Panjit Chunhabundit

SEM study on the dorsal lingual surface of the common tree shrew, Tupaia glis.

The dorsal lingual surface of the common tree shrew was examined by SEM after treating it with HCl to remove the mucous substance. Filiform (FI), fungiform (FU) and circumvallate papillae (CI) were observed. The FI exhibited a small circular bulge surrounded by anterior and posterior filamentous processes. FU were scattered among the FI. There were 3 CI separating the anterior 4/5 from the posterior 1/5 of the tongue. In addition, a group of conical projections with caudal orientation was found anterior to the palatoglossal fold on each side of the tongue. Microridges were widely observed on the entire dorsal lingual surface, except on the free surface of FI processes.

Scanning electron microscopic study on pineal vascularization of the common tree shrew (Tupaia glis)

Chunhabundit P, Somana R. Scanning electron microscopic study on pineal vascularization of the common tree shrew (Tupaia glis). J Pineal Res 1991 : 1059‐64.

Microvasculature of the thyroid gland in the common tree shrew (Tupaia glis): microvascular corrosion cast/scanning electron microscopy study.

A thyroid vascular cast of the common tree shrew (Tupaia glis) was obtained by injection of Batsons No. 17 plastic mixture into the ascending aorta. The cast was studied under the scanning electron microscope. It was found that each half of the gland is supplied by a large superior and a rather small inferior thyroid artery. After plunging into the gland, the arteries divide into smaller branches that are the interlobular, intralobular and follicular arteries (afferent vessels). The basket-like capillaries arising from the follicular arteries and encapsulating thyroid follicles are of large diameter and are arranged in a single layer. The follicular side of the capillary casts was observed to contain numerous small and some large projecting knobs compatible with the presence of fenestrations in the endothelial cells. On the other hand, endothelial nuclear imprints were found mainly on the stromal surface of the follicular capillary casts. Transfollicular capillaries connecting the adjacent follicular capillary networks were also observed. Blood from the follicular capillaries either drains into the follicular veins (efferent vessels) or abruptly drains into the intralobular veins before proceeding to intralobular and interlobular veins, respectively. The interlobular veins are collected into a few small superior, a few larger middle and a few even larger inferior thyroid veins. These veins drain directly into the laryngeal vein lying adjacent to the deep surface of the thyroid gland before joining the jugular vein. Venous valves were identified outside the thyroid gland. In addition, the glomerular capillary island of the parathyroid gland was often seen at the cranioanterolateral and sometimes at the cranioposterolateral aspect of the thyroid gland.

Microvascularization of the Rat Superior Cervical Ganglion

The three-dimensional image of the microvascularization of the rat superior cervical ganglion (SCG) was examined using the vascular corrosion cast technique in conjunction with scanning electron microscopy. It was found that the rat SCG was a highly vascularized organ. Arteries supplying the ganglion gave rise to a subcapsular capillary plexus before branching off to become intraganglionic capillaries. Two types of intraganglionic capillaries, large and small, were observed throughout the organ. Numerous anastomoses among these capillaries were found before they converged into venules and collecting veins. However, a pattern of blood vessels resembling portal-like intraganglionic microcirculation could not be demonstrated.

Angioarchitecture of the coeliac sympathetic ganglion complex in the common tree shrew ( Tupaia glis )

The angioarchitecture of the coeliac sympathetic ganglion complex (CGC) of the common tree shrew (Tupaia glis) was studied by the vascular corrosion cast technique in conjunction with scanning electron microscopy. The CGC of the tree shrew was found to be a highly vascularised organ. It normally received arterial blood supply from branches of the inferior phrenic, superior suprarenal and inferior suprarenal arteries and of the abdominal aorta. In some animals, its blood supply was also derived from branches of the middle suprarenal arteries, coeliac artery, superior mesenteric artery and lumbar arteries. These arteries penetrated the ganglion at variable points and in slightly different patterns. They gave off peripheral branches to form a subcapsular capillary plexus while their main trunks traversed deeply into the inner part before branching into the densely packed intraganglionic capillary networks. The capillaries merged to form venules before draining into collecting veins at the peripheral region of the ganglion complex. Finally, the veins coursed to the dorsal aspect of the ganglion to drain into the renal and inferior phrenic veins and the inferior vena cava. The capillaries on the coeliac ganglion complex do not possess fenestrations.

Scanning electron microscopic study of the splenic vascular casts in common tree shrew (Tupaia glis)

SummarySplenic vascular casts of the common tree shrew,Tupaia glis, were constructed with Batsons No. 17 plastic mixture and studied with the scanning electron microscope (SEM). Fifteen adult animals of both sexes, weighing between 120 and 180 g were used. Under ether anaesthesia, each animal was injected with 0.05 ml heparin intracardially; the right atrium was cut open and then 250 ml of 0.9% NaCl, followed by 50 ml of 10% neutral formalin, (in four animals) was injected through the left ventricle. Plastic mixture was injected through the same opening. After complete polymerization of the plastic, the spleen and surrounding tissues were removed and macerated in 40% KOH. The air-dried casts were then coated with carbon and gold before viewing and photographing under SEM at 15 kV. It was found that the splenic arteries penetrated deep into the organ before they divided into trabecular arteries and divided again into central arterioles. Each central arteriole sent out 15 to 30 radiating arterioles, called penicillar arterioles, and further divided into smaller vessels entering the marginal zone and red pulp. In this area each arteriole continued directly into either marginal or red pulp sinusoids. The sinusoids emptied into pulp venules which joined to form trabecular veins. Most of the trabecular veins travelled to the cortical area underneath the splenic capsule before approaching the hilum, where they finally drained into splenic and short gastric veins. It is likely that the spleen of the common tree shrew has a closed circulation.

