RESUMO
The aim of this study is to explore the pathogenesis of granulomatous lobular mastitis (GLM) via pathology and molecular biology. This single-center study included 28 female patients who received a diagnosis of pathologically confirmed GLM from January 2020 to September 2020 at Dongzhimen Hospital of Beijing University of Chinese Medicine. Tissue samples and serum were collected during radical surgery. Western blot and immunohistochemistry were employed to determine caspase-1 and gasdermin D (GSDMD). Transmission electron microscopy (TEM) was used to observe the ultrastructure of cells. Finally, the results were analyzed. The expression of activated GSDMD and caspase-1 were all increased in the lesion group (P < 0.05). The TEM results showed clear features of pyroptosis. We concluded that pyroptosis was important in the development of GLM and inhibitad apoptosis to some degree. The inhibition of pyroptosis response may help to discover new drugs for GLM.
Assuntos
Mastite , Piroptose , Apoptose , Feminino , HumanosRESUMO
Objective: To analyze the epidemiological characteristics and spatiotemporal distribution of hemorrhagic fever with renal syndrome (HFRS) in Zhejiang province from 2005 to 2020, and provide scientific information for the precise prevention and control of HFRS. Methods: Data on HFRS cases in Zhejiang province during 2005-2020 were collected from the China National Notifiable Infectious Disease Reporting Information System (NNDS) for a descriptive analysis, and software ArcGIS 10.2 was used for global autocorrelation and local autocorrelation analyses. Spatiotemporal clusters were scanned with SaTScan 9.4.4 and visualized with ArcGIS 10.2. Results: A total of 7 724 HFRS cases were reported in Zhejiang province from 2005 to 2020, including 25 deaths. There were two incidence peaks each year, in late spring and early summer (May-June) and in winter (November-January). The top three areas with high cumulative cases were Ningbo (1 875, 24.27%), Taizhou (1 642, 21.25%), and Shaoxing (1 123, 14.54%). Among the reported cases, with a male to female ratio of 2.73â¶1(5 656â¶2 068). The majority of HFRS cases were middle-aged and elderly people, with cases aged 41-70 years accounting for 60.95%. Most HFRS cases were farmers, accounting for 69.89% (5 398/7 724). The spatial distribution of HFRS in most years was correlated. SaTScan was used for retrospective spatiotemporal scanning and three clusters were detected: the first type clusters were in 21 counties in eastern Zhejiang province and central Zhejiang province, among which 4 were in Ningbo, Shaoxing and Jinhua, 8 were in Taizhou, and 1 was in Lishui (RR=13.69, LLR=5 522.60, P<0.001); the second type clusters were in Longquan and Qingyuan counties (RR=31.20, LLR=1 232.46, P<0.001); the third types of clusters were in Changxing and Anji counties of Huzhou in northern Zhejiang province (RR=3.42, LLR=23.93, P<0.001). Conclusions: HFRS mainly occurred in middle-aged,elderly and male farmers in Zhejiang province. The incidence was high in late spring, early summer and winter in eastern Zhejiang province. Precise prevention and control measures are needed for populations at high risk before the epidemic season.
Assuntos
Epidemias , Febre Hemorrágica com Síndrome Renal , Idoso , China/epidemiologia , Notificação de Doenças , Feminino , Febre Hemorrágica com Síndrome Renal/epidemiologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
Brucellosis is an occupational disease affecting workers in butcher shops, the milking and dairy product industry, causing more than 500 000 new cases around the world. As a national statutory B infectious disease in China, morbidity of brucellosis is rapidly increasing in recent years. We report an occupational outbreak of brucellosis infection in a pharmaceutical factory. Exposure was a result of manual operation in the process line, close contact with sheep placentas, insufficient disinfection and repeated using of protective suits and infected by aerosol dissemination. Improved preventive methods, appropriate public health measures and spread of health education would be helpful to prevent the occupational outbreak of brucellosis in future.
