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PubMed1980

The development of the sinusoids of fetal rat liver: morphology of endothelial cells, Kupffer cells, and the transmural migration of blood cells into the sinusoids.

The fine structural development of rat fetal liver sinusoids from 10 to 22 days gestation was studied. Colloidal carbon (Pelikan ink) was injected into 14-22 day gestation fetuses via the umbilical vein to assess the continuity of the sinusoidal lining and the phagocytic ability of the developing lining cells. Endothelial cells, devoid of an underlying basal lamina, form the bulk of the vascular lining at all gestational ages. These cells possess typical intercellular junctions and fenestrae with diaphragms before 17 days gestation. Transendothelial open fenestrations, typical of the adult liver, appear around 17 days gestation, increasing in number for the remainder of gestation. Although fenestrae possessing diaphragms are permeable to carbon before 16 days gestation, open fenestrations, first seen at 17 days gestation, allowed large amounts of carbon to reach the extravascular space. Endocytosis of carbon by endothelial cells was accomplished exclusively by large bristle-coated vesicles. Endothelial cells were also seen to be involved in transmural diapedesis of newly formed erythrocytes and megakaryocyte processes from the extravascular space by forming a temporary migration pore allowing these cells and processes to enter the circulation. At the end of gestation, blood-forming activity had nearly ceased, and only the space of Dissé separated the lining cells from the parenchymal cells. Kupffer cells were easily identified as early as 13 days gestation by their content of phagosomes and engulfed erythrocytes. The Kupffer cells are much more avid in the phagocytosis of carbon than are endothelial cells. Toward the end of gestation, some Kupffer cells develop a homogeneous "sticky coat" to carbon.

Animals↗

PubMed1987

Effect of neural crest ablation on development of the heart and arch arteries in the chick.

Mesenchymal derivatives of the neural crest contribute to the connective tissues and blood vessels of the pharyngeal arches, and participate in the septation of the outflow tract of the heart. The present study was designed to determine the nature and timing of alterations in the development of the heart and arch arteries subsequent to diminished neural crest contributions. The neural crest contributing to the three caudalmost pharyngeal arches was ablated bilaterally in chick embryos and compared with sham or unoperated controls. Heart development was studied by scanning electron microscopy. Arch artery development was studied microscopically after intravascular injection of India ink and clearing of the specimen. Neural crest ablation caused morphological changes in most hearts. Hearts in experimental animals commonly were elongate and were subject to inappropriate development of ventricular and atrial areas. A surgical effect delayed the disappearance of arch arteries one and two, and removal of neural crest produced an additional delay. Neural crest ablation caused failure of arch arteries three, four (right), and six to develop to the proper size in some animals. Survival of those whose sixth arch arteries achieved the proper size caused group measurements to reach normal values again by stage 32. Closure of arch arteries in some animals and maintenance in others produced greater variability in experimental animals than in controls. It is significant that heart morphology was altered before septation of the outflow tract normally occurs. This indicates at the least that another factor, such as altered blood flow, contributes to the abnormal development. Altered flow may result from changes in pharyngeal arch mesenchyme and arch artery endothelium.

Animals↗

PubMed1988

Microvascular networks in tympanic membrane, malleus periosteum, and annulus perichondrium of neonatal mongrel dog: a vasculoanatomic model for surgical considerations.

India-ink-imaged blood-vessel networks in cleared tympanic membranes and adnexa from ten neonatal dogs were examined microscopically and photographed. The major significance of the study lies in documentation of a dual source of arterial supply, a bilaminar relationship of arterial and venous plexuses intrinsic to the tympanic membrane, and a consistent major venous pathway relative to a definite locus (pars flaccida of the membrane). Illustration of all three types of blood pathways (arteries, veins, and capillaries) provides new vasculoanatomic data that are essential to ear surgery, specifically--to myringotomies and myringoplasties. A comparison was made between dog and human tympanic membrane structures and their arterial supplies. Close similarities suggested that dog tympanic membrane might serve as a suitable model for development of innovative surgical procedures and as a model for rehearsal of difficult techniques. The results of this investigation provide a valuable caveat to otologists.

Animals↗

PubMed1990

Origin of the proximal coronary artery stems and a review of ventricular vascularization in the chick embryo.

