Factors associated with injury among Maine logging workers

INTRODUCTION

Despite dramatic improvements in safety, logging remains one of the most dangerous industries in the United States. The purpose of this study was to explore longitudinal injury trends among Maine logging workers.

METHODS

Loggers participated in seven quarterly surveys, over the course of 18 months. Categorical and free text data related to traumatic and acute injury, musculoskeletal disorders (MSD), and chronic pain were exported from REDCap into SAS 9.4, Excel, and NVivo, for quantitative and qualitative analysis, respectively. Time to injury was modeled using two different approaches: (1) time to the occurrence of first injury modeled by proportional hazard regression and (2) an intensity model for injury frequency. Two research team members also analyzed qualitative data using a content analysis approach.

RESULTS

During the study, 204 injuries were reported. Of the 154 participants, 93 (60.4%) reported musculoskeletal pain on at least one survey. The majority of injuries were traumatic, including fractures, sprains, and strains. Lack of health insurance was found to be related to increased risk of first injury [HR = 1.41, 95% CI = 0.97-2.04, p = 0.069]. Variables found to be related to injury intensity at the univariate level were: (1) a lack of health insurance [HR = 1.51, 95% CI = 1.04-2.20, p = 0.030], (2) age [HR for 10-year age increase;= 1.12, 95% CI = 0.99-1.27, p = 0.082], and (3) years employed in logging industry [HR for 10-year increase = 1.12, 95% CI = 0.99-1.26, p = 0.052]. Seeking medical attention for injury was not a priority for this cohort, and narratives revealed a trend for self-assessment. A variety of barriers, including finances, prevented loggers from seeking medical attention.

DISCUSSION

We found that loggers still experience serious, and sometimes disabling, injuries associated with their work. It was unsurprising that many injuries were due to slips, trips, and falls, along with contact with logging equipment and trees/logs. The narratives revealed various obstacles preventing loggers from achieving optimal health. Examples included geographic distance from healthcare, lack of time to access care, and entrenched values that prioritized independence and traditional masculinity. Financial considerations were also consistently cited as a primary barrier to adequate care.

CONCLUSION

There is a continued need to emphasize occupational health and safety in the logging industry. Implementation of relevant safety programs is key, but it is likely that the benefits of these will not be fully realized until a cultural shift takes place within this industry.

Uncertainty in low back pain care - insights from an ethnographic study

PURPOSE

To explore how uncertainty plays out in low back pain (LBP) care and investigate how clinicians manage accompanying emotions/tensions.

MATERIALS AND METHODS

We conducted ethnographic observations of clinical encounters in a private physiotherapy practice and a public multidisciplinary pain clinic. Our qualitative reflexive thematic analysis involved abductive thematic principles informed by Fox and Katz (medical uncertainty) and Ahmed (emotions).

RESULTS

We identified three themes. (1) Sources of uncertainty: both patients and clinicians expressed uncertainty during clinical encounters (e.g., causes of LBP, mismatch between imaging findings and presentation). Such uncertainty was often accompanied by emotions - anger, tiredness, frustration. (2) Neglecting complexity: clinicians often attempted to decrease uncertainty and associated emotions by providing narrow answers to questions about LBP. At times, clinicians' denial of uncertainty also appeared to deny patients the right to make informed decisions about treatments. (3) Attending to uncertainty?: clinicians attended to uncertainty through logical reasoning, reassurance, acknowledgement, personalising care, shifting power, adjusting language and disclosing risks.

CONCLUSIONS

Uncertainty pervades LBP care and is often accompanied by emotions, emphasising the need for a healthcare culture that recognises the emotional dimensions of patient-clinician interactions and prepares clinicians and patients to be more accepting of, and clearly communicate about, uncertainty.IMPLICATIONS FOR REHABILITATIONUncertainty pervades LBP care and is often accompanied by emotions.Neglecting complexity in LBP care may compromise person-centred care.Acknowledging uncertainty can enhance communication, balance patient-clinician relationships and address human aspects of care.

Biomarkers for occupational manganese exposure

Long-term inhalation exposure to manganese (Mn) metal or its inorganic compounds can result in manganism or subclinical neurofunctional deficits. Studies have described affected workers in Mn dioxide mining, Mn-containing ore crushing and milling facilities, manufacturing of dry-cell batteries, Mn steel and alloy production plants, and in welders. The objective of this study was to critically review existing evidence on the reliability of potential biomarkers of Mn exposure, specifically the relationship between inhalation exposure to Mn particulates in different occupational settings and Mn concentrations in blood and other biological fluids and tissues, with a particular focus on whole blood as a potentially useful medium for measuring internal tissue dose. We also examined available evidence on the relationship between Mn levels in blood and adverse clinical and subclinical neurotoxic outcomes. Three bibliographic databases were searched for relevant studies and identified references were screened by two independent reviewers. Of the 6338 unique references identified, 76 articles were retained for data abstraction. Findings indicate that the relationships between Mn in blood and both external Mn exposure indices and neurofunctional impairments are limited and inconsistent. Different sources of exposure to Mn compounds, heterogeneity in the methodological approaches, and inadequate reporting of essential information limited direct comparison of the reported findings. Among the Mn-exposure biomarkers considered in this review - including biomarkers in blood, plasma, serum, erythrocytes, urine, bone, toenails, fingernails, hair, saliva - biomarkers in whole blood may provide to be most useful in Mn biomonitoring and risk assessment.

