Metformin, Microbiome and Protection Against Colorectal Cancer

Metformin is widely used as a firstline therapy to improve insulin sensitivity in type 2 diabetes mellitus (T2DM) patients. This is achieved primarily through regulating AMP-activated protein kinase (AMPK)-dependent pathways leading to reduced hepatic gluconeogenesis and improved muscular uptake of glucose. Epidemiological studies first recognized a relationship with metformin use in T2DM patients and reduced colorectal cancer (CRC) risk. Thereafter, metformin has gained wide attention as a candidate CRC chemopreventative agent; however, the molecular mechanisms underlying its gastrointestinal anti-cancer properties appear multi-faceted and are not well understood. An intriguing area of research is the growing evidence of metformin's metabolic juncture with gut microbiota at the intestinal mucosal interface. This review examines the mechanistic evidence which may account for metformin's protection against CRC through interactions between the drug, gut microbiota and the colonic epithelial mucosa.

Age and sex-related decline of muscle strength across the adult lifespan: a scoping review of aggregated data

Muscle strength is sex-related and declines with advancing age; yet, a comprehensive comparative evaluation of age-related strength loss in human females and males has not been undertaken. To do so, segmented piecewise regression analysis was performed on aggregated data from studies published from 1990 to 2018 and are available in CINAHL, EMBASE, MEDLINE, and PsycINFO databases. The search identified 5613 articles that were reviewed for physical assessment results stratified by sex and age. Maximal isometric and isokinetic 60°·s^-1 knee extension (KE) and knee flexion (KF) contractions from 57 studies and 15 283 subjects (N = 7918 females) had sufficient data reported on females and males for meaningful statistical evaluation to be undertaken. The analysis revealed that isometric KE and KF strength undergo similar rapid declines in both sexes late in the sixth decade of life. Yet, there is an abrupt age-related decline in KE 60°·s^-1 peak torque earlier in females (aged 41.8 years) than males (aged 66.7 years). In the assessment of KF peak torque, an age-related acceleration in strength loss was only identified in males (aged 49.3 years). The results suggest that age-related isometric strength loss is similar between sexes while the characteristics of KE and KF peak torque decline are sex-related, which likely explains the differential rate of age-related functional decline. Novelty Inclusion of muscle strength and torque of KE and KF data from >15 000 subjects. Isometric KE and KF strength loss are similar between sexes. Isokinetic 60°·s^-1 KE torque decline accelerates 25 years earlier in females and female age-related KF peak torque decline does not accelerate with age.

Real-world Effectiveness and Safety of Vedolizumab for the Treatment of Inflammatory Bowel Disease: The Scottish Vedolizumab Cohort

BACKGROUND & AIMS

Vedolizumab is an anti-a4b7 monoclonal antibody that is licensed for the treatment of moderate to severe Crohn's disease and ulcerative colitis. The aims of this study were to establish the real-world effectiveness and safety of vedolizumab for the treatment of inflammatory bowel disease.

METHODS

This was a retrospective study involving seven NHS health boards in Scotland between June 2015 and November 2017. Inclusion criteria included: a diagnosis of ulcerative colitis or Crohn's disease with objective evidence of active inflammation at baseline (Harvey-Bradshaw Index[HBI] ≥5/Partial Mayo ≥2 plus C-reactive protein [CRP] >5 mg/L or faecal calprotectin ≥250 µg/g or inflammation on endoscopy/magnetic resonance imaging [MRI]); completion of induction; and at least one clinical follow-up by 12 months. Kaplan-Meier survival analysis was used to establish 12-month cumulative rates of clinical remission, mucosal healing, and deep remission [clinical remission plus mucosal healing]. Rates of serious adverse events were described quantitatively.

RESULTS

Our cohort consisted of 180 patients with ulcerative colitis and 260 with Crohn's disease. Combined median follow-up was 52 weeks (interquartile range [IQR] 26-52 weeks). In ulcerative colitis, 12-month cumulative rates of clinical remission, mucosal healing, and deep remission were 57.4%, 47.3%, and 38.5%, respectively. In Crohn's disease, 12-month cumulative rates of clinical remission, mucosal healing, and deep remission were 58.4%, 38.9%, and 28.3% respectively. The serious adverse event rate was 15.6 per 100 patient-years of follow-up.

CONCLUSIONS

Vedolizumab is a safe and effective treatment for achieving both clinical remission and mucosal healing in ulcerative colitis and Crohn's disease.

Faecal Calprotectin and Magnetic Resonance Enterography in Ileal Crohn's Disease: Correlations Between Disease Activity and Long-Term Follow-Up

BACKGROUND AND AIMS

Magnetic resonance enterography [MRE] is the gold standard for assessing ileal inflammation in Crohn's disease [CD]. The aim of the present study was to correlate faecal calprotectin [FC] to MRE via a simple score in an exclusive ileal cohort with long-term follow-up for association with time to surgery or biologic therapy.

METHODS

In total, 150 MRE studies with matched FC [±30 days] were identified from the Edinburgh FC Register [2008-12; n = 18138]. Scans were re-read blinded to clinical data, independently, by two expert gastrointestinal radiologists, to generate a simple MRE score [range 0-10] from assessment of the worst intestinal segment plus total disease extent.

RESULTS

In total, 119 MRE scans were evaluated from 104 patients with ileal CD [L1 or L3 with panproctocolectomy]. Receiver operating characteristic analysis showed an area under the curve of 0.77 [0.67-0.87, p < 0.0001] for FC and MRE score >1, with an optimal cut-off of 145 μg/g for severe inflammation on MRE with 69.3% [57.6-79.5] sensitivity and 71.4% [53.7-85.4] specificity. Long-term follow-up over a median [interquartile range] of 2086 days [1786-2353] revealed FC ≥ 145 μg/g was associated with reduced biologic-free survival until 3 years following MRE, whereas MRE score [severe vs absent] was associated with reduced surgery- and biologic-free survival throughout follow-up. Backwards stepwise logistic regression revealed that length of ileal disease (odds ratio [OR] 3.8, 1.1-13.2, p = 0.034) and increased bowel wall thickness at MRE [OR 4.2, 1.6-10.7, p < 0.0001] or female sex [OR 5.2, 1.5-18.7, p = 0.011] increased the risk of biologic use or surgery, respectively.

