bluuebunny/crossref_metadata_2025 huggingface dataset:
Scanning Electron Microscopic and Histochemical Studies of Foliate Papillae in the Rabbit, Rat and Mouse
Authors: Liu H.C. , Lee J.C.
Published: July 2008

The foliate papillae of the rabbit, rat and mouse were studied by scanning electron microscopy and histochemistry. The papillae consisted of folds and grooves located on the posterolateral margin of the tongue in front of the circumvallate papillae. The numbers of folds and taste buds varied among the three animal species. Scanning electron microscopy showed that in longitudinal sections the taste buds were oval in shape and their pores were surrounded by microvilli. The reaction product of alkaline phosphatase could only be demonstrated in the superficial epithelium of the rabbit as well as in the mouse foliate papillae, but it also diffused into the taste buds in the rat. The intensity and distribution of the reactions of adenosine triphosphatase, acetylcholinesterase and butyrylcholin-esterase were identical to those reported by other investigators in spite of differences in animal species and histochemical techniques employed.
Anatomical Features of the Liver in Situs Inversus
Authors: Ion Albu , Tiberiu Ciobanu G.
Published: July 2008

The hepatic veins and the intrahepatic branches of both the portal vein and the hepatic artery have been dissected and studied in three specimens of liver obtained from bodies with situs inversus. The position of the hepatic veins was found generally to correspond to the intersegmental scissure planes of the liver. The intrahepatic branches of the portal vein were found to deliniate the subdivision of the liver into lobes, segments and subsegments which correspond to the ‘mirror image’ of the normal liver. The arterial irrigation derives from the mirror image constituting peculiar patterns in each of the specimens. In the first specimen, the left hepatic artery irrigates the superior subsegments of the right lobe, which depends on the right branch of the portal vein. In the second specimen, a voluminous anastomotic intrahepatic channel was noted between the right hepatic artery and the subsegmental posterior inferior branch of the left hepatic artery. In the third specimen, the arterial branch which irrigated the inferior subsegments of the right lobe also contributed to the irrigation of the superior lateral subsegment.
A New Look at the Blood Supply of the Ileocolic Angle
Authors: Vandamme J.P.J. , Bonte J.
Published: July 2008

87 ileocolic preparations are studied by means of postmortem arteriography combined with dissection and corrosion. The ileocolic stem is to be continued beyond the colic and ileal branches up to its division into the caecal branches. This allows to distinguish a long ileocolic trunk which is the direct origin of the different tributaries and which ends into one or both caecal arteries. An arteria colica dextra from the ileocolic artery cannot be supported. Many rules are established that govern the relations between the various collaterals, and several conclusions of theoretical and practical importance are made.
Collagen Arrangement in Cartilages
Authors: Zambrano N.Z. , Montes G.S. , Shigihara K.M. , Sanchez E.M. , Junqueira L.C.U.
Published: July 2008

The collagen arrangement of different cartilages of several mammals was studied by the Picrosirius-polarization method applied to tissue sections whose proteoglycans had been previously removed by enzymatic digestion. This procedure not only increases collagen birefringency but it also enhances the optical resolution, permitting an accurate observation of the collagen disposition in this tissue. Our observations led to the conclusion that in the material studied at least five general patterns of collagen arrangement occur. When studied with the aid of electron microscopy, different cartilages showed variable values in their collagen fibril diameter. The results obtained suggest a greater variability in the collagen fibril diameters of those cartilages submitted to strong pressures.
Transplantation of the Interfrontal Suture in the Wistar Rat
Authors: Oudhof H.A.J. , Markens I.S.
Published: July 2008

By excising a 3-day-old interfrontal suture with adnexa and transplanting it into the sagittal suture of a 10-week-old rat of the same inbred strain, the development of the interfrontal suture under experimental conditions could be studied. The effect was a distinct delay of the moment of closure of the suture, namely, from normal period of 1 week to that of 4 or 5 weeks. It was found that after an initial osteosynthesis, the interfrontal suture reopened and then became part of the system of open sutures in the cranial vault of the donor rat.
Quantitative Ultrastructural Studies of the Cat Carotid Body
Authors: Ballard T. , Blakeman N. , Pallot D.J. , Al-Neamy K.A.W.
Published: July 2008

The results of a stereological analysis of cat carotid body tissue are described. Type I cells account for some 10% of organ volume, vessels for 24% and nerve endings some 0.5%. Very nearly 50% of the total organ volume is composed of non-specific tissue.
Transplantation of Free Perichondrial Grafts into Rabbit Articular Cartilage is Associated with Matrix Vesicle Calcification
Authors: Bab I. , Sela J. , Stein H.
Published: July 2008

Autogenous perichondrial grafts from rabbit ear were transplanted into articular cartilage defects in the knee joint. Electron micrographs performed after 2 months revealed calcifications associated with cartilaginous-forming cells and extracellular matrix vesicles. Many of these vesicles contained apatite crystals, particularly in areas adjacent to the calcifying fronts. In these areas the vesicular membrane was occasionally ruptured by the crystals. Many crystals in the calcifying front proper were organized alongside collagen fibers. Examination of sham-operated and normal controls revealed the occurrence of non-calcifying matrix vesicles. The results of the present and previous studies suggest that matrix vesicles occur in normal articular cartilage in a latent form, their calcification being associated with changes of the metabolic state of the tissue.
Juxtanuclear Globule of the Human Fimbrial Epithelium Ciliary Cell: A Histo- and Cytochemical Study
Authors: Peretz B.A. , Lindenbaum E.S. , Beach D.
Published: July 2008