Magnetic resonance imaging T1 indices of the brain as biomarkers of inhaled manganese exposure

Excessive exposure to manganese (Mn) is linked to its accumulation in the brain and adverse neurological effects. Paramagnetic properties of Mn allow the use of magnetic resonance imaging (MRI) techniques to identify it in biological tissues. A critical review was conducted to evaluate whether MRI techniques could be used as a diagnostic tool to detect brain Mn accumulation as a quantitative biomarker of inhaled exposure. A comprehensive search was conducted in MEDLINE, EMBASE, and PubMed to identify potentially relevant studies published prior to 9 May 2022. Two reviewers independently screened identified references using a two-stage process. Of the 6452 unique references identified, 36 articles were retained for data abstraction. Eligible studies used T1-weighted MRI techniques and reported direct or indirect T1 measures to characterize Mn accumulation in the brain. Findings demonstrate that, in subjects exposed to high levels of Mn, deposition in the brain is widespread, accumulating both within and outside the basal ganglia. Available evidence indicates that T1 MRI techniques can be used to distinguish Mn-exposed individuals from unexposed. Additionally, T1 MRI may be useful for semi-quantitative evaluation of inhaled Mn exposure, particularly when interpreted along with other exposure indices. T1 MRI measures appear to have a nonlinear relationship to Mn exposure duration, with R1 signal only increasing after critical thresholds. The strength of the association varied depending on the regions of interest imaged and the method of exposure measurement. Overall, available evidence suggests potential for future clinical and risk assessment applications of MRI as a diagnostic tool.

Health equity and health system strengthening - Time for a WHO re-think

The pursuit of health equity is foundational to the global health enterprise. But while moral concerns over health inequities can galvanise political commitment, how such concerns can or should translate into practice remains less clear. This paper reviews evolving ways that equity goals have featured in key World Health Organization (WHO)-related policy documents, before discussing the heuristic value and empirical traction that the concept of equity can bring to the health system strengthening (HSS) agenda. We argue that while health equity is often presented as the overarching goal of HSS, in practice this is typically circumscribed to the provision of healthcare services. Although healthcare equity is important, we suggest that this narrow focus risks losing sight of the structural political, social and economic drivers of health and health inequities, as well as the broader contexts of care and complex socio-political mechanisms through which health systems are strengthened. Drawing on new lines of empirical inquiry, we propose that broadening the equity lens for HSS -offers exciting opportunities to put health systems at the heart of a more ambitious equity agenda in global health.

Integrated transitional care for older patients discharged from hospital and ED

Background

Care integration through high level care continuation for older patients discharged from the hospital may secure positive health outcomes and reduce subsequent emergency visits. Integrated transitional care is, however, challenged by fragmented care delivery systems. We explored integrated transitional care from the delivery system perspective in three Nordic cities (Copenhagen, Stockholm and Tampere) to compare levels of integration of social and health service delivery systems and care paths for older patients discharged from hospital.

Methods

Information on organizational structure and care integration was obtained from administrative documents, legislation and statistics, webpages of the cities, and empirical studies. Based on the material we outlined the degree of integration at different levels and mapped the possible care paths for older patients discharged from the hospital for each city.

Results

All three cities are characterized by fragmented care systems for older patients based on financially and organizationally independent institutions. Sweden and Denmark, however, have introduced legislation to steer the integration of services between the local and regional level actors. However, older patients still have complex care paths after discharge from hospital care.

Conclusions

The fragmented care systems for older patients consisting of independent institutions across local and regional levels may impede integrated transitional care. Alternative care settings for older people with different needs could be an asset, but they can also form a hurdle for care continuation if the responsibilities and liaison between these sites are not clear.

Key messages

The fragmented organisation of care systems for older patients may impede integrated transitional care. The care facilities for older patients after discharge is targeted to accommodate the complex and varying needs, but pose challenges for continuity of care.

Neuropsychiatric disease relevance of circulating anti-NMDA receptor autoantibodies depends on blood-brain barrier integrity

In 2007, a multifaceted syndrome, associated with anti-NMDA receptor autoantibodies (NMDAR-AB) of immunoglobulin-G isotype, has been described, which variably consists of psychosis, epilepsy, cognitive decline and extrapyramidal symptoms. Prevalence and significance of NMDAR-AB in complex neuropsychiatric disease versus health, however, have remained unclear. We tested sera of 2817 subjects (1325 healthy, 1081 schizophrenic, 263 Parkinson and 148 affective-disorder subjects) for presence of NMDAR-AB, conducted a genome-wide genetic association study, comparing AB carriers versus non-carriers, and assessed their influenza AB status. For mechanistic insight and documentation of AB functionality, in vivo experiments involving mice with deficient blood-brain barrier (ApoE(-/-)) and in vitro endocytosis assays in primary cortical neurons were performed. In 10.5% of subjects, NMDAR-AB (NR1 subunit) of any immunoglobulin isotype were detected, with no difference in seroprevalence, titer or in vitro functionality between patients and healthy controls. Administration of extracted human serum to mice influenced basal and MK-801-induced activity in the open field only in ApoE(-/-) mice injected with NMDAR-AB-positive serum but not in respective controls. Seropositive schizophrenic patients with a history of neurotrauma or birth complications, indicating an at least temporarily compromised blood-brain barrier, had more neurological abnormalities than seronegative patients with comparable history. A common genetic variant (rs524991, P=6.15E-08) as well as past influenza A (P=0.024) or B (P=0.006) infection were identified as predisposing factors for NMDAR-AB seropositivity. The >10% overall seroprevalence of NMDAR-AB of both healthy individuals and patients is unexpectedly high. Clinical significance, however, apparently depends on association with past or present perturbations of blood-brain barrier function.

