Implementing a cirrhosis order set in a tertiary healthcare system: a theory-informed formative evaluation

BACKGROUND

Standardized order sets are a means of increasing adherence to clinical practice guidelines and improving the quality of patient care. Implementation of novel quality improvement initiatives like order sets can be challenging. Before the COVID-19 pandemic, we conducted a formative evaluation to understand healthcare providers' perspectives on implementing clinical changes and the individual, collective and organizational contextual factors that might impact implementation at eight hospital sites in Alberta, Canada.

METHODS

We utilized concepts from the Consolidated Framework for Implementation Research (CFIR) and Normalisation Process Theory (NPT) to understand the context, past implementation experiences, and perceptions of the cirrhosis order set. Eight focus groups were held with healthcare professionals caring for patients with cirrhosis. Data were coded deductively using relevant constructs of NPT and CFIR. A total of 54 healthcare professionals, including physicians, nurses, nurse practitioners, social workers and pharmacists and a physiotherapist, participated in the focus groups.

RESULTS

Key findings revealed that participants recognized the value of the cirrhosis order set and its potential to improve the quality of care. Participants highlighted potential implementation challenges, including multiple competing quality improvement initiatives, feelings of burnout, lack of communication between healthcare provider groups, and a lack of dedicated resources to support implementation.

CONCLUSIONS

Implementing a complex improvement initiative across clinician groups and acute care sites presents challenges. This work yielded insights into the significant influence of past implementation of similar interventions and highlighted the importance of communication between clinician groups and resources to support implementation. However, by using multiple theoretical lenses to illuminate what and how contextual and social processes will influence uptake, we can better anticipate challenges during the implementation process.

Mouse models of NADK2 deficiency analyzed for metabolic and gene expression changes to elucidate pathophysiology

NADK2 encodes the mitochondrial form of NAD Kinase, which phosphorylates nicotinamide adenine dinucleotide (NAD). Rare recessive mutations in human NADK2 are associated with a syndromic neurological mitochondrial disease that includes metabolic changes such as hyperlysinemia and 2,4 dienoyl CoA reductase (DECR) deficiency. However, the full pathophysiology resulting from NADK2 deficiency is not known. Here we describe two chemically-induced mouse mutations in Nadk2, S326L and S330P, which cause a severe neuromuscular disease and shorten lifespan. The S330P allele was characterized in detail and shown to have marked denervation of neuromuscular junctions by 5 weeks of age and muscle atrophy by 11 weeks of age. Cerebellar Purkinje cells also showed progressive degeneration in this model. Transcriptome profiling on brain and muscle was performed at early and late disease stages. In addition, metabolomic profiling was performed on brain, muscle, liver, and spinal cord at the same ages, and plasma at 5 weeks. Combined transcriptomic and metabolomic analyses identified hyperlysinemia, DECR deficiency, and generalized metabolic dysfunction in Nadk2 mutant mice, indicating relevance to the human disease. We compared findings from the Nadk model to equivalent RNAseq and metabolomic datasets from a mouse model of infantile neuroaxonal dystrophy, caused by recessive mutations in Pla2g6. This enabled us to identify disrupted biological processes that are common between these mouse models of neurological disease, as well as those processes that are gene-specific. These findings improve our understanding of the pathophysiology of neuromuscular diseases, and describe mouse models that will be useful for future preclinical studies.

Comparison of a Positive Deviant Inquiry with a Case-Control Study to Identify Factors Associated with Nutritional Status among Afghan Refugee Children in Pakistan

We compared the positive deviance (PD) approach in Save the Children's field guide with a case-control study (CCS) to identify behaviors associated with good nutritional status in Afghan refugee children 6 to 24 months of age in the Northwest Frontier Province (NWFP), Pakistan. The positive deviance inquiry (PDI), utilizing observations and interviews with mothers, fathers, and secondary caregivers in eight households, identified 12 feeding, caring, and health-seeking behaviors that were not widely practiced. The CCS, using the same selection criteria and content as the PDI with 50 mother-child pairs not in the PDI, yielded six significant associations with good nutritional status. Both the PDI and CCS detected feeding behaviors. The PDI alone identified complex phenomena (active feeding and maternal affect). The CCS alone confirmed the beneficial use of health services. The PD approach was an affordable, participatory, and valid method to identify feeding behaviors and other factors associated with good nutrition in this context.

Exogenous hepatitis B virus envelope proteins induce endoplasmic reticulum stress: involvement of cannabinoid axis in liver cancer cells

HBV represents the most common chronic viral infection and major cause of hepatocellular carcinoma (HCC), although its exact role in liver tumorigenesis is unclear. Massive storage of the small (SHBs), middle (MHBs) and large surface (LHBs) HBV envelope proteins leads to cell stress and sustained inflammatory responses. Cannabinoid (CB) system is involved in the pathogenesis of liver diseases, stimulating acute and chronic inflammation, liver damage and fibrogenesis; it triggers endoplasmic reticulum (ER) stress response. The aim of our work was to investigate the activation of ER stress pathway after ectopic HBV envelope proteins expression, in liver cancer cells, and the role exerted by CB receptors. PCR, immunofluorescence and western blotting showed that exogenous LHBs and MHBs induce a clear ER stress response in Huh-7 cells expressing CB1 receptor. Up-regulation of the chaperone BiP/GRP78 (Binding Immunoglobulin Protein/Glucose-Regulated Protein 78) and of the transcription factor CHOP/GADD153 (C/EBP Homologous Protein/Growth Arrest and DNA Damage inducible gene 153), phosphorylation of PERK (PKR-like ER Kinase) and eIF2α (Eukaryotic Initiation Factor 2α) and splicing of XBP1 (X-box binding protein 1) was observed. CB1-/- HepG2 cells did not show any ER stress activation. Inhibition of CB1 receptor counteracted BiP expression in transfected Huh-7 and in HBV+ PLC/PRF/5 cells; whereas no effect was observed in HBV- HLF cells. These results suggest that HBV envelope proteins are able to induce the ER stress pathway. CB1 expression is directly correlated with ER stress function. Further investigations are needed to clarify the involvement of cannabinoid in HCC progression after HBV infection.