Testicular microvascularization in the common tree shrew (Tupaia glis) as revealed by vascular corrosion cast/SEM and by TEM.

Testicular angioarchitecture in lower primates has not been established and the route of androgens from Leydig cells entering the systemic circulation is still a matter of controversy. In the present study, the common tree shrew (Tupaia glis) was used as the model for vascular corrosion cast/SEM and conventional TEM studies. With vascular corrosion cast/SEM, it was revealed that while coursing in the spermatic cord, the testicular artery convoluted and gave off branches to supply the epididymis, the coverings of the spermatic cord and the pampiniform plexus. Upon approaching the testis, it encircled the organ, then penetrated into the testicular parenchyma near the rostro‐medial pole before further dividing into arterioles that gave rise to capillary plexuses looping around the seminiferous tubules. These capillaries converged into the intratesticular venules, then into larger venules on ventral and dorsal surfaces of the testis and finally into the collecting veins on medial and lateral borders of the testis. In addition, the capillaries in the central or medullary portion of the gland collected the blood into the medullary venules and central (medullary) vein, respectively. The collecting veins as well as central vein joined together before dividing into pampiniform plexus. With transmission electron microscopy, the capillaries in the testis were shown to be of the thick basement membrane and continuous type. The Leydig cells were found adjacent to lymphatic vessels among the seminiferous tubules. This structure is compatible with the idea that most of the androgens drain into the lymphatic vessels rather than into the capillaries. Microsc. Res. Tech. 42:226–233, 1998.

Microvascularization of the Common Tree Shrew (Tupaia glis) Superior Cervical Ganglion Studied by Vascular Corrosion Cast with Scanning Electron Microscopy

Microvascularization of the superior cervical ganglion (SCG) of the common tree shrew (Tupaia glis) was investigated by the vascular-corrosion-cast technique in conjunction with scanning electron microscopy. It was found that the SCG of the tree shrew is a highly vascularized organ. It receives arterial blood from branches of the external and common carotid arteries which enter the rostral and caudal portions of the ganglion. These arteries give rise to a subcapsular capillary plexus before branching off to form a group of densely packed intraganglionic capillaries. Moreover, the intraganglionic capillaries tend to follow a tortuous course that is essentially parallel to the longitudinal axis of the ganglion, and they form anastomoses with each other. In addition, the intraganglionic capillaries are also connected to a subcapsular capillary plexus. The capillaries of the SCG converge into venules and collecting veins which subsequently drain rostrally and caudally into the systemic veins. However, neither a pattern of blood vessels resembling glomeruli nor a portal-like intraganglionic microcirculation was observed.

Pancreatic Microcirculation in the Common Tree Shrew (Tupaia glis) as Revealed by Scanning Electron Microscopy of Vascular Corrosion Casts

Pancreatic vascular casts of the common tree shrew (Tupaia glis) were prepared by infusion of Batsons No. 17 plastic mixture into the blood vessels and examined by scanning electron microscopy (SEM). Routine histological study of the pancreas was also performed. It was found that the A and D cells appeared to occupy the core whereas the B cells were found at the periphery of the islets of Langerhans. With SEM, the insular arteriole, a branch of the interlobular artery, was shown to penetrate deeply into the core of the islets before branching off into the glomerular capillary network supplying the islets. These capillaries reunited at the periphery of the islets to become vasa efferentia and then gave off capillaries to anastomose with those in the exocrine part of the pancreas, the insuloacinar portal system. Such an insuloacinar portal system found in the pancreas of the tree shrew was similar to that found in the horse and monkey. However, there were some intralobular arterioles which did not end in the islets but directly branched into the interacinar capillary network and periductular plexus. The capillaries in the exocrine part not only gathered into intralobular venules which confluently formed the interlobular vein but also supplied the duct system. The periductular plexus also collected blood into the intralobular venule and interlobular vein, respectively.

Adrenal Microvascularization in the Common Tree Shrew (Tupaia glis) as Revealed by Scanning Electron Microscopy of Vascular Corrosion Casts

The blood supply of the adrenal gland in the common tree shrew (Tupaia glis) was studied by use of transmission electron microscopy and vascular corrosion cast/scanning electron microscopy techniques. It was found that the gland receives its blood supply from branches of the inferior phrenic, aorta and renal arteries. Upon reaching the gland, these arteries divide into cortical and medullary arteries. The cortical arteries give rise to the subcapsular capillary plexuses which partially enclose the clusters of cells in the zona glomerulosa (ZG) and appear as lobular-like microvascular networks before running among the cellular cords in the zona fasciculata (ZF) and zona reticularis (ZR). It was noted that the capillaries in ZG and ZR are with more anastomoses than those in the ZF. Capillaries from the ZR become the sinusoidal capillaries in the adrenal medulla before proceeding to the peripheral radicles of the central vein. The medullary arteries penetrate the adrenal cortex and occasionally give off small branches to supply the inner cortex, especially the ZR. Their main branches break up into small or conventional capillaries in the adrenal medulla. These capillaries drain the blood into the peripheral radicles of the central vein and medullary collecting veins which proceed further into a very large central vein. The present findings illustrate that the adrenal medulla receives two blood supplies that yield somewhat different influences upon the adrenal medulla. The portal blood vessel could not be illustrated in the tree shrew adrenal gland.