The objective of this study was to determine how the coronary artery stems develop in the chick embryo. The hearts of 51 ink-injected and cleared chick embryos, aged embryonic days 6, 6.5, 7, 7.5, 9, and 10, were dissected, examined, and selectively photographed. Two representative hearts from each group were paraffin embedded, serially sectioned at 10 microns, and examined for aortic endothelial budding. We found that the proximal coronary artery did not appear to grow outward from the aorta as commonly described in the literature. It appeared to originate from a capillary ring which encircled the aortic and pulmonary outflow tracts. On embryonic day 7.5, one to three channels arising from this ring penetrated each aortic sinus, in an area of darker textured endothelium. Histologically and grossly, multiple channels were still apparent on day 9, particularly in the left coronary artery. One of these channels always became dominant to form the stem. Each stem, which varied in length from embryo to embryo, always ended in a plexus of sinusoidal endothelial tubes. By day 10, the coronary artery stems were longer, with many major branches. Histologically, evidence of multiple channels still was visible. It is significant that channels from the bulbar vascular ring penetrated the aorta at very specific points in the aortic sinuses and did not penetrate the pulmonary trunk or other aortic sites. We believe this fact indicates that the penetration of the aortic sinuses by channels from the bulbar vascular ring represents a controlled invasion of the aorta.

Animals↗

PubMed1995

Blood vessel formation in the avian limb bud involves angioblastic and angiotrophic growth.

The vasculature of the avian limb bud takes its origin from the intersomitic vessels as can be shown by ink perfusion of the embryo. While the primitive vessels form a central network in the early limb bud, an area of about 100 microns in width from the ectoderm inward remains free from lumenized vessels. However, this subectodermal avascular zone contains isolated angioblasts, which can be demonstrated by confocal laser scanning microscopy in connection with QH-1-staining. QH-1-positive cells from the avascular zone are capable of giving rise to endothelial cells when grafted ectopically into a "permissive" environment such as the dorso-lateral paraxial mesoderm. Several grafting sites are compared regarding their permissiveness for capillary formation. In order to investigate the origin of the QH-1-positive angioblasts we carried out injections of DiI-Ac-LDL, which is specifically taken up by endothelial cells and macrophages, and found the lumenized vessels and a few isolated cells in the peripheral limb mesoderm stained. In double-labelling studies combining DiI-Ac-LDL and QH-1, it can be shown that there exists a pool of isolated angioblasts that are only QH-1-positive, but have not incorporated DiI-Ac-LDL. In contrast to the lumenized vessels in the core of the limb bud, we found that angioblasts in the avascular zone do not proliferate, as shown by proliferation studies applying the BrdU-method to semithin sections in connection with QH-1-labelled parallel sections. We conclude that the vascularization of the avian limb bud is achieved by a combination of angiotrophic growth (sprouting of vessels) and angioblastic growth (recruitment of angioblasts from the limb mesoderm.

Animals↗

PubMed1995

Neurobehavioral effects of acute and chronic mixed-solvent exposure in the screen printing industry.

This 2-year prospective study examined the neurobehavioral effects of acute and chronic exposure to mixed solvents in workers in a screen printing business. A total of 30 subjects participated in the study in two field testings over a 12 month period. Each subject completed a detailed medical and occupational questionnaire, had a neurological examination, and underwent a battery of neuropsychological tests. Industrial hygiene investigation identified the following chemical exposures as present: toluene, methyl ethyl ketone, mineral spirits, beta-ether, methylene chloride, and acetic acid. Different departments and jobs had varying degrees of exposure to these chemicals, the highest exposures being in the ink mix area and the screen washroom area. However, all exposure levels were below recommended threshold limit values. Persons categorized as having higher acute exposure demonstrated significantly impaired test performance on tasks involving manual dexterity, visual memory, and mood. Those with higher chronic exposure demonstrated significantly poorer performance on visual memory tasks and mood. Results suggest that the mixed solvents used in the screen printing industry have an effect on central nervous system functioning in the absence of obvious clinical disease.

Adult↗

PubMed1992

Can we really walk straight?

Twenty healthy men were asked to walk as straight as possible to a target 60 m away at normal speed. A series of footprints was recorded for each subject by having him wear socks soaked with red ink and walk on white paper fixed flat to the floor. Fourier analysis was applied to determine whether the subjects actually were able to walk straight, and the results revealed that all walked in a sinuous line rather than a straight line. Periodicity and amplitude of the meandering differed from subject to subject. These facts suggest that none of us can walk in a strictly straight line; rather, we meander, primarily due to a slight structural or functional imbalance of our limbs, which produces a gait asymmetry, and secondarily due to feedback from our sense of sight, which acts to correct the shifted walking course.

