This research was conducted to investigate the connective tissue contribution to toughness of cow beef and to find means to decrease it. Intra muscular connective tissue (IMCT) content of meat from cows (~6 years) and heifers (~16 months) varied significantly among muscles (P<0.0001) and maturity groups (P<0.05). Amount of total collagen in IMCT was a constant (37.3-46.3 %) among muscles and between maturity groups. Shear force of <i>biceps femoris</i>, <i>semimembranosus</i> and <i>longissimus</i> muscles had increased significantly with animal maturity (P<0.0001). Shear stress of <i>gluteus medius</i> was similar between maturity groups. Collagen solubility decreased with animal maturity, except for <i>biceps femoris</i>. <p> The impact of the temperature of aqueous heating (55 to 95 ºC) and time on thermolabile proteins, amorphous proteins, Ehrlich chromogen, pyridinoline, thickness change, shrinkage, weight gain, shear force, amide bands and morphology of epimysium was studied. Collagen contributed to 90% (w/w) of epimysial proteins. At 55 ºC, epimysial properties were changed only after exposure to long heating times. Shear stress values of raw cow (39.6 N/mm2) and heifer (30.8 N/mm2) epimysium decreased significantly to 11.6 and 2.1 N/mm2, respectively, at 70 ºC. Amount of epimysial amorphous collagen (14-16% w/w) detected after heating at 70 ºC and above was not related to shear stress decrease. Before and after heating, cow epimysium contained more pyridinoline cross-links than heifer epimysium.<p> The effects of strong and weak acids and alkalis on epimysial properties were studied following heating at 55 and 70 ºC for 15 min. As the concentration of HCl (0.1-0.5 M) and pre-equilibration time were increased at 70 ºC, shear stress decreased to <2 N/mm2. Increasing concentration of CH3COOH (0.1-0.5 M) and pre-equilibration times had decreased shear stress to ~5 N/mm2. At 55 ºC, HCl was not superior to CH3COOH in its ability to decrease epimysial shear stress. Increasing concentration of NaOH (0.01-0.05 M) and high temperature decreased shear stress to ~3 N/mm2. Lack of a shear stress decrease at 55 ºC and increased thermal denaturation temperature (66 ºC compared to 63 ºC in water), indicated that NH4OH had an epimysial stabilization effect, which was not eliminated at 55 ºC.

Activity of skeletal muscles produce electrical signals that can be measured using electrodes placed on the skin surface over a target muscle or with electrodes inserted into the muscle. Such electromyographic (EMG) signals provide fundamental information about the intensity of the neural drive acting upon muscle. In addition, EMG signals are widely deployed as control sources for powered prosthetic limbs. One limitation related to recording EMG signals, however, is that signals arising from neighboring muscles may contribute significantly to the activity detected with electrodes placed over or within a given target muscle. Such unwanted contribution of signal from muscles other than the targeted muscle is referred to as cross-talk. Cross-talk was investigated in four neighboring muscles in the forearm with different electrode types and configurations: bipolar intramuscular, monopolar intramuscular, and bipolar surface EMG. Cross-correlation analysis was performed for every pairwise combination of EMG signal recorded. The peak correlation coefficient at near-zero time delay provided an index of the degree of cross-talk. Correlation coefficients dropped off exponentially with distance between recording electrodes. Bipolar intramuscular EMG had the narrowest pick-up range, with a length constant of 14.5 mm. Bipolar surface EMG had a longer length constant of 37.0 mm, whereas monopolar intramuscular EMG had the longest length constant of 64.5 mm. A second set of experiments indicated that correlation in EMG signals detected in different muscles was unlikely to have a neural basis. Therefore, because of their wide detection range, monopolar configurations including those involving intramuscular electrodes, should be avoided.

