932 Delivering Excellence in Orthopaedic Training - A Five Year Qualitative Study of Characteristics Valued by Trainees Voting for Trainer of The Year

Background

Previous studies have described attributes of successful trainers. Dean et al’s (2017) systematic analysis found 12 commonly cited positive characteristics in medical literature. This paper and Nisar et al’s (2011) study which had a more exhaustive list of desirable qualities in surgical trainers formed the basis of our thematic analysis to identify trainer characteristics/behaviours valued by trainees on an orthopaedic training programme.

Method

We evaluated qualitative data from votes on the North West Thames rotation for Trainer of the Year over a 5-year period (2016-2020). We applied thematic analysis to identify 15 characteristics commonly cited by trainees in their nominations and logged how frequently each characteristic was raised.

Results

The five most popular qualities possessed by nominees are 1) prioritisation of training needs and endeavouring to create more training opportunities for trainees 2) being a source of support 3) willingness to allow trainees to operate 4) setting and facilitating the achievement of educational goals/targets 5) providing appropriate levels of supervision. All 15 valued characteristics and their frequency of mention are listed in the table presented.

Conclusions

To the best of our knowledge this is the only study which focuses exclusively on desirable qualities orthopaedic specialist trainees’ value in their trainers. ‘Advocating for trainees’ is a valued quality, also highlighted in ASIT’s 2018 analysis of the Silver Scalpel Award nominations, which is not otherwise well described in the literature. We hope our work will allow aspiring orthopaedic trainers insight into what trainee’s value most in a surgical mentor.

0622 In-Depth Surveillance of Central Sleep Apnea in Patients with Stable Heart Failure

Introduction

Central sleep apnea (CSA) is unique sleep breathing phenotype in patients with advanced chronic heart failure (HF) and portend poor prognosis. The prevalence of CSA in HF patients under contemporary therapy is uncertain.

Methods

We reviewed consecutive HF patients on optimal medical therapy who underwent clinically indicated diagnostic in-lab polysomnography at a single academic center. Age, sex and BMI matched patients without HF were selected from sleep clinic as a control. Patients with atrial fibrillation were excluded from this study. Apnea subtypes were determined after careful scoring and confirmation by sleep physicians. ‘Any CSA’ was defined by central apnea index (CAI) >5 and >1/hr. ‘True CSA’ was defined if met both CAI≥5/hr and > obstructive apnea index (OAI). Obstructive sleep apnea (OSA) was defined if apnea hypopnea index >15 and OAI>CAI. Multivariate analysis was performed using logistic regression adjusting for age, sex, HF and systolic dysfunction as appropriate.

Results

In patients with HF (N=95, mean age 59, female: 50%), CSA was low and was comparable to control group (N=94) (HF vs. Non-HF; CSA: 5.3 vs. 4.3%, P=NS; Any CSA 14.7 vs. 17%, P=NS). Only 3 patients with HF had true CSA. In contrast, OSA was common in both groups regardless of obesity status (52.3 vs. 55.3%). In patients with HF, Cheyne Stokes respiration was more frequent in patients with Any CSA vs. without Any CSA (13.3 vs. 3.8%, p=0.04). In multivariate analysis, presence of OSA, but not HF, was associated with Any CSA in entire cohort (Any CSA OR: 3.1 [1.3, 8.1], p=0.02). In patients with HF, male sex was associated with Any CSA (OR: 5.3 [1.1, 40.8], p=0.05). Exclusion of patients with high BMI did not change the results.

Conclusion

CSA was rare in patients with stable HF on contemporary optimal medical therapy.

