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1.
Access Microbiol ; 2(8): acmi000137, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32974599

RESUMO

Clostridium ramosum is an enteric anaerobic, endospore-forming, gram-positive rod with a low GC content that is rarely associated with disease in humans. We present a case of C. ramosum bacteraemia. To the best of our knowledge, this is the second case of C. ramosum bacteraemia in an elderly patient presenting with fever, abdominal pain and bilious emesis. We highlight the Gram stain variability, the lack of visualization of spores and the atypical morphology of the colonies that showed C. ramosum in a polymicrobial presentation that initially appeared to show monomicrobial bacteraemia. The microorganism was rapidly identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We present a comprehensive literature review of 32 cases of clinical infections by C. ramosum in which we describe, if available, sex, age, clinical symptoms, predisposing conditions, other organisms present in the blood culture, other samples with C. ramosum , identification methodology, treatment and outcome.

2.
Anim Genet ; 51(1): 78-86, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31802524

RESUMO

In the past two decades, average litter size (ALS) in Entlebucher Mountain dogs decreased by approximately 0.8 puppies. We conducted a GWAS for ALS using the single-step methodology to take advantage of 1632 pedigree records, 892 phenotypes and 372 genotypes (173 662 markers) for which only 12% of the dogs had both phenotypes and genotypes available. Our analysis revealed associations towards the growth differentiation factor 9 gene (GDF9), which is known to regulate oocyte maturation. The trait heritability was estimated at 43.1%, from which approximately 15% was accountable by the GDF9 locus alone. Therefore, markers flanking GDF9 explained approximately 6.5% of the variance in ALS. Analysis of WGSs revealed two missense substitutions in GDF9, one of which (g.11:21147009G>A) affected a highly conserved nucleotide in vertebrates. The derived allele A was validated in 111 dogs and shown to be associated with decreased ALS (-0.75 ± 0.22 puppies per litter). The variant was further predicted to cause a proline to serine substitution. The affected residue was immediately followed by a six-residue deletion that is fixed in the canine species but absent in non-canids. We further confirmed that the deletion is prevalent in the Canidae family by sequencing three species of wild canids. Since canids uniquely ovulate oocytes at the prophase stage of the first meiotic division, requiring maturation in the oviduct, we conjecture that the amino acid substitution and the six-residue deletion of GDF9 may serve as a model for insights into the dynamics of oocyte maturation in canids.


Assuntos
Cães/genética , Fator 9 de Diferenciação de Crescimento/genética , Tamanho da Ninhada de Vivíparos/genética , Mutação de Sentido Incorreto , Sequência de Aminoácidos , Animais , Cruzamento , Feminino , Estudos de Associação Genética/veterinária , Genótipo , Masculino , Linhagem , Fenótipo
3.
Neuroscience ; 281: 44-53, 2014 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-25255933

RESUMO

Scheduled and restricted access to a palatable snack, i.e. chocolate, elicits a brief and strong anticipatory activation and entrains brain areas related with reward and motivation. This behavioral and neuronal activation persists for more than 7days when this protocol is interrupted, suggesting the participation of a time-keeping system. The process that initiates this anticipation may provide a further understanding of the time-keeping system underlying palatable food entrainment. The aim of this study was to analyze how this entraining protocol starts and to dissect neuronal structures that initiate a chocolate-entrained activation. We assessed the development of anticipation of 5g of chocolate during the first 8days of the entrainment protocol. General activity of control and chocolate-entrained rats was continuously monitored with movement sensors. Moreover, motivation to obtain the chocolate was assessed by measuring approaches and interaction responses toward a wire-mesh box containing chocolate. Neuronal activation was determined with c-Fos in reward-related brain areas. We report a progressive increase in the interaction with a box to obtain chocolate parallel to a progressive neuronal activation. A significant anticipatory activation was observed in the prefrontal cortex on day 3 of entrainment and in the nucleus accumbens on day 5, while the arcuate nucleus and pyriform cortex reached significant activation on day 8. The gradual response observed with this protocol indicates that anticipation of a rewarding food requires repetitive and predictable experiences in order to acquire a temporal estimation. We also confirm that anticipation of palatable food involves diverse brain regions.


