LYMPHATIC MICROVESSELS IN THE MYOCARDIUM: ARTIFACT OR OBJECTIVE REALITY?

Most of the current information on the lymphatic flow bed of the heart was obtained by the method of interstitial injection of various dyes, including the masses of Gerot. Low information content and numerous artifacts do not allow us to consider the data obtained by this method on lymphatic microvessels of myocardium reliable. The purpose of the work is to confirm or refute the data on the presence of lymphatic microvessels in the myocardium, using various methods for their detection. The vessels of the microvascular flow bed of the myocardium of intact experimental animals, rats (n = 7), cats (n = 3), rabbits (n = 3) was detected by the methods of Grant and Ranvier-Goyer in modification II. Markov. As a control, a universal method for the impregnation of argyrophilic structures was used. The data obtained give unambiguously reason to believe that there are no lymphatic microvessels in the myocardium of mammals.

Comparing the strengths and shortcomings of biomicroscopy and laser Doppler flowmetry (LDF) in the study of skin microcirculation

В статье анализируются преимущества и недостатки методов лазерной допплеровской флоуметрии и биомикроскопии при изучении микроциркуляции в кровеносных и лимфатических микрососудах кожи и др. органов. На конкретных примерах показаны широкие недостаточно используемые возможности биомикроскопии. The article analyzed merits and demerits of laser Doppler flowmetry and biomicroscopy in studying microcirculation in blood and lymphatic microvessels of the skin and other organs. Specific examples show wide, underutilized potentialities of biomicroscopy.

Conjunctival Lymphangiogenesis Was Associated with the Degree of Aggression in Substantial Recurrent Pterygia

Objective. To examine conjunctival lymphatic vessels and to analyze the relationship between lymphangiogenesis and aggressive recurrent pterygia.Methods. Tissues from 60 excised recurrent (including 19 of Grade 1, 28 of Grade 2, and 13 of Grade 3) pterygia were used in the study. Tissues from 9 nasal epibulbar conjunctivae segments were used as controls. Pterygium slices from each patient were immunostained with LYVE-1 monoclonal antibodies to identify lymphatic microvessels in order to calculate the lymphovascular area (LVA), the lymphatic microvessel density (LMD), and the lymphovascular luminal diameter (LVL). The relationship between lymphangiogenesis (LVA, LMD, and LVL) and pterygium aggression (width, extension, and area) was clarified.Results. Few LYVE-1 positive lymphatic vessels were found in the normal epibulbar conjunctiva segments. Lymphatic vessels were slightly increased in Grades 1 and 2 and were dramatically increased in Grade 3 recurrent pterygia. The LMD was correlated with the pterygium area in Grade 1 and 2 pterygia. In Grade 3, both LVA and LMD were significantly correlated with the pterygium area.Conclusions. Lymphangiogenesis was associated with the degree of aggression in recurrent pterygia, particularly in substantial Grade 3 recurrent pterygia.

Venomotion modulates lymphatic pumping in the bat wing

In skin, it is believed that lymph must be pumped by intrinsic contraction of lymphatic muscle, since investigators have not considered that cyclical dilation of venules could compress adjacent lymphatic microvessels. Because lymphatic vessels are sensitive to stretch, we hypothesized that venomotion not only can cause extrinsic pumping of lymph in nearby lymphatic vessels, but also can stimulate intrinsic contractions. Bat wing venules have pronounced venomotion and are in close proximity to lymphatic microvessels, and can be studied noninvasively without the confounding effects of anesthesia, surgical trauma, or contrast agents. Therefore, the interaction between venules and their paired lymphatic vessels in unanesthetized Pallid bats ( n = 8) was evaluated by recording the diameters of both vessels. Four sets of observations suggested that lymphatic and venous contractions were partially coupled. First, venous dilation and contraction produced a significant change in lymphatic microvascular cross-sectional area. Second, lymphatic microvascular contractions were immediately preceded by a change in venular diameter. Third, venular and lymphatic vessel contraction frequencies were positively correlated ( r = 0.75). Fourth, time delays between peak venular systole and onset of lymphatic microvascular contraction were negatively correlated with venomotion magnitude ( r = −0.55) and velocity ( r = −0.64). In a separate experiment, inhibiting venomotion resulted in a 54.3 ± 20.0% ( n = 8) decrease in lymphatic contraction frequency. Furthermore, 85.7% ( n = 56) of lymphatic vessels switch sides and lie adjacent to arterioles when venules were too small to exhibit venomotion. These results are consistent with both extrinsic pumping of lymph and stretch-induced lymphatic contraction and imply that intrinsic and extrinsic pumping can be coupled.