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1.
Ann Surg ; 276(6): e758-e763, 2022 12 01.
Article in English | MEDLINE | ID: mdl-33351483

ABSTRACT

OBJECTIVE: To determine the incremental yield of standardized addition of chest CT to abdominal CT to detect COVID-19 in patients presenting with primarily acute gastrointestinal symptoms requiring abdominal imaging. Summary Background Data: Around 20% of patients with COVID-19 present with gastrointestinal symptoms. COVID-19 might be neglected in these patients, as the focus could be on finding abdominal pathology. During the COVID-19 pandemic, several centers have routinely added chest CT to abdominal CT to detect possible COVID-19 in patients presenting with gastrointestinal symptoms. However, the incremental yield of this strategy is unknown. METHODS: This multicenter study in 6 Dutch centers included consecutive adult patients presenting with acute nontraumatic gastrointestinal symptoms, who underwent standardized combined abdominal and chest CT between March 15, 2020 and April 30, 2020. All CT scans were read for signs of COVID-19 related pulmonary sequelae using the СО-RADS score. The primary outcome was the yield of high COVID-19 suspicion (СО-RADS 4-5) based on chest CT. RESULTS: A total of 392 patients were included. Radiologic suspicion for COVID-19 (СО-RADS 4-5) was present in 17 (4.3%) patients, eleven of which were diagnosed with COVID-19. Only 5 patients with СО-RADS 4-5 presented without any respiratory symptoms and were diagnosed with COVID-19. No relation with community prevalence could be detected. CONCLUSION: The yield of adding chest CT to abdominal CT to detect COVID-19 in patients presenting with acute gastrointestinal symptoms is extremely low with an additional detection rate of around 1%.


Subject(s)
COVID-19 , Gastrointestinal Diseases , Adult , Humans , COVID-19/diagnostic imaging , Pandemics , Thorax/diagnostic imaging , Tomography, X-Ray Computed , Gastrointestinal Diseases/diagnostic imaging
2.
Transbound Emerg Dis ; 65(3): 817-832, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29423949

ABSTRACT

Equine herpesvirus 1 (EHV-1) causes respiratory disease, abortion, neonatal death and neurological disease in equines and is endemic in most countries. The viral factors that influence EHV-1 disease severity are poorly understood, and this has hampered vaccine development. However, the N752D substitution in the viral DNA polymerase catalytic subunit has been shown statistically to be associated with neurological disease. This has given rise to the term "neuropathic strain," even though strains lacking the polymorphism have been recovered from cases of neurological disease. To broaden understanding of EHV-1 diversity in the field, 78 EHV-1 strains isolated over a period of 35 years were sequenced. The great majority of isolates originated from the United Kingdom and included in the collection were low passage isolates from respiratory, abortigenic and neurological outbreaks. Phylogenetic analysis of regions spanning 80% of the genome showed that up to 13 viral clades have been circulating in the United Kingdom and that most of these are continuing to circulate. Abortion isolates grouped into nine clades, and neurological isolates grouped into five. Most neurological isolates had the N752D substitution, whereas most abortion isolates did not, although three of the neurological isolates from linked outbreaks had a different polymorphism. Finally, bioinformatic analysis suggested that recombination has occurred between EHV-1 clades, between EHV-1 and equine herpesvirus 4, and between EHV-1 and equine herpesvirus 8.


Subject(s)
Abortion, Veterinary/virology , Brain Diseases/veterinary , Genetic Variation , Herpesviridae Infections/veterinary , Herpesvirus 1, Equid/genetics , Horse Diseases/virology , Respiration Disorders/veterinary , Animals , Base Sequence , Brain Diseases/virology , DNA, Viral/genetics , DNA-Directed DNA Polymerase/genetics , Disease Outbreaks/veterinary , Equidae , Female , Herpesviridae Infections/epidemiology , Herpesviridae Infections/virology , Herpesvirus 1, Equid/isolation & purification , Horse Diseases/epidemiology , Horses , Phylogeny , Pregnancy , Respiration Disorders/virology , United Kingdom
3.
Dalton Trans ; 44(21): 9756-65, 2015 Jun 07.
Article in English | MEDLINE | ID: mdl-25928403

