The effects of lifestyle and behavioural interventions on cancer recurrence, overall survival and quality of life in breast cancer survivors: A systematic review and network meta-analysis

Lifestyle/behavioural interventions may improve breast cancer outcomes and quality of life (QoL); however, uncertainty remains about the most effective interventions due to limited evidence. This study aimed to assess and compare the effects of lifestyle/behavioural interventions on cancer recurrence, survival and QoL in breast cancer survivors. Electronic databases including Medline, EMBASE, PsycINFO, CINAHL and EBM Reviews were searched for relevant literature. Randomized controlled trials (RCTs) and quasi-RCTs comparing a lifestyle/behavioural intervention with a control condition in breast cancer survivors were included. Outcomes included cancer recurrence, overall survival and QoL. A network meta-analysis synthesized intervention effect. Studies not included in the analysis were reported narratively. Of 6251 identified articles, 38 studies met the selection criteria. Limited evidence exists on the impacts of lifestyle/behavioural interventions on breast cancer recurrence/survival. Exercise was identified as the most effective intervention in improving overall survival (HR 0.50, 95 % CI 0.36, 0.68). Lifestyle/behavioural interventions may improve QoL; psychosocial interventions (SMD 1.28, 95 % CI 0.80, 1.77) and aerobic-resistance exercise (SMD 0.33, 95 % CI -0.03, 0.69) were the most effective interventions to enhance QoL. This review highlights potential post-breast cancer benefits from lifestyle/behavioural interventions, notably exercise and psychosocial support for QoL and exercise for overall survival. Thus, encouraging active lifestyle, stress management and coping skills programs during and after cancer treatment may enhance physical wellbeing and QoL. However, the findings should be interpreted with caution due to the small number and sample sizes of studies. Future longer-term RCTs are required for conclusive recommendations.

How midwives facilitate informed decisions in the third stage of labour - an exploration through portraiture

PROBLEM

Midwifery philosophy promotes informed decision-making. Despite this, midwives report a lack of informed decision-making in standard maternity care systems.

BACKGROUND

Previous research has shown a woman's ability to make informed decisions within her maternity care significantly impacts her childbearing experience. When informed decision-making is facilitated, women report positive experiences, whereas when lacking, there is an increased potential for birth trauma.

AIM

To explore midwives' experiences of facilitating informed decision-making, using third-stage management as context.

METHODS

Five midwives from Victoria, Australia, were interviewed about their experiences with informed decision-making. These interviews were guided by portraiture methodology whereby individual narrative portraits were created. This paper explores the shared themes among these five portraits.

FINDINGS

Five individual narrative portraits tell the stories of each midwife, providing rich insight into their philosophies, practices, barriers and enablers of informed decision-making. These are then examined as a whole dataset to explore shared themes, and include; 'informed decision-making is fundamental to midwifery practice' 'the system', and 'navigating the system'. The system contained the sub-themes; hierarchy in hospitals, the medicalisation of birth, and the impact on midwifery practice, and 'navigating the system' - contained; safety of the woman and safety of the midwife, and the gold-standard of midwifery.

DISCUSSION AND CONCLUSION

Midwives in this study valued informed decision-making as fundamental to their philosophy but also faced barriers in their ability to facilitate it. Barriers to informed decision-making included: power-imbalances; de-skilling in physiological birth; fear of blame, and interdisciplinary disparities. Conversely enablers included continuity models of midwifery care, quality antenatal education, respectful interdisciplinary collaboration and an aim toward a resurgence of fundamental midwifery skills.

Introducing and integrating perinatal mental health screening: development of an equity-informed evidence-based approach

BACKGROUND

Pregnancy is a time of increased risk for developing or re-experiencing mental illness. Perinatal mental health screening for all women is recommended in many national guidelines but a number of systems-level and individual barriers often hinder policy implementation. These barriers result in missed opportunities for detection and early intervention and are likely to be experienced disproportionately by women from culturally and linguistically diverse backgrounds, including women of refugee backgrounds. The objectives of this study were to develop a theory-informed, evidence-based guide for introducing and integrating perinatal mental health screening across health settings; and to synthesise the learnings from an implementation initiative and multi-sectoral partnership between the Centre of Perinatal Excellence (COPE), and a university-based research centre. COPE is a non-governmental organisation commissioned to update the Australian perinatal mental health guidelines, train health professionals and implement digital screening.