Microbiopsies of human Fallopian tube fimbrial epithelium were obtained during routine gynecological operations, and during pregnancy while undergoing hysterectomy in the first trimester or cesarean section in the third trimester. Specimens were studied under light and electron microscopes utilizing histo- and cytochemical techniques. Large juxtanuclear globules were demonstrated in the ciliary cell at all stages of the cycle. During the proliferative phase, these globules contained large lipid droplets and glycogen rosettes. The content of the globules in the early luteal phase was mostly amorphous electron-lucid material which failed to stain with PAS, alcian blue and the Millon reaction. However, reaction products of acid phosphatase as well as calcium precipitate were scattered in them as discrete granules. The same type of globule was found in early pregnancy. During late luteal phase and late pregnancy, the content of the globule was once again composed of lipids and glycogen. It seems that lipid and glycogen accumulate during the preovulatory phase, while depletion and dispersion of these substances occur in the periovulatory phase, probably due to increased energy utilization. Late luteal phase revealed subsequent replenishment of these reserves, as was also revealed in late pregnancy.
The Development of the Lobes of the Metanephros and Fetal Kidney
Authors: Fine H.
Published: July 2008

Observations with a dissecting microscope revealed a regular pattern of lobar development, from the centre outwards, for particular stages of development of the kidney in the embryo and fetus. A growth area near the poles is suggested, and further study is indicated to relate this to histogenesis. A formula is devised to facilitate the study of the lobation.
The Cerebellar Arteries: Cortical Patterns and Vascularization of the Cerebellar Nuclei
Authors: Icardo J.M. , Ojeda J.L. , Garcia-Porrero J.A. , Hurle J.M.
Published: July 2008

This paper reports an anatomical study of the vascular supply in 60 human cerebelli from subjects of both sexes, aged between 20 and 60 years, who had died of various accidental causes. The origin, branching pattern and cortical and central distributions of the cerebellar arteries have been studied by gross dissection, vascular injection and corrosion procedures. Variations of the normal pattern of the cerebellar arteries in both origin and cortical distribution are frequently found, the anterior inferior and the posterior inferior cerebellar arteries being the arteries showing the highest number of variations. The anomalies most frequently found are duplication in the origin, abnormal origin, and the presence of hypoplastic vessels. The cerebellar nuclei were supplied by the rhomboidal artery, a collateral branch of the superior cerebellar artery. The formation of a precise segmentary vascular pattern into the dentate nucleus by branches arising from the rhomboidal artery is described. The results are discussed in the light of other anatomical studies.
Fine Structure of the Retinal Epithelium, Bruch’s Membrane (Complexus Basalis) and Choriocapillaris in the Domestic Ferret
Authors: Braekevelt C.R.
Published: July 2008

The fine structure of the retinal epithelium, choriocapillaris, and Bruch’s membrane has been studied by electron microscopy in the domestic ferret. The ferret possesses a tapetum cellulosum in the superior fundus, and the morphology of the retinal epithelium and its associated structures varies depending upon its relation to the tapetum. Over the tapetum the retinal epithelium is a single layer of low cuboidal cells with basal infoldings and two types of apical process. Internally the cells are non-pigmented, display much smooth endoplasmic reticulum, little rough endoplasmic reticulum, lysosomes, phagosomes, and a basally located nucleus. The choriocapillaris is composed of large capillaries indented into the retinal epithelium. Bruch’s membrane is thin and composed of three layers. In non-tapetal regions the retinal epithelial cells are pigmented but display most of the other features noted over the tapetum. The choriocapillaris is not indented in non-tapetal areas. Bruch’s membrane appears identical to that noted over the tapetum. Wandering phagocytes are occasionally noted at the retinal epithelium-photoreceptor junction.
Histoenzymological Comparison of the Prostate Gland of Sexually ‘Quiescent’ and ‘Active’ Taphozous Melanopogon Temmnick (Microchiroptera: Mammalia)
Authors: Swami D.R. , Lall S.B.
Published: July 2008

Lysosomal hydrolases (e.g., acid phosphatase, AcPase; adenosine triphosphatase, ATPase, and lipase) and the mitochondrial ‘marker’ enzyme succinic dehydrogenase (SDH) were evaluated histochemically in the prostate gland of sexually ‘quiescent’ and ‘active’ bats. During the former state, AcPase activity was significantly less than in sexually active animals, suggesting that prostate AcPase activity is androgen dependent. Levels of lipase activity also were highest in the prostate of sexually active bats, suggesting the importance of endogenous lipids which may be mobilized and used as a source of energy. SDH and ATPase sites and patterns of distribution in the prostate gland of bats were closely similar during the two reproductive states. Differential enzymological patterns do not seem to have any significant correlation with the morphological changes which occur in the glandular epithelium, musculature, urethra and the luminal fluid, as the animals pass from a ‘quiescent’ phase to one of activity and vice versa as observed in the present study.
Quantitative Ultrastructural Studies of the Cat Carotid Body
Authors: Pallot D.J. , Blakeman N.
Published: July 2008

