Pancreatic cancer: treatment with neutron irradiation alone and with chemotherapy

PURPOSE: To evaluate neutron irradiation alone and with chemotherapy to treat inoperable pancreatic cancer. MATERIALS AND METHODS: Between 1977 and 1994, 173 patients (60 men, 113 women, aged 43-77 years [mean, 59 years]) with unresectable adenocarcinoma of the exocrine pancreas were treated, 106 with neutron irradiation alone and 67 with concomitant chemotherapy (fluorouracil [5-FU]). At follow-up, which was performed at 2-month intervals until death (range, 4-64 months), clinical status was recorded, noting the presence of overt metastasis and the onset of any major complications. Actuarial (Kaplan-Meier) survival tables were computed for both groups. RESULTS: For neutron irradiation alone and neutron irradiation plus chemotherapy, median survival times were 6 months and 9 months, respectively; actuarial survival rates at 3 years were 0 and 7%, respectively; major reactions (grade 3 or higher [scale of the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer]) occurred in 19 (18%) and 17 (25%) patients, respectively; and severe complications (grade 4) occurred in five (5%) and four (6%) patients, respectively. Most deaths were due to metastatic disease rather than to failure of local control. CONCLUSIONS: Neutron irradiation obliterated pancreatic adenocarcinoma at the primary site but has no effect on long-term survival. With more effective concomitant chemotherapy to prevent metastasis, local control of pancreatic cancer with neutron irradiation could lead to increased long-term survival.     

Abdominal compartment syndrome

PURPOSE: Two cases of abdominal compartment syndrome are described and the pathophysiology associated with it is reviewed. CLINICAL FEATURES: The first patient was a 46-yr-old man who sustained extensive blunt abdominal injuries following a fall. The second was a 54-yr-old man involved in a motor vehicle accident with blunt abdominal trauma. In both cases, the patients developed an extremely tense abdomen, increasing peak inspiratory pressures, hypercarbia and oliguria. Both demonstrated improvement in cardiac performance and ventilatory variables following an emergency decompressive celiotomy. CONCLUSION: Abdominal compartment syndrome results in impairment of organ function secondary to increased intraabdominal pressure. These patients require emergency decompressive celiotomy to relieve the symptoms. However, the incidence of intractable asystole and hypotension during this procedure is high and vigilance must be maintained during the release of the increased intraabdominal pressure.     

Vaccinia DNA topoisomerase I: evidence supporting a free rotation mechanism for DNA supercoil relaxation

The Vaccinia type I topoisomerase catalyzes site-specific DNA strand cleavage and religation by forming a transient phosphotyrosyl linkage between the DNA and Tyr-274, resulting in the release of DNA supercoils. For type I topoisomerases, two mechanisms have been proposed for supercoil release: (I) a coupled mechanism termed strand passage, in which a single supercoil is removed per cleavage/religation cycle, resulting in multiple topoisomer intermediates and late product formation, or (2) an uncoupled mechanism termed free rotation, where multiple supercoils are removed per cleavage/religation cycle, resulting in few intermediates and early product formation. To determine the mechanism, single-turnover experiments were done with supercoiled plasmid DNA under conditions in which the topoisomerase cleaves predominantly at a single site per DNA molecule. The concentrations of supercoiled substrate, intermediate topoisomers, and relaxed product vs time were measured by fluorescence imaging, and the rate constants for their interconversion were determined by kinetic simulation. Few intermediates and early product formation were observed. From these data, the rate constants for cleavage (0.3 s(-1)), religation (4 s(-1)), and the cleavage equilibrium constant on the enzyme (0.075) at 22 degrees C are in reasonable agreement with those obtained with small oligonucleotide substrates, while the rotation rate of the cleaved DNA strand is fast (approximately 20 rotations/s). Thus, the average number of supercoils removed for each cleavage event greatly exceeds unity (delta n = 5) and depends on kinetic competition between religation and supercoil release, establishing a free rotation mechanism. This free rotation mechanism for a type I topoisomerase differs from the strand passage mechanism proposed for the type II enzymes.     