METHODS

In this case study, barriers to implementation were prospectively identified and strategies to overcome them were developed. A pilot perinatal screening program for depression and anxiety with a strong health equity focus was implemented and evaluated at a large public maternity service delivering care to a culturally diverse population of women in metropolitan Melbourne, Australia, including women of refugee background. Strategies identified pre-implementation and post-evaluation were mapped to theoretical frameworks. An implementation guide was developed to support future policy, planning and decision-making by healthcare organisations.

RESULTS

Using a behavioural change framework (COM-B), the key barriers, processes, and outcomes are described for a real-world example designed to maximise accessibility, feasibility, and acceptability. A program logic model was developed to demonstrate the relationships of the inputs, which included stakeholder consultation, resource development, and a digital screening platform, with the outcomes of the program. A seven-stage implementation guide is presented for use in a range of healthcare settings.

CONCLUSIONS

These findings describe an equity-informed, evidence-based approach that can be used by healthcare organisations to address common systems and individual level barriers to implement perinatal depression and anxiety screening guidelines.

PATIENT OR PUBLIC CONTRIBUTION

These results present strategies that were informed by prior research involving patients and staff from a large public antenatal clinic in Melbourne, Australia. This involved interviews with health professionals from the clinic such as midwives, obstetricians, perinatal mental health and refugee health experts, and interpreters. Interviews were also conducted with women of refugee background who were attending the clinic for antenatal care. A steering committee was formed to facilitate the implementation of the perinatal mental health screening program comprising staff from key hospital departments, GP liaison, refugee health and wellbeing, the Non-Governmental Organization (NGO) COPE and academic experts in psychology, midwifery, obstetrics and public health. This committee met fortnightly for two years to devise strategies to address the barriers, implement and evaluate the program. A community advisory group was also formed which involved women from eight different countries, some of refugee background, who had recently given birth at the health service. This committee met bi-monthly and was instrumental in planning the implementation and evaluation such as recruitment strategies, resources, and facilitating an understanding of the cultural complexity of the women participating in the study. This article is protected by copyright. All rights reserved.

Blended (online and in-person) Women's Health Interprofessional Learning by Simulation (WHIPLS) for medical and midwifery students

BACKGROUND

Blended teaching combines traditional in-person components (simulation-based training and clinical-based placement) with online resources. Due to the COVID-19 pandemic, we modified our Women's Health Interprofessional Learning through Simulation (WHIPLS) program - to develop core obstetric and gynaecological skills - into a blended teaching program. There is limited literature reporting the observations of blended teaching on learning.

AIMS

To qualitatively evaluate the blended teaching program and explore how it contributes to learning.

MATERIALS AND METHODS

This study was performed at Monash University in Melbourne, Australia. A total of 98 medical students and 39 midwifery students participated. Data were collected by written survey and analysed by authors using a thematic analysis framework.

RESULTS

Students reported that in-person teaching remains a vital aspect of their curriculum, contributing an averaged 63.2% toward an individual's learning, compared with online. Five substantial themes demonstrate how students learnt and maximised education opportunities using a blended teaching program: 'low-pressure simulation environments', 'peer-assisted learning', 'haptic learning', 'scaffolded learning' and 'the impact of online discourse'.

DISCUSSION

In-person teaching remains a cornerstone of obstetric and gynaecological clinical skills education, of which interprofessional simulation and clinical-based placement are key components. Teaching via online discourse alone, is not sufficient to completely replace and provide comparable learning outcomes, but certainly plays an important role to prime students' learning and to maximise in-person opportunities and resources. Our study reveals key pedagogies of a blended (online and in-person) learning program, providing further evidence to support its ongoing utility as a feasible and warranted approach to learning.

