Tailoring a hybrid three-component photoinitiating system for 3D printing

In the field of additive manufacturing DLP vat technologies are promising 3D printing techniques. The need of highly efficient photoiniating systems drives us to the development of photocyclic 3-component initiators. In order to improve the 3D printing sensitivity, we present in this paper the use of synthesized clay to tune up the photochemistry underlying the initiating radical production. Therefore, a three-component initiating system, based on a cationic dye, two coinitiators and with a clay filler suitable for DLP 3D printing of acrylate resins leading to high quality of parts and low printing time, is developed.

Development of a context-sensitive physical activity intervention for persons living with HIV and AIDS of low socioeconomic status using the behaviour change wheel

Background

Regular physical activity (PA) has been recommended for the management of HIV and AIDS. The purpose of this study was to develop a contextualised intervention for promoting PA among women living with HIV and AIDS (WLWHA) of low socioeconomic status (SES). A secondary aim of the study was to optimise the PA intervention using behavioural theory/ frameworks derived from preliminary studies and the literature.

Methods

The Behaviour Change Wheel (BCW) for designing behaviour change interventions was used. This method was further supplemented by evidence from the literature, systematic literature review (SLR), a concurrent mixed methods study and two cross-sectional studies. The SLR aided in determining the theoretical frameworks to inform the intervention, the specific PA behaviours to be targeted by the intervention, the intervention functions, the intervention policy category and the mode of delivery of the intervention. The concurrent mixed methods study was used to identify key factors that needed to change in order for participants to engage in regular PA. The first cross-sectional study was used to determine the gender to be targeted by the study. The second cross-sectional study was used to determine the domain and intensity of PA to target in the intervention.

Results

A face-to-face context-sensitive PA intervention employing 14 behavioural change techniques was designed. The PA intervention (a) utilised the Transtheoretical model of behaviour change and the Social Cognitive theory as the underpinning theoretical frameworks (b) included convenient PAs, such as walking, doing simple home-based exercises, engaging in activities of daily living or doing simple exercises at the community centre (c) used education, reward, training in PA, modelling exercise activities and enablement to increase the opportunity to engage in PA as intervention functions (d) used service provision as policy priorities, and (e) used a direct face-to-face mode of delivery.

Conclusions

The PA intervention emphasises behavioural techniques for increasing PA participation, such as goal-setting, self-monitoring, strategies for overcoming PA barriers, social support and rewards. The intervention employs strategies that highlight low-cost local PA resources and opportunities to help HIV infected women of low SES to participate in PA. The BCW provides a useful and comprehensive framework for the development of evidence and theory-based PA interventions for PLWHA of low SES. The BCW can thus be used in the development of interventions that ‘talk’ to policy by bridging the health inequality gap.

Physical activity behaviours of persons living with HIV of low socioeconomic status: domain, intensity and sociodemographic correlates

Physical activity (PA) is healthy for People Living with HIV and AIDS (PLWHA). This study examined the PA profile of 978 PLWHA based on PA domains and PA intensity. The study also sought to determine whether employment status and level of education can predict PA among PLWHA of low SES. PA and sociodemographic data of 978 PLWHA of mean age 35 (8.77) years were collected using the global physical activity questionnaire and a sociodemographic questionnaire. Results showed that, participants engaged more in work-related PA [160.11 (346.95) min/wk], followed by transport related PA [115.21(SD = 142.04) min/wk], and lastly in leisure related PA [40.84 (SD = 110.37) min/wk]. Participants also engaged more in moderate PA [265.86 (SD = 335.45) min/wk], than in vigorous PA [50.29 (SD = 205.30) min/wk]. Employment was a significant predictor of overall PA controlling for age, CD4 count and education level. The model explained 2.5% of the variance (R²= 0.025) on overall PA and tested significant at a 0.01 alpha level (p < 0.01). PA interventions for this population should be domain- and intensity-specific. Researchers promoting healthy lifestyle behaviour change can benefit from determining the factors that facilitate domain-specific PA.

