RESUMO
Hoof trimming is used to prevent and treat lameness in dairy cows; however, hoof trimming itself increases daily time spent lying down, possibly due to discomfort. We hypothesized that treatment of lame and nonlame cows with an anti-inflammatory analgesic drug at the time of hoof trimming would mitigate discomfort, thereby improving locomotion scores and reducing post-trimming increases in lying time. We further hypothesized that drug treatment would improve post-trimming milk production. Our objective was to determine the effects of treatment with the nonsteroidal anti-inflammatory drug flunixin meglumine (2.2 mg/kg of BW) at the time of hoof trimming on locomotion, lying times, and milk production in lame and nonlame lactating dairy cows. All cows were filmed for locomotion scoring 1 d before and 1, 8, and 28 d after hoof trimming. Daily time spent standing and lying was recorded for 4 d before and 4 wk after hoof trimming, and daily milk production was recorded for 1 wk before and 8 wk after trimming. Thirty minutes before hoof trimming, an intravenous injection of flunixin meglumine (n = 34) or isotonic sterile saline solution (n = 34) was administered to each cow. Then, all cows had their hooves trimmed using the Dutch method. The same treatment was repeated 24 h after hoof trimming. Cows were categorized using baseline locomotion scores as lame (score ≥3/5) or nonlame (score <3/5). Drug treatment did not affect post-trimming changes in locomotion scores, daily lying times, or milk production. In both treatment groups, most cows had the same lameness status (lame or nonlame) at baseline and after treatment, and there was no difference between groups in the number of cows that changed lameness status over time. Lame cows (n = 21) had no significant changes in lying times over the course of the study, whereas nonlame cows (n = 47) had mean daily lying times that were significantly higher than baseline all 4 wk after trimming. Hoof trimming in nonlame cows should be scheduled for a time when increased lying behavior after trimming can be accommodated.
Assuntos
Anti-Inflamatórios não Esteroides , Doenças dos Bovinos , Clonixina , Casco e Garras , Lactação , Coxeadura Animal , Leite , Animais , Bovinos , Feminino , Anti-Inflamatórios não Esteroides/uso terapêutico , Comportamento Animal/efeitos dos fármacos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/terapia , Clonixina/análogos & derivados , Clonixina/farmacologia , Lactação/efeitos dos fármacos , Coxeadura Animal/tratamento farmacológico , Projetos de PesquisaRESUMO
The objective of this study was to evaluate the effect of flunixin meglumine treatment on lameness pain in dairy cows. Twenty-four lactating Holstein cows were enrolled in the study based on visual observation of abnormal locomotion. The primary measurement endpoint was weight-shifting between the rear limbs. Weight-shifting was calculated as the standard deviation of the weight borne on the rear limbs over a 15 min period; this value correlates directly with lameness pain in dairy cows. After collecting baseline weight-bearing data, we randomly assigned cows to 1 of 2 treatment groups: 2.2 mg/kg body weight flunixin meglumine (2 mL/45 kg) or an equivalent volume of isotonic sterile saline solution. Weight-bearing data were collected from each cow at 2, 6, 12, and 24 h after a single intravenous drug treatment. Mean locomotion scores over the 2 d before treatment were 2.38/5 in the flunixin-treated group and 2.43/5 in the saline-treated control group; these values were not significantly different. Weight-shifting values were also not significantly different on either pretreatment day. Cows treated with flunixin meglumine showed significantly less weight-shifting between the rear limbs at 6, 12, and 24 h after treatment compared with saline-treated controls, providing evidence that flunixin meglumine alleviates lameness-associated pain.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Bovinos/fisiologia , Clonixina/análogos & derivados , Indústria de Laticínios/métodos , Coxeadura Animal/tratamento farmacológico , Animais , Clonixina/uso terapêutico , Feminino , Marcha , Lactação , Dor/tratamento farmacológico , Dor/veterinária , Suporte de Carga/fisiologiaRESUMO
