Routine antiseptic baths and MRSA decolonization: diverse approaches across Singapore's acute-care hospitals.

To determine the variation in practices on meticillin-resistant Staphylococcus aureus (MRSA) surveillance and management of MRSA-colonized patients amongst 17 acute healthcare facilities in Singapore, the Ministry of Health convened a sharing session with Infection Prevention and Control Leads. All hospitals practised close to universal MRSA entry swabbing in keeping with national policy. There were, however, major variations in the response to both positive and negative surveillance swabs across facilities including the role of routine antiseptic bathing and MRSA decolonization. Most undertaking decolonization considered its role to be in 'bioburden reduction' rather than longer-term clearance.

Large enhancement of the thermopower in Na(x)CoO2 at high Na doping.

Research on the oxide perovskites has uncovered electronic properties that are strikingly enhanced compared with those in conventional metals. Examples are the high critical temperatures of the cuprate superconductors and the colossal magnetoresistance in the manganites. The conducting layered cobaltate Na(x)CoO2 exhibits several interesting electronic phases as the Na content x is varied, including water-induced superconductivity and an insulating state that is destroyed by field. Initial measurements showed that, in the as-grown composition, Na(x)CoO2 has moderately large thermopower S and conductivity sigma. However, the prospects for thermoelectric cooling applications faded when the figure of merit Z was found to be small at this composition (0.60.75, S undergoes an even steeper enhancement. At the critical doping x(p) approximately 0.85, Z (at 80 K) reaches values approximately 40 times larger than in the as-grown crystals. We discuss prospects for low-temperature thermoelectric applications.

Fermi surface and quasiparticle dynamics of Na0.7CoO2 investigated by angle-resolved photoemission spectroscopy.

We present the first angle-resolved photoemission study of Na0.7CoO2, the host material of the superconducting NaxCoO2.nH(2)O series. Our results show a hole-type Fermi surface, a strongly renormalized quasiparticle band, a small Fermi velocity, and a large Hubbard U. The quasiparticle band crosses the Fermi level from M toward Gamma suggesting a negative sign of effective single-particle hopping t(eff) (about 10 meV) which is on the order of magnetic exchange coupling J in this system. Quasiparticles are well defined only in the T-linear resistivity (non-Fermi-liquid) regime. Unusually small single-particle hopping and unconventional quasiparticle dynamics may have implications for understanding the phase of matter realized in this new class of a strongly interacting quantum system.

Superconductivity phase diagram of Na(x)CoO2*1.3H2O.

The microscopic origin of superconductivity in the high-transition-temperature (high-T(c)) copper oxides remains the subject of active inquiry; several of their electronic characteristics are well established as universal to all the known materials, forming the experimental foundation that all theories must address. The most fundamental of those characteristics, for both the copper oxides and other superconductors, is the dependence of the superconducting T(c) on the degree of electronic band filling. The recent report of superconductivity near 4 K in the layered sodium cobalt oxyhydrate, Na(0.35)CoO2*1.3H2O, is of interest owing to both its triangular cobalt-oxygen lattice and its generally analogous chemical and structural relationships to the copper oxide superconductors. Here we show that the superconducting T(c) of this compound displays the same kind of behaviour on chemical doping that is observed in the high-T(c) copper oxides. Specifically, the optimal superconducting T(c) occurs in a narrow range of sodium concentrations (and therefore electron concentrations) and decreases for both underdoped and overdoped materials, as observed in the phase diagram of the copper oxide superconductors. The analogy is not perfect, however, suggesting that Na(x)CoO2*1.3H2O, with its triangular lattice geometry and special magnetic characteristics, may provide insights into systems where coupled charge and spin dynamics play an essential role in leading to superconductivity.

Repetitive hypoglossal nerve stimulation in myasthenia gravis.

OBJECTIVES: To assess the diagnostic efficacy of repetitive nerve stimulation (RNS) of the hypoglossal nerve in patients with myasthenia gravis (MG) and bulbar symptoms (dysphagia, dysarthria). METHODS: Twenty patients with MG and 25 normal controls had RNS of the hypoglossal nerve. All patients also had single fibre electromyography (SFEMG) of the orbicularis oculi and RNS with recordings of the nasalis, trapezius and abductor pollicis brevis muscles. RESULTS: All patients had positive SFEMG studies. Nine patients with bulbar symptoms had positive hypoglossal RNS, including 3 with negative RNS recordings in other muscles. Eleven patients with no bulbar symptoms showed negative hypoglossal RNS, including two with positive RNS recordings from other muscles. CONCLUSIONS: Abnormal RNS of the hypoglossal nerve correlates well with bulbar dysfunction and further characterises the extent of neuromuscular transmission defect in MG patients.