A six week contextualised physical activity intervention for women living with HIV and AIDS of low socioeconomic status: a pilot study

Research has consistently shown the benefits of regular physical activity (PA) for women living with HIV and AIDS (WLWHA). This study is a pilot, randomised controlled crossover trial, reporting the effects of a contextualised PA intervention amongst a sample of 21 HIV positive Xhosa-speaking women of low socioeconomic status (SES). The study determined total moderate-to-vigorous PA (TMVPA) as measured subjectively by the Global Physical Activity Questionnaire (GPAQ), total weekly steps (TWS) as measured by a pedometer, and self-efficacy for PA as measured by the Physical Exercise Self-efficacy scale (PESES). Multivariate analysis of covariance (MANCOVA) was used to compute the impact of the intervention on TMVPA, TWS, and self-efficacy for PA from baseline to six weeks, and baseline to 12 weeks post-intervention controlling for pre-test differences in TMVPA. Results showed that participants exposed to the intervention had significant increases in PA as measured by TMVPA (p = .027), TWS (p = .032), as well as exercise self-efficacy (p = .000) from pre-test to 6 weeks. Insignificant findings were reported for all three variables when measured from baseline to 12 weeks. In conclusion, the findings of the pilot study suggest that the intervention was effective in producing significant increases in PA in a sample of PLWHA of low SES over six weeks. Careful consideration of behavioural constructs, such as self-efficacy, can help WLWHA of low SES to adopt regular PA as a complementary therapy for managing their health.

Probiotic guidelines and physician practice: a cross-sectional survey and overview of the literature

Probiotic use by patients and physicians has dramatically increased over the last decade, although definitive evidence is often lacking for their use. We examined probiotic-prescribing practices among health care providers (HCP) at a tertiary medical centre and compared these practices to clinical guidelines. HCP at the Stanford Medical Center received a survey on probiotic prescribing practices including choice of probiotic and primary indications. A broad overview of the literature was performed. Among 2,331 HCP surveyed, 632 responded. Of the 582 of these who routinely prescribed medications, 61% had recommended probiotic foods or supplements to their patients. Women and gastroenterologists were more likely to prescribe probiotics (odds ratio (OR): 1.5, 95% confidence interval (CI): 1.0-2.1; OR: 3.9, 95% CI: 1.5-10.1, respectively). Among probiotic prescribers, 50% prescribed inconsistently or upon patient request, and 40% left probiotic choice to the patient. Common indications for probiotics, particularly Lactobacillus GG, were prevention and treatment of antibiotic-associated diarrhoea (79 and 66%, respectively). Probiotics were often prescribed for ‘general bowel health’ or at patient request (27 and 39% of responders, respectively). Most respondents (63%) thought an electronic medical record (EMR) pop-up would change probiotic prescribing patterns. However, a review of published guidelines and large trials found inconsistencies in probiotic indications, dosages and strain selection. Probiotic prescribing is common but lacks consistency, with choice of probiotic frequently left to the patient, even for indications with some strain-specific evidence. Implementation of EMR pop-ups/pocket guides may increase consistency in probiotic prescribing, although the lack of clear and consistent guidelines must first be addressed with large, well-designed clinical trials.

A survey of probiotic use practices among patients at a tertiary medical centre

Probiotic use has skyrocketed in recent years. Little is known, however, about patient knowledge and practices regarding probiotic use, especially in the context of antibiotic use. An invitation to complete a short, anonymous, electronic survey was sent by email to 965 patients at a tertiary medical centre in California who had agreed to be contacted for participation in research studies. Questions were asked about both probiotic and antibiotic use in the prior three months. Of 333 survey respondents, 55% had recently used probiotics, including food products and/or supplements (90 and 60% of probiotic users, respectively). Women were more likely than men to have used probiotics (odds ratio (OR): 1.99; 95% confidence interval (CI): 1.2-3.4). Health care providers (HCP) had prescribed antibiotics to 79 (24%) respondents in the preceding three months. Among antibiotic users, 33% had initiated or changed probiotics at the time of antibiotic use, usually without a recommendation from their prescribing HCP (72%). Only 12% of those who took probiotics with antibiotics had received a specific recommendation from their HCP. Most patients chose to take probiotic mixtures (56%), with few selecting evidence-based strains, such as Lactobacillus rhamnosus GG (11%). Regular probiotic use among patients is common. Typically, these probiotics are not recommended by a HCP, even in conjunction with antibiotic prescriptions. While a growing body of evidence supports specific probiotic strains for the prevention of antibiotic-associated diarrhoea, patients are often not receiving a specific recommendation from their HCP and appear to be taking strains without guidance from supporting evidence.

Isomerization controlled photopolymerization: effect of dye photophysics on photoinitiation efficiency

The efficiency of free radical polymerization by photoinitiating systems based on two Astrazon orange cyanine dyes was shown to be directly related to the isomerization process of the dye in the excited states. The impact of resin viscosity on photopolymerization reactions was measured and related to the overall radical quantum yields. The quantum yields were calculated according to the photocyclic behaviour of the initiating systems based on the Astrazon orange dyes. These dyes are characterized by a viscosity dependent photophysics, which leads to an isomerization-diffusion-controlled photopolymerization. Besides this demonstration, Astrazon orange dyes appeared to be very good candidates for free radical photopolymerization in the visible, presenting high absorption coefficient, low cost and good sensitivity.