Preclinical Testing of a Novel Thin Film Nitinol Flow-Diversion Stent in a Rabbit Elastase Aneurysm Model

BACKGROUND AND PURPOSE

Thin film nitinol can be processed to produce a thin microporous sheet with a low percentage of metal coverage (<20%) and high pore attenuation (∼70 pores/mm(2)) for flow diversion. We present in vivo results from the treatment of experimental rabbit aneurysms by using a thin film nitinol-based flow-diversion device.

MATERIALS AND METHODS

Nineteen aneurysms in the rabbit elastase aneurysm model were treated with a single thin film nitinol flow diverter. Devices were also placed over 17 lumbar arteries to model perianeurysmal branch arteries of the intracranial circulation. Angiography was performed at 2 weeks (n = 7), 1 month (n = 8), and 3 months (n = 4) immediately before sacrifice. Aneurysm occlusion was graded on a 3-point scale (grade I, complete occlusion; grade II, near-complete occlusion; grade III, incomplete occlusion). Toluidine blue staining was used for histologic evaluation. En face CD31 immunofluorescent staining was performed to quantify neck endothelialization.

RESULTS

Markedly reduced intra-aneurysmal flow was observed on angiography immediately after device placement in all aneurysms. Grade I or II occlusion was noted in 4 (57%) aneurysms at 2-week, in 6 (75%) aneurysms at 4-week, and in 3 (75%) aneurysms at 12-week follow-up. All 17 lumbar arteries were patent. CD31 staining showed that 75% ± 16% of the aneurysm neck region was endothelialized. Histopathology demonstrated incorporation of the thin film nitinol flow diverter into the vessel wall and no evidence of excessive neointimal hyperplasia.

CONCLUSIONS

In this rabbit model, the thin film nitinol flow diverter achieved high rates of aneurysm occlusion and promoted tissue in-growth and aneurysm neck healing, even early after implantation.

Differential Gene Expression in Coiled versus Flow-Diverter-Treated Aneurysms: RNA Sequencing Analysis in a Rabbit Aneurysm Model

BACKGROUND AND PURPOSE

The biologic mechanisms leading to aneurysm healing or rare complications such as delayed aneurysm ruptures after flow-diverter placement remain poorly understood. We used RNA sequencing following implantation of coils or flow diverters in elastase aneurysms in rabbits to identify genes and pathways of potential interest.

MATERIALS AND METHODS

Aneurysms were treated with coils (n = 5) or flow diverters (n = 4) or were left untreated for controls (n = 6). Messenger RNA was isolated from the aneurysms at 4 weeks following treatment. RNA samples were processed by using RNA-sequencing technology and were analyzed by using the Ingenuity Pathway Analysis tool.

RESULTS

With RNA sequencing for coiled versus untreated aneurysms, 464/9990 genes (4.6%) were differentially expressed (58 down-regulated, 406 up-regulated). When we compared flow-diverter versus untreated aneurysms, 177/10,041 (1.8%) genes were differentially expressed (8 down-regulated, 169 up-regulated). When we compared flow-diverter versus coiled aneurysms, 13/9982 (0.13%) genes were differentially expressed (8 down-regulated, 5 up-regulated). Keratin 8 was overexpressed in flow diverters versus coils. This molecule may potentially play a critical role in delayed ruptures due to plasmin production. We identified overregulation of apelin in flow diverters, supporting the preponderance of endothelialization, whereas we found overexpression of molecules implicated in wound healing (dectin 1 and hedgehog interacting protein) for coiled aneurysms. Furthermore, we identified metallopeptidases 1, 12, and 13 as overexpressed in coiled versus untreated aneurysms.

CONCLUSIONS

We observed different physiopathologic responses after endovascular treatment with various devices. Flow diverters promote endothelialization but express molecules that could potentially explain the rare delayed ruptures. Coils promote wound healing and express genes potentially implicated in the recurrence of coiled aneurysms.

Popular Glucose Tracking Apps and Use of mHealth by Latinos With Diabetes: Review

BACKGROUND

Diabetes mellitus in the United States is an increasingly common chronic disease, costing hundreds of billions of dollars and contributing to hundreds of thousands of deaths each year. The prevalence of diabetes is over 50% higher in Latinos than in the general population, and this group also suffers from higher rates of complications and diabetes-related mortality than NHWs. mHealth is a promising new treatment modality for diabetes, though few smartphone apps have been designed specifically for Latinos.

OBJECTIVE

The objectives of our study were: (1) to identify the most common features of the most popular diabetes apps and consider how such features may be improved to meet the needs of Latinos; (2) to determine the use of diabetes apps among a sample of online Hispanics in the US.

METHODS

Our study consisted of two parts. First, 20 of the most popular diabetes apps were reviewed in order to ascertain the most prevalent features and functionalities. Second, an online survey was fielded through a popular health website for Latinos (HolaDoctor) inquiring about respondents' use of diabetes apps.

RESULTS

Approximately one-third of apps reviewed were available in Spanish. The most common features were blood glucose recording/annotation and activity logs. The majority of apps permitted exportation of data via e-mail but only a third enabled uploading to an online account. Twenty percent of apps reviewed could connect directly with a glucometer, and 30% had reminder functionalities prompting patients to take medications or check blood glucose levels. Over 1600 online surveys were completed during the second half of April 2014. More than 90% of respondents were from the United States, including Puerto Rico. The majority of respondents used a device running on an Android platform while only a quarter used an iPhone. Use of diabetes apps was approximately 3% among diabetic respondents and 3.6% among diabetic respondents who also had a smartphone. Among app users, blood glucose and medication diaries were the most frequently used functionalities while hemoglobin A1c and insulin diaries were the least used. A significant majority of app users did not share their progress on social media though many of these were willing to share it with their doctor.

CONCLUSIONS

Latino diabetics have unique needs and this should be reflected in diabetes apps designed for this population. Existing research as well as our survey results suggest that many Latinos do not possess the prerequisite diabetes knowledge or self-awareness to fully benefit from the most prevalent functionalities offered by the most popular diabetes apps. We recommend developers incorporate more basic features such as diabetes education, reminders to check blood glucose levels or take medications, Spanish language interfaces, and glucometer connectivities, which are relatively underrepresented in the most popular diabetes apps currently available in Spanish.

