Total gas transfer increased linearly with flow rate, independent of channel size and oxygen exposure length. On average, CO(2) transfer was 4.3 times higher than oxygen transfer. Blood oxygen saturation was also found to depend on the flow rate per channel but in an inverse manner; oxygenation decreased and approached an asymptote as the flow rate per channel increased. These relationships can be used to optimize future biomimetic vascular networks for specific lung applications: gas transfer for carbon dioxide removal in patients with chronic obstructive pulmonary disease or oxygenation for premature infants requiring complete lung replacement therapy.     

Pancreas divisum: thin-section CT

Twelve patients with known pancreas divisum underwent thin-section computed tomography (CT) to determine the capability of CT to depict this pancreatic anomaly. Focal pancreatic enlargement was present in five patients. Two distinct pancreatic moieties separated by a fat cleft were noted in three patients; a fourth patient had focal atrophy in the distribution of the dorsal pancreas. The two pancreatic moieties were identified at the same craniocaudal level in all four of these patients. The dorsal duct was depicted in all 12 patients, while the short ventral duct was seen in only five of the 12 patients. Failure of the ventral and dorsal pancreatic ducts to fuse was identified in all five patients in whom both ducts were seen. CT may not enable specific diagnosis of pancreas divisum in the majority of patients. If, however, distinct pancreatic moieties or unfused ductal systems are evident, the diagnosis may be confidently suggested.     

Glomus tympanicum chemodectomas: radiographic and clinical characteristics

Glomus tympanicum chemodectomas are benign neoplasms that develop from normal glomus bodies located along the Jacobson (tympanic) nerve in the middle ear. The medical charts and radiographic studies of 55 patients with these tumors were reviewed. Women outnumbered men in a ratio of 3.5:1, and the patients' average age when they initially reported symptoms was 52 years. Tinnitus, ear pulsations, and diminished hearing were the most frequent symptoms. No patient had a second chemodectoma, and none of seven patients who were tested had elevated neuroendocrine compounds. Review of the radiographic examinations showed that direct coronal, thin-section computed tomography (CT) was the most sensitive means of demonstrating glomus tympanicum chemodectomas. Magnification angiography was also a sensitive diagnostic study, typically depicting a trapezoidal, hypervascular, middle-ear mass that appeared initially in the middle-to-late arterial phase and quickly disappeared in the venous phase. Differentiation from an aberrant internal carotid artery is critical to prevent arterial biopsy.     

Myelinated and nonmyelinated nerves: comparison of proton MR properties

The magnetic resonance (MR) relaxation rates of protons were compared in the myelinated and nonmyelinated nerves of the garfish. The long, large olfactory nerve of the garfish, as an easily accessible source of nonmyelinated axons, is uniquely suited for such a comparison. The T1 and T2 measurements revealed distinct and consistent differences between nonmyelinated olfactory nerves and myelinated optic and oculomotor nerves. Comparisons between water content, lipid content, and relaxation rates indicated that the differences in MR properties represent complex differences in the distribution and physical environment of the constituent lipid and water protons.     

The physical burden of prostate cancer

The physical burden of prostate cancer is considerable and affects quality of life in men with both localized and metastatic disease. This physical impact results as much from treatment for prostate cancer as from the disease itself. In advanced disease, although patients can experience considerable pain and discomfort from bony lesions, they also can experience bothersome fatigue and sleep disturbances from institution of hormone ablation therapy. In localized disease, although patients can have lower urinary tract symptoms from untreated prostate cancer, all aggressive treatments can result in urinary, sexual, and bowel dysfunction that can bother the patient and affect quality of life. Patients and providers must be vigilantly aware of the physical burden of prostate cancer when initiating treatment for this disease and during follow up after treatment. By being cognizant of the physical impact of prostate cancer on quality of life, providers can address patients' problems early in their course of treatment and maximize patients' HRQOL and overall satisfaction with care.     

