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1.
Crit Rev Oncol Hematol ; 180: 103846, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36257535

ABSTRACT

INTRODUCTION: Gastric cancer with peritoneal metastases (GCPM) carries a poor prognosis. Pressurised Intraperitoneal Aerosolised Chemotherapy (PIPAC) offers pharmacokinetic advantages over intravenous therapy, resulting in higher chemotherapy concentrations in peritoneal deposits, and potentially reduced systemic absorption/toxicity. This review evaluates efficacy, tolerability and impact on quality of life (QOL) of PIPAC for GCPM. METHODS: Following registration with PROSPERO (CRD42021281500), MEDLINE, EMBASE and The Cochrane Library were searched for PIPAC in patients with peritoneal metastases, in accordance with PRISMA standards RESULTS: Across 18 included reports representing 751 patients with GCPM (4 prospective, 11 retrospective, 3 abstracts, no phase III studies), median overall survival (mOS) was 8 - 19.1 months, 1-year OS 49.8-77.9%, complete response (PRGS1) 0-35% and partial response (PRGS2/3) 0-83.3%. Grade 3 and 4 toxicity was 0.7-25% and 0-4.1% respectively. Three studies assessing QOL reported no significant difference. CONCLUSION: PIPAC may offer promising survival benefits, toxicity, and QOL for GCPM.


Subject(s)
Peritoneal Neoplasms , Stomach Neoplasms , Humans , Peritoneal Neoplasms/drug therapy , Peritoneal Neoplasms/secondary , Stomach Neoplasms/drug therapy , Stomach Neoplasms/pathology , Quality of Life , Retrospective Studies , Prospective Studies , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Aerosols/therapeutic use , United Kingdom
2.
Geophys Res Lett ; 49(9): e2021GL096986, 2022 May 16.
Article in English | MEDLINE | ID: mdl-35864893

ABSTRACT

We report observations of reconnection exhausts in the Heliospheric Current Sheet (HCS) during Parker Solar Probe Encounters 08 and 07, at 16 R s and 20 R s , respectively. Heliospheric current sheet (HCS) reconnection accelerated protons to almost twice the solar wind speed and increased the proton core energy by a factor of ∼3, due to the Alfvén speed being comparable to the solar wind flow speed at these near-Sun distances. Furthermore, protons were energized to super-thermal energies. During E08, energized protons were found to have leaked out of the exhaust along separatrix field lines, appearing as field-aligned energetic proton beams in a broad region outside the HCS. Concurrent dropouts of strahl electrons, indicating disconnection from the Sun, provide further evidence for the HCS being the source of the beams. Around the HCS in E07, there were also proton beams but without electron strahl dropouts, indicating that their origin was not the local HCS reconnection exhaust.

3.
Phys Rev Lett ; 127(25): 255101, 2021 Dec 17.
Article in English | MEDLINE | ID: mdl-35029449

ABSTRACT

The high temperatures and strong magnetic fields of the solar corona form streams of solar wind that expand through the Solar System into interstellar space. At 09:33 UT on 28 April 2021 Parker Solar Probe entered the magnetized atmosphere of the Sun 13 million km above the photosphere, crossing below the Alfvén critical surface for five hours into plasma in casual contact with the Sun with an Alfvén Mach number of 0.79 and magnetic pressure dominating both ion and electron pressure. The spectrum of turbulence below the Alfvén critical surface is reported. Magnetic mapping suggests the region was a steady flow emerging on rapidly expanding coronal magnetic field lines lying above a pseudostreamer. The sub-Alfvénic nature of the flow may be due to suppressed magnetic reconnection at the base of the pseudostreamer, as evidenced by unusually low densities in this region and the magnetic mapping.

