Spiral arrangement of muscular elements in the walls of blood vessels and their role in hemodynamics

The article claims that contractions of the cardiac left ventricle produce a whirling (turbulent) movement of blood that is maintained in the aorta. In the walls of large and small arteries, as well as in the arteriolar walls, myocytes have a spiral arrangement. Their contraction maintains the turbulent blood stream in the vessels with a small diameter, in spite of the fact that the Reinolds' number for them is rather small. The author considers that while making a mathematical analysis of the blood flowing in the arteries, it is necessary to take into account that the walls of the arterial vessels actively influence the blood stream.     

Intralobular lymphatic vessels and their relationship to blood vessels in the mouse thymus

Summary The spatial distribution and fine structure of the lymphatic vessels within the thymic lobules of normal and hydrocortisone-injected mice were studied by light- and electron microscopy. The lymphatic vessels of the cortex and medulla of normal thymus are irregularly shaped spaces closely associated with branches of the intralobular artery and vein. The overall distribution of these vessels in the greatly involuted thymus of hydrocortisone-treated mice is essentially the same as in the normal thymus. The wall of the lymphatic vessels consists of only a layer of endothelial cells supported by underlying reticular cells. The luminal surface of the endothelial cell is smooth, but trabecular processes are often seen. There are three morphological types of intercellular contacts between contiguous cells, namely, end-to-end, overlapping and interdigitating. The lymphatic vessel has anchoring filaments and collagen fibrils, but a basal lamina is either absent, or if present, is discontinuous. This is in contrast to the continuous basal lamina of the venule. The perivascular space surrounding the postcapillary venule opens into a terminal lymphatic vessel at the cortico-medullary junction and in the medulla. Lymphocytes are seen penetrating the lymphatic endothelium, particularly in acutely involuted thymuses. These findings suggest that the intralobular lymphatic vessels may originate from the vacuities that surround the postcapillary venules, and the lymphatic system may function as a pathway for the migration of lymphocytes into or out of the lymphatic circulation.     

Effect of ergoline derivatives on platelet and blood vessels]

The influence of dihydrogenated ergot alkaloids on vessels and blood platelets was studied in vitro and in vivo. At low concentrations they cause contraction of isolated vein strips via a stimulation of alpha-adrenoceptors, at higher concentrations they antagonize the action of noradrenaline on arteries and veins and inhibit the adrenaline-induced platelet aggregation in vitro. In volunteers, intravenous and subcutaneous administration of dihydroergotamine (Dihytamin) caused a decrease in blood volume of the capacitance vessels and inhibition of the adrenaline-potentiated platelet aggregation "ex vivo". The selective venoconstrictor and antiaggregating effects of dihydroergotamine are utilized in the postoperative prophylaxis of thrombosis.     

"Teratologic series" and their genetics]

Isolated cyclopia is one of the members of the prosencephalic teratologic series. In some families with cyclopian monster other types of prosencephalic malformations are found in sibs or more distant relatives. All these malformations occur more frequently in females. Different forms of prosencephalies are observed in the same type of chromosome disbalance. These data suggest that morphogenesis and etiology of the prosencephalic malformations are common. Therefore a whole teratologic series but not a single member-malformation must be an object of genetic analysis. The same data are found for another teratologic series: bilateral renal agenesis--unilateral one--aplastic variant of the cystic dysplasia of kidneys. Polygenic inheritance with the threshold phenomenon is the most probable type of genetic determination of such malformations. The more frequent occurrence of polygenic malformations in families with the studied malformation whose inheritance is not yet established may be an indirect indication for the polygenic determination of the latter.     

Method for isolation of pancreatic blood vessels,their culture and coculture with islets of langerhans

The only cure available for Type 1 diabetes involves the transplantation of islets of Langerhans isolated from donor organs. However, success rates are relatively low. Disconnection from vasculature upon isolation and insufficient rate of revascularization upon transplantation are thought to be a major cause, as islet survival and function depend on extensive vascularization. Research has thus turned toward the development of pretransplantation culture techniques to enhance revascularization of islets, so far with limited success. With the aim to develop a technique to enhance islet revascularization, this work proposes a method to isolate and culture pancreas-derived blood vessels. Using a mild multistep digestion method, pancreatic blood vessels were retrieved from whole murine pancreata and cultured in collagen Type 1. After 8 days, 50% of tissue explants had formed anastomosed microvessels which extended up to 300 μm from the explant tissue and expressed endothelial cell marker CD31 but not ductal marker CK19. Cocultures with islets of Langerhans revealed survival of both tissues and insulin expression by islets up to 8 days post-embedding. Microvessels were frequently found to encapsulate islets, however no islet penetration could be detected. This study reports for the first time the isolation and culture of pancreatic blood vessels. The methods and results presented in this work provide a novel explant culture model for angiogenesis and tissue engineering research with relevance to islet biology. It opens the door for in vivo validation of the potential of these pancreatic blood vessel explants to improve islet transplantation therapies. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2745, 2019.     

Influence of muscular exercise on blood catecholamine levels in rats]

Lactacidemia, catecholaminemia and blood pressure have been measured in normal rats submitted to a swimming exercise. They are overloaded (6% body weight). Lactacidemia is increased after 15 minutes swimming. Adrenalinemia and noradrenalinemia are also statisticaly increased. Blood pressure falls during the exercice period. Hypotension is prevented by beta adrenergic blockade.     

