A preliminary analysis of the variation in circulating 25-hydroxycholecalciferol concentrations in peri-partum spring-calving dairy cows

Vitamin D has a well-established role in regulating the intestinal absorption of minerals but its association with immunity has not been extensively explored in livestock. Although an optimal circulating concentration of 30 ng/ml 25-hydroxycholecalciferol (25(OH)D) is proposed for immune function, it is unknown if this vitamin D concentration is sufficient, particularly for cows under a pasture-based, spring-calving dairy production system. The objectives of this retrospective analysis were to assess circulating vitamin D concentrations in a total of 843 bio-banked serum samples from Holstein-Friesian dairy cows enrolled from 12 spring-calving, pasture-based dairy farms in Ireland. Mean 25(OH)D concentrations were 36.3 ng/ml at calving, 30.7 ng/ml at 7 days post-partum (DPP), and 38.3 ng/ml at 21 DPP. However, mean concentrations masked significant inter-farm and inter-individual variation (P < 0.05). In fact, the proportion of cows with vitamin D insufficiency of < 30 ng/ml was found to be 33.8%, 55.5% and 19.5% at each time point, respectively. In addition, 25(OH)D concentrations correlated positively with immune cell populations (monocytes and lymphocytes) and negatively with blood urea and non-esterified fatty acids (NEFA) at 7 DPP. This is the first report of 25(OH)D concentrations in pasture-based peripartum dairy cows and we show a high degree of variation across farms and between individual animals. Sub-optimal concentrations of vitamin D in some post-partum cows may predispose cattle to multiple metabolic or infectious diseases, and therefore further work is now warranted.

Use of a cow-side oestrus detection test for fertility management in Kenyan smallholder dairy herds

Background: The use of artificial insemination (AI) has great potential to improve smallholder dairy herds in Africa, however poor success and, in some situations, high costs in Kenya, have been discouraging.  Effective AI requires accurate oestrus detection and the measurement of progesterone (P4) can be used to indicate oestrus as well as non-pregnancy.  A cow-side progesterone lateral flow test, P4 Rapid, was evaluated as an aid to detect oestrus and non-pregnancy in Kenyan dairy cows, and assessed for association with AI efficiency. 

Methods: A total of 527 cows were enrolled in the study, from two counties in central and southern Kenya.  Cattle in the test group (n = 308) were presented when suspected to be in oestrus and tested with the P4 Rapid (low P4 = oestrus, medium P4 = inconclusive, high P4 = not in oestrus/pregnant).  Cattle with low P4 were inseminated.  Cattle in the control group (n = 219) were inseminated when oestrus behaviour was detected i.e. standard practice.

Results: Of the total P4 Rapid tests performed (n = 745), 1.5% were inconclusive, with the true accuracy of the test between 87-97%.  Conception rates were not significantly higher in the test group (83.9%) compared to the control group (77.9%). Abortion rates were not significantly different between the control (9.5%) and test groups (8.2%).  In the test group, 6.2% (19/308) cows showed a medium or high P4 level on day 0 and nine of these were subsequently found to have been already pregnant.

Conclusions: The data indicated that the P4 Rapid test can be a useful tool to assist farmer decision-making in the confirmation of correct timing for AI, and importantly may avoid unnecessary inseminations in pregnant animals, thus reducing the risk of AI-induced abortion.

Use of a cow-side oestrus detection test for fertility management in Kenyan smallholder dairy herds

Background: The use of artificial insemination (AI) has great potential to improve smallholder dairy herds in Africa, however high costs and often poor success rates have been discouraging.  Effective AI requires accurate oestrus detection and the measurement of progesterone (P4) can be used to indicate oestrus as well as non-pregnancy.  A cow-side progesterone lateral flow test, P4 Rapid, was evaluated as an aid to detect oestrus and non-pregnancy in Kenyan dairy cows, and assessed for association with AI efficiency.  Methods: A total of 527 cows were enrolled in the study, from two counties in central and southern Kenya.  Cattle in the test group (n = 308) were presented when suspected to be in oestrus and tested with the P4 Rapid (low P4 = oestrus, medium P4 = inconclusive, high P4 = not in oestrus/pregnant).  Cattle with low P4 were inseminated.  Cattle in the control group (n = 219) were inseminated when oestrus behaviour was detected i.e. standard practice. Results: Of the total P4 Rapid tests performed (n = 745), 1.5% were inconclusive, with the true accuracy of the test between 87-97%.  Conception rates were not significantly higher in the test group (83.9%) compared to the control group (77.9%). Abortion rates were not significantly different between the control (9.5%) and test groups (8.2%).  In the test group, 6.2% (19/308) cows showed a medium or high P4 level on day 0 and 9 of these were subsequently found to have been already pregnant. Conclusions: The data indicated that the P4 Rapid test can be a useful tool to assist farmer decision-making in the confirmation of correct timing for AI, and importantly may avoid unnecessary inseminations in pregnant animals, thus reducing the risk of AI-induced abortion.

Evaluation of procalcitonin as a contribution to antimicrobial stewardship in SARS-CoV-2 infection: a retrospective cohort study

It can be a diagnostic challenge to identify patients with coronavirus disease 2019 in whom antibiotics can be safely withheld. This study evaluated the effectiveness of a guideline implemented at Sheffield Teaching Hospitals NHS Foundation Trust that recommends withholding antibiotics in patients with low serum procalcitonin (PCT), defined as ≤0.25 ng/mL. Results showed reduced antibiotic consumption in patients with PCT ≤0.25 ng/mL with no increase in mortality, alongside a reduction in subsequent carbapenem prescriptions during admission. The results support the effectiveness of this guideline, and further research is recommended to identify the optimal cut-off value for PCT in this setting.

Purulent vaginal discharge diagnosed in pasture-based Holstein-Friesian cows at 21 days postpartum is influenced by previous lactation milk yield and results in diminished fertility

In a subset of dairy cows, prolonged pathological uterine inflammation results in purulent vaginal discharge (PVD), which can have negative consequences for both fertility and milk production. However, unlike for intensive systems, analysis of the effects of PVD in predominantly pasture-based herds is limited. The objective of this study was to assess the effect of PVD in spring-calving, pasture-based dairy cows on production and reproduction indices, stratified according to previous full-lactation milk yield. We assessed clinical disease as defined by vaginal mucus score (VMS) in 440 Holstein-Friesian cows from 5 farms. Cows were categorized as healthy (VMS 0) or having PVD (VMS 1-3) at 21 d postpartum. We recorded 305-d milk, milk protein, and milk fat yields (kg) before and after disease diagnosis, as well as fertility data, such as services per conception and the calving-conception period (CCP). Using SAS 9.4 (SAS Institute Inc., Cary, NC), we analyzed data using PROC MIXED, PROC PHREG, and PROC LOGISTIC to determine the least squares means differences and hazard and odds ratios between the groups, respectively. Overall, a 60% prevalence of PVD was recorded at 21 d postpartum. Milk yield and milk constituents were similar between all VMS categories and between healthy cows and cows with PVD. Although cows in the 4 VMS categories had statistically similar CCP, cows with PVD had a significantly longer CCP than healthy cows on average (9 d). The hazard ratio for cows with PVD was 0.66, indicating a 34% higher risk of a prolonged CCP than healthy cows. Odds ratio analysis determined that cows with PVD were 3 times more likely not to conceive at all, twice as likely not to conceive at first service, twice as likely not to conceive by 100 d postpartum, and 3 times more likely to fail to conceive before 150 d postpartum compared with healthy cows. Cows were retrospectively categorized as having low or high milk yield, based on whether they were above or below the median 305-d milk yield of the study population (6,571 kg) in the lactation before vaginal mucus scoring. Based on a univariate odds ratio, high-yield cows were 1.6 times more likely to present with PVD in the subsequent lactation. The number of services per conception did not differ between healthy and PVD cows in the low- and high-yield groups. In the high-yield group, cows with PVD were 4.9 times more likely not to conceive, 2.7 times more likely to require multiple services to conceive, 2.1 times more likely to remain not pregnant by 100 d postpartum, and 4.4 times more likely to remain not pregnant by 150 d postpartum. The CCP was also significantly longer in cows with PVD than their healthy counterparts (115.9 ± 4.9 and 104 ± 7.4 d, respectively). In conclusion, PVD significantly increased the CCP in all cows, but to a greater extent in cows with a high milk yield in the lactation before disease diagnosis.