Support

None

Venous flaps for coverage of traumatic soft tissue defects of the hand: a systematic review

A PRISMA-guided systematic review was performed of all published cases that detail the use of venous flaps for soft tissue reconstruction of the hand following trauma. Outcome measures examined included flap survival rates, venous congestion, and return to theatre. Database searches were performed on Medline, Embase, AHMED, CINAHL. A total of 381 articles were identified. Data were extracted from 45 articles that met inclusion criteria. A total of 756 flaps were described and their data analysed. A total of 75% of flaps were arterialized and 25% were pure venous flaps. There was no difference in survival rate for arterialized or pure venous flaps. Unplanned return to theatre occurred in 5.3% due to flap compromise or necrosis. Early venous congestion was present in 60% of cases. Total early failure requiring re-operation occurred in 19 flaps (2.5%) of cases. Venous flaps offer a versatile and well-tolerated reconstructive option. Early venous congestion is common, but can be managed non-operatively.

LEVEL OF EVIDENCE

II.

Segond fracture in an adult is not pathognomonic for ACL injury

The Segond fracture is an avulsion fracture of the lateral tibial plateau and is considered pathognomonic for anterior cruciate ligament (ACL) injury. A case of a Segond fracture occurring with a clinically, radiologically and arthroscopically intact ACL is presented. This was associated with a serious injury to the posterolateral corner requiring surgical reconstruction. Relevant literature is discussed, and the suggestion is made that, whilst an ACL rupture may be the most commonly noted soft tissue component associated with a Segond fracture, the clinician should have a high level of suspicion for other serious soft tissue injuries. Level of evidence V.

Persistent Isolation of an Unusual Pseudomonas Species From a Phenolic Disinfectant System

A well-characterized unusual Pseudomonas species contaminated the piped disinfectant system of a newly-opened laminar air flow intensive care facility. This organism was frequently isolated (104-106 cfu/ml) from phenolic diluted 1:256 in the system, and could also be recovered (0.01-0.2 cfu/ml) from undiluted phenolic. During the 20-month period when this unusual Pseudomonas was present, none of the severely compromised, granulocytopenic oncology patients treated in the intensive care facility were either colonized or infected with this Pseudomonas sp. Eradication of the organism from the system proved difficult and was accomplished by removing a contaminated reservoir of diluted phenolic disinfectant followed by transient cleansing of the system with very high concentrations (84,000 ppm) of chlorine. This experience demonstrates that phenolics should be added to the list of disinfectants which can harbor Pseudomonas spp. in the clinical setting.

Systematic review of small bowel diaphragm disease requiring surgery

AIM

To perform a systematic review of all cases of small bowel diaphragm disease requiring surgery. Small bowel diaphragm disease is a rare complication of small bowel enteropathy secondary to the use of non-steroidal anti-inflammatory drugs (NSAIDs). The objective was to determine the presenting symptoms, duration of NSAID use, mode of diagnosis and type of surgery associated with cases of small bowel diaphragm disease requiring surgery.

METHOD

A comprehensive search of the world literature between January 1980 and December 2010 was undertaken. The search terms 'diaphragm disease' and 'mucosal diaphragm disease' in combination with the terms 'surgery', 'intestine' or 'small bowel' were used. All cases of small bowel diaphragm disease requiring surgery in adult patients within the the last 30 years were included. Data including age, gender, mode of presentation, NSAID use, mode of diagnosis, form of surgery, affected area of small bowel and mortality were recorded and analysed.

RESULTS

There were 55 cases of small bowel diaphragm disease requiring surgery (31F:18M) with a median age of 69 years. NSAID use occurred in 44 cases and the mean duration of NSAID use was 7 years. The most common presentation was with anaemia in combination with obstructive symptoms. The diagnosis was established by a laparotomy in 51% of cases followed by capsule endoscopy in 25% of cases. Operations performed included small bowel resection (56), combined resection and strictureplasty (three), strictureplasty (one) and hemicolectomy (two). There was only one death.

CONCLUSION

Small bowel diaphragm disease presenting as a surgical emergency is likely to become more common due to the increased use of NSAIDs. A history of NSAID use in patients with iron deficiency anaemia or obstructive symptoms should lead to a high index of suspicion for this condition and should be preoperatively investigated.