Determination and comparison of radiotherapy dose responses for hepatocellular carcinoma and metastatic colorectal liver tumours

OBJECTIVE

The purpose of this study was to seek radiation dose responses separately for primary hepatocellular carcinoma (HCC) and metastatic (MET) colorectal liver tumours to establish tumour control probabilities (TCPs) for radiotherapy (RT) of liver tumours.

METHODS

The records of 36 HCC and 26 MET colorectal liver tumour patients were reviewed. The median dose per fraction and total dose were 4 Gy (2-10 Gy) and 52 Gy (29-83 Gy) for the HCC group and 3.6 Gy (2.0-13.0 Gy) and 55 Gy (30-80 Gy) for the MET group, respectively. Median tumour diameter was 6.6 cm (3.0-18.0 cm) and 5.0 cm (1.0-13.0 cm) for the HCC and MET groups, respectively. A logistic TCP model was fitted to the response data for each group using the maximum likelihood method.

RESULTS

50% and 90% probabilities of 6-month local control were estimated to be achievable by 2 Gy per fraction equivalent doses (α/β=10 Gy) of 53 Gy and 84 Gy for the HCC group and 70 Gy and 95 Gy for the MET group, respectively. Actuarial 1-year local control for the HCC and MET groups was 65% (45-85%) and 32% (6-58%), respectively, whereas median time to failure was 543 days (374-711 days) and 183 days (72-294 days), respectively.

CONCLUSION

Dose-response relationships were found and modelled for the HCC and MET patient groups, with a higher dose required to control MET tumours. RT offers better local control for HCC than for MET colorectal liver tumours at our institution.

ADVANCES IN KNOWLEDGE

An improved understanding of radiation dose-response relationships for primary and MET colorectal liver tumours will help inform future dose prescriptions.

Salt, alone or in combination with sucrose, can improve the survival of Escherichia coli O157 (SERL 2) in model acidic sauces

The commercial production of microbiologically safe and stable sauces containing acetic acid is guided by the Comité des Industries des Mayonnaises et Sauces Condimentaires de la Communauté Economique Européenne's (CIMSCEE) code. The CIMSCEE safety value is calculated using a linear regression equation combining weighted contributions of pH and aqueous-phase concentrations of undissociated acetic acid, NaCl, and sugars. By implication, the CIMSCEE safety equation predicts that increasing concentrations of hurdles will always increase inactivation of the target pathogen. In this study, the time to achieve a 3-log10 reduction of an acid-resistant, acid-adapted, Shiga toxin-producing Escherichia coli (STEC) O157 isolate was determined experimentally for 81 formulations at various pHs and acetic acid, NaCl, and sucrose concentrations in a broth model. The combinations were intended to simulate the aqueous phase of acidic sauces and dressings. Experimental data were fitted to the log logistic model to estimate the time to 3-log10 reduction (t3D). Comparison of fitted t3D estimates with CIMSCEE values showed agreement in predicting safety (as defined by CIMSCEE) for the majority of formulations. However, CIMSCEE safety predictions were "fail dangerous" for 13 of 81 formulations. Among these formulations and others, the observed E. coli t3D initially increased and then decreased with increasing osmolalities (NaCl and sucrose). Relative protection increased with exposure time where the protective effect of NaCl predominated. While commercial acidic sauces are not considered high-risk vehicles for STEC, interactions among hurdles that decrease their combined effectiveness are deserving of further investigation because they may reveal mechanisms of broader relevance in the inactivation of pathogens in foods.

Effects of Three Months of Low Molecular Weight Heparin (dalteparin) Treatment After Bypass Surgery for Lower Limb Ischemia—A Randomised Placebo-controlled Double Blind Multicentre Trial

OBJECTIVES

To test the hypothesis that long-term postoperative dalteparin (Fragmin), Pharmacia Corp) treatment improves primary patency of peripheral arterial bypass grafts (PABG) in lower limb ischemia patients on acetylsalicylic acid (ASA) treatment.

DESIGN

Prospective randomised double blind multicenter study.

MATERIALS AND METHODS

Using a computer algorithm 284 patients with lower limb ischemia, most with pre-operative ischemic ulceration or partial gangrene, from 12 hospitals were randomised, after PABG, to 5000 IU dalteparin or placebo injections once daily for 3 months. All patients received 75 mg of ASA daily for 12 months. Graft patency was assessed at 1, 3 and 12 months.

RESULTS

At 1 year, 42 patients had died or were lost to follow-up. Compliance with the injection schedule was 80%. Primary patency rate, in the dalteparin versus the control group, respectively, was 83 versus 80% (n.s.) at 3 months and 59% for both groups at 12 months. Major complication rates and cardiovascular morbidity were not different between the two groups.

CONCLUSIONS

In patients on ASA treatment, long-term postoperative dalteparin treatment did not improve patency after peripheral artery bypass grafting. Therefore, low molecular weight heparin treatment cannot be recommended for routine use after bypass surgery for critical lower limb ischemia.