Social interactions do not drive territory aggregation in a grassland songbird

Understanding the drivers of animal distributions is a fundamental goal of ecology and informs habitat management. The costs and benefits of colonial aggregations in animals are well established, but the factors leading to aggregation in territorial animals remain unclear. Territorial animals might aggregate to facilitate social behavior such as (1) group defense from predators and/or parasites, (2) cooperative care of offspring, (3) extra-pair mating, and/or (4) mitigating costs of extra-pair mating through kin selection. Using experimental and observational methods, we tested predictions of all four hypotheses in a tallgrass prairie in northeast Kansas, United States. Grasshopper Sparrow (Ammodramus savannarum) males formed clumps of territories in some parts of the site while leaving other apparently suitable areas unoccupied. Despite substantial sampling effort (653 territories and 223 nests), we found no support for any hypothesized social driver of aggregation, nor evidence that aggregation increases nest success. Our results run counter to previous evidence that conspecific interactions shape territory distributions. These results suggest one of the following alternatives: (1) the benefits of aggregation accrue to different life-history stages, or (2) the benefits of territory aggregation may be too small to detect in short-term studies and/or the consequences of aggregation are sufficiently temporally and spatially variable that they do not always appear to be locally adaptive, perhaps exacerbated by changing landscape contexts and declining population sizes.

A review of troponin assay performance in Wales: can the same (method-dependent) decision limits be used in different sites?

An audit of troponin measurement protocols in use in Wales showed significant variations in practice with no consensus on analytical methods, or in the selection of a decision limit for the diagnosis of myocardial damage. Peer review data on assay imprecision at concentrations approaching the analytical limit of detection are lacking. The objective of the study was to establish clinically relevant precision profiles for the troponin methods used throughout Wales, which could be used to develop a standardized approach to the selection of a decision limit. A series of five pools of human serum spiked with troponin I-T complex were prepared and stored at -7°C until despatch. Five sets of each pool were dispatched to all Welsh laboratories and stored at -20°C until analysis. The analysis protocol consisted of two replicates of each pool per batch, and two batches per day for five days ( n=20). All the laboratories performed all the measurements in the same week. The lowest concentration providing a 10% coefficient of variation (CV) was 0.02 µg/L for the Roche method and 0.11 µg/L for the Beckman AccuTnI. The lowest concentrations that could be distinguishable from the 99th percentile reference limit were 0.02 µg/L for the Roche method and 0.07 µg/L for the Beckman AccuTnI. Current methods do not achieve the 10% CV at the 99th percentile reference limit proposed by the European Society of Cardiology. Use of the lowest concentration that can be reliably distinguished from the 99th percentile reference limit offers a novel alternative decision limit, which provides a slightly lower concentration than at the 10% CV but maintaining confidence in the assay that false-positive rates will be minimized.

Recommended standards for biochemical markers of myocardial damage: All Wales Clinical Biochemistry Audit Group

The effective use of cardiac-specific troponin estimations in the diagnosis of acute myocardial infarction (AMI) is clouded by the imprecise definition surrounding the decision limits. This has led to a wide variation of criteria for the diagnosis of myocardial infarction. A survey of troponin measurements in Welsh laboratories, undertaken in 2003 under the auspices of the All Wales Clinical Biochemistry Audit Group, revealed significant variations in laboratory and clinical practice. Extensive discussion and consultation led by a working group of clinical biochemists and cardiologists in Wales culminated in recommendations concerning the use of troponin assays to establish myocardial damage.

The key recommendations are:

•Cardiac troponin (T or I) should be the first-line test for myocardial damage;

•Two samples should be collected, at admission and 12-24 h later. The first sample is used for 'rule in' purposes, but not to 'rule out' myocardial damage;

•Only one threshold (cut-off) value for troponin should be quoted on laboratory reports, values above which are indicative of myocardial damage.

A study by the Wales External Quality Assurance Scheme (WEQAS) enabled the derivation of the recommended cut-off concentrations of troponin for defining myocardial damage, defined for each assay as the concentration that can be reliably distinguished, with a confidence interval of 99%, from the 99th percentile reference limit.

These recommended standards provide a rationale for a uniform approach for troponin assays for patients with chest pain, working towards a standardized approach to the diagnosis and management of patients presenting with acute coronary syndromes.

Clinically targeted screening for congenital CMV - potential for integration into the National Hearing Screening Programme

Screening for a condition should only be undertaken if certain strict criteria are met. Congenital CMV (cCMV) is a leading cause of sensorineuronal hearing loss (SNHL) and meets many of these criteria, but is not currently screened for in the UK. Ganciclovir reduces CMV-induced progressive SNHL if treatment is begun in the first month of life. The Newborn Hearing Screening Programme (NHSP) has been shown to identify SNHL at the earliest possible age. The potential of integrating screening for cCMV into the NHSP is discussed to consolidate the link between screening, early diagnosis and management.

CONCLUSION

The early diagnosis and treatment of cCMV may prevent a small proportion of late SNHL. In the absence of any screening programme, we provide evidence that clinically targeted screening through the NHSP is a potential option in the UK, enhancing the diagnostic pathway and enabling appropriate early treatment to reduce long-term morbidity.

Clinical language fMRI with real-time monitoring in temporal lobe epilepsy: online processing methods

The increasing demand for clinical fMRI data has resulted in a need to translate research methods to clinical use. Referrals for language lateralization prior to epilepsy surgery are becoming more common, but time constraints make this unachievable in many busy neuroimaging departments. This study examines whether a single covert verbal fluency paradigm with real-time monitoring and online processing (BrainWave) could replace conventional offline processing (SPM) for the purpose of establishing expressive language dominance prior to epilepsy surgery. We analyzed language fMRI results of 30 patients (17 female; 24 right-handed; median age: 30.5) with temporal lobe epilepsy. Concordance between visual assessment of SPM and BrainWave was 92.8%. Lateralization indices correlated closely with visual assessments of lateralization with a concordance of 85.7%. BrainWave provided a real-time, fast and accurate display of language lateralization easily applied in a clinical setting using only online image processing.

What predicts failed cannulation and therapy at ERCP? Results of a large-scale multicenter analysis

STUDY BACKGROUND AND AIMS: Predicting outcome at endoscopic retrograde cholangiopancreatography (ERCP) remains difficult. Our aim was to identify the risk factors for failed ERCP.

PATIENTS AND METHODS

A prospective multicenter study of ERCP was performed in 66 hospitals across England. Data on 4561 patients were collected using a structured questionnaire completed at the time of ERCP.