4.
Geophys Res Lett ; 47(20): e2020GL090115, 2020 Oct 28.
Article in English | MEDLINE | ID: mdl-33380758

ABSTRACT

The solar wind is slowed, deflected, and heated as it encounters Venus's induced magnetosphere. The importance of kinetic plasma processes to these interactions has not been examined in detail, due to a lack of constraining observations. In this study, kinetic-scale electric field structures are identified in the Venusian magnetosheath, including plasma double layers. The double layers may be driven by currents or mixing of inhomogeneous plasmas near the edge of the magnetosheath. Estimated double-layer spatial scales are consistent with those reported at Earth. Estimated potential drops are similar to electron temperature gradients across the bow shock. Many double layers are found in few high cadence data captures, suggesting that their amplitudes are high relative to other magnetosheath plasma waves. These are the first direct observations of plasma double layers beyond near-Earth space, supporting the idea that kinetic plasma processes are active in many space plasma environments.

5.
Nature ; 576(7786): 223-227, 2019 12.
Article in English | MEDLINE | ID: mdl-31802005

ABSTRACT

NASA's Parker Solar Probe mission1 recently plunged through the inner heliosphere of the Sun to its perihelia, about 24 million kilometres from the Sun. Previous studies farther from the Sun (performed mostly at a distance of 1 astronomical unit) indicate that solar energetic particles are accelerated from a few kiloelectronvolts up to near-relativistic energies via at least two processes: 'impulsive' events, which are usually associated with magnetic reconnection in solar flares and are typically enriched in electrons, helium-3 and heavier ions2, and 'gradual' events3,4, which are typically associated with large coronal-mass-ejection-driven shocks and compressions moving through the corona and inner solar wind and are the dominant source of protons with energies between 1 and 10 megaelectronvolts. However, some events show aspects of both processes and the electron-proton ratio is not bimodally distributed, as would be expected if there were only two possible processes5. These processes have been very difficult to resolve from prior observations, owing to the various transport effects that affect the energetic particle population en route to more distant spacecraft6. Here we report observations of the near-Sun energetic particle radiation environment over the first two orbits of the probe. We find a variety of energetic particle events accelerated both locally and remotely including by corotating interaction regions, impulsive events driven by acceleration near the Sun, and an event related to a coronal mass ejection. We provide direct observations of the energetic particle radiation environment in the region just above the corona of the Sun and directly explore the physics of particle acceleration and transport.

6.
Nature ; 576(7786): 228-231, 2019 12.
Article in English | MEDLINE | ID: mdl-31802006

ABSTRACT

The prediction of a supersonic solar wind1 was first confirmed by spacecraft near Earth2,3 and later by spacecraft at heliocentric distances as small as 62 solar radii4. These missions showed that plasma accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy5-7. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams8. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii9-11, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second-considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age12-14.

7.
Nature ; 576(7786): 237-242, 2019 12.
Article in English | MEDLINE | ID: mdl-31802007

ABSTRACT

During the solar minimum, when the Sun is at its least active, the solar wind1,2 is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind3 of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain4; theories and observations suggest that they may originate at the tips of helmet streamers5,6, from interchange reconnection near coronal hole boundaries7,8, or within coronal holes with highly diverging magnetic fields9,10. The heating mechanism required to drive the solar wind is also unresolved, although candidate mechanisms include Alfvén-wave turbulence11,12, heating by reconnection in nanoflares13, ion cyclotron wave heating14 and acceleration by thermal gradients1. At a distance of one astronomical unit, the wind is mixed and evolved, and therefore much of the diagnostic structure of these sources and processes has been lost. Here we present observations from the Parker Solar Probe15 at 36 to 54 solar radii that show evidence of slow Alfvénic solar wind emerging from a small equatorial coronal hole. The measured magnetic field exhibits patches of large, intermittent reversals that are associated with jets of plasma and enhanced Poynting flux and that are interspersed in a smoother and less turbulent flow with a near-radial magnetic field. Furthermore, plasma-wave measurements suggest the existence of electron and ion velocity-space micro-instabilities10,16 that are associated with plasma heating and thermalization processes. Our measurements suggest that there is an impulsive mechanism associated with solar-wind energization and that micro-instabilities play a part in heating, and we provide evidence that low-latitude coronal holes are a key source of the slow solar wind.