The results of a stereological analysis of cat carotid body type I cells are described. General ultrastructure is described as well as quantitative analysis of the cell organelles. Four types of nerve endings are identified on the basis of their synaptic membrane specialisations. 92.99% symmetrical (unclassifiable), 4.9% pre-synaptic, 1.5% post-synaptic, 0.6% reciprocal. The species difference in comparison to the rat is noted and locations of afferent and efferent terminations are discussed.
Morphological Observations on the Papillae of the Opossum Tongue
Authors: Krause W.J. , Cutts J.H.
Published: July 2008

The dorsum of the opossum tongue shows filiform, fungiform, conical and three vallate papillae. An additional type, the compound filiform papilla, is characteristic of most marsupials, including the opossum. These are unique structures in which the epithelium forms fringe-like, keratinized projections around the apical borders of the papillae. The covering epithelium is an extensively keratinized, stratified squamous type with a well-developed stratum granulosum containing numerous keratohyalin granules. Large, heavily cornified conical papillae occur in a patch near the anterior end of the tongue and the apex of each papilla is directed posteriorly. Taste buds are associated with only the three vallate papillae which form a triangle near the base of the tongue. They are not present on the fungiform papillae or in the posterolateral mucosal folds which appear to replace the foliate papillae of other species.Introduction
Intimal Folds of the Rabbit Aorta
Authors: Tindall A.R. , Svendsen E.
Published: July 2008

This work describes the use of an impression compound Silgel 604 to obtain casts of the intimal surface of the rabbit aorta distended to either systolic or diastolic in vivo diameter. Other rabbit aortas were fixed by glutaraldehyde at in vivo distensions. Specimens from these aortas were examined by scanning electron microscopy. Longitudinal folds were found in all cases at both diastolic and systolic distensions. The possible functions of the folds are discussed.
Sarcomere Length and EMG Activity in Some Jaw Muscles of the Rabbit
Authors: Weijs W.A. , van der Wielen-Drent T.K.
Published: July 2008

The sarcomere length of the rabbit pterygoid, temporal and digastric muscles was determined in seven mandibular positions. Six positions are representative of mastication, one of gnawing. Jaw displacement has a different effect in jaw openers (digastric and lateral pterygoid) and closers. The sarcomeres of the openers are long when the jaw is in molar occlusion and shorten relatively little at jaw opening. In the jaw closers they are very short in molar occlusion and become strongly extended when the mouth is open. Timing of electrical activity and sarcomere shortening corresponds closely. All muscles become active at sarcomere lengths of 2.6–3.1 µm. In the jaw closers, sarcomeres shorten till 2.1–2.3 µm during activity; in the jaw openers they do not shorten beyond 2.6–2.7 µm. Hence the openers remain close to optimum length (2.7 µm) while the closers shorten to lengths where possibly only 60% of the maximal isometric force can be exerted. During the initial phase of jaw closing, the medial pterygoid and temporalis shorten at speeds estimated to approach 50% of the presumed maximum speed. During the rest of the closing and power stroke, contraction takes place under near-isometric conditions, with little loss of force due to shortening. The jaw openers act at low shortening velocities.
Presence of Chondroid Tissue in the Symphyseal Region of the Growing Human Mandible
Authors: Goret-Nicaise M. , Dhem A.
Published: July 2008

The mandibular symphysis studied by histology and microradiography in the fetus and in the newborn shows a mineralized tissue different from the calcified cartilage observed in endochondral ossification and also different from bone aspects. In 1888, Schaffer coined it ‘chondroid bone’, but this tissue derives from secondary cartilage. We therefore suggest the term ‘chondroid tissue’ to designate it.
Trophic Specificity of the Gustatory Fibers upon Taste Bud Regeneration
Authors: State F.A. , Hamed M.S. , El-Hashash M.K. , Gaber O.M.
Published: July 2008

24.adult dogs were classified into six groups; in 2 animals of each group the lingual nerve was transected distal to the point of entry of the chorda tympani and its proximal end was sutured to the distal end of the glossopharyngeal nerve. In the other 2 animals transtympanic chorda tympani neurectomy was performed before suturing the lingual and glossopharyngeal nerves. Invasion of the papillae by regenerating fibers from the 8th postoperative week onwards was followed by reappearance of taste buds only in lingual-glossopharyngeal anastomosis with intact chorda tympani. The difference in number of taste buds, size and number of constituent cells between the two operative procedures was statistically significant from the 8th week onwards. The significance of these findings was discussed.
Age-Related Changes in Prolactin Cell Percentage and Serum Prolactin Levels in Intact and Neonatally Gonadectomized Male and Female Rats
Authors: Takahashi Sumio , Kawashima Seiichiro
Published: July 2008

