Aspirin's ability to induce intestinal injury in rats is dependent on bile and can be reversed if pre-associated with phosphatidylcholine

Clinical evidence suggests that aspirin and particularly enteric-coated aspirin induce significant injury to the lower gut. We have reported that NSAID injury to the small bowel is exacerbated by bile acids and that phosphatidylcholine (PC) can protect against this damage. Using a recently described method, we intra-duodenally administered either: saline, aspirin or aspirin pre-associated with PC. The rats were euthanized 90 minutes later at which time we assessed: tissue injury morphologically, vascular permeability with i.v. administered Evan's blue and intestinal bleeding by measuring luminal hemoglobin. In a separate experiment, aspirin-induced injury was studied in rats whose bile duct was ligated either alone or in the presence of rat bile (collected from donor animals). Intra-duodenal administration of aspirin induced mucosal injury (observed histologically), an increase in vascular permeability and blood loss into the intestinal lumen, all of which could be attenuated if the NSAID was pre-associated with PC. Furthermore, using 100 mg/kg dose of aspirin it was determined that bile duct ligation (BDL) significantly reduced aspirin-induced intestinal bleeding which was not different from control rats. Lastly, it was determined that intestinal bleeding was significantly increased in rats with BDL if the aspirin was administered in rodent bile. Aspirin-induced intestinal injury and bleeding in the rat is dependent on the presence of luminal bile, which is likely attributable to it's constituent bile acids. Pre-association of aspirin with PC provides a novel therapeutic approach to significantly reduce aspirin-induced small intestinal injury and bleeding, as may occur with enteric-coated aspirin.

Osteoblast Attachment on Biomaterials as a Function of Surface Charge

Bioactive materials such as calcium phosphate ceramics and bioactive glasses enhance bone tissue formation and then bond to bone tissue. In our work, we question what particular surface feature or features of bioactive materials are responsible for the bone tissue response. In this study we have uncoupled surface charge from surface chemistry, energy, and topography and have examined osteoblast adhesion to titanium surfaces of varying surface charge. We have shown that a negative surface charge promotes osteoblast adhesion by approximately 60% over a neutral surface and that conversely, a positive surface charge inhibits osteoblast adhesion by about 20%. Continued examination of surface characteristics that control cellular responses are warranted with the eventual goal of applying those desirable surface characteristics to any structural biomaterial for bone implant or tissue engineering applications.

Penumbral mismatch is underestimated using standard volumetric methods and this is exacerbated with time

BACKGROUND AND AIMS

The mismatch between perfusion weighted images (PWI) and diffusion weighted images (DWI) using MR is increasingly being applied in patient selection for therapeutic trials. Two approaches to the calculation of the mismatch volume exist--the commonly used volumetric and the more precise co-registration method, the latter of which considers lesion topography. That there are differences in the mismatch volume analysed by each method and that these are time dependent was hypothesised.

METHODS

Patients within 48 h of ischaemic stroke onset had baseline MR PWI/DWI mismatch and T2 outcome volumes at 3 months. Volumetric mismatch volume was defined as PWI minus DWI lesion. Co-registration mismatch volume was defined as the PWI defect lesion not overlapped by the co-registered DWI lesion.

RESULTS

72 patients of median age 74.0 years were studied. Median baseline MR was at 5.9 h (IQR 3.0, 20.4 h) after stroke onset. Consistent underestimation of the mismatch volume occurred using the volumetric method (volumetric median 9.3 ml, IQR 0, 63 ml; co-registration median 20.1 ml, IQR 3.2, 69.8 ml; p<0.0001). This difference increased with time from stroke onset (p = 0.006).

CONCLUSIONS

Volumetric analysis consistently underestimates the PWI/DWI mismatch volume compared with the more precise co-registration method. This effect increases with time.

A dynamic micro-CT scanner based on a carbon nanotube field emission x-ray source

Current commercial micro-CT scanners have the capability of imaging objects ex vivo with high spatial resolution, but performing in vivo micro-CT on free-breathing small animals is still challenging because their physiological motions are non-periodic and much faster than those of humans. In this paper, we present a prototype physiologically gated micro-computed tomography (micro-CT) scanner based on a carbon nanotube field emission micro-focus x-ray source. The novel x-ray source allows x-ray pulses and imaging sequences to be readily synchronized and gated to non-periodic physiological signals from small animals. The system performance is evaluated using phantoms and sacrificed and anesthetized mice. Prospective respiratory-gated micro-CT images of anesthetized free-breathing mice were collected using this scanner at 50 ms temporal resolution and 6.2 lp mm(-1) at 10% system MTF. The high spatial and temporal resolutions of the micro-CT scanner make it well suited for high-resolution imaging of free-breathing small animals.