Assuntos
Antecipação Psicológica/fisiologia , Núcleo Arqueado do Hipotálamo/metabolismo , Comportamento Animal/fisiologia , Comportamento Alimentar/fisiologia , Núcleo Accumbens/metabolismo , Córtex Piriforme/metabolismo , Córtex Pré-Frontal/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Recompensa , Animais , Chocolate , Ritmo Circadiano/fisiologia , Masculino , Ratos , Ratos Wistar , Fatores de Tempo
4.
Arq. bras. med. vet. zootec ; 66(1): 161-167, fev. 2014. ilus, tab
Artigo em Português | LILACS | ID: lil-704020

RESUMO

Chlamydophila psittaci é uma bactéria que causa doença respiratória ou sistêmica em aves e em seres humanos. Em vista do risco de transmissão para humanos, o objetivo deste estudo foi detectar a presença de Chlamydophila spp. em amostras de fezes ou suabes cloacais de aves assintomáticas. Foram colhidas 403 amostras fecais ou suabes cloacais, provenientes de aves domésticas, selvagens ou exóticas. As amostras foram submetidas à PCR em tempo real para C. psittaci, para amplificação de fragmento parcial do gene da subunidade 16S do rRNA, utilizando o SsoFastTM EvaGreen® Supermix (Bio-Rad) e análise da curva de dissociação. Para determinação do genótipo de C. psittaci, foi usada a hemi-nested PCR visando à amplificação de fragmento parcial do gene OMP-A, realizada nas amostras positivas pela PCR em tempo real, seguida de sequenciamento dos fragmentos amplificados. A PCR em tempo real revelou positividade em 17 (4,21%) amostras. A hemi-nested foi positiva em 2 amostras positivas pela PCR em tempo real. O genótipo A de C. psittaci foi identificado pelo sequenciamento de uma amostra amplificada pela hemi-nested PCR. Os resultados deste experimento demonstram que a PCR em tempo real, visando à amplificação de fragmento parcial da subunidade 16S do rRNA, seguida da análise da curva de dissociação, pode ser utilizada para detecção de DNA de Chlamydophila sp. em amostras fecais de aves assintomáticas. A classificação da espécie de Chlamydophila e do genótipo de C. psittaci deve ser realizada por meio de PCR tendo como alvo o gene ompA e sequenciamento dos fragmentos amplificados.


Chlamydophila psittaci is a bacterium that causes respiratory or systemic disease in birds and humans. Owing to the risk of transmission from asymptomatic birds to humans, the objective of this study was to detect the presence of Chlamydophila spp. in asymptomatic birds. Four hundred and three fecal samples or cloacal swabs were collected from domestic, wild or exotic birds. The 403 samples were examined by real time PCR specific for the 16S subunit of rRNA gene using SsoFastEvaGreen®SupermixTM (Bio-Rad) and melting curve analysis. Hemi-nested PCR specific for the OMP-A gene, accomplished in real-time PCR positive samples, was followed by sequencing of the amplified fragments to determine the genotype of C. psittaci. Real-time PCR was positive in 17 (4.21%) samples. Hemi-nested PCR revealed positivity in two samples previously positive by real-time PCR. Sequencing of the fragment amplified by hemi-nested PCR allowed for the identification of genotype A of C. psittaci in one sample. The results of this experiment show that the real-time PCR targeting the 16S rRNA gene followed by melting curve analysis can be used for diagnosis of Chlamydophila sp. in fecal samples of asymptomatic birds. The classification of the Chlamydophila species and the genotype of C. psittaci must be accomplished by PCR targeting the ompA gene and sequencing of the amplified fragments.