Comparison of two oral evacuants (Citromag and Golytely) for bowel preparation before barium enema

Oral regimens for bowel preparation before barium enema examination are routinely used because of their convenience and simplicity, rather than the traditional method of colonic wash-out. We performed a prospective study comparing the side-effects and efficacy of two commonly used oral bowel evacuants (Citromag and Golytely) for bowel preparation before barium enema examination in 102 patients. The side-effects associated with the agents were assessed by analysing a questionnaire completed by the patients. There was no significant difference in the side-effects between the two agents although more patients taking Golytely (45.5%) deemed its taste unacceptable than those taking Citromag (25.9%). The results of the bowel preparation were assessed by two independent radiologists giving scores on the amount of faecal residue and the quality of mucosal coating. The amount of faecal residue was less in the Golytely group (p < 0.05). The quality of mucosal coating by barium was also better in the Golytely group than the Citromag group (p < 0.05).     

Attachment loss with postmenopausal age and smoking

To determine whether postmenopausal bone loss and factors associated with osteoporosis affect tooth retention, we examined vertebral and proximal femoral (postcranial) bone mineral density in relation to tooth loss and attachment loss in a cross-sectional study of 135 postmenopausal women (age range 41-70 yr). Women had at least 10 teeth and no evidence of moderate or severe periodontal disease. Full-mouth attachment loss measurements were made using a pressure-sensitive probe, and bone density was determined by dual-energy X-ray absorptiometry. Attachment loss was correlated with tooth loss (number of remaining teeth, radiologically determined), but not with vertebral or proximal femur bone density. Multivariate analysis showed current smoking (p = 0.01), years since menopause (p = 0.02) and the interaction of age and current smoking (p < 0.01), to be statistically significant predictors of attachment loss in our study population.     

Twenty-four-hour pharmacokinetics of rectal acetaminophen in children: an old drug with new recommendations

Oxidized low density lipoprotein (LDL) and acetyl LDL are recognized by the scavenger receptor class A type I/II (SR-AI/II) on macrophages and liver endothelial cells. Several investigators have suggested that there are additional receptors specific for oxidized LDL, but characterization of these alternate receptors for oxidized LDL and evaluation of their quantitative importance in uptake of oxidized LDL has been difficult because of overlapping ligand specificity with SR-AI/II. The purpose of this study was to determine the importance of SR-AI/II in the removal of modified LDL from the bloodstream in vivo. The clearance rate of oxidized LDL from plasma in normal mice was very rapid, and > 90% of injected dose was removed from the blood within 5 min. Clearance rates of oxidized LDL were equally high in SR-AI/II knockout mice, indicating that this receptor is not required for removal of oxidized LDL from plasma. Surprisingly, there was no difference in the clearance rate of acetyl LDL in wild-type and SR-AI/II knockout animals. The plasma clearance of radioiodinated acetyl LDL was almost fully blocked by a 50-fold excess of unlabeled acetyl LDL, but the latter only inhibited oxidized LDL clearance by approximately 5%. Both modified LDLs were cleared mostly by the liver, and there was no difference in the tissue distribution of modified LDL in control and knockout mice. Studies in isolated nonparenchymal liver cells showed that Kupffer cells accounted for most of the uptake of oxidized LDL. Extensively oxidized LDL and LDL modified by exposure to fatty acid peroxidation products were efficient competitors for the uptake of labeled oxidized LDL by SR-AI/II-deficient Kupffer cells, while acetyl LDL and malondialdehyde-modified LDL were relatively poor competitors.     

Alcohol intake of P rats is regulated by muscarinic receptors in the pedunculopontine nucleus and VTA

The CtpA protein in the cyanobacterium Synechocystis 6803 is a C-terminal processing protease that is essential for the assembly of the manganese cluster of the photosystem II complex. When fused to different chloroplast-targeting transit peptides, CtpA can be imported into isolated spinach chloroplasts and is subsequently translocated into the thylakoid lumen. Thylakoid transport is mediated by the cyanobacterial signal peptide which demonstrates that the protein transport machinery in thylakoid membranes is functionally conserved between chloroplasts and cyanobacteria. Transport of CtpA across spinach thylakoid membranes is affected by both nigericin and sodium azide indicating that the SecA protein and a transthylakoidal proton gradient are involved in this process. Saturation of the Sec-dependent thylakoid transport route by high concentrations of the precursor of the 33-kDa subunit of the oxygen-evolving system leads to a strongly reduced rate of thylakoid translocation of CtpA which demonstrates transport by the Sec pathway. However, thylakoid transport of CtpA is affected also by excess amounts of the 23-kDa subunit of the oxygen-evolving system, though to a lesser extent. This suggests that the cyanobacterial protein is capable of also interacing with components of the deltapH-dependent route and that transport of a protein across the thylakoid membrane may not always be restricted to a single pathway.