Rotational motion in liquid water is anisotropic: a nuclear magnetic resonance and molecular dynamics simulation study

Experimental NMR measurements of the deuterium and (17)O T(1) relaxation times in deuterium-enriched liquid water have been performed from 275 to 350 K. These relaxation times can yield rotational correlation times of appropriate molecule-fixed unit vectors if the quadrupole coupling constants and asymmetry parameters are known. We determine the latter from ab initio studies of water clusters and experimental chemical shift measurements. We find that the rotational correlation time for the OD bond vector in D(2)(16)O varies from 5.8 ps at 275 K to 0.86 ps at 350 K, and that the rotational correlation time for the out-of-plane vector of dilute D(2)(17)O in D(2)(16)O varies from 4.4 ps at 275 K to 0.64 ps at 350 K. These results indicate that the rotational motion of water is anisotropic. Molecular dynamics simulations of liquid water are in good agreement with these experiments at the higher temperatures, but the simulation results are considerably faster than experiment at the lower temperatures.

Multiple antibiotic changes during the first 72 hours of hospitalization

BACKGROUND

Increasing concern about inappropriate antibiotic use prompted us to examine whether our patients were receiving frequent and perhaps unwarranted changes of antibiotic therapy.

METHODS

We evaluated antibiotic prescribing by the physicians in the Emergency Department and by those on the inpatient medical service during the first 72 hours of hospitalization in 119 patients admitted with suspected serious infections to an acute care, university-affiliated, municipal teaching hospital. The appropriateness of antibiotic prescriptions was assessed independently and retrospectively by 2 infectious disease specialists (each based at a different hospital) using a 4-grade scale (from 1 = wrong choice to 4 = appropriate). Of their evaluations of the 427 antibiotic regimens given to the 119 patients during 4 defined intervals during their first 72 hours of hospitalization, 90% agreed with each other within 1 grade. Their evaluations were then compared with the selections that had been made at each interval by the prescribing physicians.

RESULTS

Successive prescribing physicians changed the antibiotic regimens in 77% of cases during the first 24 hours and in 56% during the next 48, often without apparent clinical or microbiologic indications. By 72 hours, the 119 patients had received a mean of 3.1 +/- 1.3 (+/-SD) different antibiotics, and 40 received between 4 and 7. Only 7% of the patients had no change in the regimen prescribed originally.

CONCLUSIONS

Many patients had multiple changes of antibiotics, often unnecessarily, resulting in exposure to too many agents.

Dietary intake of elite figure skating dancers

The main objective of the present study was to examine the dietary intake and physiological status of members of the US National Figure Skating Dance Team. Study participants included seven female and seven male figure skating dance pairs. Three-day food records were collected from each dancer and analyzed using a computerized nutrient database. Height, body weight and skinfold measurements were completed on each dancer. Body fat was estimated using the Jackson et al prediction equations. Fasting blood samples were collected for biochemical analysis. Total energy intake of female dancers (1416 kcal/d, 339 kjoules/day) was considerably lower than the dietary recommendations, while the male dancers appeared to have adequate energy intake (2837 kcal/d, 679 kjoules/day). Carbohydrate intake of both male and female dancers was below the recommendations, 44% and 51%, respectively, whereas total fat and protein intake of both male and female dancers were higher than the dietary recommendations. All dancers met at least 2/3(rd) of the dietary recommendations for all micro-nutrients, except folate and zinc intake of the female dancers, which were 68% and 62% of the recommended values. Although, blood lipid concentrations and other physiological parameters of the overall group were within normal ranges, two of the dancers (14% of the dancers) had elevated blood cholesterol concentrations and low iron status. The results of the present study suggest that these elite figure skating dancers, especially females, may not be consuming adequate amounts of energy-yielding nutrients and those that influence bone health. Future studies are needed to examine the effects of nutritional status on performance of these figure skating dancers and to develop strategies to improve the nutritional status of these elite dancers.

Ganglion of the distal interphalangeal joint (myxoid cyst): therapy by identification and repair of the leak of joint fluid

BACKGROUND

Digital myxoid cysts are a relatively common pathology in the skin, representing a ganglion of the adjacent distal interphalangeal joint. Success of treatment is largely proportional to the destructiveness of the therapy and postoperative morbidity. We studied an effective, minimally traumatic surgical treatment in which tissue is not removed and morbidity is low.

DESIGN

Open, nonrandomized trial of therapy. Methylene blue dye was injected into the distal interphalangeal joint. A skin flap was designed around the cyst and raised to identify the dye-filled communication between joint and cyst. The communication was sutured and the flap was replaced with no tissue excision.