159 TWIN vs. SINGLE TRANSFER OF IVP HOLSTEIN HEIFER EMBRYOS TO BEEF RECIPIENTS

Use of sexed semen in conjunction with in vitro embryo production is a potentially efficient means of obtaining offspring of predetermined sex. Here we evaluate a production scheme involving single and bilateral twin transfer of Holstein female embryos to beef cattle recipients. Holstein oocytes were fertilized with the X-bearing fraction of gender-sorted Holstein semen. Cumulus cells were removed with aid of a vortex or microfluidic device (μFD). Half of the vortexed embryos were cultured in KSOMaaBSA (control), as were all μFD embryos. The remaining vortexed embryos were cultured in control medium with 6% avian white yolk (WY). Embryo production and transfer occurred across five replicates. Cows (n = 475) were synchronized using an Ovsynch protocol. They were administered GnRH on Day −9, PGF on Day −2, and GnRH on Day 0. Half of the cows received a CIDR (1.38 g progesterone) with the 1st GnRH injection. The CIDR was removed at the time of PGF treatment. Day 7 Grade 1 blastocysts were transferred fresh 7 days after the 2nd GnRH injection. Control and WY embryos were transferred as ipsilateral singles and bilateral twins; μFD embryos were transferred singly. Pregnancy was diagnosed with ultrasound between 41–46 days and confirmed between 60–90 days; fetal sexing confirmed that 95% of fetuses were female. Effects on embryo survival were analyzed by logistic regression. Chi-square analysis was applied to survival rates. Replication affected embryo survival (P < 0.05). There was no effect of cumulus removal, medium, or CIDR use. Fetal loss between ultrasounds was greater for twin vs. single transfers (30% vs. 15%, respectively; P < 0.01). Probability of embryo survival was estimated to increase ∼0.006 with each increasing day postpartum. Five cases of hydrallantois were detected during the 5th month of gestation for 1 control twin, 1 WY single, and 3 WY twin transfers, originating from 3 replicates. On a production per transfer basis, the proportion of fetuses obtained for single and twin transfers was 30% and 55%, respectively (P < 0.001). Although there was greater embryonic loss for twin compared to single transfers, a higher percentage of cows receiving twins established and maintained pregnancy. Large-scale transfer of IVP Holstein heifer embryos to beef recipients is a feasible production scheme. Table 1. Embryo survival and pregnancy rates

Role of Alicyclobacillus acidoterrestris in the development of a disinfectant taint in shelf-stable fruit juice

AIMS

This study was undertaken to identify the bacterium and metabolic products contributing to a disinfectant taint in shelf-stable fruit juice and to determine some of the growth conditions for the organism.

METHODS AND RESULTS

Microbiological examination of tainted and untainted fruit juice drinks detected low numbers of acid-dependent, thermotolerant, spore-forming bacteria in the tainted juices only. The presence of omega-cyclohexyl fatty acids was confirmed in two of the isolates by cell membrane fatty acid analysis. The isolates were subsequently identified as Alicyclobacillus acidoterrestris by partial 16S rDNA sequencing. Studies on the isolates showed growth at pH 2.5-6.0 and 19.5-58 degrees C. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify 2,6-dibromophenol (2,6-DBP) and 2,6-dichlorophenol (2,6-DCP) in the tainted juice. Challenge studies in a mixed fruit drink inoculated with the two isolates and the type strain of A. acidoterrestris, incubated at 44-46 degrees C for 4 d, showed the production of both metabolites, which were confirmed and quantified by GC/MS.

CONCLUSIONS

The results show that A. acidoterrestris can produce 2,6-DBP and 2,6-DCP in shelf-stable juices.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report detailing experimental methodology showing that A. acidoterrestris can produce 2,6-DCP in foods. Control of storage temperatures (to < 20 degrees C) immediately after processing may provide an effective control measure for the fruit juice industry to prevent spoilage by A. acidoterrestris.

Formation of guaiacol in chocolate milk by the psychrotrophic bacterium Rahnella aquatilis

AIMS

The aim of this study was to identify the causative agent of a smoky/phenolic taint in refrigerated full cream chocolate milk.

METHODS AND RESULTS

Microbiological examination of spoiled and unspoiled milk samples from the same processor showed high numbers of the psychrotrophic coliform Rahnella aquatilis in the spoiled samples only. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify the taint compound as guaiacol (2-methoxyphenol) in the spoiled milk. Challenge studies in UHT chocolate and white milks inoculated with the isolate and incubated at 4-5 degrees C and 8-9 degrees C for 6 d showed the production of guaiacol in chocolate milk only, which was confirmed and quantified by GC/MS.

CONCLUSIONS

The results indicate that if present in refrigerated chocolate milk, Rah. aquatilis can produce guaiacol within the expected shelf-life of the product, even without temperature abuse.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report that the coliform Rah. aquatilis can produce guaiacol in refrigerated chocolate milk products.

Frequency of nightly wetting and the efficiency of alarm treatment of nocturnal enuresis

OBJECTIVE

This study aimed to investigate the efficiency of alarm treatment in patients suffering from nocturnal enuresis (NE).

MATERIAL AND METHODS

The weekly frequency of nightly wetting was used as an indicator of the patient's predisposition for alarm treatment and thus of the efficiency of the alarm.

RESULTS

The pattern of relapse is shown in connection with a status I year after treatment ended for those who volunteered successful treatment.

CONCLUSIONS

Patients with the highest pretreatment frequencies of NE achieved better results from treatment with an alarm and ended up in a better situation than those with lower frequencies of NE receiving the same treatment.

Aerosol formation and reaction pathways of atmospheric oxidation of dimethylsulfide

This paper concerns with three series of experiments about dimethylsulfide gas phase oxidation, carried out at increasing NOx level (< 20 ppb, 1 ppm, 10 ppm) to show the relation between the amounts of nitrogen oxides and the molar yields of sulfur containing products. DMSO, DMSO2, HCHO, HCOOH and SO2 were found as main reaction products. From these experiments and from preceding studies, a sensitive decrease in the quantity of total sulfur products in aerosol phase is underlined. This result derives from the reaction of NOx with CH3S(O)O2 and CH3S(O)OO radicals, which leads to stable intermediates as methylsulphonylperoxynitrate, MSPN, with a characteristic PAN-like structure.

