Ageing impairs the regenerative capacity of regulatory T cells in mouse central nervous system remyelination

Myelin regeneration (remyelination) is essential to prevent neurodegeneration in demyelinating diseases such as Multiple Sclerosis, however, its efficiency declines with age. Regulatory T cells (Treg) recently emerged as critical players in tissue regeneration, including remyelination. However, the effect of ageing on Treg-mediated regenerative processes is poorly understood. Here, we show that expansion of aged Treg does not rescue age-associated remyelination impairment due to an intrinsically diminished capacity of aged Treg to promote oligodendrocyte differentiation and myelination in male and female mice. This decline in regenerative Treg functions can be rescued by a young environment. We identified Melanoma Cell Adhesion Molecule 1 (MCAM1) and Integrin alpha 2 (ITGA2) as candidates of Treg-mediated oligodendrocyte differentiation that decrease with age. Our findings demonstrate that ageing limits the neuroregenerative capacity of Treg, likely limiting their remyelinating therapeutic potential in aged patients, and describe two mechanisms implicated in Treg-driven remyelination that may be targetable to overcome this limitation.

Characterizing Neutrophil Subtypes in Cancer Using scRNA Sequencing Demonstrates the Importance of IL1β/CXCR2 Axis in Generation of Metastasis-specific Neutrophils

Neutrophils are a highly heterogeneous cellular population. However, a thorough examination of the different transcriptional neutrophil states between health and malignancy has not been performed. We utilized single-cell RNA sequencing of human and murine datasets, both publicly available and independently generated, to identify neutrophil transcriptomic subtypes and developmental lineages in health and malignancy. Datasets of lung, breast, and colorectal cancer were integrated to establish and validate neutrophil gene signatures. Pseudotime analysis was used to identify genes driving neutrophil development from health to cancer. Finally, ligand-receptor interactions and signaling pathways between neutrophils and other immune cell populations in primary colorectal cancer and metastatic colorectal cancer were investigated. We define two main neutrophil subtypes in primary tumors: an activated subtype sharing the transcriptomic signatures of healthy neutrophils; and a tumor-specific subtype. This signature is conserved in murine and human cancer, across different tumor types. In colorectal cancer metastases, neutrophils are more heterogeneous, exhibiting additional transcriptomic subtypes. Pseudotime analysis implicates IL1β/CXCL8/CXCR2 axis in the progression of neutrophils from health to cancer and metastasis, with effects on T-cell effector function. Functional analysis of neutrophil-tumoroid cocultures and T-cell proliferation assays using orthotopic metastatic mouse models lacking Cxcr2 in neutrophils support our transcriptional analysis. We propose that the emergence of metastatic-specific neutrophil subtypes is driven by the IL1β/CXCL8/CXCR2 axis, with the evolution of different transcriptomic signals that impair T-cell function at the metastatic site. Thus, a better understanding of neutrophil transcriptomic programming could optimize immunotherapeutic interventions into early and late interventions, targeting different neutrophil states.

SIGNIFICANCE

We identify two recurring neutrophil populations and demonstrate their staged evolution from health to malignancy through the IL1β/CXCL8/CXCR2 axis, allowing for immunotherapeutic neutrophil-targeting approaches to counteract immunosuppressive subtypes that emerge in metastasis.

Whole-school interventions promoting student commitment to school to prevent substance use and violence: a systematic review

OBJECTIVES

Whole-school interventions that promote student commitment to school are a promising modality to reduce health inequalities through school-level change; however, evidence for the effectiveness of these interventions in improving policy-relevant health outcomes, such as substance use and violence, has not been comprehensively synthesised.

STUDY DESIGN

This was a systematic review and meta-analysis.

METHODS

We searched 20 databases and a range of other sources to identify randomised trials meeting our intervention definition and reporting substance use and violence outcomes. Extracted effect estimates were meta-analysed using robust variance estimation with random effects, separating effects <1 year from baseline and effects at or more than 1 year from baseline.

RESULTS

We included 18 evaluations with varying risk of bias. Pooled effects suggested significant impacts on short-term (odds ratio [OR] = 0.85, 95% confidence interval [CI] 0.76, 0.96) and long-term (OR = 0.79, 95% CI 0.65, 0.98) violence perpetration, short-term (OR = 0.84, 95% CI 0.72, 0.98) and long-term (OR = 0.85, 95% CI 0.73, 0.99) violence victimisation, and short-term (OR = 0.83, 95% CI 0.70, 0.97) and long-term (OR = 0.79, 95% CI 0.62, 0.998) substance use outcomes, with effects relatively stable between short-term and long-term analyses. Stratifying substance use meta-analyses by type (e.g. smoking, alcohol) did not impact results. All meta-analyses had substantial heterogeneity.

CONCLUSION

Although diverse in content, interventions appear effective with respect to the review outcomes and as a form of universal prevention. Future research should consider contextual contingencies in intervention effectiveness, given considerable policy and practice interest in these interventions and the need to support schools in effective decision-making as to intervention choice.