ABSTRACT

Three dimethyltindiamides containing chelating diamide ligands were synthesised from the reaction of the dilithiated diamine and Me2SnCl2; [SnMe2(L1)] 1 (L1 = κ(2)-N(Dipp)C2H4N(Dipp)), [SnMe2(L2)] 2 (L2 = κ(2)-N(Dipp)C3H6N(Dipp)) and [SnMe2(L3)] 3 (L3 = κ(2)-N(Dipp)SiPh2N(Dipp)), Dipp = 2,6-(i)Pr2C6H3. Reaction of (L2)H2 with SnCl4 and NEt3 led to the formation of the diamidotin dichloride [SnCl2(L2)] 4 whereas reaction of (L1)H2 with SnCl4 and NEt3, or [Sn(L1)] with SnCl4, led to the exclusive formation of the amidotin trichloride [SnCl3{κ(2)-DippN(H)C2H4N(Dipp)}] 5. Reactions of [Sn(L1)] with sulfur and selenium formed [{Sn(L1)(µ-E)}2] (E = S 10 and Se )11. MeI reacted with N-heterocyclic stannylenes to generate the Sn(iv) addition products [Sn(Me)I(L1)] 12, [Sn(Me)I(L2)] 13, [Sn(Me)I(L3)] 14 and [Sn(Me)I(L4)] 15 (L4 = κ(3)-N(Dipp)C2H4OC2H4N(Dipp)), and subsequent reaction with AgOTf (OTf = OSO2CF3) generated the corresponding Sn(iv) triflates [Sn(Me)OTf(L1)] 16, [Sn(Me)OTf(L2)] 17 and [Sn(Me)OTf(L4)] 19 with [Sn(Me)OTf(L3)] 18 formed only as a mixture with unidentified by-products. All of the compounds were characterised by single crystal X-ray diffraction.

4.
Eur J Clin Nutr ; 69(5): 539-45, 2015 May.
Article in English | MEDLINE | ID: mdl-25604774

ABSTRACT

Health-care systems are currently facing tremendous budget constraints resulting in growing pressure on decision makers and health-care providers to obtain the maximum possible health benefits of the resources available. Choices have to be made, and health economics can help in allocating limited health-care resources among unlimited wants and needs. Attempts to achieve cost reductions often focus on severe pathologies and chronic diseases as they commonly represent high health-care expenditures. In this context, awareness of the considerable financial burden caused by disease-related malnutrition (DRM) is lacking. Possibilities of reducing costs by optimising the management of DRM through medical nutrition will mostly not even be taken into account. During a European expert meeting, the total evaluation of medical nutrition was viewed and discussed. The aim of this meeting was to gain an experts' outline of the key issues relating to the health economic assessment of the use of medical nutrition. This article provides a summary of the observations per discussed item and describes the next steps suggested.


Subject(s)
Expert Testimony/economics , Health Resources/economics , Health Services Needs and Demand/economics , Malnutrition/economics , Nutrition Policy/economics , Cost-Benefit Analysis , Europe , Humans , Malnutrition/therapy
5.
Science ; 346(6212): 996-1000, 2014 Nov 21.
Article in English | MEDLINE | ID: mdl-25414313

ABSTRACT

We introduce the antibody landscape, a method for the quantitative analysis of antibody-mediated immunity to antigenically variable pathogens, achieved by accounting for antigenic variation among pathogen strains. We generated antibody landscapes to study immune profiles covering 43 years of influenza A/H3N2 virus evolution for 69 individuals monitored for infection over 6 years and for 225 individuals pre- and postvaccination. Upon infection and vaccination, titers increased broadly, including previously encountered viruses far beyond the extent of cross-reactivity observed after a primary infection. We explored implications for vaccination and found that the use of an antigenically advanced virus had the dual benefit of inducing antibodies against both advanced and previous antigenic clusters. These results indicate that preemptive vaccine updates may improve influenza vaccine efficacy in previously exposed individuals.


