Afferent Blood Vessels Research Articles

Comparison of the Safety Effects of Antiplatelets on the Kidneys in Patients with Vascular Disease

Aims: Most vascular disorders fall under the category of inflammatory diseases because they gradually harm blood vessels, disrupting the normal flow of blood to and from vital organs. The purpose of this research was to determine the potential dangers to kidney health associated with acetylsalicylic acid and clopidogrel treatment in patients with vascular diseases. Methodology: A cross-sectional research design was employed in the study, as well as retrospective data collection methods on medical records, and purposive sampling-based data sampling methodologies. Results: The study's findings indicated that there was no significant correlation between the use of antiplatelets and the risk of developing kidney disorders. It is rather, a patient's lifestyle, use of medications that increase the risk of renal GFR, and co-occurring diseases that may impair blood flow in the renal afferen can all increase their risk of developing a renal disorder with p-value <0.05. Nevertheless, the prolonged use of medication also plays a significant role in kidney function. The study's results indicate that renal problems are not attributed to the usage of antiplatelet drugs such as clopidogrel and acetylsalicylic acid. Scientific Novelty: Several using antiplatelet for indicated cardiovascular disease such us, atherosclerosis, plaque formation, endothelial dysfunction, and blockage or damage to the vascular endotelial matrix are all symptoms of vascular disease, a progressive inflammatory illness, it's frequently associated with the risk of kidney disorders. The use of antiplatelet will enlarge the afferent blood vessels. Conclusion: Instead, factors such as a patient's lifestyle, the severity of their condition, and their medical history could have a more significant impact on the likelihood of developing kidney dysfunction.

Adaptive morphogenesis of lamb liver under Anthropobiocenosis conditions lamb liver morphogenesis

Investigated the histological features of the structure of hepar of one-day-old lambs (ODL) using a complex of morphological techniques. It was found that hepar in ODL is formed by stroma and parenchyma. The stromal elements of the organ are formed by loose lugs of hematopoietic connective tissue, which in turn forms a capsule (2.80-7.23 microns thick), as well as the septa of the lobules, which include the hepar triads and paravasal tissue of efferent blood vessels. As a result of the studies, the prevalence of the stroma in the hematopoietic foci around large afferent blood vessels, especially in the hepar hilus, was revealed. The hepar parenchyma in ODL has structural incompleteness. It is formed by hepar cells and numerous resinusoidal cells located in the subcapsular, peripheral, central zones in the lobus hepatis. Hepar cells located in the subcapsular zone (SZ) have a more optically cleared (OC) cytoplasm, and the practically cleared cytoplasm of the hepatocyte diameter (HD) decreases towards the central zone (CZ). In the hepar parenchyma of the ODL, hematopoiesis foci (HF) are established in each of the lobes, which tend to decrease from the periphery to the center of the lobes. Hemopoetic cells (HC) are located between hepatocytes, densely layering on top of each other, and there are also cells located sparsely between the liver cells (LC). The number of hepatocytes per 1 mm2 of the area of the histological specimen in the left lobe (LL) of the ODL reaches the highest value 5983.79 ± 90.40, in the right lobe (RL) of the liver it is 5358.80 ± 646.60, while in the middle it has a minimum value and reaches 5133.10 ± 205.75.

Multiple stage treatment arteriovenous malformations rupture with intracerebral hematoma formations: a case report

This article describes a clinical case of arteriovenous malformation (AVM) associated with aneurism in a young woman. Its rupture caused intracerebral hematoma (ICH) in left parietal lobar of the brain. The initial condition of the patient was severe: coma, 5 scores by Glasgow Coma Scale and respiratory malfunction.Surgical therapy included microsurgical ICH evacuation with afferent blood vessel coagulation and ICP-sensor implantation, AVM embolization and autocranioplasty.Hemiplegia developed after the first microsurgical operation. At an early stage, antioxidants were included into the therapy complex. In twelve months the patient was still having local weakness in right foot, which didn`t disturb the movement (Glasgow Outcome Scale 5).