RESULTS

In total 3209 patients had not had an ERCP prior to the study period. Considering their first ever ERCP, 2683 (84 %) were successfully cannulated, 2241(70 %) had all intended therapy completed, 360 (11 %) had some intended therapy completed, and 608 (19 %) were considered to have had a failed procedure. For first ever ERCP, factors associated with incomplete procedure (odds ratio and 95 % confidence interval) were: Billroth surgery (9.2, 3.2 - 26.7), precutting (2.0, 1.6 - 2.7), common bile duct (CBD) stone size and number (3.2, 2.1 - 4.8 for multiple, large stones), interventions in the pancreatic duct (3.4, 1.6 - 7.0), and CBD stenting (2.8, 2.2 - 3.5). Analysis of the 1352 patients who had undergone an ERCP prior to the study period indicated previous failed ERCP was also predictive of incomplete therapy (1.5, 1.1 - 2.1). The modified Schutz score correlated with ERCP completion, as did the Morriston score, even when modified to include only variables measurable before the procedure.

CONCLUSION

This study confirms that patient- and procedure-based variables are key predictors of technical success and validates current methods of rating ERCP difficulty. Of note, a correlation between outcome and institutional factors, such as unit and endoscopist caseload, was not demonstrated.

Triennial Lactation Symposium: Effects of stress on postpartum reproduction in dairy cows

The objective was to review the effects of production stressors on reproductive performance of dairy cows. It has been well documented that genetic selection for milk yield over the last 50 yr has been associated with reduced fertility. In addition to negative associations between yield and conception rate, there is also an association between milk production and expression of behavioral estrus. Stress caused by production diseases in high-yielding dairy cows also contributes to the problems of poor fertility. Lameness results in reduced intensity of estrus and can contribute to ovulation failure, which is largely due to reduced pre-ovulatory estradiol secretion and failure of the LH surge. Mastitis has been associated with prolonged intervals to dominant follicle selection, and in animals with uterine infection the dominant follicle grows slower and produces less estradiol. In a recent study, we identified that milk yield was associated with an increased incidence of uterine infection, which is known to contribute to reduced fertility and prolonged calving-to-conception intervals. The incidence of uterine disease was 73% in high-yielding, compared with 45% in low-yielding cows. As well as effects at the ovary, various models of stress have also been shown to perturb endocrine secretion in the hypothalamus and anterior pituitary. In conclusion, the adverse effects on fertility associated with genetic selection for yield in dairy cows is, in part, associated with increased incidences of production disease-induced stress but is also associated with high milk yield.

Evidence based management guidelines for the detection and treatment of congenital CMV

CMV is the most common congenital infection in newborns worldwide. Congenital CMV causes sensorineural hearing loss in a significant proportion of infected newborns, while the majority of newborns are asymptomatic. In the last three years there have been significant advances in the diagnosis and treatment of congenital CMV. We have developed practical evidence based guidelines for the management of congenital CMV.

Traditional herbal remedies that influence cell adhesion molecule activity

Many traditional medicines have demonstrated immune activity, however, research has largely neglected their effects on cell adhesion molecules (CAMs). This review reports on extracts from 37 medicinal plant species, similar to or replicating traditional preparations, that up- or downregulate either gene or protein activity of CAMs. The majority of the investigations were in vitro, primarily of the immunoglobulin superfamily of CAMs, specifically intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and secondarily on the integrin (CD11b or MAC-1) and selectin (E-selectin and P-selectin) families of CAMs. The following plant species have demonstrated modulation of multiple CAMs: Artemisia asiatica, Boswellia serrata, Canscora decussata, Cinnamomum povectum, Dehaasia incrassate, Ganoderma lucidum, Ginkgo biloba, Hypericum perforatum, Juglans regia, Lycopus lucidus, Panax notoginseng, Rheum undulatum, Salvia miltiorrhiza. Many other species have documented activity on one CAM. Currently there are limited in vivo/ex vivo investigations, including a clinical trial on Mahonia aquifolium. Although further evidence is needed, the data suggest that the reviewed botanical medicines may have the potential to provide therapeutic potential in disease processes involving CAMs. Additionally, the reported success of many of these plant extracts by traditional cultures and modern phytotherapists may involve the modulation of CAMs.

Monitoring clinical outcomes, pathological changes and shedding of Chlamydophila abortus following experimental challenge of periparturient ewes utilizing the natural route of infection

Enzootic abortion of ewes (EAE) caused by Chlamydophila abortus is an important disease resulting in significant lamb loss in most sheep producing countries. Ewes are considered to be naturally infected with C. abortus via the oral-nasal route and may become persistent carriers, shedding during subsequent oestrous cycles and at lambing. The aim of this study was to monitor the clinical outcomes, pathological changes and shedding of C. abortus in 18 periparturient orally infected sheep for two breeding seasons. In the first season, C. abortus was detected by real-time PCR (rt-PCR) in 13/18 conjunctival swabs at oestrus. Three out of the 15 pregnant ewes gave birth to 1 live and 1 dead lamb, and 2 of them aborted. Following parturition/abortion, C. abortus was detected in 12/15 vaginal swabs and in all the collected foetal membranes. However, only those membranes containing high copy numbers of the bacterium displayed the EAE typical lesions. In the second season, none of the 13 pregnant ewes aborted, and 5 of them gave birth to dead or weak lambs. C. abortus was not detected in conjunctival or vaginal swabs at oestrus or parturition. The bacterium was detected at low levels in 36% of the foetal membranes, but with no evidence of histopathological lesions. These results indicate that C. abortus can be detected in a large proportion of animals during the first pregnancy after oral infection. However, this proportion is reduced at the subsequent breeding season, confirming the occurrence of a chronic low level persistent infection in post-abortion/lambing ewes.

Plasma magnesium should be monitored perioperatively in patients undergoing colorectal resection

OBJECTIVE

Hypomagnesemia has been shown to have several clinically important sequelae. The aims of this study were: to assess the impact of bowel preparation, with sodium picosulphate (Picolax), on plasma electrolytes, with particular regard to plasma magnesium, in patients undergoing bowel preparation for colonoscopy and colorectal resection and to evaluate the influence of perioperative magnesium levels on postoperative cardiac dysrhythmias.

METHOD

Sixty-one patients receiving sodium picosulphate (Picolax) bowel preparation were studied in two groups: Colonoscopy (31 patients) and Colorectal resection (30 patients). Plasma sodium, potassium, magnesium, calcium, urea, creatinine and blood haematocrit were measured in all patients prior to commencement of bowel preparation, at the time of colonoscopy or colorectal resection and 24 h postoperatively (surgery group only). Mean electrolyte and haematocrit levels were then compared. Postoperative cardiac dysrhythmias were recorded and analysed.

RESULTS

No significant changes following bowel preparation were observed in plasma sodium, potassium, calcium or creatinine. Plasma urea fell following bowel preparation (colonoscopy P < 0.001, resection P = 0.004) and rose following resection (P = 0.002). Magnesium levels increased following bowel preparation in both groups (colonoscopy P < 0.001, resection P = 0.007) and fell following resection (P < 0.001). Thirty-four per cent (21/60 patients) were hypermagnesemic following bowel preparation and 20% (6/30 patients) became hypomagnesemic following surgery. Postoperative cardiac dysrhythmias were associated with lower magnesium levels at induction and postoperatively (P = 0.022 and P = 0.033).

CONCLUSION

Bowel preparation with Picolax does not appear to cause significant electrolyte disturbance, except in elevating plasma magnesium. Postcolorectal resection plasma magnesium dropped significantly suggesting perioperative monitoring and replacement should be routine following colorectal surgery.