Mental disorders, disability and health service use amongst Vietnamese refugees and the host Australian population

OBJECTIVE

To compare the prevalence of common mental disorders, disability and health service utilization amongst Vietnamese refugees resettled in Australia for 11 years, with data obtained from a national survey of the host population.

METHOD

A stratified multistage probability household survey of 1611 Vietnamese undertaken in the state of New South Wales was compared with data from 7961 Australian-born respondents. Measures included the CIDI 2.1 and the MOS SF-12.

RESULTS

The 12-month prevalence of anxiety, depression and drug and alcohol dependence amongst Vietnamese was 6.1% compared with 16.7% amongst Australians. Vietnamese with a mental illness reported higher disability but exhibited similar levels of mental health consultation. The overall service burden of mental disorders was lower for the Vietnamese.

CONCLUSION

The findings suggest that refugee groups resettled for some time in Western countries may show sound mental health adaptation and do not necessarily impose a burden on general or mental health services.

Que faut-il attendre de la chirurgie coronaire sans circulation extracorporelle ?

Coronary artery bypass surgery with beating heart (off-pump) has become more common in the last ten years allowing seven randomized studies with at least 60 patients, comparing off-pump and on-pump coronary bypass. Anaesthesia, monitoring and haemodynamic complications are described. Randomized studies concluded to less elevation of biochemical markers of myocardial and renal injury, less hydric inflation, less cerebral microemboli, reduction of homologous blood transfusions, of hospital stay and global costs. However in low risk patients no reduction in myocardial infarction, atrial fibrillation, stroke, acute renal failure, early reoperation, surgical site infection and mortality were observed. Non-randomized studies suggest a benefit in stroke and mortality in elderly patients but the possibility of incomplete revascularization remains.

Efficacy of laparoscopic cholecystectomy in acalculous gallbladder disease: long-term follow-up

OBJECTIVE

Our aim was to determine the efficacy of laparoscopic cholecystectomy in symptomatic patients with ultrasound negative and abnormal gallbladder ejection fractions; Patients with gallbladder ejection fractions less than 35% on hepatobiliary scan were offered laparoscopic cholecystectomy.

METHODS

Between January 1995 and January 2001, 1564 patients underwent laparoscopic cholecystectomy at our institution: 256 were confirmed to have acalculous gallbladder disease by pathology report and reconfirmation of abnormal hepatobiliary scan data. A 30-day postoperative follow-up was obtained by retrospective medical record review. For this study, we contacted all 256 patients by mail questionnaire and followed up on nonresponders with telephone interviews; we also reviewed hospital records to verify preoperative symptom patterns. The survey was completed by 154 patients (60%): 48 (31%) by mail and 106 (69%) by telephone interviews. The study included 115 (75%) female and 39 (25%) male patients, and the average age was 42 years (range, 13 to 95). All hepatobiliary laboratory parameters were normal pre- and postoperatively. The survey was completed in December 2001, 1 to 5 years postoperatively (mean 3 years).

RESULTS

Preoperatively, 142 patients (92%) had right upper quadrant pain, 114 (74%) had nausea, 88 (57%) had vomiting, 120 (73%) had heartburn, and 118 (77%) had food intolerance. In a 30-day postoperative period, these numbers had reduced to 48 (37%), 14 (90%), 8 (5%), 22 (14%), and 34 (22%), respectively. had laparoscopic cholecystectomy, and 95% stated that they would recommend laparoscopic cholecystectomy to other patients.

CONCLUSION

This study shows that patients with acalculous gallbladder disease benefit from laparoscopic cholecystectomy.