Vascular Canals in Permanent Hyaline Cartilage: Development, Corrosion of Nonmineralized Cartilage Matrix, and Removal of Matrix Degradation Products.

Core areas in voluminous pieces of permanent cartilage are metabolically supplied via vascular canals (VCs). We studied cartilage corrosion and removal of matrix degradation products during the development of VCs in nose and rib cartilage of piglets. Conventional staining methods were used for glycosaminoglycans, immunohistochemistry was performed to demonstrate collagens types I and II, laminin, Ki-67, von Willebrand factor, VEGF, macrophage marker MAC387, S-100 protein, MMPs -2,-9,-13,-14, and their inhibitors TIMP1 and TIMP2. VCs derived from connective tissue buds that bulged into cartilage matrix ("perichondrial papillae", PPs). Matrix was corroded at the tips of PPs or resulting VCs. Connective tissue stromata in PPs and VCs comprised an axial afferent blood vessel, peripherally located wide capillaries, fibroblasts, newly synthesized matrix, and residues of corroded cartilage matrix (collagen type II, acidic proteoglycans). Multinucleated chondroclasts were absent, and monocytes/macrophages were not seen outside the blood vessels. Vanishing acidity characterized areas of extracellular matrix degradation ("preresorptive layers"), from where the dismantled matrix components diffused out. Leached-out material stained in an identical manner to intact cartilage matrix. It was detected in the stroma and inside capillaries and associated downstream veins. We conclude that the delicate VCs are excavated by endothelial sprouts and fibroblasts, whilst chondroclasts are specialized to remove high volumes of mineralized cartilage. VCs leading into permanent cartilage can be formed by corrosion or inclusion, but most VCs comprise segments that have developed in either of these ways. Anat Rec, 300:1067-1082, 2017. © 2016 Wiley Periodicals, Inc.

Organization of the tentacular region in the vestimentiferan tubeworm Riftia pachyptila (Annelida, Vestimentifera)

Organization of the tentacular region in the giant vestimentiferan tubeworm Riftia pachyptila from hydrothermal vents has been reinvestigated. Protective cuticular structures consisting of a rod and a series of saucers have been found on the anterior surface of obturacula in juvenile individuals. This specific structural feature of juvenile R. pachyptila is regarded as a recapitulation of the ancestral state. The tentacular lamellae extend from the brain surface and run parallel to the body axis toward the anterior end of the tentacular region, which is similar to the structure of the tentacular apparatus in other vestimentiferan tubeworms. Its specific feature in R. pachyptila is the presence of vestimental extensions containing afferent and efferent blood vessels. Thus, differences in the structure of the tentacular region between R. pachyptila and other representatives of Tevniida are less than previously assumed, which allows R. pachyptila to be included in this group. It is considered that the specific structure of the tentacular region in R. pachyptila has developed as an adaptation allowing it to increase the number of tentacles.

Effect of Aerobic Training on Innervation Density and Neurogenic Responses of Skin Afferent Blood Vessels

We studied the effect of 8-week aerobic training (treadmill running) on neurogenic responses and density of sympathetic innervation of subcutaneous artery in rats. In trained rats, the artery response to stimulation of intramural sympathetic nerve decreased, but the sensitivity of vascular smooth muscles to norepinephrine was not changed. The density of adrenergic nerve fibers in the arterial wall after training was also lower than in the control group. This effect of training can be explained by the need in increased heat emission during physical activity.