SETTING

Two university dermatology departments.

PATIENTS

Fifty-four subjects with 47 cysts involving fingers or thumbs and 7 involving toes. Previous therapies in 37 patients had resulted in relapse.

MAIN OUTCOME MEASURES

Clinical assessment at 2 and 8 months.

RESULTS

We treated 34 women and 20 men (mean age, 60.4 years; range, 45-83 years). Communication between cyst and joint was identified by means of methylene blue injection in 48 patients (89%). At 8 months, 48 patients remained cured with no visible scarring. Of these, nail dystrophy associated with the cyst preoperatively (n = 35) resolved in all but 1 patient (97%). Six patients had relapses (5 within 4 months). Of these, 3 were on the toes. Cure rate on toes was 4 of 7 (57%) and on fingers, 44 of 47 (94%). In 2 patients, pain persisted for 4 months and then resolved. Limitation of joint mobility resolved after 2 months in 1 subject.

CONCLUSIONS

Ligature of myxoid cyst origin at the joint capsule is an effective treatment and does not require excision. Myxoid cysts on toes are more likely to relapse than those on fingers.

Coronary vasomotor and cardiac electrophysiologic effects of diadenosine polyphosphates and nonhydrolyzable analogs in the guinea pig

Platelet activation in heart disease is important owing to the effects of platelet-derived compounds on myocardial perfusion and cardiac electrophysiology. Diadenosine polyphosphates are secreted from platelets and present in the myocardium, but their electrophysiologic and vasomotor effects are incompletely understood. We used isolated guinea-pig hearts to study the effects of diadenosine triphosphate (Ap3A), tetraphosphate (Ap4A), pentaphosphate (Ap5A), and hexaphosphate (Ap6A) (10 pM-0.1 mM), comparing their actions to those of adenosine, adenosine triphosphate, and non-hydrolyzable Ap4A and Ap5A analogs. Diadenosine polyphosphates (0.1 nM-0.1 microM) transiently reduced coronary perfusion pressure, which recovered during the continued presence of the compounds. At concentrations greater than 0.1 microM effects were maximal and sustained (perfusion pressure decreased from 36.5+/-3.4 to 18.6+/-2.5 mm Hg, p < 0.001, with 1 microM Ap4A). The changes in action potential duration and refractory period developed slowly but were maintained (0.1 nM-1 microM). With 1 nM Ap4A, action potential duration increased from 170.6+/-2.6 to 187.3+/-3.8 ms, p < 0.05, and refractory period increased from 138.5+/-1.6 to 147.9+/-2.0 ms, p < 0.05. Ap4A and its analog reduced QRS duration (from 24.7+/-1.1 to 13.9+/-1.6 ms with 1 microM Ap4A, p < 0.05). P2-purinergic (adenosine triphosphate) receptor antagonism (suramin) reduced perfusion pressure but was without electrophysiologic effect. Other changes in coronary perfusion pressure and electrophysiologic variables associated with Ap4A were not seen in the presence of suramin. P1-(adenosine) antagonism (8-[p-sulfophenyl]theophylline) attenuated the electrophysiologic effects only. Diadenosine polyphosphates have potent cardiac electrophysiologic and coronary vasomotor effects via purinergic receptors, suggesting an important role during platelet activation in acute coronary syndromes.

Progressive cardiac conduction defect and cardiomyopathy in siblings with syncope

Three siblings evaluated for syncope were found to have left bundle-branch block. Progression to complete heart block occurred in all. Pacemaker implantation eliminated syncopal epidoses in each case. Echocardiographic manifestations of cardiomyopathy were present in each child despite normal roentgenographic heart size. Careful family study identified no other affected members with conduction defects. These children area believed to represent a form of familial cardiomyopathy in which clinical manifestations of cardiac conduction system disease predominate.

Sculpted-multilayer optical effects in two species of Papilio butterfly

The wing-scale microstructures associated with two species of Papilio butterfly are described and characterized. Despite close similarities in their structures, they do not exhibit analogous optical effects. With Papilio palinurus, deep modulations in its multilayering create bicolor reflectivity with strong polarization effects, and this leads to additive color mixing in certain visual systems. In contrast to this, Papilio ulysses features shallow multilayer modulation that produces monocolor reflectivity without significant polarization effects.