Racism, healthcare access and health equity for people seeking asylum

People seeking asylum are at risk of receiving poorer quality healthcare due, in part, to racist and discriminatory attitudes, behaviours and policies in the health system. Despite fleeing war and conflict; exposure to torture and traumatic events and living with uncertainty; people seeking asylum are at high-risk of experiencing long-term poor physical and mental health outcomes in their host country. This article aims to raise awareness and bring attention to some common issues people seeking asylum face when seeking healthcare in high-income countries where the health system is dominated by a Western biomedical view of health. Clinical case scenarios are used to highlight instances of racist healthcare policies and practices that create and maintain ongoing health disparities; limited access to culturally and linguistically appropriate health services, and lack of trauma-informed approaches to care. Nurses and midwives can play an important role in countering racism in healthcare settings; by identifying and calling out discriminatory practice and modelling tolerance, respect and empathy in daily practice. We present recommendations for individuals, organisations and governments that can inform changes to policies and practices that will reduce racism and improve health equity for people seeking asylum.

Improving Mental Health in Pregnancy for Refugee Women: Protocol for the Implementation and Evaluation of a Screening Program in Melbourne, Australia

BACKGROUND

Identifying mental health disorders in migrant and refugee women during pregnancy provides an opportunity for interventions that may benefit women and their families. Evidence suggests that perinatal mental health disorders impact mother-infant attachment at critical times, which can affect child development. Postnatal depression resulting in suicide is one of the leading causes of maternal mortality postpartum. Routine screening of perinatal mental health is recommended to improve the identification of depression and anxiety and to facilitate early management. However, screening is poorly implemented into routine practice. This study is the first to investigate routine screening for perinatal mental health in a maternity setting designed for refugee women. This study will determine whether symptoms of depression and anxiety are more likely to be detected by the screening program compared with routine care and will evaluate the screening program's feasibility and acceptability to women and health care providers (HCPs).

OBJECTIVE

The objectives of this study are (1) to assess if refugee women are more likely to screen risk-positive for depression and anxiety than nonrefugee women, using the Edinburgh Postnatal Depression Scale (EPDS); (2) to assess if screening in pregnancy using the EPDS enables better detection of symptoms of depression and anxiety in refugee women than current routine care; (3) to determine if a screening program for perinatal mental health in a maternity setting designed for refugee women is acceptable to women; and (4) to evaluate the feasibility and acceptability of the perinatal mental health screening program from the perspective of HCPs (including the barriers and enablers to implementation).

METHODS

This study uses an internationally recommended screening measure, the EPDS, and a locally developed psychosocial questionnaire, both administered in early pregnancy and again in the third trimester. These measures have been translated into the most common languages used by the women attending the clinic and are administered via an electronic platform (iCOPE). This platform automatically calculates the EPDS score and generates reports for the HCP and woman. A total of 119 refugee women and 155 nonrefugee women have been recruited to evaluate the screening program's ability to detect depression and anxiety symptoms and will be compared with 34 refugee women receiving routine care. A subsample of women will participate in a qualitative assessment of the screening program's acceptability and feasibility. Health service staff have been recruited to evaluate the integration of screening into maternity care.

RESULTS

The recruitment is complete, and data collection and analysis are underway.

CONCLUSIONS

It is anticipated that screening will increase the identification and management of depression and anxiety symptoms in pregnancy. New information will be generated on how to implement such a program in feasible and acceptable ways that will improve health outcomes for refugee women.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/13271.

Abstract P5-22-11: Enhanced intraoperative breast specimen assessment may reduce margin positivity and reoperation rates in breast cancer

Introduction: Partial mastectomy is the most commonly performed operation for breast cancer. Margin positivity throughout the nation ranges from 30-60%, of which 10-36% require reoperation. Data from the SHAVE trial showed that excising an additional 1 cm margin circumferentially can reduce margin positivity by 50%. We are concerned about the large volume of tissue that may be unnecessarily removed secondary to routine circumferential margin excision. We have practiced selective additional margin excision based on enhanced intraoperative margin assessment including gross specimen evaluation by pathology. We suggest that enhanced intraoperative specimen assessment may reduce margin positivity and reoperation rates.

Methods: This is a retrospective review of a prospectively maintained, single surgeon database of patients undergoing partial mastectomy between Feburary 2014 – December 2016 at Medstar Union Memorial Hospital. One hundred consecutive patients diagnosed with DCIS or invasive carcinoma undergoing partial mastectomy with the intention of margin negativity were included. Information regarding preoperative planning and intraoperative specimen assessment were collected from clinical notes and operative records. These data points included preoperative imaging studies, use of preoperative needle localization, intraoperative ultrasound to guide surgery, use of intraoperative Faxitron, and gross pathologic consultation. The data is analyzed to calculate margin positivity and reoperation rates in comparison to reported experiences.