CONCLUSIONS

FC correlates well with MRE assessment of ileal CD with MRE parameters associated with long-term biologic- and surgery-free remission.

Chromatic techniques for in vivo monitoring jaundice in neonate tissues

OBJECTIVE

A chromatic method is described for providing a preliminary indication of unacceptable bilirubin levels in a newly born baby in order to avoid the development of serious mental deficiencies. The aim was to investigate the reliability of a new chromatic approach using a novel template unit for a preliminary, non-invasive monitoring of the skin tissue of newly born babies with jaundice and its capability for use with different mobile phone cameras.

APPROACH

A description of the monitoring system is given along with an explanation of the monitoring technique used. Preliminary tests have been performed on 48 different neonates each being addressed by one of six different mobile phone cameras, which were randomly available to the operating clinicians.

MAIN RESULTS

The test results have a correlation (R ²) of 0.81, a sensitivity (Sn) of 0.97, a specificity (Sp) of 0.82, a positive predictive value (PPV) of 0.95 and a negative predictive value (NPV) of 0.9.

SIGNIFICANCE

The significance of the results obtained is that they show the approach to have a high level of fail-safe reliability in indicating the bilirubin levels when compared with blood test results. The results also show that the approach can be used with a few different mobile phone cameras and that because of its non-invasive nature and its cost effectiveness, has the potential for remote use from a medical hospital to provide an immediate preliminary diagnosis.

Cancer Therapy: Phenothiazines in an Unexpected Role

Four lines of evidence (clinical findings, epidemiology, inhibition of tumor growth together with prolongation of survival time, and mechanism of action) which suggest that certain phenothiazines, particularly chlorpromazine, possess a range of anti-neoplastic activities in man and in rodents which has not been generally recognised are reviewed and discussed. Chlorpromazine interferes with energy production in sensitive tumours; the mode of action appears to correspond to autooxidative cellular injury, a common form of cell death.

Stretch training induces unequal adaptation in muscle fascicles and thickness in medial and lateral gastrocnemii

This study compared adaptations in fascicle lengths, pennation angles, and muscle thickness of the lateral and medial gastrocnemii in response to 6 weeks of stretch training. The nondominant plantar flexors of 11 males were stretched five times per week for 6 weeks and compared with the contralateral leg and a nonstretched control group of 10 males. During stretch training, instantaneous electromyography was utilized to ensure passive muscle stretch. At baseline, week three, week six and 1 week after the conclusion of stretch training, ultrasound was used to measure fascicle lengths, pennation angles, muscle thickness of the lateral gastrocnemius and medial gastrocnemius, and Achilles tendon thickness and length. Plantar flexion torque was measured, and voluntary activation was assessed. Muscle thickness increased 5.6% after 6 weeks of stretch training (P=.009). The fascicles in the lateral gastrocnemius lengthened to a greater extent than the medial. Overall, fascicles lengthened 25% (P<.001) in the muscle tendon junction and 5.1% (P<.001) in the muscle belly. Pennation angles were unchanged in the medial gastrocnemius but decreased in the lateral gastrocnemius 7.1% (P=.02). There was no change in maximal voluntary contraction, voluntary activation, tendon length, or thickness. This study demonstrates that stretch training is a viable modality to alter muscle architecture of the human gastrocnemius through lengthening of muscle fascicles, decreasing pennation angles, and increasing muscle thickness, albeit adaptations are unequal between the lateral and medial heads.

Concurrence of Frailty and Parkinson's Disease

BACKGROUND

Females with Parkinson's disease (PD) are at greater risk of frailty than males. Little is known about how age and disease-related characteristics influence frailty in females with PD because frailty studies often exclude persons with underlying neurological pathologies.

OBJECTIVE

To determine age and disease-related characteristics that best explain physical frailty in community-dwelling females with and without PD.

DESIGN AND MEASUREMENT

Correlation coefficients described relationships between PD-related characteristics and physical frailty phenotype criteria (Cardiovascular Health Study). Regression analysis identified associations between disease-related characteristics and frailty in non-PD and PD females.

SETTING

Community-dwelling.

PARTICIPANTS

Females with mild to moderate PD (n = 17, mean age = 66 ± 8.5 years) and non-PD (n = 18, mean age = 72 ± 13.2 years) participated.

RESULTS

Daily carbidopa-levodopa dose best explained frailty in PD females (β = 0.5), whereas in non-PD females, age (β = 0.7) and comorbidity (β = 0.5) were most associated with frailty.

CONCLUSIONS

Dopaminergic medication explained frailty in PD and not measures of disease progression (i.e. severity, duration). In females without PD age-related accumulation of comorbidities resulted in greater risk of frailty. This indicates dopaminergic management of PD symptoms may better reflect frailty in females with PD than disease severity or duration. These data suggest the influence of underlying frailty should be considered when managing neurological conditions. Understanding how frailty concurrently exists with PD and how these conditions progress within the aging female will facilitate future care management.

How Do Community Physical and Occupational Therapists Classify Frailty? A pilot Study

BACKGROUND

Frailty is a complex geriatric syndrome that is often difficult to diagnose, especially by healthcare professionals working in the community. Objectives, Measurements: This study examined how physical and occupational therapists classified community-dwelling clients using categories of 'nonfrail', 'prefrail' or 'frail' as compared to measurements of established frailty criteria from the Cardiovascular Health Study frailty index (CHSfi).