Adult↗

PubMed2004

The evolution of dip-pen nanolithography.

The ability to tailor the chemical composition and structure of a surface on the 1-100 nm length scale is important to researchers studying topics ranging from electronic conduction, to catalysis, to biological recognition in nanoscale systems. Dip-pen nanolithography (DPN) is a new scanning-probe based direct-write tool for generating such surface-patterned chemical functionality on the sub-100 nm length-scale, and it is a technique that is accessible to any researcher who can use an atomic force microscope. This article introduces DPN and reviews the rapid growth of the field of DPN-related research over the past few years. Topics covered range from the development of new classes of DPN-compatible chemistry, to experimental and theoretical advances in the understanding of the processes controlling tip-substrate ink transport, to the implementation of micro-electro-mechanical system (MEMS) based strategies for parallel DPN applications.

Nanotechnology↗

PubMed1977

Pulmonary circulation--vertebral venous interconnections in the chickens.

Injections of India ink colored blood, latex, and plastic followed by study of corrosion casts and dissections were used to determine the interconnections of the vertebral venous system and pulmonary circulation in the chicken. Multiple, minute connections are found to the intercostal veins, small mesenteric veins and others connected to the vertebral venous system. Thus, blood can flow in quantities between the vertebral venous system and the pulmonary circulation depending upon pressure gradients.

Animals↗

PubMed1982

A reexamination of rat ductuli efferentes.

In 33 testes from a random selection of rats a 10% suspension of India ink in normal saline was introduced through the rete testis into the emergent ductuli efferentes. Low-power microscopy and microradiography confirmed the individually independent origin of each ductule. Five ductules were isolated in each of 17 testes, 4 ductules in 6, 6 ductules in 8, and in 2 testes, 7 and 9 ductules, respectively. In six animals minor variations existed as between the right and left testes +/- 1 in 4 and +/- 2 in 2. It is necessary to exercise great caution in the interpretation of results of experimental work on alteration of the ductuli, because of variability between colonies and within strains of rats.

Animals↗

PubMed1985

The presence of lymphatic stomata in the ovarian bursa of the golden hamster.

The histology and function of the lymphatic system in the ovarian bursa of the golden hamster were examined at each day of the estrous cycle. The lymphatic passage from the ovarian bursa to a para-aortic lymph node was stained black by india ink injected into the bursal cavity. This suggests that bursal fluid drains from the cavity via lymphatic vessels. Lymphatic stomata connecting the bursal cavity with the lymphatic lumen were consistently present throughout the cycle. However, the stomata were more frequently observed in the bursae on day 1 than on day 4 of the cycle. Also, they were more frequently observed in the bursa injected with 5 microliters of chick erythrocytes than in the contralateral (not injected) bursa in hamsters on day 4 of the cycle. These results suggest that the stomata are openings the patency of which varies in response to changes in the bursal cavity. There were regions where the lymphatic lumen was separated from the bursal cavity only by lymphatic endothelial cells. These regions were present throughout the estrous cycle. They may be patent stomata; dehiscence of junctions between the endothelial cells may give rise to stomata or widen the stomata orifices that are already present.

Animals↗

PubMed1989

Neural crest ablation does not alter pulmonary vein development in the chick embryo.

Cranial neural crest, which extends from the mid-diencephalon to somite five, plays an integral role in development of pharyngeal arch derivatives and supplies mesenchyme to the aortic arch arteries. Neural crest cells in pharyngeal arches three, four, and six migrate to the heart and are involved in aorticopulmonary and conotruncal septation. Ablation of the "cardiac" neural crest cells in chick embryos results in a variety of outflow tract anomalies, including persistent truncus arteriosus. Although other studies have shown the importance of the neural crest in the development of the cardiac outflow tract, the role of neural crest in venous development has not been established. This investigation evaluates the effect of cardiac neural crest ablation on the morphological development of the pulmonary vein. The presence of the pulmonary vein was confirmed initially at early stage 15 using histological sections and computer reconstructions of serially sectioned, normal embryos. India ink injections demonstrated a complete, patent pulmonary circuit at stage 18. Cardiac neural crest was ablated at stages 8-10. Operated, sham-operated, and control embryos were sacrificed at incubation day 11, and acrylic plastic casts prepared of the intravascular compartment. In experimental embryos with persistent truncus arteriosus, there were no morphological differences in the pulmonary veins, compared with shams and controls. These data indicate that the lesions of the cardiac neural crest have little morphological impact on pulmonary vein development. It is concluded that alterations in the cardiac neural crest are not involved in venous anomalies such as cor triatriatum and total or partial anomalous pulmonary venous return.