Results: The average age was 62.3 years, ranging from 33-96 years. Of the 100 patients, 73 had invasive cancer, 19 had DCIS. The average lesion size was 14.17mm. There were 8/100 cases with a positive margin, of which 5 cases had re-excisions. An additional 3 cases had re-excision for positive cells <1mm from margin. Faxitron was used in 89% of cases and gross consultation in 100% of cases. The average number of additional margins taken was 1.2. 22/100 cases did not have additional margins taken during the index operation.

Discussion: This is a hypothesis generating study that was prompted by our concern about the amount of tissue and the expense created by routine circumferential margin removal. The issue of variability among different institutions and the very high reoperation rates reported by many beg for an explanation. Many techniques have been proposed to reduce this unexplained variability but none has consistently shown the necessary improvement and many new technologies are costly. Our experience suggests that low margin positivity and reoperation rates may be achieved using inexpensive enhanced intraoperative specimen assessment. We can test this hypothesis by comparing information among the different hospitals in our system. A head to head prospective trial comparing routine shaves versus enhanced specimen assessment and selective additional margins would answer this question.

Conclusion: Enhanced intraoperative margin assessment and selective margin excision may provide a good alternative to routine shave margin while removing less breast tissue. Uniform specimen assessment algorithms may also help achieve reduced margin positivity and reoperation rates.

Citation Format: Tran H-T, Moore I, Patel N, Willey S, Farha M. Enhanced intraoperative breast specimen assessment may reduce margin positivity and reoperation rates in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-22-11.

Antiviral inhibition of enveloped virus release by tetherin/BST-2: action and counteraction

Tetherin (BST2/CD317) has been recently recognized as a potent interferon-induced antiviral molecule that inhibits the release of diverse mammalian enveloped virus particles from infected cells. By targeting an immutable structure common to all these viruses, the virion membrane, evasion of this antiviral mechanism has necessitated the development of specific countermeasures that directly inhibit tetherin activity. Here we review our current understanding of the molecular basis of tetherin's mode of action, the viral countermeasures that antagonize it, and how virus/tetherin interactions may affect viral transmission and pathogenicity.

Extensive complement-dependent enhancement of HIV-1 by autologous non-neutralising antibodies at early stages of infection

BACKGROUND

Non-neutralising antibodies to the envelope glycoprotein are elicited during acute HIV-1 infection and are abundant throughout the course of disease progression. Although these antibodies appear to have negligible effects on HIV-1 infection when assayed in standard neutralisation assays, they have the potential to exert either inhibitory or enhancing effects through interactions with complement and/or Fc receptors. Here we report that non-neutralising antibodies produced early in response to HIV-1 infection can enhance viral infectivity.

RESULTS

We investigated this complement-mediated antibody-dependent enhancement (C'-ADE) of early HIV infection by carrying out longitudinal studies with primary viruses and autologous sera derived sequentially from recently infected individuals, using a T cell line naturally expressing the complement receptor 2 (CR2; CD21). The C'-ADE was consistently observed and in some cases achieved infection-enhancing levels of greater than 350-fold, converting a low-level infection to a highly destructive one. C'-ADE activity declined as a neutralising response to the early virus emerged, but later virus isolates that had escaped the neutralising response demonstrated an increased capacity for enhanced infection by autologous antibodies. Moreover, sera with autologous enhancing activity were capable of C'ADE of heterologous viral isolates, suggesting the targeting of conserved epitopes on the envelope glycoprotein. Ectopic expression of CR2 on cell lines expressing HIV-1 receptors was sufficient to render them sensitive to C'ADE.

CONCLUSIONS

Taken together, these results suggest that non-neutralising antibodies to the HIV-1 envelope that arise during acute infection are not 'passive', but in concert with complement and complement receptors may have consequences for HIV-1 dissemination and pathogenesis.