RESULTS

Results indicate that community therapists underestimate frailty in comparison to the CHSfi. Therapists' classification of frailty suggested their perceptions of frailty may not only relate to client's functional capacity, but the context in which the client receives care.

CONCLUSION

A multi-dimensional approach is required to capture all aspects of frailty across the healthcare continuum that accounts for how the client thrives within their personal environment.

Systematic review: The use of thiopurines or anti-TNF in post-operative Crohn's disease maintenance--progress and prospects

BACKGROUND

Post-operative recurrence of Crohn's disease is an important management challenge, with 2-year recurrence rates defined by clinical, endoscopic and radiological parameters of up to 77%, 64% and 49%. Clinical and severe endoscopic recurrence vary widely in controlled trials from 13% to 36% and 22% to 56% with thiopurine treatment or 0% and 9% with infliximab treatment respectively at 1 year.

AIMS

To provide a review of the evidence for thiopurine or anti-TNF use in post-operative Crohn's disease, and to assess the ability to identify those patients at highest risk of recurrent disease.

METHODS

A literature search was undertaken using Medline, Embase and Cochrane databases to identify studies using search terms 'thiopurine', 'azathioprine', 'mercaptopurine', 'Infliximab', 'adalimumab', 'Anti-TNF', 'Crohn's disease', 'post-operative' and 'recurrence'.

RESULTS

Trials to examine this important area have proved difficult to execute, with recruitment and retention of patients posing major challenges to randomised clinical trials. There have been four RCTs of 433 patients of thiopurine therapy (with three meta-analyses of these data), and one of anti-TNF therapy involving 24 patients. Overall the efficacy data for thiopurine use in this setting are inconclusive, and other than smoking, there are no consistent predictors of post-operative relapse.

CONCLUSIONS

At present, evidence for routine use of thiopurine treatment in post-operative Crohn's disease is heterogeneous and unconvincing. Stratification by risk of relapse emerges as a key challenge in post-operative management that needs to be addressed, using clinical parameters and emerging biomarkers. The evidence for prophylactic anti-TNF use is limited though promising, with its routine use guided by early assessment of relapse.

Precision high-value resistance scaling with a two-terminal cryogenic current comparator

We describe a cryogenic two-terminal high-resistance bridge and its application in precision resistance scaling from the quantized Hall resistance (QHR) at RH = RK/2 = 12 906.4035 Ω to decade resistance standards with values between 1 MΩ and 1 GΩ. The design minimizes lead resistance errors with multiterminal connections to the QHR device. A single variable voltage source and resistive ratio windings are utilized to achieve excellent dynamic stability, which is not readily obtained in low-current measurements with conventional cryogenic current comparators (CCCs). Prototypes of this bridge have been verified by a successful international comparison of high-resistance scaling using two-terminal CCCs in the national metrology institutes of Argentina, Mexico, and the United States.

Impact of antibiotic treatment for pulmonary exacerbations on bacterial diversity in cystic fibrosis

BACKGROUND

A diverse array of bacterial species is present in the CF airways, in addition to those recognised as clinically important. Here, we investigated the relative impact of antibiotics, used predominantly to target Pseudomonas aeruginosa during acute exacerbations, on other non-pseudomonal species.

METHODS

The relative abundance of viable P. aeruginosa and non-pseudomonal species was determined in sputa from 12 adult CF subjects 21, 14, and 7 days prior to antibiotics, day 3 of treatment, the final day of treatment, and 10-14 days afterwards, by T-RFLP profiling.

RESULTS

Overall, relative P. aeruginosa abundance increased during antibiotic therapy compared to other bacterial species; mean abundance pre-antibiotic 51.0±36.0% increasing to 71.3±30.4% during antibiotic (ANOVA: F(1,54)=5.16; P<0.027). Further, the number of non-pseudomonal species detected fell; pre-antibiotic 6.0±3.3 decreasing to 3.7±3.3 during treatment (ANOVA: F(1,66)=5.11; P<0.027).

CONCLUSIONS

Antibiotic treatment directed at P. aeruginosa has an additional significant impact on non-pseudomonal, co-colonising species.

Audit of acute Charcot's disease in the UK: the CDUK study

AIMS/HYPOTHESIS

We studied factors associated with the development and resolution of acute Charcot foot using a web-based observational study.

METHODS

Clinicians managing cases of acute Charcot foot in the UK and Ireland between June 2005 and February 2007 were invited to register anonymised details on a secure website.

RESULTS

A total of 288 cases (age 57.0 ± 11.3 years [mean ± SD]; 71.2% male) were registered from 76 centres. Of these, 36% of patients recalled an episode of relevant trauma in the preceding 6 months, while 12% had had surgery to the affected foot. In 101 (35%) cases, ulceration was present at registration and 20% of these had osteomyelitis. Non-removable off-loading devices were used at presentation in 35.4% of cases, with removable off-loading used in 50%. Data on resolution were available for 219 patients. The median time to resolution was 9 months in patients whose initial management included the use of non-removable off-loading, compared with 12 months in the remainder (p = 0.001). Bisphosphonates were administered intravenously in 25.4% and orally in 19.4% of cases. The median time to resolution in patients who received bisphosphonates was 12 months and was longer than in those who did not (10 months, p = 0.005).

CONCLUSIONS/INTERPRETATION

The median time to resolution was longer than in earlier series. Although limited by being observational and non-randomised, these data suggest that the use of non-removable off-loading at presentation may shorten the time to resolution. They provide no evidence to indicate that the use of bisphosphonates is beneficial.