Subject(s)
Antibodies, Viral/immunology , Influenza A Virus, H3N2 Subtype/immunology , Influenza Vaccines/immunology , Influenza, Human/immunology , Vaccination , Antibodies, Viral/blood , Antigenic Variation/genetics , Antigenic Variation/immunology , Evolution, Molecular , Humans , Influenza A Virus, H3N2 Subtype/genetics , Influenza, Human/blood , Influenza, Human/prevention & control
6.
J Gen Virol ; 95(Pt 2): 384-392, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24187014

ABSTRACT

The current measures to control foot-and-mouth disease (FMD) include vaccination, movement control and slaughter of infected or susceptible animals. One of the difficulties in controlling FMD by vaccination arises due to the substantial diversity found among the seven serotypes of FMD virus (FMDV) and the strains within these serotypes. Therefore, vaccination using a single vaccine strain may not fully cross-protect against all strains within that serotype, and therefore selection of appropriate vaccines requires serological comparison of the field virus and potential vaccine viruses using relationship coefficients (r1 values). Limitations of this approach are that antigenic relationships among field viruses are not addressed, as comparisons are only with potential vaccine virus. Furthermore, inherent variation among vaccine sera may impair reproducibility of one-way relationship scores. Here, we used antigenic cartography to quantify and visualize the antigenic relationships among FMD serotype A viruses, aiming to improve the understanding of FMDV antigenic evolution and the scope and reliability of vaccine matching. Our results suggest that predicting antigenic difference using genetic sequence alone or by geographical location is not currently reliable. We found co-circulating lineages in one region that were genetically similar but antigenically distinct. Nevertheless, by comparing antigenic distances measured from the antigenic maps with the full capsid (P1) sequence, we identified a specific amino acid substitution associated with an antigenic mismatch among field viruses and a commonly used prototype vaccine strain, A22/IRQ/24/64.


Subject(s)
Antigenic Variation , Capsid Proteins/genetics , Capsid Proteins/immunology , Foot-and-Mouth Disease Virus/genetics , Foot-and-Mouth Disease Virus/immunology , Animals , Cell Line , Molecular Sequence Data , Phylogeny , RNA, Viral/genetics , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Swine
7.
Breast Cancer Res Treat ; 131(3): 899-906, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22042372

ABSTRACT

Inhibition of the HER-2 pathway via the monoclonal antibody trastuzumab has had a major impact in treatment of HER-2 positive breast cancer, but de novo or acquired resistance may reduce its effectiveness. The known interplay between the epidermal growth factor receptor (EGFR) and HER-2 receptors and pathways creates a rationale for combined anti-EGFR and anti-HER-2 therapy in HER-2 positive metastatic breast cancer (MBC), and toxicities associated with the use of multiple chemotherapeutic agents together with biological therapies may also be reduced. We conducted a prospective, single arm, phase I/II trial to determine the efficacy and toxicity of the combination of trastuzumab with the EGFR inhibitor gefitinib and docetaxel, in patients with HER-2 positive MBC. The maximum tolerated dose (MTD) was determined in the phase I portion. The primary end point of the phase II portion was progression-free survival (PFS). Immunohistochemical analysis of biomarker expression of the PKA-related proteins cAMP response element-binding protein (CREB), phospho-CREB and DARPP-32 (dopamine and cAMP-regulated phosphoprotein of 32 kDa) plus t-DARPP (the truncated isoform of DARPP-32); PTEN; p-p70 S6K; and EGFR was conducted on tissue from metastatic sites. Nine patients were treated in the phase I portion of the study and 22 in the phase II portion. The MTD was gefitinib 250 mg on days 2-14, trastuzumab 6 mg/kg, and docetaxel 60 mg/m(2) every 21 days. For the 29 patients treated at the MTD, median PFS was 12.7 months, with complete and partial response rates of 18 and 46%, and a stable disease rate of 29%. No statistically significant correlation was found between response and expression of any biomarkers. We conclude that the combination of gefitinib, trastuzumab, and docetaxel is feasible and effective. Expression of the biomarkers examined did not predict outcome in this sample of HER-2 overexpressing metastatic breast cancer.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Receptor, ErbB-2/antagonists & inhibitors , Adult , Aged , Antibodies, Monoclonal, Humanized/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Biomarkers, Tumor/metabolism , Breast Neoplasms/mortality , Docetaxel , ErbB Receptors/antagonists & inhibitors , Female , Gefitinib , Humans , Middle Aged , Neoplasm Metastasis , Neoplasm Staging , Quinazolines/administration & dosage , Taxoids/administration & dosage , Trastuzumab , Treatment Outcome
8.
J Virol ; 85(23): 12742-9, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21937642