Complement as an endogenous adjuvant for dendritic cell-mediated induction of retrovirus-specific CTLs

Previous studies have demonstrated the involvement of complement (C) in induction of efficient CTL responses against different viral infections, but the exact role of complement in this process has not been determined. We now show that C opsonization of retroviral particles enhances the ability of dendritic cells (DCs) to induce CTL responses both in vitro and in vivo. DCs exposed to C-opsonized HIV in vitro were able to stimulate CTLs to elicit antiviral activity significantly better than non-opsonized HIV. Furthermore, experiments using the Friend virus (FV) mouse model illustrated that the enhancing role of complement on DC-mediated CTL induction also occurred in vivo. Our results indicate that complement serves as natural adjuvant for DC-induced expansion and differentiation of specific CTLs against retroviruses.

Humoral immunity to HIV-1: neutralisation and antibody effector functions

Several features of HIV have frustrated efforts to develop a vaccine able to induce broadly neutralising antibodies. The enormous genetic diversity of HIV is a major factor, accompanied by the camouflaged nature of the envelope spike, upon which HIV depends for cellular entry and to which antibodies must bind to neutralise. The picture is further complicated by the presence of nonfunctional envelope glycoproteins on the surface of HIV that are immunogenic. Consequently, HIV attracts antibodies that do not directly neutralise the virus but still activate complement and engage Fc receptors, which can both enhance and inhibit infection. The various effects that anti-envelope antibodies have on HIV infection will be reviewed here. Further research is needed to determine if these in vitro-characterised activities have relevance in vivo, and if some of the undesirable effects of non-neutralising antibodies can be avoided or the beneficial effects harnessed.

Effect of tracheal and tongue displacement on upper airway airflow dynamics

We have previously shown that caudal tracheal displacement alters the airflow dynamics of the upper airway. In the present study, we specifically examined the effects of tongue and tracheal displacement on upper airway airflow dynamics. To determine how tongue and tracheal displacement modulate maximal inspiratory airflow (VImax), we analyzed the pressure-flow relationships obtained in the isolated upper airway of paralyzed cats. VImax and its determinants, the pharyngeal critical pressure (Pcrit) and the nasal resistance (Rn) upstream to the flow-limiting site, were measured as tongue displacement and tracheal displacement were systematically varied. Four results were obtained: 1) there was no independent effect of tongue displacement on VImax, Pcrit, or Rn; 2) there was an increase in VImax with 2 cm of tracheal displacement, which was associated with a decrease in Pcrit and an increase in Rn; 3) there was an interactive effect of tongue and tracheal displacement on VImax and Pcrit but not on Rn; and 4) there was a large increase in VImax with tongue displacement > 2.5 cm with the trachea nondisplaced, which was associated with a large decrease in Pcrit and a large increase in Rn. We conclude that tongue and tracheal displacement exert differing influences on airflow dynamics and present a mechanical model of the upper airway that explains these results.

Cocaine and pregnancy: clinical and toxicological implications for the neonate

Recent studies show that the rate of cocaine use by pregnant women in the United States is much higher than realized hitherto, and an increasing number of infants are being born to cocaine-using mothers. In an ongoing research project to study the effects of cocaine on pregnancy outcome, we studied 70 infants born to cocaine-using women. These infants were matched to a drug-free comparison group selected from the population of the same hospital: children of pregnant women of a similar racial and socioeconomic distribution, but with no history or evidence of licit or illicit drug use during pregnancy. Cocaine-exposed infants had lower birth weight, shorter gestation, and a smaller head circumference than control infants. Cocaine-exposed infants also had neurobehavioral abnormalities at initial evaluation and a higher rate of perinatal complications. Toxicological evaluation of urines of neonates born to cocaine-using women showed that benzoylecgonine, a primary metabolite of cocaine, persisted in the urines for as long as 120 h after delivery. We discuss the role of the immature fetal and neonatal system in the clinical and toxicological outcome of the infant, and emphasize that further long-term studies of this will be needed.