Bacterial lipopolysaccharide induces an endocrine switch from prostaglandin F2alpha to prostaglandin E2 in bovine endometrium

Escherichia coli infection of the endometrium causes uterine disease after parturition and is associated with prolonged luteal phases of the ovarian cycle in cattle. Termination of the luteal phase is initiated by prostaglandin F(2alpha) (PGF) from oxytocin-stimulated endometrial epithelial cells. Compared with normal animals, the peripheral plasma of animals with E. coli infection of the endometrium had higher concentrations of lipopolysaccharide (LPS) and prostaglandin E(2) (PGE) but not PGF. Endometrial explants accumulated predominantly PGE in the culture medium in response to LPS, and this effect was not reversed by oxytocin. Endometrial cells expressed the Toll-like receptor 4/CD14/MD-2 receptor complex necessary to detect LPS. Epithelial and stromal cells treated with LPS had higher steady-state media concentrations of PGE rather than PGF. Arachadonic acid is liberated from cell membranes by phospholipase 2 (PLA2) enzymes and converted to prostaglandins by synthase enzymes. Treatment of epithelial and stromal cells with LPS did not change the levels of PGE or PGF synthase enzymes. However, LPS stimulated increased levels of PLA2 group VI but not PLA2 group IV C immunoreactive protein in epithelial cells. Endometrial cells expressed the E prostanoid 2 and E prostanoid 4 receptors necessary to respond to PGE, which regulates inflammation as well as being luteotropic. In conclusion, LPS detection by endometrial cells stimulated the accumulation of PGE rather than PGF, providing a mechanism to explain prolonged luteal phases in animals with uterine disease, and this PGE may also be important for regulating inflammatory responses in the endometrium.

The effect of Escherichia coli lipopolysaccharide and tumour necrosis factor alpha on ovarian function

PROBLEM

Pelvic inflammatory disease and metritis are important causes of infertility in humans and domestic animals. Uterine infection with Escherichia coli in cattle is associated with reduced ovarian follicle growth and decreased estradiol secretion. We hypothesized that this effect could be mediated by the bacterial lipopolysaccharide (LPS) or cytokines such as tumour necrosis factor alpha (TNFalpha).

METHOD OF STUDY

In vitro, bovine ovarian theca and granulosa cells were treated with LPS or TNFalpha and steroid secretion measured. In vivo, the effect of LPS or TNFalpha intrauterine infusion was determined by ovarian ultrasonography and measurement of hormones in cattle.

RESULTS

Lipopolysaccharide reduced granulosa cell estradiol secretion, whilst TNFalpha decreased theca and granulosa cell androstenedione and estradiol production, respectively. In vivo, fewer animals ovulated following intrauterine infusion with LPS or TNFalpha.

CONCLUSION

Lipopolysaccharide and TNFalpha suppress ovarian cell function, supporting the concept that pelvic inflammatory disease and metritis are detrimental for bovine ovarian health.

Guidelines on the management of common bile duct stones (CBDS)

The last 30 years have seen major developments in the management of gallstone-related disease, which in the United States alone costs over 6 billion dollars per annum to treat. Endoscopic retrograde cholangiopancreatography (ERCP) has become a widely available and routine procedure, whilst open cholecystectomy has largely been replaced by a laparoscopic approach, which may or may not include laparoscopic exploration of the common bile duct (LCBDE). In addition, new imaging techniques such as magnetic resonance cholangiography (MR) and endoscopic ultrasound (EUS) offer the opportunity to accurately visualise the biliary system without instrumentation of the ducts. As a consequence clinicians are now faced with a number of potentially valid options for managing patients with suspected CBDS. It is with this in mind that the following guidelines have been written.

Uterine diseases in cattle after parturition

Bacterial contamination of the uterine lumen is common in cattle after parturition, often leading to infection and uterine disease. Clinical disease can be diagnosed and scored by examination of the vaginal mucus, which reflects the presence of pathogenic bacteria such as Escherichia coli and Arcanobacterium pyogenes. Viruses may also cause uterine disease and bovine herpesvirus 4 (BoHV-4) is tropic for endometrial cells, causing a rapid cytopathic effect. The elimination of pathogens by the innate immune system is dependent on pattern recognition receptors binding pathogen-associated molecules. Uterine epithelial and stromal cells express receptors such as Toll-like Receptor 4 that binds E. coli lipopolysaccharide. The infertility associated with uterine disease is caused by damage to the endometrium and disruption of ovarian cyclic activity. Bacteria modulate endometrial prostaglandin secretion, and perturb ovarian follicle growth and function. Understanding the molecular basis of uterine disease will lead to novel approaches to treating infertility.

Ovarian follicular cells have innate immune capabilities that modulate their endocrine function

Oestrogens are pivotal in ovarian follicular growth, development and function, with fundamental roles in steroidogenesis, nurturing the oocyte and ovulation. Infections with bacteria such as Escherichia coli cause infertility in mammals at least in part by perturbing ovarian follicle function, characterised by suppression of oestradiol production. Ovarian follicle granulosa cells produce oestradiol by aromatisation of androstenedione from the theca cells, under the regulation of gonadotrophins such as FSH. Many of the effects of E. coli are mediated by its surface molecule lipopolysaccharide (LPS) binding to the Toll-like receptor-4 (TLR4), CD14, MD-2 receptor complex on immune cells, but immune cells are not present inside ovarian follicles. The present study tested the hypothesis that granulosa cells express the TLR4 complex and LPS directly perturbs their secretion of oestradiol. Granulosa cells from recruited or dominant follicles are exposed to LPS in vivo and when they were cultured in the absence of immune cell contamination in vitro they produced less oestradiol when challenged with LPS, although theca cell androstenedione production was unchanged. The suppression of oestradiol production by LPS was associated with down-regulation of transcripts for aromatase in granulosa cells, and did not affect cell survival. Furthermore, these cells expressed TLR4, CD14 and MD-2 transcripts throughout the key stages of follicle growth and development. It appears that granulosa cells have an immune capability to detect bacterial infection, which perturbs follicle steroidogenesis, and this is a likely mechanism by which ovarian follicle growth and function is perturbed during bacterial infection.

Risk factors for complication following ERCP; results of a large-scale, prospective multicenter study

BACKGROUND AND STUDY AIMS

Analyses of endoscopic retrograde cholangiopancreatography (ERCP) complication are often constrained by the number of endpoints observed. This large-scale study aimed to identify the principal risk factors for ERCP complication.

PATIENTS AND METHODS

This was a prospective multicenter study of ERCP complications, based in five English regions. An exploratory univariable analysis of patients' first recorded procedures identified potentially important patient- and procedure-related factors. For overall complications and pancreatitis, variables significant in univariable analysis were included in multiple regression.

RESULTS

A total of 66 centers collected data on 5264 ERCPs, performed on 4561 patients. A therapeutic intervention was attempted in 3447/4561 (76%) of patients as part of their first recorded ERCP. Following first recorded ERCP, 230 patients (5.0%) suffered > or = 1 complication: pancreatitis in 74 (1.6%), cholangitis in 48 (1.0 %), hemorrhage in 40 (0.9%), perforation in 20 (0.4%), and miscellaneous in 54 (1.2%). Significant factors from multiple regression were included in a multi-level analysis, which incorporated variables measured at the level of the endoscopist and hospital. For overall complication, risk factors ( P value, odds ratio [OR], 95% confidence interval [CI]) were: cannulation attempts > 1 ( P = 0.094, OR 1.32, 95% CI 0.95-1.83), precut ( P = 0.033, OR 1.55, 95 % CI 1.04-2.32), and suspected sphincter of Oddi dysfunction ( P = 0.121, OR 1.97, 95 % CI 0.84-4.64). For pancreatitis, risk factors ( Pvalue, OR, and 95 % CI) were: cannulation attempts > 1 ( P = 0.0001, OR 3.14, 95% CI 1.74-5.67), female sex ( P < 0.001, OR 2.22, 95% CI 1.43-3.45), age ( P < 0.002, OR 1.09 per 5 year decrease, 95% CI 1.03-1.15), and performance in a district (as opposed to university) hospital ( P = 0.034, OR 2.41, 95% CI 1.08-5.41).

CONCLUSION

Careful patient selection combined with skilled cannulation minimizes complications. Higher-risk procedures should be performed in specialist centers.