ABSTRACT

Equine influenza virus is a major respiratory pathogen in horses, and outbreaks of disease often lead to substantial disruption to and economic losses for equestrian industries. The hemagglutinin (HA) protein is of key importance in the control of equine influenza because HA is the primary target of the protective immune response and the main component of currently licensed influenza vaccines. However, the influenza virus HA protein changes over time, a process called antigenic drift, and vaccine strains must be updated to remain effective. Antigenic drift is assessed primarily by the hemagglutination inhibition (HI) assay. We have generated HI assay data for equine influenza A (H3N8) viruses isolated between 1968 and 2007 and have used antigenic cartography to quantify antigenic differences among the isolates. The antigenic evolution of equine influenza viruses during this period was clustered: from 1968 to 1988, all isolates formed a single antigenic cluster, which then split into two cocirculating clusters in 1989, and then a third cocirculating cluster appeared in 2003. Viruses from all three clusters were isolated in 2007. In one of the three clusters, we show evidence of antigenic drift away from the vaccine strain over time. We determined that a single amino acid substitution was likely responsible for the antigenic differences among clusters.


Subject(s)
Evolution, Molecular , Hemagglutinin Glycoproteins, Influenza Virus/immunology , Influenza A Virus, H3N8 Subtype/genetics , Influenza A Virus, H3N8 Subtype/immunology , Orthomyxoviridae Infections/virology , Amino Acid Substitution , Animals , Antigens, Viral/classification , Antigens, Viral/immunology , Blotting, Western , Cells, Cultured , Dogs , Hemagglutination Inhibition Tests , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Hemagglutinins/immunology , Hemagglutinins/metabolism , Horses , Influenza A Virus, H3N8 Subtype/isolation & purification , Kidney/cytology , Kidney/metabolism , Kidney/virology , Orthomyxoviridae Infections/genetics , Orthomyxoviridae Infections/immunology , Phylogeny , RNA, Messenger/genetics , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , Time Factors
9.
Ann Oncol ; 22(5): 1094-1101, 2011 May.
Article in English | MEDLINE | ID: mdl-21084429

ABSTRACT

BACKGROUND: Safety and efficacy of gemcitabine plus docetaxel (GD) and capecitabine plus docetaxel (CD) were compared in patients with metastatic breast cancer, where the alternate crossover monotherapy (GD→C or CD→G) was predetermined. PATIENTS AND METHODS: Patients were randomly assigned to 3-week cycles of either gemcitabine 1000 mg/m(2) on days 1 and 8 plus docetaxel 75 mg/m(2) on day 1 or capecitabine 1000 mg/m(2) twice daily on days 1-14 plus docetaxel 75 mg/m(2) day 1. Upon progression, patients received crossover monotherapy. Primary end point was time to progression (TtP). Secondary end points evaluated overall response rate (ORR), overall survival (OS), and adverse events (AEs). RESULTS: Despite over-accrual of 475 patients, the trial matured with only 324 of 385 planned TtP events due to patient discontinuations. Human epidermal growth factor receptor 2 status was not captured in this study. More CD patients (28%) discontinued due to AEs than GD patients (18.0%, P = 0.009). TtP [hazard ratio (HR) = 1.101, 95% confidence interval (CI) 0.885-1.370, P = 0.387] and OS (HR = 1.031, 95% CI 0.830-1.280, P = 0.785) were not significantly different comparing GD and CD. ORR was not statistically different (P = 0.239) comparing GD (72 of 207, 34.8%) and CD (78 of 191, 40.8%). TtP, OS, and ORR were not significantly different comparing crossover groups. GD caused greater fatigue, hepatotoxicity, neutropenia, and thrombocytopenia but not febrile neutropenia; CD caused more hand-foot syndrome, gastrointestinal toxicity, and mucositis. CONCLUSIONS: GD and CD produced similar efficacy and toxicity profiles consistent with prior clinical experience.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Breast Neoplasms/drug therapy , Adult , Aged , Aged, 80 and over , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Capecitabine , Cross-Over Studies , Deoxycytidine/administration & dosage , Deoxycytidine/analogs & derivatives , Disease-Free Survival , Docetaxel , Female , Fluorouracil/administration & dosage , Fluorouracil/analogs & derivatives , Humans , Kaplan-Meier Estimate , Middle Aged , Neoplasm Metastasis , Taxoids/administration & dosage , Gemcitabine
10.
J Virol ; 84(22): 11841-8, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20826698

