Spatially-resolved analyses of aerodynamic fallout from a uranium-fueled nuclear test.

Five silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Several samples display compositional heterogeneity suggestive of incomplete mixing between major elements and natural U ((238)U/(235)U = 0.00725) and enriched U. Samples exhibit extreme spatial heterogeneity in U isotopic composition with 0.02 < (235)U/(238)U < 11.84 among all five spherules and 0.02 < (235)U/(238)U < 7.41 within a single spherule. In two spherules, the (235)U/(238)U ratio is correlated with changes in major element composition, suggesting the agglomeration of chemically and isotopically distinct molten precursors. Two samples are nearly homogenous with respect to major element and uranium isotopic composition, suggesting extensive mixing possibly due to experiencing higher temperatures or residing longer in the fireball. Linear correlations between (234)U/(238)U, (235)U/(238)U, and (236)U/(238)U ratios are consistent with a two-component mixing model, which is used to illustrate the extent of mixing between natural and enriched U end members.

Detection of anthrax toxin genetic sequences by the solid phase oligo-probes.

PURPOSE: There is an urgent need to detect a rapid field-based test to detect anthrax. We have developed a rapid, highly sensitive DNA-based method to detect the anthrax toxin lethal factor gene located in pXO1, which is necessary for the pathogenicity of Bacillus anthracis. MATERIALS AND METHODS: We have adopted the enzyme-linked immunosorbent assay (ELISA) so that instead of capturing antibodies we capture the DNA of the target sequence by a rapid oligo-based hybridization and then detect the captured DNA with another oligoprobe that binds to a different motif of the captured DNA sequences at a dissimilar location. We chose anthrax lethal factor endopeptidase sequences located in pXO1 and used complementary oligoprobe, conjugated with biotin, to detect the captured anthrax specific sequence by the streptavidin-peroxidase-based colorimetric assay. RESULT: Our system can detect picomoles (pMoles) of anthrax (approximately 33 spores of anthrax) and is >1000 times more sensitive than the current ELISA, which has a detection range of 0.1 to 1.0 ng/mL. False positive results can be minimized when various parameters and the colour development steps are optimized. CONCLUSION: Our results suggest that this assay can be adapted for the rapid detection of minuscule amounts of the anthrax spores that are aerosolized in the case of a bioterrorism attack. This detection system does not require polymerase chain reaction (PCR) step and can be more specific than the antibody method. This method can also detect genetically engineered anthrax. Since, the antibody method is so specific to the protein epitope that bioengineered versions of anthrax may not be detected.

Patient experiences of colonoscopy, barium enema and CT colonography: a qualitative study.

Previous studies of patient experience with bowel screening tests, in particular CT colonography (CTC), have superimposed global rating scales and not explored individual experience in detail. To redress this, we performed qualitative interviews in order to characterize patient expectations and experiences in depth. Following ethical permission, 16 patients undergoing CTC, 18 undergoing colonoscopy and 15 undergoing barium enema agreed to a semi-structured interview by a health psychologist. Interviews were recorded, responses transcribed and themes extracted with the aim of assimilating individual experiences to facilitate subsequent development and interpretation of quantitative surveys of overall satisfaction with each diagnostic test. Transcript analysis identified three principal themes: physical sensations, social interactions and information provision. Physical sensations differed for each test but were surprisingly well tolerated overall. Social interactions with staff were perceived as very important in colouring the whole experience, particularly in controlling the feelings of embarrassment, which was critical for all procedures. Information provision was also an important determinant of experience. Verbal feedback was most common during colonoscopy and invariably reassuring. However, patients undergoing CTC received little visual or verbal feedback and were often confused regarding the test outcome. Barium enema had no specific advantage over other tests. Qualitative interviews provided important perspectives on patient experience. Our data demonstrated that models describing the quality of medical encounters are applicable to single diagnostic episodes. Staff interactions and information provision were particularly important. We found advantages specific to both CTC and colonoscopy but none for barium enema. CTC could benefit greatly from improved information provision following examination.

Influence of cinnamon and clove essential oils on the D- and z-values of Escherichia coli O157:H7 in apple cider.

Escherichia coli O157:H7 has become a concern within the apple cider industry. The purpose of this study was to screen several essential oils and isolated components for antimicrobial activity against E. coli O157:H7 in tryptic soy broth at neutral and acidic pH and to assess the effect of these additives on the D-value of E. coli O157:H7 in apple cider in combination with mild heat treatments. Cinnamon oil and clove oil strongly inhibited the growth of E. coli O157:H7 at neutral and acidic pH, (R)-(-)-carvone and (S)-(-)-perillaldehyde were moderately inhibitory at both pH 7.2 and pH 4.5, and citral and geraniol displayed moderate activity at pH 4.5 only. Lemon oil, methyl jasmonate, and p-anisaldehyde displayed little or no antibacterial activity. A synergistic effect between the essential oils and the lower pH of the growth medium was evident by consistently lower MICs at pH 4.5. Cinnamon and clove oils (0.01%, vol/vol) were further tested in apple cider in combination with mild heat treatments for the practical control of E. coli O157:H7 in apple cider. The addition of either essential oil resulted in lower D-values than those for cider alone, suggesting a synergistic effect and the potential efficacy of a mild heat treatment for apple cider.