On the interaction of triarylmethane dye crystal violet with LAPONITE® clay: using mineral nanoparticles to control the dye photophysics

The combination of an organic dye with clays leads to very interesting hybrid materials with original properties.

Quaternary ammonium salts of phenylglyoxylic acid as photobase generators for thiol-promoted epoxide photopolymerization

A novel series of photobase generators (PBGs), which are quaternary ammonium salts of phenylglyoxylic acid (PA) having the ability to generate strong bases such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,1,3,3-tetramethylguanidine (TMG), was synthesized.

Interleukin-6 and high mobility group box protein-1 in synovial membranes and osteochondral fragments in equine osteoarthritis

Cytokine production in synovial membranes (SM) and osteochondral fragments (OCF) may influence the development of equine osteoarthritis (OA). In this study, the presence of interleukin (IL)-6 and cytoplasmic and extracellular high mobility group box protein (HMGB)-1 in SM and osteochondral tissue from healthy and diseased equine joints was investigated by immunohistochemistry. Additionally, microscopic synovitis was graded. IL-6 was commonly found in SM cells and in chondrocytes in uncalcified cartilage of OCF, whereas little staining was detected in healthy cartilage. Cytoplasmic and/or extracellular HMGB-1 was widespread only in SM from diseased joints, and also detected in OCF in areas of cartilage damage, fibrous repair tissue, and tidemark reduplication. Joints with OCF and cartilage lesions (without OCF) showed significantly higher median synovitis scores than healthy joints (p=0.013 and p=0.042, respectively). The study identifies OCF as a source of inflammatory mediators in equine OA, as shown by the presence of IL-6 and extracellular HMGB-1 in the fragment. Based upon HMGB-1 release in SM and OCF, further studies to investigate possible involvement of HMGB-1 in the pathogenesis of OA are warranted.

Interleukin-6 and tumour necrosis factor in synovial fluid from horses with carpal joint pathology

The carpal joints are common sites of traumatic arthritis and osteoarthritis (OA) in athletic horses. The pro-inflammatory cytokines interleukin (IL)-6 and tumour necrosis factor (TNF) may be of great importance in the development of intra-articular lesions. The aim of the present study was to investigate possible associations between synovial fluid levels of bioactive IL-6 and TNF and different types of joint lesions seen in traumatic arthritis and OA. Synovial fluid was collected from horses with carpal lameness immediately before arthroscopic surgery. Articular cartilage, synovial membranes and intra-articular ligaments were assessed macroscopically at arthroscopy. Synovial fluid levels of IL-6 and TNF were determined by bioassays, and the cytokine levels between different grades of morphologic changes in each type of assessed tissue were compared. The highest levels of IL-6 were detected in joints with chip fractures. All joints with chip fractures also showed some degree of synovitis. Tumour necrosis factor bioactivity was low and not associated with any joint lesion. Hence, TNF is not useful as a biomarker indicating a specific joint lesion in equine traumatic arthritis or OA. We conclude that a dramatic increase of IL-6 in synovial fluid indicates the presence of osteochondral fragmentation, although low or undetectable levels of IL-6 do not exclude chip fractures. The role of IL-6 in the disease process of osteochondral fragmentation needs further investigation.

Cryptococcus neoformans var. gattii in the koala (Phascolarctos cinereus): serological evidence for subclinical cryptococcosis

Cryptococcus neoformans var. gattii has been shown to have a strong association with eucalypts frequently used by koalas and, not surprisingly, it has been shown to colonize the nasal cavities of koalas. The progression from nasal colonization to tissue invasion is critical to understanding the pathogenesis of cryptococcosis in this species and provides a model for pathogenesis of cryptococcosis in other species. Cryptococcal antigenaemia was detected in twenty-eight healthy koalas from three different regions. This was interpreted as representing limited subclinical disease. One koala developed cryptococcal pneumonia 6 months after leaving the study, whereas another developed cryptococcal meningoencephalitis during the course of the study. Opportunistic necropsies on ten antigen-positive koalas resulted in discovery of small cryptococcal lesions in two (paranasal sinus and lung, respectively). Our data suggest that cryptococcal antigenaemia occurs commonly in koalas, especially in areas with a high environmental presence of C n. var. gattii. Subclinical disease appears most likely to manifest as a small focal lesion in the respiratory tract. Possible outcomes include elimination by an effective immune response, quiescence with possibility of later re-activation or direct progression to overt disease. Symptomatic and subclinical cases showed differences in levels of antigenaemia. The data presented have significant implications for koalas in captivity.