Supraspinatus (SSP) tendon tear leads to intramuscular fat accumulation in the SSP muscle and the mechanisms are currently unknown. The purpose of this study was to investigate changes in vascularization of the SSP muscle and the relationship to intramuscular fat accumulation following SSP tendon detachment with or without reattachment. One hundred and six rabbits underwent SSP tendon detachment. In groups of ten, thirty rabbits were sacrificed 4, 8, and 12 weeks following detachment. Forty rabbits underwent detachment and immediate reattachment and were sacrificed in groups of ten following 0, 1, 2, and 6 weeks of healing. In groups of twelve, the remaining thirty-six rabbits underwent SSP tendon reattachment 4, 8, and 12 weeks after detachment and were sacrificed 12 weeks later. Vascularization was quantified in each specimen using CD31 immunohistochemistry. Four weeks after SSP tendon detachment, there was an increase in vascularization of the distal SSP muscle that reached significance after 12 weeks of detachment (p=0.024). We found that vascularization was positively correlated with intramuscular fat accumulation after detachment only (r=0.29; p=0.008). After SSP tendon reattachment, immediate or delayed, the correlation between vascularization and intramuscular fat accumulation was not observed. Microscopically, some SSP muscle vascular structures in the reattachment group had thicker vascular walls which were further quantified using αSMA immunohistochemistry. The delayed reattachment group showed an increase in vascular wall thickness in the distal portion of the SSP muscle at 4+12 (p=0.012) and 12+12 (p=0.012) weeks and in the proximal portion at 4+12 (p=0.024) weeks. Further investigation is required to demonstrate a cause/effect relationship between increased vascularization and intramuscular fat accumulation in the context of rotator cuff tear and success of surgical repair.

Made available in DSpace on 2014-10-09T12:35:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:56Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:35:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:56Z (GMT). No. of bitstreams: 0 / Níveis sustentáveis de hormônio de crescimento humano (hGH) circulante e aumento de peso altamente significativo, avaliados também em comparação a repetidas injeções de hormônio, foram observados em trabalhos anteriores, baseados na eletrotransferência de DNA plasmidial no músculo de camundongos anões imunodeficientes (lit/scid). No presente trabalho, um modelo animal homólogo de terapia gênica para GH foi estudado mediante clonagem da sequência genômica do DNA de GH de camundongo (mGH-gDNA), a qual substituiu o hGH-gDNA no vetor que havia sido utilizado em camundongos anões imunodeficientes. O novo vetor, agora nomeado UBI-mGH-gDNA, foi utilizado em camundongos anões imunocompetentes (lit/lit). Foi primeiramente realizado um teste in vitro, transfectando-se células humanas HEK 293 com este plasmídeo e obtendo-se uma expressão de 3,0 &mu;g mGH/106 células/dia, contra 3,7 &mu;g mGH/106 células/dia, para o UBI-hGH-gDNA. Estes dois plasmídeos foram então injetados (50 &mu;g/animal) no músculo quadríceps de camundongos, seguido de eletroporação, realizando um ensaio de 94 dias. Enquanto após 15 dias, as inclinações das curvas de variação de peso relacionadas ao mGH, hGH e salina foram 0,130, 0,112 e 0,027 g/camundongo/dia, respectivamente, após 94 dias, as inclinações correspondentes foram 0,041, 0,028 e 0,033 g/camundongo/dia. As análises estatísticas mostraram que após 15 dias, as inclinações das duas curvas com o GH foram significativamente maiores que a inclinação do controle (P<0,001), enquanto que após 94 dias, somente a inclinação da curva do mGH foi maior que a do controle (P<0,005). A porcentagem de aumento de peso nos animais tratados com o gene do mGH, após 94 dias, foi de 34,3%, enquanto que o comprimento nariz-cauda e o comprimento do fêmur, dois parâmetros que medem diretamente o crescimento longitudinal, foram de 9,5% e 26%, respectivamente, quando comparados aos valores iniciais. A interrupção do crescimento progressivo do grupo tratado com hGH não foi inesperada, considerando a óbvia reação imunogênica dos animais imunocompetentes contra o GH humano e não contra o de camundongo (título do anticorpo anti-hGH 1:100 a 1:3200). A inclinação altamente positiva do grupo controle, já observada em camundongos lit/lit mas não em lit/scid, é provavelmente devida ao