The relationship between uterine pathogen growth density and ovarian function in the postpartum dairy cow

In cattle, the first postpartum dominant follicle grows slower and produces less oestradiol in animals with high numbers of bacteria contaminating the uterine lumen. However, only bacteria that are uterine pathogens are correlated with severe clinical disease and an increased inflammatory response. It is unknown whether the effect on the ovary in relation to uterine bacterial contamination is associated with the presence of recognised uterine pathogens. Therefore, the present study examined the relationship between pathogenic bacteria in the postpartum uterine lumen, follicle growth and function and the formation of a competent corpus luteum. In addition, peripheral plasma concentrations of immune mediators were quantified. Swabs were collected from the uterine lumen of cattle on day 7 postpartum. Bacteria were cultured and identified and bacterial growth was scored semi-quantitatively. Animals were categorized into high or low recognized uterine pathogen contamination groups based on the number of colonies. Ovarian structures were monitored by daily transrectal ultrasonography and blood samples were collected. In animals with high numbers of uterine pathogens on day 7 postpartum, the diameter of the first postpartum dominant follicle was smaller and plasma oestradiol concentrations were lower. In addition, these animals had smaller corpora lutea, which produced less progesterone. Furthermore, animals with a high day 7 uterine pathogen growth density had higher peripheral concentrations of acute phase proteins. Thus, contamination of the uterus with recognized uterine pathogens is associated with ovarian dysfunction during the postpartum period. Furthermore, infection results in an increase in the production of inflammatory mediators.

Comparison of ultraviolet absorbance, chemiluminescence, and DOAS instruments for ambient ozone monitoring

This paper evaluates the accuracy of ozone measurements made by monitors that determine ozone concentrations in ambient air by UV absorption. These monitors are typically used to measure ozone for the purpose of establishing local compliance to air-quality standards. The study was predicated by the concern that commercially available UV absorbance O3 monitors may be subject to interference from volatile organic carbon (VOC) species that absorb light at 254 nm. To test for these and other effects, we compared simultaneous O3 measurements made by a commercial UV O3 monitor with an O3-NO chemiluminescence instrument, which is not subject to interference by VOC compounds. The comparisons were carried out in the summers of 1999 and 2000 at urban/industrial sites in Nashville and Houston, and in 2004 aboard a ship in the Gulf of Maine. In the two urban areas, we also compared the 03 measurements from these two methods with O3 measurements made by a long-path differential optical absorption spectrometer (DOAS). Our tests indicate that, with well-maintained monitors, there are no significant interferences even in areas with significant ambient concentrations of potentially interfering VOCs.

Expression and function of Toll-like receptor 4 in the endometrial cells of the uterus

Prostaglandins have a central role in many endocrine functions in mammals, including regulation of the life span of the corpus luteum by prostaglandin F(2alpha) (PGF) and prostaglandin E2 (PGE), which are secreted by the uterine endometrium. However, the uterus is readily infected with bacteria such as Escherichia coli, which disrupt luteolysis. Immune cells detect E. coli by Toll-like receptor 4 (TLR4) binding its pathogenic ligand, lipopolysaccharide (LPS), although signaling requires accessory molecules such as CD14. The objective of this study was to determine the effect of E. coli or LPS on the function of bovine endometrial cells, and whether purified populations of epithelial and stromal cells express the molecules involved in LPS recognition. In addition, because the female sex hormones estradiol and progesterone modify the risk of uterine infection, their effect on the LPS response was investigated. Endometrial explants produced prostaglandins in response to LPS, with an increased ratio of PGE to PGF. Addition of LPS or E. coli to stromal and epithelial cells stimulated production of PGE and PGF and increased their cyclooxygenase 2 mRNA expression. The production of prostaglandins was abrogated by an LPS antagonist. In addition, estradiol and progesterone inhibited the production of PGE and PGF in response to LPS, indicating a role for steroid hormones in the response to bacterial infection. For the first time, Toll-like receptor 4 mRNA and CD14 mRNA and protein were detected in bovine endometrial stromal and epithelial cells by RT-PCR and flow cytometry. In conclusion, epithelial and stromal cells detect and respond to bacteria, which modulate their endocrine function.

Clinical evaluation of postpartum vaginal mucus reflects uterine bacterial infection and the immune response in cattle

Bacteria contaminate the uterus of most dairy cattle after parturition and endometritis causes infertility. An endometritis score can be ascribed based on the vaginal mucus character and odour but it is not clear if the clinical score reflects the number of uterine bacteria or the inflammatory response. The present study tested the hypothesis that clinical evaluation of endometritis reflects the number of bacteria present in the uterus, and the acute phase protein response. Swabs (n = 328) were collected from the uterine lumen of dairy cattle, 21 and 28 days postpartum, vaginal mucus was scored for character and odour, and blood samples collected for acute phase protein measurement. Bacteria were identified following aerobic and anaerobic culture, and the bacterial growth density was scored semi-quantitatively. When bacteria were categorised by their expected pathogenic potential in the uterus, purulent or fetid odour vaginal mucus was associated with the growth density of pathogenic bacteria but not opportunist contaminants. When bacteria were analysed independently, Arcanobacterium pyogenes, Proteus and Fusobacterium necrophorum growth densities were associated with mucopurulent or purulent vaginal mucus. The bacterial growth densities for A. pyogenes, Escherichia coli, non-hemolytic Streptococci, and Mannheimia haemolytica were associated with a fetid mucus odour. Peripheral plasma concentrations of alpha(1)-acid glycoprotein were higher if there was a fetid compared with a normal vaginal mucus odour (1.50 +/- 0.09 mg/mL versus 1.05 +/- 0.02 mg/mL, P < 0.001), but did not differ significantly between vaginal mucus character scores. The evaluation of the character and odour of vaginal mucus reflects the number of bacteria in the uterus, and the acute phase protein response.

Influence of baseline hematocrit on between-subject BOLD signal change using gradient echo and asymmetric spin echo EPI

The dependence of BOLD signal change (BSC) on baseline hematocrit is in the process of being characterized, primarily using conventional Gradient Echo (GE) echo planar imaging (EPI). We describe the first empiric exploration of this relationship using, in addition to GE, Spin Echo (SE) and two Asymmetric Spin Echo EPI sequences (ASE10 and ASE20), which are less susceptible to large vessel noise. Motor cortex BSC was measured (N = 17) and regressed against hematocrit and hemoglobin concentration using linear and non-linear functions. GE measurements of BSC yielded a positive linear relationship (r(2) = 0.240, p = 0.0459) whereas a positive non-linear relationship was observed using ASE10 (r(2) = 0.571, p = 0.0146). Results suggest that between-subjects BSC is significantly dependent on baseline hematocrit. The nature of dependence, and implications for quantitative studies vary with the vessel size selectivity of the imaging sequence, and with the effect of hematocrit on blood viscosity in the imaged vessels.

Severe panniculitis caused by homozygous ZZ alpha1-antitrypsin deficiency treated successfully with human purified enzyme (Prolastin)

Severe panniculitis caused by alpha1-antitrypsin deficiency is very rare even though the ZZ phenotype occurs in 1 : 3500 of the population of northern Europe. We describe a 33-year-old woman with rapidly progressing panniculitis and extensive skin necrosis with multiple life-threatening complications. Initial treatment followed by maintenance therapy with human purified enzyme (Prolastin, Bayer, Bridgend, U.K.) has been life-saving.