Modifications in integrin expression and extracellular matrix composition in children with biliary atresia

BACKGROUND

The aetiology of biliary atresia (BA) is still unresolved. The study's aim was to investigate the distribution of extracellular matrix proteins and cellular adhesion molecules in children with BA compared to other cholestatic liver disease (CLD) and normal liver architecture (NLA).

PATIENTS

Liver biopsies were obtained from children with BA (n=13), CLD (n=6) and NLA (n=8).

METHOD

We systematically analysed ultra thin frozen sections from the liver hilum stained with 25 monoclonal antibodies for cellular characterisation, extracellular matrix proteins and adhesion molecules.

RESULTS

2 changes were specifically found in BA: laminin beta1 was reduced in children with BA vs. NLA and CLD. Conversely, integrin alpha 3 was increased in BA vs. NLA and CLD (p<0.05). Furthermore, we detected changes in a similar pattern for both BA and CLD vs. NLA: in BA and CLD perlecan was increased. On the contrary, integrin beta1 and entactin were decreased vs. NLA (p<0.05).

DISCUSSION

Extracellular matrix proteins and adhesion molecules mediate cellular polarity and integrity, development of tubular structures, and proliferation. Therefore, our findings can be important for the understanding of the genesis of BA.

CONCLUSION

The composition of extracellular matrix proteins and adhesion molecules in children with BA differs from NLA and other CLD in distribution of laminin beta1 and integrin alpha 3, which may have implications for genetic, immunologic and environmental associations in BA.

Impact of the European clinical trials directive on prospective academic clinical trials associated with BMT

The European Clinical Trials Directive (EU 2001; 2001/20/EC) was introduced to improve the efficiency of commercial and academic clinical trials. Concerns have been raised by interested organizations and institutions regarding the potential for negative impact of the Directive on non-commercial European clinical research. Interested researchers within the European Group for Blood and Marrow Transplantation (EBMT) were surveyed to determine whether researcher experiences confirmed this view. Following a pilot study, an internet-based questionnaire was distributed to individuals in key research positions in the European haemopoietic SCT community. Seventy-one usable questionnaires were returned from participants in different EU member states. The results indicate that the perceived impact of the European Clinical Trials Directive has been negative, at least in the research areas of interest to the EBMT.

Glycosylation of proteinase 3 (PR3) is not required for its reactivity with antineutrophil cytoplasmic antibodies (ANCA) in Wegener's granulomatosis

OBJECTIVE

The glycosylation status of autoantigens appears to be crucial for the pathogenesis of some autoimmune diseases, since carbohydrates play a crucial role in the distinction of self from non-self. Proteinase 3 (PR3), the main target antigen for anti-neutrophil cytoplasmic antibodies (ANCA) in patients with Wegener's granulomatosis (WG), contains two Asn-linked glycosylation sites. The present study explores the influence of the glycosylation status of PR3 on the PR3 recognition by ANCA in a well characterized population of patients with WG.

METHODS

Forty-four patients with WG (459 serum samples) who participated in a multicenter randomized trial, were tested by capture ELISA for ANCA against PR3 and deglycosylated recombinant variants of PR3.

RESULTS

The patients were followed for a median of 27 months, and the median number of serum samples per patient was 10. At baseline, the correlation between the levels of ANCA against PR3 and against all the deglycosylated recombinant variants of PR3 were greater than 0.94 (?<0.001 for all the comparisons). Longitudinal analyses comparing the levels of ANCA against PR3 versus all the deglycosylated recombinant variants of PR3, using linear mixed models, showed no significant statistical differences (rho >or=0.90 in all cases).

CONCLUSION

The glycosylation status of PR3 has no impact on its recognition by ANCA in WG.

Benefit sharing: it's time for a definition

Benefit sharing has been a recurrent theme in international debates for the past two decades. However, despite its prominence in law, medical ethics and political philosophy, the concept has never been satisfactorily defined. In this conceptual paper, a definition that combines current legal guidelines with input from ethics debates is developed. Philosophers like boxes; protective casings into which they can put concisely-defined concepts. Autonomy is the human capacity for self-determination; beneficence denotes the virtue of good deeds, coercion is the intentional threat of harm and so on. What about benefit sharing? Does the concept have a box and are the contents clearly defined? The answer to this question has to be no. The concept of benefit sharing is almost unique in that various disciplines use it regularly without precise definitions. In this article, a definition for benefit sharing is provided, to eliminate unnecessary ambiguity.

[Indications for tonsillectomy in 2005]

Tonsillectomy is one of the most frequent ENT operations but yet a very disputed one. The majority of children and adults are treated for recurrent angina, which is validated by several clinical trials. For an adult a peritonsillar abscess is best treated by immediate tonsillectomy. Incision and drainage is a validated method as well, as long as there is no indication to a delayed tonsillectomy. The tonsillectomy alone is not a validated treatment for adult upper airway obstruction. On the other hand it is a recommended procedure for children upper airway obstruction. Partial tonsillectomy (tonsillotomy) is also a validated procedure for this indication. Finally the peritonsillar abscess in a child should first be treated by one or two days of intravenous antibiotics.

Comparison of a positive deviance inquiry with a case-control study to identify factors associated with nutritional status among Afghan refugee children in Pakistan

We compared the positive deviance (PD) approach in Save the Children's field guide with a case-control study (CCS) to identify behaviors associated with good nutritional status in Afghan refugee children 6 to 24 months of age in the Northwest Frontier Province (NWFP), Pakistan. The positive deviance inquiry (PDI), utilizing observations and interviews with mothers, fathers, and secondary caregivers in eight households, identified 12 feeding, caring, and health-seeking behaviors that were not widely practiced. The CCS, using the same selection criteria and content as the PDI with 50 mother-child pairs not in the PDI, yielded six significant associations with good nutritional status. Both the PDI and CCS detected feeding behaviors. The PDI alone identified complex phenomena (active feeding and maternal affect). The CCS alone confirmed the beneficial use of health services. The PD approach was an affordable, participatory, and valid method to identify feeding behaviors and other factors associated with good nutrition in this context.

Validation of a semi-quantitative food-frequency questionnaire for use among adults in Guatemala

OBJECTIVE

The purpose of the study was to assess the validity of a 52-item semi-quantitative food-frequency questionnaire (FFQ) by comparing it with multiple 24-hour dietary recalls.