ganho de peso natural desta linhagem, não suportada, contudo, por um proporcional crescimento longitudinal. Níveis circulatórios de mGH da ordem de 4 ng/mL foram detectados após 15 dias para o grupo tratado com o mGH, enquanto o grupo controle apresentou níveis em torno de 0,7 ng mGH/mL (P<0,001). Níveis circulatórios de mIGF-I foram também determinados nos dias 15, 45 e 94 nos animais tratados com mGH, sempre mostrando valores 1,5 - 3,0 vezes maiores que o grupo controle, e valores 1,2-1,6 vezes maiores que o grupo tratado com hGH. Este modelo de tratamento homólogo pode ser considerado uma primeira abordagem e um importante suporte para futuros ensaios pré-clínicos baseados na administração de DNA plasmidial para o tratamento da deficiência de GH humano. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Women are four to eight times more likely to injure their anterior cruciate ligament (ACL) compared to men. It is most commonly injured through a non-contact mechanism during game time situations. During landings, women display valgus collapse, where a less active gluteus medius muscle (GMed) may be unable to control the internal rotation of the thigh, causing an increase in knee joint abduction angle, augmenting the risk of ACL injury. This study’s purpose was to determine the difference between 12 male and 12 female athletes in muscle activity, specifically the GMed, and the 3D kinematics and kinetics of the lower-limb during drop jump landings from three heights; maximum vertical jump height, tibial length, and a commonly used height of 40cm. Results showed that females had greater hip adduction and knee abduction angles compared to men. The GMed activity showed no significant differences between sexes at each drop jump height.

Context: Clinicians use a number of superficial and deep heating modalities, including pulsed shortwave diathermy (PSWD) and moist hot packs, in the clinical setting. Recently, a continuous diathermy unit called ReBound was introduced into the clinical setting. Its effectiveness as a heating modality is unknown. Objective: To compare the effects of PSWD, moist hot packs and the ReBound unit on tissue temperature in the triceps surae muscle. Design: A 3 x 27 factorial cross-over design with repeated measures. Setting: University research laboratory. Subjects: Twelve healthy college-aged volunteers (4 men, 8 women; age = 22.2 ± 2.25; calf subcutaneous fat thickness = .72 cm ± .19 cm). Interventions: On three different days separated by at least 48 hours, one of three modality treatments (PSWD, moist hot packs or ReBound unit) selected using a Latin-square was applied to the triceps surae muscle of each participant for 30 minutes. After the 30 minute treatment, the modality was removed and temperature decay was recorded for 20 minutes. Main Outcome Measures: Medial triceps surae intramuscular tissue temperature at 1 cm and 3 cm deep was measured using implantable thermocouples inserted horizontally into the muscle. Measurements were taken every 5 minutes during the 30 minute treatment and every minute during the 20 minute temperature decay for a total of 50 minutes. A 3 x 27 mixed model analysis of variance blocking by subject was used to assess the effects of treatments and time, and their interaction on the tissue temperature at 1 cm and 3 cm depths. Results: A significant treatment by time interaction main effect was found for tissue temperature increase at each depth, 1 cm (F52, 572 =14.66, p < .0001) and 3 cm (F52, 572 = 17.86, p < .0001). Post-hoc measures revealed that tissue temperature significantly increased with the PSWD over the ReBound unit and moist hot packs at 1 cm and 3 cm depths. There was no significant difference between the ReBound unit and moist hot packs throughout the treatment and temperature decay. The greatest mean tissue temperature increase from baseline was observed with the PSWD unit at 1 cm (5.96°C ± 2.04°C) and at 3 cm (4.32°C ± 1.79°C). There was no statistical difference between the increases observed with the ReBound (1 cm: 3.69°C ± 1.50; 3 cm: 2.31°C ± .87) and moist hot packs (1 cm: 2.82°C ± .90; 3 cm: 1.56°C ± 1.00). Conclusions: During a 30 minute treatment, PSWD was the most effective at increasing intramuscular tissue temperature of the triceps surae muscle group. There was no significant difference between the effectiveness of moist hot packs and the ReBound continuous diathermy unit in increasing intramuscular tissue temperature.