Microbial analysis of Malaysian tempeh, and characterization of two bacteriocins produced by isolates of Enterococcus faecium

AIMS

Isolation of bacteriocinogenic lactic acid bacteria (LAB) from the Malaysian mould-fermented product tempeh and characterization of the produced bacteriocin(s).

METHODS AND RESULTS

LAB were present in high numbers in final products as well as during processing. Isolates, Enterococcus faecium B1 and E. faecium B2 (E. faecium LMG 19827 and E. faecium LMG 19828, respectively) inhibited Gram-positive indicators, including Listeria monocytogenes. Partially purified bacteriocins showed a proteinaceous nature. Activity was stable after heat-treatment except at alkaline pH values. Both strains displayed a bacteriostatic mode of action. Bacteriocin production was associated with late exponential/early stationary growth. Molecular mass, calculated by SDS-PAGE, was 3.4 kDa for B1 bacteriocin, and 3.4 kDa and 5.8 kDa for B2 bacteriocins. PCR screening of enterocin-coding genes revealed three amplified fragments in total genomic DNA that may correspond with PCR signals for enterocin P, enterocin L50A and enterocin L50B. Both B1 and B2 contained a 42-kb plasmid. No differences in bacteriocinogenic capacity were found between wild type strains and plasmid-cured strains.

CONCLUSIONS

It was possible to isolate bacteriocinogenic E. faecium active against various Gram-positive bacteria from final products of tempeh.

SIGNIFICANCE AND IMPACT OF THE STUDY

A first step in applying biopreservation to fermented South-east Asian foods is to obtain bacteriocinogenic LAB from this source. Such isolates may also be used for biopreservation of mould-fermented foods in general, including various types of mould-ripened cheese.

Isolation in blood and marrow transplantation

This phenomenological study explored the perceptions of 20 patients who had undergone an autologous bone marrow transplantation (ABMT). Transcripts from interviews were analyzed for themes. Three themes emerged related to the experience of isolation during and after ABMT: physical isolation (protecting self and others), emotional isolation (protecting self and others), and physical and emotional isolation (supporting self and others). During physical isolation, participants were protected from infection and tried to protect family and friends from emotional burden. However, physical isolation often led to emotional isolation, which the physical presence of others ameliorated, particularly when an emotional presence was coexistent. Emotional presence was a main source of social support. Participants felt family and friends needed more guidance on ways to provide effective support. An important implication for health care professionals is that emotional support in the form of positive presencing should accompany providing information to both patients and family members.

Screening markers for chronic atrophic gastritis in Chiapas, Mexico

Intestinal-type gastric adenocarcinomas usually are preceded by chronic atrophic gastritis. Studies of gastric cancer prevention often rely on identification of this condition. In a clinical trial, we sought to determine the best serological screening method for chronic atrophic gastritis and compared our findings to the published literature. Test characteristics of potential screening tests (antibodies to Helicobacter pyloni or CagA, elevated gastrin, low pepsinogen, increased age) alone or in combination were examined among consecutive subjects enrolled in a study of H. pylori and preneoplastic gastric lesions in Chiapas, Mexico; 70% had chronic atrophic gastritis. English-language articles concerning screening for chronic atrophic gastritis were also reviewed. Sensitivity for chronic atrophic gastritis was highest for antibodies to H. pylori (92%) or CagA, or gastrin levels >25 ng/l (both 83%). Specificity, however, was low for these tests (18, 41, and 22%, respectively). Pepsinogen levels were highly specific but insensitive markers of chronic atrophic gastritis (for pepsinogen I <25 microg/l, sensitivity was 6% and specificity was 100%; for pepsinogen I:pepsinogen II ratio <2.5, sensitivity was 14% and specificity was 96%). Combinations of markers did not improve test characteristics. Screening test characteristics from the literature varied widely and did not consistently identify a good screening strategy. In this study, CagA antibodies alone had the best combination of test characteristics for chronic atrophic gastritis screening. However, no screening test was both highly sensitive and highly specific for chronic atrophic gastritis.