Electron microscopically the percentages of various pituitary cell types were calculated at 30 and 90 days of age. Prolactin cell percentage was more at 90 days of age than at 30 days in both intact male and female rats. No sexual difference was observed in the percentage of prolactin cells at 30 days of age, but at 90 days female pituitaries contained more numerous prolactin cells than male ones. Neonatal ovariectomy did not affect the prolactin cell percentage at 30 days of age, while it lowered the percentage at 90 days. Neonatal orchidectomy did not affect the prolactin cell percentage at both 30 and 90 days of age. Mitotic prolactin cells were more frequently observed in intact female rats at estrus than in intact male rats at 90 days of age. These results show the presence of the sexual difference in the proliferation of prolactin cells. Serum prolactin levels increased with age in intact male and female rats. In neonatall·y gonadectomized male and female rats the serum prolactin levels failed to increase at 60 and 90 days of age. In general conclusion, the changes in serum prolactin levels are in line with the changes in prolactin cell population during postnatal development.
Experiments and Ultrastructural Investigations on the Mouse Embryo during Early Teratogen-Sensitive Stages
Authors: Kuchta Brigitte
Published: July 2008

The effect of iron gluconate on the mouse embryo was studied in early embryonic development before the chorioallantoic placenta was established. Iron gluconate is teratogenic to mouse embryos after intraperitoneal application to pregnant mice on the 8th and 9th days of gestation. The most pronounced defect is exencephaly. As seen with the electron microscope, iron gluconate enters the cells of the yolk sac. The excessive uptake of iron gluconate in the cells of the yolk sac alters these cells for a short period. Iron gluconate is visible, neither in the cells of the head process nor in the cells of the neuroectoderm, but the neuroectodermal cells show necrotic degeneration. Two different types of necrosis can be found; these appear at a time (13–22 h after maternal treatment) when the yolk sac cells are normalized again.
Zur Entwicklung der kaudalen Abschnitte der Müllerschen Gänge bei der Ratte (Rattus norvegicus)
Authors: Del Vecchio Franziska R.
Published: July 2008

The development of the caudal portion of the Müllerian ducts was studied in rats. The following results were obtained: (1) In the female embryonic rat the proximal thirds of the caudal parts of the Müllerian ducts meet to form the anlage of the biluminal cervix uteri of the uterus duplex. The middle and the distal thirds of the Müllerian ducts fuse and become the canalis vaginalis.(2) In the female embryonic rat the canalis vaginalis represents the anlage of the cranial part of the vagina.(3) During embryonic life the epithelium of the sinus urogenitalis proliferates and develops into the vaginal plate.(4) At birth the vagina is closed by the vaginal plate.9%0 In the male embryonic rat the caudal parts of the Müllerian ducts degenerate completely in their proximal and middle thirds. The distal third (canalis vaginalis) disintegrates cranially, caudally it gives rise to the prostatic vaginula.(6) In the male rat the prostatic vaginula is a remnant of the vaginal anlage, unlike the prostatic utriculus in man which contains a remnant of the uterine anlage.
Anterograde and Retrograde Degenerative Reactions in Caudate Nucleus and Putamen after Experimental Lesion of the Pallidum in Squirrel Monkey (Saimiri sciureus)
Authors: Chung Y.W. , Hassler R.
Published: July 2008

After stereotactic lesions in the pallidum in 4 squirrel monkeys, electron microscopic material from the striatum was examined for anterograde and retrograde degenerative changes. In the experiment with pallidum internum lesion, only degenerated striatal fibers were observed, more than likely thalamostriatal fibers that pass through the site of the lesion. The three experiments with pallidum externum lesion revealed that the two types of striatal aspiny neurons react with a penumbral degeneration to interruption of their axons. Also, the axospinous type IV striatal synapses, which originate in the center median or parafascicular nucleus of the thalamus, react to interruption of their axons in the pallidum externum with the dark or crystalloid forms of degeneration. The plump axospinous type III synapses, which have previously not been differentiated, were the most frequently altered, showing dark, crystalloid, or pale forms of degeneration. Their degeneration can be attributed directly to the lesions of the pallidum externum nerve cells; thus, an immediate connection between the pallidum externum and the striatum has been demonstrated. A comparison of the retrograde degeneration of striated nerve cells after pallidum externum lesions with that following columnar isolation of striatal tissue revealed two overlapping forms of penumbral degeneration of the aspiny neurons.
Proliferation and Transformation of Lymphocytes in the Lung Capillaries of the Rat: Ultrastructure, Acid Phosphatase and Peroxidase Cytochemistry
Authors: Scheuermann Dietrich W.
Published: July 2008

After fixation by vascular perfusion numerous leukocytes, among which 91% lymphocytes – not only small but particularly medium- and large-sized categories – were observed in the lung capillaries of healthy Wistar rats. We are struck by the presence of lymphocytes belonging to different intermediate stages between small lymphocytes and plasma cells. Lymphocyte mitosis can be found in the lung capillaries, resembling ‘blast cell mitosis’. The different kinds of lymphocytes can be observed with a variable amount of uranylophilic membrane-bound granules with a diameter ranging from 200 to 400 nm. Acid phosphatase (AP) and peroxidase (PO) reaction product was found in several granules. The distribution of azurophil granules corresponds to that of the AP and PO positive granules. Since staining with uranyl acetate increases the density of the azurophil granules and thereby allows a direct electron microscopical identification of azurophils, AP reaction product was analyzed by X-ray microanalysis on the granules. Our findings indicate that azurophil granules in lymphocytes correspond to a form of lysosome containing AP and PO. Thus, it would appear that movement of blood cells to the lung capillaries is not random but preferentially favors cells of the lymphocytic series. The morphology and cytochemical reactions for AP and PO of the medium- and large-sized lymphocytes is characteristic of cells subjected to antigenic stimulation.
Zur Entwicklung der Bursa omentalis
Authors: Brummer G.
Published: July 2008