8.
Semin Arthritis Rheum ; 49(2): 229-235, 2019 10.
Article in English | MEDLINE | ID: mdl-30777365

ABSTRACT

OBJECTIVE: Although post-traumatic stress disorder (PTSD) is identified as a risk factor in the development of rheumatoid arthritis (RA), associations of PTSD with disease progression are less clear. To explore whether PTSD might influence disease-related measures of systemic inflammation in RA, we compared serum cytokine/chemokine (cytokine) concentrations in RA patients with and without PTSD. METHODS: Participants were U.S. Veterans with RA and were categorized as having PTSD, other forms of depression/anxiety, or neither based on administrative diagnostic codes. Multiplex cytokines were measured using banked serum. Associations of PTSD with cytokine parameters (including a weighted cytokine score) were assessed using multivariable regression, stratified by anti-CCP status and adjusted for age, sex, race, and smoking status. RESULTS: Among 1,460 RA subjects with mean (SD) age of 64 (11) years and disease duration of 11 (11) years, 91% were male, 77% anti-CCP positive, and 80% ever smokers. Of these, 11.6% had PTSD, 23.7% other depression/anxiety, and 64.7% had neither. PTSD, but not depression/anxiety, was associated with a higher cytokine score and number of high-concentration analytes in adjusted models, though this was limited to anti-CCP positive subjects. PTSD was associated with heightened expression of several individual cytokines including IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, IL-12, IL-17, IFN-γ, GM-CSF, MCP-1, and TNF-α. CONCLUSION: Anti-CCP positive RA patients with PTSD have higher serum cytokine concentrations than those without PTSD, demonstrating that systemic inflammation characteristic of RA is heightened in the context of this relatively common psychiatric comorbidity.


Subject(s)
Arthritis, Rheumatoid/complications , Chemokines/blood , Cytokines/blood , Stress Disorders, Post-Traumatic/complications , Veterans , Aged , Arthritis, Rheumatoid/blood , Female , Humans , Male , Middle Aged , Stress Disorders, Post-Traumatic/blood
9.
Phytopathology ; 107(8): 950-962, 2017 08.
Article in English | MEDLINE | ID: mdl-28398875

ABSTRACT

The emergence of widely virulent pathotypes (e.g., TTKSK in the Ug99 race group) of the stem rust pathogen (Puccinia graminis f. sp. tritici) in Africa threatens wheat production on a global scale. Although intensive research efforts have been advanced to address this threat in wheat, few studies have been conducted on barley, even though pathotypes such as TTKSK are known to attack the crop. The main objectives of this study were to assess the vulnerability of barley to pathotype TTKSK and identify possible sources of resistance. From seedling evaluations of more than 1,924 diverse cultivated barley accessions to pathotype TTKSK, more than 95% (1,844) were found susceptible. A similar high frequency (910 of 934 = 97.4%) of susceptibility was found for the wild progenitor (Hordeum vulgare subsp. spontaneum) of cultivated barley. Additionally, 55 barley lines with characterized or putative introgressions from various wild Hordeum spp. were also tested against pathotype TTKSK but none was found resistant. In total, more than 96% of the 2,913 Hordeum accessions tested were susceptible as seedlings, indicating the extreme vulnerability of the crop to the African pathotypes of P. graminis f. sp. tritici. In total, 32 (1.7% of accessions evaluated) and 13 (1.4%) cultivated and wild barley accessions, respectively, exhibited consistently highly resistant to moderately resistant reactions across all experiments. Molecular assays were conducted on these resistant accessions to determine whether they carried rpg4/Rpg5, the only gene complex known to be highly effective against pathotype TTKSK in barley. Twelve of the 32 (37.5%) resistant cultivated accessions and 11 of the 13 (84.6%) resistant wild barley accessions tested positive for a functional Rpg5 gene, highlighting the narrow genetic base of resistance in Hordeum spp. Other resistant accessions lacking the rpg4/Rpg5 complex were discovered in the evaluated germplasm and may possess useful resistance genes. Combining rpg4/Rpg5 with resistance genes from these other sources should provide more durable resistance against the array of different virulence types in the Ug99 race group.