Gastric atrophy and extent of intestinal metaplasia in a cohort of Helicobacter pylori-infected patients

Atrophy and intestinal metaplasia (IM) are preneoplastic gastric lesions associated with Helicobacter pylori infection. Atrophy and IM are usually found together; however, the association between increasing degrees of severity of both atrophy and IM has not been evaluated completely. Two pathologists graded atrophy and IM using the visual analog scale of the Sydney classification in gastric biopsies from 368 H pylori-infected patients. Extent of IM also included determining the number of specimens affected. We then correlated the degree of atrophy with the degree and number of specimens affected with IM by calculating relative risks (RR) and 95% confidence intervals (95% CI). The mean number of biopsies examined from each patient was 6.5. Atrophy and IM were found more frequently in the antrum (85% and 75% of biopsies, respectively). One hundred thirty-eight patients had a combination of atrophy and IM, 48 had IM only, and 89 had atrophy only. Fifty-three subjects had mild atrophy and IM (RR = 1.57; 95% CI 1.2-2.1), 69 had moderate atrophy and IM (RR = 1.86; 95% CI 1.9-2.4), and 16 had marked atrophy and IM (RR = 2.47; 95% CI 1.8-3.3). The median number of biopsy specimens with IM increased from 0 in subjects with no atrophy to 3 in subjects with severe atrophy. The degree of IM correlated with the degree of atrophy; the median degree was 0.6 in subjects with no atrophy and increased to 2.32 in those with severe atrophy. Our data suggest that higher degrees of IM in an individual specimen and increasing number of specimens with IM are associated with moderate or severe degrees of atrophy.

Interobserver variability in application of the revised Sydney classification for gastritis

The Sydney classification for gastritis provides guidelines for histological grading of gastric biopsies. In an ongoing study of gastric preneoplastic lesions in Chiapas, Mexico, 7 biopsies from 150 patients (4 from the antrum and 3 from the body) were obtained during endoscopy and studied histologically. The first 74 endoscopy specimens were read independently by 2 general surgical pathologists. We assessed diagnostic concordance using kappa statistics. The 2 pathologists then jointly reviewed biopsies about which they had disagreed to reach a final diagnosis. A second group of 76 endoscopies was subsequently evaluated independently by the 2 pathologists, and concordance was again assessed. In the first group of biopsies, we found low concordance rates (Heliobacter pylori 0.59, acute inflammation 0.22, intestinal metaplasia 0.60, and atrophy 0.04). In the second group, of independently reviewed cases, there was better concordance (H pylori 0.77, acute inflammation 0.50, intestinal metaplasia 0.70, and atrophy 0.64). We presumed that use of the Sydney classification would result in minimal interpretational differences achieving ideal kappas greater than 0.80. Because pathology results are based on subjective interpretation of this classification, complete diagnostic agreement is practically impossible. Concordance by general surgical pathologists after joint review of cases was similar to that obtained by gastrointestinal pathologists.

Prevalence and incidence of herpes simplex virus type 2 infection among male Zimbabwean factory workers

Stored sera from a cohort of 2397 male factory workers in Harare, Zimbabwe, were screened for herpes simplex virus type 2 (HSV-2)-specific antibodies, to estimate the prevalence and incidence of genital herpes infection and to assess the relation between HSV-2 and human immunodeficiency virus (HIV) acquisition. The prevalence of HSV-2 at enrollment was 39.8%. Correlates of HSV-2 seropositivity were HIV seropositivity, marital status, history of sexually transmitted disease (STD), older age, and higher income. The incidence of HSV-2 seroconversion during follow-up was 6.2/100 person-years. Correlates of HSV-2 seroconversion were enrollment while HIV-positive or seroconversion during follow-up, reported genital ulcer, history of STD, and number of sex partners. No evidence was found that HSV-2 infection was more likely to precede HIV or vice versa. HSV-2 and HIV seropositivity are strong markers for high-risk sexual behavior. Improved interventions targeted to populations in which the incidence of either viral infection is high are needed.

Safety and efficacy of shed mediastinal blood transfusion after cardiac surgery: a multicenter observational study. Multicenter Study of Perioperative Ischemia Research Group

OBJECTIVE

To examine the efficacy and safety of shed mediastinal blood (SMB) transfusion in preventing allogenic red blood cell (RBC) transfusion.

DESIGN

An observational clinical study.

SETTING

Twelve US academic medical centers.

PARTICIPANTS

Six hundred seventeen patients undergoing elective primary coronary artery bypass grafting.

INTERVENTIONS

Patients were administered SMB transfusion or not, according to institutional and individual practice, without random assignment.