The objectives of this study were to evaluate changes in weight shifting between legs while standing on a weighing platform in response to endotoxin-induced clinical mastitis, and to evaluate the effect of the nonsteroidal antiinflammatory drug flunixin meglumine on weight distribution between legs while standing in dairy cattle with endotoxin-induced clinical mastitis. Clinical mastitis was induced in 10 primiparous and 9 multiparous lactating dairy cows (days in milk=55 ± 12; mean ± standard deviation) by intramammary infusion of 100 µg of Escherichia coli lipopolysaccharide (LPS) into the right rear quarter. Four hours later, 10 animals were randomly assigned to receive flunixin meglumine intravenously (2.2mg/kg of body weight; treated group) and 9 received an equivalent volume of sterile isotonic saline solution (control group). Body temperature was monitored rectally 3d before LPS infusion, immediately before LPS infusion, and 4, 7, 10, 13, 16, and 28 h after LPS infusion. The weight applied to each leg was recorded while cows were standing on a weighing platform on the day before the challenge and 7, 10, 13, 16, and 28 h after LPS infusion. Two measures of weight shifting between the rear legs were calculated for each recording session: the standard deviation of the weight applied to the legs over time and the frequency of steps. The LPS infusion resulted in a consistent case of clinical mastitis approximately 4h after the LPS infusion, as assessed by the presence of visible swelling and elevated rectal temperature in all cows. However, control animals had a higher temperature 7h after LPS infusion compared with treated animals (40.8 vs. 39.0°C; standard error of the difference=0.2). Overall, weight shifting between the rear legs was decreased 7h after the LPS infusion compared with baseline, and this decrease was not affected by treatment with flunixin meglumine. It is likely that weight shifting increases friction between the swollen udder and the legs, increasing the pain experienced by the cow. Thus, cows with endotoxin-induced mastitis avoided shifting weight, particularly at the times when the most severe signs of inflammation occurred. Further research is needed to assess the efficacy of flunixin meglumine in mitigating udder pain and the accuracy of behavioral measures such as weight shifting in assessing analgesia in cows with mastitis.
Assuntos
Mastite Bovina/fisiopatologia , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Bovinos/fisiologia , Clonixina/análogos & derivados , Clonixina/farmacologia , Feminino , Membro Posterior/fisiologia , Lipopolissacarídeos/farmacologia , Mastite Bovina/induzido quimicamente , Mastite Bovina/complicações , Dor/tratamento farmacológico , Dor/etiologia , Postura/fisiologia , Suporte de Carga/fisiologiaAssuntos
Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Doenças Profissionais/patologia , Saúde Ocupacional/estatística & dados numéricos , Adulto , Mama , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Carcinoma Ductal de Mama/epidemiologia , Carcinoma Ductal de Mama/genética , Estudos de Casos e Controles , Análise por Conglomerados , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Doenças Profissionais/epidemiologia , Doenças Profissionais/genética , Queensland/epidemiologia , RNA Neoplásico/genética , RNA Neoplásico/isolamento & purificação , Estudos Retrospectivos , Fatores de RiscoRESUMO
Intramuscular injections of drugs and vaccines cause tissue damage and subsequent effects on tenderness and consumer acceptability of beef. In the 2007 National Market Cow and Bull Beef Quality Audit, 100% of plants reported fabricating subprimal cuts such as rib eyes and tenderloins from cow and bull carcasses. Dairy beef quality should therefore be a consideration when injections are given to dairy animals. The discussion about injection site reactions and tenderness has focused on vaccines and antimicrobial drugs with little concern for the effects of reproductive hormones. The objective of this study was to quantify antemortem the effects of semimembranosis/semitendinosis muscle injection of dinoprost and GnRH in lactating dairy cows by estimating the weight of tissue damaged and comparing that with a drug known to cause extensive tissue damage, flunixin meglumine. Tissue damage was estimated from previously reported equations for grams of muscle tissue damage based on area under the curve of serum concentrations of the muscle enzyme creatine kinase over time. Dinoprost and flunixin injection both caused a significantly increased estimate of muscle tissue damaged compared with needle only (P = 0.0351 and 0.0355, respectively). Dinoprost and flunixin caused a marginally significant increased muscle tissue damage compared with GnRH (P = 0.1394 and 0.1475, respectively). No statistically significant difference was found between the estimated weight of muscle tissue damaged by flunixin compared with dinoprost (P = 1.0000), or by saline compared with GnRH (P = 0.7736) or needle only (P = 0.4902). The assumption that reproductive hormones are less damaging than vaccines and antimicrobial drugs should be examined more closely, including postmortem evaluation of injection site lesions and effects on tenderness.