Effect of slice orientation on reproducibility of fMRI motor activation at 3 Tesla

The effect of slice orientation on reproducibility and sensitivity of 3T fMRI activation using a motor task has been investigated in six normal volunteers. Four slice orientations were used; axial, oblique axial, coronal and sagittal. We applied analysis of variance (ANOVA) to suprathreshold voxel statistics to quantify variability in activation between orientations and between subjects. We also assessed signal detection accuracy in voxels across the whole brain by using a finite mixture model to fit receiver operating characteristic (ROC) curves to the data. Preliminary findings suggest that suprathreshold cluster characteristics demonstrate high motor reproducibility across subjects and orientations, although a significant difference between slice orientations in number of activated voxels was demonstrated in left motor cortex but not cerebellum. Subtle inter-orientation differences are highlighted in the ROC analyses, which are not obvious by ANOVA; the oblique axial slice orientation offers the highest signal detection accuracy, whereas coronal slices give the lowest.

Identification of an N-cadherin motif that can interact with the fibroblast growth factor receptor and is required for axonal growth

In this study, we show that the neurite outgrowth response stimulated by N-cadherin is inhibited by a recently developed and highly specific fibroblast growth factor receptor (FGFR) antagonist. To test whether the N-cadherin response also requires FGF function, we developed peptide mimetics of the receptor binding sites on FGFs. Most mimetics inhibit the neurite outgrowth response stimulated by FGF in the absence of any effect on the N-cadherin response. The exceptions to this result were two mimetics of a short FGF1 sequence, which has been shown to interact with the region of the FGFR containing the histidine-alanine-valine motif. These peptides inhibited FGF and N-cadherin responses with similar efficacy. The histidine-alanine-valine region of the FGFR has previously been implicated in the N-cadherin response, and a candidate interaction site has been identified in extracellular domain 4 of N-cadherin. We now show that antibodies directed to this site on N-cadherin inhibit the neurite outgrowth response stimulated by N-cadherin, and peptide mimetics of the site inhibit N-cadherin and FGF responses. Thus, we can conclude that N-cadherin contains a novel motility motif in extracellular domain 4, and that peptide mimetics of this motif can interact with the FGFR.

Local similarity in evolutionary rates extends over whole chromosomes in human-rodent and mouse-rat comparisons: implications for understanding the mechanistic basis of the male mutation bias

The sex chromosomes and autosomes spend different times in the germ line of the two sexes. If cell division is mutagenic and if the sexes differ in number of cell divisions, then we expect that sequences on the X and Y chromosomes and autosomes should mutate at different rates. Tests of this hypothesis for several mammalian species have led to conflicting results. At the same time, recent evidence suggests that the chromosomal location of genes on autosomes affects their rate of evolution at synonymous sites. This suggests a mutagenic source different from germ cell replication. To correctly interpret the previous estimates of male mutation bias, it is crucial to understand the degree and range of this local similarity. With a carefully chosen randomization protocol, local similarity in synonymous rates of evolution can be detected in human-rodent and mouse-rat comparisons. However, the synonymous-site similarity in the mouse-rat comparison remains weak. Simulations suggest that this difference between the mouse-human and the mouse-rat comparisons is not artifactual and that there is therefore a difference between humans and rodents in the local patterns of mutation or selection on synonymous sites (conversely, we show that the previously reported absence of a local similarity in nonsynonymous rates of evolution in the human-rodent comparison was a methodological artifact). We show that linkage effects have a long-range component: not one in a million random genomes shows such levels of autosomal heterogeneity. The heterogeneity is so great that more autosomes than expected by chance have rates of synonymous evolution comparable with that of the X chromosome. As autosomal heterogeneity cannot be owing to different times spent in the germ line, this demonstrates that the dominant determiner of synonymous rates of evolution is not, as has been conjectured, the time spent in the male germ line.

Relaxin inhibits effective collagen deposition by cultured hepatic stellate cells and decreases rat liver fibrosis in vivo

BACKGROUND

Following liver injury, hepatic stellate cells (HSC) transform into myofibroblast-like cells (activation) and are the major source of type I collagen and the potent collagenase inhibitors tissue inhibitors of metalloproteinases 1 and 2 (TIMP-1 and TIMP-2) in the fibrotic liver. The reproductive hormone relaxin has been reported to reduce collagen and TIMP-1 expression by dermal and lung fibroblasts and thus has potential antifibrotic activity in liver fibrosis.

AIMS

To determine the effects of relaxin on activated HSC.

METHODS

Following isolation, HSC were activated by culture on plastic and exposed to relaxin (1-100 ng/ml). Collagen deposition was determined by Sirius red dye binding and radiolabelled proline incorporation. Matrix metalloproteinase (MMP) and TIMP expression were assessed by zymography and northern analysis. Transforming growth factor beta1 (TGF-beta1) mRNA and protein levels were quantified by northern analysis and ELISA, respectively.

RESULTS

Exposure of activated HSC to relaxin resulted in a concentration dependent decrease in both collagen synthesis and deposition. There was a parallel decrease in TIMP-1 and TIMP-2 secretion into the HSC conditioned media but no change in gelatinase expression was observed. Northern analysis demonstrated that primary HSC, continuously exposed to relaxin, had decreased TIMP-1 mRNA expression but unaltered type I collagen, collagenase (MMP-13), alpha smooth muscle actin, and TGF-beta1 mRNA expression.

CONCLUSION

These data demonstrate that relaxin modulates effective collagen deposition by HSC, at least in part, due to changes in the pattern of matrix degradation.

Selective inhibition of fibroblast growth factor (FGF)-stimulated mitogenesis by a FGF receptor-1-derived phosphopeptide

The activated fibroblast growth factor receptor (FGFR)-1 is phosphorylated on five tyrosine residues outside the catalytic site. Although one such residue, Tyr730, is flanked by potential binding sites for phosphotyrosine-interacting molecules, a physiological role for this region is still controversial. We report that a cell-permeant phosphopeptide mimic of this site, FGFR730(p)Y, inhibits FGF-mediated mitogenesis in cells with no effect on responses stimulated by other growth factors. A similar phosphopeptide corresponding to the phospholipase Cgamma binding site on the receptor had no effect on the mitogenic response. The FGFR730(p)Y peptide did not inhibit phosphorylation of p90/FRS2 or Erk, suggesting that it does not act by inhibiting the Erk-kinase cascade. However, the FGFR730(p)Y peptide bound Shc in a manner requiring both phosphorylated tyrosine and a putative PTB domain binding determinant. These data suggest that the peptide might inhibit mitogenesis by competing with the corresponding site on the FGFR for the ability to bind SHC.

Linear coupling between functional magnetic resonance imaging and evoked potential amplitude in human somatosensory cortex

The interpretation of task-induced functional imaging of the brain is critically dependent on understanding the relationship between observed blood flow responses and the underlying neuronal changes. However, the exact nature of this neurovascular coupling relationship remains unknown. In particular, it is unclear whether blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) responses principally reflect neuronal synaptic activity. In order to address this issue directly in humans, we measured the increase in somatosensory evoked potential amplitude and fMRI BOLD changes to increases in intensity of median nerve electrical stimulation in five healthy non-anaesthetized subjects. We found that mean N20-P22 amplitudes increased significantly with stimulus intensity in all subjects, as did fMRI BOLD percentage signal intensity change. Moreover, the intensity of the BOLD signal was found to correlate linearly with evoked potential amplitude in four of the five subjects studied. This suggests that the BOLD response correlates with synchronized synaptic activity, which is the major energy consuming process of the cortex.