Lymphatic and blood vessels of the liver in acute and chronic cholecystitis]

Changes in lymph and blood vessels were studied in 110 dogs with acute and chronic cholecystitis. It was established that in the period of development of acute inflammatory processes in the gall bladder the monolayer network of hepatic capillaries was changed into bi-layer, took place the formation of plane networks at the side of the lobule and lacunary dilatations in the site of fusion of lymph capillaries, dilatation and deformation of lymph capillaries and vessels. Under conditions of chronic cholecystitis fibrosis and sclerosis of the portal tracts were accompanied by intensive growth (and reduction - in parallel) of lymph capillaries. Thick small-looped network was observed to develop around false lobules during development of cyrrhosis. A conclusion is made that early cholecystectomy is necessary in cases of inflammatory diseases of the gallbladder.     

Anthropology and politics: The logic of their interrelationship

Conclusion The thesis of value neutrality is logically untenable and anthropologically naive. It is logically untenable because it does not attend to contextual (i.e. historical, sociological and political) meaning. It is anthropologically naive because it does not take into account that values are culturally mediated and historically situated, i.e. it assumes that values are the result of arbitrary choices. And, one must add, it is morally objectionable because it eliminates the notion of responsibility, though it pretends to defend it.Rather than attacking the thesis of value neutrality by following the more usual procedure of unmasking specific substantive theories, I have dismantled the logic of value neutrality itself by concentrating on the insurmountable formal contradictions of the fact-value dichotomy. In neglecting social, economic and cultural constraints, while stressing the freedom of the individual, the thesis of value neutrality emerges as liberal ideology. Whatever the liberating effect of decisionism may have been, it has de facto become the ideology of a scientific establishment which was conditioned to sell its services to the highest bidder. Decisionism has promoted a division of labor between those who determine the ends and those who supply the technical means without being concerned about their application . Thus it supports the status quo, and becomes a means of repression and exploitation .Decisionism is an inherent aspect of positivism . The subjectivity of ethics is the counterpart of the objectivity of science. Both are the result of a subjective idealism which takes the individual subject as point of departure. It is the individual subject who constructs his world on the basis of sensory impressions and his reason and who chooses his values. This implies not only the autonomy of ethics vis-à-vis science, but also an autonomy of facts vis-à-vis theory, and an autonomy of both science and ethics vis-à-vis history. This epistemological position is, therefore, elementaristic, individualistic and ahistorical.A radical alternative has to take as point of departure that cognition in its diverse manifestations (scientific and epistemological paradigms, logic, etc.) and value systems are interrelated historical products. It has to reject the compartmentalization of fact and value, fact and theory , subject and object, and it must place these relations in a truly dialectical perspective. Such a perspective does not provide us with unshakable moral and political precepts, but — since it does not take what is historically given for the eternally valid nor confound history with mere arbitrariness — it does point to the possibility and necessity of transformation and emancipation, i.e., the historically ly possible.Cornelis J.J. Vermeulen is Professor of Anthropology at the University of Amsterdam.

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Anthropology and politics: The logic of their interrelationship

Dialectical Anthropology - The thesis of value neutrality is logically untenable and anthropologically naive. It is logically untenable because it does not attend to contextual (i.e. historical,...     

Expression of metalloproteinases and their inhibitors in blood vessels in human endometrium.

Matrix metalloproteinases (MMPs) are zinc-requiring enzymes that can degrade components of the extracellular matrix and that are implicated in tissue remodeling. Their role in the onset of menstruation in vivo has been proven; however, the expression and functions of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in vascular structures are poorly understood. We determined by immunocytochemistry, using characterized monoclonal antibodies, the distribution of MMPs and of their inhibitors TIMP-1 and TIMP-2 in the endometrium during the menstrual cycle. MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, and TIMP-2 had differing distributions and patterns of expression. In addition to the localization of MMP-9 in the epithelium and of MMP-2, MMP-3, and MMP-1 in the stromal tissue, these MMPs were detected in the vascular structures. MMP-2 (72-kDa gelatinase) and tissue inhibitors TIMP-1 and TIMP-2 were detectable in vessels throughout the cycle. In contrast, MMP-3 (stromelysin-1) was detected only in late-secretory and menstrual endometrial vessels, while MMP-9 (92-kDa gelatinase) was detected in spiral arteries during the secretory phase and in vascular structures during the midfollicular and menstrual phases. The expression of MMP-2 and MMP-9 in endometrial vessels during the proliferative and secretory periods suggests their relationship to vascular growth and angiogenesis. The pronounced expression of MMP-3 (stromelysin-1) in the vessels situated in the superficial endometrial layer during menses suggests that this metalloproteinase initiates damage in the vascular wall during menstrual breakdown. The finding of an intense expression of TIMP-1 and TIMP-2 in the vessels delineating necrotic from non-necrotic areas during menses also suggests that they could limit tissue damage, allowing regeneration of the endometrium after menses. These data indicate that, in addition to expression in epithelial cells and stromal tissue, MMPs are expressed in endometrial vascular cells in a cycle-specific pattern, consistent with regulation by steroid hormones and with specific roles in the vascular remodeling processes occurring in the endometrium during the cycle.     

Human blood vessels created with tissue engineering

Progress in tissue engineering now allows the recreation of functional blood vessels from cultured human vascular cells. When reconstructed under specific conditions, their structure, mechanical properties and function (especially vasomotricity) allow them to be used as human models for studying the biology and pharmacology of blood vessels. These models may help to circumvent the limitations in the obtention and use of native human blood vessels for experimental purpose.