MEASUREMENTS AND RESULTS

The independent effect of SMB transfusion on postoperative RBC transfusion was examined by multivariable modeling. Potential complications of SMB transfusion, such as bleeding and infection, were examined. Three hundred twelve of the study patients (51%) received postoperative SMB transfusion (mean volume, 554 +/- 359 mL). Patients transfused with SMB had significantly lower volumes of RBC transfusion than those not receiving SMB (0.86 +/- 1.50 v 1.08 +/- 1.65 units; p < 0.05). However, multivariable analysis showed that SMB transfusion was not predictive of postoperative RBC transfusion. Demographic factors (older age, female sex), institution, and postoperative events (greater chest tube drainage, lower hemoglobin level on arrival to the intensive care unit, and use of inotropes) were significant predictors of RBC transfusion. The volume of chest tube drainage on the operative day (707 +/- 392 v 673 +/- 460 mL; p = 0.30), reoperation for hemorrhage (3.1% v2.5%; p = 0.68), and overall frequency of infection (5.8% v 6.6%; p = 0.81) were similar between patients receiving and not receiving SMB, respectively. However, in patients who did not receive allogenic RBC transfusion, there was a significantly greater frequency of wound infection in the SMB group (3.6% v0%; p = 0.02).

CONCLUSION

These data suggest that SMB is ineffective as a blood conservation method and may be associated with a greater frequency of wound infection.

Cerebral injury after cardiac surgery: identification of a group at extraordinary risk. Multicenter Study of Perioperative Ischemia Research Group (McSPI) and the Ischemia Research Education Foundation (IREF) Investigators

BACKGROUND AND PURPOSE

Cerebral injury after cardiac surgery is now recognized as a serious and costly healthcare problem mandating immediate attention. To effect solution, those subgroups of patients at greatest risk must be identified, thereby allowing efficient implementation of new clinical strategies. No such subgroup has been identified; however, patients undergoing intracardiac surgery are thought to be at high risk, but comprehensive data regarding specific risk, impact on cost, and discharge disposition are not available.

METHODS

We prospectively studied 273 patients enrolled from 24 diverse US medical centers, who were undergoing intracardiac and coronary artery surgery. Patient data were collected using standardized methods and included clinical, historical, specialized testing, neurological outcome and autopsy data, and measures of resource utilization. Adverse outcomes were defined a priori and determined after database closure by a blinded independent panel. Stepwise logistic regression models were developed to estimate the relative risks associated with clinical history and intraoperative and postoperative events.

RESULTS

Adverse cerebral outcomes occurred in 16% of patients (43/273), being nearly equally divided between type I outcomes (8.4%; 5 cerebral deaths, 16 nonfatal strokes, and 2 new TIAs) and type II outcomes (7.3%; 17 new intellectual deterioration persisting at hospital discharge and 3 newly diagnosed seizures). Associated resource utilization was significantly increased--prolonging median intensive care unit stay from 3 days (no adverse cerebral outcome) to 8 days (type I; P<0.001) and from 3 to 6 days (type II; P<0.001), and increasing hospitalization by 50% (type II, P=0.04) to 100% (type I, P<0.001). Furthermore, specialized care after hospital discharge was frequently necessary in those with type I outcomes, in that only 31% returned home compared with 85% of patients without cerebral complications (P<0.001). Significant risk factors for type I outcomes related primarily to embolic phenomena, including proximal aortic atherosclerosis, intracardiac thrombus, and intermittent clamping of the aorta during surgery. For type II outcomes, risk factors again included proximal aortic atherosclerosis, as well as a preoperative history of endocarditis, alcohol abuse, perioperative dysrhythmia or poorly controlled hypertension, and the development of a low-output state after cardiopulmonary bypass.

CONCLUSIONS

These prospective multicenter findings demonstrate that patients undergoing intracardiac surgery combined with coronary revascularization are at formidable risk, in that 1 in 6 will develop cerebral complications that are frequently costly and devastating. Thus, new strategies for perioperative management--including technical and pharmacological interventions--are now mandated for this subgroup of cardiac surgery patients.

Hematocrit value on intensive care unit entry influences the frequency of Q-wave myocardial infarction after coronary artery bypass grafting. The Institutions of the Multicenter Study of Perioperative Ischemia (McSPI) Research Group

OBJECTIVES

No data exist regarding "the best" hematocrit value after coronary artery bypass graft surgery. Transfusion practice varies, because neither an optimal hematocrit value nor a uniform transfusion trigger criterion has been determined.