Cocaine and pregnancy: clinical and toxicological implications for the neonate

Recent studies show that the rate of cocaine use by pregnant women in the United States is much higher than realized hitherto, and an increasing number of infants are being born to cocaine-using mothers. In an ongoing research project to study the effects of cocaine on pregnancy outcome, we studied 70 infants born to cocaine-using women. These infants were matched to a drug-free comparison group selected from the population of the same hospital: children of pregnant women of a similar racial and socioeconomic distribution, but with no history or evidence of licit or illicit drug use during pregnancy. Cocaine-exposed infants had lower birth weight, shorter gestation, and a smaller head circumference than control infants. Cocaine-exposed infants also had neurobehavioral abnormalities at initial evaluation and a higher rate of perinatal complications. Toxicological evaluation of urines of neonates born to cocaine-using women showed that benzoylecgonine, a primary metabolite of cocaine, persisted in the urines for as long as 120 h after delivery. We discuss the role of the immature fetal and neonatal system in the clinical and toxicological outcome of the infant, and emphasize that further long-term studies of this will be needed.

Effect of blood product medium supplements on the activity of cefotaxime and other cephalosporins against Enterococcus faecalis

The activities of cefotaxime and other aminothiazoyl oxime cephalosporins against Enterococcus faecalis were enhanced by addition of 5% sheep blood to Mueller-Hinton agar. This effect was not seen with aztreonam (aminothiazoyl oxime monobactam), cefotiam (aminothiazoyl, nonoxime), or other cephalosporins, and it was specific to the syn-configuration of the oxime moiety. Enhancement of cefotaxime activity was demonstrable against approximately 50% of 86 clinical isolates and could only be shown at low bacterial inocula. Human serum, serum alpha 1-, beta- and gamma-globulin fractions and albumin often antagonized or did not affect significantly the antimicrobial activity of cefotaxime, while the alpha 2-globulin fraction usually enhanced drug activity. The in vivo activity of cefotaxime against E. faecalis was examined in a rat peritoneal abscess model. The test organism was resistant to cefotaxime by standard methods (MIC greater than 128 micrograms/ml) but was inhibited by 1.0 microgram/ml when rat serum was presented in the medium. Cefotaxime reduced titers of bacteria within abscesses after 5 days of therapy (5.77 +/- 0.68 log10 CFU/g) in comparison with those in control animals (7.38 +/- 0.28 log10 CFU/g, p less than 0.05). Moxalactam, the in vitro activity of which was not augmented by serum, proved ineffective in the animal model. While these observations do not have direct therapeutic relevance, they offer a possible explanation for the relatively infrequent occurrence of enterococcal superinfection in patients treated with cefotaxime.

Hypercalcemia attenuates blood pressure response to epinephrine

The potent alpha and beta adrenergic actions of epinephrine are probably mediated through an increase in free intracellular calcium concentration. Despite an absence of experimental evidence, many clinicians administer epinephrine with calcium to augment its cardiovascular effects. We evaluated the effects of calcium on epinephrine's pressor response in both normal and endotoxin-treated rats by administering epinephrine to animals made hypercalcemic with calcium chloride or hypocalcemic with the calcium chelator EGTA. EPI, given in incremental doses of 10, 20 and 50 micrograms/kg, produced incremental increases in mean arterial pressure. Calcium chloride infused i.v. at a rate of 50 mg/ml/hr significantly (P less than .05) blunted (50% decrease) the hypertensive response to 50 micrograms/kg epinephrine in normal animals. In endotoxin-treated rats, calcium chloride at 50 mg/ml/hr significantly blunted the hypertensive response to 10 micrograms/kg (73% decrease), 20 micrograms/kg (62% decrease) and 50 micrograms/kg (50% decrease) epinephrine. Endotoxemia plus calcium chloride at 25 mg/ml/hr also significantly blunted (30% decrease) the hypertensive response to 50 micrograms/kg EPI. By contrast, hypocalcemia produced by EGTA (30 mg/ml/hr) had no effect on epinephrine's hypertensive effects in normal or endotoxemic rats. Since calcium chloride significantly diminishes epinephrine's hypertensive effects in both normal and endotoxin-treated rats, the clinical use of calcium chloride along with epinephrine may not have a sound experimental basis.