Assuntos
Animais , Bactérias , Chlamydophila , Fezes , Guano australis/análise , Psitacose/patologia , Aves/classificação
5.
Arq. bras. med. vet. zootec ; 62(4): 816-820, Aug. 2010. ilus
Artigo em Português | LILACS | ID: lil-562047

RESUMO

Relata-se um caso de ceratoconjuntivite causada por Encephalitozoon hellem em agapornis (Agapornis spp.) adultos, provenientes de um criatório comercial. Cinco animais apresentaram sinais clínicos de ceratoconjuntivite, blefaroespasmo e blefaroedema bilateral, com presença de secreção seropurulenta. Amostras fecais foram colhidas e foi realizado exame coproparasitológico, com resultado negativo. Dois animais foram necropsiados, sendo detectados, em impressões de raspado de conjuntiva ocular, esporos e outros estádios evolutivos de Microsporidium. A confirmação do diagnóstico foi feita pela reação em cadeia de polimerase e sequenciamento de fragmentos amplificados, com utilização de primers específicos para o gene da subunidade 18S do rRNA de E. hellem. A análise dos fragmentos amplificados demonstrou 100 por cento de similaridade com outras sequências de E. hellem publicadas no GenBank. Este é primeiro relato de infecção por E. hellem em aves no Brasil.


A clinical case of keratoconjunctivitis by Encephalitozoon hellem in adult lovebirds (Agapornis spp.) from a commercial flock is reported. Five animals presented clinical symptoms of keratoconjunctivitis, blepharospasm, and bilateral blepharoedema, with seropurulent secretion. Coproparasitological diagnosis was carried out in fecal samples, with negative results. Two animals were necropsied, with detection of spores and other developmental stages of Microsporidium in conjunctival smears. The confirmation of the diagnosis was accomplished by the polimerase chain reaction with specific primers for 18S subunit of the rRNA of E. hellem, followed by sequencing of amplified fragments, which revealed 100 percent of genetic similarity to E. hellem. This study is the first report of E. hellem infection in birds in Brazil.


Assuntos
Animais , Ceratoconjuntivite/diagnóstico , Ceratoconjuntivite/veterinária , Encephalitozoon/isolamento & purificação , Periquitos , Zoonoses
6.
J Clin Microbiol ; 44(10): 3634-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17021092

RESUMO

The Clinical and Laboratory Standards Institute (CLSI) proposed, beginning in 2004, the use of cefoxitin disks to predict resistance mediated by the mecA gene in all species of coagulase-negative staphylococci (CoNS). The aim of this work was to evaluate the efficiency of the cefoxitin disk and of oxacillin-salt agar screening (MHOX) to characterize the oxacillin resistance mediated by the mecA gene in CoNS. One hundred seven CoNS isolates from different clinical samples were studied. Detection of the mecA gene by PCR was considered the "gold standard." The susceptibility to oxacillin and cefoxitin was detected by the disk diffusion and agar dilution tests, as described by the CLSI. MHOX was also performed with 6 microg/ml of oxacillin and 4% NaCl. The sensitivities of the oxacillin and cefoxitin disks for all CoNS species were 88% and 80%, respectively, whereas the specificities were 63% and 100%, respectively. The sensitivities of the agar dilution test for oxacillin and cefoxitin (for proposed breakpoints of > or =4 microg/ml for resistance and < or =2 microg/ml for susceptibility) were 90% and 85%, respectively, whereas the specificities were 76% and 98%, respectively. MHOX showed a sensitivity of 90% and a specificity of 95% for all CoNS species. Both the MHOX and the cefoxitin disk results indicate that these are appropriate methods for the evaluation of oxacillin resistance mediated by the mecA gene in all CoNS species.