Animals↗

PubMed1991

Experimental analysis of blood vessel development in the avian wing bud.

Shortly after its appearance, the avian limb bud becomes populated by a rich plexus of vascular channels. Formation of this plexus occurs by angiogenesis, specifically the ingrowth of branches from the dorsal aorta or cardinal veins, and by differentiation of endogenous angioblasts within limb mesoderm. However, mesenchyme located immediately beneath the surface ectoderm of the limb is devoid of patent blood vessels. The objective of this research is to ascertain whether peripheral limb mesoderm lacks angioblasts at all stages or becomes avascular secondarily during limb development. Grafts of core or peripheral wing mesoderm, identified by the presence or absence of patent channels following systemic infusion with ink, were grafted from quail embryos at stages 16-26 into the head region of chick embryos at stages 9-10. Hosts were fixed 3-5 days later and sections treated with antibodies that recognize quail endothelial cells and their precursors. Labeled endothelial cells were found intercalated into normal craniofacial blood vessels both nearby and distant from the site of implantation following grafting of limb core mesoderm from any stage. Identical results were obtained following grafting of limb peripheral mesoderm at stages 16-21. However, peripheral mesoderm from donors older than stage 22 did not contain endothelial precursors. Thus at the onset of appendicular development angioblasts are present throughout the mesoderm of the limb bud. During the fourth day of incubation, these cells are lost from peripheral mesoderm, either through emigration or degeneration.

Animals↗

PubMed1993

Experimental study of the development of the truncus arteriosus of the chick embryo heart. I. Time of appearance.

The time of appearance of the truncus arteriosus was studied in the chick embryo using an in ovo labeling technique. Three hundred embryos at stages 13-18 of Hamburger and Hamilton were selectively labeled at the distal end of the heart tube, using gelatine-india ink label; 122 of these embryos were reincubated and 111 of them reached stages 25-28. In these stages the final location of the label was determined. Only 95 of these embryos showed both a normal heart and a label located in it. The remaining embryos were discarded due to abnormal cardiac morphology or because the label was not found. Embryos labeled at stages 13-14 had label in the conus in 42.8% of the cases and in the boundary between the conus and the truncus arteriosus in 57.1% of the cases. Label placed at stages 15-16 was located in the conus in 6.1% of the cases, in the boundary between the conus and the truncus arteriosus in 44.8% of the cases, and in the truncus arteriosus in 48.9% of the cases. Finally, label placed at stages 17-18 was located in the boundary between the conus and the truncus arteriosus in 18.7% of the cases and in the truncus arteriosus in 81.2% of the cases. Our results permit us to conclude that the truncus arteriosus appears in the chick embryo as early as stages 15-16 of Hamburger and Hamilton (50-56 hours of incubation).

Animals↗

PubMed2004

Effects of dehydroepiandrosterone on articular cartilage during the development of osteoarthritis.

OBJECTIVE: To investigate the in vivo effects of dehydroepiandrosterone (DHEA) on knee joints during the development of experimentally induced osteoarthritis (OA). METHODS: Twenty-two mature NZW rabbits underwent bilateral anterior cruciate ligament transection (ACLT) and received 0.3-ml intraarticular injections of DHEA (at a concentration of 100 microM in phosphate buffered saline) and control solution in the right and left knees, respectively, beginning 4 weeks after ACLT and continuing once weekly for 5 weeks. All animals were killed 9 weeks after surgery, and the knee joints were assessed by gross morphologic, histologic, histomorphometric, and biochemical methods. RESULTS: Gross morphologic inspection following India ink application showed that the right femoral condyles, which received DHEA, demonstrated less severe cartilage damage than did the contralateral condyles. The thickness, area, and roughness of the DHEA-treated femoral condyles provided evidence of a cartilage-protecting effect of DHEA following ACLT. These results were supported by gene expression analysis. Messenger RNA expression of a proinflammatory cytokine, interleukin-1beta, and catabolic enzymes, matrix metalloproteinases 1 and 3, was reduced in the cartilage of the DHEA-treated knee joints, and expression of tissue inhibitor of metalloproteinase 1 was increased. CONCLUSION: Results of the present study demonstrate a cartilage-protecting effect of DHEA during the development of OA following ACLT in a rabbit model.