METHODS

To investigate the optimal hematocrit value, we studied 2202 patients undergoing coronary bypass. The hematocrit value on entry into the intensive care unit (IHCT) was categorized into three groups: high (> or = 34%), medium (25% to 33%), and low (< or = 24%). Characteristics and adverse events (outcomes) were compared, and the effect of IHCT on the risk of myocardial infarction was determined by logistic regression.

RESULTS

High IHCT (> or = 34%) was associated with an increased rate of myocardial infarction (8.3% vs 5.5% vs 3.6%; p < or = 0.03, high, medium vs low) and with more severe left ventricular dysfunction (11.7% vs 7.4% and 5.7%; p=0.006, high, medium vs low). Mortality rate increased with higher IHCT when all the high-risk subgroups were combined (8.6% vs 4.5% vs 3.2%; p < 0.001, high, medium vs low). By multivariate analysis, IHCT remained the most significant predictor of adverse outcomes (relative risk high vs low 2.22, 95% confidence interval: 1.04 to 4.76). No characteristic, event, medication, or transfusion therapy confounded the relationship between IHCT and outcome.

CONCLUSION

High IHCT is associated with a higher rate of myocardial infarction and is an independent predictor of infarction. On the basis of the risk of myocardial infarction, there is no rationale for transfusion to an arbitrary level after coronary artery bypass grafting.

The concordance of intraoperative left ventricular wall-motion abnormalities and electrocardiographic S-T segment changes: association with outcome after coronary revascularization. Multicenter Study of Perioperative Ischemia (McSPI) Research Group

BACKGROUND

Transesophageal echocardiography (TEE) and Holter electrocardiography (ECG) are used to detect intraoperative ischemia during coronary artery bypass graft surgery (CABG). Concordance of these modalities and sensitivity as indicators of adverse perioperative cardiac outcomes are poorly defined. The authors tried to determine whether routine use of Holter ECG and TEE in patients with CABGs has clinical value in identifying those patients in whom myocardial infarction (MI) is likely to develop.

METHODS

A total of 351 patients with CABG and both ECG- and TEE-evaluable data were examined for the occurrence of ischemia and infarction. The TEE and five-lead Holter ECGs were performed continuously during cardiac surgery. The incidence of MI (creatine kinase-MB > or = 100 ng/ml) within 12 h of arrival in the intensive care [ICU] unit, new ECG Q wave on ICU admission or on the morning of postoperative day 1, or both, were recorded.

RESULTS

Electrocardiographic or TEE evidence of intraoperative ischemia was present in 126 (36%) patients. The concordance between modalities was poor (positive concordance = 17%; Kappa statistic = 0.13). Myocardial infarction occurred in 62 (17%) patients, and 32 (52%) of them had previous intraoperative ischemia. Of these, 28 (88%) were identified by TEE, whereas 13 (41%) were identified by ECG. Prediction of MI was greater for TEE compared with ECG.

CONCLUSIONS

Wall-motion abnormalities detected by TEE are more common than S-T segment changes detected by ECG, and concordance between the two modalities is low. One half of patients with MI had preceding ECG or TEE ischemia. Logistic regression revealed that TEE is twice as predictive as ECG in identifying patients who have MI.

Adverse cerebral outcomes after coronary bypass surgery. Multicenter Study of Perioperative Ischemia Research Group and the Ischemia Research and Education Foundation Investigators

BACKGROUND

Acute changes in cerebral function after elective coronary bypass surgery is a difficult clinical problem. We carried out a multicenter study to determine the incidence and predictors of -- and the use of resources associated with -- perioperative adverse neurologic events, including cerebral injury.

METHODS

In a prospective study, we evaluated 2108 patients from 24 U.S. institutions for two general categories of neurologic outcome: type I (focal injury, or stupor or coma at discharge) and type II (deterioration in intellectual function, memory deficit, or seizures).

RESULTS

Adverse cerebral outcomes occurred in 129 patients (6.1 percent). A total of 3.1 percent had type I neurologic outcomes (8 died of cerebral injury, 55 had nonfatal strokes, 2 had transient ischemic attacks, and 1 had stupor), and 3.0 percent had type II outcomes (55 had deterioration of intellectual function and 8 had seizures). Patients with adverse cerebral outcomes had higher in-hospital mortality (21 percent of patients with type I outcomes died, vs. 10 percent of those with type II and 2 percent of those with no adverse cerebral outcome; P<0.001 for all comparisons), longer hospitalization (25 days with type I outcomes, 21 days with type II, and 10 days with no adverse outcome; P<0.001), and a higher rate of discharge to facilities for intermediate- or long-term care (69 percent, 39 percent, and 10 percent ; P<0.001). Predictors of type I outcomes were proximal aortic atherosclerosis, a history of neurologic disease, and older age; predictors of type II outcomes were older age, systolic hypertension on admission, pulmonary disease, and excessive consumption of alcohol.

