Head Sinus Research Articles

Embryology of the Cavernous Sinus and Relevant Veins.

The cavernous sinus (CS) is a parasellar dural envelope containing an important venous pathway. The venous channels, which have an endothelial layer and no smooth muscle layer, are located in connective tissue. In the early embryonic stages, the neural tube is surrounded by the primitive capillary plexus and undifferentiated mesenchymal tissue, the primary meninx, and initially drains into the primary head sinus (PHS) through the anterior, middle, and posterior dural plexus (ADP, MDP, and PDP). Subsequently, following enlargement of the brain and differentiation of the mesenchyme, two major primary sinuses, the pro-otic sinus and the primitive tentorial sinus, become prominent. The pro-otic sinus is the remnant of the short segment of the PHS cranial to the MDP and the stem of the MDP. The CS originates from the plexiform channels medial to the trigeminal ganglion, namely the medial tributaries of the pro-otic sinus. The stem of the pia-arachnoidal vein draining into the ADP represents the primitive tentorial sinus. It is considerably elongated due to expansion of the cerebral hemisphere, and migrates medially toward the CS. The morphological changes in the CS and primitive tentorial sinus exhibit considerable variation in cerebral venous drainage patterns. Embryological knowledge facilitates interpretation of the anatomy of the CS, and it is useful to perform safe and beneficial endovascular treatment for the CS.

SPECIFIC MORPHOMETRIC FEATURES OF SUPERIOR SAGITTAL SINUS IN ADULTS

In order to determine the individual peculiarity of the shape, size, position and relations of the upper sagittal sinus, depending on the type of structure of the head in adults, craniometry and morphometry of the head sinuses were performed. The most significant venous collector of the brain is the upper sagittal sinus, which is located in the sagittal plane along the ridge of the lattice to the inner occipital projection. This formation is characterized by a triangular shape. The upper wall is formed by the leaves of the convex part of the solid membrane, and the two lateral walls by splitting the sickle of the cerebellum in the parasagittal plane. In adults, the upper wall contacts the inner surface of the parietal and occipital bones of the cranial vault. According to our data, the upper sagittal sinus has a specific range of variability depending on age, sex and head shape. The range of individual variability of the structure of the upper sagittal sinus was determined, which is characterized by the greatest values of length and height in adults, irrespective of gender with dolichomorphic head shape (narrow-headed) and increase in latitudinal parameters in people with meso- and brachymorphic head (middle and wide).

Anatomical map of the cranial vasculature and sensory ganglia.

There is growing evidence of a direct influence of vasculature on the development of neurons in the brain. The development of the cranial vasculature has been well described in zebrafish but its anatomical relationship with the adjacent developing sensory ganglia has not been addressed. Here, by 3D imaging of fluorescently labelled blood vessels and sensory ganglia, we describe for the first time the spatial organization of the cranial vasculature in relation to the cranial ganglia during zebrafish development. We show that from 24h post-fertilization (hpf) onwards, the statoacoustic ganglion (SAG) develops in direct contact with two main blood vessels, the primordial hindbrain channel and the lateral dorsal aortae (LDA). At 48hpf, the LDA is displaced medially, losing direct contact with the SAG. The relationship of the other cranial ganglia with the vasculature is evident for the medial lateral line ganglion and for the vagal ganglia that grow along the primary head sinus (PHS). We also observed that the innervation of the anterior macula runs over the PHS vessel. Our spatiotemporal anatomical map of the cranial ganglia and the head vasculature indicates physical interactions between both systems and suggests a possible functional interaction during development.

Embryonic Primary Head Sinus may Persist in the Petrosal Bone

Embryonic Primary Head Sinus may Persist in the Petrosal Bone

Sox7 controls arterial specification in conjunction with hey2 and efnb2 function.

SoxF family members have been linked to arterio-venous specification events and human pathological conditions, but in contrast to Sox17 and Sox18, a detailed in vivo analysis of a Sox7 mutant model is still lacking. In this study we generated zebrafish sox7 mutants to understand the role of Sox7 during vascular development. By in vivo imaging of transgenic zebrafish lines we show that sox7 mutants display a short circulatory loop around the heart as a result of aberrant connections between the lateral dorsal aorta (LDA) and either the venous primary head sinus (PHS) or the common cardinal vein (CCV). In situ hybridization and live observations in flt4:mCitrine transgenic embryos revealed increased expression levels of flt4 in arterial endothelial cells at the exact location of the aberrant vascular connections in sox7 mutants. An identical circulatory short loop could also be observed in newly generated mutants for hey2 and efnb2. By genetically modulating levels of sox7, hey2 and efnb2 we demonstrate a genetic interaction of sox7 with hey2 and efnb2. The specific spatially confined effect of loss of Sox7 function can be rescued by overexpressing the Notch intracellular domain (NICD) in arterial cells of sox7 mutants, placing Sox7 upstream of Notch in this aspect of arterial development. Hence, sox7 levels are crucial in arterial specification in conjunction with hey2 and efnb2 function, with mutants in all three genes displaying shunt formation and an arterial block.