Assuntos
Dinoprosta/efeitos adversos , Hormônio Liberador de Gonadotropina/efeitos adversos , Carne/normas , Animais , Bovinos , Clonixina/análogos & derivados , Clonixina/farmacologia , Feminino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologiaRESUMO
Candida albicans is an oral commensal yeast that causes oropharyngeal candidiasis (OPC) in immunocompromised individuals. The immunological pathways involved in OPC have been revisited after the interleukin-17 (IL-17) pathway was implicated in fungal immunity. We studied immediate (<24 h) and adaptive (3-6 day) IL-12 and IL-23-17 pathway activation in naive p40(-/-) mice, which lack IL-12 and IL-23 and develop severe, chronic OPC upon oral inoculation with C. albicans. Macrophages from p40(-/-) mice were less efficient than C57BL/6J controls at killing C. albicans in vitro but very low numbers in the oral mucosae of infected C57BL/6J mice suggest that they are not critical in vivo, at least in this strain. Migration of macrophages to regional lymph nodes of infected p40(-/-) mice was impaired; however, dendritic cell migration was not affected. Recombinant IL-12 therapy provided only temporary relief from OPC, suggesting that IL-23 is required for full protection. In C57BL/6J mice, but not p40(-/-) mice, messenger RNAs encoding IL-23p19 and IL-17 were induced in the oral mucosa within 24 h of infection (6 ± 0.6 and 12 ± 2.7-fold). By day 6 of infection in C57BL/6J mice, IL-17A messenger RNA level had increased 5.1 ± 1.8 and 83 ± 21-fold in regional lymph nodes and oral tissues respectively. Ablation of p40 was associated with delayed or abrogated induction of IL-17A pathway targets (monocyte chemoattractant protein-1, IL-6 and macrophage inflammatory protein-2), and a lack of organized recruitment of neutrophils to the infected oral mucosa. Overall our data show that the IL-23-17A axis is activated early in the oral mucosae of immunologically naive mice with OPC.
Assuntos
Candidíase Bucal/imunologia , Interleucina-12/imunologia , Interleucina-17/imunologia , Interleucina-23/imunologia , Animais , Candidíase Bucal/genética , Quimiocina CCL2/imunologia , Quimiocina CXCL2/imunologia , Doença Crônica , Células Dendríticas/imunologia , Modelos Animais de Doenças , Feminino , Imunidade Inata , Subunidade p40 da Interleucina-12/deficiência , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mucosa Bucal/imunologia , Neutrófilos/imunologia , Fagocitose , Proteínas Recombinantes , Organismos Livres de Patógenos Específicos , Migração Transendotelial e TransepitelialRESUMO
Sixty-six lactating cows were either injected with flunixin meglumine (2.2mg/kg of BW) immediately before hoof trimming (n=28), injected with a saline solution immediately before hoof trimming (n=28), or injected with a saline solution immediately before sham hoof trimming (control; n=10). Gait scores, time spent lying down, frequency of steps, and how cows distributed their weight among their legs when standing before, during, and after injections were measured to assess whether automated measures of activity and weight distribution can detect lameness and the effects of pain mitigation during hoof trimming. The overall gait score was positively correlated with the variability of the weight applied the rear legs (r=0.32) and negatively correlated with the rear leg weight ratio (LWR; r=-0.52) and the frequency of steps (r=-0.43). The rear LWR was the best predictor of cows being lame (NRS >3), accounting for 27% of the variation in the likelihood of a cow being lame and 11% of the variation in the likelihood of a cow having an infectious hoof lesion. For each 5% increase in the rear LWR, the likelihood of being lame decreased by 30% (odds ratio = 0.71; 95% confidence interval = 0.56, 0.90) and the likelihood of being afflicted with an infectious hoof disease decreased by 20% (odds ratio = 0.81; 95% confidence interval = 0.67, 0.98). Neither hoof trimming nor a combination of hoof trimming and analgesia significantly affected gait score or any measure of weight distribution. Daily lying time increased during the 2 d following hoof trimming independently of the flunixin meglumine injection. However, this increase was not sustained for longer than 2 d when cows were injected with flunixin meglumine. Measures of weight shifting between legs while cows are standing and measures of activity show great potential as automated methods of detecting lameness and may also provide a tool for future evaluation of lameness therapies, such as hoof trimming and pain mitigation.
