RESUMO
OBJECTIVES: This scoping review aims to comprehensively assess current surgical interventions for bilateral vocal fold paralysis (BVFP), addressing the heterogeneity in treatment outcomes. Additionally, it explores the potential role of soft robotics as an innovative approach to improve outcomes in BVFP management. METHODS: This scoping review systematically examines literature from MEDLINE, Embase, and Scopus databases. Inclusion criteria encompass studies related to BVFP management with measurable subjective or objective outcomes. Studies with populations solely under the age of 18 were excluded. Four reviewers independently screened 2263 studies, resulting in the selection of 125 papers for data extraction. Information included study characteristics, interventions, and outcomes. Data synthesis involved both quantitative and qualitative analyses. RESULTS: The review identified 145 surgical interventions grouped into seven types: tracheostomy, cordectomy, arytenoidectomy, lateralization, combined procedures and others. Outcome measures fit into the following categories: "objective voice," "subjective voice," "aerodynamics," "dyspnea," "decannulation," "swallow," and "quality of life." Positive outcomes were predominant across all interventions, with arytenoidectomy and cordectomy showing relatively lower rates of successful objective and subjective voice outcomes. This could be the result of prioritizing improved airway status. Soft robotics is hypothesized as a potential solution to the limitation of current interventions sacrificing voice for breathing. CONCLUSIONS: The main aim of current surgical interventions for BVFP is expanding glottic aperture. Yet achieving optimal outcomes remains elusive due to complex airflow dynamics and potential impacts on phonatory function and swallowing. The current review underscores the need for a more nuanced, personalized approach, considering individual anatomical and physiological variations. Soft robotics emerges as a promising avenue to address this variability. However, challenges such as implantation procedures, long-term care, and patient education require careful consideration. Collaboration between medical professionals, engineers, and robotics specialists is essential for translating these principles into practical solutions.
RESUMO
A study was conducted to determine if homologous integrons occurred in Escherichia coli and Salmonella spp. within livestock production sites in the United States and Thailand suggesting transfer of genetic resistance elements between those organisms. Fecal samples were collected via rectal swabs from live swine in the United States and Thailand, and cloacal swabs from live chickens in Thailand, and killed chickens at a U.S. abattoir. Isolates were derived only from farms harboring both Salmonella and E. coli, resulting in the inclusion of 571 E. coli and 98 Salmonella isolates derived from both livestock species in the United States and Thailand. Class 1 integron variable regions were detected using polymerase chain reaction targeting 5' and 3' conserved sequences. When integron-positive E. coli and Salmonella from the same farm had identical amplicon patterns, polymerase chain reaction products were sequenced to determine homology. Nine integron amplicons, with sizes ranging from 0.5 to 2.5 kb, were observed in bacterial isolates, and we found a single swine farm in Thailand from which identical amplicons were observed in both E. coli and Salmonella. Sequence analysis revealed a 1.0 kb amplicon common to both bacteria contained an aadA1 gene cassette encoding aminoglycoside 3'-adenyltransferase, conferring resistance to streptomycin and spectinomycin. A 2.0 kb amplicon was also found in both types of bacteria from that farm, containing an aadA5 gene encoding aminoglycoside 3'-adenyltransferase, an additional reading frame, orfD, with unknown function, and a dfrA17 gene encoding dihydrofolate reductase, conferring resistance to trimethoprim. Further analyses determined the amplicons were contained on plasmid DNA in both E. coli and Salmonella, and a plasmid of similar size was identified in both species and was found to harbor the class 1 integron. Our results indicate that while in most cases, integrons of coexisting E. coli and Salmonella differed, identical integron amplicons were found in those species from a single swine farm in Thailand, suggesting horizontal transfer between these two organisms may have occurred on-farm.