Single cell sequencing of neutrophils demonstrates phenotypic heterogeneity and functional plasticity in health, disease, and cancer

A vital constituent of innate immunity, neutrophils had previously been considered functionally rigid with a fixed, defined role in host pathogen response, in part due to their fleeting lifespan. However, that consensus opinion has changed with evidence of functional neutrophil plasticity in a range of diseases including cancer. Typically difficult to sequence due to their low level of transcriptomic activity, advances in single cell RNA sequencing has allowed for closer examination of the neutrophil transcriptome in humans and mouse models and their interaction with other immune system constituents, both in health and disease, allowing for description of neutrophil phenotypes beyond previous descriptions reliant upon microscopic appearance, surface marker expression, and function. Transcriptomic analysis shows that neutrophils develop and mature along a fixed trajectory, but their transcriptome varies based on maturity, the insult that has provoked release from the bone marrow, and the tissue to which they are recruited. Thus neutrophil heterogeneity increases with maturity, with immature neutrophils being more transcriptomically rigid. Here, we review work done in neutrophil single cell RNA sequencing in mice and humans in health and a range of disease states including coronavirus disease 2019 (COVID-19) infection, and solid cancers to provide a template for understanding neutrophil biology in context.

The Barts Health NHS Trust COVID-19 cohort: characteristics, outcomes and risk scoring of patients in East London

BACKGROUND: Barts Health National Health Service Trust (BHNHST) serves a diverse population of 2.5 million people in London, UK. We undertook a health services assessment of factors used to evaluate the risk of severe acute respiratory coronavirus 2 (SARS-CoV-2) infection.METHODS: Patients with confirmed polymerase chain reaction (PCR) test results admitted between 1 March and 1 August 2020 were included, alongwith clinician-diagnosed suspected cases. Prognostic factors from the 4C Mortality score and 4C Deterioration scores were extracted from electronic health records and logistic regression was used to quantify the strength of association with 28-day mortality and clinical deterioration using national death registry linkage.RESULTS: Of 2783 patients, 1621 had a confirmed diagnosis, of whom 61% were male and 54% were from Black and Minority Ethnic groups; 26% died within 28 days of admission. Mortality was strongly associated with older age. The 4C mortality score had good stratification of risk with a calibration slope of 1.14 (95% CI 1.01-1.27). It may have under-estimated mortality risk in those with a high respiratory rate or requiring oxygen.CONCLUSION: Patients in this diverse patient cohort had similar mortality associated with prognostic factors to the 4C score derivation sample, but survival might be poorer in those with respiratory failure.

CCN3 is dynamically regulated by treatment and disease state in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated disease that damages myelin in the central nervous system (CNS). We investigated the profile of CCN3, a known regulator of immune function and a potential mediator of myelin regeneration, in multiple sclerosis in the context of disease state and disease-modifying treatment.

METHODS

CCN3 expression was analysed in plasma, immune cells, CSF and brain tissue of MS patient groups and control subjects by ELISA, western blot, qPCR, histology and in situ hybridization.

RESULTS

Plasma CCN3 levels were comparable between collective MS cohorts and controls but were significantly higher in progressive versus relapsing-remitting MS and between patients on interferon-β versus natalizumab. Higher body mass index was associated with higher CCN3 levels in controls as reported previously, but this correlation was absent in MS patients. A significant positive correlation was found between CCN3 levels in matched plasma and CSF of MS patients which was absent in a comparator group of idiopathic intracranial hypertension patients. PBMCs and CD4+ T cells significantly upregulated CCN3 mRNA in MS patients versus controls. In the CNS, CCN3 was detected in neurons, astrocytes and blood vessels. Although overall levels of area immunoreactivity were comparable between non-affected, demyelinated and remyelinated tissue, the profile of expression varied dramatically.

CONCLUSIONS

This investigation provides the first comprehensive profile of CCN3 expression in MS and provides rationale to determine if CCN3 contributes to neuroimmunological functions in the CNS.

Retrospective study found that outpatient care for infants exposed to drugs during pregnancy was sustainable and safe

AIM

We determined the safety, feasibility and sustainability of an outpatient model of care for infants exposed to intra-uterine drugs.

METHODS

This was a retrospective chart review of 774 drug-exposed infants born between 1998 and 2016 at the Royal Hospital for Women, Sydney, Australia.

RESULTS

Most (86%) of the mothers used multiple drugs, including opioids (58%). More than three-quarters (78%) of the infants were born full term at a mean gestation of 38 weeks and hospitalised for a median of seven days. This rose to 14 days if they were medicated for neonatal abstinence syndrome (NAS). Most of the NAS patients (83%) were discharged on medication, namely morphine, and the median duration of NAS treatment was 76 (interquartile range 35-120). Three medication errors occurred: two extra doses of phenobarbitone and one infant weaned off morphine faster than prescribed. No infants were rehospitalised for NAS. Four died from sudden infant death syndrome at 2.2-5.8 months after discharge and one drowned at 15 months. None were medicated at the time of death.

CONCLUSION

Outpatient care for drug-exposed infants was sustainable and had low complication rates, even for those with NAS. The optimum duration of follow-up and impact on hospital costs should be examined.

Canadian stroke best practice recommendations: Secondary prevention of stroke, sixth edition practice guidelines, update 2017

The 2017 update of The Canadian Stroke Best Practice Recommendations for the Secondary Prevention of Stroke is a collection of current evidence-based recommendations intended for use by clinicians across a wide range of settings. The goal is to provide guidance for the prevention of ischemic stroke recurrence through the identification and management of modifiable vascular risk factors. Recommendations include those related to diagnostic testing, diet and lifestyle, smoking, hypertension, hyperlipidemia, diabetes, antiplatelet and anticoagulant therapies, carotid artery disease, atrial fibrillation, and other cardiac conditions. Notable changes in this sixth edition include the development of core elements for delivering secondary stroke prevention services, the addition of a section on cervical artery dissection, new recommendations regarding the management of patent foramen ovale, and the removal of the recommendations on management of sleep apnea. The Canadian Stroke Best Practice Recommendations include a range of supporting materials such as implementation resources to facilitate the adoption of evidence to practice, and related performance measures to enable monitoring of uptake and effectiveness of the recommendations. The guidelines further emphasize the need for a systems approach to stroke care, involving an interprofessional team, with access to specialists regardless of patient location, and the need to overcome geographic barriers to ensure equity in access within a universal health care system.