Head sinuses, melon, and jaws of bottlenose dolphins, Tursiops truncatus, observed with computed tomography structural and single photon emission computed tomography functional imaging

The head sinuses, melon, and lower jaws of dolphins have been studied extensively with various methods including radiography, chemical analysis, and imaging of dead specimens. Here we report the first structural and functional imaging of live dolphins. Two animals were imaged, one male and one female. Computed tomography (CT) revealed extensive air cavities posterior and medial to the ear as well as between the ear and sound-producing nasal structures. Single photon emission computed tomography (SPECT) employing 50 mCi of the intravenously injected ligand technetium [Tc-99m] biscisate (Neurolite) revealed extensive and uptake in the core of the melon as well as near the pan bone area of the lower jaw. Count density on SPECT images was four times greater in melon as in the surrounding tissue and blubber layer suggesting that the melon is an active rather than a passive tissue. Since the dolphin temporal bone is not attached to the skull except by fibrous suspensions, the air cavities medial and posterior to the ear as well as the abutment of the temporal bone, to the acoustic fat bodies of each lower jaw, should be considered in modeling the mechanism of sound transmission from the environment to the dolphin ear.

An analysis of bone and head sinus cancers in radium dialpainters using a two-mutation carcinogenesis model

Bone and head sinus cancer incidence after ingestion of226Ra and 228Ra by radium dial painters isanalysed using a two-mutation clonal expansion model forradiation carcinogenesis, taking into account the retention andradiation patterns of these nuclides in the body. The best fit isobtained for compact bone retention and efficient diffusion of222Rn to the bone cavities and radiation action on bothmutation rates of the cancer model, as found in a similar analysisof bone sarcomas after 226Ra injection in beagles. Themodel parameters of the best fit are consistent with cellularradiobiological data and a previous analysis of lung cancer inuranium miners. Due to the low background incidence of bone andhead sinus cancer, the resulting dose-effect relationships forthese cancers are linear-quadratic with radium ingestion and alpharadiation dose. These results do not support a threshold doseconcept, but the risks at low doses calculated by the model comeout to about a factor 10 lower than using a linear extrapolation ofthe data to low doses, a procedure currently applied by ICRP andEPA. Furthermore, the model results indicate radiation risks atlow doses to be related with background cancer incidencebetween relative and absolute radiation risk projections. Theresults, which are dependent on the model assumptions, might bemore generally applicable for bone seekers and will thereforeneed further study to arrive at better radiation risk estimations.

The stimulating effect of the Dorsal-Body Hormone on cell differentiation in the female accessory sex organs of the hermaphrodite freshwater snail, Lymnaea stagnalis

An experimental study has been made on the role of the Dorsal Body Hormone (DBH) of the Dorsal Bodies (DB), of the growth hormone of the neurosecretory Light Green Cells (LGC) of the cerebral ganglia, and of the differentiation of the various secretory cell types in the accessory sex organs (ASO) of the hermaphrodite freshwater pulmonate snail L. stagnalis. To study this problem, undifferentiated rudiments of the ASO of juvenile snails were transplanted into the haemocoel of the head sinus of adult acceptors subjected to various types of operations. After 6 weeks the male and female ASO of sham-operated control acceptor snails showed clear signs of differentiation. The female ASO, with the exception of the ciliated groove, of DB or of DB + LGC cauterized acceptors had not differentiated. Reimplantation of DB or of DB + LGC stimulated the normal differentiation process. It is concluded that the cellular differentiation of the female ASO is controlled by the DBH. This hormone has no effect on the differentiation of the male ASO. The growth hormone of the LGC has no effect on the differentiation of either the female or the male ASO. Whether the differentiation of the male ASO is controlled by other endocrine centers remains to be studied.

Progress in the beagle studies at the University of Utah.

Abstract Young adult beagles are given single intravenous injections of monomeric 252Cf, 249Cf, 241Am, 239Pu, 228Th, 226Ra, 228Ra or 90Sr in citrate solution to achieve reproducible deposition patterns in tissue. Injected transuranium atoms become attached to transferrin and other substances in blood plasma. The skeleton and liver are the primary sites of deposition, although high local concentrations of californium, berkelium and americium also occur in the thyroid and kidney, and radium also concentrates in the eye. The initial skeletal deposition of monomeric transuranium elements is on bone surfaces. The mean local dose-rate to the soft-tissue layer 0–10 mi from the mineralized bone surfaces of the beagle is about 20 times higher when 239Pu is on bone surfaces than for an equal amount of 239Pu randomly distributed throughout the bone mineral. Thus, the rate of bone-surface remodeling has a very important influence on the skeletal toxicity of the transuranium elements. The initial liver deposition of monomeric transuranium elements is rather uniform and mainly in the hepatic cells. Subsequently, much of the radioactivity shifts into the liver reticulo-endothelial cells that line the sinusoids. At long times after injection, the distribution is very non-uniform, being highest in the portal region and lowest in the regenerative nodules. All, or virtually all, of the life-shortening from medium and low doses has been due to radiation-induced cancer. Bone sarcomas have been the most frequent form of malignancy, but head sinus carcinomas, liver tumors, and eye melanomas have also been induced. On the basis of average skeletal dose, 1 rad from 239Pu is the equivalent of 5–10 rads from 226Ra in the induction of bone sarcomas. This is because in the skeleton a considerable fraction of the 239Pu disintegrations occur on bone surfaces near cells, whereas most of the skeletal disintegrations from 226Ra take place within bone mineral. Plutonium will continue to be our chief interest, not only at low doses, but perhaps at different ages and in different chemical forms. We will continue to study other radionuclides of practical and fundamental importance. Ours is the first experiment in which tumor induction by fission fragments (252Cf) is being determined.

CONVULSIVE STATES WITH EVIDENCE OF BRAIN HEMIATROPHY

1. Attention is called to a roentgenographic syndrome of hemilateral cerebral hypoplasia and atrophy with concomitant increase of thickness of the skull and enlargement of the head sinuses which occurs in certain convulsive states. 2. Nine cases are described which presented this syndrome. The etiological factors were traumatic, inflammatory or vascular. 3. The nature of the pathological process is discussed from the point of view of brain growth.