DESIGN

Three non-consecutive 24-hour dietary recalls and one FFQ were administered over a one-month period.

SETTING

Four communities of El Progreso, Guatemala.

SUBJECTS

Seventy-three individuals aged 22-55 years.

RESULTS

: Intakes of energy and other nutrients as measured by the FFQ were higher than intakes measured by 24-hour recalls. Energy was overestimated by 361 kcal, and nutrient overestimates were particularly great for vitamin C and iron. Pearson correlation coefficients for crude energy and nutrients intakes ranged from 0.64 for energy to 0.12 for vitamin C. Exact agreement for both methods (measured by the concordance correlation coefficient) ranged from 0.59 (fat) to 0.06 (vitamin C). Pearson correlation coefficients for energy-adjusted nutrients ranged from 0.59 (carbohydrates) to 0.11 (thiamin). Pearson correlation coefficients for the proportion of total energy derived from specific foods ranged from 0.59 (tortillas) to 0.01 (sugared beverages). Cross-classification of quartiles of crude nutrient intakes for both methods indicated that <11% were grossly misclassified; after adjusting for energy intake, <13% were grossly misclassified.

CONCLUSIONS

This FFQ provides good measures of energy and macronutrient intakes and a reasonably reliable measure of micronutrient intake, indicating its suitability for comparing exposures within a study population in reference to heath-related endpoints. Our results highlight the need to adapt any FFQ to specific cultural needs - in this case, the Guatemalan 'core foods' (tortilla, bread and beans), for which inter-individual variability in intake is high.

Rural-to-urban migration and cardiovascular disease risk factors in young Guatemalan adults

BACKGROUND

Migration to cities may increase cardiovascular disease risk factors in developing countries. We examined rural and urban individuals who were born in the same villages and shared similar childhood experiences.

METHODS

Blood lipids and glucose, blood pressure, anthropometry, body composition, physical activity, and food, tobacco and alcohol consumption were examined in 161 men and 193 women, 19-29 years old, living in their village of birth (76 commuted to work in Guatemala City), and in 76 men and 43 women living in the city.

RESULTS

Rural and urban women had similar prevalence of overweight (28%), elevated body fat (29.8 +/- 6.1%) and low physical activity (83%). Compared to rural men, more urban men were sedentary (79 versus 27%), and they had higher body fat (15.3 +/- 5.3% versus 13.3 +/- 5.7%), serum cholesterol (4.27 +/- 0.75 versus 3.90 +/- 0.70 mmol/l [165 +/- 29 versus 151 +/- 27 mg/dl]), low density lipoprotein [LDL]-cholesterol (2.66 +/- 0.72 versus 2.30 +/- 0.62 mmol/l [103 +/- 28 versus 89 +/- 24 mg/dl]) and total cholesterol/high density lipoprotein [HDL]-cholesterol ratio (4.6 +/- 1.0 versus 4.1 +/- 0.9). Commuters showed intermediate values. Women had higher serum cholesterol (4.43 +/- 0.80 mmol/l [171 +/- 31 mg/dl]) than men in rural and urban areas. Urban residents ate/drank more saturated fats, red meat and sweetened beverages, and less legumes.

CONCLUSIONS

High proportions of young Guatemalan women were overweight and sedentary. Migration to a city increased sedentarism and undesirable eating habits among men and women; men became fatter and their lipid profile worsened. Public health actions must address the prevention of emerging chronic diseases in countries still burdened by undernutrition and infections.

Time- and depth-dependent changes in crosslinking and oxidation of shelf-aged polyethylene acetabular liners

Since crosslinking and oxidation of ultrahigh-molecular-weight polyethylene (UHMWPE) have important roles in determining the wear resistance of UHMWPE total joint components, the time and depth dependence of crosslinking and oxidation of new shelf-aged (2-11 years), ready-to-implant acetabular liners were studied by using solvent extraction and Fourier transform infrared spectroscopy. The ultrastructure of these materials also was examined by using low-voltage scanning electron microscopy in an oil-free vacuum. Oxidation levels increased with time and with depth (p < 0.0001) from the surface of the older liners to a maximum value at about 1-2 mm below the surface, then decreased. They were minimal at the midsection of the liners. The crosslinking of these liners decreased with time and depth (p < 0.0001) and was inversely proportional to the level of oxidation. High and depth-dependent oxidation levels were observed in all older liners made from GUR 415 and 412 resins but were distinctly absent from a comparably aged (i.e., 9 years) liner made from 1900 CM-resin. Some liners showed varying degrees of inhomogeneous and discontinuous morphologic ultrastructure in addition to varying amounts of porosity while others had a more homogeneous ultrastructure. Oxidation and crosslinking of polyethylene are time- and depth-dependent processes that are mutually competitive. We suggest that resin choice and perhaps consolidation-related variables lead to differences in polyethylene's ultrastructure. These ultrastructural differences in polyethylene's inhomogeneities, that is, the type (interconnected or closed-cell) or extent may affect the oxidation resistance of polyethylene. While oxygen diffusion to free radicals in polyethylene already is known to explain some of these time- and depth-dependent effects, perhaps such ultrastructural variations also may facilitate or retard oxygen diffusion in this material. Resin-based ultrastructural variability partially may explain the variability in the clinical performance of polyethylene total joint implant components. Thus resin choice or processing modifications related to polyethylene's ultrastructure may increase its oxidation resistance and ultimately improve the clinical wear performance of polyethylene total joint orthopedic implants.

Molecular identification and sequence analysis of Hillarin, a novel protein localized at the axon hillock

The monoclonal antibody Lan3-15 identifies a novel protein, Hillarin, that is localized to the axon hillock of leech neurons. Using this antibody we have identified a full length cDNA coding for leech Hillarin and determined its sequence. The gene encodes a 1274 residue protein with a predicted molecular mass of 144013 Da. Data base searches revealed that leech Hillarin has potential orthologues in fly and nematode and that these proteins share two novel protein domains. The W180 domain is characterized by five conserved tryptophans whereas the H domains share 21 invariant residues. In contrast to the arrangement in fly and nematode the cassette containing the W180 and H domains is repeated twice in leech Hillarin. This suggests that the leech Hillarin sequence originated from a duplication event of an ancestral protein with single cassette structure.

