Sleep deprivation increases pain sensitivity following acute muscle soreness.

OBJECTIVE: The aim of this cross-sectional group comparison study was to investigate whether sleep disturbance facilitates pain sensitivity caused by an acute muscle injury. METHODS: Thirty-six healthy individuals were included and randomly assigned to one of three groups in a non-balanced manner: a control group (n = 11) and two groups who performed eccentric exercise for quadriceps to cause delayed onset of muscle soreness (DOMS). The difference between the DOMS groups was that one followed their habitual sleep pattern (Sleep group, n = 12) and the other had their sleep withdrawn for one night (No-Sleep group, n = 13). The level of DOMS was indicated using a 6-point Likert Scale and pain sensitivity was assessed using Pressure Pain Thresholds (PPT) at the lower legs and shoulder at baseline (Day-1) and after 48 h (Day-3). Additionally, pain distribution following suprathreshold pressure stimulation (STPS) on the quadriceps muscle was assessed on the same days. RESULTS: PPTs were significantly reduced at Day-3 compared with Day-1 in both DOMS groups. The relative change between days was larger in the No-Sleep group compared with controls (P<0.05) whilst no significant change was seen in the Sleep group compared with controls. Furthermore, no significant differences were found between groups nor days for the subjective perception of DOMS (Likert Scale) and the size of the area of STPS. CONCLUSIONS: The loss of sleep further increases pain sensitivity following an acute soft tissue injury, demonstrating a potential causative role of the lack of sleep on complex pain states following musculoskeletal injuries.

Human Bifidobacterium strains as adjunct cultures in Spanish sheep milk cheese.

Three bifidobacteria strains of human origin (Bifidobacterium pseudolongum INIA P2, Bifidobacterium breve INIA P734, and Bifidobacterium longum INIA P678) were used as potential probiotic adjunct cultures for the manufacture of pasteurized sheep milk cheese. Bifidobacteria were inoculated at 5 to 6 log cfu/mL in milk vats. Microbiological, physicochemical, rheological, color, and sensory characteristics were determined at 7, 28, and 60 d of ripening. Counts of B. pseudolongum INIA P2 remained above 6 log cfu/g during 60 d of ripening as well as after further simulated gastrointestinal digestion of cheeses. Bifidobacterium breve INIA P734 counts remained stable during 28 d and decreased by less than 1 log unit after simulated digestion. Bifidobacterium longum INIA P678 counts dropped sharply during cheese manufacture and ripening and were below detection level after simulated digestion. Addition of bifidobacteria strains did not affect starter viability, cheese pH, dry matter, water activity, or salt content but significantly increased overall proteolysis and the concentration of some free amino acids. Cheeses with bifidobacteria exhibited no significant differences in most sensory characteristics with respect to control cheese. According to our results, B. breve INIA P734 and B. pseudolongum INIA P2 are promising candidates as probiotic adjunct cultures in fresh and semi-hard sheep milk cheese.

Bifidobacterial strains shared by mother and child as source of probiotics.

Importance of bifidobacteria as part of the infant intestinal microbiota has been highlighted. Their acquisition is influenced by the mode of birth and the feed regime afterwards, with a special role of the maternal microbiota. The presence of the same shared bifidobacterial strains between breast milk and infant faeces in 14 mother-infant pairs was assessed by means of pulsed-field gel electrophoresis (PFGE) genotyping. Four shared strains of Bifidobacterium breve (2), Bifidobacterium longum subsp. infantis and B. longum subsp. longum were found in breast milk-infant faeces pairs. Two years later, a second survey yielded four shared strains of the species Bifidobacterium adolescentis, Bifidobacterium bifidum, B. longum subsp. longum and Bifidobacterium pseudocatenulatum. Moreover, a B. bifidum strain was found to be shared by the infant faeces of the first study and the mother faeces tested two years later, pointing out a long term persistence. Some of the selected bifidobacterial strains showed probiotic potential due to their survival to gastrointestinal conditions and their ability to form biofilms.