Views regarding the provision of prehospital critical care in the UK

AIMS

There is a lack of consensus regarding the role for critical care in the prehospital environment in the UK. It was hypothesised that this related to differences in views and understanding among opinion leaders within influential prehospital care organisations.

METHODS

A 38-item survey was developed by an established paramedic-physician prehospital critical care service. The survey was distributed to individuals in senior positions within seven organisations that have a major influence on UK prehospital services. Analysis comprised a description of the distribution of results, assessment of the level of agreement with each statement by professional background and current involvement in prehospital critical care and evaluation of the overall consistency of responses. Free-text comments were invited to illustrate the reasoning behind each response.

RESULTS

There were 32 respondents. The estimated response rate was 40%. The consistency of the questionnaire responses was very high. Overall, all individuals agreed with most of the statements. Paramedic respondents were more likely to disagree with statements that suggested that critical care involved interventions that exceed the current capability of the NHS ambulance service (p<0.05). Free-text comments revealed wide differences of opinion.

CONCLUSION

Although there appears to be broad agreement among opinion leaders regarding the concepts underpinning existing prehospital critical care services, areas of contention are highlighted that may help explain the current lack of consensus. Cooperative efforts to assess the current demand and clinical evidence would assist in the creation of a joint consensus and allow effective future planning for the provision of prehospital critical care throughout the UK.

Prevalence of latent, neuropathogenic equine herpesvirus-1 in the Thoroughbred broodmare population of central Kentucky

REASON FOR PERFORMING STUDY

An emerging problem of equine herpesvirus-1 (EHV-1) infection in horses in the USA is a high-mortality myeloencephalopathy that commonly occurs where large numbers of horses are stabled. EHV-1 isolates recovered from recent neurological outbreaks represent a mutant virus strain that possesses enhanced neuropathogenicity. A central question of EHV-1 myeloencephalopathy is the latency carriage rate for these mutants of EHV-1 in USA horse populations.

OBJECTIVE

To estimate the prevalence of neuropathogenic strains of EHV-1 as latent infections in the Thoroughbred broodmare population of central Kentucky.

METHODS

Submandibular lymph nodes (SMLN) were collected during post mortem examination of 132 Thoroughbred broodmares. Total DNA purified from SMLN tissue was tested for the presence of latent EHV-1 DNA by an ultrasensitive magnetic bead-based, sequence-capture, nested PCR method. Differentiation of active from latent infections by EHV-1 was achieved by detection of transcripts of EHV-1 glycoprotein B by reverse transcription PCR.

RESULTS

Latent EHV-1 DNA was detected in the SMLN tissues of 71 (54%) of the 132 mares submitted for necropsy. Thirteen (18%) of the 71 latently infected horses harboured the neuropathogenic biovar of EHV-1. Of the 13 horses latently infected with an ORF30 mutant strain of EHV-1, 11 also carried a latent, wild-type strain of the virus in their SMLN tissues.

CONCLUSIONS

Neuropathogenic strains of EHV-1 have established a significant presence in the Thoroughbred broodmare population of central Kentucky as latently infected carrier horses. The data also indicate that a highly sensitive DNA detection method is required to identify many instances of EHV-1 latency.

POTENTIAL RELEVANCE

The presence of a relatively large biological reservoir of latent, neuropathogenic EHV-1 has the potential for posing emerging equine health and economic threats to the future prosperity of the USA horse industry.

Omnifit acetabular component: a solution to preventing and treating dislocation

PURPOSE

To assess short- to medium-term outcome of the Omnifit constrained acetabular component in preventing dislocation in at-risk patients after total hip arthroplasty (THA).

METHODS

81 patients (mean age, 77 years) underwent either primary or revision THA with an Omnifit constrained acetabular component and were followed up clinically and radiologically for a mean period of 24 months.