ABSTRACT

All lyssaviruses cause fatal encephalitis in mammals. There is sufficient antigenic variation within the genus to cause variable vaccine efficacy, but this variation is difficult to characterize quantitatively: sequence analysis cannot yet provide detailed antigenic information, and antigenic neutralization data have been refractory to high-resolution robust interpretation. Here, we address these issues by using state-of-the-art antigenic analyses to generate a high-resolution antigenic map of a global panel of 25 lyssaviruses. We compared the calculated antigenic distances with viral glycoprotein ectodomain sequence data. Although 67% of antigenic variation was predictable from the glycoprotein amino acid sequence, there are in some cases substantial differences between genetic and antigenic distances, thus highlighting the risk of inferring antigenic relationships solely from sequence data at this time. These differences included epidemiologically important antigenic differences between vaccine strains and wild-type rabies viruses. Further, we quantitatively assessed the antigenic relationships measured by using rabbit, mouse, and human sera, validating the use of nonhuman experimental animals as a model for determining antigenic variation in humans. The use of passive immune globulin is a crucial component of rabies postexposure prophylaxis, and here we also show that it is possible to predict the reactivity of immune globulin against divergent lyssaviruses.


Subject(s)
Antigens, Viral/immunology , Lyssavirus/immunology , Rhabdoviridae Infections/virology , Viral Proteins/immunology , Amino Acid Sequence , Animals , Antibodies, Viral/immunology , Antigenic Variation , Antigens, Viral/chemistry , Antigens, Viral/genetics , Cell Line , Cricetinae , Humans , Lyssavirus/chemistry , Lyssavirus/classification , Lyssavirus/genetics , Mice , Molecular Sequence Data , Neutralization Tests , Rabbits , Rhabdoviridae Infections/immunology , Sequence Homology, Amino Acid , Viral Proteins/chemistry , Viral Proteins/genetics
11.
Proc Nutr Soc ; 69(4): 465-9, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20550749

ABSTRACT

More than 3 million individuals are estimated to be at risk of malnutrition in the UK, of whom about 93% live in the community. BAPEN's Nutrition Screening Week surveys using criteria based on the 'Malnutrition Universal Screening Tool' ('MUST') revealed that 28% of individuals on admission to hospital and 30-40% of those admitted to care homes in the previous 6 months were malnourished (medium+high risk using 'MUST'). About three quarters of hospital admissions and about a third of care home admissions came from their own homes with a malnutrition prevalence of 24% in each case. Outpatient studies using 'MUST' showed that 16-20% patients were malnourished and these were associated with more hospital admissions and longer length of stay. In sheltered housing, 10-14% of the tenants were found to be malnourished, with an overall estimated absolute prevalence of malnutrition which exceeded that in hospitals. In all cases, the majority of subjects were at high risk of malnutrition. These studies have helped establish the magnitude of the malnutrition problem in the UK and identified the need for integrated strategies between and within care settings. While hospitals provide a good opportunity to identify malnourished patients among more than 10 million patients admitted there annually and the five- to six-fold greater number attending outpatient departments, commissioners and providers of healthcare services should be aware that much of the malnutrition present in the UK originates in the community before admission to hospitals or care homes or attendance at outpatient clinics.