Comparison of extraction of a β-blocker from plasma onto a molecularly imprinted polymer with liquid–liquid extraction and solid phase extraction methods

An optimised solid phase extraction (SPE) method developed for the extraction of a structural analogue of the beta-blocking drug propranolol from plasma utilising a molecularly imprinted polymer (MIP) has been compared with methods based on conventional liquid-liquid extraction (LLE), and SPE using C18-bonded and immobilised phenyl boronic acid (PBA). All four methods could be used for the extraction of the analyte with acceptable accuracy and precision. The MIP-based method, unlike the other methods required a protein precipitation step prior to extraction to eliminate the effects of co-extracted protein. The best performance was seen with the LLE method followed by SPE on the C18 phase. The MIP-based method represented no advantage over the comparator methods for this analyte. Indeed the performance of the MIP-based method was marginally worse as leaching of low level template impurities prevented detection of the target analyte at low concentrations (5 ngmL(-1)). This relatively poorer performance was evident as worse accuracy at low concentrations with a consequent higher limit of quantification than the conventional methods.

Passive immunization of rainbow trout, Oncorhynchus mykiss (Walbaum), against Flavobacterium psychrophilum, the causative agent of bacterial coldwater disease and rainbow trout fry syndrome

Flavobacterium psychrophilum, the causative agent of bacterial coldwater disease (CWD) and rainbow trout fry syndrome (RTFS), causes high mortality in cultured salmonids. The present study was designed to determine the role antibody plays in conferring protection to rainbow trout fry, Oncorhynchus mykiss (Walbaum), by passive immunization with convalescent serum or serum from adult rainbow trout immunized with F. psychrophilum, and goat anti-F. psychrophilum serum. In each experiment, rainbow trout fry were injected intraperitoneally with antiserum and challenged by subcutaneous injection with a virulent strain (CSF-259-93) of F. psychrophilum 24-h post-immunization. Relative percentage survival (RPS) ranged from 9-42% when rainbow trout fry (mean weight 1.3 g) were injected with a 1:2 dilution of 25 microL of convalescent serum ranging in enzyme-linked immunosorbent assay antibody titres from 1600-102400. Rainbow trout fry (mean weight 1.0 g) passively immunized with 25 microL of serum from immunized adult fish exhibited RPS values of up to 57%. In each of these experiments, RPS increased with increasing antibody titres against F. psychrophilum. Passive immunization with 25 or 50 microL goat anti-F. psychrophilum serum, however, did not confer protection to fry (mean weight 1.3 g). These results suggest that trout antibody plays a role in conferring protection to F. psychrophilum, but antibody alone is unable to provide complete protection.

Structure, stability and folding of the alpha-helix

Pauling first described the alpha-helix nearly 50 years ago, yet new features of its structure continue to be discovered, using peptide model systems, site-directed mutagenesis, advances in theory, the expansion of the Protein Data Bank and new experimental techniques. Helical peptides in solution form a vast number of structures, including fully helical, fully coiled and partly helical. To interpret peptide results quantitatively it is essential to use a helix/coil model that includes the stabilities of all these conformations. Our models now include terms for helix interiors, capping, side-chain interactions, N-termini and 3(10)-helices. The first three amino acids in a helix (N1, N2 and N3) and the preceding N-cap are unique, as their amide NH groups do not participate in backbone hydrogen bonding. We surveyed their structures in proteins and measured their amino acid preferences. The results are predominantly rationalized by hydrogen bonding to the free NH groups. Stabilizing side-chain-side-chain energies, including hydrophobic interactions, hydrogen bonding and polar/non-polar interactions, were measured accurately in helical peptides. Helices in proteins show a preference for having approximately an integral number of turns so that their N- and C-caps lie on the same side. There are also strong periodic trends in the likelihood of terminating a helix with a Schellman or alpha L C-cap motif. The kinetics of alpha-helix folding have been studied with stopped-flow deep ultraviolet circular dichroism using synchrotron radiation as the light source; this gives a far superior signal-to-noise ratio than a conventional instrument. We find that poly(Glu), poly(Lys) and alanine-based peptides fold in milliseconds, with longer peptides showing a transient overshoot in helix content.

Massive hepatosplenomegaly caused by Penicillium marneffei associated with human immunodeficiency virus infection in a Thai patient

A 29 year old Thai woman presented with non-specific features and examination revealed left upper zone consolidation and hepatosplenomegaly. The initial clinical differential diagnosis included tuberculosis and melioidosis. She died four days after admission, while still under investigation. Postmortem examination revealed antibodies to human immunodeficiency virus, disseminated Penicillium marneffei infection, and Salmonella enteritidis infection. Penicillium marneffei is a well described AIDS defining pathogen in South East Asia but is very rare in the UK. Appropriate antifungal treatment may be associated with a successful outcome. Increased awareness of this clinical association may enable correct diagnosis in affected patients from South East Asia presenting within the UK.

Stabilizing nonpolar/polar side-chain interactions in the alpha-helix

A simplistic, yet often used, view of protein stability is that amino acids attract other amino acids with similar polarity, whereas nonpolar and polar side chains repel. Here we show that nonpolar/polar interactions, namely Val or Ile bonding to Lys or Arg in alpha-helices, can in fact be stabilizing. Residues spaced i, i + 4 in alpha-helices are on the same face of the helix, with potential to favorably interact and stabilize the structure. We observe that the nonpolar/polar pairs Ile-Lys, Ile-Arg, and Val-Lys occur in protein helices more often than expected when spaced i, i + 4. Partially helical peptides containing pairs of nonpolar/polar residues were synthesized. Controls with i, i + 5 spacing have the residues on opposite faces of the helix and are less helical than the test peptides with the i, i + 4 interactions. Experimental circular dichroism results were analyzed with helix-coil theory to calculate the free energy for the interactions. All three stabilize the helix with DeltaG between -0.14 and -0.32 kcal x mol(-1). The interactions are hydrophobic with contacts between Val or Ile and the alkyl groups in Arg or Lys. Side chains such as Lys and Arg can thus interact favorably with both polar and nonpolar residues.