Regulatory T cells promote myelin regeneration in the central nervous system

Regeneration of CNS myelin involves differentiation of oligodendrocytes from oligodendrocyte progenitor cells. In multiple sclerosis, remyelination can fail despite abundant oligodendrocyte progenitor cells, suggesting impairment of oligodendrocyte differentiation. T cells infiltrate the CNS in multiple sclerosis, yet little is known about T cell functions in remyelination. We report that regulatory T cells (T_reg) promote oligodendrocyte differentiation and (re)myelination. T_reg-deficient mice exhibited substantially impaired remyelination and oligodendrocyte differentiation, which was rescued by adoptive transfer of T_reg. In brain slice cultures, T_reg accelerated developmental myelination and remyelination, even in the absence of overt inflammation. T_reg directly promoted oligodendrocyte progenitor cell differentiation and myelination in vitro. We identified CCN3 as a T_reg-derived mediator of oligodendrocyte differentiation and myelination in vitro. These findings reveal a new regenerative function of T_reg in the CNS, distinct from immunomodulation. Although the cells were originally named 'T_reg' to reflect immunoregulatory roles, this also captures emerging, regenerative T_reg functions.

Cannabis, the pregnant woman and her child: weeding out the myths

To review and summarise the literature reporting on cannabis use within western communities with specific reference to patterns of use, the pharmacology of its major psychoactive compounds, including placental and fetal transfer, and the impact of maternal cannabis use on pregnancy, the newborn infant and the developing child. Review of published articles, governmental guidelines and data and book chapters. Although cannabis is one of the most widely used illegal drugs, there is limited data about the prevalence of cannabis use in pregnant women, and it is likely that reported rates of exposure are significantly underestimated. With much of the available literature focusing on the impact of other illicit drugs such as opioids and stimulants, the effects of cannabis use in pregnancy on the developing fetus remain uncertain. Current evidence indicates that cannabis use both during pregnancy and lactation, may adversely affect neurodevelopment, especially during periods of critical brain growth both in the developing fetal brain and during adolescent maturation, with impacts on neuropsychiatric, behavioural and executive functioning. These reported effects may influence future adult productivity and lifetime outcomes. Despite the widespread use of cannabis by young women, there is limited information available about the impact perinatal cannabis use on the developing fetus and child, particularly the effects of cannabis use while breast feeding. Women who are using cannabis while pregnant and breast feeding should be advised of what is known about the potential adverse effects on fetal growth and development and encouraged to either stop using or decrease their use. Long-term follow-up of exposed children is crucial as neurocognitive and behavioural problems may benefit from early intervention aimed to reduce future problems such as delinquency, depression and substance use.

Neonatal short bowel syndrome as a model of intestinal failure: physiological background for enteral feeding

Intestinal failure (IF) is a well identified clinical condition, which is characterised by the reduction of functional gut capacity below the minimum needed for adequate digestion and absorption of nutrients for normal growth in children. Short bowel syndrome (SBS) is the leading cause of IF in neonates, infants and young children usually as a result of extensive intestinal resection during the neonatal period. Simultaneously maintaining optimal nutritional status and achieving intestinal adaptation is a clinical challenge in short bowel patients. Both growth and development of the child as well as gut adaptation should be considered synergistically as primary outcome parameters. Enteral nutrition (EN) can be introduced orally and/or by tube feeding (TF). Several controversies over nutritional treatment of children with SBS related intestinal failure remain. As reported from different centres around the world, most practices are more "experienced based" rather than "evidence based". This is partly due to the small number of patients with this condition. This review (based on a consensus) discusses the physiological principles and nutritional management, including the type of diet and route of delivery. Perspectives in optimizing intestinal adaptation and reducing the consequences of small intestinal bacterial overgrowth are also discussed.

The pars intermedia and the fetal pituitary-adrenal axis

The increased production of cortisol by the fetal adrenal gland at term acts as the trigger for parturition in some species. The fetal pituitary controls fetal adrenal function. However, ACTH is only one of a family of closely related peptides which derive from a common precursor and we have shown that although ACTH is the dominant form in the adult pituitary, the expression of the "family trees' is altered in the fetus. In the sheep, it is large-molecular-weight precursors and, in the primate, the smaller peptides such as alpha-MSH, CLIP, beta-MSH and beta-endorphin that predominate in fetal life and which may be responsible for fetal adrenal function. It is still unclear what causes the developmental change in the ACTH "family tree'. Since it may result from a change in pituitary function - from the peptides of the pars intermedia, in the fetus, to those of pars anterior, in the adult - we have studied these two lobes separately in pituitaries taken from adult and fetal sheep and monkeys. Our preliminary results suggest that the change may occur in the neurointermediate lobe in the primate, but that in the sheep the developmental changes occur in the anterior lobe.

Ovine placental eluate immunoglobulins recognise isologous and third party acid-treated trophoblast microvesicle antigens in vitro

Placental microvesicles were prepared from ovine placentae and immunoglobulins eluted with 0.5 M glycine buffer pH 2.5. The ability of eluate immunoglobulins to re-associate with isologous (self) and third party acidified microvesicles was tested by ELISA. Ovine placental immunoglobulins re-associated with isologous and third party acidified microvesicles suggesting that at least 2 types of antigenic epitopes I and II maybe expressed on the ovine placentae. Type I antigens may be present on placentae of all ovines while type II epitopes may be paternally derived, hence unique to each pregnancy. Analysis by SDS PAGE revealed the heavy and light chains of IgG at 57 and 27 kDa, respectively, together giving a relative molecular weight of 158 kDa. Results suggest that immunoglobulins produced to placental microvesicle antigens may be directed to some but not all antigenic epitopes expressed on the trophoblast, possibly defining a mechanism by which the foetus evades maternal immunological rejection.