Subject(s)
Basidiomycota/physiology , Hordeum/metabolism , Hordeum/microbiology , Plant Diseases/microbiology , Disease Resistance , Gene Expression Regulation, Plant/physiology , Hordeum/genetics , Plant Proteins/genetics , Plant Proteins/metabolism
10.
Oxid Med Cell Longev ; 2016: 5296271, 2016.
Article in English | MEDLINE | ID: mdl-26770655

ABSTRACT

Herbicides containing paraquat may contribute to the pathogenesis of neurodegenerative disorders such as Parkinson's disease. Paraquat induces reactive oxygen species-mediated apoptosis in neurons, which is a primary mechanism behind its toxicity. We sought to test the effectiveness of a commercially available polyphenol-rich Aronia melanocarpa (aronia berry) concentrate in the amelioration of paraquat-induced neurotoxicity. Considering the abundance of antioxidants in aronia berries, we hypothesized that aronia berry concentrate attenuates the paraquat-induced increase in reactive oxygen species and protects against paraquat-mediated neuronal cell death. Using a neuronal cell culture model, we observed that low doses of aronia berry concentrate protected against paraquat-mediated neurotoxicity. Additionally, low doses of the concentrate attenuated the paraquat-induced increase in superoxide, hydrogen peroxide, and oxidized glutathione levels. Interestingly, high doses of aronia berry concentrate increased neuronal superoxide levels independent of paraquat, while at the same time decreasing hydrogen peroxide. Moreover, high-dose aronia berry concentrate potentiated paraquat-induced superoxide production and neuronal cell death. In summary, aronia berry concentrate at low doses restores the homeostatic redox environment of neurons treated with paraquat, while high doses exacerbate the imbalance leading to further cell death. Our findings support that moderate levels of aronia berry concentrate may prevent reactive oxygen species-mediated neurotoxicity.


Subject(s)
Neurotoxins/toxicity , Paraquat/toxicity , Photinia/chemistry , Plant Extracts/pharmacology , Antioxidants/metabolism , Cell Death/drug effects , Cell Line, Tumor , Dose-Response Relationship, Drug , Glutathione/metabolism , Humans , Hydrogen Peroxide/metabolism , Neurons/drug effects , Neurons/metabolism , Neurons/pathology , Oxidants/toxicity , Oxidation-Reduction/drug effects , Superoxides/metabolism
11.
J Matern Fetal Neonatal Med ; 25(4): 395-402, 2012 Apr.
Article in English | MEDLINE | ID: mdl-21627552

ABSTRACT

OBJECTIVE: To describe the patterns of cesarean section (CS) and vaginal delivery by type of birth defect and determine whether prenatal diagnosis predicts a higher or lower likelihood of CS for selected defect categories. METHODS: Data from a large population-based registry were analyzed to determine percentages of vaginal versus CS delivery for each of 49 categories of birth defects. Odds ratios and statistical significance were computed to determine if a record of prenatal diagnosis (PND) predicted delivery mode. Cases were liveborn children with any of these defects born in Texas between 1997 and 2005. RESULTS: Forty-three percent of infants in the study were delivered by CS, with a range of 25.3% (aniridia) to 62.4% (spina bifida). A record of prenatal diagnosis of the primary assigned birth defect was found in 43.0% of all records but varied substantially by defect category. PND significantly predicted higher CS percentages for spina bifida without anencephaly, encephalocele, hydrocephaly, transposition of the great vessels, ventricular septal defect, pulmonary valve atresia/stenosis, craniosynostosis, diaphragmatic hernia, gastroschisis, and trisomy 21. Vaginal delivery was predicted by PND of anencephaly, agenesis, aplasia, or hypoplasia of the lung, renal agenesis or dysgenesis, and trisomy 18. CONCLUSION: Texas children with birth defects are more likely to have been delivered by CS than the population in general. For several types of defects, prenatal diagnosis is predictive of higher odds of CS; for others, especially fatal defects, PND predicts lower CS likelihood.