Conformal irradiation for hepatobiliary malignancies.

The term 'conformal irradiation' is usually used to describe the delivery of sophisticated high dose external beam irradiation (EBRT) with the aid of 3-D treatment planning and the option of both coplanar and non-coplanar beams. Data will be presented from the University of Michigan which suggest that conformal high dose EBRT (48-72.6 Gy) can be used for intrahepatic cancers, both hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (IHCC), to potentially increase local control and survival over what would be expected with lower dose EBRT. For purpose of this discussion, the term conformal irradiation will be expanded to include other techniques which conform the high dose irradiation boost volume in close proximity to unresected tumor or positive margins of resection. Data will be presented from series which utilize transcatheter iridium and intraoperative electron irradiation (IOERT) supplements to EBRT +/- concomitant chemotherapy. Each method intensifies treatment in an attempt to improve local control and survival.

Future role of radiotherapy as a component of treatment in biliopancreatic cancers.

For resected and unresectable pancreas cancers, data will be summarized from both adjuvant and locally unresectable pancreas cancer series (EBRT +/- IOERT) to demonstrate the justification of continuing to utilize chemo-irradiation as a component of treatment. The resultant improvements in local control with combined modality treatment, however, achieve only minimal improvements in survival in view of the high incidence of abdominal relapse (liver and peritoneal). Further improvement in survival may necessitate regional approaches for chemotherapy or may await advances in gene therapy. For locally unresectable and resected but residual bile duct malignancies, chemoirradiation appears to enhance tumor control and survival. Dose intensification of both modalities may be useful in improving disease control and survival. After chemoirradiation, the addition of liver transplant, in carefully selected patients who are unresectable with standard resection, may further enhance disease control and survival over what would be expected with either approach in isolation.

Adjuvant postoperative radiation therapy +/- 5-FU in resected carcinoma of the pancreas.

Ductal adenocarcinoma of the pancreas was the fourth leading cause of cancer related deaths in the United States in 1996. Pancreatic cancer is often considered a uniformly fatal disease due to its usually advanced stage at presentation. Only 5-25% of cases are resectable and surgery offers the only single modality hope of potential cure. In the past, even resectable tumors were considered incurable. Retrospective analyses of patterns of failure and prognostic variables following surgical resection, however, have resulted in randomized and non-randomized trials that have succeeded in doubling the median and long-term survival with the use of adjuvant postoperative chemoradiation. Subsequent analyzes of failure patterns following adjuvant treatment in patients with resected pancreas cancer have shown an improvement in local control, but the majority of patients continue to develop either liver and/or peritoneal metastases. To further improve survival in surgically resectable carcinoma of the pancreas, better systemic treatment and/or abdominal prophylaxis needs to be evaluated in controlled clinical trials.

External radiation therapy and transcatheter iridium in the treatment of extrahepatic bile duct carcinoma.