Therapeutic ultrasound is a deep heating modality often used to produce vigorous heating (≥4°C Δ) in tissues. The vigorous heating effects of 3 MHz therapeutic ultrasound have only been tested to a 2.5 cm depth, but its maximal depth of producing vigorous heating has yet to be established. Objective: To investigate the tissue temperature change produced by a 3 MHz ultrasound treatment at depths of 3 and 3.5 cm in the human triceps surae muscle group. Design: Randomized control design. Setting: Therapeutic modalities research laboratory. Patients or Other Participants: Twenty healthy college-aged participants (male = 13, female = 7; age = 23.4 ± 1.31; calf subcutaneous fat thickness= 0.6 cm ± 0.2 cm). Participants were randomized into treatment (n = 15) and sham (n = 5) groups. Participants were blinded to their group assignment. Interventions: Two MT-26/6 needle thermocouples were inserted into the left posterior triceps surae at depths of 3.0 ± 0.1cm and 3.5 ± 0.1cm from the skin's surface. Participants in the treatment group received a continuous 3 MHz ultrasound treatment at 1.4 W/cm2 for 8 minutes with 10mL of 100% ultrasound gel as a coupling medium. Participants in the sham group received the same treatment parameters, but the ultrasound device was not turned on. The Omnisound 3000 ultrasound device (ERA = 4.2cm2, BNR = 3.0:1) was used for all treatments. A 15 cm2 template was used to ensure a constant and proper treatment size. Baseline temperature (TB) was established by taking a mean of intramuscular tissue temperature (TIM)for five minutes before the treatment and TIM were recorded every 10 seconds throughout the experiment session. Participants marked a visual analog scale (VAS) indicating heat sensation at pre-treatment and post-treatment. Main Outcome Measures: A 2 x 2 x 2 (probe depth x condition x time) ANCOVA with TB used as a covariate analyzed the difference in TIM. We only used the time points of baseline and final TIM for our analysis as we are only interested in the change in TIM from beginning to end of the ultrasound treatment. Descriptive statistics for TIM and VAS for heat sensation were computed as post-treatment minus pre-treatment for each condition and probe depth. Results: There was a significant difference in TIM between the conditions at the different probe depths from the beginning and end of the ultrasound treatment (F1,15 = 7.35, p = 0.016). The mean changes in TIM for each condition at each probe depth were: sham 3cm = -0.4 ± 0.3°C, sham, 3.5cm = -0.2 ± 0.3°C, treatment, 3cm = 4.4 ± 0.2°C, treatment, 3.5cm = 3.5 ± 0.2°C. Mean VAS scores for each group were: sham = 0 ± 0mm and treatment = 71.8 ± 11.8mm. Conclusions: At 3cm deep into the posterior calf, the Omnisound 3000 using a 3 MHz treatment produced vigorous heating (≥4°C Δ). Moderate heating (2-3°C Δ) occurred at 3.5cm deep into the calf. Three MHz ultrasound may be used to heat tissues deeper than previously theorized, but it does, however, create a moderately high level of heat sensation for the patient.