Assuntos
Técnicas de Tipagem Bacteriana/métodos , Cefoxitina/farmacologia , Oxacilina/farmacologia , Resistência às Penicilinas , Proteínas de Ligação às Penicilinas/metabolismo , Staphylococcus/efeitos dos fármacos , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Staphylococcus/metabolismo
7.
Rev Argent Microbiol ; 38(1): 9-12, 2006.
Artigo em Espanhol | MEDLINE | ID: mdl-16784126

RESUMO

Pregnant women are more susceptible to both vaginal colonization and infection by yeast. Our objectives were to determine the prevalence in pregnant women of yeasts isolated from vaginal exudates and their susceptibility to current antifungal drugs. A total of 493 patients was studied between December 1998 and February 2000. The prevalence of Candida spp. was 28% (Candida albicans 90.4%; Candida glabrata 6.3%; Candida parapsilosis 1.1%, Candida kefyr 1.1 %; unidentified species 1.1 %). The diffusion test in Shadomy agar was employed to determine the susceptibility to fluconazole, ketoconazole, itraconazole and nistatine. All C. albicans, C. kefyr and C. parapsilosis isolates were susceptible in vitro to the antifungal agents tested, while 1 in 6 C. glabrata isolates showed resistance to azole drugs; all strains were susceptible to nistatine. In pregnant women, C. albicans was the yeast most frequently isolated from vaginal exudates; it continues to be highly susceptible to antifungal drugs. Azole resistance was detected only among C. glabrata isolates. Identification to the species level is recommended, specially in cases of treatment failure and recurrent or chronic infection.


Assuntos
Candida/isolamento & purificação , Candidíase Vulvovaginal/epidemiologia , Complicações Infecciosas na Gravidez/epidemiologia , Adolescente , Adulto , Antifúngicos/farmacologia , Argentina/epidemiologia , Candida/classificação , Candida/efeitos dos fármacos , Candidíase Vulvovaginal/microbiologia , Farmacorresistência Fúngica , Feminino , Humanos , Gravidez , Complicações Infecciosas na Gravidez/microbiologia , Prevalência , Especificidade da Espécie
8.
Rev. argent. microbiol ; 38(1): 9-12, ene.-mar. 2006. tab
Artigo em Espanhol | LILACS | ID: lil-634512

RESUMO

La mujer embarazada es más susceptible tanto a la colonización como a la infección vaginal por levaduras. El objetivo de este trabajo fue determinar la prevalencia de levaduras aisladas de exudados vaginales de mujeres embarazadas y evaluar la sensibilidad a los antifúngicos de uso frecuente. Se estudiaron 493 pacientes en el período comprendido desde diciembre de 1998 hasta febrero de 2000. La prevalencia de Candida spp. fue 28% (Candida albicans 90,4%, Candida glabrata 6,3%, Candida parapsilosis 1,1%, Candida kefyr 1,1%, especies no identificadas 1,1%). Se determinó la sensibilidad a fluconazol, ketoconazol, itraconazol y nistatina por el método de difusión en agar Shadomy. Todos los aislamientos de C. albicans, C. kefyr y C. parapsilosis fueron sensibles in vitro a los antifúngicos probados, mientras que 1 de 6 aislamientos de C. glabrata presentó resistencia extendida a todos los azoles, pero sensibilidad a nistatina. En mujeres embarazadas C. albicans fue la levadura más frecuentemente aislada de exudados vaginales y continúa siendo ampliamente sensible a los antifúngicos; sólo en C. glabrata se observó resistencia a los azoles. Se recomienda la identificación de la levadura a nivel de especie particularmente en el caso de falla terapéutica y en infecciones recidivantes o crónicas.


Pregnant women are more susceptible to both vaginal colonization and infection by yeast. Our objectives were to determine the prevalence in pregnant women of yeasts isolated from vaginal exudates and their susceptibility to current antifungal drugs. A total of 493 patients was studied between December 1998 and February 2000. The prevalence of Candida spp. was 28% (Candida albicans 90.4%; Candida glabrata 6.3%; Candida parapsilosis 1.1%, Candida kefyr 1.1%; unidentified species 1.1%). The diffusion test in Shadomy agar was employed to determine the susceptibility to fluconazole, ketoconazole, itraconazole and nistatine. All C. albicans, C. kefyr and C. parapsilosis isolates were susceptible in vitro to the antifungal agents tested, while 1 in 6 C. glabrata isolates showed resistance to azole drugs; all strains were susceptible to nistatine. In pregnant women, C. albicans was the yeast most frequently isolated from vaginal exudates; it continues to be highly susceptible to antifungal drugs. Azole resistance was detected only among C. glabrata isolates. Identification to the species level is recommended, specially in cases of treatment failure and recurrent or chronic infection.