Mechanical quality of tissue engineered cartilage: results after 6 and 12 weeks in vivo

Traumatic events are a primary cause for local lesions of articular cartilage. If treated early, restoration of the initial joint geometry and integrity may be achieved. In large defects, sufficient material is not available to bridge the affected area. Heterologeous transplantation is not well accepted due to the risk of infection and immune response. Alternatives are cartilage-like structures, which may be cultured in vitro and transplanted into the defect site. Critical to the success of these new tissues are their mechanical properties. Goals of this study were to generate a hyaline-like cartilage structure, to evaluate its performance in vivo and to verify that its cellular and material properties meet those of native cartilage. Hyaline-like cartilage specimens were generated in vitro and implanted in the backs of nude mice. Specimens were explanted after 6 and 12 weeks, mechanically tested using an indentation test and histologically examined. In mechanical testing, stiffness and failure load significantly increased between weeks 6 and 12. At 12 weeks, mechanical properties of the hyaline-like cartilage were comparable to those of native nasal septal cartilage. Compared to native articular cartilage, the engineered tissue achieved up to 30-50% in strength and mechanical stiffness. In histological examination, specimens showed neocartilage formation. The mechanical testing procedure proved to be sufficiently sensitive to identify differences in properties between cartilage specimens of different origin and at different stages of healing. As an adjunct to histological analysis, mechanical testing may be a valuable tool for judging the utility of engineered cartilage prior to a broad clinical usage.

Multiple obesity QTLs identified in an intercross between the NZO (New Zealand obese) and the SM (small) mouse strains

The inheritance of adiposity levels has been investigated in an intercross of the obese, diabetes-prone NZO and the small, lean SM mouse strains. Adiposity index (AI) was defined as the sum of four fat pad weights divided by body weight. DNA pools from fat and lean mice were analyzed with microsatellite variants to screen the genome for quantitative trait loci (QTLs) affecting AI. Ten significant QTLs affecting AI were identified on Chromosome (Chr) 1 (three loci), Chr 2, Chr 5 (two loci), Chr 6 (two loci), Chr 7, and Chr 17. Most of the QTLs appear to be novel. Several QTLs differentially affect specific fat depots. Thus, Chr 2 and Chr 7 QTLs affect gonadal more than inguinal fat, while the converse is true for the Chr 17 QTL. Gender influences the expression of several of the QTLs. For example, effects of the proximal Chr 1 QTL (Obq7) on AI appears to be primarily in males. The proximal AI QTL on Chr 6 (Obq13) maps near the neuropeptide Y (Npy) locus. Sequence analysis of the Npy gene revealed a 1-nucleotide deletion within a highly conserved portion of the 3' untranslated region in strain NZO. However, the deletion is polymorphic among mouse strains. Furthermore, lack of association between this same variant and AI in previously analyzed crosses raises doubt that it is the basis of Obq13. The present cross is the fourth in a series of intercrosses among 10 inbred strains arranged such that each strain is crossed with each adjacent strain within a circle. This design affords multiple opportunities to analyze each segregating QTL.

Ultra-low wear rates for rigid-on-rigid bearings in total hip replacements

With the increased clinical interest in metal-on-metal and ceramic-on-ceramic total-hip replacements (THRs), the objective of this hip simulator study was to identify the relative wear ranking of three bearing systems, namely CoCr-polyethylene (M-PE), CoCr-CoCr (M-M) and ceramic-on-ceramic (C-C). Volumetric wear rates were used as the method of comparison. The seven THR groupings included one M-PE study, two M-M studies and four C-C studies. Special emphasis was given to defining the 'run-in' phase of accelerated wear that rigid-on-rigid bearings generally exhibit. The hypothesis was that characterization of the run-in and steady state wear phases would clarify not only the tribological performance in vitro but also help correlate these in vitro wear rates with the 'average' wear rates measured on retrieved implants. The implant systems were studied on multichannel hip simulators using the Paul gait cycle and bovine serum as the lubricant. With 28 mm CoCr heads, the PE (2.5 Mrad/N2) wear rates averaged 13 mm3/10(6) cycles duration. This was considered a low value compared with the clinical model of 74 mm3/year (for 28 mm heads). Our later studies established that this low laboratory value was a consequence of the serum parameters then in use. The mating CoCr heads (with PE cups) wore at the steady state rate of 0.028 mm3/10(6) cycles. The concurrently run Metasul M-M THRs wore at the steady state rate of 0.119 mm3/10(6) cycles with high-protein serum. In the second Metasul M-M study with low-protein serum, the THR run-in rate was 2.681 mm3/10(6) cycles and steady state was 0.977 mm3/10(6) cycles. At 10 years, these data would predict a 70-fold reduction in M-M wear debris compared with the clinical PE wear model. All M-M implants exhibited biphasic wear trends, with the transition point at 0.5 x 10(6) cycles between run-in and steady state phases, the latter averaging a 3-fold decrease in wear rate. White surface coatings on implants (coming from the serum solution) were a confounding factor but did not obscure the two orders of magnitude wear performance improvement for CoCr over PE cups. The liners in the alumina head-alumina cup combination wore at the steady state rate of 0.004 mm3/10(6) cycles over 14 x 10(6) cycles duration (high-protein serum). The zirconia head-alumina cup THR combination wore at 0.174 and 0.014 mm3/10(6) cycles for run-in and steady state rates respectively (low-protein serum). The zirconia head and cup THR combination wore slightly higher initially with 0.342 and 0.013 mm3/10(6) cycles for run-in and steady state rates respectively. Other wear studies have generally predicted catastrophic wear for such zirconia-ceramic combinations. It was noted that the zirconia wear trends were frequently masked by the effects of tenacious white surface coatings. It was possible that these coatings protected the zirconia surfaces somewhat in this simulator study. The experimental ceramic Crystaloy THR had the highest ceramic run-in wear at 0.681 mm3/10(6) cycles and typical 0.016 mm3/10(6) cycles for steady state. Since these implants represented the first Crystaloy THR sets made, it was likely that the surface conditions of this high-strength ceramic could be improved in the future. Overall, the ceramic THRs demonstrated three orders of magnitude wear performance improvement over PE cups. With zirconia implants, while the cup wear was sometimes measurable, head wear was seldom discernible. Therefore, we have to be cautious in interpreting such zirconia wear data. Identifying the run-in and steady state wear rates was a valuable step in processing the ceramic wear data and assessing its reliability. Thus, the M-M and C-C THRs have demonstrated two to three orders of reduction in volumetric wear in the laboratory compared with the PE wear standard, which helps to explain the excellent wear performance and minimal osteolysis seen with such implants at retrieval operations.