Orientador: Fernando Sebastián Baldi Rey / Resumo: A compreensão de processos regulatórios e organização molecular dos organismos vivos progrediram consideravelmente na última década. As metodologias também evoluíram com o sequenciamento de DNA e RNA e de ferramentas genômicas permitindo a análise de centenas ou milhares de genes, proteínas ou metabólitos. O uso simultâneo dessas informações auxilia na obteção de informações relevantes sobre as variáveis que envolvem as variações fenotípicas de características de interesse. O objetivo do presente estudo foi integrar dados fenotípicos, genotípicos e transcriptômicos em busca de aprimoramento sobre os mecanismos genéticos e metabólicos que determinam o perfil de ácidos graxos na carne de bovinos Nelore, a fim de contribuir para o melhoramento da composição de ácidos graxos da carne. Foram utilizados machos da raça Nelore terminados em confinamento, abatidos com média de idade 24 meses. Amostras do músculo L. thoracis, entre a 12ª a 13ª costela foram coletadas para as análises de perfil de ácidos graxos, extração de RNA e de DNA. Os resultados foram apresentados nos capítulos 2 e 3. No capítulo 2, o objetivo foi identificar genes diferencialmente expressos pelo método RNA-seq e perfil de ácidos graxos no músculo L. thoracis com uso de componentes principais (principal components: PC). Foram selecionados dois grupos de 10 animais, os quais possuíam valores de PC1 e PC2 extremos (Alto x Baixo) para os grupos somatórios de ácidos graxos (AG): ácidos graxos saturados (AGS), ácidos g... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The understanding of regulatory processes and molecular organization of organisms has progressed considerably in the last 10 years.The methodologies also evolved with the sequencing of DNA, RNA and genomic tools allowing the analysis a lot of genes, proteins or metabolites. The simultaneous use of this information should help to obtain relevant information about the variables that result the phenotypic variations of traits of interest. The objective of the present study was to integrate phenotypic, genotypic and transcriptomic studies in order to clarify the genetic and metabolic mechanisms that determine the fatty acid profile in Nelore beef, in order to contribute to the improvement of the fatty acid composition of the meat. Nelore males were used in feedlot, coming from farms that integrate three breeding programs and slaughtered with an average of 24 months. Samples of the L. thoracis muscle between the 12th to 13th rib were collected for analysis of fatty acid profile, RNA and DNA extraction. The results were presented in chapters 2 and 3. In chapter 2, the objective was to identify genes differentially expressed by RNA-seq method and fatty acid profile in the L. thoracis muscle with the use of Principal Components (PC). Two groups of 10 animals were selected, which had PC1 and PC2 extreme values (High x Low) for the fatty acids (FA) groups: saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), omega 3 (n-3) and omega 6 (n-6... (Complete abstract click electronic access below) / Doutor

Estudos atuais mencionam os efeitos benéficos proporcionados pelo aleitamento materno e contato pele-a-pele no alívio da dor aguda em RN. A maioria dos estudos que trazem a amamentação como medida de alívio da dor aguda durante a administração da vacina intramuscular são feitos com bebês com mais de dois meses de idade. O objetivo deste estudo foi avaliar o efeito da amamentação materna na resposta à dor e ao estresse do RN submetido à vacina intramuscular contra Hepatite B, em comparação ao contato pele-a-pele. Trata-se de um estudo analítico de caráter experimental, do tipo ensaio clínico randomizado, realizado no Centro de Referência da Saúde da Mulher de Ribeirão Preto - MATER, no período de janeiro de 2009 a maio de 2010. A amostra constituiu-se de 55 bebês a termo que foram divididos aleatoriamente em dois grupos: grupo A (contato pele-a-pele), composto por 28 RN, que foram mantidos por 5 minutos em berço comum (período basal), 15 minutos em contato pele-a-pele antes da administração da vacina, (período de tratamento), durante todo o período de antissepsia/ injeção, durante a compressão e até 5 minutos após o término do procedimento (período de recuperação); e grupo B (aleitamento materno), composto por 27 RN, que foram mantidos em berço comum por 5 minutos (período basal), 5 minutos em contato pele-a-pele iniciando no 5° minuto o aleitamento materno (10 minutos no período de tratamento) e sendo