PURPOSE/OBJECTIVE: Review survival, prognostic factors, and patterns of failure in patients with extrahepatic bile duct (EHBD) carcinoma treated with external beam irradiation (EBRT) and transcatheter iridium. METHODS AND MATERIALS: The charts of 24 patients with EHBD cancer treated with EBRT and transcatheter boost were reviewed. All patients had transhepatic biliary tubes or endoprostheses placed. Two patients underwent hemihepatectomy with hepaticojejunostomy formation but had residual disease. Two patients had biopsy proven adenopathy. Five patients had Grade 1 adenocarcinoma, nine Grade 2, six Grade 3, and one Grade 4 disease. Median EBRT dose was 50.4 Gy delivered in 1.8 Gy/day fractions. Median transcatheter boost at 1 cm radius was 20 Gy. Nine patients received concomitant 5-Fluorouracil (5-FU) during EBRT. RESULTS: Median survival was 12.8 months (range 7.5 months to 9 years). Overall 2- and 5-year survival rates were 18.8 and 14.1%, respectively (three disease-free survivors > or =5 years). One patient is still alive without relapse 10 years from diagnosis and 5 years after liver transplantation for liver failure (no cancer in specimen, underlying sclerosing cholangitis). Two additional long-term survivors had no evidence of relapse 6.9 and 8.2 years after diagnosis. Histologic grade, lymph node status, cystic, hepatic, common hepatic or common bile duct involvement, surgical resection, radiation therapy dose, and chemotherapy did not significantly effect survival due to the number of patients analyzed. There was a trend towards improved survival with the addition of 5-FU chemotherapy (5-year survival in two of nine patients, or 22%). Eight of 24 patients (33%) demonstrated radiographic evidence of local recurrence. Distant metastases developed in 6 of 24 (25%) patients. The most common complications were tube related cholangitis (50%) and gastric/duodenal ulceration or bleeding (42%). CONCLUSION: External beam irradiation combined with a transcatheter boost can result in long-term survival of patients with EHBD cancer. Both distant metastases and local recurrence develop in 25-30% of patients despite irradiation. Survival may be improved by using chemotherapy in combination with EBRT to impact disease relapse (local and distant). Because there may be a dose response with irradiation, survival may also be improved by increasing the dose of radiation delivered by transcatheter boost. A Phase II trial is being developed using a combination of 45-50 Gy EBRT with concomitant 5-FU delivered by protracted venous infusion followed by a 25-30 Gy transcatheter boost.

Management of locally advanced breast cancer.

Multimodality therapy--i.e., surgical excision followed by appropriate systemic therapy and radiotherapy--has an established role in managing patients with locally advanced breast cancer (LABC). Preoperative chemotherapy permits optimal local control with less radical surgical intervention, although its impact on overall survival is still unclear. Definitive data are not yet available to determine the optimal sequencing of surgery and radiation therapy. Therefore, treatment should continue to be individualized. New cytotoxic agents with demonstrated activity against metastatic breast cancer (e.g., the taxanes) are being studied to determine their role in women with LABC. Preliminary data from a recently completed, small randomized trial in patients with LABC did not demonstrate a significant improvement in overall survival with high-dose chemotherapy plus stem-cell rescue, as compared with standard-dose therapy. The evaluation of biologic parameters that may predict response and survival, and of radiographic and pathologic methods to assess response, should ultimately lead to significant improvements in the management and survival of patients with locally advanced breast cancer.

Post-irradiation malignant mesothelioma.

BACKGROUND: Approximately 30 patients with malignant mesothelioma following radiotherapy have been described. Population-based studies of this occurrence have not been reported. METHODS: Patients with malignant mesothelioma of the pleura were collected. All of the patients had a prior cancer and had received radiotherapy to the region in which the malignant mesothelioma developed. Data from the National Cancer Institute's Surveillance, Epidemiology and End Results Program and the Connecticut Tumor Registry were evaluated for cases of malignant mesothelioma of the pleura occurring in patients with a previous cancer. The literature on post-irradiation malignant mesotheliomas was reviewed. RESULTS: Eight patients (4 men, 4 women) with malignant mesothelioma occurring in sites of radiotherapy for a prior tumor were identified. The mean age at diagnosis of mesothelioma was 45 years (range: 22-78 years), and the average interval between radiotherapy and the mesothelioma was 21 years (range: 11-29 years). Three of the patients had also received chemotherapy. Histologically, the mesotheliomas were epithelial in five cases, biphasic in one, and sarcomatous in one. One hundred forty-two patients were identified in the epidemiologic survey. The majority were men (89%), with a mean age for all patients of 68.5 years (range: 35-86 years) and a median latency between first cancer and mesothelioma of 4.3 years (range: 2 months-29.9 years). CONCLUSIONS: Mesotheliomas rarely develop as second malignant neoplasms. Within a large, population-based survey of patients with cancer, temporal patterns and demographic features of most second primary mesotheliomas were similar to asbestos-related tumors, although the late effects of cancer treatment might have contributed to the occurrence of cancer in some patients.

Doses to radiation sensitive organs and structures located outside the radiotherapeutic target volume for four treatment situations.