Assuntos
Analgesia/veterinária , Analgésicos/farmacologia , Bovinos/fisiologia , Clonixina/análogos & derivados , Marcha/efeitos dos fármacos , Casco e Garras , Atividade Motora/efeitos dos fármacos , Animais , Peso Corporal/fisiologia , Clonixina/farmacologia , Indústria de Laticínios/métodos , FemininoRESUMO
The effect of intravenous administration of the steroidal drug isoflupredone acetate on lactating dairy cows with mastitis induced using gram-negative bacterial endotoxin was investigated. Cows were randomly assigned to one of four treatment groups: untreated controls, isoflupredone acetate only, mastitis only, and mastitis plus isoflupredone acetate. Isoflupredone acetate was given to treated groups at a dose of 20 mg intravenously, once. Mastitic cows receiving treatment were given isoflupredone acetate after the development of clinical signs. When compared with untreated mastitic controls, cows with endotoxin-induced mastitis treated with isoflupredone acetate did not exhibit measurable differences in heart rate, rectal temperature, rumen motility, or changes in mammary gland surface area in the 14 h following the administration of intramammary endotoxin. Healthy cows treated with isoflupredone acetate had a higher heart rate over the 14 h after drug administration than did untreated healthy controls. When compared with untreated mastitic controls, cows treated with isoflupredone acetate did not exhibit statistically significant differences in milk production following endotoxin-induced mastitis.
Assuntos
Endotoxinas , Fluprednisolona/análogos & derivados , Fluprednisolona/farmacologia , Mastite Bovina/tratamento farmacológico , Animais , Temperatura Corporal , Bovinos , Feminino , Fluprednisolona/uso terapêutico , Frequência Cardíaca , Cinética , Lactação , Glândulas Mamárias Animais/patologia , Mastite Bovina/induzido quimicamente , Mastite Bovina/fisiopatologia , Contração Muscular , Rúmen/fisiopatologiaRESUMO
Deposition of malathion and permethrin onto grass surfaces, after ultra-low volume (ULV) application, was studied in a suburban neighborhood in Saginaw County, Michigan. Commercial concentrates of malathion (Cythion ULV) and permethrin (Biomist 4 + 12) were sprayed using a truck-mounted ULV aerosol generator. Sod-grass blocks (0.18 m2) were placed in the frontyard and backyard of homes in the neighborhood at 4 distances to 91.4 m from the road where applications were made. Grass samples were taken from the sod blocks before application and at 15 min, 12 h, 24 h, and 36 h after application. Samples were extracted with solvent, and extractions were subjected to gas-liquid chromatography for detection of malathion and permethrin. Ranges of detection for malathion were 0.0-16.6 mg/0.18 m2 and for permethrin were 0.0-25.9 mg/0.18 m2. Most detections were from samples taken nearest the road at 15 min after application. Detections declined as a logarithmic function of time after application and as an exponential function of distance from the road.