Assuntos
Adolescente , Adulto , Feminino , Humanos , Gravidez , Candida/isolamento & purificação , Candidíase Vulvovaginal/epidemiologia , Complicações Infecciosas na Gravidez/epidemiologia , Antifúngicos/farmacologia , Argentina/epidemiologia , Candida/classificação , Candida/efeitos dos fármacos , Candidíase Vulvovaginal/microbiologia , Farmacorresistência Fúngica , Prevalência , Complicações Infecciosas na Gravidez/microbiologia , Especificidade da Espécie
9.
Rev Argent Microbiol ; 36(2): 78-80, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15470866

RESUMO

We describe four isolates of Ng from men who have sex with men (MSM) patients that were able to grow in the abscense of CO2, as previously was described for N. gonorrhoeae ssp. kochii. These isolates were able to grow aerobically (without any added CO2) at 37 degrees C giving small colonies after 48 hs; two of them isolated from pharynx and urethra of one patient, were also able to grow without the blood supplement in the same conditions. In these unusual isolates the major outer-membrane proteins are of the same molecular weight than Ng. These isolates could be taken for other members of the genus if not confirmed by means of these (or other) methods.


Assuntos
Neisseria gonorrhoeae/classificação , Neisseria gonorrhoeae/crescimento & desenvolvimento , Bactérias Aeróbias , Proteínas da Membrana Bacteriana Externa , Dióxido de Carbono , Meios de Cultura , Gonorreia/microbiologia , Homossexualidade Masculina , Humanos , Masculino , Neisseria gonorrhoeae/isolamento & purificação , Fenótipo
10.
Rev. argent. microbiol ; 36(2): 78-80, abr.-jun. 2004.
Artigo em Espanhol | LILACS-Express | LILACS, BINACIS | ID: biblio-1171746

RESUMO

We describe four isolates of Ng from men who have sex with men (MSM) patients that were able to grow in the abscense of CO2, as previously was described for N. gonorrhoeae ssp. kochii. These isolates were able to grow aerobically (without any added CO2) at 37 degrees C giving small colonies after 48 hs; two of them isolated from pharynx and urethra of one patient, were also able to grow without the blood supplement in the same conditions. In these unusual isolates the major outer-membrane proteins are of the same molecular weight than Ng. These isolates could be taken for other members of the genus if not confirmed by means of these (or other) methods.

11.
Rev. argent. microbiol ; 36(2): 78-80, 2004 Apr-Jun.
Artigo em Inglês | BINACIS | ID: bin-38615

RESUMO

We describe four isolates of Ng from men who have sex with men (MSM) patients that were able to grow in the abscense of CO2, as previously was described for N. gonorrhoeae ssp. kochii. These isolates were able to grow aerobically (without any added CO2) at 37 degrees C giving small colonies after 48 hs; two of them isolated from pharynx and urethra of one patient, were also able to grow without the blood supplement in the same conditions. In these unusual isolates the major outer-membrane proteins are of the same molecular weight than Ng. These isolates could be taken for other members of the genus if not confirmed by means of these (or other) methods.