Second generation knockout sickle mice: the effect of HbF

Sickle transgenic mice expressing exclusively human globins are desirable for studying pathophysiology and testing gene therapy strategies, but they must have significant pathology and show evidence of amelioration by antisickling hemoglobins. Mice were generated that expressed exclusively human sickle hemoglobin with 3 levels of HbF using their previously described sickle constructs (cointegrated human miniLCRalpha2 and miniLCRbeta(S) [PNAS 89:12150, 1992]), mouse alpha- and beta-globin-knockouts, and 3 different human gamma-transgenes. It was found that, at all 3 levels of HbF expression, these mice have balanced chain synthesis, nearly normal mean corpuscular hemoglobin, and, in some cases, F cells. Mice with the least adult HbF expression were the most severe. Progressive increase in HbF from less than 3% to 20% to 40% correlated with progressive increase in hematocrit (22% to 34% to 40%) and progressive decrease in reticulocyte count (from 60% to 30% to 13%). Urine concentrating ability was normalized at high HbF, and tissue damage detected by histopathology and organ weight were ameliorated by increased HbF. The gamma-transgene that produces intermediate levels of HbF was introduced into knockout sickle mice described by Pàszty and coworkers that express the miniLCRalpha1(G)gamma(A)gammadeltabeta(S) transgene and have fetal but not adult expression of HbF. It was found that the level of HbF required to ameliorate low hematocrit and normalize urine concentrating defect was different for the miniLCRalpha2beta(S) and miniLCRalpha1(G)gamma(A)gammadeltabeta(S) mice. We conclude that knockout mice with the miniLCRalpha2beta(S) transgene and postnatal expression of HbF have sufficiently faithful sickle pathology to serve as a platform for testing antisickling interventions.

Sex-related difference in amygdala activity during emotionally influenced memory storage

We tested the possibility suggested by previous imaging studies that amygdala participation in the storage of emotionally influenced memory is differentially lateralized in men and women. Male and female subjects received two PET scans for regional cerebral glucose-one while viewing a series of emotionally provocative (negative) films, and a second while viewing a series of matched, but emotionally more neutral, films. Consistent with suggestions from several previously published studies, enhanced activity of the right, but not the left, amygdala in men was related to enhanced memory for the emotional films. Conversely, enhanced activity of the left, but not the right, amygdala in women was related to enhanced memory for the emotional films. These results demonstrate a clear gender-related lateralization of amygdala involvement in emotionally influenced memory, and indicate that theories of the neurobiology of emotionally influenced memory must begin to account for the influence of gender.

Antibody to transforming growth factor-beta ameliorates tubular apoptosis in unilateral ureteral obstruction

BACKGROUND

Unilateral ureteral obstruction (UUO) is characterized by progressive renal atrophy, renal interstitial fibrosis, an increase in renal transforming growth factor-beta (TGF-beta), and renal tubular apoptosis. The present study was undertaken to determine the effect of a monoclonal antibody to TGF-beta (1D11) in UUO.

METHODS

Mechanical stretch was applied to tubular epithelial cells (NRK-52E) by a computer-assisted system. Three doses of 1D11 (either 0.5, 2, or 4 mg/rat) were administered to rats one day prior to UUO and every two days thereafter, and kidneys were harvested at day 13. Fibrosis was assessed by measuring tissue hydroxyproline and mRNA for collagen and fibronectin. Apoptosis was assessed with the terminal deoxy transferase uridine triphosphate nick end-labeling assay. TGF-beta levels were determined by bioassay. Western blot and immunostaining were used to identify proliferating cell nuclear antigen (PCNA), p53, bcl-2, and inducible nitric oxide synthase (iNOS).

RESULTS

Stretch significantly induced apoptosis in NRK-52E cells, which was accompanied by an increased release of TGF-beta; 1D11 (10 microg/mL) totally inhibited stretch-induced apoptosis. Control obstructed kidney contained 20-fold higher TGF-beta as compared with its unobstructed kidney; 1D11 neutralized tissue TGF-beta of the obstructed kidney. Control obstructed kidney exhibited significantly more fibrosis and tubular apoptosis than its unobstructed counterpart, which was blunted by 1D11. In contrast, 1D11 significantly increased tubular proliferation. p53 immunostaining was localized to renal tubular nuclei of control obstructed kidney and was diminished by 1D11. In contrast, bcl-2 was up-regulated in the 1D11-treated obstructed kidney. Total NOS activity and iNOS activity of the obstructed kidney were increased by 1D11 treatment.

CONCLUSION

The present study strongly suggests that an antibody to TGF-beta is a promising agent to prevent renal tubular fibrosis and apoptosis in UUO.