Toxicity and Efficacy of Concurrent Gemcitabine and Radiotherapy for Locally Advanced Pancreatic Cancer

Gemcitabine has been demonstrated to be a potentradiosensitizer in the laboratory and in the clinic (1-7)and has proven clinical systemic activity to pancreaticcancer. Responses to systemic gemcitabine inpatients with metastatic pancreatic adenocarcinomahave been documented in phase I, phase II, and phaseIII clinical settings (8,9). Moreover, a recent randomizedtrial of gemcitabine vs 5-FU as first-linetherapy in patients with advanced pancreatic adenocarcinomademonstrated a modest median survivalbenefit (4.41 vs 5.65 mo,p= 0.0025) for those patientswho received gemcitabine compared to those whoreceived 5-FU (10). In addition, gemcitabine wasshown to improve cancer-related symptoms and performancestatus as assessed by a quantitative clinicalbenefit scale in both untreated and previouslytreated patients with metastatic adenocarcinoma ofthe pancreas (10,11). Based on these data, the FDAapproved gemcitabine as a first-line agent for patientswith advanced adenocarcinoma of the pancreas.

Antibody inhibition of cytomegalovirus: the role of natural killer and macrophage effector cells

To explore mechanisms by which antibody might inhibit cytomegalovirus (CMV), we measured the ability of intravenous CMV-IgG (CytoGam) to reduce viral yield in the presence of effector cells. Foreskin fibroblasts were infected with a clinical strain of CMV, and CytoGam was added along with effector cells consisting of either unfractionated peripheral blood mononuclear cells (PBMCs), natural killer (NK) cells, or macrophages. The combination of CytoGam and either of the effector cell types markedly inhibited established CMV infection in vitro. In addition, CytoGam combined with effector cells protected the monolayer from CMV-induced cytopathic effects. Antibody-dependent, effector cell-mediated functions may underlie the ability of CytoGam to prevent or modulate CMV infection in vivo.

Crystallographic point groups of five-dimensional space. 2. Their geometrical symbols

Our previous paper emphasized a method for obtaining the crystallographic point groups of five-dimensional space, i.e. the subgroups of the crystal family holohedries. Moreover, it recalled the names of the crystal families and the symbols of their holohedries. These results being obtained, this paper gives a geometrical symbol to each of these point groups described as Weigel-Phan-Veysseyre symbols (WPV symbols). In most cases, these symbols make it possible to reconstitute all the elements of the groups. The point symmetry operation symbols, which are the basis of the Hermann-Mauguin symbols (HM symbols) as well as of the WPV symbols, that have been defined from the cyclic groups generated by the five-dimensional point symmetry operations are recalled. The basic principles of the WPV system of crystallographic point-group symbols are explained and a list of 196 symbols of five-dimensional space out of 955 is given. All the information given by the WPV symbol of a point group is detailed and analysed through some examples and the study of the (hexagon oblique)-al crystal family. Finally, the polar point groups of five-dimensional space are specified.

Is the therapeutic index better with gemcitabine-based chemoradiation than with 5-fluorouracil-based chemoradiation in locally advanced pancreatic cancer?

PURPOSE

To retrospectively compare the toxicity and efficacy of concurrent gemcitabine-based chemoradiation with that of concurrent 5-fluorouracil (5-FU)-based chemoradiation in patients with unresectable pancreatic cancer.

PATIENTS AND METHODS

Between September 1996 and May 2000, 114 patients with localized unresectable adenocarcinoma of the pancreas were treated with concurrent chemoradiation. Locally advanced unresectable disease was defined as low-density tumor in contact with the superior mesenteric artery (SMA) or celiac artery, or occlusion of the superior mesenteric-portal venous confluence. Fifty-three patients were selected to receive gemcitabine in 7 weekly cycles (250-500 mg/m(2)) with concurrent radiotherapy (median dose 30 Gy, range 30-33 Gy in 10-11 fractions). The remaining 61 patients received continuous-infusion 5-FU (200-300 mg/m(2)) with concurrent radiotherapy (30 Gy in 10 fractions). Radiotherapy was delivered to the primary tumor and regional lymphatics. Patients receiving gemcitabine and those receiving 5-FU had a similar mean Karnofsky performance status (KPS, 89% vs. 86%), distribution of tumor grade (43% vs. 33% poorly differentiated), and percent weight loss (all p = NS). However, patients treated with gemcitabine had a significantly larger median maximum cross-sectional tumor area (TA, 8.8 cm(2) vs. 5.7 cm(2), p = 0.046) and were significantly younger (median age 60 vs. 68 years, p <0.001). Severe acute toxicity (ST) was defined as toxicity requiring a hospital stay of more than 5 days, mucosal ulceration with bleeding, more than 3 dose deletions of gemcitabine or discontinuation of 5-FU, or toxicity resulting in surgical intervention or death. Kaplan-Meier analysis was used to calculate the actuarial rate of local progression on imaging (LP), the rate of distant metastasis (DM), and the overall survival (OS) rate. The imaging was reviewed in resected patients.