Assuntos
Brucelose/epidemiologia , Brucelose/etiologia , Surtos de Doenças , Indústria Farmacêutica , Exposição Ocupacional , Estudos de Casos e Controles , China/epidemiologia , Humanos , Roupa de Proteção , Fatores de RiscoRESUMO
OBJECTIVE: To evaluate the clinical efficacy of anterior debridement combined with posterior atlantoaxial fusion for atlantoaxial Tuberculosis. METHODS: From February 2005 to February 2013, 7 patients, 3 males and 4 females, with atlantoaxial Tuberculosis underwent anterior debridement combined with posterior atlantoaxial fusion in Department of Orthopedics Zhengzhou University People's Hospital were selected.In the preoperative and final follow-up, Japanese Orthopaedic Association score (JOA), neck disability index (NDI) and Frankel Classification were used to evaluate neurological function and calculate improvement rate.At final follow-up, clinical efficacy was evaluated by Odom's grade.Situation of internal fixation, fusion of upper cervical were assessed by X-ray, CT scan and MRI scan. RESULTS: Bony fusion were achieved in 7 cases after operation in 12 months. Tuberculosis were reached clinical cure between 17 and 21 months. At follow The JOA score increased from (11.1±0.7) preoperatively to (15.3±0.5) in final follow-up(P<0.05), and the NDI decreased from (34.0±4.6) preoperatively to (10.1±1.3) in final follow-up (P<0.05). At last follow-up, according to Odom's standard, excellent were obtained in 5 cases, good 1 cases and ordinary 1 case. Frankel Classification of all cases improved from D class to E. CONCLUSIONS: The treatment of anterior retropharyngeal debridement combine with atlantoaxial fusion, and local anti-tuberculosis drug using intraoperative, not only could obtain reliable clinical efficacy, completly removal of lesions, but also obtain strong stability, which plays an important role in the treatment of atlantoaxial Tuberculosis.
Assuntos
Articulação Atlantoaxial/anormalidades , Anormalidades Congênitas , Desbridamento , Fusão Vertebral/métodos , Vértebras Torácicas/cirurgia , Tuberculose da Coluna Vertebral/cirurgia , Artrodese , Feminino , Fixação Interna de Fraturas , Humanos , Fixadores Internos , Imageamento por Ressonância Magnética , Masculino , Período Pós-Operatório , Procedimentos de Cirurgia Plástica , Vértebras Torácicas/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Tuberculose da Coluna Vertebral/diagnóstico por imagemRESUMO
Gout is the most common form of inflammatory arthritis affecting men, and current evidence suggests that genetic factors contribute to its progression. As a previous study identified that WD40 repeat protein 1 (WDR1) is associated with gout in populations of European descent, we sought to investigate its relationship with this disease in the Han Chinese population. We genotyped six WDR1 single nucleotide polymorphisms in 143 gout cases and 310 controls using Sequenom MassARRAY technology. The SPSS 16.0 software was used to perform statistical analyses. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression, with adjustments for age and gender. In an analysis using an allelic model, we identified that the minor alleles of rs3756230 (OR = 0.64, 95%CI = 0.450-0.911, P = 0.013) and rs12498927 (OR = 1.377, 95%CI = 1.037-1.831, P = 0.027) were associated with gout risk. In addition, we found that the "A/A" genotype of rs12498927 was associated with increased risk of gout under codominant (OR = 2.22, 95%CI = 1.12- 4.40, P = 0.042) and recessive models (OR = 2.24, 95%CI = 1.20-4.17, P = 0.012). We also determined the "A/G" genotype of rs12498927 to be significantly associated with higher urea levels in gout patients (P = 0.017). Our data shed new light on the association between genetic variations in the WDR1 gene and gout susceptibility in the Han Chinese population.