12.
Rev Argent Microbiol ; 35(4): 183-7, 2003.
Artigo em Espanhol | MEDLINE | ID: mdl-14976869

RESUMO

Streptococcus agalactiae--group B streptococci (GBS)--is a main cause of severe neonatal infections with a high mortality rate. The detection of pregnant GBS carriers (5-35%) allows intrapartum administration of antibiotic prophylaxis to these women and prevents perinatal infection. We studied the prevalence of GBS in 259 patients between 28 and 37 weeks gestation from April 2000 to March 2002. The anorectum (AR) and vaginal introitus swabs (VI) were cultured in selective Todd-Hewitt broth containing colistin (10 micrograms/ml) and nalidixic acid (15 micrograms/ml) while vaginal swabs (VFS) were cultured following conventional methods. A total of 47 strains of EGB were isolated from 259 patients (18.15%). The prevalence in different samples were: 5.40% in VFS, 13.51% in VI, 11.58% in AR and 17.76% in VI + AR (reference method). The isolates were tested against penicillin, ceftriaxone, erythromycin, clindamycin, vancomycin, gentamicin and streptomycin to determine the minimum inhibitory concentration. The resistance phenotypes of erythromycin-resistant GBS were determined by the double-disk test. All strains were susceptible to penicillin, ceftriaxone and vancomycin, only one strain was erythromycin and clindamycin resistant by IMLSB mechanism. None of the isolated strains had a high resistant level to aminoglycosides. The sensitivity of cultures increased when selective broths were used as the primary detection method.


Assuntos
Portador Sadio/epidemiologia , Complicações Infecciosas na Gravidez/epidemiologia , Infecções Estreptocócicas/epidemiologia , Streptococcus agalactiae/isolamento & purificação , Vaginose Bacteriana/epidemiologia , Adolescente , Adulto , Canal Anal/microbiologia , Argentina/epidemiologia , Portador Sadio/microbiologia , Meios de Cultura , Resistência a Medicamentos , Feminino , Humanos , Testes de Sensibilidade Microbiana/métodos , Gravidez , Complicações Infecciosas na Gravidez/microbiologia , Terceiro Trimestre da Gravidez , Prevalência , Reto/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae/classificação , Streptococcus agalactiae/efeitos dos fármacos , Vaginose Bacteriana/microbiologia
13.
Rev. argent. microbiol ; 35(4): 183-7, 2003 Oct-Dec.
Artigo em Espanhol | BINACIS | ID: bin-38764

RESUMO

Streptococcus agalactiae--group B streptococci (GBS)--is a main cause of severe neonatal infections with a high mortality rate. The detection of pregnant GBS carriers (5-35


) allows intrapartum administration of antibiotic prophylaxis to these women and prevents perinatal infection. We studied the prevalence of GBS in 259 patients between 28 and 37 weeks gestation from April 2000 to March 2002. The anorectum (AR) and vaginal introitus swabs (VI) were cultured in selective Todd-Hewitt broth containing colistin (10 micrograms/ml) and nalidixic acid (15 micrograms/ml) while vaginal swabs (VFS) were cultured following conventional methods. A total of 47 strains of EGB were isolated from 259 patients (18.15


). The prevalence in different samples were: 5.40


in VFS, 13.51


in VI, 11.58


in AR and 17.76


in VI + AR (reference method). The isolates were tested against penicillin, ceftriaxone, erythromycin, clindamycin, vancomycin, gentamicin and streptomycin to determine the minimum inhibitory concentration. The resistance phenotypes of erythromycin-resistant GBS were determined by the double-disk test. All strains were susceptible to penicillin, ceftriaxone and vancomycin, only one strain was erythromycin and clindamycin resistant by IMLSB mechanism. None of the isolated strains had a high resistant level to aminoglycosides. The sensitivity of cultures increased when selective broths were used as the primary detection method.

14.
Rev. argent. microbiol ; 35(4): 183-7, 2003 Oct-Dec.
Artigo em Espanhol | LILACS-Express | LILACS, BINACIS | ID: biblio-1171737

RESUMO

Streptococcus agalactiae--group B streptococci (GBS)--is a main cause of severe neonatal infections with a high mortality rate. The detection of pregnant GBS carriers (5-35


) allows intrapartum administration of antibiotic prophylaxis to these women and prevents perinatal infection. We studied the prevalence of GBS in 259 patients between 28 and 37 weeks gestation from April 2000 to March 2002. The anorectum (AR) and vaginal introitus swabs (VI) were cultured in selective Todd-Hewitt broth containing colistin (10 micrograms/ml) and nalidixic acid (15 micrograms/ml) while vaginal swabs (VFS) were cultured following conventional methods. A total of 47 strains of EGB were isolated from 259 patients (18.15


). The prevalence in different samples were: 5.40


in AR and 17.76


in VI + AR (reference method). The isolates were tested against penicillin, ceftriaxone, erythromycin, clindamycin, vancomycin, gentamicin and streptomycin to determine the minimum inhibitory concentration. The resistance phenotypes of erythromycin-resistant GBS were determined by the double-disk test. All strains were susceptible to penicillin, ceftriaxone and vancomycin, only one strain was erythromycin and clindamycin resistant by IMLSB mechanism. None of the isolated strains had a high resistant level to aminoglycosides. The sensitivity of cultures increased when selective broths were used as the primary detection method.