Immunoglobulin G bound to ovine placenta is eluted by surgical cannulation and acid perfusion in situ

OBJECTIVE

To elute placental bound immunoglobulin G (IgG) in situ.

DESIGN

Laboratory based experimentation.

SETTING

Biological Sciences Department, The University of Newcastle Australia and the Department of Biochemistry, University of Nairobi, Kenya.

SUBJECTS

Twelve pregnant ewes 10 to 15 days before the onset of natural parturition.

RESULTS

Placental eluates were rich in IgG, and IgG2. The relative molecular weight of placental IgG was estimated at 158kDa by gel filtration chromatography. Analysis of eluate by SDS PAGE revealed the heavy and light chains of IgG at 57 and 27kDa respectively together giving a relative molecular weight of 168kDa.

CONCLUSION

Placental bound IgG may be crucial in immunology of pregnancy and together with the cognate antigen thereof may be useful as models for the study of maternal-fetal interaction in human pregnancy and in the development of experimental immunotherapy to immunologically compromised pregnancies in humans and livestock.

Human placental immunoglobulins show unique re-association patterns with isologous and third party acid treated trophoblast microvesicles in vitro

OBJECTIVE

To study re-association pattern of human placental eluate immunoglobulins with acid treated isologous and third party trophoblast derived placental microvesicles.

DESIGN

Laboratory based experimentation.

SETTING

Biological Sciences Department and Discipline for Reproductive Medicine University of Newcastle, Australia and the Department of Biochemistry, University of Nairobi, Kenya.

RESULTS

Placental eluate immunoglobulins re-associated with isologous and third party acidified microvesicles in three distinct patterns. I: eluate immunoglobulins re-associated more strongly with isologous and third party acid treated placental microvesicles, II: eluate immunoglobulins re-associated strongly with isologous but weakly with third party acid treated placental microvesicles, III: eluate immunoglobulins did not show preferential re-association with isologous and third party acid treated placental microvesicles.

CONCLUSION

Two types of antigenic epitopes I and II may be expressed on the human placentae. Type I antigens may be present on all human placentae while type II epitopes may be paternally derived hence unique to each pregnancy. Also, immunoglobulins produced to placental microvesicle antigens may be directed to some but not all antigenic epitopes expressed on the human placental trophoblast.

Dietary n-3 fatty acids alter the contractile response to thromboxane A(2) agonists of porcine coronary arteries

Dietary supplementation with marine fish oils rich in n-3 fatty acids reduces circulating thromboxane A(2) (TxA(2)). However, the effects on thomboxane A(2) receptor mediated vascular reactivity are uncertain. The aim of this study was to test the hypothesis that dietary modification of TxA(2) levels alters vascular responsiveness to TxA(2) analogues. Juvenile female white pigs were fed a diet enriched in either 5% (w/w) fish oil or beef tallow for 6 weeks. Serum and myocardial tissue levels of eicosapentaenoic and docosahexaenoic acid reached a plateau during this period. Vascular responses were measured in isolated coronary arterial rings with intact endothelium by isometric tension measurement. Arteries from pigs fed fish oil produced a greater maximum vasoconstrictor tension to the TxA(2) analogue U46619 than did rings from pigs fed beef tallow (120 +/- 6% compared to 92 +/- 8%, values represented as a percentage relative to the maximum vasoconstrictor effect obtained to KCl, regression analysis, analysis of variance, P </= 0.05). The vasoconstrictor potency of U46619 was similar in both treatment groups. The vasoconstrictor EC(50) was 10.3 (6.8-15.7) nmol/L (mean, 95% confidence interval) for fish oil and 9.5 (5.7-15.8) nmol/L for beef tallow treated animals. Changes in vascular responses to U46619 were associated with a fourfold difference in plasma thromboxane B(2) levels between treatment groups (12.1 +/- 2.6 pg/mL fish oil, 48.3 +/- 3.1 pg/mL beef tallow, Students' unpaired t-test P </= 0.05). Vasoconstrictor responses obtained to endothelin-1, KCl and 5-hydroxtryptamine and the vasodilator response to sodium nitroprusside were not different between treatment groups. Dietary manipulation of thromboxane A(2) levels by n-3 fatty acids alters vascular reactivity to U46619, possibly as a result of agonist-induced desensitization of thromboxane A(2) receptors.

Ovine and Human Placental IgG inhibit Human Natural Killer Cell Cytotoxicity in vitro

To determine the effect of ovine and human placental IgG on human Natural Killer (NK) cell cytotoxicity in vitro placental IgG was eluted at acidic pH and purified by ion exchange and subsequently by affinity chromatography on protein G and protein A sepharose columns. These antibodies were analysed for presense of IgG by immuno-electrophoresis and relative purity determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE). The effect of these antibodies on human NK cell cytotoxicity was investigated by slChromium Release Assay using human K562 cells as targets and human peripheral blood lymphocytes as effector cells. Both ovine and human placental IgG inhibited human NK cell cytotoxicity in a dose dependent manner. Placental IgG may down-regulate the cytotoxic effects of NK cells in vivo by competitively excluding the binding of NK cells to their respective targets on the trophoblast. Alternatively, these antibodies may themselves be toxic to NK cells. Either way, the presence of these antibodies on the placental trophoblast may prevent the binding of NK cells and subsequent immunological rejection of the fetal allograft. Also, ovine placental IgG may be functionally similar to its human counterpart and may therefore be suitable as a model for the study of maternal fetal interaction during pregnancy in humans.