Role of priming stresses and Hsp70 in protection from ischemia-reperfusion injury in cardiac and skeletal muscle.

Ischemia-reperfusion injury limits the survival of muscle involved in tissue trauma or transfers during microsurgical reconstruction. Priming stresses such as ischemic preconditioning or mild hyperthermia have frequently been associated with improved survival of ischemic-reperfused cardiac muscle, such protection coinciding with induction of the stress-related heat shock protein 70 (Hsp70). Little is known about the response of skeletal muscle to priming stresses. This review summarizes the current knowledge on the use of priming stresses as protective strategies against the consequences of ischemia-reperfusion in cardiac and skeletal muscle and the potential role of Hsp70.

Drug users talk about HIV testing: motivating and deterring factors.

Injection drug use plays a critical role in the spread of HIV/AIDS, with an estimated 19,000 drug users infected each year. Counselling and testing services can be an important gateway for engaging HIV-infected individuals into medical care and can positively influence the preventive behaviours of IDUs. This study seeks to document and understand the complexity and range of motivations and deterrents to HIV testing among IDUs. Participants were recruited using a convenience sampling method. Interviews consisted of a qualitative guide and a quantitative survey to collect HIV testing histories, sex and drug risk behaviours, and demographic information. Interview data was coded and content analyzed to identify emerging themes and clarify the processes that drug users employ in deciding whether or not to test. Sixty-six drug users were interviewed. The sample reported a median of four lifetime HIV tests. Participants described a range of motivating and deterring factors to HIV testing across personal, interpersonal and structural categories. Drug users' decision to test is influenced by a complex network of factors. Better understanding of these motivators and deterrents can help providers develop a more holistic approach to targeting this high-risk population for HIV prevention efforts.

Hyperalgesia due to nerve injury-role of peroxynitrite.

We carried out a partial ligation of the sciatic nerve in rats to induce nerve injury and neuropathic hyperalgesia. We showed that nitrotyrosine, a marker of peroxynitrite activity, was formed after partial nerve injury. Double-labelling immunohistochemistry showed that nitrotyrosine-immunoreactive cells were mainly macrophages and Schwann cells. Daily treatment with uric acid, a scavenger of peroxynitrite, decreased nitrotyrosine formation in the injured sciatic nerve, and produced concomitant alleviation of thermal hyperalgesia and Wallerian degeneration. These results provide the first evidence that peroxynitrite is formed after partial nerve injury, and contributes to the initiation of thermal hyperalgesia and Wallerian degeneration. We hypothesize that uric acid alleviates hyperalgesia and Wallerian degeneration by inhibiting oxidative damage caused by peroxynitrite and possibly also by decreasing the production of other inflammatory mediators such as prostaglandins.

Treatment as harm reduction, defunding as harm maximization: the case of methadone maintenance.

Despite numerous research studies demonstrating the efficacy of methadone maintenance treatment (MMT) in general and the value of retention in particular, the increasing defunding of this modality has compromised its potential. From 1990 to 1995 the lead author conducted a longitudinal research project to determine the impact of the cost of treatment on 233 San Francisco Bay Area study participants seeking, enrolled in, or defunded from MMT. This paper reports on selected findings from that study. Using variables of drug use, crime, gender and HIV risk, qualitative and quantitative results comparing those seeking treatment with those enrolled in treatment indicated that MMT functioned as a harm-reduction tool. When clients were defunded, however, drug use, crime and HIV risk increased and harm was maximized.

Phosphoenolpyruvate/adenosine triphosphate enhances post-ischemic survival of skeletal muscle.

