ABSTRACT
OBJETIVO: Analisar a prevalência de anticorpos IgG ao parvovírus humano B19. MÉTODOS: Estudo transversal em uma comunidade de subúrbio de São Paulo, Brasil, de novembro 1990 a janeiro de 1991. Amostras aleatórias (N=435) e representativas de soro foram coletadas de crianças sadias a partir de 15 dias de idade e de adultos com até 40 anos. Os anticorpos IgG ao parvovírus humano B19 foram detectados pelo teste ELISA. RESULTADOS: A prevalência de anticorpos IgG ao parvovírus B19 foi de 87 por cento dos recém-nascidos. A prevalência de anticorpos IgG de origem materna decaiu exponencialmente até o 19o mês de idade. Baixa prevalência de anticorpos foi observada nos primeiros quatro anos de vida, aumentando até 72 por cento no grupo etário de 31-40 anos. A idade média de aquisição da primeira infecção nesta comunidade é de 21 ± 7 anos. A idade ótima para se vacinar as crianças desta comunidade com uma vacina hipotética é de um ano de idade. CONCLUSÕES: A prevalência de anticorpos IgG ao parvovírus B19 foi alta entre recém-nascidos e no grupo etário 31-40 anos. A análise por estrutura etária mostrou padrão similar aos estudos prévios relacionados à baixa prevalência de infecção em crianças que aumenta com a idade.
Subject(s)
Humans , Child , Adult , Seroepidemiologic Studies , Risk Groups , Parvoviridae Infections/epidemiology , Brazil/epidemiologyABSTRACT
OBJECTIVE: To analyze the prevalence of IgG antibodies to human parvovirus B19. METHODS: Cross-sectional study in a suburban community in São Paulo, Southeastern Brazil, between November 1990 and January 1991. Randomly selected (N=435) representative samples of sera were collected from healthy children older than 15 days old and adults up to 40 years old. IgG antibodies were detected using ELISA. RESULTS: High prevalence of IgG antibodies to B19 parvovirus was found in 87% of newborns. The prevalence of maternally derived IgG antibodies exponentially plunged up to the 19th month of age. Low prevalence of antibodies was found in the first 4 years of life, increasing up to 72% in those aged 31-40 years. It was estimated that the average age of first infection in this population is 21 +/- 7 years old and the optimal age for vaccination with a hypothetical vaccine would be 1 year of age. CONCLUSIONS: Parvovirus B19 IgG antibody prevalence was high in newborns and those aged 31-40 years. The analysis by age groups showed a pattern similar to that found in previous studies, i.e., low prevalence of infection in children that increases with age.
Subject(s)
Antibodies, Viral/blood , Immunoglobulin G/blood , Parvoviridae Infections/epidemiology , Parvovirus B19, Human/immunology , Adolescent , Adult , Brazil/epidemiology , Child , Child, Preschool , Enzyme-Linked Immunosorbent Assay , Epidemiologic Methods , Female , Humans , Infant , Male , Parvoviridae Infections/diagnosis , Seroepidemiologic StudiesABSTRACT
UNLABELLED: To study the thermal response of interscapular brown fat (IBF) to norepinephrine (NE), urethan-anesthetized rats (1.2 g/kg ip) maintained at 28-30 degrees C received a constant venous infusion of NE (0-2 x 10(4) pmol/min) over a period of 60 min. IBF temperatures (T(IBF)) were recorded with a small thermistor fixed under the IBF pad. Data were plotted against time and expressed as maximal variation (Deltat degrees C). Saline-injected rats showed a decrease in T(IBF) of approximately 0.6 degrees C. NE infusion increased T(IBF) by a maximum of approximately 3.0 degrees C at a dose of 10(4) pmol x min(-1) x 100 g body wt(-1). Surgically thyroidectomized (Tx) rats kept on 0.05% methimazole showed a flat response to NE. Treatment with thyroxine (T(4), 0.8 microg x 100 g(-1) x day(-1)) for 2-15 days normalized mitochondrial UCP1 (Western blotting) and IBF thermal response to NE, whereas iopanoic acid (5 mg x 100 g body wt(-1) x day(-1)) blocked the effects of T(4). Treatment with 3,5, 3'-triiodothyronine (T(3), 0.6 microg x 100 g body wt(-1) x day(-1)) for up to 15 days did not normalize UCP1 levels. However, these animals showed a normal IBF thermal response to NE. Cold exposure for 5 days or feeding a cafeteria diet for 20 days increased UCP1 levels by approximately 3.5-fold. Nevertheless, the IBF thermal response was only greater than that of controls when maximal doses of NE (2 x 10(4) pmol/min and higher) were used. CONCLUSIONS: 1) hypothyroidism is associated with a blunted IBF thermal response to NE; 2) two- to fourfold changes in mitochondrial UCP1 concentration are not necessarily translated into heat production during NE infusion.
Subject(s)
Adipose Tissue, Brown/metabolism , Body Temperature Regulation/physiology , Carrier Proteins/metabolism , Membrane Proteins/metabolism , Norepinephrine/metabolism , Adipose Tissue, Brown/drug effects , Animals , Body Temperature Regulation/drug effects , Cold Temperature , Diet , Dose-Response Relationship, Drug , Infusions, Intravenous , Ion Channels , Iopanoic Acid/pharmacology , Male , Methimazole/pharmacology , Mitochondria/metabolism , Mitochondrial Proteins , Norepinephrine/administration & dosage , Rats , Rats, Wistar , Thyroidectomy , Thyroxine/antagonists & inhibitors , Thyroxine/blood , Thyroxine/pharmacology , Triiodothyronine/blood , Uncoupling Protein 1ABSTRACT
The contractile action of bradykinin on isolated smooth muscles is known to be potentiated by special peptides isolated from snake venoms and other animal sources. A fraction F (AppF) has been derived from Agkistrodon piscivorus piscivorus venom. This fraction does not increase the depressor effect of bradykinin n blood pressure, potentiates the action of bradykinin on isolated guinea-pig ileum and prolongs the duration of relaxation in isolated rat duodenum. This fraction was able to inhibit the conversion of angiotensin I to angiotensin II in vitro. The primary structure of this decapeptide is given.