Mechanism of action and in vitro and in vivo activities of S-6123, a new oxazolidinone compound

The in vitro activity of S-6123, a synthetic antimicrobial compound of the new oxazolidinone series, was compared with those of other orally administered agents against 328 clinical isolates. The compound was moderately active (MICs, 16 to 64 micrograms/ml) against 90% of staphylococci, nonenterococcal streptococci, and Haemophilus influenzae, including strains resistant to beta-lactam antibiotics. S-6123 was minimally active against enterococci and facultative gram-negative bacilli. Nevertheless, the compound had significant activity in a lethal rat Escherichia coli peritonitis model at serum concentrations of one-tenth the MIC against the infecting organism. The drug demonstrated only bacteriostatic activity against susceptible organisms. Studies to define the mechanism of antibacterial action revealed that S-6123 inhibited ribosomal protein synthesis without inhibiting DNA or RNA synthesis. This compound represents a new series of antibacterial agents not related to any other antibacterial compound of natural or synthetic origin.

Free fatty acids alter calcium binding: a cause for misinterpretation of serum calcium values and hypocalcemia in critical illness

FFAs are bound with calcium on the albumin molecule. We hypothesized that changes in circulating FFA levels during critical illness altered calcium-albumin binding. We found that serum from both normal subjects and critically ill patients contained an ether-extractable factor which lowered ionized calcium concentrations and increased albumin-calcium binding. This factor was found in higher concentrations in serum from ill patients. Oleic acid and palmitic acid increased albumin-calcium binding from 2-28% in a dose-dependent manner when added in vitro to calcium-albumin solutions. Scatchard analysis demonstrated that 0.1 mM oleic acid increased the number of calcium-binding sites on the albumin molecule (from three to five sites per molecule) without altering binding affinity. A similar effect was found when we performed Scatchard analyses of ether extracts in serum from three critically ill patients (number of calcium-binding sites increased from three to six). We also found that lipid infusions (during parenteral nutrition) lowered mean serum ionized calcium values in six critically ill patients [4.6 +/- 0.2 (+/- SEM) to 4.1 +/- 0.2 mg/dL; P less than 0.05]. These data support the concept that FFAs increase calcium binding to the albumin molecule. Alterations in FFA concentrations during critical illness may contribute to the poor correlation between corrected total serum calcium and ionized calcium concentrations in critically ill patients. In addition, acute elevations in circulating FFA concentrations may contribute to hypocalcemia in patients with defects in bone calcium mobilization.

Continuous-infusion ampicillin therapy of enterococcal endocarditis in rats

Intermittent administration of ampicillin alone has resulted in high failure rates in previously described animal models of enterococcal endocarditis. We developed a rat model of enterococcal endocarditis which permits comparison of continuous intravenous infusion of ampicillin with intramuscular therapy. Continuous low-dose ampicillin infusion (450 mg/kg [body weight] per day) was compared with the same dose given intramuscularly in three divided doses and with high-dose infusion (4.5 g/kg per day) of the drug. For the infecting strain of Streptococcus faecalis, the MIC and MBC were 1 microgram/ml. Mean ampicillin levels in serum were 53.9 +/- 4.8 (peak) and less than 1 (trough), 8.7 +/- 1.4, and 244 +/- 29 micrograms/ml for intramuscular, low-dose, and high-dose regimens, respectively. Ampicillin infusion therapy significantly increased the survival rate and sterilization of blood cultures. Continuous infusions were superior to intermittent therapy in eradicating bacteremia. After 5 days of treatment, low-dose ampicillin infusion was more effective than intermittent therapy in sterilizing cardiac vegetations (P less than 0.01). Continuous-infusion therapy at either dose was significantly more effective than intramuscular injection in reducing bacterial titers in cardiac vegetations (5.4 +/- 1.0 log10 CFU/g [low dose], 4.8 +/- 0.3 log10 CFU/g [high dose], and 7.7 +/- 0.3 log10 CFU/g [intramuscular]). However, no statistically significant advantage was found for high-dose compared with low-dose ampicillin infusion in lowering bacterial titers in vegetations (P greater than 0.3).