Cobalt(II), nickel(II), copper(II), and zinc(II) complexes with [3(5)]adamanzane, 1,5,9,13-tetraazabicyclo[7.7.3]nonadecane, and [(2.3)(2).2(1)] adamanzane, 1,5,9,12-tetraazabicyclo[7.5.2]hexadecane

Isolation of the free bicyclic tetraamine, [3(5)]adamanzane.H(2)O (1,5,9,13-tetraazabicyclo[7.7.3]nonadecane.H(2)O), is reported along with the synthesis and characterization of a copper(II) complex of the smaller macrocycle [(2.3)(2).2(1)]adamanzane (1,5,9,12-tetraazabicyclo[7.5.2]hexadecane) and of three cobalt(II), four nickel(II), one copper(II), and two zinc(II) complexes with [3(5)]adamanzane. For nine of these compounds (2-8, 10b, and 12) the single-crystal X-ray structures were determined. The coordination geometry around the metal ion is square pyramidal in [Cu([(2.3)(2).2(1)]adz)Br]ClO(4) (2) and trigonal bipyramidal in the isostructural structures [Cu([3(5)]adz)Br]Br (3), [Ni([3(5)]adz)Cl]Cl (5), [Ni([3(5)]adz)Br]Br (6), and [Co([3(5)]adz)Cl]Cl (8). In [Ni([3(5)]adz)(NO(3))]NO(3) (4) and [Ni([3(5)]adz)(ClO(4))]ClO(4) (7) the coordination geometry around nickel(II) is a distorted octahedron with the inorganic ligands at cis positions. The coordination polyhedron around the metal ion in [Co([3(5)]adz)][ZnCl(4)] (10b) and [Zn([3(5)]adz)][ZnCl(4)] (12) is a slightly distorted tetrahedron. Anation equilibrium constants were determined spectrophotometrically for complexes 2-6 at 25 and 40 degrees C and fall in the region 2-10 M(-1) for the halide complexes and 30-65 M(-1) for the nickel(II) nitrate complex (4). Rate constants for the dissociation of the macrocyclic ligand from the metal ions in 5 M HCl were determined for complexes 2, 3, 5, 8, 10, and 12. The reaction rates vary from half-lives at 40 degrees C of 14 min for the dissociation of the Zn([3(5)]adz)(2+) complex (12) to 14-15 months for the Ni([3(5)]adz)Cl(+) ion (5).

Blood gases and oximetry: calibration-free new dry-chemistry and optical technology for near-patient testing

The first calibration-free Near-Patient-Testing instrument (NPT7) for blood gases, pH and oximetry has been developed. With cartridges of 30 single-use cuvettes, the NPT7 needs no preparation prior to sample aspiration, no manual calibration, and no maintenance apart from paper and cartridge changes and regulatory quality control. Each cuvette measures pCO2, pO2, pH, total hemoglobin (ctHb), oxygen saturation (sO2), fractions of carboxyhemoglobin (FCOHb) and methemoglobin (FMetHb) on 95 microl whole blood with a 110-s measuring cycle. The measurement principles are as follows: pCO2-three-wavelength infrared spectroscopy of dissolved CO2; pO2-measurement of O2-induced changes in the decay time of phosphorescence; pH-the absorbance spectra change of an azo-dye color indicator; and oximetry is performed with a 128-wavelength spectrophotometer. We determined the within and between instrument variations with tonometered whole blood on seven prototype instruments, using between one and five control levels per analyte. The 95% analytical performance limits: +/-(/Bias/ +2 xS(T)) in the NPT7 instrument matched the analytical performance criteria for the measured quantities as defined by AACC guidelines. The application of these optical measuring methods for blood gases, pH and oximetry in single-use devices introduces a new concept into point-of-care testing (POCT), where preanalytical activities otherwise associated with instrument preparation are eliminated.

Role of Yersinia intermedia and Pseudomonas putida in the development of a fruity off-flavour in pasteurized milk

Analysis by gas chromatography-mass spectrometry of pasteurized milk with a fruity (pineapple like) off odour and a sour, rancid and soapy taste indicated the presence of concentrations at microg/ml levels of ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, octanoic acid, decanoic acid and dodecanoic acid. The off-odour and taste were attributed to the presence of these compounds in the milk. Microbiological examination confirmed that the milk was also contaminated with a series of psychrotrophic bacteria including Yersinia intermedia, Pseudomonas putida and Rahnella aquatilis. Growth of isolates of these bacteria in UHT milk at 23 degrees C for 7 d showed that Yer. intermedia produced significant quantities of the C4-C12 alkanoic acids; Ps. putida produced only small quantities of these acids and Rah. aquatilis produced none. In addition, Yer. intermedia and Ps. putida also produced small but significant quantities of the corresponding ethyl esters. In milk inoculated with both Yer. intermedia and Ps. patida, the quantity of ethyl esters produced was greater than that found in cultures containing only one of the isolates. These studies indicated that Yer. intermedia was the principal source of the alkanoic acids in the tainted milk and that the major producer of the corresponding ethyl esters was Ps. patida. This is the first report that Yer. intermedia and Ps. putida can cause an off-odour or taste in dairy products.