Treatment of Angular Limb Deformities in Foals

Presently the approach to the treatment of angular limb deformities (ALD) is changing. While several years ago early recognition and early treatment was the aim, the recent trend goes more toward a selective approach. Immature foals with incomplete ossification of the precursor cartilage, best identified in the carpal and tarsal region are treated as early as possible with splints to facilitate ossification under even axial loads. Foals suffering from metaphyseal asymmetric growth but normal ossification are frequently observed for several months to allow to correct by themselves. In severe cases, meaning foals with deformities of greater than 12°, early treatment is proposed as well. Foals suffering from varus deformities of the metacarpophalangeal/metatarsophalangeal region should be treated before 1 month of age. The reason for this is the early closure of the physis at the approximate age of 3 months and in severe cases the development of an opposing valgus deformity within the proximal phalanx. Treatment techniques include growth acceleration, temporary unilateral growth retardation, and a combination thereof. The positive effect of hemicircumferential periosteal transection and stripping (HCPTS) was recently questioned, but in the mean time the pathway of the corrective mechanisms could be established with the help of molecular biology techniques. As a matter of fact, the experiments conducted to disprove the effect of HCPTS helped to clear up the mechanism. In a few words: the surgical insult near the shorter metaphyseal region upregulates Indian Hedge Hog (Ihh), which reach the physis via afferent blood vessels where they upregulate parathyroid hormones (PTH) and they accelerate the physeal growth locally. With the pathway cleared up, this technique regains part of its former popularity. Growth retardation can be achieved by several surgical techniques, which temporarily bridge the physis on the longer side of the bone until the shorter side has caught up. This type of management is proposed as state of the art in opposing valgus deformities of the proximal phalanx. Once the limb is straight the implants are removed. In bilateral deformities the implants in one limb may have to be removed before the other one. By waiting until the second limb is straight as well, the faster correcting one may have already overcorrected. Recently, radial extracorporal shock wave therapy has been introduced with apparently good results, to achieve a temporary growth retardation in a noninvasive manner. Once the physis is closed, angular limb deformities cannot be corrected any more through growth modulation. The only possible way is one type of corrective osteotomy or ostectomy.

Release of S100B Differs During Ischemia and Reperfusion of the Liver, the Gut, and the Kidney in Rats

S100B, an acknowledged marker of brain damage, is increased post-traumatically in plasma. The aim of this study was to investigate the diagnostic value of S100B release in experimental local extracranial ischemia and reperfusion. Anesthetized rats underwent laparotomy and ligation of the afferent blood vessels to the liver, gut, or kidney to achieve local ischemia in each organ separately. After 60 min of ischemia, ligatures were removed and resuscitation was performed for 3 h. S100B was determined in plasma by immunoluminometric assay 55, 65, and 240 min after the onset of ischemia (5 min before reperfusion and 5 min and 3 h after the onset of reperfusion). During ischemia of the liver, S100B increased before ligature removal and reperfusion, reaching significance early after the onset of reperfusion and remaining almost unchanged throughout reperfusion. In contrast, S100B did not increase during ischemia of the gut or kidney before ligature removal or during early reperfusion but increased significantly to similar levels as during reperfusion of the liver 240 min after the onset of ischemia (after 3 h of reperfusion). Our findings show for the first time that S100B increases during local extracranial ischemia and reperfusion. These experimental findings support the concept that brain damage is not necessarily the cause of increased S100B. Although S100B has been an acknowledged marker of brain damage for years, our experimental clinically relevant data indicate that S100B is, in fact, not specific as a marker of brain damage in the setting of local ischemia and reperfusion of the liver, gut, and kidney because local ischemia and reperfusion of these organs cause an S100B increase per se.

Beta 2-adrenergic receptor polymorphism and susceptibility to primary congenital and primary open angle glaucoma.