17.
J Clin Invest ; 57(1): 230-43, 1976 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-173741

RESUMO

The purpose of the present study was to investigate the regulation of insulin biosynthesis during the perinatal period. The incorporation of [3H]leucine into total immunoreactive insulin (IRI) and into IRI fractions was measured by a specific immunoprecipitation procedure after incubation, extraction, and gel filtration in isolated 3-day-old rat pancreases without prior isolation of islets. IRI fractions were identified by their elution profile, their immunological properties, and their ability to compete with the binding of 125 I-insulin in rat liver plasma membranes. No specific incorporation of [3H]leucine was found in the IRI eluted in the void volume, making it unlikely that this fraction behaves as a precursor of (pro) insulin in this system. In all conditions tested, the incorporation of [3H]leucine was linearly correlated with time. Optimal concentration of glucose (11 mM) activated six- to sevenfold the [3H]leucine incorporation into IRI. Theophylline or N6O2-dibutyryl- (db) cAMP at 1.6 mM glucose significantly increased the [3H]leucine incorporation. Glucose at 16.7 mM further enhanced the effect of both drugs. Contrarily, somatostatin (1-10 mug/ml) inhibits the rate of [3H]leucine incorporation into IRI in the presence of 11 mM glucose; this effect was observed at 5.5 mM glucose and was not modified by any further increase in glucose concentrations up to 27.5 mM. Theophylline or dbcAMP at 10 mM concentration did not reverse the somatostatin inhibitory effect on either insulin biosynthesis or release. Somatostatin also inhibited both processes in isolated islets from the 3-day-old rat pancreas. High Ca++ concentration in the incubation medium reversed the inhibitory effect of somatostatin on glucose-induced insulin biosynthesis as well as release. In both systems the inhibitory effect of somatostatin on insulin biosynthesis and release correlated well. Glipizide (10-100 muM) AND TOLBUTAMIDE (400 MUM) inhibited the stimulatory effect of glucose, dbcAMP, and theophylline on [3H]leucine incorporation into IRI. The concentrations of glipizide that were effective in inhibiting [3H]leucine incorporation into IRI were smaller than those required to inhibit the phosphodiesterase activity in isolated islets of 3-day-old rat pancreas. These data suggest the following conclusions: (a) the role of the cAMP-phosphodiesterase system on insulin biosynthesis is likely to be greater in newborns than in adults; (b) the greater effectiveness of glucose and the cAMP system on insulin biosynthesis than on insulin release might possibly be related to the rapid accumulation of pancreatic IRI which is observed in the perinatal period; (c) somatostatin, by direct interaction with the endocrine tissue, can inhibit glucose and cAMP-induced insulin biosynthesis as well as release; calcium reverses this inhibition; (d) sulfonylureas inhibit insulin biosynthesis in newborn rat pancreas an effect which has to be considered in the use of these agents in human disease.


Assuntos
Animais Recém-Nascidos/metabolismo , AMP Cíclico/farmacologia , Glucose/farmacologia , Insulina/biossíntese , Ilhotas Pancreáticas/metabolismo , Proinsulina/biossíntese , Somatostatina/farmacologia , Compostos de Sulfonilureia/farmacologia , Animais , Antígenos , Glipizida/farmacologia , Humanos , Ilhotas Pancreáticas/efeitos dos fármacos , Leucina/metabolismo , Ratos , Teofilina/farmacologia , Tolbutamida/farmacologia
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