RESULTS

There was one dislocation and one revision for avulsion of the acetabulum. The remaining prostheses remained well fixed.

CONCLUSIONS

In the short- to medium-term, the Omnifit constrained acetabular component is effective in preventing primary and recurrent dislocation in at-risk patients. Long-term follow-up is needed to assess whether good fixation is maintained. The Omnifit acetabular cup is recommended for elderly patients with limited life expectancy and functional demands.

How accurate and reliable are doctors in estimating fracture angulation?

This study assessed the accuracy of doctors in estimating fracture angulation. Radiographs of fractured wrist and forearm of varying angulations were shown to all grades of doctors in the speciality of trauma and orthopaedics. They were asked to estimate the angulation at the fracture site without using a goniometer. The estimates were analysed for accuracy and variability. This study showed that doctors have a mean error of 8-9 degrees and had poor agreement with themselves and others. We recommend the use of a goniometer to assess fracture angulation.

Williams syndrome and happiness

Williams syndrome is a genetic disorder resulting in a variety of medical and developmental features, one of which is a frequent outward presentation of substantial happiness. In this paper we describe the unique expression of happiness in people with Williams syndrome, with several anecdotes and a frame by frame conversational analysis. We then discuss this happiness in the context of other dimensions of the impact of Williams syndrome, especially anxiety. We conclude with a discussion of the role of genetics in emotions.

Contribution of diet, tumour volume and patient-related factors to weight loss in patients with colorectal liver metastases

BACKGROUND

One of the difficulties in assessing the contribution of tumour-related factors to cancer cachexia is measurement of the extent of disease where dissemination to multiple organ sites has occurred.

METHODS

In this study the extent of tumour (both tumour volume and increase in marker levels), diet and patient-related factors (appetite, metabolic hormones, immune activation, liver function and quality of life) were compared in patients with colorectal liver metastases who had lost at least 1 kg in body-weight (weight loss) and patients who had not lost 1 kg in body weight (stable weight) during the preceding month.

RESULTS

Forty patients (22 men; 14 with weight loss) were studied. Liver metastasis volume was significantly greater in patients who lost weight than in those whose weight was stable (median (interquartile range) 1179 (245-1517) versus 119 (23-523) ml; P = 0.003). The prevalence of patients with raised levels of serum immune products was significantly greater in the weight loss group for soluble interleukin (IL) 2 receptor alpha (sIL2ralpha) (P = 0.03) and IL-6 (P = 0.05), but not for soluble tumour necrosis factor receptor 1 (sTNFr1) or neopterin. There were significant correlations between serum C-reactive protein and sIL2ralpha (rs = 0.68, P < 0.0001) and IL-6 (rs = 0.46, P = 0.008) but not sTNFr1 or neopterin levels. Significant differences in appetite, nausea, diet, energy intake, liver function tests and serum levels of metabolic hormones were not detected.

CONCLUSION

Weight loss in patients with colorectal liver metastases was not explained by changes in diet, quality of life, or hormones, but activation of the innate and incomplete activation of the acquired immune systems may be involved. Agents that attenuate either the acute-phase inflammatory response or T lymphocyte IL-2 receptor upregulation might reduce weight loss in patients with metastatic disease.

Acute deterioration of renal function associated with enteric hyperoxaluria

Enteric hyperoxaluria due to malabsorption syndromes has been well documented to cause renal calculi and chronic tubulointerstitial renal damage. Rarely, in the setting of intestinal bypass operations for morbid obesity, enteric hyperoxaluria has produced acute renal failure. We report two patients who suffered acute deterioration of renal function associated with increased intestinal absorption and renal excretion of oxalate associated with steatorrhea. One patient had a large portion of his small bowel resected many years prior to the onset of the renal failure and the second patient had chronic pancreatitis causing steatorrhea. Both patients had renal biopsy documentation of the acute nature of the tubular damage produced by oxalate deposition. The mechanisms of their deterioration of renal function may relate to sudden increases in steatorrhea in association with episodes of volume depletion. Enteric hyperoxaluria may be an easily overlooked and potentially preventable etiology of acute renal dysfunction.