Using evidence to make decisions

Physicians sometimes question whether evidence-based medicine "is worth it." They rightfully feel they have been doing a pretty good job right along. This does indeed seem to be the case. Yet the world of medicine is changing rapidly--perhaps too rapidly for our previous habits to suffice. Resources are increasingly restricted even while technology grows explosively--the time, money, and availability of tests and treatments are no longer infinite. If we are to fight for the best decisions for our patients, we must be prepared to support our decisions with more than just opinions and anecdotes. The importance of medical ethics, common sense, and spirituality will not diminish for all this; indeed it may be enhanced as growing consensus on the evidence allows us to focus on the "non-evidence" aspects of our practices. The authors of this special issue of the Wisconsin Medical Journal hope that the concepts we have discussed will convince you to learn more about the important discipline of evidence-based medicine. It is an exciting paradigm for medicine in the coming millennium.

ETA and ETB receptor antagonists synergistically increase extracellular endothelin-1 levels in primary rat astrocyte cultures

Astrocytes produce and bind endothelins (ETs), suggesting that these cells have ET autoregulatory and eliminatory functions. To further investigate these functions in primary rat astrocytes, ET-1 levels in the cell culture media (RIA/HPLC) and intracellular content of ET-1 mRNA (RT PCR) were measured under basal and stimulated (thrombin, 2.2 U/ml) conditions in the presence and absence of ETA and ETB selective antagonists (BQ123 or LU135252, and BQ788, respectively). Neither basal nor stimulated ET-1 levels in astrocyte media were influenced by ETA or ETB antagonists alone, but were significantly increased by a combination of both. ir ET-3 levels were not affected by antagonist treatment. Exogenous ET-1, added to the cultures, was rapidly cleared from the supernatant; this clearance was markedly inhibited by a combination of BQ123 and BQ788. ET-1 mRNA levels were not altered by any treatment. To conclude, in primary rat astrocyte cultures, extracellular ET-1 is cleared by binding to ET-receptors, apparently involving both, ETA and ETB sites. Thus, a blockade of the astrocytic ET eliminatory function as a consequence of the in vivo application of non-selective ET receptor antagonists may lead to increased extracellular ET levels in the brain.

ET(A) and ET(B) specific ligands synergistically antagonize endothelin-1 binding to an atypical endothelin receptor in primary rat astrocytes

Using a whole-cell binding procedure with long incubations at low temperature and subsequent acid stripping, we have characterized an atypical endothelin (ET) receptor in primary rat cortical astrocyte cultures. We found the following: (a) no competition for 125I-ET-1 binding by the ET(A) antagonists BQ-123 and LU 135252 or the ET(B) agonist IRL 1620; (b) weak competition by the ET(B) antagonist BQ-788 and by the predominant ET(B) ligand ET-3; (c) potent synergistic competition of ET(A) and ET(B) ligands in combination for 125I-ET-1 binding; (d) potent competition of ET-1 with any of the radioligands used, 125I-ET-1, 125I-IRL 1620, and [3H]BQ-123; (e) lack of competition of IRL 1620 and BQ-123 with the respective other radioligand; (f) shifting of the amount of acid-strippable 125I-ET-1 binding from 20 to 80% by ET(B) ligands and to 4% by ET(A) ligands; and (g) as a control, typical ET(A) and ET(B) binding characteristics of the RAT-1 fibroblast and the U373MG astrocytoma cell line, respectively, under our assay conditions. The unusual binding properties of astrocytic ET receptors described in this study appear to be the result of several binding sites in the receptor for different ET ligands or ligand epitopes.

Early attachment of leucocytes, platelets and fibrinogen in endothelial cell-seeded Dacron venous conduits

BACKGROUND

There is a need for prosthetic venous conduits in surgery for trauma, cancer and thrombotic disease. Such conduits in use today have a low patency rate, leaving room for much improvement.

METHODS

This experimental study investigated the dynamics of the early attachment of radiolabelled platelets, leucocytes and fibrinogen to endothelial cell-seeded Dacron venous conduits in sheep. Grafts were placed as jugular vein interposition grafts, seeded on one side, not seeded on the other, and followed for 4 h.

RESULTS

No difference could be demonstrated between the two graft types. Platelets showed an increasing attachment during the whole period, leucocytes an immediate attachment followed by an undulating pattern, and fibrinogen an immediate attachment with a tendency to decrease. Measurements on the vein itself showed a high attachment and, for platelets, an extremely high attachment when measured after the graft in the direction of flow.

CONCLUSION

The seeding process did not seem to affect early thrombogenicity. The carefully dissected vein wall showed highly thrombogenic properties, in many ways as high as in the prosthetic graft.

Early attachment of platelets, leukocytes, and fibrinogen in endothelial cell seeded Dacron grafts

Endothelial cell seeding has been advocated as a method for reducing the thrombogenicity of prosthetic grafts. Principally two different techniques for endothelial cell seeding can be used: immediate seeding of grafts followed by implantation or initial growth and establishment of an endothelial cell-covered surface before subsequent late implantation. This study was designed to determine whether the immediate seeding technique altered thrombogenicity directly after graft implantation. Carotid arteries from 19 sheep were replaced with Dacron interposition grafts; one side was seeded with endothelial cells and the other side was left unseeded. The dynamics of thrombus formation involving radiolabeled platelets, leukocytes, and fibrinogen were studied for 4 hours with flow reduced to 35 ml/min. No difference in platelet uptake (approximately 6-fold increase compared to baseline values) was found between endothelial cell seeded and unseeded grafts. Likewise, there were no differences in leukocyte uptake (approximately 4-fold increase) or fibrinogen uptake (approximately 10- to 15-fold increase) between the two groups. No differences were demonstrated with regard to patency or thrombus weight. In this experimental investigation we were unable to verify any change in the uptake of platelets, white blood cells, or fibrinogen between endothelial cell seeded and unseeded Dacron grafts during the first 4 hours after graft placement. Immediate seeding does not affect the initial thrombogenicity of grafts.