Immunological Role of the Placenta, Blocking Factors and NK Cells in Post-implantation Pregnancy

The unexpected failure of the mother to immunologically reject the foetus is partly thought to result from immunological properties of the placenta. The placental trophoblast produces immunosuppressive factors including progesterone and blocking antibodies which together down-regulate maternal immune responses to the foetoplacental unit. This article reviews the post implantation immunology of pregnancy emphasizing the roles of placenta, blocking factors and natural killer (NK) cells.

Recurrent pregnancy losses and the role of immunotherapy

Post implantation pregnancy losses are psychologically and economically stressful to the childbearing population. The etiology in the vast majority of cases is unknown but is partly thought to result from a break-down of the maternal tolerance to the fetoplacental unit. Immunologically based therapy remains controversial but no alternative therapy is available at the moment. This article reviews the conceived immunological basis of recurrent pregnancy losses, discussing the controversies arising, and recommending the use of intravenous immunoglobulin, IVIg, in well controlled experiments for further clinical trials.

Cardiac (n-3) non-esterified fatty acids are selectively increased in fish oil-fed pigs following myocardial ischemia

The effect of fish oil supplementation on the nonesterified fatty acid (NEFA) concentration and composition in the normoxic and hypoxic myocardium of pigs was examined. Two groups of female pigs (n = 7) were fed a diet supplemented with either 5 g beef tallow/kg (as control) or 5 g fish oil/kg (MaxEPA) rich in (n-3) fatty acids. After 6 wk of supplementation, the pigs were anesthetized, hearts exposed by thoracotomy followed by occlusion of the left anterior descending artery. Normoxic and hypoxic regions of the heart were examined for NEFA concentration and composition by using a combination of thin layer and gas chromatography. Nonesterified (n-6) and (n-3) fatty acid concentration and composition differed significantly between the two groups in both the normoxic and hypoxic areas of the heart. Eicosapentaenoic and docosahexaenoic acid concentration in the NEFA fraction of the normoxic myocardium were higher in the fish oil group than in the beef tallow group (P < 0.001). In the fish oil-fed pigs, the (n-3) NEFA concentration was significantly higher in the hypoxic compared to the normoxic region of the heart. The fish oil-fed group had lower levels of arachidonic acid in the NEFA fraction compared to the beef tallow-fed group, whereas the hypoxic myocardium had higher levels of arachidonic acid, regardless of the dietary fat supplementation. Despite large differences in the proportions of saturated fatty acids in the experimental diets, there was little or no difference in the saturated fatty acid content of cardiac phospholipid and NEFA fractions. Following myocardial ischemia, (n-3) fatty acids in the NEFA fractions were selectively increased in the fish oil-fed pigs, implicating the possible role of nonesterified (n-3) polyunsaturated fatty acids in the prevention of arrhythmias.

A corticotropin-releasing hormone type I receptor antagonist delays parturition in sheep

In sheep, corticotropin-releasing hormone (CRH) can stimulate the fetal release of ACTH to produce a cortisol surge which leads to the onset of parturition. We tested the hypothesis that fetal CRH is a primary factor in the onset of parturition in sheep by using a Type I CRH receptor antagonist, antalarmin, to block the endogenous action of CRH. Pregnant ewes were cannulated at 130-135 days of gestation. Five catheters were placed into the amniotic sac, fetal femoral artery, fetal tarsal vein, maternal jugular vein and carotid artery. After 5 days' recovery, blood samples from maternal and fetal vessels were collected at the following times: a day before the start of infusion, at [-1, 0, 1, 2, 4, 8 and 24]h, on the first day of infusion, and thereafter daily throughout a 10-day infusion. Animals (n=6 per group) received infusions into a fetal vein of either a vehicle comprising 1:1 mixture of ethanol and polyethoxylated castor oil (Cremophor EL) or antalarmin (50 g/L) in the vehicle at a rate of 0.3 mL/h. The plasma samples were assayed for ACTH and cortisol using commercial RIA kits. Fetuses infused with vehicle delivered at a mean gestational age of 141.8 +/- 0.9 days compared with antalarmin-infused sheep at 148.8 +/- 1.6 days (P = 0.0036, unpaired Student's t-test). Fetal ACTH and cortisol did not change in the antalarmin-infused sheep after 3 days' infusion compared to significant increases in vehicle-infused sheep (P=0.004 and P = 0.016 respectively, ANOVA). These data show that CRH receptor antagonism in the fetus can delay the onset of parturition. It supports the hypothesis that hypothalamic CRH drives fetal production of ACTH and is essential for the onset of parturition triggered by a surge in fetal cortisol.