Subject(s)
Cesarean Section/statistics & numerical data , Congenital Abnormalities/diagnosis , Congenital Abnormalities/epidemiology , Prenatal Diagnosis/statistics & numerical data , Registries/statistics & numerical data , Cohort Studies , Delivery, Obstetric/statistics & numerical data , Female , Gestational Age , Humans , Infant, Newborn , Population , Pregnancy , Sample Size , Texas/epidemiology
12.
Gynecol Oncol ; 122(3): 612-7, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21570710

ABSTRACT

OBJECTIVE: To determine the prognostic significance of the 2002 revisions of the American Joint Committee on Cancer (AJCC) Staging System for cutaneous melanoma in melanoma of the vulva and review the current surgical utilized for treatment of this neoplasm. METHODS: Demographic, surgical and outcomes data were obtained from the records of vulvar melanoma patients treated from 1990 to 2006 at five academic medical centers. The 2002 modifications of the AJCC staging system for cutaneous melanoma, Breslow thickness and Clark level, were applied to all subjects. Kaplan-Meier Modeling and Linear Regression analysis were utilized for data analysis. Statistics were performed with SAS v 9.1. RESULTS: Seventy-seven patients were identified with a median age of 62 years. 73% had Stage I/II disease. Surgical radicality did not impact recurrence rates or survival. Breslow thickness was associated with recurrence (p=0.002) but not survival. Only the 2002 modified AJCC staging criteria were predictive of overall survival (p=0.006) in patients with malignant melanoma of the vulva. CONCLUSIONS: In the largest multi-site series of vulvar melanoma, the AJCC-2002 staging system for cutaneous malignant melanoma appears to be applicable to primary vulvar melanoma. Moreover, surgical radicality was associated with significant morbidity but not with improvement in survival. Utilization of standard operative staging and resection principles in cutaneous melanoma should be used for all vulvar melanoma patients. Moreover, these patients should also be considered for enrollment in cutaneous melanoma clinical trials.


Subject(s)
Melanoma/pathology , Skin Neoplasms/pathology , Vulvar Neoplasms/pathology , Adult , Aged , Aged, 80 and over , Female , Humans , Lymph Node Excision , Lymph Nodes/pathology , Lymph Nodes/surgery , Lymphatic Metastasis , Melanoma/surgery , Middle Aged , Neoplasm Staging , Sentinel Lymph Node Biopsy , Skin Neoplasms/surgery , Treatment Outcome , Vulvar Neoplasms/surgery
13.
Dev Neurosci ; 32(4): 313-20, 2010.
Article in English | MEDLINE | ID: mdl-20938157

ABSTRACT

The myelin-associated protein Nogo-A is a well-known inhibitor of axonal regeneration and compensatory plasticity, yet functions of neuronal Nogo-A are not as clear. The present study examined the effects of decreased levels of neuronal Nogo-A on dendritic spines of developing neocortical neurons. Decreased Nogo-A levels in these neurons resulted in lowered spine density and an increase in filopodial type protrusions. These results suggest a role for neuronal Nogo-A in maintaining a spine phenotype in neocortical pyramidal cells.