Recovery of endothelial cells and prostanoid production in endothelial cell-seeded grafts

OBJECTIVE

To investigate the function and morphology of endothelial cell (EC) seeded grafts.

DESIGN

Experimental, open study.

CHIEF OUTCOME MEASURES

Endoluminal release of prostacyclin (6-Keto-PGF1 alpha) and thromboxane B2 (TxB2), patency, EC coverage and cell identity.

MATERIALS

In 12 sheep, segments of both carotid arteries were excised. On one side a seeded and on the other an unseeded dacron graft were inserted. After 3 months the grafts were excised. In grafts and arteries, the endoluminal release of 6-keto-PGF1 alpha and TxB2 was determined in a perfusion system. Scanning electron microscopy (SEM) and light microscopy were used to determine the EC coverage and cell identity.

RESULTS

Eight animals survived. Three seeded and two unseeded grafts were occluded. Prostacyclin release did not differ significantly between seeded and unseeded grafts and arteries, when the arteries were looked upon as one group. When the graft was compared with its corresponding artery, i.e. the artery it replaced, a significantly lower release was found in the unseeded group. Thromboxane release was undetectable in arteries but significantly higher in both graft groups. SEM revealed a cellular coverage of 75% in the seeded grafts and 50% in the unseeded (not significant). Light microscopy showed a patchy staining for Factor VIII-related antigen in some grafts in both groups.

CONCLUSION

Prostacyclin release in unseeded and seeded dacron grafts did not differ 3 months after implantation in sheep, except when the graft was compared with its corresponding artery. The significance of this remains to be settled. Seeded grafts did not have a higher proportion of endothelial coverage than unseeded grafts.

In vitro attachment of endothelial cells to different graft materials

The purpose of this study was to compare the degree of endothelial cell attachment to different synthetic vascular graft materials. Human microvessel endothelial cells were labelled with indium-111-oxine, injected into 9 different vascular grafts and left to adhere for 40 min. Unattached cells were removed and radioactivity of the grafts measured. Grafts were flushed with 20 ml phosphate-buffered saline during 5 s to remove cells with poor attachment and radioactivity was measured again. Attachment differed between the grafts. In order of decreasing attachment the grafts were albumin-coated Dacron (47%), preclotted Dacron (35-44%), gelatin-coated Dacron (20%), gelatin-coated polyurethane (17%), collagen-coated Dacron (12%), preclotted expanded polytetrafluoroethylene (ePTFE; 3%). Albumin-coated Dacron showed the highest degree of cell attachment of ePTFE the lowest. Statistically significant differences exist between ePTFE and all other grafts and between albumin-coated and collagen-coated Dacron, gelatin-coated polyurethane and gelatin-coated Dacron.

Loss of seeded endothelial cells in vivo. A study of Dacron grafts under different flow conditions

OBJECTIVES

To assess, in vivo, the loss of endothelial cells seeded in a Dacron graft at low, restricted arterial flow and at normal unrestricted flow.

DESIGN AND SETTING

Laboratory animal study.

MATERIALS

Indium-111-oxine labelled endothelial cells were seeded in externally supported, preclotted Dacron grafts, inserted as interposition grafts in the carotid arteries of nine sheep. Activity (radioactivity) was measured, flow established, on one side unrestricted 120-180 ml/minute, and on the other restricted to 50 ml/minute by a distal clamp.

OUTCOME MEASURES

The reduction in activity over the grafts was measured for 2 hours.

RESULTS

There was an immediate loss of activity to around 80% and thereafter a lower rate of cell loss to around 50%. No difference could be demonstrated in the loss from low flow compared to high flow grafts. All grafts were patent. There was no difference in thrombus weights.

CONCLUSION

No difference could be demonstrated in seeded endothelial cell loss from a Dacron graft in vivo at low flow (50 ml/minute) compared with unrestricted flow (120-180 ml/minute).

Endothelial cell seeded dacron aortobifurcated grafts: platelet deposition and long-term follow-up

OBJECTIVE

The prospect of seeding endothelial cells to a prosthetic graft has been successful in the experimental setting, but less convincing in clinical studies in humans. This study was performed with the objective of evaluating endothelial cell seeding of aorto-bi-iliofemoral reconstructions with cells harvested at the same procedure.

EXPERIMENTAL DESIGN

Randomized study with one graft limb seeded and with at least 5 year follow-up.

SETTING

University Hospital.

PATIENTS

15 patients undergoing aorto-bi-ilio-femoral reconstruction.

INTERVENTIONS

One graft limb (randomly determined) was seeded with autologous endothelial cells (median 5.2 x 10(5)) enzymatically (Dispase II) harvested from the saphenous vein (length 8-15 cm, diameter 4-8 mm). The other graft limb served as a control.

MEASURES

Two months after surgery platelets were labelled with 111In and platelet activity registered over the graft. Long-term outcome were followed (median 5 years and 10 months).

RESULTS

No difference in platelet activity was noted between the seeded and non-seeded graft limb. Different techniques of calculating graft wall activity showed large interindividual variations in the results. Long-term outcome showed that three patients died, two from myocardial infarction on postoperative day three and 60, and one patient died four years after surgery from a lung cancer. Grafts functioned well. In one non-seeded graft limb the patient had severe microembolisation postoperatively that required amputation 10 days after surgery. Of seeded graft limbs one occluded 42 months after surgery, intimal hyperplasia at the distal anastomosis was seen and in one patient progress of arteriosclerosis required additional surgery 12 months after initial operation with profundaplasty (partly due to intimal hyperplasia) and later two additional femoro-distal reconstructions were needed.