The incidence of hematuria in middle distance track running

The purpose of this study was to establish if middle distance track athletes experience hematuria during their competitive season interval workouts and, if so, what type of workout based on intensity and distance was most associated with hematuria. During a 4-week observational period, athletes (n = 10) underwent reagent strip urinalysis before and after their twice weekly interval sessions. Positive samples for hematuria were analyzed microscopically to accurately determine red blood cell (RBC) loss. Seventy-one individual interval workouts were observed, of which 32 cases of hematuria were reported. Nine cases of hematuria exhibited >100 RBC per High Power Field (Hpf). Furthermore, 90% of the athletes experienced post-workout hematuria at least once. The highest incidence of hematuria was observed after workouts run at 110% of VO(2peak) over short (600-1,500 m) to moderate (1,501-3,000 m) distances. All post-exercise cases of hematuria resolved within 2 hr of recovery.

Protection of rainbow trout against infectious hematopoietic necrosis virus four days after specific or semi-specific DNA vaccination

A DNA vaccine against a fish rhabdovirus, infectious hematopoietic necrosis virus (IHNV), was shown to provide significant protection as soon as 4 d after intramuscular vaccination in 2 g rainbow trout (Oncorhynchus mykiss) held at 15 degrees C. Nearly complete protection was also observed at later time points (7, 14, and 28 d) using a standardized waterborne challenge model. In a test of the specificity of this early protection, immunization of rainbow trout with a DNA vaccine against another fish rhabdovirus, viral hemorrhagic septicemia virus, provided a significant level of cross-protection against IHNV challenge for a transient period of time, whereas a rabies virus DNA vaccine was not protective. This indication of distinct early and late protective mechanisms was not dependent on DNA vaccine doses from 0.1 to 2.5 microg.

(Z)-3-hexenyl (R)-3-hydroxybutanoate: a male specific compound in three North American decorator wasps Eucerceris rubripes, E. conata and E. tricolor

The males of the decorator wasps Eucerceris have been observed to display abdomen-dragging behavior on plants surrounding their nest. It is thought that this applies a territorial-marking sex pheromone that serves to alert females to the males' territory for courtship and mating. The extracts of three species E. rubripes, E. conata, and E. tricolor have been analyzed by GC-MS. The gas chromatograms revealed the presence, in large quantities, of one common volatile compound in the male head extracts. By analogy with the closely related bee wolves Philanthus, we believe the pheromone is produced in the mandibular glands. Utilizing mass spectrometry, microreactions, FT-IR, and 1H and 13C NMR spectroscopy the structure of the pheromone was proposed to be (Z)-3-hexenyl 3-hydroxybutanoate, which was confirmed by synthesis. The absolute configuration of the chiral center was determined to be R for the three species by preparing the Mosher esters of the insect samples and comparing their GC retention times with a synthetic sample of known absolute configuration. In addition 2- and 3-hexenoic acid and some aromatic compounds were also found in varying quantities in both males and females along with hydrocarbons and fatty acids, although no species-specific profiles emerged.

An unexpected selectivity of a propranolol-derived molecular imprint for tamoxifen

During the evaluation of molecular imprinted polymers (MIPs) prepared against the drug tamoxifen a propranolol-derived MIP was used as a positive control. Surprisingly the propranolol-derived MIP showed considerable selectivity towards tamoxifen, and was indeed much more selective than the MIP prepared using tamoxifen as the imprint molecule. The consequences of this unexpected, cross reactivity for the use of MIPs in analytical chemistry is discussed.

Defensive role of secretion of ectal mandibular glands of the wasp Polistes dominulus

Ectal mandibular glands of insects are exocrine glands localized in the anterior-lateral region of the head, close to the base of the mandibles. In social wasps, the gland is composed of secretory cells and a reservoir into which the secretion accumulates. At the time of emission the secretion flows onto a specialized cuticular area on the outside of the base of the mandibles. Secretion of Polistes dominulus is emitted only when wasps are greatly disturbed or in the presence of predators, and its function seems to be mainly defensive. Morphometric studies did not reveal any size differences between the glands of the queens and those of the workers. GC-MS analyses of the glands identified 32 compounds, mainly acids and aldehydes in the range C2-C18. The overall odor, caused by the mixture of aldehydes, is distinct. Workers do not respond strongly to the odor. The secretion probably serves as a warning signal to vertebrate predators.

Causes of Alzheimer's disease: paracetamol (acetaminophen) today? Amphetamines tomorrow?

Phenacetin was implicated as a causative factor in Alzheimer's disease (AD) in 1971. Although the chief metabolite, paracetamol, was earlier identified as responsible for its analgesic and antipyretic properties, a link with senile plaque formation does not appear to have been previously suspected. In common with paracetamol, so-called recreational drugs (RDs) likewise stimulate free radical activity, and might therefore pose a similar danger in terms of causing AD later in life. The case for regarding the brain as an even more delicate and vulnerable structure than currently believed, at risk especially from substances untested in man but of proven neurotoxicity in rodents and non-human primates, needs to be taken more seriously than at present.

Effects of infectious hematopoietic necrosis virus and infectious pancreatic necrosis virus infection on hematopoietic precursors of the zebrafish

The zebrafish Danio rerio is a new model system for studying the genetics of hematopoiesis. To define naturally occurring viruses which could infect and replicate within hematopoietic precursors of the zebrafish, infectious hematopoietic necrosis virus (IHNV) and infectious pancreatic necrosis virus (IPNV) were studied. Infection of whole fish with viral supernatants demonstrated infectious replicants for both viruses, indicating that the virus host range includes the zebrafish. In other species, infection with these viruses leads to prominent hematopoietic necrosis of the head kidney, the major site of adult hematopoiesis. We detected a transient toxicity of the virus to hematopoietic precursors and terminally differentiated red cells after viral infections. The kinetics of hematopoietic defects between IHNV and IPNV infection differed; fish infected with either virus, however, recovered by 6 days postinfection. In contrast to other fish infected with the virus, hematocrit did not change appreciably during this time. These studies are the first to demonstrate IHNV and IPNV infection of the zebrafish and reveal the potential for use of such viruses for gene transfer experiments to infect zebrafish hematopoietic cells.