In vitro and in vivo activity of LY 146032, a new cyclic lipopeptide antibiotic

The in vitro activity of LY 146032, a cyclic lipopeptide antibiotic belonging to the class of agents designated A21978C, was compared with those of vancomycin, cefpirome, cefotaxime, and clindamycin against selected gram-positive bacteria. The new drug inhibited all staphylococcal isolates, including methicillin-resistant strains, at concentrations of less than or equal to 1.0 microgram/ml. The activity of LY 146032 was comparable to that of vancomycin against most streptococci, but the latter demonstrated greater potency against Streptococcus faecium and penicillin-resistant strains of pneumococci and viridans group streptococci. LY 146032 was markedly less active than vancomycin against Listeria monocytogenes (MICs for 90% of strains tested, 16 and 1.0 microgram/ml, respectively). The activity of LY 146032 was enhanced as the concentration of calcium in the test medium was increased. MBCs were within eightfold of the MIC for each of 12 strains tested. In a rat model of enterococcal endocarditis, the administration of LY 146032 resulted in increased survival and a reduction in the bacterial titer within cardiac vegetations compared with untreated control animals.

Isolation rates and toxigenic potential of Clostridium difficile isolates from various patient populations

Stool specimens in various patient populations were examined to determine isolation rates of Clostridium difficile and the frequency with which this organism produces a cytopathic toxin in vitro. Clostridium difficile was isolated from 13 of 45 healthy neonates who had never received antimicrobials and the cytotoxin was detected in 12. With 23 healthy children aged 4 to 24 mo the organism was recovered from 2 children and the cytotoxin was detected in 1. Neither the organism nor the cytotoxin was found in specimens from healthy adults who denied antimicrobial usage during the prior 4 wk. Clostridium difficile was recovered from 12 of 56 adults receiving antimicrobials without diarrhea, but only one specimen yielded the cytotoxin. Both the cytotoxin and the organism were found in stools from most patients with antibiotic-associated colitis. Concentrations of Clostridium difficile, when present, were similar in all patient populations. Broth cultures of 165 isolates of Clostridium difficile showed all strains, but two produced the cytotoxin in vitro. However, the concentration of the toxin was substantially higher with strains recovered from patients with positive toxin assays. These observations indicate that neonates are often asymptomatic carriers of both Clostridium difficile and its cytotoxin. In adults, gastrointestinal symptoms correlated best with results of tissue culture assays and with toxigenic potential of the strains isolated.

Antibacterial properties of lidocaine

The inhibitory effect of lidocaine and lidocaine plus methylparaben as a preservative was studied with 25 strains of bacteria. The tested strains were mixed with each topical anesthetic preparation, and quantitative cultures were performed on aspirates at 0, 30, 60, and 120 minutes. Results were compared to counts obtained in a lactated Ringer's solution, which were sampled at the same intervals. Lidocaine (1 percent solution) reduced quantitative counts after 120 minutes of contact by over one log for only six of the 25 strains tested. Lidocaine plus methylparaben reduced quantitative counts to a somewhat greater extent; nevertheless, all strains except Bacteroides melaninogenicus were recovered in relatively high concentrations at each sampling interval. Numerous previous studies have shown that topical anesthetic agents are toxic to bacteria. The results of this study show that this toxic effect is not sufficiently severe to prevent the recovery of most pathogens of the lower respiratory tract in bronchoscopic aspirates.

Quantitative tracheal bacteriologic and cytologic studies in patients with long-term tracheostomies

Quantitative aerobic and anaerobic cultures were performed on 28 tracheal aspirates from 16 clinically stable patients with tracheostomies. There were an average of six isolates per specimen, and the mean bacterial concentration was 106.9 organisms per milliliter. The numerically dominant bacteria were aerobic and facultative gramnegative bacilli. Anaerobic bacteria were recovered from just nine specimens (32 percent); and, when present, these organisms were found in relatively low concentrations. Repeat cultures obtained 30 to 60 days later from the same patients showed substantial changes in flora, but the numerically dominant species tended to persist. Cultures of saliva and throat swabs collected at the time of tracheal aspiration showed that there was little correlation between the bacteriologic findings from the upper and lower airways. Cytologic studies indicated a mean of 12,900 cells per cubic millimeter of tracheal aspirate, with polymorphonuclear leukocytes being the predominant forms. No correlation could be found between the concentrations of polymorphonuclear leukocytes and quantitative bacterial counts. These studies indicate that tracheal aspirates from patients with stable tracheostomies harbor a complex, predominantly aerobic flora which is subject to change and bears little relationship to the flora of the adjacent upper airways. Our results also suggest that neither quantitative bacterial cultures nor cytologic analysis of these specimens would be helpful in distinguishing colonization from overt infection requiring antibiotic treatment.