This study documents dosage to radiation sensitive organs/structures located outside the radiotherapeutic target volume for four treatment situations: (a) head and neck, (b) brain (pituitary and temporal lobe), (c) breast and (d) pelvis. Clinically relevant treatment fields were simulated on a tissue-equivalent anthropomorphic phantom and subsequently irradiated with Cobalt-60 gamma rays, 6- and 18-MV x-ray beams. Thermoluminescent dosimeters and diodes were used to measure absorbed dose. The head and neck treatment resulted in significant doses of radiation to the lens and thyroid gland. The total treatment lens dose (300-400 cGy) could be cataractogenic while measured thyroid doses (1000-8000 cGy) have the potential of causing chemical hypothyroidism, thyroid neoplasms, Graves' disease and hyperparathyroidism. Total treatment retinal (400-700cGy) and pituitary (460-1000 cGy) doses are below that considered capable of producing chronic disease. The pituitary treatment studied consisted of various size parallel opposed lateral and vertex fields (4 x 4 through 8 x 8 cm). The lens dose (40-200 cGy) with all field sizes is below those of clinical concern. Parotid doses (130-1200 cGy) and thyroid doses (350-600 cGy) are in a range where temporary xerostomia (parotid) and thyroid neoplasia development are a reasonable possibility. The retinal dose (4000 cGy) from the largest field size (8 x 8 cm2) is in the range where retinopathy has been reported. The left temporal lobe treatment also used parallel opposed lateral and vertex fields (7 x 7 and 10 x 10 cm). Doses to the pituitary gland (5200-6200 cGy), both parotids (200-6900 cGy), left lens (200-300 cGy) and left retina (1700-4500 cGy) are capable of causing significant future clinical problems. Right-sided structures received insignificant doses. Secondary malignancies could result from measured total treatment thyroid doses (670-980 cGy). Analysis of three breast/chest wall and regional nodal irradiation techniques demonstrated a 25-50% decrease in secondary lung dose with use of independent collimation compared to use of custom alloy blocking material. However, it is unlikely that a reduction in secondary dose of this magnitude would reduce the risk of treatment sequellae. In four-field "box" pelvic irradiation, secondary testes dose may result in temporary (clamshell shield) or permanent azoospermia, but is unlikely to impair androgen production.

Patterns of failure in grossly resected pancreatic ductal adenocarcinoma treated with adjuvant irradiation +/- 5 fluorouracil.

PURPOSE: Analyze patterns of failure, survival, and tolerance in patients with totally resected ductal adenocarcinoma of the pancreas treated with adjuvant irradiation alone or combined with chemotherapy. METHODS AND MATERIALS: The records of 29 patients treated with radiotherapy following curative resection of pancreas cancer at the Mayo Clinic were retrospectively reviewed. Twenty-two (76%) patients underwent a subtotal pancreatectomy (Whipple procedure), six (21%) a total pancreatectomy, and one (3.5%) a distal pancreatectomy. Twenty-six (90%) had lesions located in the head of the pancreas and three (10%) were located either in the body or tail. Twelve (41%) of the tumors were histologic Grade 3, 15 (52%) Grade 2, and two Grade 1. Contiguous invasion of adjacent tissues or organs was found in fifteen patients (52%) and seventeen (59%) had lymph node involvement. Greater than 75% of patients received more than 45 Gy, with a median dose of 54 Gy, and twenty-seven (93%) patients received concomitant 5-fluorouracil chemotherapy. RESULTS: The median survival was 22.8 months and the 2-year survival 48%. When survival was compared with that achieved with surgery alone in our institution, data suggested a doubling in both median and long-term survival with the addition of adjuvant treatment. Eighty-three percent of patients experienced tumor relapse with seventeen of 29 (59%) developing either liver metastases or peritoneal spread. In three patients, tumors recurred locally; one of one with microscopic residual disease after resection and two of 28 (7%) with negative margins (one of the two was treated with inadequate radiation portals). Patients tolerated adjuvant treatment with minimal acute toxicity consisting mostly of vomiting or nausea which, were controlled with medication in all patients. Chronic toxicity was acceptable; while 5 of 29 (17%) developed some form of possible treatment related complication, only one patient (3.5%) developed a small bowel obstruction. CONCLUSION: These results corroborate data in previous studies which have shown a survival benefit when adjuvant irradiation plus 5-fluorouracil is used in patients with completely resected ductal adenocarcinoma of the pancreas. The patterns of failure indicate that post-operative adjuvant treatment can effectively control disease locally but that future survival improvements will be achieved only by reducing the incidence of liver and peritoneal metastases.