Subject(s)
Dendritic Spines/ultrastructure , Myelin Proteins/metabolism , Neocortex/pathology , Pyramidal Cells/ultrastructure , Animals , Blotting, Western , Cell Line , Dendritic Spines/metabolism , Gene Knockdown Techniques , Humans , Image Processing, Computer-Assisted , Male , Microscopy, Confocal , Myelin Proteins/genetics , Neocortex/metabolism , Nogo Proteins , Pyramidal Cells/metabolism , RNA Interference , Rats
14.
Tydskr Stud Ekon Ekon ; 34(3): 69-85, 2010 Jan 01.
Article in English | MEDLINE | ID: mdl-21915159

ABSTRACT

This paper investigates the association between mental health and socioeconomic status and assesses the extent to which the correlates of depression change over the life cycle. Mean depression scores for South Africans are markedly higher than those found in other countries. There are large differences in depression between population groups. For both men and women, sixty percent of the gap between Africans and whites can be explained by their socioeconomic status. Household expenditure per member and the number of assets owned by the household are significant negative correlates of depression, as is educational attainment. Reporting that one is on the lowest rung of the socioeconomic status ladder, or that children in the household are often hungry, is associated with reporting more depressive symptoms. Adults report more symptoms of depression and anxiety at older ages, with the most dramatic increase occurring between young adulthood and middle adulthood. For the African sub-sample, this can be explained in part by prime-age and older adults being more troubled by poverty.

16.
Vet Rec ; 164(20): 616-8, 2009 May 16.
Article in English | MEDLINE | ID: mdl-19448253

ABSTRACT

The aim of this study was to identify factors that contribute significantly to the bacterial contamination of peripheral intravenous catheters in dogs and cats. Between January and June 2005, intravenous catheters were removed from 84 dogs and 15 cats at the Queen Mother Hospital for Animals, Royal Veterinary College. None of the factors under consideration was significantly associated with bacterial contamination, but 42.9 per cent of the animals with clinical signs consistent with a peripheral catheter-related infection, 34.8 per cent of the animals in which blood had been collected from the catheter immediately after its insertion, and 21.1 per cent of the animals in which a T-connector rather than a Y-connector had been used had contaminated cannulae, compared with 19.0 per cent, 19.7 per cent and 8.3 per cent, respectively, of the animals that did not have signs of such an infection, from which blood was not taken immediately, and that had a Y-connector rather than a T-connector. Binary logistic regression showed that the animals with clinical signs of a catheter-related infection were 10 times more likely to have a contaminated catheter (odds ratio [OR] 10.9, 95 per cent confidence interval [CI] 0.89 to 134) and the animals fitted with Y-connectors rather than T-connectors were 10 times less likely to have a contaminated catheter (OR 0.10, 95 per cent CI 0.008 to 1.25).


Subject(s)
Cat Diseases/microbiology , Catheterization, Peripheral/veterinary , Catheters, Indwelling/microbiology , Cross Infection/veterinary , Dog Diseases/microbiology , Animals , Catheterization, Peripheral/adverse effects , Catheterization, Peripheral/methods , Cats , Cross Infection/microbiology , Dogs , Equipment Contamination , Female , Infusions, Intravenous/adverse effects , Infusions, Intravenous/methods , Infusions, Intravenous/veterinary , Logistic Models , Male , Risk Factors , United Kingdom
17.
J Evol Biol ; 20(4): 1396-405, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17584234

ABSTRACT

Variation in population sex ratio can be influenced by natural selection on alternate sex phenotypes as well as nonselective mechanisms, such as genetic drift and founder effects. If natural selection contributes to variation in population sex ratio, then sex ratio should covary with resource availability or herbivory. With nonselective mechanisms, sex ratio should covary with population size. We estimated sex ratio, resource availability, herbivory and size of 53 populations of gynodioecious Lobelia siphilitica. Females were more common in populations with higher annual temperatures, lower soil moisture and lower predation on female fruits, consistent with sex-specific selection. Females were also more common in small populations, consistent with drift, inbreeding or founder effects. However, small populations occurred in areas with higher temperatures than large populations, suggesting that female frequencies in small populations could be caused by sex-specific selection. Both selective and nonselective mechanisms likely affect sex ratio variation in this gynodioecious species.