Assuntos
Gota/genética , Proteínas dos Microfilamentos/genética , Polimorfismo de Nucleotídeo Único , Adulto , Estudos de Casos e Controles , China , Feminino , Gota/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Ureia/sangueRESUMO
Genetic polymorphisms of very important pharmacogenomic (VIP) variants are important for personalized medicine. However, these have not been extensively studied in the Tibetan population. In this study, 82 VIP variants were detected in the Tibetan and Han (HAN) populations from northwestern China. Subsequently, we compared the differences between the Tibetan population and ten populations, including the HAN, Japanese in Tokyo (JPT), Mexican ancestry in Los Angeles (MEX), Toscans in Italy (TSI), African ancestry in Southwest USA (ASW), Luhya in California Webuye, Kenya (LWK), Gujarati Indians in Houston, Texas (GIH), Maasai in Kinyawa, Kenya (MKK), Yoruba in Ibadan, Nigeria (YRI), and Utah residents with Northern and Western European ancestry from the CEPH collection (CEU). Using the χ(2) test, we identified differences in the frequency distribution of 4, 4, 7, 10, 11, 11, 13, 15, 19, and 20 loci in the Tibetan population, compared to the HAN, JPT, MEX, TSI, ASW, LWK, GIH, MKK, YRI, and CEU populations, respectively [P < 0.05/(82*10)]. rs2115819, rs9934438, and rs689466, located in the ALOX5 (arachidonate 5-lipoxygenase), VKORC1 (vitamin K epoxide reductase complex, subunit 1) and PTGS2 (prostaglandin-endoperoxide synthase 2) genes, respectively, in the Tibetan population were different from those in most of the populations. Our results complement the information provided by the database of pharmacogenomics on Tibetan people, and provide an avenue for personalized treatment in the Tibetan population.
Assuntos
Araquidonato 5-Lipoxigenase/genética , Ciclo-Oxigenase 2/genética , Vitamina K Epóxido Redutases/genética , Adulto , Alelos , Povo Asiático , Feminino , Frequência do Gene , Genética Populacional , Genótipo , Haplótipos , Humanos , Masculino , Farmacogenética , Polimorfismo de Nucleotídeo Único , TibetRESUMO
This report describes a pediatric case of severe fever with thrombocytopenia syndrome (SFTS), which is an emerging disease that is caused by a novel bunyavirus. Interestingly, the previously reported SFTS cases typically involved elderly patients, while our case involved a 5-year-old child from Zhejiang Province, China. In this report, we describe our investigation of the clinical and epidemiological characteristics of this case, to improve our understanding of this emerging disease. Our principle finding was that the present case's clinical symptoms were milder than those that have been reported in adult cases of SFTS. Therefore, we recommend more careful screening of pediatric patients who present with mild symptoms that are consistent with SFTS.
Assuntos
Orthobunyavirus/isolamento & purificação , Febre por Flebótomos/diagnóstico , Febre por Flebótomos/patologia , Pré-Escolar , China , Feminino , HumanosRESUMO
Bitespiramycin is a macrolide antibiotic consisting of a mixture of some nine spiramycin ester derivatives. It has a similar spectrum of antibiotic activity to that of spiramycin but has superior pharmacokinetic properties. In this study, a rapid and facile LC/ESI-MSn method was applied to study the metabolism of bitespiramycin in rat following a single oral dose (80 mg kg-1). Concentrations of parent drug constituents and metabolites were determined in plasma, urine, feces and bile. Concentrations of parent drug constituents and metabolites in plasma were very low. In urine, feces and bile, parent drug constituents and 38 metabolites were identified on the basis of their chromatographic and mass spectrometric properties. The identity of 17 metabolites was confirmed by comparison with reference substances. The principal metabolites were the corresponding spiramycins formed by hydrolysis of the 4''-(3-methylbutanoate) groups. Other important metabolic pathways were: hydrolytic loss of the forosamine and mycarose sugars; aldehyde reduction; cysteine conjugation of the aldehyde group; and hydrolysis of the lactone ring. Products formed by lactone ring opening were found only in urine, and those formed by aldehyde reduction were found only in feces. Aldehyde reduction and hydrolytic loss of forosamine represent novel biotransformation pathways for spiramycin derivatives.