Assuntos
Animais Domésticos/microbiologia , DNA Bacteriano/genética , Escherichia coli/genética , Transferência Genética Horizontal , Integrons/genética , Salmonella/genética , Animais , Galinhas/microbiologia , Cloaca/microbiologia , DNA Bacteriano/isolamento & purificação , Farmacorresistência Bacteriana/genética , Escherichia coli/isolamento & purificação , Fezes/microbiologia , Feminino , Variação Genética , Masculino , Plasmídeos/isolamento & purificação , Plasmídeos/metabolismo , Reação em Cadeia da Polimerase , Reto/microbiologia , Salmonella/isolamento & purificação , Sus scrofa/microbiologia , Tailândia , Estados UnidosRESUMO
To determine effects of anti-Salmonella egg yolk antibodies on shedding and antibiotic resistance of Salmonella enterica Typhimurium, newly weaned pigs were randomly assigned to six dietary treatments. These treatment groups were (i) a control (basal) diet without additives and similar diets with (ii) egg yolk powder derived from chickens challenged with Salmonella Typhimurium antigens, (iii) a commercial egg yolk powder control, (iv) apramycin for 14 days followed by carbadox, (v) oxytetracycline, or (vi) spray-dried plasma protein. Treatments were provided beginning on day 3 of the trial, and all pigs were challenged with 5 ml of 10(8) CFU/ml Salmonella Typhimurium on day 7. Fecal samples were collected on days 0, 7, 8, 12, 14, 21, 58, 88, and 118 for isolation of Salmonella and Escherichia coli to determine shedding and antibiotic resistance patterns. Body weights, white blood cell counts, and plasma concentrations of anti-Salmonella immunoglobulin G and porcine interleukin 1beta were analyzed as indicators of animal health. The percentage of pigs shedding Salmonella was lower for antibiotic treatment groups compared with other groups; however, resistance was greater in E. coli from pigs fed antibiotics than in pigs in other treatment groups. Health and performance indicators (pig weight gains, white blood cell counts, and plasma concentrations of anti-Salmonella antibodies) did not differ between treatment groups. These studies indicate that feeding egg yolk containing anti-Salmonella immunoglobulin Y may not be effective in controlling shedding of Salmonella in pigs.
Assuntos
Anticorpos Antibacterianos/administração & dosagem , Gema de Ovo , Fezes/microbiologia , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella/crescimento & desenvolvimento , Suínos/microbiologia , Ração Animal , Animais , Contagem de Colônia Microbiana , Farmacorresistência Bacteriana , Gema de Ovo/imunologia , Gema de Ovo/microbiologia , Escherichia coli/crescimento & desenvolvimento , Contagem de Leucócitos/veterinária , Distribuição Aleatória , Salmonella/imunologia , Salmonelose Animal/prevenção & controle , Suínos/crescimento & desenvolvimento , Doenças dos Suínos/prevenção & controle , Aumento de PesoRESUMO
The use of antimicrobial compounds in food animal production provides demonstrated benefits, including improved animal health, higher production and, in some cases, reduction in foodborne pathogens. However, use of antibiotics for agricultural purposes, particularly for growth enhancement, has come under much scrutiny, as it has been shown to contribute to the increased prevalence of antibiotic-resistant bacteria of human significance. The transfer of antibiotic resistance genes and selection for resistant bacteria can occur through a variety of mechanisms, which may not always be linked to specific antibiotic use. Prevalence data may provide some perspective on occurrence and changes in resistance over time; however, the reasons are diverse and complex. Much consideration has been given this issue on both domestic and international fronts, and various countries have enacted or are considering tighter restrictions or bans on some types of antibiotic use in food animal production. In some cases, banning the use of growth-promoting antibiotics appears to have resulted in decreases in prevalence of some drug resistant bacteria; however, subsequent increases in animal morbidity and mortality, particularly in young animals, have sometimes resulted in higher use of therapeutic antibiotics, which often come from drug families of greater relevance to human medicine. While it is clear that use of antibiotics can over time result in significant pools of resistance genes among bacteria, including human pathogens, the risk posed to humans by resistant organisms from farms and livestock has not been clearly defined. As livestock producers, animal health experts, the medical community, and government agencies consider effective strategies for control, it is critical that science-based information provide the basis for such considerations, and that the risks, benefits, and feasibility of such strategies are fully considered, so that human and animal health can be maintained while at the same time limiting the risks from antibiotic-resistant bacteria.