Subject(s)
Malnutrition/epidemiology , Hospitalization , Humans , Prevalence , United Kingdom/epidemiology
12.
Proc Nutr Soc ; 69(4): 470-6, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20550750

ABSTRACT

In 2007, the estimated cost of disease-related malnutrition in the UK was in excess of £13×109. At any point in time, only about 2% of over 3 million individuals at risk of malnutrition were in hospital, 5% in care homes and the remainder in the community (2-3% in sheltered housing). Some government statistics (England) grossly underestimated the prevalence of malnutrition on admission and discharge from hospital (1000-3000 annually between 1998 and 2008), which is less than 1% of the prevalence (about 3 million in 2007-2008) established by national surveys using criteria based on the 'Malnutrition Universal Screening Tool' ('MUST'). The incidence of malnutrition-related deaths in hospitals, according to government statistics (242 deaths in England in 2007), was also <1% of an independent estimate, which was as high as 100 000/year. Recent healthcare policies have reduced the number of hospital and care home beds and encouraged care closer to home. Such policies have raised issues about education and training of the homecare workforce, including 6 million insufficiently supported informal carers (10% of the population), the commissioning process, and difficulties in implementing nutritional policies in a widely distributed population. The four devolved nations in the UK (England, Scotland, Northern Ireland and Wales) have developed their own healthcare polices to deal with malnutrition. These generally aim to span across all care settings and various government departments in a co-ordinated manner, but their effectiveness remains to be properly evaluated.


Subject(s)
Malnutrition , Nutrition Policy , Health Facilities/statistics & numerical data , Home Care Services/standards , Hospital Mortality , Hospitalization/statistics & numerical data , Humans , Malnutrition/epidemiology , Malnutrition/therapy , Prevalence , United Kingdom/epidemiology
13.
Dalton Trans ; (27): 5348-54, 2009 Jul 21.
Article in English | MEDLINE | ID: mdl-19565086

ABSTRACT

The synthesis and X-ray crystal structures of the diborane(4) isomers 1,1-B(2){1,2-(NH)(2)C(6)H(4)}(2) and 1,2-B(2){1,2-(NH)(2)C(6)H(4)}(2) are described together with the results of quantum chemical calculations which shed light on their relative stabilities and degree of aromaticity. Spectroscopic data are also provided for both isomers of the 4-methyl aryl derivative. The compound 1,1-B(2){1-O-2-(NH)C(6)H(4)}(2) has also been prepared and structurally characterised but no evidence was obtained for the corresponding 1,2-isomer. The compound 1,1-B(2){1,2-(NH)(2)C(6)H(4)}(2) forms a co-crystal with TCNQ, the structure of which is also reported.

14.
Prev Vet Med ; 71(3-4): 225-40, 2005 Oct 12.
Article in English | MEDLINE | ID: mdl-16153724

ABSTRACT

Spatial heterogeneity and long-distance translocation (LDT) play important roles in the spatio-temporal dynamics and management of emerging infectious diseases and invasive species. We assessed the influence of LDT events on the invasive spread of raccoon rabies through Connecticut. We identified several putative LDT events, and developed a network-model to evaluate whether they became new foci for epidemic spread. LDT was fairly common, but many of the LDTs were isolated events that did not spread. Two putative LDT events did appear to become nascent foci that affected the epidemic in surrounding townships. In evaluating the role of LDT, we simultaneously revisited the problem of spatial heterogeneity. The spread of raccoon rabies is associated with forest cover--rabies moves up to three-times slower through the most heavily forested townships compared with those with less forestation. Forestation also modified the effect of rivers. In the best overall model, rabies did not cross the river separating townships that were heavily forested, and the spread slowed substantially between townships that were lightly forested. Our results suggest that spatial heterogeneity can be used to enhance the effects of rabies control by focusing vaccine bait distribution along rivers in lightly forested areas. LDT events are a concern, but this analysis suggests that at a local scale they can be isolated and managed.


Subject(s)
Rabies/veterinary , Raccoons , Animals , Connecticut/epidemiology , Rabies/epidemiology , Rabies/prevention & control , Rabies virus , Rivers , Space-Time Clustering , Trees
15.
Vector Borne Zoonotic Dis ; 2(2): 77-86, 2002.
Article in English | MEDLINE | ID: mdl-12653301