Effects of mild night chilling on respiration of expanding cotton leaves

Utilizing expanding leaves of cotton (Gossypium hirsutum L. cv. Coker 312), the hypothesis that suboptimal night temperatures above those for putative phase transitions of mitochondrial lipids caused greater substrate control of night respiration and increased the control that respiration exerted on ATP-dependent metabolism was tested. Night respiratory CO(2) evolution rates for 5-7-day-old leaves growing at 30/19 degrees (day/night) nearly equaled those of leaves exposed to 28 degrees C nights, while leaves exposed to 15 degrees C nights had rates that were 42% of those at 28 degrees C. No restriction of respiration by carbohydrate supply was detected for leaves grown at either cool night temperature or when warm-grown plants were transferred to cool night conditions. Pyruvate utilization was more sensitive to mild chilling than glycolysis. Growth at 30/19 or 30/15 degrees C resulted in higher nocturnal ATP:ADP and energy charge for expanding leaves than growth at 30/28 degrees C, suggesting a lessening of respiratory control of ATP-dependent metabolism with long-term night chilling. However, cool night exposure resulted in reductions in total phosphorylated adenylates, and the low ATP content, most notably occurring during 15 degrees C nights, may have restricted some metabolic activity. The cause of these low ATP levels and their possible effects on cotton metabolism during chilling remain to be elucidated.

Hemoglobin C in transgenic mice: effect of HbC expression from founders to full mouse globin knockouts

When present in the homozygous form, hemoglobin C (HbC, CC disease) increases red cell density, a feature that is the major factor underlying the pathology in patients with SC disease (Fabry et al., JCI 70, 1315, 1982). The basis for the increased red cell density has not yet been fully defined. We have generated a HbC mouse in which the most successful founder expresses 56% human alpha and 34% human beta(C). We introduced knockouts (KO) of mouse alpha- and beta-globins in various combinations. In contrast to many KO mice, all partial KOs have normal MCH. Full KOs that express exclusively HbC and no mouse globins have minimally reduced MCH (13. 7 +/- 0.3 pg/cell vs 14.5 +/- 1.0 for C57BL/6) and a ratio of beta- to alpha-globin chains of 0.88 determined by chain synthesis; hence, these mice are not thalassemic. Mice with beta(C) > 30% have increased MCHC, dense reticulocytes, and increased K:Cl cotransport. Red cell morphology studied by SEM is strikingly similar to that of human CC cells with bizarre folded cells. We conclude that red cells of these mice have many properties that closely parallel the pathology of human disease in which HbC is the major determinant of pathogenesis. These studies also establish the existence of the interactions with other gene products that are necessary for pleiotropic effects (red cell dehydration, elevated K:Cl cotransport, morphological changes) that are also present in these transgenic mice, validating their usefulness in the analysis of pathophysiological events induced by HbC in red cells.

Associations between primary appraisals and life-events while controlling for depression

OBJECTIVES

The main objective of this paper was to explore the associations between life-events and primary appraisals (threat, challenge and loss) controlling for depression. It was predicted that specific associations between life-events and primary appraisals would remain once depression had been partialled. A subgoal of this paper was to develop a content analytic coding frame for student life-events.

DESIGN

This study was a retrospective survey in which participants provided accounts of recent stressful encounters, and completed indices of primary appraisals and depression.

METHOD

The participants were 979 undergraduates who provided descriptions of life-events. A subsample of 391 provided additional information on primary appraisals and depression. The primary outcomes were the partial correlations between life-events and primary appraisals.

RESULTS

There were significant associations between life-events and primary appraisals above and beyond variance explained by depression. Results also indicated that the definition of loss appraisals could be extended to include events that were related to anticipated future loss, especially if the event was also perceived as threatening. Also certain self-defined negative life-events were appraised as positive. Life-events were shown to vary systematically as a function of external constraints (e.g. stage of the academic year).

CONCLUSIONS

A variety of events were associated with loss appraisals and this may have implications for risk factors in depression.

Myocarditis and cardiomyopathy associated with clozapine

BACKGROUND

Clozapine is effective for resistant schizophrenia. After two sudden deaths in physically well young men soon after starting clozapine, we investigated the cardiovascular complications for this drug.

METHODS

From January, 1993, to March, 1999, 8000 patients started clozapine treatment in Australia, and were registered with a mandatory monitoring service. We identified cases of myocarditis and cardiomyopathy from voluntary reports to the Australian Adverse Drug Reaction Committee and sought details of the relevant diagnostic studies, necropsies that had been done in suspicious cases, or both.