Distribution of the interleukin-8 receptors, CXCR1 and CXCR2, in inflamed gut tissue

There is increasing evidence to suggest that the potent neutrophil chemoattractant interleukin-8 (IL-8) has an important role in the pathogenesis of inflammatory bowel disease. IL-8 mediates its actions via two cell surface receptors, CXCR1 and CXCR2. This paper describes the distribution of these IL-8 receptors in the normal gastrointestinal tract and how this is modified in ulcerative colitis (UC). Paraffin-embedded colonic resection specimens were stained with monoclonal antibodies directed against CXCR1 and CXCR2 in ten cases of total UC, 16 cases of appendicitis, and 11 histologically normal sections. A semiquantitative scale of 0-4 was used to assess the proportion and intensity of positively stained cells within certain defined areas of tissue. A comparative assessment was made of the distribution of various cell populations. Dual immunostaining was used to confirm the phenotype of positively staining cells. In the histologically normal colon, the antibody against CXCR1 stained a subpopulation of macrophages deep to the epithelium and germinal centre lymphocytes. A similar pattern of staining was seen in acute appendicitis, with in addition some positively stained neutrophil polymorphs. In UC, there was up-regulation of CXCR1, with a striking increase in positively stained macrophages throughout the mucosa and of B and T lymphocytes outside the germinal centre areas. There was also intense up-regulation of CXCR1 expression by the luminal epithelium, reflected in the epithelial staining score (mean+/-SE=1.8+/-0.44 for UC cases, vs. 0.23+/-0.16 for controls and 0.25+/-0.14 for acute appendicitis). CXCR2 was only expressed on a small population of lamina propria mononuclear cells and crypt epithelial cells, with no significant differences observed between the groups. These results suggest that IL-8 may, through CXCR1, have a role beyond neutrophil recruitment in mediating the immune response in UC and that this is not merely a consequence of the acute inflammation seen in UC.

Distribution of the interleukin-8 receptors, CXCR1 and CXCR2, in inflamed gut tissue

There is increasing evidence to suggest that the potent neutrophil chemoattractant interleukin-8 (IL-8) has an important role in the pathogenesis of inflammatory bowel disease. IL-8 mediates its actions via two cell surface receptors, CXCR1 and CXCR2. This paper describes the distribution of these IL-8 receptors in the normal gastrointestinal tract and how this is modified in ulcerative colitis (UC). Paraffin-embedded colonic resection specimens were stained with monoclonal antibodies directed against CXCR1 and CXCR2 in ten cases of total UC, 16 cases of appendicitis, and 11 histologically normal sections. A semiquantitative scale of 0-4 was used to assess the proportion and intensity of positively stained cells within certain defined areas of tissue. A comparative assessment was made of the distribution of various cell populations. Dual immunostaining was used to confirm the phenotype of positively staining cells. In the histologically normal colon, the antibody against CXCR1 stained a subpopulation of macrophages deep to the epithelium and germinal centre lymphocytes. A similar pattern of staining was seen in acute appendicitis, with in addition some positively stained neutrophil polymorphs. In UC, there was up-regulation of CXCR1, with a striking increase in positively stained macrophages throughout the mucosa and of B and T lymphocytes outside the germinal centre areas. There was also intense up-regulation of CXCR1 expression by the luminal epithelium, reflected in the epithelial staining score (mean+/-SE=1.8+/-0.44 for UC cases, vs. 0.23+/-0.16 for controls and 0.25+/-0.14 for acute appendicitis). CXCR2 was only expressed on a small population of lamina propria mononuclear cells and crypt epithelial cells, with no significant differences observed between the groups. These results suggest that IL-8 may, through CXCR1, have a role beyond neutrophil recruitment in mediating the immune response in UC and that this is not merely a consequence of the acute inflammation seen in UC.

Covariation of GC content and the silent site substitution rate in rodents: implications for methodology and for the evolution of isochores

Many attempts to test selectionist and neutralist models employ estimates of synonymous (Ks) and non-synonymous (Ka) substitution rates of orthologous genes. For example, a stronger Ka-Ks correlation than expected under neutrality has been argued to indicate a role for selection and the absence of a Ks-GC4 correlation has been argued to be inconsistent with neutral models for isochore evolution. However, both of these results, we have shown previously, are sensitive to the method by which Ka and Ks are estimated. Using a maximum likelihood (ML) estimator (GY94) we found a positive correlation between Ks and GC4 and only a weak correlation between Ka and Ks, lower than expected under neutral expectations. This ML method is computationally slow. Recently, a new ad hoc approximation of this ML method has been provided (YN00). This is effectively an extension of Li's protocol but that also allows for codon usage bias. This method is computationally near-instantaneous and therefore potentially of great utility for analysis of large datasets. Here we ask whether this method might have such applicability. To this end we ask whether it too recovers the two unusual results. We report that when the ML and earlier ad hoc methods disagree, YN00 recovers the results described by the ML methods, i.e. a positive correlation between GC4 and Ks and only a weak correlation between Ks and Ka. If the ML method can be trusted, then YN00 can also be considered an adequately reliable method for analysis of large datasets. Assuming this to be so we also analyze further the patterns. We show, for example, that the positive correlation between GC4 and Ks is probably in part a mutational bias, there being more methyl induced CpG-->TpG mutations in GC rich regions. As regards the evolution of isochores, it seems inappropriate to use the claimed lack of a correlation between GC and Ks as definitive evidence either against or for any model. If the positive correlation is real then, we argue, this is hard to reconcile with the biased gene conversion model for isochore formation as this predicts a negative correlation.

Distribution of the interleukin-8 receptors, CXCR1 and CXCR2, in inflamed gut tissue

There is increasing evidence to suggest that the potent neutrophil chemoattractant interleukin-8 (IL-8) has an important role in the pathogenesis of inflammatory bowel disease. IL-8 mediates its actions via two cell surface receptors, CXCR1 and CXCR2. This paper describes the distribution of these IL-8 receptors in the normal gastrointestinal tract and how this is modified in ulcerative colitis (UC). Paraffin-embedded colonic resection specimens were stained with monoclonal antibodies directed against CXCR1 and CXCR2 in ten cases of total UC, 16 cases of appendicitis, and 11 histologically normal sections. A semiquantitative scale of 0-4 was used to assess the proportion and intensity of positively stained cells within certain defined areas of tissue. A comparative assessment was made of the distribution of various cell populations. Dual immunostaining was used to confirm the phenotype of positively staining cells. In the histologically normal colon, the antibody against CXCR1 stained a subpopulation of macrophages deep to the epithelium and germinal centre lymphocytes. A similar pattern of staining was seen in acute appendicitis, with in addition some positively stained neutrophil polymorphs. In UC, there was up-regulation of CXCR1, with a striking increase in positively stained macrophages throughout the mucosa and of B and T lymphocytes outside the germinal centre areas. There was also intense up-regulation of CXCR1 expression by the luminal epithelium, reflected in the epithelial staining score (mean+/-SE=1.8+/-0.44 for UC cases, vs. 0.23+/-0.16 for controls and 0.25+/-0.14 for acute appendicitis). CXCR2 was only expressed on a small population of lamina propria mononuclear cells and crypt epithelial cells, with no significant differences observed between the groups. These results suggest that IL-8 may, through CXCR1, have a role beyond neutrophil recruitment in mediating the immune response in UC and that this is not merely a consequence of the acute inflammation seen in UC.

The proteins of linked genes evolve at similar rates

Much more variation in the rate of protein evolution occurs than is expected by chance. But why some proteins evolve rapidly but others slowly is poorly resolved. It was proposed, for example, that essential genes might evolve slower than dispensable ones, but this is not the case; and despite earlier claims, rates of evolution do not correlate with amino-acid composition. A few patterns have been found: proteins involved in antagonistic co-evolution (for example, immune genes, parasite antigens and reproductive conflict genes) tend to be rapidly evolving, and there is a correlation between the rate of protein evolution and the mutation rate of the gene. Here we report a new highly statistically significant predictor of a protein's rate of evolution, and show that linked genes have similar rates of protein evolution. There is also a weaker similarity of rates of silent site evolution (see ref. 13), which appears to be, in part, a consequence of the similarity in rates of protein evolution. The similarity in rates of protein evolution is not a consequence of underlying mutational patterns. A pronounced negative correlation between the rate of protein evolution and a covariant of the recombination rate indicates that rates of protein evolution possibly reflect, in part, the local strength of stabilizing selection.