CONCLUSIONS

Adverse cerebral outcomes after coronary bypass surgery are relatively common and serious; they are associated with substantial increases in mortality, length of hospitalization, and use of intermediate- or long-term care facilities. New diagnostic and therapeutic strategies must be developed to lessen such injury.

Cardiovascular responses during sedation after coronary revascularization. Incidence of myocardial ischemia and hemodynamic episodes with propofol versus midazolam. Institutions of the McSPI Research Group

BACKGROUND

Propofol sedation offers advantages for titration and rapid emergence in the critically ill patient, but concern for adverse hemodynamic effects potentially limits its use in these patients. The current study compares the cardiovascular effects of sedation with propofol versus midazolam during the first 12 h after coronary revascularization.

METHODS

Three hundred fifty-one patients undergoing coronary revascularization were anesthetized using a standardized sufentanil/midazolam regimen, and assigned randomly to 12 h of sedation with either propofol or midazolam while tracheally intubated. The incidence and characteristics of hemodynamic episodes, defined as heart rate less than 60 or greater than 100 beats/min or systolic blood pressure greater than 140 or less than 90 mmHg, were determined using data electronically recorded at 1-min intervals. The presence of myocardial ischemia was determined using continuous three-channel Holter electrocardiography (ECG) and of myocardial infarctions (MI) using 12-lead ECG (Q wave MI, Minnesota Code) or creatine kinase isoenzymes (CK-MB) analysis (non-Q wave MI, peak CK-MB > 70 ng/ml, or CK-MB > 70 IU/I).

RESULTS

Ninety-three percent of patients in both treatment groups had at least one hemodynamic episode during the period of postoperative sedation. Propofol sedation resulted in a 17% lower incidence of tachycardia (58% vs. 70%, propofol vs. midazolam; P = 0.04), a 28% lower incidence of hypertension (39% vs. 54%; P = 0.02), and a greater incidence of hypotension (68% vs. 51%; P = 0.01). Despite these hemodynamic effects, the incidence of myocardial ischemia did not differ between treatment groups (12% propofol vs. 13% midazolam; P = 0.66), nor did its severity, as measured by ischemic minutes per hour monitored (8.7 +/- 5.8 vs. 6.2 +/- 4.6 min/h, propofol vs. midazolam; P = 0.19) or ischemic area under the curve (6.8 +/- 4.0 vs. 5.3 +/- 4.2; P = 0.37). The incidence of cardiac death (one per group), Q wave MI (propofol, n = 7; midazolam, n = 3; P = 0.27), or non Q wave MI (propofol, n = 16; midazolam, n = 18; P = 0.81) did not differ between treatment groups.

CONCLUSIONS

Hemodynamic episodes occur frequently in the first 12 h after coronary revascularization. Compared with a standard sedation regimen (midazolam), propofol sedation appears to modulate postoperative hemodynamic responses by reducing the incidence and severity of tachycardia and hypertension and increasing the incidence of hypotension. Both sedation regimens appear similarly safe with respect to myocardial ischemia. These findings indicate that propofol infusion provides effective sedation without deleterious hemodynamic effects in patients recovering from cardiac surgery.

Case-control study of risk factors for incident Lyme disease in California

To identify risk factors for incident Lyme disease in California during the period June 1, 1991 to December 31, 1992, the authors compared the activities of 101 cases of physician-diagnosed erythema migrans ascertained via both active and passive surveillance with those of 107 controls matched on sex, age, and neighborhood. Questions asked by telephone pertained to location of home, presence of wildlife around the house, hours of outdoor work and outdoor leisure activities, pet ownership, precautionary measures to avoid tick bites, tick removal methods, and knowledge about Lyme disease. For cases, activities pertained to the month prior to the onset of erythema migrans; controls were interviewed about the same activities during the same one-month period. The observation of deer and lizards around the home and a history of exposure to ticks were associated with Lyme disease (deer, odds ratio (OR) = 2.53, 95% confidence interval (CI) 1.25-5.15; lizards, OR = 2.14, 95% CI 1.14-4.04). However, the only activity associated with Lyme disease was the use for more than 5 hours per week of wide maintained trails (OR = 11.33, 95% CI 1.33-123.5); this association occurred only in persons with other outdoor leisure activities. No other behaviors or activities were identified as risk factors for acquisition of Lyme disease in California.