FINDINGS

23 cases (20 men, three women, mean age 36 years [SD 9]) were identified: 15 of myocarditis and eight of cardiomyopathy associated with clozapine treatment. Six patients died. All cases of myocarditis (five deaths) occurred within 3 weeks of starting clozapine. Cardiomyopathy (one death) was diagnosed up to 36 months after clozapine was started. Necropsy results showed mainly eosinophilic infiltrates with myocytolysis, consistent with an acute drug reaction.

INTERPRETATION

Clozapine therapy may be associated with potentially fatal myocarditis and cardiomyopathy in physically healthy young adults with schizophrenia.

A tale of two sciences: bedside and bench in twentieth-century Britain

Images

Single clonal origin of a high proportion of Legionella pneumophila serogroup 1 isolates from patients and the environment in the area of Paris, France, over a 10-year period

Arbitrarily primed PCR with three primers and pulsed-field gel electrophoresis were used to characterize a set of 75 clinical Legionella pneumophila serogroup 1 isolates, with no apparent epidemiological link, obtained from 24 hospitals in Paris, France, from 1987 to 1997. Unexpectedly, 25 clinical isolates from 15 hospitals had an identical profile (termed type A) by both methods. The same profile was subsequently found in 16 of 64 randomly selected environmental L. pneumophila serogroup 1 isolates from 15 different sites in the Paris area. There was no evidence of geographic clustering or a peak incidence of type A isolation. Type A has not been found in France outside the Paris area, suggesting that a particular type of L. pneumophila serogroup 1 is specifically present in the Paris water distribution network.

The effects of income inequality on health

Much of the discussion about individual and group differences in illness and life expectancy has focused on the effects of individual characteristics, both status and behavioural. This is also characteristic of much of the literature, which attempts to explain why men have higher rates of disease and lower life expectancy than women. After a period in which 'social policy was no longer such an important part of preventive health policy', there is now renewed interest in the influence of the socioeconomic environment on health. Indeed, recently compiled evidence indicates that increasing income inequality is likely to have adverse effects on the community's health. These findings highlight the potential dangers of policy changes which accelerate social and economic divisions.

System memory in violent incidents: evidence from patterns of reoccurrence

For 20% of a sample of 1,078 violent incidents reported in British bars and pubs, another incident was reported at the same premises within 6 months. Log-survival analysis revealed nonrandom sequences that demonstrate a system memory effect separate from any biases involving particular venues. The rate of reoccurrence was not constant during the 6 months following incidents but was significantly higher for Weeks 1-4, approximated to the mean value for Weeks 5-12, and declined for Weeks 13-26. Reoccurrence was particularly likely in the first 3-4 days after an incident. Risk of reoccurrence was further increased for incidents that involved either threats or the exit and return of the assailants within that original incident. Results support the view that "violence breeds violence" and demonstrate the need for increased staff vigilance for up to 12 weeks following a violent incident, and particularly during the first few days and weeks.

The valve of Vieussens: an important cause of difficulty in advancing catheters into the cardiac veins

INTRODUCTION

The coronary sinus and cardiac veins are useful conduits for the passage of electrode catheters for mapping the origin of cardiac arrhythmias. However, sometimes it is difficult to advance catheters an adequate distance into the cardiac veins. The aim of this study was to determine the reasons for this.

METHODS AND RESULTS

In 50 cadaveric hearts, a deflectable 7-French electrode catheter was passed from the right atrium into the coronary sinus and advanced to the anterior interventricular portion of the great cardiac vein (GCV). Causes of obstruction were determined. The catheter was obstructed by the valve of Vieussens in 23 of 50 hearts (46%). Once the valve was negotiated, obstruction was caused by an acute bend in the GCV in 28 of 50 hearts (56%). Clinical studies were undertaken in 10 patients in whom electrode catheters could not be advanced as far as required. Using contrast venography, the most frequent cause of obstruction was determined to be the valve of Vieussens in 8 of 10 cases (80%). An acute bend in the GCV caused obstruction in 2 cases (20%).

CONCLUSIONS

The valve of Vieussens is a frequent cause of obstruction to passage of a catheter in postmortem and in vivo studies. An acute bend in the vein, with or without lodgment in a tributary, is the other common cause. In adults, venous luminal diameter is not a cause of obstruction to the passage of a 7-French catheter in the coronary sinus or proximal GCV.