It has been shown that arginine to glycine (Arg16Gly), glutamine to glutamic acid (Gln27Glu) and threonine to isoleucine (Thr164Ile) exchanges in codons 16, 27 and 164, respectively, of the beta 2-adrenergic receptor (B2AR) gene significantly alter receptor function. As B2ARs are located on the afferent blood vessels supplying the ciliary body and trabecular meshwork cells, which control aqueous humour dynamics, polymorphisms of B2AR may be involved in the pathophysiology of certain eye diseases, such as glaucoma. Therefore, the aim of the present study was to investigate the distribution of B2AR polymorphisms in patients with primary congenital and primary open angle glaucoma. A group of 30 patients with primary congenital glaucoma, 105 with primary open angle glaucoma and 92 control patients were analysed for the Arg16Gly, Gln27Glu, and Thr164IIe polymorphisms of the B2AR by polymerase chain reaction-restriction fragment length polymorphism. The allelic frequencies of Gly16, Glu27 and IIe164 variant alleles were 66.7, 38.3 and 3.3% in patients with congenital glaucoma, 59.5, 31.0 and 1.0% with glaucoma, and 54.9, 26.6 and 0.5% in controls, respectively. Although statistically non-significant, the frequencies of variant alleles were slightly higher in both groups of the glaucoma patients. These results suggest no evidence of an association between the Arg16Gly, Glu27Gln and Thr164Ile polymorphisms of the B2AR gene and risk of developing primary open angle glaucoma or primary congenital glaucoma. However, further studies are needed to understand the role of B2AR polymorphisms in patients with eye disease.

Ultrastructure and small-subunit ribosomal DNA sequence of Henneguya lesteri n. sp. (Myxosporea), a parasite of sand whiting Sillago analis (Sillaginidae) from the coast of Queensland, Australia.

Henneguya lesteri n. sp. (Myxosporea) is described from sand whiting, Sillago analis, from the southern Queensland coast of Australia. H. lesteri displays a preference for the pseudobranchs and is typically positioned along the afferent blood vessels, displacing the adjoining lamellae and disrupting their normal array. The plasmodia appeared as whitish-hyaline, elliptical cysts (mean dimensions 230 x 410 microm) attached to the oral mucosa lining of the hyoid arch on the inner surface of the operculum. Infections of the gills were also found, in which the plasmodia were spherical, averaged 240 x 240 microm in size and were located on the inner hemibranch margin. The parasites lodged in the gill filament crypts and generated a mild hyperplastic response of the branchial epithelium. In histological sections, the plasmodium wall and adjoining ectoplasm appeared as a finely granulated, weakly eosinophilic layer. Ultrastructurally, this section of the host-parasite interface contained an intricate complex of pinocytotic channels. H. lesteri is polysporic, disporoblastic and pansporoblast forming. Sporogenesis is asynchronous, with the earliest developmental stages aligned predominantly along the plasmodium periphery, and maturing sporoblasts and spores toward the center. Ultrastructural details of sporoblast and spore development are in agreement with previously described myxosporeans. The mature spore is drop-shaped, length (mean) 9.1 microm, width 4.7 microm, thickness 2.5 pm, and comprises 2 polar capsules positioned closely together, a binucleated sporoplasm and a caudal process of 12.6 microm. The polar capsules are elongated, 3.2 x 1.6 microm, with 4 turns of the polar filament. Mean length of the everted filament is 23.2 pm. Few studies have analyzed the 18S gene of marine Myxosporea. In fact, H. lesteri is the first marine species of Henneguya to be characterized at the molecular level: we determined 1966 bp of the small-subunit (18S) rDNA. The results indicated that differences between this and the hitherto studied freshwater Henneguya species are greater than differences among the freshwater Henneguya species.

A MORPHOLOGIC STUDY OF THE VASCULATURE OF MALIGNANT GLIOMAS USING THICK CELLOIDIN SECTIONS AND ALKALINE PHOSPHATASE STAIN