Elution and partial characterization of immunoglobulins bound to ovine placenta

Immunoglobulins were eluted from ovine placentae and characterized by immunoprecipitation, electrophoresis, western blotting and ELISA. IgG was shown to comprise the bulk of placental-bound immunoglobulins while smaller amounts of IgM and only trace amounts of IgA were demonstrated. Results suggest that ovine placental IgG eluted by surgical cannulation of the uterine blood vessels in situ is similar to that eluted from postpartum placentae in vitro, implying that there may be some transfer of antibodies across the maternal side of the placental barrier to the trophoblast. These antibodies are rich in IgG1 and IgG2, have a relative molecular weight of 158 kDa, and bind to an 80 kDa peptide prepared from pre-acidified ovine placental cotyledons. We propose that the binding of placental IgG to the 80 kDa antigen may prevent immunological rejection of the foetus by competitively excluding cytotoxic cells of maternal origin such as NK cells. Also, given that a similar antigen (80 kDa) has been reported in humans and equines, and shown to be saturated with IgG in term placentae, we propose that this antigen may be conserved in several mammalian species for reproductive purpose. Consequently, we suggest that the ovine placental IgG and the 80 kDa antigen may be suitable as models for the study of maternal-foetal interactions in mammalian pregnancies.

Prevention of cardiac arrhythmia by dietary (n-3) polyunsaturated fatty acids and their mechanism of action

The role of marine fish oil (n-3) polyunsaturated fatty acids in the prevention of fatal ventricular arrhythmia has been established in experimental animals. Prevention of arrhythmias arising at the onset of ischemia and reperfusion is important because if untreated, they result in sudden cardiac death. Animals supplemented with fish oils in their diet developed little or no ventricular fibrillation after ischemia was induced. Similar effects have also been observed in cultured neonatal cardiomyocytes. Several mechanisms have been proposed and studied to explain the antiarrhythmic effects of fish oil polyunsaturated fatty acids, but to date, no definite mechanism has been validated. The sequence of action of these mechanisms and whether more than one mechanism is involved is also not clear. Some of the mechanisms suggested to explain the antiarrhythmic action of fish oils include the incorporation and modification of cell membrane structure by (n-3) polyunsaturated fatty acids, their direct effect on calcium channels and cardiomyocytes and their role in eicosanoid metabolism. Other mechanisms that are currently being investigated include the role of (n-3) polyunsaturated fatty acids in cell signalling mediated through phosphoinositides and their effect on various enzymes and receptors. This article reviews these mechanisms and the antiarrhythmic studies using (n-3) polyunsaturated fatty acids.

Realtime ultrasound diagnosis over a wide-area network (WAN) using off-the-shelf components

A trial system was developed for relaying realtime ultrasound images from an obstetric referral centre, the Maitland Hospital, to a tertiary-care centre, the John Hunter Hospital in Newcastle. The sites were approximately 30 km apart and connected by a microwave link at 2 Mbit/s. The pilot study demonstrated the feasibility of realtime ultrasound transmission using commonly available components.

Ovine fetal umbilical artery Doppler systolic diastolic ratios and nitric oxide synthase

OBJECTIVE

To evaluate the effect of nitric oxide synthase activity inhibition on the fetal lamb umbilical artery flow velocity waveform.

METHODS

Five pregnant Corriedale cross ewes were operated on at 125-130 days' gestation. Fetal and maternal vascular catheters were inserted along with a Doppler flow meter cuff on the fetal common umbilical artery. Each fetus received a 40-minute intravenous (i.v.) infusion of N omega-nitro-D-arginine as a control, and then after a recovery period of 1 hour, a 40-minute i.v. infusion of N omega-nitro-L-arginine, an inhibitor of nitric oxide synthase activity. Maternal and fetal heart rate, blood pressure, blood gases, and fetal umbilical artery flow velocity waveforms were recorded at basal time and after the 40-minute i.v. infusions.

RESULTS

There were no differences in fetal or maternal heart rate, blood pressure, or blood gases with the infusion of the nitric oxide synthase inhibitor N omega-nitro-L-arginine. However, N omega-nitro-L-arginine caused a significant increase (41%) in the fetal umbilical artery flow velocity waveform systolic to diastolic ratio (S/D) above the baseline levels.

CONCLUSIONS

Inhibition of nitric oxide synthase activity in the lamb fetoplacental circulation with N omega-nitro-L-arginine is associated with an increase in the umbilical artery S/D.

Reducing hospital costs for the geriatric patient admitted from the emergency department: a randomized trial

OBJECTIVE

To test the impact of a geriatric evaluation and management model on the costs of acute hospital management of emergently admitted older adults.

DESIGN

Randomized controlled trial. Patients were followed in the acute hospital from admission through discharge. Results based on both univariate and multiple regression analyses.

SETTING

Private, nonprofit, academic medical center in a densely populated urban area.

PATIENTS

Adults 70 years of age and older admitted from the Emergency Department to the medicine service (non-ICU admission) who did not have an internist on staff at the admitting hospital. Of 141 randomized patients, 111 (78.7%) met eligibility criteria.

INTERVENTION

Assignment of a geriatrician and a social worker as the primary managing team during the hospital stay.

MAIN OUTCOME MEASURES

Length of stay, total cost of acute hospital care, cost of laboratory, pharmacy, and rehabilitation services.

RESULTS

Patients in the intervention group had 2.1 fewer days of hospitalization, but this shorter length of stay was not statistically significant (P = 0.108). There were no differences in mortality or discharge disposition. In risk-adjusted, multiple regression analysis the intervention group had a statistically significant lower predicted total cost per patient than the usual care group (-$2,544, P = 0.029); assignment to the intervention group was associated with a lower predicted cost per patient for laboratory (including cardiology graphics) services (P = 0.007) and pharmacy costs (P = 0.047).

CONCLUSIONS

When controlled for important predictors of expected resource use, care provided by a geriatric management team resulted in a significant reduction in the cost of hospitalization. A reduction in the cost of laboratory, cardiographic, and pharmacy services is consistent with the team's philosophy of defining the services needed based on goals related to functional outcomes.