A Na+-activated K+ current (IK,Na) is present in guinea-pig but not rat ventricular myocytes

The effects of removing extracellular Ca2+ and Mg2+ on the membrane potential, membrane current and intracellular Na+ activity (aiNa) were investigated in guinea-pig and rat ventricular myocytes. Membrane potential was recorded with a patch pipette and whole-cell membrane currents using a single-electrode voltage clamp. Both guinea-pig and rat cells depolarize when the bathing Ca2+ and Mg2+ are removed and the steady-state aiNa increases rapidly from a resting value of 6.4+/- 0.6 mM to 33+/-3.8 mM in guinea-pig (n=9) and from 8.9+/-0.8 mM to 29.3+/-3.0 mM (n=5) in rat ventricular myocytes. Guinea-pig myocytes partially repolarized when, in addition to removal of the bathing Ca2+ and Mg2+, K+ was also removed, however rat cells remained depolarized. A large diltiazem-sensitive inward current was recorded in guinea-pig and rat myocytes, voltage-clamped at -20 mV, when the bathing divalent cations were removed. When the bathing K+ was removed after Ca2+ and Mg2+ depletion, a large outward K+ current developed in guinea-pig, but not in rat myocytes. This current had a reversal potential of -80+/-0.7 mV and was not inhibited by high Mg2+ or glybenclamide indicating that it is not due to activation of non-selective cation or adenosine triphosphate (ATP)-sensitive K channels. The current was not activated when Li+ replaced the bathing Na+ and was blocked by R-56865, suggesting that it was due to the activation of KNa channels.

Diffuse axonal injury in a rugby player

Sections of the cerebrum, cerebellum, and brain stem of a rugby player who died 15 hours after being tackled were stained using an immunoperoxidase technique to detect beta-amyloid protein. The sections of the pons showed axonal spheroids in the base, and those of the cerebellum showed axonal spheroids in deep white matter. The findings demonstrated axonal injury following a fall from the victim's height in a team sporting event.

Plasmodium falciparum: enhanced gametocyte formation in vitro in reticulocyte-rich blood

Concentrates of late stage parasites of the gametocyte-forming clone HB-3 were mixed with blood rich in reticulocytes from anemic patients, or with normal control blood, and kept under culture conditions for 4 days. Significantly more gametocytes were always formed in the reticulocyte-rich blood than in the control. This was true whether the anemic blood supported a larger asexual parasitemia than the control, or a lower one, or the same and without regard to the cause of the anemia. Gametocytes as a percentage of asexual forms were up to 10 times higher in reticulocyte-rich blood than in normal blood.

Is there a rationale for rationing chronic dialysis? A hospital based cohort study of factors affecting survival and morbidity

OBJECTIVES

To determine factors influencing survival and need for hospitalisation in patients needing dialysis, and to define the potential basis for rationing access to renal replacement therapy.

DESIGN

Hospital based cohort study of all patients starting dialysis over a 4 year recruitment period (follow up 15-63 months). Groups were defined on the basis of age, comorbidity, functional status, and whether dialysis initiation was planned or unplanned.

SETTING

Renal unit in a district general hospital, which acts as the main renal referral centre for four other such hospitals and serves a population of about 1.15 million people.

SUBJECTS

292 patients, mean age 61.3 years (18-92 years, SD 15.8), of whom 193 (66%) were male, and 59 (20%) were patients with diabetes. Dialysis initiation was planned in 163 (56%) patients and unplanned in 129 (44%).

MAIN OUTCOME MEASURES

Overall survival, 1 year survival, and hospitalisation rate.

RESULTS

Factors affecting survival in the Cox's proportional hazard model were Karnofsky performance score at presentation (hazard ratio 0.979, 95% confidence interval 0.972 to 0. 986), comorbidity severity score (1.240, 1.131 to 1.340), age (1.036, 1.018 to 1.054), and myeloma (2.15, 1.140 to 4.042). The Karnofsky performance score used 3 months before presentation was significant (0.970, 0.956 to 0.981), as was unplanned presentation in this model (1.796, 1.233 to 2.617). Using these factors, a high risk group of 26 patients was defined, with 19.2% 1 year survival. Denying dialysis to this group would save 3.2% of the total cost of the chronic programme but would sacrifice five long term survivors. Less rigorous definition of the high risk group would save more money but lose more long term survivors.

CONCLUSIONS

Severity of comorbid conditions and functional capacity are more important than age in predicting survival and morbidity of patients on dialysis. Late referral for dialysis affects survival adversely. Denial of dialysis to patients in an extremely high risk group, defined by a new stratification based on logistic regression, would be of debatable benefit.