Animals↗

PubMed1983

Effects of microwave exposure on the hamster immune system. II. Peritoneal macrophage function.

Acute exposure to hamsters to microwave energy (2.45 GHz; 25 mW/cm2 for 60 min) resulted in activation of peritoneal macrophages that were significantly more viricidal to vaccinia virus as compared to sham-exposed or normal (minimum-handling) controls. Macrophages from microwave-exposed hamsters became activated as early as 6 h after exposure and remained activated for up to 12 days. The activation of macrophages by microwave exposure paralleled the macrophage activation after vaccinia virus immunization. Activated macrophages from vaccinia-immunized hamsters did not differ in their viricidal activity when the hamsters were microwave- or sham-exposed. Exposure for 60 min at 15 mW/cm2 did not activate the macrophages while 40 mW/cm2 exposure was harmful to some hamsters. Average maximum core temperatures in the exposed (25 mW/cm2) and sham groups were 40.5 degrees C (+/- 0.35 SD) and 38.4 degrees C (+/- 0.5 SD), respectively. In vitro heating of macrophages to 40.5 degrees C was not as effective as in vivo microwave exposure in activating macrophages to the viricidal state. Macrophages from normal, sham-exposed, and microwave-exposed hamsters were not morphologically different, and they all phagocytosed India ink particles. Moreover, immune macrophage cytotoxicity for virus-infected or noninfected target cells was not suppressed in the microwave-irradiated group (25 mW/cm2, 1 h) as compared to sham-exposed controls, indicating that peritoneal macrophages were not functionally suppressed or injured by microwave hyperthermia.

Animals↗

PubMed2003

Vascularity and neuroreceptors of the pes anserinus: anatomic study.

The primary aim of this work was to evaluate the neurovascular network of the pes anserinus (PA) at its tibial insertion because the PA is often used for anterior cruciate ligament (ACL) reconstruction. Four fresh cadaver knees were injected with India ink gelatin solution and the arteries that supply blood to the PA were identified; microscopic studies of vessels and nerve fibers were also performed. Superficial and deep branches of the inferior medial genicular artery contribute to an arterial arch that courses deep to the PA insertion. A widespread array of small vessels and nerve fibers penetrate the PA insertion and course along the length of the gracilis and semitendinosus tendons. Computer analysis revealed that the mean diameter of the vessels decreased from 2201 microm at the insertion to 661 microm midway along the length of the tendon (mean tendon length = 17 cm; range = 13-21 cm); the cross-sectional area of the vessels per histologic section decreased from 336.37-137.05 microm(2). This study demonstrates that the PA insertion is well vascularized and richly innervated and that these morphological features continue along the length of the tendons.

Anterior Cruciate Ligament↗

PubMed2004

Arteriovenous glomeruli of the human spinal cord and their possible functional implications.

A previous investigation of the radiculomedullary vascular distribution of the human spinal cord showed an immediate filling of the peripheral spinal veins during arterial injections. Because the perfused medium, a mixture of latex and India ink, had a sufficient viscosity to preclude capillary passage, an extensive system of arteriovenous anastomoses (AVA) was indicated. The injection of five additional anatomic cadaver spinal cords was undertaken to specifically determine the intraparenchymal position and structure of these AVA. It was found that only cleared and transilluminated longitudinal parasagittal sections adequately showed that the AVA were formed by an extensive array of intricately coiled arteriovenous glomeruli (AVG) that could pass substantial amounts of blood from third order arterial branches to equivalently sized veins, bypassing the capillary bed. The epithelioid structure of these AVG channel walls, coupled with their highly innervated adventitial tissue indicated a possible functional relationship to similar structures found in the ends (digital pads) of mammalian extremities. Stained serial sections of injected cords showed the vascular relations with nerve fibers derived from the intraspinal parenchyma as well as a possible extraparenchymal autonomic fiber source. The numbers and extent of these AVG complexes suggested they might be involved in the remarkable autoregulation of spinal cord blood flow (SCBF) that is impervious to middle range changes in systemic blood pressure. Future research may more accurately determine the functional role of these previously unreported human spinal AVG, particularly in their possible relation to SCBF autoregulation in normal and injured spines.

Adult↗