Assuntos
Criação de Animais Domésticos/métodos , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana , Medicina Veterinária/métodos , Criação de Animais Domésticos/normas , Animais , Bactérias/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Microbiologia de Alimentos , Humanos , Testes de Sensibilidade Microbiana , Medicina Veterinária/normasRESUMO
Escherichia coli isolates (n = 617) from fecal samples of healthy and diarrheal pigs, pig farmers, and nonfarmers were analyzed for class 1 integrons. Three hundred ninety-two isolates (63.5%) were positive for class 1 integrons, based on the presence of intI1, with seventy-one of those isolates (11.5%) harboring all three conserved genes (intI1, qacEdelta1, and sul1) known to be associated with class 1 integrons. The presence of integrons was associated with isolate origin. Integrons were more prevalent in isolates from most pig groups than in isolates from pig farmers and nonfarmers. Selected integron-positive and integron-negative isolates were tested for resistance to 16 antimicrobials. All integron-positive swine isolates were multidrug resistant to at least three antimicrobial agents, demonstrating resistance to 14 different antibiotics that included sulphamethoxazole (100%), tetracycline (97.1%), ampicillin (92.8%), streptomycin (89.9%), trimethoprim-sulphamethoxazole (88.1%), nalidixic acid (60.9%), chloramphenicol (58.0%), kanamycin (55.1%), cephalothin (44.9%), gentamicin (39.1%), ciprofloxacin (33.3%), cefoxitin (8.7%), amoxicillin-clavulanic acid (5.8%), and amikacin (2.9%). All isolates were susceptible to ceftiofur and ceftriaxone. Forty-seven resistance patterns were observed among 69 integron-positive swine and swine farmer isolates. The most frequent pattern was tetracycline-ciprofloxacin-gentamicin-nalidixic acid-sulphamethoxazole-trimethoprim-sulphamethoxazole-kanamycin-ampicillin-streptomycin (10.1%), which was found in diarrheal and healthy pigs. This study shows that integrons and multidrug-resistant commensal bacteria are common and appear to be a significant aspect of microbial communities associated with pigs and humans in southern Thailand.
Assuntos
Antibacterianos/farmacologia , Reservatórios de Doenças , Farmacorresistência Bacteriana/genética , Escherichia coli , Fezes/microbiologia , Animais , Portador Sadio , Reservatórios de Doenças/veterinária , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Humanos , Integrons , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , Prevalência , Suínos/microbiologia , Doenças dos Suínos/microbiologia , Tailândia/epidemiologiaRESUMO
The goal of this study was to assess the prevalence of antimicrobial resistance and class 1 integrons, including integron-associated genes, in 24 Escherichia coli isolates from dairy farms. Escherichia coli isolates (n = 14) from dairy cows with mastitis (ECDM), Shiga toxin-producing (STEC) O157:H7 from cull dairy cow fecal samples (n = 9) and bulk tank milk (n = 1) were evaluated for sensitivity to 19 antimicrobial agents used commonly in human and/or veterinary medicine. Multiplex PCR was used to determine presence of genes associated with class 1 integrons (intI1, qacEDelta1, and sulI1). Class 1 integrons were found only in eight of 10 isolates (one STEC O157:H7 and seven ECDM) that demonstrated antimicrobial resistance, and seven of these were resistant to two or more antimicrobial agents. Eight of 10 STEC O157:H7 and six of 14 ECDM were susceptible to all commonly used antibiotics. Five ECDM demonstrated multiple resistances to four or more antibiotics. Most of the 24 isolates examined exhibited resistance against sulfamethoxazole, followed by streptomycin and tetracycline. STEC O157:H7 strains had less prevalence of antibiotic resistance and integron carriage than ECDM. The multiplex PCR method developed for detection of intI1, qacEDelta1, and sulI1 can be used routinely for monitoring presence of these genes. Class 1 integrons were found in eight of 10 E. coli strains that demonstrated antimicrobial resistance; seven of these were resistant to two or more antibiotics. It appears that integrons played a role in the incidence of antimicrobial resistance of the strains used in this study.