This study examined whether ischemia-reperfusion injury to skeletal muscle could be reduced by post-ischemic infusion of phosphoenolpyruvate (PEP) and adenosine triphosphate (ATP). The rectus femoris muscle of 54 rabbits was rendered ischemic for 3.5 hr. Eighteen rabbits received no further treatment. Thirty-six were infused intra-arterially at the end of ischemia, 18 with vehicle alone, and 18 with a mixture of PEP (80 mumol/kg) and ATP (2.6 mumol/kg). Six rabbits from each group were explored after 24 hr reperfusion and the muscles assessed for viability (by nitro blue tetrazolium), ATP (by luciferin-luciferase chemiluminescence), malonyldialdehyde (MDA) (thiobarbituric acid method), and water content. The remaining muscles in each group were examined histologically after either 1 hr or 4 days of reperfusion. At 24 hr the viability of the PEP/ATP infused muscles (78.9 +/- 15.4 percent) was significantly greater than that of untreated (41.4 +/- 27.3 percent) or vehicle-infused groups (34.0 +/- 32.7 percent). ATP stores were significantly higher and MDA (indicative of free radical activity) and water content significantly lower in the PEP/ATP treated group. At 24 hr and 4 days, muscles infused with PEP/ATP showed less necrosis and fewer infiltrating neutrophils than the untreated groups. Studies with isolated rabbit neutrophils showed that ATP alone significantly inhibited superoxide anion production by stimulated neutrophils. However, when combined with PEP at concentrations similar to those achieved in vivo, ATP did not significantly affect superoxide production. The findings indicate that post-ischemic infusion of PEP/ATP significantly reduces ischemia-reperfusion injury in rabbit skeletal muscle. The protective effect of PEP/ATP is more likely to be due to supplementation of intracellular ATP stores than to the inhibition of superoxide production by infiltrating neutrophils.

Autologous lymphocyte therapy for experimental canine lymphoedema: a pilot study.

Obstructive lymphoedema, an accumulation of protein-rich fluid in interstitial spaces, was created in five dogs by a combination of the irradiation of one groin and subsequent surgical ablation of any remaining lymphatics. The lymphoedema was stable for up to 2 years. The aim was to test the efficacy of intra-arterial injection of autologous lymphocytes as a therapy for lymphoedema. The hypothesis was that cytokines produced by lymphocytes mediate proteolysis by macrophage proteinases in the lymphoedematous limb to remove the excess protein and relieve the oedema. A concentrated lymphocyte-rich preparation was isolated from blood by the Ficoll-Paque method. These preparations were injected into the femoral artery four times at approximately 4 weekly intervals. Three months after the first injection of lymphocytes, lymphoedematous limbs showed a marked 69% reduction in the mean excess circumferences compared with opposite control limbs. After treatment, skin thickness and hydroxyproline content (both measures of fibrosis) as well as water content (a measure of oedema) had reduced significantly. In specimens of interstitial fluid and in skin homogenates acidic proteinase activity increased and the protein concentration decreased significantly compared with controls. It is concluded that increased proteolysis, possibly due to activated macrophages recruited to the lymphoedematous limb, may partly explain these results.

Drug mixture which improves survival of ischemic rabbit epigastric skin flaps.

The chief aim of this study was to maximize flap survival by counteracting the pathophysiological changes occurring during ischemia-reperfusion. Rabbit epigastric skin flaps given 21 hours of ischemia were infused intra-arterially with selected drugs at the start of reperfusion. Compared with control infused ischemic flaps, which had a 33% survival rate on day 7 post-ischemia, significant improvement was found with vasodilators nitrendipine (61%) and prostacyclin (65%) and the thrombolytic agent urokinase (65%); marginal improvement with the free radical scavenger desferrioxamine (53%); but no change with streptokinase (44%), heparin (21%), and ATP-MgCl2 (35%). A drug mixture comprising all of these agents except streptokinase and urokinase produced 87% survival, suggesting an additive effect. Biochemical assays on skin homogenates and blood implicated oxygen free radicals, neutrophil infiltration, and thromboxane in flap failure. These results imply that multiple factors are responsible for ischemic flap failure and that a mixture of drugs needs to be infused to counteract all of the detrimental changes.

Calcium supplementation on normotensive and hypertensive pregnant women.

Normotensive and hypertensive pregnant women participated in a study to determine the effects of calcium supplementation on blood pressure. Subjects were randomly assigned to control or supplemented groups (1000 mg Ca/d). Blood pressure and serum total and ionic calcium were measured during the 20-wk supplementation period. Calcium supplementation had a significant lowering effect on diastolic blood pressure over the course of the study in the hypertensive group only. The hypertensive control subjects' mean serum ionic calcium value decreased significantly (P less than 0.05) over the course of the experiment. A significant (P less than 0.05) inverse relationship was observed between dietary calcium intake and blood pressure (r = -0.386 for systolic pressure and -0.359 for diastolic pressure).

Patellar location changes following EMG biofeedback or progressive resistive exercises.

Changes in the patellofemoral congruence (PFC) angle, the patellar rotation (PR) angle, and the sulcus angle following EMG biofeedback training that emphasized vastus medialis obliquus strengthening, the Daily Adjustable Progressive Resistive Exercise (DAPRE) technique, or no exercise were studied. Subjects were 30 normal, college females. The EMG biofeedback group and the DAPRE group followed established protocols for a 3-wk training period. The control group refrained from exercise. Patellar angles were determined with x-rays both pre- and posttest with the quadriceps relaxed and contracted. Reliability of the x-rays was determined with a correlation matrix of pre- and posttest sulcus angle measurements (P less than 0.001). EMG biofeedback training resulted in significant changes in the PFC angle with the quadriceps contracted (P less than 0.05). DAPRE resulted in significant changes in the PR angle with the quadriceps contracted (P less than 0.05). The results of this study suggest that quadriceps group strength changes are not enough to fully rehabilitate patellar tracking dysfunctions. The use of EMG biofeedback training to selectively strengthen the vastus medialis obliquus appears to be essential in correcting faulty patellar tracking.