Assuntos
Antibacterianos/farmacocinética , Espiramicina/análogos & derivados , Espiramicina/farmacocinética , Administração Oral , Animais , Antibacterianos/administração & dosagem , Masculino , Ratos , Ratos Wistar , Espiramicina/administração & dosagemRESUMO
Recent clinical studies in China showed that As2O3 is an effective and relatively safe drug in the treatment of acute promyelocytic leukemia (APL). We found previously that As2O3 can trigger apoptosis of APL cell line NB4 cells, which is associated with downregulation of bcl-2 gene expression and modulation of PML-RAR alpha chimeric protein. To further understand the mechanisms of this alternative therapy for APL, we investigated in this report the effects of a wide range of concentrations of As2O2 on cultured primary APL cells, all-trans retinoic acid (ATRA)-susceptible (NB4 cells) and ATRA-resistant (MR2 subclone) APL cell lines. The results indicated that As2O3 had dose-dependent dual effects on APL cells: inducing preferentially apoptosis at relatively high concentrations (0.5 to 2 micromol/L) and inducing partial differentiation at low concentrations (0.1 to 0.5 micromol/L). The rapid modulation and degradation of PML-RAR alpha proteins, which was induced by As2O3 at 0.1 to 2 micromol/L, could contribute to these two effects. Bone marrow and peripheral blood examination showed that myelocyte-like cells, probably as a result of partial in vivo differentiation, and degenerative cells increased after 2 to 3 weeks of continuous in vivo As2O3 treatment when leukemic promyelocytes decreased. In conclusion, combination of induction of apoptosis and partial differention could be the main cellular mechanisms of As2O3 in the treatment of APL, and PML-RAR alpha could play an important role in determining the specific effects of As2O3 on APL cells.
Assuntos
Antineoplásicos/toxicidade , Intoxicação por Arsênico , Leucemia Promielocítica Aguda/tratamento farmacológico , Óxidos/toxicidade , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Trióxido de Arsênio , Arsenicais/uso terapêutico , Adesão Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , DNA de Neoplasias/análise , Resistencia a Medicamentos Antineoplásicos , Humanos , Imunofenotipagem , Cinética , Leucemia Promielocítica Aguda/patologia , Óxidos/uso terapêutico , Fagocitose/efeitos dos fármacos , Receptores do Ácido Retinoico/análise , Receptores do Ácido Retinoico/biossíntese , Receptor alfa de Ácido Retinoico , Frações Subcelulares/metabolismo , Fatores de Tempo , Tretinoína/toxicidade , Células Tumorais CultivadasRESUMO
It has been shown recently in China that arsenic trioxide (As2O3) is a very effective treatment for acute promyelocytic leukemia (APL). APL patients resistant to all-trans retinoic acid (ATRA) and conventional chemotherapy can still respond to AS2O3. In this study, we addressed the possible cellular and molecular mechanisms of this treatment by using NB4 cells as a model. The results show that: (1) As2O3 triggers relatively specific NB4 cell apoptosis at micromolar concentration, as proved by morphology, histogramic related nuclear DNA contents, and DNA gel eletrophoresis. (2) As2O3 does not influence bax, bcl-x, c-myc, and p53 gene expression, but downregulates bcl-2 gene expression at both mRNA and protein levels. (3) As2O3 induces a significant modulation of the PML staining pattern in NB4 cells and HL-60 cells. The micropunctates characteristic of PML-RAR alpha in NB4 cells dissappear after treatment with As2O3, whereas a diffuse PML staining occurs in the perinuclear cytoplasmic region. In addition, a low percentage of untreated NB4 cells exhibits an accumulation of PML positive particles in a compartment of cytoplasm. The percentage of these cells can be significantly increased after As2O3 treatment. A similar PML staining pattern is observed in apoptotic cells. (4) ATRA pretreatment does not influence As2O3-induced apoptosis. These results suggest that induction of cell apoptosis can be one of the mechanisms of the therapeutic effect of As2O3. Moreover, this apoptosis induction occurs independently of the retinoid pathway and may be mediated, at least partly, through the modulation of bcl-2, as well as PML-RAR alpha and/ or PML proteins.