Reproduction and Captive Breeding as a Tool for Mammal Conservation: The Role of Modem Zoos

There is a growing awareness in the scientific research community of the role that zoological institutions can play in the conservation of threatened or endangered species. Zoos themselves have changed and become more focussed on the contributions they can make to regional conservation objectives, driven in part by the "World Zoo Conservation Strategy" published in 1993. Perth Zoo has committed itself to this strategy and established a collaborative scientific research program with Conservation and Land Management (CALM), WA, to develop captive breeding techniques for a number of Western Australian native species. To achieve this objective, the zoo has established a sub-program known as the Native Species Breeding Program. This consists of 6 specialist keepers who are charged with developing specialised skills in captive husbandry of selected species, and the implementation of research projects. All of the species under study are part of recovery plans, and many of the species are being produced for release under the objectives of those plans and as part of CALM&apos;s "Western Shield Project". Mammal species under study are the Numbat, Chuditch, Dibbler, Djoongari (Shark Bay Mouse) and the Wopilkara (Greater Stick Nest Rat). Currently, Chuditch, Numbats and Djoongari bred in captivity have been the subject of re-introduction programs. The results of these breeding programs and the subsequent releases of selected species into different habitats in Western Australia will be presented, along with a discussion of the issues which relate to the limitations of captive breeding as a conservation tool.

Production of interleukin-12 by murine macrophages in response to bacterial peptidoglycan

Peptidoglycan (PG), a component of the bacterial cell wall, has various immunomodulating activities, including the capacity to induce delayed-type hypersensitivity reactions to antigens administered in Freund's adjuvant. We report that PG induces interleukin-12 (IL-12) mRNA production and IL-12 secretion by mouse macrophages. The capacity of PG to induce IL-12 production, like its previously reported immunomodulating activities, was dependent on the structure of its peptide subunit. PG from Bacillus megaterium and Staphylococcus aureus induced IL-12 production, whereas PG from Micrococcus luteus and Corynebacterium poinsettiae did not. The ability of most bacterial PGs to induce IL-12 production suggests that they play an important role in triggering host defense mechanisms against bacterial infections.

Essential skills for paediatric nurses

Concerns about the varied nature of practical learning, experiences available to students prompted this study of the skills required to nurse children. Experienced paediatric nurses were surveyed to identify which skills they considered to be essential and which desirable in child branch diplomates. Out of 74 practical skills. 47 were believed to be essential on qualification. This list of skills could provide an expected baseline for students to achieve during their educational programme.

[Comparative activity of cefepime, ceftazidime and imipenem in a mouse infection caused by Klebsiella pneumoniae producing a broad spectrum beta-lactamase]

Mice experimentally infected with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae strains were injected twice daily for three days with ceftazidime, cefepime, or imipenem (25, 50, or 100 mg/kg/injection). Treatment efficacy was based on five-day survival and on the spleen viable bacteria count 16 hours after the last treatment dose. Under these experimental conditions, ceftazidime showed some activity on strains with low levels of resistance to ceftazidime. Cefepime used in a dose of 50 or 100 mg per injection demonstrated good activity but was slightly less effective than imipenem.

Expression of feline recombinant interferon-gamma in baculovirus and demonstration of biological activity

We have previously reported the cloning of the coding sequence for feline-specific interferon-gamma. Here, we describe the expression of this sequence in a baculovirus system and demonstrate the biological activity of the recombinant protein. The coding sequence for feline interferon was directionally cloned into the baculovirus transfer vector pAcCL29-1. Transfer vector and linearized wild-type AcMNPV (BacPAK6) were used to co-transfect Sf9 cells by calcium phosphate coprecipitation. Subsequently, wild-type and recombinant viruses were separated by plaque assay. Recombinant plaques were expanded and a master stock of virus is produced. Production of biologically active interferon-gamma from infected Sf9 cells was demonstrated using a standard cytopathic effect reduction assay, utilising vesicular stomatitis virus (VSV), and an MHC class II induction assay.

Temporal architecture of violent incidents

Five hundred five reports of violent incidents in British pubs and bars were studied by using logical pathway modeling to provide information on the processes underlying work-related violence. Logical pathway modeling is innovative in examining and mapping sequences in real incidents at a population level. The data reveal the most common pathway to be misbehavior by customers, intervention by staff (before any physically violent act), physical attack on staff, and injury to staff. The data also highlight the likelihood of further action after assailants have exited and identify stages in incidents at which most staff and customer injuries and damage to property occur. Results assist in the design of strategies to reduce the risk from future violence, particularly by training staff to recognize and to handle potentially violent situations and to maintain vigilance and security following problem incidents.