Co-occurrence of nutrition problems in Honduran children

We used data from the 1996 Honduras National Micronutrient Survey to investigate the co-occurrence of vitamin A deficiency (VAD), anemia and stunting in a representative sample of Honduran children 1-5 y old. Observed frequencies of co-occurrence were compared with frequencies expected by chance in children 12-35.9 mo old (n = 633) and 36-59.9 mo old (n = 610) for the three possible two-way combinations of the problems and the three-way combination. Observed frequencies were greater than expected frequencies for all eight comparisons, and all comparisons except for that of stunting and anemia in younger children were significant. The observed frequency of the three-way co-occurrence was 8.4% compared with an expected co-occurrence of 8.1% in younger children (P: < 0.05) and 4.8% compared with 4.2%, respectively, in older children (P: < 0.001). Although there was statistical evidence for co-occurrence, differences between expected and observed prevalences were small for most comparisons. Our findings suggest that having one or two problems does not appreciably increase the probability of having another. The efficiency of nutrition interventions aimed at these conditions would not be improved by targeting children with any one of the conditions; rather, the three conditions should be treated as virtually independent when designing programs. Replication of this study in other settings is warranted.

Green fluorescent protein functions as a reporter for protein localization in Escherichia coli

The use of green fluorescent protein (GFP) as a reporter for protein localization in Escherichia coli was explored by creating gene fusions between malE (encoding maltose-binding protein [MBP]) and a variant of gfp optimized for fluorescence in bacteria (GFPuv). These constructs encode hybrid proteins composed of GFP fused to the carboxy-terminal end of MBP. Fluorescence was not detected when the hybrid protein was synthesized with the MBP signal sequence. In contrast, when the MBP signal sequence was deleted, fluorescence was observed. Cell fractionation studies showed that the fluorescent MBP-GFP hybrid protein was localized in the cytoplasm, whereas the nonfluorescent version was localized to the periplasmic space. Smaller MBP-GFP hybrid proteins, however, exhibited abnormal fractionation. Expression of the gene fusions in different sec mutants, as well as signal sequence processing assays, confirmed that the periplasmically localized hybrid proteins were exported by the sec-dependent pathway. The distinction between fluorescent and nonfluorescent colonies was exploited as a scorable phenotype to isolate malE signal sequence mutations. While expression of hybrid proteins comprised of full-length MBP did not result in overproduction lethality characteristic of some exported beta-galactosidase hybrid proteins, synthesis of shorter, exported hybrid proteins was toxic to the cells. Purification of MBP-GFP hybrid protein from the different cellular compartments indicated that GFP is improperly folded when localized outside of the cytoplasm. These results suggest that GFP could serve as a useful reporter for genetic analysis of bacterial protein export and of protein folding.

Health care and hospitalizations of young children born to cocaine-using women

OBJECTIVES

To examine the health care and hospitalizations of young children (birth to age 2 years) born to cocaine-using women and to assess the extent to which premature births account for differences between these children and comparison children.

DESIGN

A retrospective cohort design using a repeat-matching method: comparison children were matched to subjects with exposure to cocaine on 6 sociodemographic variables, first, without attention to gestational age and then using the gestational age as additional matching variable.

SETTING

City hospitals and primary care clinics.

SUBJECTS

Children of women giving birth at a single hospital.

MAIN OUTCOME MEASURES

Hospital admission and indexes of health care use for children from birth to age 2 years.

RESULTS

Of the 139 subjects with exposure to cocaine, 23% were born prematurely compared with only 6% in the first comparison ( P < .001). At birth, children with exposure to cocaine remained in the hospital longer (P < .01), but this difference was explained by the increased prevalence of prematurity. By age 2 years, these children had significantly fewer visits for health care maintenance (P < .001), were less likely to have completed immunizations (P < .05), and spend more days in the hospital than comparison children. These differences were not related to prematurity, but were explained by differences in sociodemographic characteristics.

CONCLUSION

Although prematurity is the major reason for lengthier hospital stays at birth of children with exposure to cocaine, adverse social factors contribute most to inadequate preventive health care and increased stays in the hospital in subsequent years.

Maltreatment of children born to women who used cocaine during pregnancy: a population-based study

BACKGROUND

Previous studies of maltreatment of children born to women who used cocaine during pregnancy have relied on either selected samples of infants identified at birth or biased, high-risk samples referred to protective services.

OBJECTIVE

To determine the relative risk of either maltreatment or placement outside the home during the first 2 years of life in children born to women who used cocaine during pregnancy compared with a sociodemographically similar comparison group.

PATIENTS

We reviewed the medical records of consecutive deliveries at Yale-New Haven Hospital from August 1, 1989 through September 30, 1990. Of the 1140 women who were eligible for the study, 173 had a positive history and/or a positive urine test for cocaine; 139 of the infants were included in the study. A comparison group of infants was chosen from 526 women whose obstetric records indicated that they had not used cocaine during pregnancy based on at least two separate notations in the record. For each of the 139 cocaine-exposed infants, an infant was chosen from the comparison group based on seven matching characteristics: date of birth, race, method of payment for the hospitalization, gestational age, mother's parity, mother's age at delivery, and timing of the first prenatal visit.

MAIN OUTCOME MEASURES

Children's medical records at the only two hospitals in the region, the two neighborhood health centers, and the only health maintenance organization were reviewed from birth to 2 years of age. Each injury was classified by two independent reviewers who used predefined criteria to distinguish maltreatment (physical abuse, neglect, or abandonment) from unintentional injuries. Placements outside the home were categorized according to whether the placement was in foster care or with a relative.