CONCLUSION

In summary with our single-staged technique for seeding of endothelial cells to a graft limb in a high flow situation no effect on platelet activity at two months was found and long-term outcome was not obviously influenced.

Short AV interval VDD pacing does not prevent tilt induced vasovagal syncope in patients with cardioinhibitory vasovagal syndrome

Eleven subjects (mean age 50 years, range 33-71 years), who had previously received permanent dual chamber pacemakers for cardioinhibitory vasovagal syncope, underwent paired Westminster protocol tilt tests, one with short AV delay VDD pacing and one without pacing, to test the hypothesis that continuous ventricular pacing would prevent the cardiac initiation of vasovagal syncope. Nine (82%) of the paced tilts produced positive vasovagal outcomes compared with seven (64%) of the unpaced tilts. No important differences in the heart rate or blood pressure behavior during tilt or the time to positive vasovagal outcomes were observed between the paired tilts. There was more accelerated syncope/presyncope once symptoms had developed during the paced tilts of subjects in whom both study tilts were positive, although this did not reach statistical significance (P = 0.054). This study shows that atrial synchronous ventricular pacing does not prevent the initiation, or progression, of tilt induced vasovagal syncope in predisposed subjects.

Prostacyclin is produced from endothelial cell-seeded grafts: an experimental study in sheep

Endothelial cell seeding might be of value in reducing the thrombogenicity of small-diameter vascular grafts. We investigated the capacity of endothelial cell-seeded grafts to produce prostacyclin and compared this with that of the unseeded graft as well as the native artery. Twelve sheep were operated on with carotid interposition of externally supported knitted dacron grafts. On one side of the neck the graft was seeded with endothelial cells, enzymatically harvested from the left jugular vein. After 3 weeks, three out of 12 seeded grafts, and one out of 12 unseeded grafts were occluded (N.S.). After excision, the grafts were mounted and perfused ex vivo for five 15-min periods. During the last period, arachidonic acid (4 micrograms/ml) was added to the perfusate. The resected carotid artery was used as a control. Prostacyclin was determined as the stable degradation product 6-keto-PGF1 alpha using radio-immunoassay, and expressed as pg mm-2 luminal surface. The native artery had a significantly higher release of prostacyclin than the seeded graft, which in turn had a significantly higher release than the unseeded graft. Histological examination showed weakly positive staining for factor VIII-related antigen on the luminal surface of seeded grafts. Scanning electron microscopy showed endothelial cells with typical endothelial tufts and was evaluated blindly from 10 areas of each graft. The extent of endothelial cell coverage was evaluated and scored from 0 to 2.5. The median score for the unseeded grafts was 0.3 and for the seeded grafts 1.5 (p = 0.008). Prostacyclin production was higher in seeded than unseeded grafts, but did not influence patency in this model.

Does dextran 40 reduce early graft thrombogenicity? An experimental investigation on patency and platelet deposition on prosthetic graft materials in sheep

The mechanism by which dextran 40 reduces early graft thrombogenicity has not been fully elucidated. Dextran improves haemaodynamics, reduces platelet aggregation, alters fibrin formation and enhances thrombus lysis. In this experimental investigation on sheep using a low flow model, the thrombogenicity of various grafts was studied when either a dextran or saline infusion was given. Bilateral carotid interposition grafts with expanded polytetrafluorethylene (ePTFE) on one side and dacron on the other (random allocation) were inserted in 12 sheep. The sheep were randomly divided into two groups, one given a dextran infusion and the other saline. A tendency for improved graft patency was seen in the dextran 40 treated animals (P less than 0.05 at 3 h). However, platelet accumulation did not differ markedly between the dextran 40 and saline treated groups. On the other hand there was a clear reduction of platelet accumulation on ePTFE grafts compared to dacron grafts (P less than 0.01). A large part of the radioactivity measured from the dacron graft was located within the graft wall. Further studies to clarify the mechanism of action of dextran are needed.

Analysis of the regulatory region of the Escherichia coli nupG gene, encoding a nucleoside-transport protein

The S1-mapping procedure, when applied to an 800-bp fragment upstream of the nupG structural gene of Escherichia coli revealed one transcription-initiation site. The corresponding promoter is negatively regulated by the cytR and the deoR repressors. The expression of the gene is activated by the complex between cAMP and its receptor protein. In strains lacking cAMP the promoter expression is reduced and it is no longer regulated by the cytR repressor, whereas the deoR regulation is retained.

Heparinization of polytetrafluoroethylene (ePTFE) grafts. The effect on pseudointimal hyperplasia

A study was undertaken to evaluate the effect of a covalent heparinization on thrombogenicity of ePTFE grafts in sheep. With scanning electron microscopy heparinization occurred as a thin smooth layer covering the network of ePTFE. Most of it had disappeared already after 2 hours. In long-term experiments a high and low flow part of the ePTFE graft was created in the carotid artery system. The heparinization had no effect on patency and there was no difference between the high and low flow parts of the graft. The graft surface was covered with fibrous tissue, which was significantly thicker than the pannus in the host vessel. In the graft interstices (internodal distance of 30 micron) capillaries were seen without difference between occluded and patent grafts. The capillary density was significantly higher proximally than distally.