Platelet-derived growth factor in vivo: levels, activity, and rate of clearance

Platelet-derived growth factor (PDGF) is a potent mitogen for many cultured connective tissue cells. It is present in concentrated form within the platelet alpha-granules and is believed to be released during platelet degranulation at sites of vascular injury. We have used a sensitive radioreceptor assay to measure PDGF levels in whole blood serum from normal humans [17.5 +/- 3.1 (SD) ng/mL] and baboons (2.7 +/- 1.2 ng/mL). PDGF was not detected in plasma from either species. In addition, plasma was found to substantially reduce the ability of added purified PDGF to bind to the cell surface PDGF receptor on cultured cells, suggesting that plasma may contain a PDGF-binding protein that would serve to inactivate PDGF released into plasma. Calculations of PDGF concentrations in serum have been corrected for the effects of the binding protein. 125I-PDGF injected intravenously into normal baboons was cleared rapidly from the plasma (t1/2 = two minutes). The rapid clearance of 125I-PDGF did not result from iodination damage, as purified unlabeled PDGF was cleared with comparable kinetics. The rapid clearance of purified and iodinated PDGF did not result from changes in PDGF structure during purification or from removal of PDGF-associated proteins during purification, as PDGF present in freeze-thaw lysates of fresh platelets was cleared equally rapidly. We conclude that release of PDGF at sites of vascular injury would greatly increase the local concentration of PDGF and that PDGF not localized to the site of injury would be rapidly cleared from the circulation.     

Human papillomavirus and oral disease – emerging evidence: a review

Human papillomavirus (HPV) infections have received considerable attention in recent years. Of the 120 or so known types of the virus, some cause a variety of benign wart‐like lesions of the skin and genital and oral mucosae, whilst others are aetiologically associated with cervical and anogenital cancers. Recent epidemiologic evidence suggests that HPV may also be an independent risk factor for oropharyngeal cancer. In this context it has been suggested that HPV virus may modulate the process of carcinogenesis in some tobacco and alcohol induced oropharyngeal cancers and act as the primary oncogenic agent for inducing carcinogenesis among non‐smokers. Dental practitioners have a major role in detecting all lesions of the oral mucosa caused, or possibly caused, by HPV. This paper briefly reviews the current state of knowledge of molecular and clinical aspects of HPV infections of the oral mucosa.     

Salvage radical prostatectomy: quality of life outcomes and long-term oncological control of radiorecurrent prostate cancer

PURPOSE: We review our 20-year experience with salvage radical prostatectomy to determine prognostic variables predictive of oncological control of radiorecurrent prostate cancer. Using a standardized questionnaire we also evaluate outcome data regarding the long-term sexual and urinary effects of salvage radical prostatectomy. MATERIALS AND METHODS: Between 1983 and 2002 salvage radical prostatectomy was performed in 51 patients with locally recurrent prostate cancer following definitive radiotherapy. Clinical information was obtained from a prospective database. Quality of life data were collected using the UCLA Prostate Cancer Index, a validated, patient administered instrument. RESULTS: At 5 years 47% of patients were progression-free without androgen deprivation therapy. Among patients with pT2 disease 100% were progression-free at 5 years, compared with 35% of patients with pT3N0 disease or higher and 0% of patients with node positive (pTxN+) disease (p < 0.001). Preoperative PSA 5.0 ng/ml or less was predictive of organ confined disease, and strongly associated with prolonged progression-free and overall survival (p < 0.001 and 0.01, respectively). Mean urinary function scores for patients with or without an artificial urinary sphincter compared favorably with scores reported after standard, nonsalvage prostatectomy. Sexual dysfunction was nearly uniform in patients undergoing standard salvage radical prostatectomy but implantation of a penile prosthesis was associated with a clinically significant improvement in sexual function. CONCLUSIONS: When initiated early in the course of recurrent disease, salvage radical prostatectomy provides excellent oncological control of radiorecurrent prostate cancer without the need for androgen ablation. Implantation of an artificial urinary sphincter and inflatable penile prosthesis devices in patients with postoperative urinary incontinence or erectile dysfunction results in significantly improved quality of life parameters.