Blood Lactate Measurements and Analysis during Exercise: A Guide for Clinicians

Blood lactate concentration ([La⁻]_b) is one of the most often measured parameters during clinical exercise testing as well as during performance testing of athletes. While an elevated [La⁻]_b may be indicative of ischemia or hypoxemia, it may also be a “normal” physiological response to exertion. In response to “all-out” maximal exertion lasting 30-120 seconds, peak [La⁻]_b values of ≈15–25 mM may be observed 3–8 minutes postexercise. In response to progressive, incremental exercise, [La⁻]_b increases gradually at first and then more rapidly as the exercise becomes more intense. The work rate beyond which [La⁻]_b increases exponentially [the lactate threshold (LT)] is a better predictor of performance than V˙O2max and is a better indicator of exercise intensity than heart rate; thus LT (and other valid methods of describing this curvilinear [La⁻]_b response with a single point) is useful in prescribing exercise intensities for most diseased and nondiseased patients alike. H⁺-monocarboxylate cotransporters provide the primary of three routes by which La⁻ transport proceeds across the sarcolemma and red blood cell membrane. At rest and during most exercise conditions, whole blood [La⁻] values are on average 70% of the corresponding plasma [La⁻] values; thus when analyzing [La⁻]_b'', care should be taken to both (1) validate the [La⁻]_b-measuring instrument with the criterion/reference enzymatic method and (2) interpret the results correctly based on what is being measured (plasma or whole blood). Overall, it is advantageous for clinicians to have a thorough understanding of [La⁻]_b responses, blood La⁻ transport and distribution, and [La⁻]_b analysis.     

Localization of gastrointestinal bleeding from jejunal diverticuli by methylene blue dye

Localization of digestive hemorrhage is essential for the management of this entity. However, management is difficult in the small bowel, where emergency situations are rare but may require surgery without precise location of the lesion. We present a case of hemorrhage caused by jejunal diverticulum diagnosed by angiography. A highly selective microcatheter was placed in the bleeding site to achieve staining of the lesion with intraoperative methylene blue.     

CD3ζ Expression and T Cell Proliferation are Inhibited by TGF-β1 and IL-10 in Cervical Cancer Patients

Introduction  Cervical cancer development from a squamous intraepithelial lesion is thought to be favored by an impaired T cell immunity. We evaluated parameters of T cell alterations such as proliferation, cytokine, and CD3ζ expression in peripheral blood and tumor-infiltrating T lymphocytes from women with squamous intraepithelial lesions (SIL) or cervical cancer (CC). Results and Discussion  T cell proliferation and cytokine messenger RNA (mRNA) expression were similar in women with SIL and healthy donors, whereas low T cell proliferation and lower mRNA expression of IL-2, IL-10 and IFN-γ were observed in women with CC. Moreover, infiltrating cells showed marginal responses. We also found that CD3ζ mRNA expression, whose protein is required for T cell activation, correlated with a decreased proliferation in advanced stages of the disease. Conclusion  Experiments with T cells from healthy donors in the presence TGF-β1 or IL-10 suggest that these cytokines have a relevant role in T cell responses during CC progression.