Assuntos
Indústria de Laticínios , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Integrons/genética , Animais , Bovinos , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/genética , Escherichia coli O157/metabolismo , Fezes/microbiologia , Feminino , Mastite Bovina/microbiologia , Testes de Sensibilidade Microbiana , Leite/microbiologia , Reação em Cadeia da Polimerase , Toxina Shiga/biossínteseRESUMO
The potential impact on human health from antibiotic-resistant bacteria selected by use of antibiotics in food animals has resulted in many reports and recommended actions. The U.S. Food and Drug Administration Center for Veterinary Medicine has issued Guidance Document 152, which advises veterinary drug sponsors of one potential process for conducting a qualitative risk assessment of drug use in food animals. Using this guideline, we developed a deterministic model to assess the risk from two macrolide antibiotics, tylosin and tilmicosin. The scope of modeling included all label claim uses of both macrolides in poultry, swine, and beef cattle. The Guidance Document was followed to define the hazard, which is illness (i) caused by foodborne bacteria with a resistance determinant, (ii) attributed to a specified animal-derived meat commodity, and (iii) treated with a human use drug of the same class. Risk was defined as the probability of this hazard combined with the consequence of treatment failure due to resistant Campylobacter spp. or Enterococcus faecium. A binomial event model was applied to estimate the annual risk for the U.S. general population. Parameters were derived from industry drug use surveys, scientific literature, medical guidelines, and government documents. This unique farm-to-patient risk assessment demonstrated that use of tylosin and tilmicosin in food animals presents a very low risk of human treatment failure, with an approximate annual probability of less than 1 in 10 million Campylobacter-derived and approximately 1 in 3 billion E. faecium-derived risk.
Assuntos
Bactérias/efeitos dos fármacos , Resíduos de Drogas/análise , Macrolídeos/administração & dosagem , Carne/análise , Saúde Pública , Medicina Veterinária/métodos , Doenças dos Animais/tratamento farmacológico , Animais , Animais Domésticos , Bactérias/crescimento & desenvolvimento , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/veterinária , Resistência Microbiana a Medicamentos , Microbiologia de Alimentos , Humanos , Macrolídeos/efeitos adversos , Testes de Sensibilidade Microbiana , Medição de Risco , Estados Unidos , United States Food and Drug AdministrationRESUMO
OBJECTIVES: To determine the prevalence of integron-mediated antibiotic resistance in a diverse sample set of Salmonella enterica isolated from animals. MATERIALS AND METHODS: Multiplex PCR was used to detect class 1 integron gene sequences, and integron gene cassettes were identified by PCR mapping. Susceptibility to 18 antibiotics or antibiotic combinations commonly used in either human or veterinary medicine was measured using a microdilution method, and statistical comparisons of the frequency of resistance between groups were made using Fisher's two-sided probability test. Genotypic comparisons of isolates were made following pulsed-field gel electrophoresis of genomic DNA. RESULTS: Thirty-two (30.8%) of 104 isolates contained class 1 integron sequences. Integron-positive isolates represented 15 different S. enterica serovars, were obtained from nine different animal species and had a higher frequency of non-integron-mediated antibiotic resistance (P < 0.05) compared with integron-negative isolates. One non-Typhimurium isolate (S. enterica Meleagridis) contained an SGI1 genomic island, including the antibiotic resistance gene cluster. CONCLUSIONS: These data demonstrate that integron-mediated antibiotic resistance is common among diverse Salmonella serovars, many of them rare. In addition, SGI1 is not limited to Salmonella enterica Typhimurium DT104 or other commonly isolated serovars.