Quantitative calibration and use of DNA probes for investigating chromosome abnormalities in the Prader-Willi syndrome

Ten genomic DNA probes, subcloned from inserts derived from a phage library constructed from the DNA of flow-sorted chromosomes, have now been mapped to locations within 15q11-15q13. By dosage blotting and densitometry, 5 of these probes map to the 15q11.2-15q12 segment missing in one 15 chromosome of a Prader-Willi syndrome (PWS) patient with a prominent cytological deletion. A sixth probe most likely maps to the same region. The other 4 probes map outside of this segment but within 15q11-15q13. Several of the 15q11.2-15q12 probes, and a cDNA probe homologous to one, have been used to test the DNA from 8 patients exhibiting a wide range of the clinical manifestations expected for PWS patients. DNA deletion was observed in all 3 patients with cytological 15q1 deletions as well as in a patient with an unbalanced (Y;15) translocation. DNA from 1 PWS patient with an unbalanced (5;15) translocation and an inverted duplication of the short arm and proximal long arm of 15 showed at least 1 and possibly 2 extra copies of each genomic probe tested. In the other 3 patients with no cytological deletions, no DNA deletions were found. Thus, the molecular probes described can be used in most PWS patients to analyze the region of proximal 15q implicated in this syndrome.

Restriction fragment length polymorphisms within proximal 15q and their use in molecular cytogenetics and the Prader-Willi syndrome

Restriction fragment length polymorphisms (RFLPs) are described in detail for 6 DNA probes (D15S9-13, D15S18) that localize to the proximal long arm of human chromosome 15 (15q11-15q13: this report and Tantravahi et al., Am. J. Med. Genet. 33:78-87. Multiple RFLPs are detected by the probe that identifies locus D15S13, and these RFLPs are shown by genomic mapping to result from a nearby insertion or deletion of 1.8 kilobases (kb) of DNA. This set of RFLPs detected by proximal 15q probes can be used for studies on the Prader-Willi syndrome (PWS) and on mentally retarded individuals with a supernumerary inv dup(15) chromosome. Five of the polymorphic loci (D15S9-13) map to the region implicated in the cause of the PWS (15q11.2-15q12). Each of 4 families tested with these probes, as well as an additional "PWS-like" patient, was informative by RFLP analysis. The two PWS deletions studied, which occurred de novo, were inherited from the chromosome 15 provided by the father. By contrast, the 2 inv dup(15) chromosomes analyzed were of maternal origin. The use of RFLPs can also simplify the molecular determination of copy number in chromosomal aneuploidy, as exemplified by analysis of individuals with the PWS and a deletion, patients with an inv dup(15), and one patient with a more complex rearrangement involving chromosome 15. Our studies demonstrate the application of DNA probes for both molecular cytogenetic studies on this chromosome region and the development of diagnostic molecular markers to aid early clinical diagnosis of the PWS.

A repressor heterodimer binds to a chimeric operator

Replacement of the solvent-exposed residues of the DNA recognition helix of the 434 repressor with the corresponding residues of the P22 repressor generates a hybrid protein, 434R[alpha 3(P22R)], which binds specifically to P22 operators. We show here that a new DNA-binding specificity is generated by combining 434 and 434R[alpha 3(P22R)] repressor monomers to form a heterodimer. The heterodimer specifically recognizes a chimeric P22/434 operator that lacks two-fold rotational symmetry.