The development of the omental bursa (lesser sac) was studied in serial sections of hybrid mouse embryos of 9–11½ days. The anlage of the bursa is represented by several indentations on the right side of the mesenterium. Further growth and topographic alterations of the adjoining organs determine the definitive shape of the lesser sac. On the left side, the recessus pneumato-entericus is a transient structure which persists only until the 11th day of gestation. In humans, the anlage of the bursa is almost identical with its origin in mice. The bursa facilitates the separation from the digestive tract of several organs developing in the mesentery.
Development of the Articular Cavity in Paralyzed Chick Embryos and in Chick Embryo Limb Buds Cultured on Chorioallantoic Membranes
Authors: Mitrovic D.
Published: July 2008

The development of digital joints of chick embryo paralyzed with dacamethonium bromide and of joints in chick embryo limb buds cultured on chorioallantoic membranes was studied. The digital joints of 45 paralyzed and 40 control embryos and the joints of 37 grafts and 30 control legs were examined histologically. Six preselected grafts were studied by electron microscope. Our results demonstrate that paralysis does not completely inhibit the early stages of joint clefting. In many paralyzed embryos, small clefts appeared in the periphery and occasionally in the central part of the interzone. Unlike in normal embryos, they rapidly disappeared, inducing fusions across the joints. Early, 2-day paralysis during a period of normal clefting inhibited irreversibly the development of the articular cavity that failed to appear after a cessation of the drug. Paralysis initiated in older embryos caused rapid regression and partial fibrous ankylosis of previously fully differentiated joints. Grafts from 4- to 6-day-old embryos usually failed to develop a full range of skeletal segments. Normal development of skeletal segments occurred in grafts from older donors. The articular cavity failed to develop in almost all grafts. Early cavitation accompanied by characteristic cell changes was found in a few joints. These cellular changes are suggestive of an intrisic mechanism of early cavitation, but joint motion is required for the full differentiation and maintenance of the joint cavity.
Histomorphologic Studies of the Nasal Cavity of Sheep (Ovis aries) and Its Significance in Temperature Regulation of the Brain
Authors: Khamas W.A.H. , Ghoshal N.G.
Published: July 2008

10 sheep were used for light microscopic studies to describe the distributions of the blood vessels, epithelium, and glands of the nasal cavity. The animals were killed following intramuscular injection of Rompun solution (xylazine hydrochloride). The heads were sawed and tissues were taken from the alar fold, respiratory, and olfactory regions. More vascularity was noticed in areas of the nasal cavity that were in direct contact with the airstream. Moreover, in the submucosa, the presence of arteriovenous anastomoses, collagen fibers, elastic fibers, thick-walled or cushion veins, and free smooth muscle cells was observed, gradually decreasing from the rostral to caudal regions. The tunica media of the arteries was very thin in the vestibular region and relatively thicker in the respiratory region. On the other hand, luminal diameters of the arteries were very small in the respiratory region and relatively larger in the vestibular region. In addition, a large number of intra-arterial bolsters was present in the respiratory region, but there were fewer in the olfactory region, and they occurred with still less frequency in the vestibular region.
Cellular Composition of Human Fetal Bone Marrow
Authors: Carbonell F. , Calvo W. , Fliedner T.M.
Published: July 2008

The cellular composition of the human marrow was studied in thin sections of undecalcified bones of 24 fetuses aged from 11 to 22 weeks of gestation, embedded in methacrylate and stained by the Giemsa method. This procedure provides much better cellular detail than the decalcified bone sections embedded in paraffin used in previous studies. Hemopoiesis is already present at the 11th week of gestation in the long bones of the extremities. The cellularity of their marrow increases during the 4th month and is abundant in the months thereafter. Its composition is similar to that of adults but differs by the presence of a large number of stromal cells and by the absence of plasma cells and lymph follicles in the fetal marrow. Differential counts for blood-forming cells and stromal elements are given for the initial period of marrow development.
The Tracheo-Esophageal Septum – Fact or Fantasy?
Authors: Zaw-Tun H.A.
Published: July 2008

The so-called tracheo-esophageal septum is in fact the curved primitive floor that results from the ventrocaudal out-growth of the respiratory primordium from the caudal end of the laryngeal sulcus of the foregut. This floor, which separates the openings of the respiratory diverticulum and esophagus, is apparent in transverse sections as a bridge of tissue separating the lumina. The respiratory and hepatic primordia are contiguous initially, but they are separated very early by the rapid growth of the heart and liver, and the resultant stretching of the slower-growing foregut. The portion of foregut between the primordia is drawn out into a narrowing tube that develops into the esophagus and stomach. The respiratory primordium is drawn cranialward; it proliferates, dilates, bifurcates, and grows caudally, dragging out a stalk from the ventral aspect of the foregut. Most of the stalk above the bifurcation will develop into the trachea.
Intercellular Junctions between Smooth Muscle Cells in Myointimal Hyperplasia
Authors: Cuevas P. , Gutierrez Diaz J.A. , Reimers D.
Published: July 2008