Assuntos
Malation , Controle de Mosquitos , Resíduos de Praguicidas , Piretrinas , Michigan , Permetrina , PoaceaeRESUMO
The prochiral sila-ketone acetyldimethyl(phenyl)silane (1) was reduced enantioselectively into (R)-(1-hydroxyethyl)dimethyl(phenyl)silane [(R)-2] using resting cells of the commercially available yeast Saccharomyces cerevisiae (DHW S-3) as the biocatalyst. The bioconversion was performed on a 2.0-g scale in a 5-1 bioreactor. Starting with a substrate (1) concentration of 0.4 g.l-1, the highest production rate measured for this bioconversion was about 45-55 mumol (R)-2.l-1.min-1. After an incubation time of 1 h, all substrate in the medium had been converted, either biocatalytically reduced to (R)-2 or (probably chemically) converted into dimethyl(phenyl)silanol (Me2PhSiOH). After extraction of the cell-free medium with ethyl acetate/dichloromethane and subsequent purification of the extract by Kugelrohr distillation and chromatography on silica gel (medium-pressure liquid chromatography), 800 mg (yield 40%) of the bioconversion product (R)-2 was isolated. As shown by HPLC studies (cellulose triacetate as the chiral stationary phase) and 1H-nuclear magnetic resonance experiments (after derivatization of the bioconversion product with a chiral auxiliary agent), compound (R)-2 was almost enantiomerically pure (> 99% enantiomeric excess).
Assuntos
Saccharomyces cerevisiae/metabolismo , Silanos/metabolismo , Biotecnologia , Catálise , Cinética , Estrutura Molecular , Oxirredução , Silanos/química , Silanos/isolamento & purificação , EstereoisomerismoRESUMO
Liquid Bacillus thuringiensis H-14 (Acrobe) was applied from fixed-wing aircraft at a rate of 4.68 liters of water-insecticide mixture (1.17 liter concentrate) per hectare to woodland pools in Michigan. A post-treatment larval survey indicated an 88.5% reduction in Aedes species larvae. A volume median diameter of 208 microns was determined.
Assuntos
Aedes , Bacillus thuringiensis , Controle Biológico de Vetores/métodos , Animais , Ecologia , Larva , Michigan , Tamanho da PartículaRESUMO
We selected for study drivers who were sentenced either to jail or a certified driver intervention program (DIP) in Franklin County, Ohio, in 1987 after their first drunken driving (DUI) conviction. Because each drunken driving charge was assigned to one of a pool of 15 judges with widely varying sentencing patterns, there was no apparent bias in subject allocation to the two treatments. For the jailed (n = 124) and DIP (n = 218) cohorts, we compared the likelihood of subsequent impaired driving, as evidenced by rearrest for a new alcohol-related driving offense or involvement in a car crash after drinking in the 4 years following the study-selected event. After controlling for potentially important covariates, such as gender, age, race, blood alcohol concentration, additional charges filed at the time of arrest, and driving history, we derived logistic regression results indicating that DIP attendees had significantly lower rates of subsequent impaired driving. Drivers who had no prior history of at least one non-DUI alcohol-related offense were significantly more likely to display additional impaired driving when jailed as opposed to those enrolled in a DIP (odds ratio [OR] = 2.53, confidence interval [CI] = 1.44, 4.45), while those with previous alcohol-related offenses may have fared better in jail (OR = .56, CI = .11, 2.76). Drivers younger than 21 years of age were also at elevated risk for repeat offenses (OR = 2.46, CI = 1.13, 5.35). DIPs appear most effective when used for persons who have not had previous alcohol-related crashes or driving offenses.
Assuntos
Intoxicação Alcoólica , Condução de Veículo/legislação & jurisprudência , Acidentes de Trânsito , Adulto , Intoxicação Alcoólica/reabilitação , Condução de Veículo/educação , Intervalos de Confiança , Feminino , Seguimentos , Humanos , Masculino , Razão de Chances , Prisioneiros , Fatores de Risco , Assunção de Riscos , Controle Social FormalRESUMO
1. The total sialic acid content of human gastric aspirates was measured using a colorimetric assay. Care was taken to optimize the assay and to eliminate interference. 2. The sialic acid content of gastric aspirates collected under resting conditions from 77 patients with non-ulcer dyspepsia was found to decrease with age from > 100 micrograms/ml at 25 years and younger to < 20 micrograms/ml above 70 years of age. 3. Analysis of the sialic acids by gas chromatography, mass spectrometry and thin-layer chromatography showed the presence of N-acetylneuraminic acid and two O-acylated derivatives, 9-O-acetyl- and 9-O-lactyl-N-acetylneuraminic acids. These forms were predominantly glycosidically bound. 4. Thin-layer chromatographic analysis of individual aspirate samples showed that the O-acetylated sialic acids were present in all samples, with a maximum of 25% and a minimum of 5% of the total sialic acids.