CAMs and axonal growth: a critical evaluation of the role of calcium and the MAPK cascade

Calcium has long been recognized as a key player in the control of axonal growth and guidance. Recent studies lend support to this pivotal role by showing that local changes in calcium can directly induce the formation of filopodia in vivo and turn a growth cone in vitro. Under normal growth conditions, the L1 adhesion molecule has now been shown to induce local rather than global changes in calcium in growth cones, and this suggests that cell adhesion molecules (CAMs) use localized calcium transients to stimulate axonal growth and guidance. A number of recent reports have demonstrated that the neurite outgrowth response stimulated by L1 and other adhesion molecules (NCAM, N-cadherin, laminin) also depends in part upon the integrity of the MAPK cascade in cells. In this review we consider the recent data and suggest that calcium and the MAPK cascade might be required for very distinct growth cone functions. Finally, we will consider the contentious issue of how the above CAMs activate signaling cascades in growth cones and review the recently available data that support the hypothesis that at least one of these CAMs (N-cadherin) might promote growth cone motility by directly interacting with the FGFR in growth cones.

The molecular evolution of signal peptides

Signal peptides direct mature peptides to their appropriate cellular location, after which they are cleaved off. Very many random alternatives can serve the same function. Of all coding sequences, therefore, signal peptides might come closest to being neutrally evolving. Here we consider this issue by examining the molecular evolution of 76 mouse-rat orthologues, each with defined signal peptides. Although they do evolve rapidly, they evolve about half as fast as neutral sequences. This indicates that a substantial proportion of mutations must be under stabilizing selection. A few putative signal sequences lack a hydrophobic core and these tend to be more slowly evolving than others, indicating even stronger stabilizing selection. However, closer scrutiny suggests that some of these represent mis-annotations in GenBank. It is also likely that some of the substitutions are not neutral. We find, for example, that the rate of protein evolution correlates with that of the mature peptide. This may be a result of compensatory evolution. We also find that signal peptides of immune genes tend to be faster evolving than the average, which suggests an association with antagonistic co-evolution. Previous reports also indicated that the signal peptide of the imprinted gene, Igf2r, is also unusually fast evolving. This, it was hypothesized, might also be indicative of antagonistic co-evolution. Comparison of Igf2r's signal peptide evolution shows that, although it is not an outlier, its rate of evolution is comparable to that of many of the faster evolving immune system signal sequences and 5/6 of the amino acid changes do not conserve hydrophobicity. This is at least suggestive that there is something unusual about Igf2r's signal sequence.

Increased expression of connective tissue growth factor in fibrotic human liver and in activated hepatic stellate cells

BACKGROUND/AIMS

Connective tissue growth factor is a recently described mitogenic protein implicated in a variety of fibrotic disorders. Connective tissue growth factor may be a downstream mediator of the pro-fibrotic and mitogenic actions of transforming growth factor-beta, promoting extracellular matrix deposition and fibrogenesis. As transforming growth factor-beta is considered important to the pathogenesis of hepatic fibrosis, we examined the possible contribution of connective tissue growth factor to this process.

METHODS

Connective tissue growth factor expression was examined in normal and fibrotic human and rat livers using RT-PCR and ribonuclease protection assays, and in primary cultures of rat hepatic stellate cells by Northern and Western blotting.

RESULTS

Ribonuclease protection assays demonstrated connective tissue growth factor mRNA was increased 3-5-fold in human fibrotic liver compared with normal. RT-PCR showed this mRNA was increased in carbon-tetrachloride-treated rat liver. Northern analysis showed connective tissue growth factor mRNA was increasingly expressed during progressive activation of cultured rat hepatic stellate cells. Western analysis confirmed that freshly isolated hepatic stellate cells secreted relatively little connective tissue growth factor compared with hepatic stellate cells activated in culture. Hepatic stellate cells stimulated with transforming growth factor-beta showed increased expression of connective tissue growth factor mRNA and protein.

CONCLUSIONS

Connective tissue growth factor mRNA is consistently upregulated in human liver cirrhosis of various aetiologies, supporting a role for this growth factor in hepatic fibrogenesis. Our studies suggest that hepatic stellate cells may be an important source of hepatic connective tissue growth factor in vivo, particularly following stimulation with transforming growth factor-beta.

INP, a novel N-cadherin antagonist targeted to the amino acids that flank the HAV motif

The classical cadherins are homophilic binding molecules that play fundamental roles in several biological processes, including axonal growth and synaptic plasticity. The structures of the amino-terminal homophilic binding domains of N-cadherin and E-cadherin have been resolved. However, the mechanisms that govern cadherin binding and specificity remain contentious. In the present study we have used a peptide competition approach to probe for small linear determinants of cadherin binding. We demonstrate that a linear peptide mimetic of a short sequence in ECD1 of N-cadherin (INPISGQ) functions as a highly specific and potent antagonist of N-cadherin function with an IC(50) value of approximately 15 microM. Peptide mimetics of the corresponding motif in chick R-cadherin also inhibited N-cadherin function, albeit with lower efficacy. In contrast, peptide mimetics of the corresponding motif in E- or P-cadherin failed to inhibit N-cadherin function. A short cyclic peptide that contained only the INP motif from N-cadherin was also a potent N-cadherin antagonist (IC(50) approximately 15 microM). Analysis of existing crystal structures suggests that the peptides are likely to antagonize N-cadherin function by binding to the region that flanks the HAV motif at the adhesion dimer interface.

Incidence and types of adverse events and negligent care in Utah and Colorado

BACKGROUND

The ongoing debate on the incidence and types of iatrogenic injuries in American hospitals has been informed primarily by the Harvard Medical Practice Study, which analyzed hospitalizations in New York in 1984. The generalizability of these findings is unknown and has been questioned by other studies.

OBJECTIVE

We used methods similar to the Harvard Medical Practice Study to estimate the incidence and types of adverse events and negligent adverse events in Utah and Colorado in 1992.

DESIGN AND SUBJECTS

We selected a representative sample of hospitals from Utah and Colorado and then randomly sampled 15,000 nonpsychiatric 1992 discharges. Each record was screened by a trained nurse-reviewer for 1 of 18 criteria associated with adverse events. If > or =1 criteria were present, the record was reviewed by a trained physician to determine whether an adverse event or negligent adverse event occurred and to classify the type of adverse event.

MEASURES

The measures were adverse events and negligent adverse events.

RESULTS

Adverse events occurred in 2.9+/-0.2% (mean+/-SD) of hospitalizations in each state. In Utah, 32.6+/-4% of adverse events were due to negligence; in Colorado, 27.4+/-2.4%. Death occurred in 6.6+/-1.2% of adverse events and 8.8+/-2.5% of negligent adverse events. Operative adverse events comprised 44.9% of all adverse events; 16.9% were negligent, and 16.6% resulted in permanent disability. Adverse drug events were the leading cause of nonoperative adverse events (19.3% of all adverse events; 35.1% were negligent, and 9.7% caused permanent disability). Most adverse events were attributed to surgeons (46.1%, 22.3% negligent) and internists (23.2%, 44.9% negligent).

CONCLUSIONS

The incidence and types of adverse events in Utah and Colorado in 1992 were similar to those in New York State in 1984. Iatrogenic injury continues to be a significant public health problem. Improving systems of surgical care and drug delivery could substantially reduce the burden of iatrogenic injury.