mantidos nesta condição durante a antissepsia/ injeção, o período de compressão, e a recuperação (5 minutos após o término da compressão). O projeto foi aprovado pelo Comitê de Ética em Pesquisa da Instituição e pelo Comitê de Ética em Pesquisa da EERP - USP, e o Termo de Consentimento Livre e Esclarecido foi firmado com as mães dos RN antes da coleta dos dados. O procedimento de coleta constituiu-se da monitorização da frequência cardíaca e filmagem para posterior análise das manifestações comportamentais (mímica facial por meio da escala NFCS adaptada) e fisiológicas dos RN. Os resultados dos grupos A e B foram comparados em todos os períodos. A normalidade das distribuições das variáveis quantitativas foi testada por meio do teste de Kolmorogov-Smirnov. Se normalmente distribuídos, foi utilizada a ANOVA. O teste de Mann-Whitney foi utilizado quando a normalidade não foi satisfeita. Para variáveis categóricas utilizamos o teste Qui-quadrado ou teste exato de Fisher. O nível de significância utilizado foi de &#945; &#8805; 0,05. Para verificação de diferenças entre os escores de NFCS entre os grupos e períodos (intra grupos) foram utilizados o teste não paramétrico Mann-Whitney para duas amostras independentes e o teste não paramétrico Friedman para mais do que duas amostras dependentes, seguido de comparações múltiplas, respectivamente. Para o resultado do teste Mann Whitney e para as comparações múltiplas, o teste de Wilcoxon foi utilizado, considerando-se o ajuste do valor do nível de significância &#945;= 0,05 pelo número de comparações. O teste Mann Whitney mostrou diferenças entre os grupos e o percentual de manifestações de mímica facial, ocorrendo em proporção significativamente maior no grupo A quando comparado ao grupo B, no período basal (p=0,003), de compressão (p=0) e recuperação (p=0), ou seja, os bebês do grupo B se recuperaram melhor e mais rápido quando comparados aos bebês do grupo A. Na análise intra grupos, o teste de Friedman com &#945; = 0,005 ajustado, mostrou que para o grupo A houve diferença estatisticamente significativa em quase todos os períodos com exceção do período basal para o tratamento (p=0,010) e para o grupo B tivemos diferenças estatisticamente significativa para quase todos os períodos com exceção dos períodos basal para o tratamento (p=0,808), e da compressão para a recuperação (p=0,064). Para verificação de diferenças entre os escores de FC entre os grupos e intra grupos foi utilizada a Análise Variância com Medidas Repetidas. Como a interação foi significativa (p=0,05) testes de comparações múltiplas foram aplicados. Para comparações múltiplas entre grupos utilizou-se o teste t de "Student" para duas amostras independentes e intra grupos, o teste t de "Student" pareado para duas amostras dependentes. Em ambas as análises, o valor de &#945; foi ajustado segundo o número de comparações realizadas. Considerando os valores médios da FC, tivemos diferença estatisticamente significativa entre os grupos A e B no período da antissepsia/ injeção (p=0,004), ou seja, os bebês do grupo A apresentaram valores maiores de FC quando comparados aos do grupo B, durante este período. Na análise intra grupos o teste t de "Student" pareado com &#945; = 0,005 ajustado mostrou diferença estatísticamente significativa em quase todos os períodos com exceção do período basal para o período de tratamento, e para o grupo B estatísticamente significativa em quase todos os períodos com exceção do período basal para o tratamento (p=0,617) e da antissepsia/ injeção para a compressão (p=0,425) . Conclui-se que a amamentação materna foi eficaz na redução das respostas relacionadas à dor decorrente da administração intramuscular da vacina contra hepatite B, pois os resultados mostraram redução da mímica facial no grupo B nos períodos de compressão e recuperação e redução nos valores da FC durante a antissepsia/ injeção, mostrando que estes bebês recuperaram-se mais rápido quando comparados aos do grupo A. / Current studies address the benefits provided by breast feeding and skin to skin contact in the relief of acute pain in new born infants (NB). Most studies that approach breast feeding as a measure of pain relief during the administration of intramuscular vaccine are carried out with babies older than 2 months of age. This study aimed to evaluate the effect of breast feeding in response to pain and stress of NB undergoing intramuscular vaccine against Hepatitis B, compared to skin-to-skin contact. This analytical experimental study is a randomized clinical