The combination of 100 microm thick celloidin sections and alkaline phosphatase (AP) enzyme histochemistry of the vascular endothelium offers a greatly enhanced, 3D morphologic perspective and reveals intricate details of the vasculature of brain. A study of tumor specimens obtained at craniotomy from 6 patients with glioblastomas, 1 with anaplastic oligodendroglioma and 1 with juvenile pilocytic astrocytoma was undertaken using this technique. Five of the 6 glioblastomas, the anaplastic oligodendroglioma and the low-grade astrocytoma specimen showed uniform staining of afferent tumor blood vessels. In the glioblastomas, newly formed vessels formed dense, festooned networks at the advancing edges of the tumor. Feeding arteries entered the tumor at the junction between the edge of the tumor and adjacent brain or meninges and proceeded to form striking, coiled vessels and smaller branches. The density of both small arteries and veins was greatly increased within the tumor although there was much variability. Disordered arborization, arteriole to venous and arteriole to arteriole shunts were observed, leading to a situation where arteries connected directly to veins. In necrotic areas, there were often no AP-stained vessels. In many places, arterioles and capillaries were lacking. Numerous AP-negative veins of various sizes drained the tumors. Glomeruloid proliferations were presumptively identified as focal stain smudges or clusters of capillaries arising from nearby vascular channels. Increased alkaline phosphatase staining and/or focal new vessels were seen outside necrotic areas. The pilocytic astrocytoma and the oligodendroglioma showed less dense vascularity and no formation of the focal festoons of vessels shown by the glioblastomas. This technique may be useful for the study of tumor angiogenesis and to evaluate vascularity in experimental and human brain tumors after various therapies.

Specialized Ion-Transporting Epithelium around the Blood Vessel of the Coxal Gills in a Deep-Sea Amphipod, Eurythenes gryllus

ABSTRACT Histological examination showed that the deep-sea amphipod Eurythenes gryllus possesses a unique tissue area around the afferent blood vessel of the gill, which exhibits well-developed infoldings of the basolateral cell membrane with many mitochondria. The location (i.e., around the afferent blood vessel) and the above ultrastructural characteristics indicate that this unique tissue is homologous with a type of osmoregulatory tissue which was described for the patchlike area of gills in two estuarine amphipods Grandidierella japonica and Melita setiflagella. We review the presence/absence of this specialized tissue for 12 species (including the above 3 species) belonging to 8 genera collected from deep-sea, coastal, brackish, supralittoral, and fresh-water areas. All but Sternomoerajaponica, the distribution of which is limited to fresh-water seepage flows in forests, possessed the tissue. The discovery of the specialized tissue in E. gryllus confirms the widespread occurrence of the tissue in amphipod species.

A scanning electron microscope study of the luminal surface specializations in the blood vessels of the pecten oculi in a diurnal bird, the black kite ( Milvus migrans)

The luminal surface of the pecten oculi of the black kite (Milvus migrans), a diurnally active bird of prey, was examined by scanning electron microscopy. In this species the blood vessels are generally of two types, the small-calibre capillaries and the large-calibre afferent and efferent vessels. The luminal surface of the efferent blood vessels possesses a few low microplicae. Conversely, the luminal surface of the afferent blood vessels is characteristically smooth except at the cell junctions and at the point of entry into the capillaries. The cells junctions are marked by low ragged ridges while the luminal surface is studded with low sparse pleiomorphic microprojections at the point of capillary emergence. The luminal surface of the blood capillaries is characterised by a labyrinth of closely disposed microplicae that projects into the lumen. These microplicae show no particular orientation with respect to either the longitudinal or transverse axis of the capillary. Instead, they are diffusely orientated. It is conjectured that such a heterogeneous design of the endothelium in the blood vessels of the pecten oculi has developed in order to augment the role of the pecten in the transport of nutrients to the avascular neural retina by an energy saving diffusion process. The process through which the design of the microfolds affects haemodynamics and their putatite role in facilitating the delivery of nutrients are discussed in the perspective of the available data.