ABSTRACT

The quantitative analysis of pathogen transmission within its specific spatial context should improve our ability to predict and control the epizootic spread of that disease. We compared two methods for calibrating the effect of local, spatially distributed environmental heterogeneities on disease spread. Using the time-of-first-appearance of raccoon rabies across the 169 townships in Connecticut, we estimated local spatial variation in township-to-township transmission rate using Trend Surface Analysis (TSA) and then compared these estimates with those based on an earlier probabilistic simulation using the same data. Both the probabilistic simulation and the TSA reveal significant reduction in transmission when local spatial domains are separated by rivers. The probabilistic simulation suggested that township-to-township transmission was reduced sevenfold for townships separated by a river. The global effect of this sevenfold reduction is to increase the time-to-first-appearance in the eastern townships of Connecticut by approximately 29.7% (spread was from west to east). TSA revealed a similar effect of rivers with an overall reduction in rate of local propagation due to rivers of approximately 22%. The 7.7% difference in these two estimates reveals slightly different aspects of the spatial dynamics of this epizootic. Together, these two methods can be used to construct an overall picture of the combined effects of local spatial variation in township-to-township transmission on patterns of local rate of propagation at scales larger than the immediate nearest neighboring townships.


Subject(s)
Rabies/epidemiology , Rabies/veterinary , Raccoons/virology , Animals , Computer Simulation , Connecticut/epidemiology , Fresh Water , Geography , Models, Biological , Time Factors
16.
Inorg Chem ; 40(22): 5668-74, 2001 Oct 22.
Article in English | MEDLINE | ID: mdl-11599968

ABSTRACT

Sulfonic acids RSO(2)OH and their metal salts MO(3)SR are versatile catalysts in large-scale industrial cyclization and polymerization processes. Isoelectronic replacement of the oxygen atoms by NR imido groups gives triimidosulfonic acid and triimidosulfonates. The salts form nonaggregated soluble molecules rather than infinite solid-state lattices such as their oxo analogues. In this paper, we present the synthesis and structure of the basic starting material MeS(N(t)Bu)(3)H (1), the metal complexes [Me(2)Al(N(t)Bu)(3)SMe] (2) and [Zn[(N(t)Bu)(3)SMe](2)] (3), and the mixed metal adduct [(thf)Li[(N(t)Bu)(3)SMe].ZnMe(2)] (4). The chelating coordination, rather than the tripodal coordination, cannot be attributed to steric effects of the S-bonded methyl group, as the less demanding Ph-C triple bond C-alkynyl substituent at sulfur in [(thf)(2)Li[(N(t)Bu)(3)SCCPh]] (5) causes the same conformation. S-N bond shortening to the pendant imido group has to be attributed to closed-shell electrostatic attraction rather than to S-N double bonding by valence expansion at the central sulfur atom. Coordination to an additional N-->Zn dative bond in 4 widens the bond length to values normally interpreted as S-N single bonds. We take this fact as experimental evidence that S-N bonding is predominantly governed by electrostatic interaction rather than by valence expansion employing d-orbitals. This was predicted by theoreticians more than a decade ago.

17.
Bone Marrow Transplant ; 27(9): 949-58, 2001 May.
Article in English | MEDLINE | ID: mdl-11436105

ABSTRACT

Helper T lymphocyte precursor (HTLp) frequencies determined by limiting dilution analysis were studied in the graft-versus-host direction to assess the predictive value for outcome in allogeneic BMT. The HTLp frequencies correlated with the degree of HLA disparity. HTLp frequencies from 28 HLA-identical sibling BMT pairs had a median of 1:557 362 (range 1:9511 to <1:2 500 000). The HTLp frequencies from 20 HLA-matched unrelated and partially HLA-matched related BMT pairs had a median of 1:88 110 (range 1:4139-1:736 123). The HLA-identical sibling BMT pairs were split evenly into high and low HTLp frequency groups above and below 1:500 000. There was a trend towards a higher risk for acute GVHD > or =grade II (P = 0.075) in the high frequency group. There was no difference in TRM. The high HTLp frequency group had a significantly higher risk for chronic GVHD (P = 0.04), a significantly lower risk for relapse (P = 0.01), as well as a significantly better overall survival (P = 0.045) and leukaemia-free survival (P = 0.008). The HLA-matched unrelated and partially HLA-matched related BMT pairs were split evenly into high and low HTLp frequency groups above and below 1:90 000. There was a significantly higher risk for acute GVHD > or = grade II (P = 0.007) in the high HTLp frequency group. There was a trend towards a higher TRM in the high HTLp frequency group (P = 0.05). There were no differences in chronic GVHD, risk of relapse, overall survival and leukaemia-free survival. Analyzing all 48 patients the risk of acute GVHD > or = grade II and TRM was significantly higher (P = 0.012 and 0.021, respectively) with HTLp frequencies >1:100 000 and there was a trend towards a higher risk of relapse (P = 0.058) with low HTLp frequencies <1:400 000. Patients in the intermediate HTLp frequency group 1:100 000-1:400 000 had a trend towards improved survival (P = 0.059). The HTLp frequency seems to detect clinically significant differences in alloreactivity, that can be useful in donor selection and graft engineering.