An examination of Cyriax's passive motion tests with patients having osteoarthritis of the knee

BACKGROUND AND PURPOSE

We explored the construct validity and test-retest reliability of the passive motion component of the Cyriax soft tissue diagnosis system. We compared the hypothesized and actual patterns of restriction, end-feel, and pain/resistance sequence (P/RS) of 79 subjects with osteoarthritis (OA) of the knee and examined associations among these indicators of dysfunction and related constructs of joint motion, pain intensity, and chronicity.

SUBJECTS

Subjects had a mean age of 68.5 years (SD = 13.3, range = 28-95), knee stiffness for an average of 83.6 months (SD = 122.4, range = 1-612), knee pain averaging 5.6 cm (SD = 3.1, range = 0-10) on a 10-cm visual analogue scale, and at least a 10-degree limitation in passive range of motion (ROM) of the knee.

METHODS

Passive ROM (goniometry, n = 79), end-feel (n = 79), and P/RS during end-feel testing (n = 62) were assessed for extension and flexion on three occasions by one of four experienced physical therapists. Test-retest reliability was estimated for the 2-month period between the last two occasions.

RESULTS

Consistent with hypotheses based on Cyriax's assertions about patients with OA, most subjects had capsular end-feels for extension; subjects with tissue approximation end-feels for flexion had more flexion ROM than did subjects with capsular end-feels, and the P/RS was significantly correlated with pain intensity (rho = .35, extension; rho = .30, flexion). Contrary to hypotheses based on Cyriax's assertions, most subjects had noncapsular patterns, tissue approximation end-feels for flexion, and what Cyriax called pain synchronous with resistance for both motions. Pain intensity did not differ depending on end-feel. The P/RS was not correlated with chronicity (rho = .03, extension; rho = .01, flexion). Reliability, as analyzed by intraclass correlation coefficients (ICC[3,1]) and Cohen's kappa coefficients, was acceptable (> or = .80) or nearly acceptable for ROM (ICC = .71-.86, extension; ICC = .95-.99, flexion) but not for end-feel (kappa = .17, extension; kappa = .48, flexion) and P/RS (kappa = .36, extension; kappa = .34, flexion).

CONCLUSION AND DISCUSSION

The use of a quantitative definition of the capsular pattern, end-feels, and P/RS as indicators of knee OA should be reexamined. The validity of the P/RS as representing chronicity and the reliability of end-feel and the P/RS are questionable. More study of the soft tissue diagnosis system is indicated.

Differential strength decline in patients with osteoarthritis of the knee: revision of a hypothesis

A quadriceps-to-hamstring isometric peak torque ratio (Q/H ratio) of approximately 2.0 is considered necessary for appropriate knee biomechanics. Lower ratios may affect the function of persons with osteoarthritis (OA) and the progression of the disease. This study examined the isometric Q/H ratio in subjects with and without OA of the knee and explored the effect of age, pain, and joint enlargement on the ratio. Twenty-one pairs of subjects (OA, control) were matched on age (mean = 62.6 years; SD = 13.9), gender (F = 17, M = 4), and leg dominance (Dominant = 10, Nondominant = 11). Isometric quadriceps and hamstring peak torque, knee pain, and joint enlargement were measured. Paired t-tests demonstrated that the OA group had significantly lower quadriceps peak torque than the control group but did not have significantly lower hamstring peak torque or gravity-corrected isometric Q/H ratio. Age correlated with the ratio in subjects without OA (rho = -0.46; P = 0.03) but not in subjects with OA. Pain was not significantly correlated with the ratio in either group. Joint enlargement correlated with the ratio in the OA group (rho = -0.45; P = 0.03). The gravity-corrected isometric Q/H ratio appears to decrease with age in subjects without OA. In subjects with OA, the Q/H ratio appears not to change with disease, pain, or age. Joint enlargement may decrease the ratio and merits further study.

A randomized, controlled trial of arthroscopic surgery versus closed-needle joint lavage for patients with osteoarthritis of the knee

OBJECTIVE

To compare arthroscopic surgery and closed-needle joint lavage for patients with non-end-stage osteoarthritis (OA) of the knee under controlled, experimental conditions.

METHODS

Thirty-two subjects who met specific clinical, radiologic, medical, and rehabilitation criteria were randomized to receive arthroscopic surgery (n = 18) or joint lavage (n = 14). Outcome measures evaluated at baseline and at 3 and 12 months of followup included 3 standard clinical parameters, self-reported pain and functional status (by the Arthritis Impact Measurement Scales), 50-foot walk time, 2 global scales, and direct and indirect medical costs.

RESULTS

At 3 months of followup, there were no significant between-group differences in pain, self-reported and observed functional status, and patient and "blinded" physician global assessments. The arthroscopic procedure cost $3,840 more than did closed-needle joint lavage. After 1 year, there were no between-group differences in medication costs, utilization of medical services, or indirect costs related to employment or use of household help. After 1 year, 44% of subjects who underwent arthroscopy reported improvement and 58% of subjects who underwent joint lavage improved. Patients with tears of the anterior two-thirds of the medial meniscus or any lateral meniscus tear had a higher probability of improvement (by "blinded" physician assessment) after arthroscopic surgery (0.63) than did patients with other intraarticular pathology (0.20).

CONCLUSION

The search for and removal of soft tissue abnormalities via arthroscopic surgery does not appear justified for all patients with non-end-stage OA of the knee who fail to respond to conservative therapy, but it may be beneficial for certain subgroups.