Calcium confusion--is the variability in calcium response by Sertoli cells to specific hormones meaningful or simply redundant?

When results of more than ten different studies on hormone-induced calcium signals in Sertoli cells are taken together, a wide variety of responses emerges. The reported changes range from increased concentrations, via no response at all, to decreased calcium concentrations. Minor variations in cell isolation techniques, culture conditions, or techniques for measuring the intracellular calcium could explain some of these differences. However, erratic variations in response are also observed within research groups under very similar experimental conditions. Such 'negative' findings are mainly reported orally and do not further penetrate the scientific community. As hormone-dependent calcium responses evidently may depend very much on the context of the cells, calcium transients would appear to be unreliable bioassay principles with which to detect the primary actions of FSH and effectors such as androgens on Sertoli cells. A more important biological question is whether these sometimes opposed calcium transients are connected with a particular cellular response. To date there is no evidence for such a tight coupling in Sertoli cells, implying that, at least under in vitro conditions, calcium signals might even be redundant altogether. Such calcium variability is probably not unique to Sertoli cells, and the aim of this commentary is to promote an open debate that may help to transform the current state of 'calcium confusion' into a better understanding of the intracellular calcium language.

Rapid androgen actions on calcium signaling in rat sertoli cells and two human prostatic cell lines: similar biphasic responses between 1 picomolar and 100 nanomolar concentrations

Androgen-induced calcium fluxes and gap junctional intercellular communication (GJIC) were studied in three different cell types. A transient (2-3 min duration) increase in intracellular calcium levels was observed within 20-30 sec of androgen addition, which was followed by a plateau phase with steroid concentrations higher than 1 nM. The kinetics of the calcium responses were similar in immature rat Sertoli cells, which contain normal nuclear receptors; the human prostatic tumor cell line, LNCaP, which contains a mutated nuclear receptor; and the human prostatic cell line, PC3, which does not contain a nuclear receptor. The human A431 tumor cell line did not respond to androgens. Concentrations of testosterone and the synthetic androgen, R1881, between 1-1000 pM induced transient calcium increases with ED(50) values near 1 pM and 1 nM, whereas dihydrotestosterone (DHT) was not active at these concentrations. At concentrations higher than 1 nM, testosterone, R1881, and DHT were equipotent in stimulating an increase in calcium that lasted for more than 10 min, with ED(50) values between 5 and 20 nM. Testosterone covalently bound to albumin was also active, whereas 11 related androstane compounds as well as progesterone and estradiol-17beta were inactive at 1000 nM. The calcium response induced by the three androgens (10 nM) was abolished in all cell types by hydroxyflutamide (1000 nM) and finasteride (1000 nM), but not by cyproterone acetate (1000 nM). The calcium response was also abolished in the absence of extracellular calcium and strongly inhibited by the presence of verapamil. Exposure of the responsive cells to brief (150-sec) pulses of androgens generated calcium responses that were similar to those after continuous exposure. After exposure of Sertoli cells for only 30 sec to 100 nM testosterone, the calcium response lasted for at least 50 min. Although nuclear binding of androgens could be demonstrated, there was no evidence for tight binding to the plasma membrane under similar conditions. When protein synthesis was inhibited, an enhancement of GJIC between rat Sertoli cells, but not between LNCaP cells or PC3 cells, was observed within 15 min of the addition of 10 nM testosterone. Because nuclear androgens are not present in PC3 cells and many functional properties of the responsive system are different from the nuclear receptor in all three cell types, we postulate the existence of an alternative cell surface receptor system with biphasic response characteristics (high and low affinity). The calcium signals are probably coupled to the regulation of gap junctional efficiency between Sertoli cells. The low-affinity receptors may convey complementary androgen signals at elevated local levels such as in the testis, when nuclear receptors are (over)saturated.

Real-time studies of the interactions between epidermal growth factor and its receptor during endocytic trafficking

The interactions of growth factors with cell surface receptors regulate fundamental cell processes, such as growth, differentiation and transformation. Understanding the nature of these interactions at the molecular level is of fundamental importance in cell biology. This is not only from the point of view of basic science, but also because of the repercussions such knowledge might have in understanding the mode of action of drugs in cells. Receptor mediated endocytosis has been implicated in the downregulation of the mitogenic signal. However, no data are thus far available on how growth factor/receptor interactions might control endocytic trafficking. Here we show that information on modes of binding and receptor conformational changes can be obtained using time-resolved fluorescence methods. We have found that fluorescent probes bound to epidermal growth factor (EGF) show dynamic fluorescence quenching when EGF is bound to internalising EGF receptors (EGFR). We propose that this dynamic quenching takes place because EGF-bound probes interact with tryptophan residues in the extracellular domain of the EGF-EGFR complex. Real-time accumulation of fluorescent decays has also allowed us to follow the time course of a conformational change in EGFR occurring during endocytosis, and correlate this information with endosomal trafficking and EGFR recycling.

Optimisation of procedures for the extraction of structural analogues of propranolol with molecular imprinted polymers for sample preparation

A propranolol-derived molecular imprinted polymer (MIP) was prepared using methacrylic acid as monomer and ethylene glycol dimethacrylate as cross-linker. The extraction properties of five compounds structurally related to propranolol were assessed on the MIP and on a blank polymer made under the same conditions but in the absence of an imprint molecule. Using application from aqueous solution with methanol-water-triethylamine (TEA)-based solvents for elution (i.e. reversed-phase conditions) the MIP showed only marginal selectivity for the compounds on the MIP compared to the blank. Despite the limited selectivity there did appear to be a relationship between structure of the compound (relative to propranolol) and the extent of selective retention. Application of the compounds in toluene with elution using toluene-TEA or toluene-trifluoroacetic acid resulted in the MIP showing dramatically enhanced retention and selectivity of the compounds on the MIP compared to the blank. The enhanced selectivity for extraction on to the MIP relative to the blank, for all compounds using normal-phase solvents seem to be a class effect as there was no apparent relationship between compound structure and retention.