SPECIALIZED ION-TRANSPORTING EPITHELIUM AROUND THE BLOOD VESSEL OF THE COXAL GILLS IN A DEEP-SEA AMPHIPOD, EURYTHENES GRYLLUS

Histological examination showed that the deep-sea amphipod Eurythenes gryllus possesses a unique tissue area around the afferent blood vessel of the gill, which exhibits well-developed infoldings of the basolateral cell membrane with many mitochondria. The location (i.e., around the afferent blood vessel) and the above ultrastructural characteristics indicate that this unique tissue is homologous with a type of osmoregulatory tissue which was described for the patchlike area of gills in two estuarine amphipods Grandidierella japonica and Melita setiflagella. We review the presence/absence of this specialized tissue for 12 species (including the above 3 species) belonging to 8 genera collected from deep-sea, coastal, brackish, supralittoral, and fresh-water areas. All but Sternomoera japonica, the distribution of which is limited to fresh-water seepage flows in forests, possessed the tissue. The discovery of the specialized tissue in E. gryllus confirms the widespread occurrence of the tissue in amphipod species.

CO2 transport in catheterized hydrothermal vent tubeworms, Riftia pachyptila (vestimentifera)

AbstractIsolated plumes and vestimenta of the tubeworm Riftia pachyptila were perfused to determine the form in which carbon is transported to the animal's symbionts via the circulatory system. Catheters supplying colored saline were inserted into an afferent blood vessel while samples were collected from the efferent vessel. During perfusion, the plumes were immersed in sea water containing radiolabeled CO2. The effluent showed radioactivity in inorganic carbonate (∑ CO2, sum of all forms), malate, and succinate. When isolated vestimenta were perfused with saline containing labeled CO2, labeled malate and succinate could be detected in the effluent. Carbon transport in the blood as ∑ CO2 is estimated to be of similar importance to that transported after incorporation into organic carbon. The significance for the establishment of the carbon isotope ratio of tubeworms is discussed. © 1995 Wiley‐Liss, Inc.

Pulmonary infarction: sonographic appearance with pathologic correlation

Objective: Peripheral pulmonary lesions are detectable by ultrasound, the aim of this study was to compare sonograms of pulmonary infarctions with their pathological reports. Subjective: A total of 26 lung infarcts in 15 non-fixed autopsy lungs of patients showing necroscopically pulmonary embolism were examined sonographically in a water-bath no later than 5 h after autopsy with a 5- or 7.5-MHz sector scanner. Five of these patients were suspected of pulmonary embolism and underwent sonographic examinations shortly before their death. Results: Ultrasound showed mainly wedge-shaped ( n = 18), hypoechoic areas. Their location, form and size corresponded exactly with pathological findings. Fresh infarcts were homogeneous and more hypoechoic. Older infarcts were well demarcated and showed a hyperechoic reflex in the center corresponding to the bronchiole; this was a sign of segmental involvement. In two cases it was possible to differentiate thromboembolically congested afferent blood vessel directed to the hilus. Ultrasound images from five living patients were similar to the image of the autopsy lung. Conclusion: In accordance with clinical studies these observations suggest that transthoracic sonography can be an efficient technique in the detection of pulmonary infarction, as well in an early reperfusionable stage as in distinguished infarct formation.

Protective Effect of the Calcium Channel Blocker Diltiazem on Hepatic Function Following Warm Ischemia

The purpose of this study was to investigate the protective effect of a calcium channel blocker diltiazem (DTZ) on hepatic ischemic injury using a canine model. Hepatic ischemia was induced by temporary clamping of hepatic afferent blood vessels for 60 min with establishment of a portojugular bypass. The administration of DTZ at a dose of 70 μg/kg bolus iv injection before hepatic ischemia and thereafter via the portal vein at a dose of 10 μg/kg/min well restored the hepatic blood flow (HBF, 92 ± 5%; P < 0.01) and arterial ketone body ratio (AKBR, 1.15 ± 0.16; P < 0.01) 1 hr after interruption compared with untreated controls (HBF, 61 ± 7%; AKBR, 0.53 ± 0.09). In addition, the increase of plasma lactate level and the decrease of mean arterial pressure were significantly suppressed after ischemia ( P < 0.05). We concluded that DTZ has a protective effect on ischemia-induced hepatic damage and might be useful in the prevention of primary graft failure caused by warm ischemia in liver transplantation.