MAIN RESULTS

The children were mainly African-Americans (80%), and most were enrolled in Medicaid (96.5%). By 2 years of age, 9.3% of the infants in the cocaine-exposed group versus 1.4% in the comparison group had been maltreated [matched relative risk = 6.5; 95% confidence interval (CI) = 1.47, 28.80], and 25.9% vs 8.6% had spent some time in placement (matched relative risk = 5.0; 95% CI = 2.08, 12.01). After controlling for differences between the groups in baseline clinical and social variables, the adjusted odds ratios for both maltreatment (3.98; 95% CI = .81, 22.80) and placement (1.66; 95% CI = .74, 17. 83) decreased and were no longer statistically significant.

CONCLUSION

In this population-based study, children born to women who used cocaine during pregnancy were at a substantially increased risk of maltreatment or placement outside the home compared with a sociodemographically similar comparison group. Differences in baseline variables between the two groups, however, partially accounted for this increased risk. Therefore, a mother's use of cocaine is more likely a marker of increased risk rather than a single explanatory variable.

Insulin improves survival in a canine model of acute beta-blocker toxicity

STUDY OBJECTIVE

To compare the efficacy of a novel antidote, insulin, with standard treatments, glucagon and epinephrine, in a canine model of acute beta-blocker toxicity.

METHODS

Anesthetized dogs were fitted with instruments by means of thoracotomy and vascular cutdown for multiple cardiodynamic, hemodynamic, metabolic, and electrical measures. After basal measurements were taken, animals received intravenous propranolol (.25 mg/kg/minute) continuously for the remainder of the experiment. Toxicity was defined as a 25% decrease in the product of heart rate times mean blood pressure. Thirty minutes after the development of toxicity, toxic measures were taken (treatment 0 minutes), and then the animals (n = 6 each group) received either sham (saline solution), insulin (4 IU/minute with glucose clamped), glucagon (50 micrograms/kg bolus, then 150 micrograms/kg/hour infusion), or epinephrine (1 microgram/kg/minute). Animals were monitored until death or for 240 minutes.

RESULTS

Propranolol decreased contractility, left ventricular pressure, and systemic blood pressure, and resulted in death of all sham-treated animals by 150 minutes. Six of six insulin-treated, four of six glucagon-treated, and one of six epinephrine-treated animals survived. Survival was greater for insulin-treated animals, compared with either glucagon-treated (P < .05) or epinephrine-treated animals (P < .02) by the log-rank test. Insulin-treated animals were characterized by improved cardiodynamics and hemodynamics, increased myocardial glucose uptake, and decreased serum potassium.

CONCLUSION

Insulin is a superior antidote compared with glucagon or epinephrine in an anesthetized canine model of acute beta-blocker toxicity.

Overcoming limitations in elbow movement in the presence of antagonist hyperactivity

BACKGROUND AND PURPOSE

A traditional perspective on rehabilitation of patients with abnormal muscular hyperactivity presumes that relaxation should be facilitated prior to recruitment of antagonists, if effective movement about a joint is to occur. The purpose of the study was to determine the effect of training weak triceps brachii muscles, with hyperactivity present in the opposing biceps brachii muscles, on elbow function in individuals at least 1 year poststroke.

SUBJECTS

Sixteen patients with chronic stroke were randomly assigned to receive electromyographic biofeedback to retrain the triceps muscle (n = 8) or to receive conventional movement training (n = 8).

METHODS

Both groups participated in 5 baseline and 10 training sessions involving tasks requiring elbow extension. Preintervention and postintervention measurements included elbow extension range of motion, triceps and biceps muscle electromyographic activity during performance of elbow extension, resisted elbow extension, and a reaching task.

RESULTS

Two-sample t-test results of between-group comparisons for each variable were not significant. One-sample t-test results of within-group comparisons showed significant increases in triceps muscle mean electromyographic activity during two of the three tasks for the feedback group, but not for the nonfeedback group. Passive and active range of motion in both groups increased significantly, although biceps muscle co-contraction persisted.

CONCLUSION AND DISCUSSION

These results suggest that functional improvements at the elbow may have been due to biomechanical (peripheral) rather than neuromuscular (central) changes about the joint. Furthermore, these preliminary data indicate that patients with stroke may be trained to increase movement without first being trained to specifically inhibit hyperactivity in muscles.

Blink rate: a possible measure of fatigue

The literature on blink rate as a measure of fatigue is reviewed. The evidence of increases in blink rate as a function of time on task is compelling. However, variables other than time on task also affect blink rate. These variables range from perceptual demandingness of the task to cognitive variables. Other aspects of blinking, such as flurries of blinks, timing with respect to information-processing demands, and blink closure duration, are reviewed as additional variables sensitive to task demands and fatigue effects.

Laparoscopic retroperitoneal left adrenalectomy in a patient with Cushing's syndrome

A technique for the extraperitoneal removal of the adrenal gland using laparoscopic instrumentation and insufflation is described. A case of Cushing's syndrome in a 42 year old female is presented with successful removal of her adrenal tumour using the laparoscopic method. This is the first report of laparoscopic adrenalectomy employing the extraperitoneal approach.

Postoperative fatigue after laparoscopic surgery

Postoperative fatigue (POF) appears to be less following laparoscopic surgery but this has not been proven previously. This study compared a group of patients who had undergone open cholecystectomy with a group undergoing laparoscopic cholecystectomy. Postoperative fatigue was found to be decreased in duration in the patients having laparoscopic surgery, returning to pre-operative fatigue levels by 14 days, compared to 28 days for open surgery. Postoperative pain in the first 24 h and the early metabolic response to surgery were similar for both groups. The authors conclude that laparoscopic surgery is associated with decreased POF and that this is unlikely to be accounted for by a decrease in the early metabolic response to surgery.

Metabolic basis for the management of patients undergoing major surgery

After reviewing our current knowledge of the metabolic response to major abdominal surgery, we present two new studies in which we have followed the changes in body composition, physiologic function, and psychological function for up to 1 year after major surgery. In the first study, 46 patients had changes in body composition, physiologic function, and psychological function measured perioperatively and again at intervals up to 1 year. There was an average loss of weight of 3000 grams (maximum at 2 weeks), and the tissue composition of this weight loss was composed of 1400 grams fat, 600 grams protein, and 1000 grams water. Normal body composition had returned to normal in most patients by 6 months. In the second study of 84 patients, deficits of skeletal muscle function and fatigue were found to be greatest at postoperative day 7. Most patients were back to preoperative levels of muscle function and fatigue 30 days after surgery, and nearly all had normal values 90 days after surgery. Based on these studies we outline our management program for the metabolic care of patients undergoing major abdominal surgery.