trial, carried out at the Reference Center for Women Health in Ribeirão Preto - MATER, from January 2009 to May 2010. The sample consisted of 55 term NB who were randomly divided into two groups: group A (skin-to-skin contact), composed of 28 NB, who were kept for 5 minutes in an ordinary crib (baseline period), 15 minutes in skin-to-skin contact prior to the administration of the vaccine (treatment period), during the entire period of antisepsis/injection, during the compression and up to 5 minutes after the end of the procedure (recovery period); and group B (breast feeding) composed of 27 NB who were kept in an ordinary crib for 5 minutes (baseline period), 5 minutes on skinto- skin contact beginning breast feeding at the 5th minute (10 minutes in the treatment period) and being kept in this condition during antisepsis/ injection, the compression period, and recovery (5 minutes after the end of compression). The project was approved by the Ethics Research Committee of the Institution and by the Ethics Research Committee of the EERP-USP, and the Free and Informed Consent Form was signed by the mothers of the infants prior to data collection. The collection procedure consisted of monitoring the heart rate (HR) and recording images for later analysis of behavioral manifestations (facial expressions through the adapted NFCS scale) and physiological parameters of the NB. Results of groups A and B were compared in all periods. The normal distribution of quantitative variables was tested by the Kolmorogov-Smirnov test. If normally distributed, ANOVA was used. The Mann-Whitney test was used when normality was not met. For categorical variables the Chi-square test or Fisher's exact test were used. The level of significance used was &#945; &#8805; 0.05. In order to check for differences between NFCS scores between groups and periods (intra groups) nonparametric Mann-Whitney test was used for two independent samples and the Friedman nonparametric test for more than two dependent samples, followed by multiple comparisons, respectively. For the result of the Mann-Whitney test and for multiple comparisons, the Wilcoxon test was used, considering the value adjustment of the level of significance &#945; = 0.05 by the number of comparisons. Regarding checking the differences between the scores of HR between groups and intra groups, Variance Analysis with Repeated Measures was used. As the interaction was significant (p = 0.05), multiple comparison tests were applied. For multiple comparisons between groups, Student's t test was used for two independent samples and intra groups, and paired Student's t test for two dependent samples. In both analysis, the alpha value was adjusted according to the number of comparisons carried out. The significance level used was 0.05 (&#945; = 0.05). Mann- Whitney test showed differences between groups and the percentage of facial expressions, with a significantly higher occurrence in group A compared to group B, at baseline period (p = 0.003), compression (p=0) and recovery (p=0), that is, infants in group B recovered better and faster when compared to babies in group A. In the intra groups, the Friedman test with adjusted &#945; = 0.005 showed that for group A there was statistically significant difference for all periods except for baseline period for baseline treatment (p=0.010) and for group B there was statistically significant differences for all periods except baseline period for treatment (p=0.808), and compression for recovery (p=0.064). Considering the average values of HR, there was statistically significant difference between groups A and B during the antisepsis/ injection (p=0.004), that is, infants in group A had higher values of HR when compared to Group B during this period. In the intra group analysis, the paired Student's t test with adjusted &#945; = 0.005 showed statistically significant difference in all periods except the baseline period for the treatment period, and group B showed statistically significant difference in all periods except for baseline period for treatment (p=0.617) and antisepsis/injection for the compression (p=0.425). It was concluded that breast feeding was effective in reducing responses related to pain caused by intramuscular administration of hepatitis B vaccine, since the results showed reduction of facial expressions, in group B during periods of compression and recovery, and reduction in the values of HR during antisepsis/injection, showing that these babies have recovered faster when compared to Group A.