Synchrotron X-ray investigations into the lamellar gel phase formed in pharmaceutical creams prepared with cetrimide and fatty alcohols

Semisolid liquid paraffin-in-water emulsions (aqueous creams) prepared from cetrimide/fatty alcohol mixed emulsifiers, and ternary systems formed by dispersing the mixed emulsifier in controlled percentages of water were examined as they aged using a combination of low and high angle X-ray diffraction measurements (Daresbury Laboratory Synchrotron Radiation Source). The results were correlated with the rheological properties measured in earlier studies. The cationic emulsifying wax showed phenomenal swelling in water. The reflection that incorporates interlamellar water increased continuously from 74 A at 28% water to over 500 A at 93% water. The trend was not influenced by the method of incorporation of the components and swollen lamellar phase was also identified in the corresponding emulsion. The swelling, which was due to electrostatic repulsion, was suppressed by salt and was reduced when the surfactant counterion was changed from Br(-) to Cl(-). Changes in rheological properties on storage and in the presence of salt were correlated with changes in water layer thickness. High angle diffraction confirmed that the hydrocarbon bilayers were in the hexagonal alpha-crystalline mode of packing. Ternary systems and creams prepared from pure alcohols, although initially semisolid, were rheologically unstable and broke down. Low angle X-ray study into the kinetics of structure breakdown showed that the swollen lamellar gel phase formed initially swells even further on storage before separating.

Use of Dufour's gland secretion in nest defence and brood nutrition by hover wasps (Hymenoptera, Stenogastrinae)

Social wasps of the subfamily Stenogastrinae produce an abdominal secretion that is used in two distinct biological contexts. First, the secretion plays an important role in larval nutrition where it serves as a substrate in which food is placed by the adults for eventual consumption by the larvae. Second, in several species, females apply the same secretion to the substrate on which their nests are constructed, where it constitutes a sticky barrier that defends the immature brood from predation by ants. This paper describes for the first time ant guard construction behaviour of three species of stenogastrine wasps belonging to the genera Eustenogaster and Liostenogaster. The identification of compounds making up these secretions was also performed by gas chromatography-mass spectrometry. Ant guards and brood secretions were similar, with saturated and unsaturated long chain hydrocarbons and alcohols as major components. We further confirm that the glandular source of abdominal secretion is the Dufour's gland. This gland contains the same hydrocarbons, and in the same proportions as ant guards and brood secretion. We discuss the fundamental importance of Dufour's gland secretion in the social life of these wasps by comparing species with and without ant guards within the subfamily.

Justification of pulse oximeter costs for paramedic prehospital providers

OBJECTIVE

To assess the potential cost savings of decreasing prehospital oxygen utilization by using pulse oximetry to identify those patients who do not require supplemental oxygen.

METHODS

A prospective, controlled trial was performed comparing rates of oxygen utilization by paramedics with and without access to pulse oximetry. Consecutive patient encounters over a ten-week period were randomized by day of presentation. Pulse oximeters were made available on alternate days. On those days, patients whose oxygen saturations were less than 95% were treated with supplemental oxygen.

RESULTS

The use of pulse oximeters incurred a saving of 0.14 "D"-size oxygen cylinders per call. For the authors' service, this translates to a potential saving of $2,324 (C)/vehicle/year.

CONCLUSION

For regions with patient demographics similar to the authors', the initial cost of providing paramedics with pulse oximeters may be offset by savings in oxygen consumption. A formula is provided to allow individual ambulance services to calculate the potential savings for their service.

Lack of immunity in university students before an outbreak of serogroup C meningococcal infection

Immunity to meningococci was determined in infected and uninfected students before and during an outbreak of serogroup C meningococcal infection at a university in the United Kingdom. No immunity against the outbreak strain was detected in serum taken from infected students prior to the outbreak or at the time of admission; bactericidal activity developed during convalescence. Carriage of all strains of serogroup C meningococci in asymptomatic students was low (0.9%), and no carriage of the outbreak strain could be detected. Immunity in the at-risk student population before the outbreak was low: 90% of students had no significant bactericidal activity against the outbreak strain. A low prevalence of carriage of the outbreak strain, together with a low prevalence of protective immunity within the student population, was associated with a high incidence of invasive disease in those who acquired the outbreak strain.

Selective pressure as an essential force in molecular evolution of myeloid leukemic clones: a view from the window of Fanconi anemia

Specific chromosomal deletions are commonly found in bone marrow cells of children with Fanconi anemia (FA) whose disease has evolved to myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Identical deletions are found in adults with MDS/AML with a history of exposure to alkylating agents (secondary MDS/AML). While deleted chromosomal regions likely harbor genes encoding proteins with tumor suppressor (TS) function, such genes have not been identified and the environmental forces by which these mutant clones are selected remain unclear. A consistent signaling abnormality in cells bearing mutations of the Fanconi anemia complementation group C (FA-C) gene (FANCC) has revealed a potential selective force. Hematopoietic progenitor cells from patients and mice with FANCC mutations are hypersensitive to the inhibitory effects of IFNgamma and TNFalpha. Consequently, clonal outgrowths in FA likely result from strong selective pressure for stem and/or progenitor cells resistant to these inhibitory cytokines. Additional mutations that inactivate signaling pathways for these inhibitors would create a cell with a profound proliferative advantage over its apoptosis-prone counterparts. Here, we present preliminary evidence supporting a selection-based model of leukemic evolution and argue that MDS in FA patients is a de facto model of secondary MDS in non-FA adults.