Predicting postoperative fatigue: importance of preoperative factors

Postoperative fatigue as defined by a 10-point scale (1 = fit, 10 = fatigued) was determined prospectively in 84 patients undergoing major surgery. Results from this scale correlated well with standard psychological assessment of fatigue (Profile of Mood States Questionnaire) (r = 0.767; p < 0.0001). Fatigue values were 3.46 +/- 0.19 arbitrary units (mean +/- SEM) preoperatively; and postoperatively they were 5.61 +/- 0.24 at day 7, 5.02 +/- 0.24 at day 14, 3.74 +/- 0.19 at day 28, and 2.77 +/- 0.18 at day 90. Fatigue during the postoperative period was integrated to give a total fatigue score (332 +/- 14 arbitrary units, range 90-664), and this score was correlated with preoperative and early postoperative factors. The best predictor of postoperative fatigue was preoperative fatigue (r = 0.545; p = 0.001), with lesser correlations with diagnosis (especially cancer); preoperative weight, particularly total body protein (r = 0.317; p = 0.01); and weight loss (r = 0.29; p = 0.03), grip strength (r = 0.352; p = 0.01), and age (r = 0.267; p = 0.01). Postoperative fatigue was not correlated with preoperative anxiety, depression, or hostility, involuntary muscle function, gender, preoperative stress, or changes in total body protein or fat over the two postoperative weeks. It is concluded that patients who present for surgery already fatigued are the ones who are most likely to suffer from prolonged postoperative fatigue, particularly so if they are elderly, suffer from cancer, or have few extra reserves of body protein.

Laparoscopy in the diagnosis and treatment of acute small bowel obstruction

The surgical correction of acute small bowel obstruction is conventionally performed through a vertical laparotomy incision. The increasing use of the laparoscope for elective general surgery has led to an increase in its use for the diagnosis and treatment of acute abdominal conditions. The authors report five cases of acute small bowel obstruction treated with the aid of the laparoscope. All five patients were able to leave the hospital in the early postoperative period and remain symptom free. Laparoscopy is a useful technique in the management of selected cases of small bowel obstruction.

Hypotension and endoscopic stigmata of recent haemorrhage in bleeding peptic ulcer: risk models for rebleeding and mortality

Clinical and endoscopic data were collected prospectively in 1050 patients with bleeding peptic ulcer admitted between September 1985 and July 1989 to the care of one surgical team. Seventy-nine patients underwent therapeutic endoscopy soon after admission and in 129 patients either immediate or early elective surgery was performed. Eight hundred and forty-two patients, in whom therapeutic endoscopy was not performed at any stage, underwent initial conservative management and data from this latter group are now presented. Shock on admission was defined as systolic blood pressure (BP) less than or equal to 100 mmHg on presentation. There were 10 deaths of 147 shocked patients (6.8%) compared with only 25 deaths of 695 patients (3.6%) not in shock (P less than 0.08). Bleeding recurred in 30 patients (20.4%) shocked on presentation but in only 96 (13.8%) with a BP greater than 100 mmHg (P less than 0.05). Twenty-one of 358 patients (5.9%) with endoscopic stigmata of recent haemorrhage (ESRH) died, but only 14 of 484 patients (2.9%) without such stigmata (P less than 0.05) died. In shocked patients rebleeding was evident in 21 of 73 (28.8%) cases with ESRH but in only 9 of 74 (12.2%) patients in whom ESRH were absent (P less than 0.02). In the absence of fresh blood at endoscopy rebleeding occurred in 22 of 124 (17.8%) shocked patients and only 74 of 629 (11.8%) of those not shocked on presentation (P less than 0.07). When ulcer size was documented rebleeding rates for ulcers less than or equal to 1 cm, less than or equal to 2 cm and greater than 2 cm in size were 54 of 485 (11.1%), 30 of 142 (21.2%) and 12 of 44 (27.3%) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The protective efficacy of polyvalent pneumococcal polysaccharide vaccine

BACKGROUND

Although the protective efficacy of pneumococcal polysaccharide vaccine has been demonstrated in randomized trials in young African gold miners, there has been controversy about its efficacy in older Americans at risk for serious pneumococcal infections. To assess the vaccine's protective efficacy against invasive pneumococcal infections, we conducted a hospital-based case-control study of the efficacy of pneumococcal vaccine in adults with a condition recognized to be an indication for receiving the vaccine.

METHODS

From 1984 to 1990, adults in whom Streptococcus pneumoniae was isolated from any normally sterile site were identified by prospective surveillance in the microbiology laboratories of 11 large hospitals; those with an indication for pneumococcal vaccine were enrolled as case patients. For each case patient, one control was matched according to age, underlying illness, and site of hospitalization. We contacted all providers of medical care to ascertain each subject's history of immunization with pneumococcal vaccine. Isolates of S. pneumoniae were serotyped by an investigator unaware of the subject's vaccination history.

RESULTS

Thirteen percent of the 1,054 case patients and 20 percent of the 1,054 matched controls had received pneumococcal vaccine (P less than 0.001). When vaccine was given in either its 14-valent or its 23-valent form, its aggregate protective efficacy (calculated as a percentage: 1 minus the odds ratio of having been vaccinated times 100) against infections caused by the serotypes represented in the vaccine was 56 percent (95 percent confidence interval, 42 percent to 67 percent; P less than 0.00001) for all 983 patients infected with a serotype represented in the vaccine, 61 percent for a subgroup of 808 immunocompetent patients (95 percent confidence interval, 47 percent to 72 percent; P less than 0.00001), and 21 percent for a subgroup of 175 immunocompromised patients (95 percent confidence interval, -55 percent to 60 percent; P = 0.48). The vaccine was not efficacious against infections caused by serotypes not represented in the vaccine (protective efficacy, -73 percent; 95 percent confidence interval, -263 percent to 18 percent; P = 0.15).

CONCLUSIONS

Polyvalent pneumococcal vaccine is efficacious in preventing invasive pneumococcal infections in immunocompetent patients with indications for its administration. This vaccine should be used more widely.