Assuntos
Envelhecimento/metabolismo , Suco Gástrico/metabolismo , Ácidos Siálicos/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Cromatografia em Camada Fina , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Suco Gástrico/química , Humanos , Masculino , Pessoa de Meia-Idade , Ácidos Siálicos/análiseRESUMO
Sialidase activity in normal faecal extracts showed a preference for mucin-related glycoprotein and oligosaccharide substrates, but the presence of two or more O-acetyl esters at positions C7-C9 on the sialic acids retarded the rate of hydrolysis. A specific sialate O-acetyl esterase was detected with a lower total activity relative to sialidase with mucin substrates and having a pH optimum of 7.8 and a KM of approximately 1 mM sialate O-acetyl ester. A specific glycosulfatase activity was found in faecal extracts using the substrate lactit-[3H]ol 6-O-sulfate with a pH optimum of pH 5.0 and a KM of approximately 1 mM. Faecal extracts from ulcerative colitis (UC) patients had higher sialate O-acetyl esterase and glycosulfatase activity, while mucin sialidase activity was unchanged. Metabolically labelled mucin isolated from UC patients contained less sulfate and had lower sialic acid O-acetylation compared with normal mucin. Colonic mucin was degraded more efficiently by faecal extracts from UC patients compared with normal extracts. The UC mucin was degraded more rapidly than the normal mucin by faecal enzyme extracts from both normal and UC subjects.
Assuntos
Hidrolases de Éster Carboxílico/fisiologia , Colo/metabolismo , Enterobacteriaceae/enzimologia , Mucinas/metabolismo , Neuraminidase/fisiologia , Sulfatases/fisiologia , Acetilação , Acetilesterase , Sequência de Carboidratos , Hidrolases de Éster Carboxílico/química , Colite Ulcerativa/enzimologia , Colite Ulcerativa/metabolismo , Fezes/enzimologia , Humanos , Dados de Sequência Molecular , Neuraminidase/antagonistas & inibidores , Ácidos Siálicos/análise , Sulfatases/químicaRESUMO
Six male patients with severe psoriatic arthritis (PA) unresponsive to various topical and systemic therapies have been treated with oral cyclosporin A (CyA; Sandimmun) solution at daily doses ranging usually from 1.5 to 5.0 mg/kg. In 1 case the dose had to be increased to 7 mg/kg/day. At initiation of CyA therapy skin involvement was between 40 and 90% of total body surface. Initiation of CyA therapy resulted in marked improvement of skin lesions within 2-7 weeks accompanied by impressive relief from arthralgias and improvement of joint function. The requirement for nonsteroidal anti-inflammatory drugs was markedly reduced in all cases. All patients in whom CyA therapy was continued remained clinically stable for several months (follow-up period 2-7 months). Although mild to moderate relapses occurred, rebound phenomena were not observed after discontinuation of treatment. Side effects which comprised serum creatinine increases in 3 out of 6 cases were reversed by adjustment of CyA dosage.
Assuntos
Artrite Psoriásica/tratamento farmacológico , Ciclosporina/administração & dosagem , Administração Oral , Adulto , Idoso , Ciclosporina/uso terapêutico , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
The pattern of mucin synthesis and secretion in mucosal biopsies from the proximal ileum, distal ileum, rectum and pouch before and after ileostomy closure was monitored in patients undergoing restorative proctocolectomy by metabolic labelling with [3H]glucosamine and [35S]sulphate and compared with the mucin histochemistry in each patient. Metabolic labelling clearly demonstrated a reduction in sulphation associated with the rectal mucosa in colitis. Significant differences in the turnover of isolated secreted mucin between proximal and distal ileum and rectum were also found, as was a metaplastic change towards a colonic-type mucosa in the pouch before and after ileostomy closure relative to the proximal and distal ileum, and rectum. This technique can be used to monitor colonic metaplasia in the pouch mucosa and is suitable for comparative studies where mucin changes are implicated.