Experimental intimal hyperplasia was obtained by microvascular surgery. A segment of the left common carotid artery of rat was grafted by means of end-to-end anastomosis onto the right common carotid artery of the same animal. 3 months after surgery, hyperplasia was observed in the intima of the grafted arterial segment formed by modified smooth muscle cells: myointimal cells. These cells do not present ultrastructural changes and they are connected by gap and tight junctions. The gap junctions are the predominant type of junction between myointimal cells in our experimental model.
A Note on the Duodenum of the West Indian Manatee (Trichechus manatus), with Emphasis on the Duodenal Glands
Authors: Reynolds, III J.E. , Krause W.J.
Published: July 2008

The anatomy of the duodenum of the West Indian manatee has both macroscopic and microscopic features that are unusual when compared to other mammalian forms. Macroscopically, the voluminous duodenal ampulla and the paired duodenal diverticula are distinctive. The general microscopic structure of the manatee duodenum is not unusual, but the duodenal glands secrete an acid mucin (sialomucin). The cells of these glands appear to be intermediate between classical serous and mucous cell types. These cells also contain granules with regions of high peripheral electron density. The overall structure of tlie manatee duodenum most strongly resembles that of the dugong, another member of the order Sirenia.
Response of Pericytes to Thermal Lesion in the Inguinal Fat Pad of 10-Day-Old Rats
Authors: Richardson R.L. , Hausman G.J. , Campion D.R.
Published: July 2008

The response of capillary pericytes to thermal lesion in the inguinal fat pad of 10-day-old rats was observed with the light and electron microscope. Samples were taken from the necrotic area and the immediately surrounding tissue at various time intervals from 1 h to 10 days post-lesion. The initial physical disruption and swelling of the capillary resulted in the liberation of some pericytes near the necrotic zone. Most pericytes remained, however, in the basal lamina and went through a period of activation that peaked at 48 h. Pericyte activation consisted of a noticeable increase in rough endoplasmic reticulum with the cisternae containing granular, electron-opaque material. There was evidence of migration of these activated cells from the capillary basal lamina between 24 and 72 h. By 72 h, fibroblast-like cells possessing different nuclear and cytoplasmic morphology were oriented along distinct bands of extracellular fibrin and necrotic tissue. These cells produced limited amounts of collagen. Differentiation into immature adipocytes occurred 5 days after the lesion. Small, unilocular adipocytes were located in the necrotic zone by 7 days. Complete restoration of the lesion area was accomplished by 10 days. It is proposed that pericytes act as a reserve cell in the recovery of the rat inguinal fat pad after thermal lesion.
Morphogenesis of the Mouse Coronal Suture
Authors: Johansen VictorA. , Hall Stanton H.
Published: July 2008

The morphogenesis and maturation of the coronal suture in C57B1-strain mice was studied histologically using light microscopy from day 15 postconception through day 71 postpartum. Early differentiation of the osteoid precursors proceeds centrally within the 7- to 8-cell-thick fibrous ectomeninx beginning in the regions of the ossification centers and extends peripherally toward the future sutural margin. Differentiation into osteogenic cellular elements is marked morphologically by an increased nuclear: cytoplasmic ratio, dark-staining nucleoli and a granular chromatin pattern. This zone of cells, designated the osteogenic induction front (OIF), extends in advance of any identifiable accumulation of osteoid matrix or biomineralization. As the OIFs of the parietal and frontal bones approach, but prior to any physical overlap, they lie in different planes dorsoventrally; the parietal OIF located dorsal to the frontal OIF, a pattern maintained throughout subsequent sutural morphogenesis. Upon physical overlapping of the parietal and frontal OIFs, the fibrous capsule thickens dorsoventrally assuming a ‘fusiform’ configuration. This morphological event, referred to as the ‘fusiform blastema’, has been suggested to presage sutural location and determine the relative vertical position of the bony plates comprising the suture. Our results suggest that this is actually a secondary event, the structure of the suture having already been established with the relative physical overlapping of the respective OIFs.
Desmosomes between Mammotrophs Suggest the Existence of a Functional Syncytium
Authors: Saunders S.L. , Reifel C.W. , Shin S.H.
Published: July 2008

Lactotrophs in the adenohypophysis have the apparent inherent capability to produce simultaneous secretion of prolactin from individual cells. There are two possibilities to account for this synchronized, discrete pulsatile secretion: (1) humoral communication, or (2) cell-to-cell syncytial communication. As a first step in examining the second possibility, we searched for ultrastructural evidence of intercellular contacts. The presence of desmosomes, the conventional junctions that serve to anchor adjacent cells, would be the first step in proving contact between homologous cells. In order to increase the observation of desmosomes, the population of lactotrophs in the adenohypophysis was increased by implantation of capsules containing estradiol in male Sprague-Dawley rats. The adenohypophyses were then examined by electron microscopy for indications of these intercellular bridges. Desmosomes were discovered between lactotrophs, indicating that cell-to-cell contact does exist, and suggesting that the desmosome may help the formation of a syncytium among lactotrophs, either directly or indirectly. Since an ectopic pituitary without direct help from the hypothalamus can secrete prolactin in a pulsatile fashion and since there are desmosomes between lactotrophs, it is possible that the synchronized prolactin release occurs through a direct cell-to-cell communication system which is linked by the desmosomes.
Surface Topography of Cultured Anterior Pituitary Cells of the Rat
Authors: Fazekas Ilona , Bácsy E. , Rappay Gy.
Published: July 2008