Placement of cardiac electrodes: written, simulated, and actual accuracy

BACKGROUND

Research has shown that critical care nurses show low accuracy on written tests of placement of electrodes, yet it is unknown how this low accuracy translates into placement of electrodes on actual patients.

OBJECTIVES

To determine if accuracy scores differ between three methods (written knowledge, simulated clinical practice, actual clinical practice) of evaluating placement of continuous ECG electrodes by a group of cardiac care nurses.

METHODS

A standardized scoring diagram was used with three different methods of measuring the accuracy of 44 nurses who worked on a telemetry unit or medical ICU in placing continuous ECG electrodes. The three methods were (1) written knowledge--placement of stickers on a diagram of a torso, (2) simulated clinical practice--placement of electrodes on a human model, and (3) actual clinical practice--placement of electrodes on an assigned patient.

RESULTS

For the total diagram score (maximum score = 11), no significant differences among groups were found. For the V1 subscale score (maximum score = 4), a significant difference among groups was found: Scheffé's test showed that the significant difference was between simulated and actual clinical practice. Percentages of nurses achieving the maximum, or accurate, score were 18% for written knowledge, 25% for simulated clinical practice, and 9% for actual clinical practice.

CONCLUSIONS

Although total scores did not differ among groups, the mean scores indicate that placement of electrodes was not accurate by any method. This finding has implications for how electrode placement is taught to nurses and for the accountability of nurses for placement of electrodes on their patients.

Placement of cardiac electrodes: written, simulated, and actual accuracy

BACKGROUND: Research has shown that critical care nurses show low accuracy on written tests of placement of electrodes, yet it is unknown how this low accuracy translates into placement of electrodes on actual patients. OBJECTIVES: To determine if accuracy scores differ between three methods (written knowledge, simulated clinical practice, actual clinical practice) of evaluating placement of continuous ECG electrodes by a group of cardiac care nurses. METHODS: A standardized scoring diagram was used with three different methods of measuring the accuracy of 44 nurses who worked on a telemetry unit or medical ICU in placing continuous ECG electrodes. The three methods were (1) written knowledge--placement of stickers on a diagram of a torso, (2) simulated clinical practice--placement of electrodes on a human model, and (3) actual clinical practice--placement of electrodes on an assigned patient. RESULTS: For the total diagram score (maximum score = 11), no significant differences among groups were found. For the V1 subscale score (maximum score = 4), a significant difference among groups was found: Scheffe's test showed that the significant difference was between simulated and actual clinical practice. Percentages of nurses achieving the maximum, or accurate, score were 18% for written knowledge, 25% for simulated clinical practice, and 9% for actual clinical practice. CONCLUSIONS: Although total scores did not differ among groups, the mean scores indicate that placement of electrodes was not accurate by any method. This finding has implications for how electrode placement is taught to nurses and for the accountability of nurses for placement of electrodes on their patients.

Non-mutagenic repair of (6-4)photoproducts by (6-4)photolyase purified from Drosophila melanogaster

The (6-4)photoproduct DNA photolyase ((6-4)photolyase) repairs UV-induced pyrimidine (6-4) pyrimidone photoproduct ((6-4)photoproduct, pyr[6,4]pyr) in a light dependent manner. Drosophila (6-4)photolyase was purified to near homogeneity from Drosophila embryonic cells and is shown to be a 62 kDa protein as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified (6-4)photolyase repairs (6-4)photoproducts induced at 5'-CC-3' site (C[6,4]C) as well as T[6,4]T and T[6,4]C. Photoreactivation of (6-4)photoproduct constructed in M13 phage eliminates the replication block and abolishes induced mutagenesis in E. coli cells, suggesting that the (6-4)photolyase repairs the photoproduct to the unmodified form.

Bayesian adaptive alignment and inference

Sequence alignment without the specification of gap penalties or a scoring matrix is attained by using Bayesian inference and a recursive algorithm. This procedure's recursive algorithm sums over all possible alignments on the forward step to obtain normalizing constants essential to Bayesian inferences, and samples from the exact posterior distribution on the backward step. Since both terminal and intervening unrelated subsequences will often be excluded from an alignment, the resulting alignments may be seen as extensions of local alignments. An alignment's significance is assessed using the Bayesian evidence. A shuffling simulation shows that Bayesian evidence against the null hypothesis tends to be a conservative measure of significance compared to classical p-values. An application to proteins from the GTPase superfamily shows that the posterior distribution of the number of gaps is often flat and that the posterior distribution of the evolutionary distance is often flat and sometimes bimodal. An alignment of 1GIA with 1ETU shows good correspondence with a structural alignment.