Extended circular dichroism measurements using synchrotron radiation show that the assembly of clathrin coats requires no change in secondary structure

A number of models have been proposed for the assembly of clathrin triskelia into coats. However, little is known of the effects of assembly on triskelion structure. A more detailed knowledge of the way in which assembly affects triskelion structure would be valuable for assessing the relative merits of the proposed models. The development of a vacuum-ultraviolet circular dichroism (CD) instrument that uses synchrotron radiation as a light source has allowed us to extend the range of CD measurements to shorter wavelengths. This has greatly increased signal quality even for highly scattering samples. Also, we have improved CD data analysis to provide standard deviations for calculated secondary structure content. These developments have increased the precision of CD analysis beyond what has been thus far possible. Using these developments, we have determined the secondary structure content of all components of coat protein, under both assembly and dissociating conditions. The assembly of coats does not incur any change in secondary structure content, but a 10% loss of triskelion helical content accompanies assembly in the absence of AP-2. We conclude that coat assembly requires no detectable reorganization of triskelion structure. Our result indicates that AP-2 stabilizes helical structure in the triskelion, and we propose that this increases triskelion rigidity, restricting the range of coat sizes.

The alpha-helix folds on the millisecond time scale

It has long been believed that nucleation of the alpha-helix is a very fast reaction, occurring in around 10(-7) s. We show here that helix nucleation, in fact, takes place on the millisecond time scale. The rate of alpha-helix nucleation in two polyalanine-based peptides and in lysine and glutamic acid homopolymers was measured directly by stopped-flow deep UV CD with synchrotron radiation as the light source. Synchrotron radiation CD gives far superior signal to noise than a conventional instrument. The 16-aa AK peptide folds with first-order kinetics and a rate constant of 15 s-1 at 0 degrees C. The rate-determining step is presumably the initiation of a new helix, which occurs at least 10(5) times slower than expected. Helix folding occurs in at least two steps on the millisecond time scale for the longer peptides, with a transient overshoot of helix content significantly greater than at equilibrium, similar to that seen in the folding of several proteins. We suggest that the overshoot is caused by the formation of a single long helix followed by its breakage into the two or more helices present at equilibrium.

Iron in the basal ganglia in Parkinson's disease. An in vitro study using extended X-ray absorption fine structure and cryo-electron microscopy

Iron is found in high concentration in some areas of the brain, and increased iron in the substantia nigra is a feature of Parkinson's disease. The purpose of this study was to investigate the physical environment of brain iron in post-mortem tissue to provide information on the possible role of iron in neurodegeneration in Parkinson's disease. Iron has also been implicated as the cause of signal loss in areas of high brain iron on T2-weighted MRI sequences. Knowledge of the physical environment of the brain iron is essential in interpreting the cause of signal change. Post-mortem tissue was obtained from six cases of Parkinson's disease and from six age-matched controls. Iron levels were measured using absorption spectrophotometry. Extended X-ray absorption fine structure was used to evaluate the atomic environment of iron within the substantia nigra and both segments of the globus pallidus. Cryo-electron transmission microscopy was used to probe the iron storage proteins in these areas. Iron levels were increased in the parkinsonian nigra and lateral portion of the globus pallidus. Spectra from the extended X-ray absorption fine structure experiments showed that ferritin was the only storage protein detectable in both control and parkinsonian tissue in all areas studied. Cryo-electron transmission microscopy studies showed that ferritin was more heavily loaded with iron in Parkinson's disease when compared with age-matched controls. In summary we have shown that iron levels are increased in two areas of the brain in Parkinson's disease including the substantia nigra, the site of maximal neurodegeneration. This produces increased loading of ferritin, which is the normal brain iron storage protein. It is possible that increased loading of ferritin may increase the risk of free radical-induced damage. Differences in ferritin loading may explain regional differences in iron's effect on the T2 signal.

A practical guide to evaluation and treatment of infections in patients with central venous catheters

Infection in patients with central venous catheters can be a serious complication leading to costly disruption of their ongoing medical needs. A systematic, algorithm-based approach to evaluation and treatment of infections in this very diverse population is presented and emphasizes rapid and thorough determination of infection sources and outlines decisions regarding use of antibiotic therapy. Catheter-related infections, including bacteremia and exit site, tunnel, and pocket infections, can be treated in many cases without removal of the device. Recently developed treatment protocols and new technologies devised to decrease infection risk and improve outcome are discussed.

Dynamics of carriage of Neisseria meningitidis in a group of military recruits: subtype stability and specificity of the immune response following colonization

Meningococcal carriage and the immune response to colonization were studied in a group of military recruits undergoing basic training. Subtyping by determination of the class 1 protein sequence clearly differentiated between strains and demonstrated the dynamics of carriage and transmission. Expression of class 1 protein by each strain remained stable during prolonged carriage by different subjects. Following colonization, a marked increase in serum bactericidal response occurred, which was specific for the subtype of the acquired strain and was associated with an increase in reactivity by Western blot to the homologous class 1 protein. Subjects colonized by multiple strains showed evidence of a specific immune response to the class 1 protein of each strain acquired. The subtype specificity of the bactericidal response to meningococci and the stability of expression of the class 1 protein have important implications for the design of vaccines for prevention of serogroup B meningococcal disease.

The Ontario Prehospital Advanced Life Support (OPALS) Study: rationale and methodology for cardiac arrest patients

The Ontario Prehospital Advanced Life Support Study represents the largest prehospital study yet conducted, worldwide. This study will involve more than 25,000 cardiac arrest, trauma, and critically ill patients over an 8-year period. The study will evaluate the incremental benefit of rapid defibrillation and prehospital Advanced Cardiac Life Support measures for cardiac arrest survival and the benefit of Advanced Life Support for patients with traumatic injuries and other critically ill prehospital patients. This article describes the OPALS study with regard to the rationale and methodology for cardiac arrest patients.