Experience with calcium antagonists nitrendipine, diltiazem, and verapamil and beta 2-agonist salbutamol in salvaging ischemic skin flaps in rabbits.

This study investigated the efficacy of selected agents in the salvage of experimental skin flaps in rabbits after 21 hours of 25 degrees C ischemia. Calcium channel antagonists nitrendipine, diltiazem, and verapamil increased ischemic skin flap survival in rabbits from 33.3% for buffered saline infused controls to 71.4% (P less than 0.05), 71.4% (P less than 0.05), and 50.0% (not significant) respectively. The beta 2-adrenoceptor agonist salbutamol produced an increase in survival to 64.3%, which narrowly missed statistical significance. All four test agents invoked a vasodilatory response (greatest for nitrendipine, diltiazem, and salbutamol), a slight fall in blood pressure, and a small increase in heart rate. It is concluded that the vasodilatory response in the microcirculation of the ischemic flap helped to minimize the risk of occlusion due to thrombosis or cell sludging during reperfusion, thus leading to improved flap survival.

Gastric rupture and death caused by ipecac syrup.

We have reported a fatal complication of a therapeutic dose of ipecac syrup administered in a hospital emergency room. This child received 15 ml of ipecac syrup shortly after ingesting one to five tablets of chlorpheniramine maleate (4 mg). A prolonged course of vomiting (more than 24 hours) eventually resulted in gastric rupture and death. While the use of ipecac is both efficacious and safe in the overwhelming majority of cases, there have been documented fatalities after appropriate doses. For this reason, ongoing education for physicians is important; education of parents is also warranted since wide-scale distribution to families is the accepted standard. Because most patients stop vomiting within two to three hours after ipecac administration, we recommend that children with persistent vomiting should be observed in a medical facility, where electrolyte levels can be measured and fluids can be replaced if necessary.

Laboratory diagnosis and oral treatment of CAPD peritonitis.

The laboratory diagnosis of 50 consecutive episodes of peritonitis in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) was studied. The technique which yielded the highest rate (84%) of positive bacteriological diagnoses was inoculation and subculture of thioglycollate broth. Cloudiness of fluid to the naked eye was an accurate predictor of a raised white cell count. A minimum laboratory protocol for the bacteriological diagnosis of CAPD peritonitis was devised and has been in use satisfactorily since the completion of the study. Antibiotic treatment was given orally in the first instance in 43 episodes and was successful in 34.

Synchronous regulation of VH and CH allotypes among Ig molecules in multi-heterozygous rabbits suppressed with anti-VH allotype antibody: emergence of IgA from suppression prior to IgG and IgM.

Heterozygous rabbits of genotype a1n81f73g74/a2n82f71g75 were suppressed at birth for the VH region a1 allotype. At 8 weeks of age, quantitative analysis of serum IgG, IgM, and IgA molecules showed that the VHa1 specificity was effectively suppressed in the three classes of Ig and that the suppression was extended to the CH region n81 specificity on mu-chains as well as to the CH region f73 and g74 specificities on alphaf and alphag chains. At 26 weeks of age, analysis of serum IgG and IgM molecules showed that a1 was still suppressed to approximately the same extent in both Ig classes and the suppression was still extended to the CH region n81 specificity. However, at 26 weeks, the percentage of molecules with a1 specificity had doubled among serum and colostral IgA molecules and this increase was extended to the CH region f73 and g74 specificities. Thus, the suppressed allotypes reappeared first among IgA molecules. Our data are consistent with a regulatory mechanism which controls and synchronizes the expression of the VHa and the CH allotypes expressed on the same heavy chain. The order of the re-expression of the suppressed allotypes with respect to Ig class may allow further definition of selective regulatory mechanisms for the synthesis of Ig classes.

Distribution of covalently bound and non-covalently bound secretory component on sbuclasses of rabbit secretory IgA.

The distribution of non-covalently bound secretory component (SC) on the two subclasses, IgA-f and IgA-g of rabbit secretory IgA (sIgA) was determined; the two subclasses were separated from each other by the use of antibody-immunosorbent columns and were subjected to SDS polyacrylamide gel electrophoresis. No SC appeared to be dissociated from the IgA-f molecules from each of 11 different rabbits; the IgA-g molecules, however, did have SC which was dissociated by SDS. Thus, all of the noncovalently bound SC on rabbit sIgA resides on the IgA-g subclass molecules.