Assuntos
Apoptose/efeitos dos fármacos , Arsenicais/farmacologia , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Leucemia Promielocítica Aguda/patologia , Proteínas de Neoplasias/biossíntese , Proteínas de Fusão Oncogênica/biossíntese , Óxidos/farmacologia , Proteínas Proto-Oncogênicas/biossíntese , Trióxido de Arsênio , Arsenicais/uso terapêutico , Células HL-60/efeitos dos fármacos , Humanos , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/genética , Linfoma Difuso de Grandes Células B/patologia , Medicina Tradicional Chinesa , Monócitos/efeitos dos fármacos , Proteínas de Neoplasias/genética , Proteínas de Fusão Oncogênica/genética , Óxidos/uso terapêutico , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-bcl-2 , RNA Mensageiro/biossíntese , RNA Neoplásico/biossíntese , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
Retinoic acids exert a wide physiological role in development and differentiation. Retinoic acids have also been used in the treatment of human cancers, particularly in acute promyelocytic leukemia (APL). A structure-function relationship of the RA isomers in terms of clinical effect has been observed since all-trans retinoic acid (ATRA) induces a high complete remission rate while 13-cis retinoic acid (13-cis RA) shows much poorer effect. In this study, we examined the effect of RA isomers, including ATRA, 13-cis RA and 9-cis RA, on the proliferation and differentiation of NB4 cells. A number of parameters such as cell growth curve, dynamics of cell cycle, expression of clusters of differentiation and reduction of nitro blue tetrazolium (NBT) as well as immunofluorescence staining of PML were used to evaluate the effects of three isomers at two concentrations (10(-8) M and 10(-7) M). It has been shown that during the first 48 h of RA treatment, the APL cell differentiation was coupled with the cell proliferation. Although similar effects of proliferation inhibition and differentiation induction were observed among the three isomers at 10(-7) M, significant differences appeared at a concentration of 10(-8) M, 9-cis RA showed a higher activity than that of ATRA, while ATRA showed better results than 13-cis RA. Our results provide further evidence that 9-cis RA could be a promising molecule in differentiation induction of malignant cells.
Assuntos
Leucemia Promielocítica Aguda/patologia , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares , Fatores de Transcrição/metabolismo , Tretinoína/farmacologia , Antígenos CD/metabolismo , Ciclo Celular , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Humanos , Isomerismo , Isotretinoína/farmacologia , Proteína da Leucemia Promielocítica , Receptores do Ácido Retinoico/efeitos dos fármacos , Receptores do Ácido Retinoico/metabolismo , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Proteínas Supressoras de TumorRESUMO
Electron spin resonance (ESR) and high-performance liquid chromatography (HPLC) techniques were utilized to investigate the effect of deferoxamine on free radical generation in the reaction of Cr(V) with H2O2 and organic hydroperoxides. ESR measurements demonstrated that deferoxamine can efficiently reduce the concentration of the Cr(V) intermediate as formed in the reduction of Cr(VI) by NAD(P)H or a flavoenzyme glutathione reductase/NADH. ESR spin trapping studies showed that deferoxamine also inhibits Cr(V)-mediated .OH radical generation from H2O2, as well as Cr(V)-mediated alkyl and alkoxy radical formation from t-butyl hydroperoxide and cumene hydroperoxide. HPLC measurements showed that .OH radicals generated by the Cr(VI)/flavoenzyme/NAD(P)H enzymatic system react with 2'-deoxyguanine to form 8-hydroxy-2'-deoxyguanine (8-OHdG), a DNA damage marker. Deferoxamine effectly inhibited the formation of 8-OHdG also.