The osmoregulatory tissue around the afferent blood vessels of the coxal gills in the estuarine amphipods, Grandidierella japonica and Melita setiflagella

By electron microscopy of the coxal gills in two species of estuarine amphipod crustaceans, Grandidierella japonica and Melita satifragella, we found a patch-like, specialized tissue area which consisted of unique cells closely resembling the salt-excreting cells in the gill of the brine shrimp and so-called chloride cells in teleost gills. These cells were characterized by an abundance of mitochondria, two kinds of extensive networks of cytoplasmic tubules, well-developed lamellar infoldings of the basal cell membrane, sparse microvillous projections of the apical border, and numerous large vacuoles with several incomplete partitions. The large (60 nm in diameter) and the small (30 nm) cytoplasmic tubular networks were found in the basal and the apical portions of the cell, respectively. The large networks, which were both directly and indirectly (through the lamellar system) continuous with the basal cell membrane, were regarded as extensions of the cell membrane. Both the outer walls and the partition walls of the vacuoles were reinforced with a parallel array of microtubules. The results suggest that this unique tissue plays an important role in the active transport of electrolytes to maintain a constant osmotic pressure of the hemolymph under widely fluctuating salinities of the estuarine environments.

Detection of focal nodular hyperplasia of the liver with color Doppler ultrasonography

A 3-cm lesion indicative of focal nodular hyperplasia (FNH) of the liver was coincidentally detected in a 21-year-old female. Ultrasonography (US), computed tomography (CT), magnetic resonance (MR) imaging and liver scintigraphy all proved nonspecific. However, color Doppler US demonstrated characteristic vascular patterns of FNH of the liver, including (a) hypervascularity of the mass, (b) an enlarged afferent blood vessel in the tumor with blood flow toward the center of the tumor, and (c) arterial pulse waves in all the vessels in the lesion, detected by means of the fast Fourier transformation (FFT). With selective hepatic angiography, a "spoke-wheel" pattern was revealed. The angiographic pattern corresponded well to that shown by color Doppler US. On the basis of the findings from these two modalities, the diagnosis of FNH was made. This report examines the effectiveness of color Doppler US in the differential diagnosis of FNH, compared with other imaging modalities.

Studies on the vasculogenesis in rat cerebral cortex.

The cerebral cortices are nourished by blood circulating through a capillary network branching from parent arteries. In this paper, vasculogenesis of the cerebral cortices in developing rats (11-18 days after birth) was studied by light and electron microscopy after intravenous administration of horseradish peroxidase (HRP). In the first phase of vasculogenesis, tentacles grew out from the distal end of the vascular cord (tip cells), and in the second phase, they extended to the afferent blood vessel. The reaction product of HRP was distributed not only in the primitive vascular lumen, but also in the peripheral extravascular space of the vascular cord. Most tentacles were free from reaction product, but, in some cases where reaction product was detected, the intercellular spaces had spread into the tip cells and reached the root of the tentacles. After the tentacles contacted the afferent vascular cord, the two vascular cords approached and fused with each other. Blood serum was able to circulate between the two vascular cords via the irregular interstices formed among the endothelial cells, cytoplasmic processes, and tentacles. Later, the primitive vascular lumen developed to a sufficient size to allow for the circulation of blood cells. The sequential events in the process of fusion between two vascular cords are illustrated. The following two points were also noticed in this study: 1) during cerebral vasculogenesis, degeneration and vacuolization in primitive endothelial cells occurred only in some of the serial sections and did not play a significant role in the formation of vascular lumen, and 2) cerebral pericytal macrophages (CPM) (classified as fluorescent granular perithelial cells by the authors) appeared close to the vascular cord, although the biological meaning of it remained unknown in the present investigation.