Subject(s)
Lobelia/genetics , Genetics, Population , Phenotype , Population Density , Selection, Genetic
18.
Med Vet Entomol ; 16(2): 186-92, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12109713

ABSTRACT

Enzyme-linked immunosorbent assay (ELISA) was used to investigate the antibody responses of control sheep, and sheep naturally exposed to Ixodes ricinus Linné (Acari: Ixodidae) ticks, to salivary gland extract (SGE) proteins of partially fed, adult I. ricinus. Comparisons between responses of control sheep and naturally infested sheep by Western blot analysis suggested that variations in IgG responses of I. ricinus-exposed sheep were mostly associated with specific responses to I. ricinus SGE antigens. Sheep IgG responses were positively related to the numbers of adult ticks feeding per sheep at the time samples were collected, were greater during the spring than the autumn periods of I. ricinus activity and were inversely related to sheep resistance to ticks measured by the weights of nymphal I. ricinus that engorged on the sheep. These findings suggest that sheep lose their resistance to ticks due to polarization of a Th1 type response to some tick antigens towards a Th2 type response when sheep are exposed to high, natural tick infestations, or to seasonal conditions of relative nutritional stress. Potential consequences for the epidemiology of tick-borne diseases are discussed.


Subject(s)
Immunoglobulin G/biosynthesis , Ixodes/immunology , Sheep Diseases/immunology , Tick Infestations/veterinary , Animals , Antigens/analysis , Blotting, Western/veterinary , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Host-Parasite Interactions , Male , Salivary Glands/immunology , Seasons , Sheep , Sheep Diseases/parasitology , T-Lymphocytes, Helper-Inducer , Tick Infestations/immunology , Tick-Borne Diseases/immunology , Tick-Borne Diseases/parasitology , Tick-Borne Diseases/prevention & control , Tissue Extracts/immunology
19.
J Health Econ ; 20(3): 301-28, 2001 May.
Article in English | MEDLINE | ID: mdl-11373833

ABSTRACT

We estimate the impact of family structure on investments made in children's health, using data from the 1988 National Health Interview Survey Child Health Supplement. Controlling for household size, income and characteristics, we find that children living with step-mothers are significantly less likely to have routine doctor and dentist visits, or to have a place for usual medical care, or for sick care. Who invests in children's health? It appears these investments are made, largely, by a child's mother, and that step-mothers are not substitutes for birth-mothers in this domain.


Subject(s)
Child Health Services/statistics & numerical data , Child Welfare/statistics & numerical data , Family Characteristics , Family Health , Mother-Child Relations , Patient Acceptance of Health Care/psychology , Adolescent , Child , Child, Preschool , Decision Making , Father-Child Relations , Female , Health Care Surveys , Humans , Infant , Male , Maternal Deprivation , Parenting/psychology , Preventive Health Services/statistics & numerical data , Socioeconomic Factors , United States
20.
Compr Ther ; 27(1): 65-71, 2001.
Article in English | MEDLINE | ID: mdl-11280858

ABSTRACT

Menstrual cycle-related exacerbation of common medical conditions such as migraine, epilepsy, asthma, irritable bowel syndrome, and diabetes, is a well-recognized phenomenon. Accurate documentation of symptoms on a menstrual calendar allows identification of women with cyclic alterations in disease activity.


Subject(s)
Menstrual Cycle , Migraine Disorders/etiology , Premenstrual Syndrome/etiology , Asthma/etiology , Epilepsy/etiology , Estrogens/blood , Estrogens/therapeutic use , Female , Gonadotropin-Releasing Hormone/agonists , Humans , Migraine Disorders/drug therapy , Premenstrual Syndrome/physiopathology
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