Assuntos
Genes Bacterianos/genética , Integrons/genética , Salmonella enterica/genética , Animais , Animais Domésticos , Antibacterianos/farmacologia , DNA Bacteriano/química , DNA Bacteriano/genética , Farmacorresistência Bacteriana , Eletroforese em Gel de Campo Pulsado , Testes de Sensibilidade Microbiana , Família Multigênica , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Salmonella enterica/efeitos dos fármacosRESUMO
The objective of this study was to characterize Escherichia coli isolates from dairy cows/feedlots, calves, mastitis, pigs, dogs, parrot, iguana, human disease, and food products for prevalence of Shiga toxin-producing E. coli (STEC) virulence markers. The rationale of the study was that, isolates of the same serotypes that were obtained from different sources and possessed the same marker profiles, could be cross-species transmissible. Multiplex polymerase chain reaction (PCR) was used to detect presence of genes encoding Shiga toxin 1 and 2 (stx1 and stx2), H7 flagella (flicC), enterohemolysin (hly) and intimin (eaeA) in E. coli isolates (n = 400). Shiga toxin-producing isolates were tested for production of Shiga toxins (Stx1 and Stx2 and enterohemolysin. Of the E. coli O157:H7/H- strains, 150 of 164 (mostly human, cattle, and food) isolates were stx+. Sixty-five percent of O157 STEC produced both Stx1 and Stx2; 32% and 0.7% produced Stx2 or Stx1, respectively. Ninety-eight percent of O157 STEC had sequences for genes encoding intimin and enterohemolysin. Five of 20 E. coli O111, 4 of 14 O128 and 4 of 10 O26 were stx+ . Five of 6 stx+ O26 and O111 produced Stx1, however, stx+ O128 were Stx-negative. Acid resistance (93.3%) and tellurite resistance (87.3%) were common attributes of O157 STEC, whereas, non-O157 stx+ strains exhibited 38.5% and 30.8% of the respective resistances. stx-positive isolates were mostly associated with humans and cattle, whereas, all isolates from mastitis (n = 105), and pigs, dogs, parrot and iguanas (n = 48) were stx-negative. Multiplex PCR was an effective tool for characterizing STEC pathogenic profiles and distinguished STEC O157:H7 from other STEC. Isolates from cattle and human disease shared similar toxigenic profiles, whereas isolates from other disease sources had few characteristics in common with the former isolates. These data suggest interspecies transmissibility of certain serotypes, in particular, STEC O157:H7, between humans and cattle.
Assuntos
Animais Domésticos , Escherichia coli/patogenicidade , Microbiologia de Alimentos , Toxinas Shiga/genética , Fatores de Virulência/análise , Adesinas Bacterianas/genética , Animais , Bovinos , Cães , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Escherichia coli O157/genética , Escherichia coli O157/isolamento & purificação , Escherichia coli O157/patogenicidade , Proteínas de Escherichia coli/biossíntese , Proteínas de Escherichia coli/genética , Genes Bacterianos , Marcadores Genéticos , Proteínas Hemolisinas/biossíntese , Proteínas Hemolisinas/genética , Humanos , Iguanas , Mastite Bovina/microbiologia , Dados de Sequência Molecular , Papagaios , Filogenia , Toxinas Shiga/biossíntese , Suínos , Telúrio/farmacologia , Virulência/genéticaRESUMO
Weaned pigs were separated into eight treatments including a control without exposure to apramycin; a control with exposure to apramycin; and apramycin plus either cold stress, heat stress, overcrowding, intermingling, poor sanitation, or intervention with oxytetracycline, to determine the effects of management and environmental conditions on antibiotic resistance among indigenous Escherichia coli. Pigs exposed to apramycin sulfate received that antibiotic in the feed at a concentration of 150 g/ton for 14 days. Environmental treatments were applied 5 days following initial antibiotic administration and maintained throughout the study. Fecal samples were obtained on day 0 (prior to antibiotic treatment) and on days 2, 7, 14, 28, 64, 148, and 149. E. coli were isolated and tested for resistance to apramycin using a minimum inhibitory concentration (MIC) broth microdilution method. Macrorestriction profiling, arbitrarily primed PCR, PCR targeting a gene coding for apramycin resistance, and DNA hybridization were used to characterize genetic elements of resistance. Increased (P<0.0001) resistance to apramycin was noted in E. coli from all treatment groups administered apramycin. MICs of isolates from control pigs receiving apramycin returned to pretreatment levels following removal of the antibiotic, whereas isolates from cold stress, overcrowding, and oxytetracycline groups expressed greater (P<0.05) MICs through day 64, before returning to pretreatment levels. Genetic analysis indicated that all resistant isolates carried the aac(3)IV gene sequence and this sequence was found in a variety of E. coli isotypes. Our data indicate that E. coli resistance to apramycin is increased upon exposure to various stressors.
Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Nebramicina/análogos & derivados , Nebramicina/farmacologia , Criação de Animais Domésticos/métodos , Animais , Contagem de Colônia Microbiana/veterinária , DNA Bacteriano/análise , Farmacorresistência Bacteriana/genética , Escherichia coli/classificação , Escherichia coli/genética , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Fezes/microbiologia , Testes de Sensibilidade Microbiana/veterinária , Reação em Cadeia da Polimerase/veterinária , Distribuição Aleatória , Suínos , Doenças dos Suínos/tratamento farmacológico , Doenças dos Suínos/microbiologiaRESUMO
OBJECTIVE: To identify the pathogenesis of gastric ulcers by comparing injury to the nonglandular gastric mucosa of horses caused by hydrochloric acid (HCl) or volatile fatty acids (VFAs). SAMPLE POPULATION: Gastric tissues from 30 horses. PROCEDURE: Nonglandular gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference were measured and electrical resistance calculated for tissues after addition of HCl and VFAs to normal Ringer's solution (NRS). Tissues were examined histologically. RESULTS: Mucosa exposed to HCl in NRS (pH, 1.5) had a significant decrease in Isc, compared with Isc for mucosa exposed to NRS at pH 4.0 or 7.0. Also, exposure to 60mM acetic, propionic, and butyric acids (pH, 4.0 or 1.5) caused an immediate significant decrease in Isc. Recovery of sodium transport was detected only in samples exposed to acetic acid at pH 4.0. Recovery of sodium transport was not seen in other mucosal samples exposed to VFAs at pH < or = 4.0. CONCLUSIONS AND CLINICAL RELEVANCE: Acetic, butyric, and propionic acids and, to a lesser extent, HCl caused decreases in mucosal barrier function of the nonglandular portion of the equine stomach. Because of their lipid solubility at pH < or = 4.0, undissociated VFAs penetrate cells in the nonglandular gastric mucosa, which causes acidification of cellular contents, inhibition of sodium transport, and cellular swelling. Results indicate that HCl alone or in combination with VFAs at gastric pH < or = 4.0 may be important in the pathogenesis of gastric ulcers in the nonglandular portion of the stomach of horses.
Assuntos
Ácido Acético/efeitos adversos , Ácido Butírico/efeitos adversos , Doenças dos Cavalos/induzido quimicamente , Ácido Clorídrico/efeitos adversos , Propionatos/efeitos adversos , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/veterinária , Estômago/efeitos dos fármacos , Animais , Técnicas de Cultura , Ácidos Graxos Voláteis/efeitos adversos , Feminino , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/patologia , Doenças dos Cavalos/etiologia , Doenças dos Cavalos/patologia , Cavalos , Concentração de Íons de Hidrogênio , Masculino , Potenciais da Membrana/efeitos dos fármacos , Estômago/patologia , Úlcera Gástrica/etiologia , Úlcera Gástrica/patologia , Fatores de TempoRESUMO
OBJECTIVE: To identify in vitro effects of hydrochloric acid, valeric acid, and other volatile fatty acids (VFAs) on the pathogenesis of ulcers in the nonglandular portion of the equine stomach. SAMPLE POPULATION: Gastric tissues from 13 adult horses. PROCEDURE: Nonglandular gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference were measured and electrical resistance and conductance calculated after tissues were bathed in normal Ringer's solution (NRS) or NRS and hydrochloric, valeric, acetic, propionic, and butyric acids. Treated tissues were examined histologically. RESULTS: Incubation in 60mM valeric acid at pH < or = 7.0 abruptly and irreversibly abolished Isc, which was followed by a slower decrease in resistance and an increase in conductance. Incubation in 60mM acetic, propionic, and butyric acids and, to a lesser extent, hydrochloric acid at pH < or = 7.0 significantly decreased Isc, which was followed by an increase in resistance and a decrease in conductance. CONCLUSIONS AND CLINICAL RELEVANCE: Incubation in valeric acid at pH < or = 7.0 caused a dramatic decrease in mucosal barrier function in the nonglandular portion of the stomach. Changes in barrier function attributable to exposure to valeric acid were associated with histopathologic evidence of cellular swelling in all layers of the nonglandular mucosa. Because of its high lipid solubility, valeric acid penetrates the nonglandular gastric mucosa, resulting in inhibition of sodium transport and cellular swelling. Valeric acid and other VFAs in gastric contents may contribute to the pathogenesis of ulcers in the nonglandular portion of the stomach of horses.