Subject(s)
Bone Marrow Transplantation , Graft vs Host Disease/diagnosis , Graft vs Host Disease/mortality , Graft vs Leukemia Effect , Hematopoietic Stem Cells/cytology , T-Lymphocytes, Helper-Inducer/cytology , Adolescent , Adult , Aged , Bone Marrow Transplantation/immunology , Bone Marrow Transplantation/mortality , CD4 Lymphocyte Count , Female , Follow-Up Studies , Graft vs Host Disease/blood , Hematologic Neoplasms/mortality , Hematologic Neoplasms/therapy , Histocompatibility Testing , Humans , Male , Middle Aged , Prognosis , Severity of Illness Index , Transplantation, Homologous/immunology , Transplantation, Homologous/mortality , Treatment Outcome
18.
J Immunol Methods ; 251(1-2): 109-21, 2001 May 01.
Article in English | MEDLINE | ID: mdl-11292487

ABSTRACT

Helper T lymphocyte precursor (HTLp) frequencies determined by limiting dilution analysis (LDA) have a predictive value for alloreactivity in allogeneic bone marrow transplantation. Methodological problems in LDA include autoreactivity in the responder or stimulator cell populations and interleukin 2 (IL-2) production by the stimulator cells as a response to the responder cells (backstimulation). The extent and impact of these aspects for IL-2 production and HTLp frequency determination were studied by autologous and allogeneic mixed lymphocyte reactions with healthy volunteers and HTLp determinations from bone marrow transplantation donor/recipient pairs. We found that autoreactivity occurred in the unirradiated cells with a reproducible inter-individual variation. The immunogenicity of the stimulator cells was preserved after gamma irradiation with 50 Gy and the risks of autoreactivity and backstimulation were limited. Higher doses of irradiation decreased the immunogenicity. Immune reactions to antigens present in the serum supplement of the culture medium were seen with foetal calf serum and to a lesser extent with pooled human sera. This could be avoided by the use of autologous serum. We were unable to ensure satisfactory culture conditions in serum-free medium. The reproducibility of the HTLp frequency determinations was tested for intra- and inter-assay variation. The coefficients of variation were estimated as 24% and 35%, respectively. This was acceptable considering the range of the HTLp frequencies (1:10(2) to 1:10(7)). The influence of the extent of autoreactivity of the bone marrow donors was investigated in 28 HLA-identical sibling transplantations. We found no correlation between the autoreactivity of the donors and the HTLp frequencies. The extent of autoreactivity of the donor did not correlate with the clinical outcome in terms of acute graft-versus-host disease, treatment-related mortality, risk of relapse and overall survival. In spite of methodological difficulties and interference from autoreactivity and backstimulation, reproducible quantification of clinically significant alloreactivity can be attained.


Subject(s)
Autoimmunity , Lymphocyte Culture Test, Mixed/methods , T-Lymphocytes, Helper-Inducer/immunology , Bone Marrow Transplantation/adverse effects , Bone Marrow Transplantation/immunology , Culture Media , Gamma Rays , Graft Survival/immunology , Graft vs Host Disease/etiology , Graft vs Host Disease/immunology , Hematopoietic Stem Cells/immunology , Hematopoietic Stem Cells/radiation effects , Humans , Interleukin-2/biosynthesis , Lymphocyte Activation , Lymphocyte Culture Test, Mixed/statistics & numerical data , Phytohemagglutinins/pharmacology , Reproducibility of Results , T-Lymphocytes, Helper-Inducer/radiation effects , Transplantation, Homologous
20.
Ambix ; 48(2): 53-5, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11954609
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