Assuntos
Íleo/metabolismo , Mucinas/metabolismo , Proctocolectomia Restauradora , Reto/metabolismo , Adulto , Idoso , Feminino , Histocitoquímica , Humanos , Íleo/patologia , Íleo/cirurgia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Pessoa de Meia-Idade , Técnicas de Cultura de Órgãos , Reto/patologia , Reto/cirurgiaRESUMO
Oligosaccharide side chains of human colonic mucins contain O-acetylated sialic acids and glycosulfate esters. Although these substituents are considered to protect the chains against degradation by bacterial glycosidases, sialate O-acetylesterase, N-acetylneuraminate lyase, and glycosulfatase activities have been found in fecal extracts. To better define the source of these activities, we measured extracellular and cell-bound sialidase, sialate O-acetylesterase, N-acetylneuraminate lyase, arylesterase, and glycosulfatase activities produced by 23 isolates of human fecal bacteria grown anaerobically in a hog gastric mucin culture medium; these represented dominant populations of fecal anaerobes, facultative anaerobes, and the subset of mucin oligosaccharide-degrading bacteria. Every strain produced sialidase and high levels of arylesterase, and all but five facultative anaerobes produced sialate O-acetylesterase. Sialic acids containing 2 mol or more of O-acetyl ester per mol of sialic acid were cleaved from mucin glycoproteins more slowly by sialidases of mucin oligosaccharide-degrading stains than were sialic acids containing 1 or 0 mol, and only N-acetyl- and mono-O-acetylated sialic acids were recovered from enzyme digests of a mucin containing di-O-acetylated sialic acids. No detectable N-acetylneuraminate lyase activity was produced by any strain, but low activity was induced by increasing the glycoprotein-bound sialic acid concentration in the culture medium of six Escherichia coli strains. Using lactitol-6-sulfate as a substrate, we found weak glycosulfatase activity in the partially purified, concentrated enzyme mixture in the culture supernatants of four mucin oligosaccharide-degrading strains but in none of the unconcentrated culture fractions. We conclude that the presence of two or more O-acetyl groups on sialic acids inhibits enteric bacterial sialidases but that production of sialate O-acetylesterases by several populations of enteric bacteria lessens the likelihood that mucin oligosaccharide chains terminating in O-acetylated sialic acids are protected from degradation. Sialate O-acetylesterases have a role in bacterial degradation of mucin glycoproteins in the human colon.
Assuntos
Bactérias/enzimologia , Hidrolases de Éster Carboxílico/biossíntese , Colo/metabolismo , Fezes/microbiologia , Mucinas/metabolismo , Neuraminidase/biossíntese , Oxo-Ácido-Liases/biossíntese , Sulfatases/biossíntese , Acetilação , Acetilesterase , Estabilidade Enzimática , Humanos , Ácido N-Acetilneuramínico , Ácidos Siálicos/metabolismoRESUMO
The recreational use of nitrous oxide is widespread. Nitrous oxide for recreational use is usually obtained from anesthesia tanks or whipped-cream machine chargers or cans. Twenty previously described deaths associated with recreational nitrous-oxide use describe anesthesia tanks and whipped-cream machine dispensors as a source. Five deaths associated with nitrous oxide use are presented; two involving whipped-cream cannisters as the source, two involving anesthesia tanks, and one involving a racing fuel tank as a source of nitrous oxide. Autopsy findings in our cases were subtle or negative, but usually suggestive of asphyxia. Through a laboratory simulation, we have confirmed that nitrous oxide displaces oxygen in a closed space, which probably leads to asphyxia. A review of the literature, neuropharmacology, and pathophysiology of nitrous oxide use is also presented.