Seeing the forest despite the trees. The benefit of exploratory data analysis to program evaluation research

In the present article, it is argued that there is a benefit to applying techniques of exploratory data analysis (EDA) to program evaluation. To exemplify this, an evaluation of a rehabilitation program for people with rheumatoid arthritis is presented. The perceived health status of patients receiving intensive rehabilitation services from a major rehabilitation institute was compared with that of patients receiving customary office-based care over an 18-month period. The data were analyzed in a conventional way (analysis of variance) and then by way of EDA techniques (graphic display of medians and boxplots). The conventional analysis suggested that all patients improved over time and that intensive rehabilitation services provided no particular benefit or harm. The exploratory analysis showed that the distribution of the outcome variable was patently nonnormal, thus casting doubt on the validity of the conventional analysis. The EDA further showed that the rehabilitation group lagged behind the comparison group for a year, with a precipitious improvement at the 18-month period. This suggests that a selection factor was operating (i.e., those in the rehabilitation group could have been sicker) or that the patients in the rehabilitation group were made more aware of their condition by the intensive health services they received. The EDA provided an important insight.

Differential muscle strength decline in osteoarthritis of the knee. A developing hypothesis

The ratio of quadriceps to hamstrings muscle strength (Q/H ratio) is important for the stability of the knee and for protection from excessive stress. The purpose of this study was to explore whether the Q/H ratio is altered in patients with osteoarthritis (OA). Subjects were 43 patients with physician-diagnosed OA of the knee (mean age, 65.61 years; SD, 12.74). Isometric knee flexor and extensor strength was measured with a hand-held dynamometer. Both muscle groups were weak, with relatively greater weakness in the quadriceps muscles. The mean Q/H ratio of 1.43 (SD, 0.39) was below ratios reported for young healthy adults (2.0). The low Q/H ratio might be caused by the inability to correct the measurement for gravity, but a liberal estimate of gravity correction raised the ratio only to 1.71 (SD, 0.47). The low Q/H ratio was probably not caused by physiologic changes due to aging, because the correlation between the ratio and age was low (-0.04). Since the correlation of the Q/H ratio with the usual level of pain (measured by a visual analogue scale) was negative (-0.26), the low ratio might be explained by reflex inhibition due to pain associated with disease.

Effect of ultrasound on mobility in osteoarthritis of the knee. A randomized clinical trial

Ultrasound increases soft tissue extensibility and may be an effective adjunct in the treatment of knee contractures secondary to connective tissue shortening. A randomized clinical trial was conducted to determine the effectiveness of ultrasound in relieving stiffness and pain in patients (age mean = 67.5 years, SD = 13.0) who had osteoarthritis (OA) and a chronic knee contracture. Subjects received 12 treatments of exercise preceded by either ultrasound (n = 34) or sham ultrasound (n = 35) and a blinded evaluation at baseline, after treatment, and 2 months after treatment. MANCOVA controlling for baseline scores showed that there were no significant differences in knee active range of motion (ROM) (goniometry) or pain (visual analogue scale) between experimental and control groups. Possible explanations for the no difference finding involve dosage issues, muscle shortening, transiency of effects, and the effects of exercise. Paired t-tests revealed that both groups significantly improved (p less than 0.05) in active ROM, pain, and gait velocity, and maintained improvement for at least 2 months. Although ultrasound may not contribute to the management of patients with chronic knee stiffness and OA, benefits of the exercise program and increased activity secondary to program participation probably influenced the overall improvement.

Self-reported functional status predicts change in level of care in independent living residents of a continuing care retirement community

OBJECTIVE

To test the hypothesis that self-reported functional status predicts change in level of care from independent to dependent in residents of a continuing care retirement community (CCRC).

DESIGN

Two-year longitudinal descriptive study of change in level of care and survival.

SUBJECTS

One hundred fifty-two residents in the independent-living unit of a non-profit CCRC. Mean age at initial evaluation was 82.3 years, SD 6.2.

MEASUREMENT

Predictor variables assessed at baseline were age, sex, physician estimate of functionally significant disease, self-reported functional status, and performance-based hand function. Criterion variables collected at 2-year follow-up were level of care (independent/dependent) and survival (alive/dead).

MAIN RESULTS

Self-reported functional status (P less than 0.01) and age (P less than 0.05) were significant predictors of change in level of care in a logistic regression analysis containing all predictor variables. No variable predicted survival.

CONCLUSIONS

Self-reported functional status may help to predict dependency in older adults in good health who have few markers of dependency risk.

Self report and performance-based hand function tests as correlates of dependency in the elderly

Preventing or minimizing functional dependency in older adults rests, in part, upon the ability to predict who is at risk. The purpose of this study was to compare the ability of five tests of hand function to discriminate the degree of dependency in older adults. Seven hundred sixty four subjects were assessed for hand function on performance-based (Williams Test of Hand Function, a test of Williams Board items only, Jebsen Test of Hand Function, grip strength), and self-reported (Dexterity Scale of the Geriatrics-Arthritis Impact Measurement Scale (GERI-AIMS] measures of hand function, and self-reported multidimensional functional status (GERI-AIMS). A trichotomous variable representing a continuum of dependency based upon living site (independent living, home-bound, institutional) was used as the measure of dependency. Sixty-two cases were dropped for incomplete data. Discriminant function analyses of the 702 subjects (age X = 76.78 years, SD = 8.79) showed that basic demographic variables explain 40.8% of the variance in dependency; all hand function tests significantly correlated with dependency; the Williams Board correlated best (additional 12.5% variance explained). However, a multidimensional functional status measure explains substantially more variance in dependency (16.9%) after controlling for demographic variables and performance on the Williams Board. This comparison of methods and tests available for measuring hand function was made to provide criteria for selecting an instrument for a given setting.