Anterior pituitary cells of the adult rat were studied by scanning electron microscopy after 3, 6 and 8 days in culture. Epithelial (parenchymal) cells and fibroblasts could be differentiated by their characteristic cell surface structures and by their associations with each other. The surface of solitary and grouped epithelial cells is uneven and rich in smaller or larger blebs, wrinkles and microvilli. A few solitary cilia were found on the surface of some cells. The individual cells forming epithelial cell groups adhere to each other with numerous, parallel, slender extensions. The fibroblasts found in monolayers have extensions with various lengths contacting other cells or the inert substratum. Microvilli arise in various frequency from their smooth surface. Transmission electron microscopy confirmed the presence of the surface structures detected in the scanning electron microscope.
Scanning Electron-Microscopic Observations of Midtrimester Amniotic Fluid Cells
Authors: Djaldetti M. , Goldman J.
Published: July 2008

The surface ultrastructure of the amniotic fluid cells of 15 healthy women at 17–24 weeks of pregnancy was examined with a scanning electron microscope (SEM). The cell surface showed numerous microvilli of different shapes and sizes. The cell membrane differed at the various stages of pregnancy with a tendency to rarefaction of the microvilli with advancing gestation. Since the cell surface may show alterations following infections or metabolic changes, the possibility of using the SEM as an additional tool for the diagnosis of antenatal diseases of the fetus is discussed.
Protargol Silver Impregnation and Neuronal Selectivity
Authors: Zagon Ian S. , Haring John H.
Published: July 2008

The neuronal selectivity of protargol silver was determined in embedded and cultured nervous tissue by light (LM) and transmission electron microscopy (TEM). Ultra -structurally, silver (85–140 Å in diameter) was found deposited in neuronal, but not glial, perikarya and cell processes. Usually, the silver grains were arranged in elongated arrays that were associated with electron-dense, strand-like structures that correspond to the ‘neurofibrils’ observed in LM; myelin sheaths, mitochondria, Nissl substance, Golgi bodies, synaptic vesicles, and endoplasmic reticulum could be excluded as the basis for neuronal argyrophilia. Unfortunately, the composition of these neurofibrils was obscure because of poor tissue preservation involved with proper impregnation, but they appeared to correspond to microtubules and neurofilaments. Neuronal structures containing a predominance of either organelle were impregnated with protargol. Nuclei and nucleoli of neuronal and nonneuronal cells were densely stained with silver as visualized with LM and TEM. Not every neuron was impregnated with protargol, but under conditions of improper fixation some of these neurons had an electrondense cytoplasm which exhibited a definite affinity for silver. A discussion of protargol selectivity is also presented.
Development of Rotation of Mandibular Premolar Tooth Germs in the Dog
Authors: Esaka Satoshi
Published: July 2008

The development of premolar tooth germs in dogs, particularly their rotation and crowding, was examined on radiographs, dissected specimens of tooth germs, serial sections stained by Masson-Goldner’s technique and reconstructed models. The materials used were the mandibles of 32 puppies from birth to 6 months, and the species was a highly pedigreed Shiba Inu which has no crowding of the premolars in the mature stage. The results obtained are as follows. (1) Rotations and crowdings of premolars, similar to those in brachygnathus dogs and wolves raised in captivity, were observed during ontogenesis of dolichocephalic dogs, whose adult state exhibits no crowding of teeth. (2) The type of rotation was B (the mesial portion is rotated buccally) for the second and third premolars and L (the mesial portion lingually) for the fourth premolar. (3) The rotations of the premolars did not coincide with those of their deciduous predecessors. (4) These rotations appeared in the bud and cap stages of premolars, before the formation of roots of deciduous molars. The premolars developed crowding at 5 months when they increased in dimension.
Histochemical and Ultrastructural Analysis of Developing Adipocytes in the Fetal Pig
Authors: Hausman G.J. , Richardson L.R.
Published: July 2008

Histochemical and ultrastructural aspects of adipocyte differentiation in subcutaneous tissue of fetal pigs were analyzed in a longitudinal study. A matrix of collagen fibers surrounding adipocytes developed after the establishment of a distinct and continuous PAS-positive basement membrane. The degree of plasma membrane invagination and specialization was positively correlated with the extent of basement membrane and collagen matrix formation. Close spatial relationships between narrow, smooth endoplasmic reticulum, plasma membrane invaginations, the surface of lipid droplets and mitochondria were observed in differentiating adipocytes. Histochemical and ultrastructural criteria for the identification of preadipocytes are: (1) perivascular location; (2) mitochondria localized in the Golgi zone; (3) cytosolic glycogen; (4) rough endoplasmic reticulum with cisternae uniformly and approximately 600 Å wide; (5) free ribosomes and few polysomes, and (6) lipid droplets encased by microfilaments. These criteria permitted clear distinction from obvious fibroblasts and macrophages. Other stromal cells were morphologically abnormal. Occasionally, adipocytes and perivascular cells exhibited close intercellular contacts that were morphologically distinct from intercellular contacts between contiguous endothelial cells.
Cell Types of the Pars distalis of the Hedgehog (Erinaceus europaeus L.) Adenohypophysis: Cytological, Immunocytochemical and Ultrastructural Studies
Authors: Girod C. , Lhéritier M. , Trouillas J. , Dubois M P.
Published: July 2008