Assuntos
Cromatos/farmacologia , Desferroxamina/farmacologia , Desoxiguanosina/antagonistas & inibidores , Hidróxidos/química , Animais , Bovinos , Cromatos/química , Cromatografia Líquida de Alta Pressão , Desoxiguanosina/análogos & derivados , Desoxiguanosina/química , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres , Peróxido de Hidrogênio/química , Radical Hidroxila , Hidroxilação/efeitos dos fármacos , OxirreduçãoRESUMO
To determine the influence of hypovolemia on the control of forearm vascular resistance (FVR) during dynamic exercise, we studied five physically active men during 60 min of supine cycle ergometer exercise bouts at 35 degrees C in control (normovolemic) and hypovolemic conditions. Hypovolemia was achieved by 3 days of diuretic administration and resulted in an average decrease in plasma volume of 15.9%. Relative to normovolemia, hypovolemia caused an attenuation of the progressive rise in forearm blood flow (P less than 0.05) and an increase in heart rate (P less than 0.05) during exercise. Because mean arterial blood pressure during hypovolemic exercise was well maintained, the attenuation of forearm blood flow was due entirely to a relative increase in FVR. At the onset of dynamic exercise, FVR was increased significantly in control and hypovolemic conditions by 13.2 and 27.1 units, respectively. The increase in FVR was significantly different between control and hypovolemic conditions as well. We attributed the increased vasoconstrictor bias during hypovolemia to cardiopulmonary baroreceptor unloading and/or an increased sensitivity to cardiopulmonary baroreceptor unloading. We concluded that reduced blood flow to the periphery during exercise in the hypovolemic condition was caused entirely by an increase in vascular resistance, thereby preserving arterial blood pressure and adequate perfusion to the organs requiring increased flow.
Assuntos
Exercício Físico/fisiologia , Antebraço/irrigação sanguínea , Temperatura Alta , Choque/fisiopatologia , Resistência Vascular/fisiologia , Adulto , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pletismografia , Pressorreceptores/fisiologia , Reflexo/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Pele/irrigação sanguínea , Volume Sistólico/fisiologiaRESUMO
Electron spin resonance (ESR) measurements on solutions and isolated powders provide direct evidence for the involvement of Cr(V) species in the reduction of Cr(VI) by NAD(P)H. ESR analysis of an isolated Cr(V)-NAD(P)H solid yields g parallel = 1.9831 and g perpendicular = 1.9772, indicating that the unpaired electron occupies the dz2 orbital of the Cr(V) ion, with square-pyramidal geometry. Addition of hydrogen peroxide (H2O2) to the NAD(P)H-Cr(VI) reaction mixtures suppresses the Cr(V) species and generates hydroxyl (.OH) radicals. The .OH radicals were detected via ESR spin trapping, employing 5,5-dimethyl-1-pyrroline-N-oxide and alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone as spin traps. The dependence of Cr(V) and .OH radical formation on the H2O2 and Cr(VI) concentrations indicates that the Cr(V) species react with H2O2 to generate the .OH radicals. Similar results were obtained by using various diols (arabinose, cellobiose, FAD, fructose, glyceraldehyde, ribose, and tartaric acid), alpha-hydroxycarboxylic acids, and glutathione. Investigations with superoxide dismutase showed no significant participation of O2- in the generation of .OH radicals. These results thus indicate that the Cr(V) complexes, produced in the reduction of Cr(VI) by cellular reductants, react with H2O2 to generate .OH radicals, which might be initiators of the primary events in the Cr(VI) cytotoxicity.
Assuntos
Cromo , Peróxido de Hidrogênio , Hidróxidos , Cromo/farmacologia , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres , Glutationa , Radical Hidroxila , Cinética , Marcadores de SpinRESUMO
The stimulus-response characteristics of cardiopulmonary baroreflex control of forearm vascular resistance (FVR) were studied in five unfit [UF, maximal O2 consumption (VO2 max) = 38.5 ml X min-1 X kg-1] and six fit (F, VO2 max = 57.0 ml X min-1 X kg-1) subjects. We assessed the relationship between reflex stimulus, i.e., changes in central venous pressure (CVP) and response, i.e., FVR, during selective unloading of the cardiopulmonary mechanoreceptors with lower body negative pressure (0 to -20 mmHg). The linear relationship between FVR and CVP, the gain of this baroreflex, was significantly diminished in the F subjects, -2.42 +/- 0.57 U/mmHg, compared with the UF, -5.15 +/- 0.58 U/mmHg. Both groups, F and UF, had similar resting values for CVP and FVR; thus the diminished gain in F subjects was not simply an artifact resulting from a shift of the set point along the baroreflex stimulus-response curve. We also found a linear relationship between baroreflex gain and total blood volume (r = 0.59, P less than 0.05). We conclude that the gain of this vascular reflex is attenuated in trained individuals and is related to cardiovascular adaptations, such as an increased blood volume, associated with exercise training.