Bacillus infections in patients with cancer

Eighteen febrile patients experienced 24 episodes of Bacillus bacteremias from January 1978 to June 1986. Bacillus species isolated included Bacillus cereus (eight cases), Bacillus circulans (three), Bacillus subtilis (two), Bacillus pumilus (two), Bacillus licheniformis (one), Bacillus sphaericus (one), Bacillus coagulans (one), and six that could not be speciated. Fifteen patients had lymphoma or leukemia and three had breast cancer. Nine patients were neutropenic (polymorphonuclear neutrophil count, less than 1.0 x 10(9)/L), seven patients had a Hickman catheter in place, and 14 had recently received chemotherapy. Twelve of the bacteremic episodes were clinically significant, and four of these 12 involved Hickman catheters. Catheter removal was ultimately necessary in all four patients. Scanning and transmission electron microscopy was performed on one of the removed Hickman catheters and showed Bacillus organisms embedded in a biofilm composed of gram-positive cocci and glycocalyx. Bacillus species were uniformly susceptible to vancomycin, imipenem, and aminoglycosides, with penicillin susceptibilities being variable. Bacillus appears to be another gram-positive organism now being recognized as a bacterial pathogen for compromised hosts. When such infections involve long-term indwelling venous access devices, treatment should include immediate catheter removal as well as antibiotic therapy.

Clinical heterogeneity associated with deletions in the long arm of chromosome 15: report of 3 new cases and their possible genetic significance

Deletions, duplications, and rearrangements of the long arm of chromosome 15 are frequently associated with the clinical diagnosis of the Prader-Willi syndrome. However, a number of other clinical entities have also been associated with similar, if not identical, cytogenetic defects, arguing for clinical heterogeneity associated with abnormalities in this region of chromosome 15. We present 3 patients who all appear to have deletions in 15q11-15q12, such as described for many patients with Prader-Willi syndrome; however, none of these patients has classical clinical features of the Prader-Willi syndrome. The first patient is a child with Williams syndrome, the second, Angelman (Happy Puppet) syndrome, and the third is a child with hypotonia of infancy, obesity, and developmental delay, but who does not meet specific diagnostic criteria for the Prader-Willi syndrome. It is proposed that different molecular abnormalities involving specific points or segments along the long arm of chromosome 15 might account for the clinical diversity seen among these and other patients.

Complementary medicine and the general practitioner

The attitudes to complementary medicine of a random sample of general practitioners in Avon were assessed. A questionnaire was sent to 200 general practitioners, of whom 145 responded. The treatments studied were acupuncture, homoeopathy, herbal medicine, spinal manipulation, faith healing, and hypnosis. Of the 145 general practitioners, 55 (38%) had received some training in complementary medicine and 22 (15%) wished to arrange training. Overall, general practitioners knew little about the techniques of complementary medicine. Despite this 86 doctors (59%) thought that the complementary techniques being assessed were useful to their patients: 110 (76%) had referred patients for this type of treatment over the past year to medically qualified colleagues and 104 (72%) had referred patients to non-medically qualified practitioners. Most (93%) of those who responded believed that complementary practitioners needed statutory regulation; only 3% thought that they should be banned. The method of regulation most favoured was through a central and independent national body. General practitioners' views about complementary techniques were most influenced (in a positive manner) by observed benefits to their patients (41%) and personal or family experience of benefit (38%). The results of the study show a surprisingly high interest in complementary medicine among general practitioners in the Avon area.

Antibiotic synergism and response in gram-negative bacteremia in granulocytopenic cancer patients

To determine whether antimicrobial synergism affects the outcome of gram-negative bacteremia among profoundly (less than 100/microliter) neutropenic cancer patients, the clinical courses of 75 such patients who received empiric therapy with combination, broad-spectrum antibiotics were analyzed. Twenty-nine of 34 (85 percent) patients whose granulocyte count increased to more than 100/microliter during therapy improved, whereas only 12 of 41 (29 percent) patients with no increase in granulocyte count showed improvement (p = 0.0002). The critical group for further analysis was, therefore, those patients with persistent, profound granulocytopenia. Among these 41 patients, synergism was associated with a substantially better response rate: eight of 18 (44 percent) improved compared with none of 13 in whom synergism was not detected (p = 0.005); presence or absence of synergism could not be assessed for the pathogens isolated from the remaining 10 patients because the organisms were exquisitely susceptible to one of the two antibiotics used. Further evaluation of these persistently neutropenic patients indicated that synergism appeared critical even when the pathogen was susceptible to both antibiotics. Thus, seven of 11 (64 percent) showed response when the two drugs were synergistic in activity, compared with none of six when synergism was not present (p = 0.01). These data again demonstrate the importance of granulocyte recovery to patient response and further indicate that synergistic combinations of antibiotics are indicated for cancer patients with gram-negative bacteremia and persistent, profound granulocytopenia.