RESULTS

Patients receiving gemcitabine developed significantly more ST during treatment (23% vs. 2%, p < 0.0001) than did those receiving 5-FU. Patients treated with gemcitabine had a similar 10-month LP rate (62% vs. 61%), 10-month DM rate (55% vs. 47%), 1-year OS rate (42% vs. 28%), and median OS duration (11 months vs. 9 months) to patients treated with 5 FU (all p = NS). Five patients who received gemcitabine and 1 patient who received 5-FU underwent margin-negative pancreaticoduodenectomy after chemoradiation. Three patients had a short segment (<or= 1 cm in length) of low-density tumor abutting the SMA, 1 had involvement of the common hepatic artery, and 1 had a short-segment occlusion of the superior mesenteric vein, amenable to venous resection and reconstruction. The other patient was thought to have inflammatory changes discontiguous with the tumor surrounding the SMA, which resolved after therapy. TA >10 cm(2) (p = 0.03) and poor differentiation (p = 0.07) were associated with a worse survival duration; however, other factors, such as KPS and weight loss >10% and age did not influence OS.

CONCLUSION

Despite the selection of healthier patients to receive gemcitabine, there was a significantly higher severe toxicity rate than with 5-FU. The median and 1-year survivals were not significantly different with the use of concurrent gemcitabine; however, the tumors treated were significantly larger. Additionally, a small number of patients with minimal arterial involvement whose disease met our radiographic definition of unresectable disease had margin-negative resections after treatment with gemcitabine-based chemoradiation. These possible benefits and the high rate of severe toxicity define a very narrow therapeutic index for concurrent gemcitabine-based chemoradiation given by this schedule of administration.

Toxicity and efficacy of concurrent gemcitabine and radiotherapy for locally advanced pancreatic cancer

BACKGROUND

Gemcitabine and radiotherapy are a potent combination. A clinical assessment of the therapeutic ratio for locally advanced pancreatic cancer patients has not yet been reported.

AIM OF STUDY

To assess the toxicity, survival, and pattern of failure of locally advanced pancreatic cancer patients treated with concurrent gemcitabine-based chemoradiation. Patients and Methods. Between the dates of December 1996 and August 2000 51 patients with locally advanced unresectable adenocarcinoma of the pancreas were treated with concurrent gemcitabine and radiotherapy at MDACC. Patients received 250-500 mg/m2 of gemcitabine weekly x7 over 30 min and 30-33 Gy in 10-11 fractions over two weeks to the primary tumor and regional lymphatics. Severe toxicity was defined as admission > 5 d, mucosal ulceration, > 3 dose deletions of gemcitabine or toxicity resulting in surgical intervention or that resulted in death.

RESULTS

The median survival was 11 mo. Overall, 37 of 51 patients had objective evidence of local progression. The actuarial rate of local progression rate at 9 mo was 70%. The 9-mo distant metastasis rate was 52%. Tumors > or = 10 cm2 had worse local control, distant control, and overall survival. Six patients underwent pancreaticoduodenectomy after therapy. After review of the imaging, only four of these patients had minimal arterial involvement, one was incorrectly staged, and one had initial inflammatory change on CT that resolved. Twelve of 51 (24%) patients suffered severe acute toxicity, and 17 of 51 (33%) patients were admitted for supportive care.

CONCLUSION

Concurrent gemcitabine and radiotherapy can be a very difficult combination to administer safely. Our results do not suggest a prolongation of median survival for patients with localized pancreatic cancer treated with this therapy. It is possible that gemcitabine-based chemoradiation contributes to the margin-negative resectability of a small number of patients with minimal arterial involvement, but this benefit is obscured by the frequent toxicity encountered in most patients. Locally advanced pancreatic cancer patients should continue to be enrolled on prospective studies investigating novel combinations of cytotoxic and/or biologic agents with concurrent radiotherapy.