Subject(s)
Blood Pressure/drug effects , Crotalid Venoms/chemistry , Muscle, Smooth/drug effects , Oligopeptides/pharmacology , Peptide Fragments/pharmacology , Angiotensin I/metabolism , Angiotensin II/metabolism , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Animals , Bradykinin/metabolism , Bradykinin/pharmacology , Drug Synergism , Guinea Pigs , Mass Spectrometry , Oligopeptides/chemistry , Oligopeptides/isolation & purification , Peptide Fragments/chemistry , Peptide Fragments/isolation & purification , RatsABSTRACT
Peptides that display bradykinin-potentiating activity have been obtained from a number of distinct sources, such as snake venoms, fibrinogen, and casein. This paper describes the isolation and sequencing of a novel bradykinin-potentiating peptide, generated by tryptic hydrolysis of the gamma-casein chain. No homology was found to other known vasoactive or vasopotentiating peptides. The octapeptide Tyr-Pro-Val-Gln-Pro-Phe-Thr-Glu, corresponding to the gamma-casein(114-121) sequence, was isolated from the tryptic hydrolysis of gamma-casein and also synthesized by solid-phase peptide synthesis. Both natural and synthetic peptides had the same retention time in HPLC and displayed a selective potentiating activity on isolated guinea-pig ileum for bradykinin and Lys-bradykinin but were not able to potentiate the effects of Met-Lys-bradykinin, Ile-Ser-bradykinin, angiotensin II, acetylcholine, or histamine. Intravenous injections of bradykinin and of bradykinin-potentiating octapeptide produced a persistent hypotension in conscious rats, a pattern that was not obtained when the octapeptide was replaced by captopril. This bradykinin-potentiating octapeptide is a strong competitive inhibitor of endo-oligopeptidase A (EC 3.4.24.15, formerly EC 3.4.22.19), but it has low inhibitory potency towards angiotensin-converting enzyme (EC 3.4.15.1). Thus, our results suggest that other peptidases in addition to angiotensin-converting enzyme, such as endo-oligopeptidase A, may contribute to the reduction of the effective concentration of bradykinin in the circulation.
Subject(s)
Bradykinin/physiology , Caseins/chemistry , Oligopeptides/pharmacology , Amino Acid Sequence , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Animals , Blood Pressure/drug effects , Caseins/pharmacology , Chromatography, Gel , Chromatography, High Pressure Liquid , Female , Guinea Pigs , Hydrolysis , In Vitro Techniques , Molecular Sequence Data , Muscle Contraction/drug effects , Oligopeptides/chemistry , Oligopeptides/isolation & purification , Protein Hydrolysates/chemistry , Protein Hydrolysates/pharmacology , Rats , Trypsin , Uterine Contraction/drug effectsABSTRACT
1. We evaluated the involvement of circulating kinins in the hypotensive effect of the antihypertensive drug alpha-methyldopa (alpha-MD) in normotensive rats. 2. The alpha-MD effects were more pronounced in urethane-anesthetized rats than in unanesthetized animals. 3. Treatment with alpha-MD did not affect the circulating levels of kininogen, the bradykinin precursor. 4. Pretreatment with captopril that potentiates the depressor effects of bradykinin did not potentiate the hypotension to alpha-MD. 5. The lack of changes in kininogen levels and the failure of captopril to potentiate the depressor effects of alpha-MD rules out an involvement of the circulating kallikrein-kinin system in the response to alpha-MD.
Subject(s)
Blood Pressure/drug effects , Kallikreins/physiology , Kinins/physiology , Methyldopa/pharmacology , Animals , Bradykinin/pharmacology , Captopril/pharmacology , Chromatography, High Pressure Liquid , Guinea Pigs , Kininogens/blood , Male , Rats , Rats, WistarABSTRACT
The effects of icv administration of ß-endorphin on secretory activity of dopaminergic neurons is described. Homovanillic and dihydroxyphenyl acetic acid levels in cerebrospinal fluid and extracts of brain tissue were determined after administration of ß-endorphin to animals pretreated or not with saloxone. The results suggest that ß-endorphin interferes with formation of dopaminergic metabolites by acting on opioid receptors
Subject(s)
Rats , Animals , 3,4-Dihydroxyphenylacetic Acid/cerebrospinal fluid , beta-Endorphin/physiology , Corpus Striatum/metabolism , Homovanillic Acid/cerebrospinal fluid , Substantia Nigra/metabolism , Dopamine/metabolism , Naloxone/therapeutic use , Neurons/physiologyABSTRACT
The effects of icv administration of beta-endorphin on secretory activity of dopaminergic neurons is described. Homovanillic and dihydroxyphenyl acetic acid levels in cerebrospinal fluid and extracts of brain tissue were determined after administration of beta-endorphin to animals pretreated or not with naloxone. The results suggest that beta-endorphin interferes with formation of dopaminergic metabolites by acting on opioid receptors.