Violence on television and imitative behavior: impact on parenting practices

In the past 30 years, four federal government commissions have reported on the relationship between television violence and aggressive behavior. The latest report concluded categorically that there is a causal relationship between television violence and aggressive behavior. Two infants were seen at an emergency room as a direct consequence of their socially isolated single mothers seeing a particular made-for-television movie. In one case, the infant died as a possible result of a parent imitating an act of child abuse; in the other case, early medical intervention precluded possible tragedy. These cases illustrate another way in which children may be victimized by violence on television; namely, by parents imitating inappropriate parental behavior. The origins of imitative behavior are discussed with specific reference to the impact on vulnerable parents. The concept of media-influenced parenting behavior is presented and implications for physicians are discussed.

Moxalactam and piperacillin: a study of in vitro characteristics and pharmacokinetics in cancer patients

We evaluated the microbiologic characteristics including MIC determinations, synergy plate assays and serum bactericidal activity for two regimens being examined as empiric antibiotic therapy for febrile granulocytopenic cancer patients. The regimens consisted of moxalactam (4 g.i.v. q12h) plus piperacillin (75 mg/kg i.v. q6h) or moxalactam (as above) plus amikacin (levels adjusted to one hour post-infusion levels of 25 mg/l and troughs of 6-8 mg/l). Detailed pharmacokinetics were ascertained for the beta lactams. All drugs were active against a panel of 11 strains each of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. The pharmacokinetic profile showed serum levels sufficient to provide good antimicrobial activity throughout the dosing interval. Both regimens displayed synergistic or partially synergistic activity in the main for the test organisms; moxalactam plus piperacillin produced good results against S. aureus and P. aeruginosa. In the serum bactericidal assays, the moxalactam-piperacillin combination produced significantly higher mean titers at both peak and trough when compared to the moxalactam-amikacin regimen. This may be because moxalactam acts as a beta lactamase inhibitor for both staphylococcal beta lactamase, as well as the Sabath-Abraham Id type beta lactamase carried by P. aeruginosa (among others). Moxalactam-piperacillin deserves extensive evaluation as empiric therapy for the febrile neutropenic cancer patients.

Atmosphere behavior in gas-closed mouse-algal systems: an experimental and modelling study

Concepts of biologically-based regenerative life support systems anticipate the use of photosynthetic organisms for air revitalization. However, mismatches in the rates of production and uptake of oxygen or carbon dioxide between the crew and the plants will lead to an accumulation or depletion of these gases beyond tolerable limits. One method for correcting these atmospheric changes is to use physiochemical devices. This would conflict with the constraint of minimal size and weight imposed upon the successful development of a competitive bioregenerative system. An alternate control strategy is based upon reducing the gas exchange mismatch by manipulation of those environmental parameters known to affect plant or algae gas exchange ratios. We have initiated a research program using a dual approach of mathematical modelling and laboratory experimentation aimed at examining the gas exchange characteristics of artificial animal/plant systems closed to the ambient atmosphere. Our goal is to develop control techniques and management strategies for maintaining the atmospheric levels of carbon dioxide and oxygen at physiological levels. A mathematical model simulating the atmospheric behavior in these systems has been developed and an experimental gas-closed system has been constructed. These will be described and preliminary results will be presented.