Staining and histochemical methods, immunofluorescence, and electron microscopy were used to individualize the somatotropic cells in the adenohypophyseal pars distalis of the non-hibernating hedgehog. One cell-type was differentiated; their characteristics at the light and electron microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell-type and the validity of the denomination ‘somatotropic cells’.
Prenatal Cytodifferentiation in the Pars distalis of the Dwarf Mutant Mouse
Authors: Wilson D.B. , Christensen E.
Published: July 2008

The pars distalis of the pituitary gland was studied by means of electron microscopy in 14- to 18-day dwarf embryos (dw/dw) obtained from matings of dwarf homozygotes in which reproductivity was induced by hormone supplementation and pituitary transplants to the renal capsule. At 14 days of gestation the dwarf pars distalis shows fewer granulated cells than in the normal. Although somatotroph-like and mammotroph-like cells are identifiable in the normal pars distalis as early as 15 days, comparable cells are not present in the dwarf. By 17 and 18 days, the dwarf exhibits an ambiguous cell-type with a combination of somatotroph and mammotroph characteristics. At 18 days the dwarf also continues to show numerous nongranulated cells with large aggregates of glycogen, whereas in the normal pars distalis comparable glycogen-containing cells are relatively scarce.
Use of Alizarin Red S for Histochemical Staining of Ca2+ in the Mouse; Some Parameters of the Chemical Reaction in vitro
Authors: Lievremont M. , Potus J. , Guillou B.
Published: July 2008

Alizarin red S (ARS) is used for histological characterization of calcium. In order to improve the conditions of the use of the dye on biological materials, the chemical reaction between ARS and Ca2+ is studied in vitro. In aqueous solution ARS and Ca2+ ions precipitate to form brick-red deposits. For precipitation to occur a neutral pH (4 < pH < 8) is required; the stoichiometric ratio is 1:1. ARS reacts with calcium via its sulfonate and hydroxyl groups. The apparent solubility product is around 10∼7 Na+ and K+ ions do not interfere with equilibrium of the precipitation reaction but Mg2+ and soluble proteins such as bovine serum albumin react with ARS and form soluble complexes which can lead to a decrease in the ARS quantity available to react with the calcium ions.
Species Differences in Vascular Connections between the Adrenal and the Kidney in the Monkey, Human and Dog
Authors: Earle A.M. , Gilmore J.P.
Published: July 2008

Vascular connections occurring between the adrenal gland and the kidney were investigated by using techniques of ligation of renal arteries followed by injection of trypan blue into the thoracic aorta. These connections, which course through the renal capsule to terminate at the renal corticomedullary junction, were confirmed in the dog. Using the same techniques in the monkey and human, vessels could be traced to the renal capsule but did not appear to penetrate this capsule.
Specific Endothelial Granules in Venous Patch Neoendothelium in the Rat
Authors: Cuevas P. , Gutierrez Diaz J.A. , Reimers D.
Published: July 2008

Weibel-Palade bodies were observed in the neoendothelium and capillaries of vasa vasorum of autologous ‘venous patches’ grafted in the common carotid artery of the rat. These corpuscules varied in number and distribution but were most frequently found in the luminal area of endothelial cytoplasm. In venous patch neoendothelium, the shape, size and substructure of Weibel-Palade bodies were similar to those in other types of vascular endothelium. These specific endothelial granules were more numerous during the week following neoendothelium formation. It is proposed that these corpuscules may play a role in the proliferation of endothelial cells in venous patches.
Chlorpromazine and Temperature-Induced Changes in Cultured Mouse Cardiac Tissue
Authors: Kalmus G.W. , Webb L.A.
Published: July 2008

Fetal mouse heart explants were cultured at 4 and 37 °C with or without chlorpromazine hydrochloride. Histological observations showed that tissue integrity was maintained at 4°C without or 37 °C with drug treatment. Tissue disintegration was observed at 4°C with drug treatment or 37 °C in the absence of the drug.
Effects of Experimental Bipedalism on the Growth of the Femur and Tibia in Normal and Hypophysectomized Rats
Authors: Simon M.R. , Papierski P.
Published: July 2008

Male and female Sprague-Dawley rats were used to see if increased, intermittent, compressive forces, produced by experimental bipedalism would have a compensatory effect on hypophysectomy – a situation known to inhibit bone growth. Half of the rats underwent amputation of both front legs at 10 days of age; and at 21 days of age, half of the normal and half of the bipedal rats underwent hypophysectomy. All rats were sacrificed at 55 days of age, and weighed. The femora and tibiae were removed, cleaned, fixed, weighed and measured. The results of this study suggest that increased, intermittent, compressive forces may be instrumental in increasing long bone growth among adolescent females.
Glycosidases and Lipid Metabolism in the Central Nervous System of the Hedgehog (Paraechinus micropus)
Authors: Sood P.P. , Mohanakumar K.P. , Chauhan A.K.
Published: July 2008

The distribution of β-galactosidase and β-glucuronidase in the forebrain of the hedgehog is similar to that of phospholipids. Both enzymes and the phospholipids are mainly localized in the fibrous components. Their distributional patterns are also identical to that of myelin. The functional significance of enzymes in lipid and myelin metabolism is discussed.
Retinal Projection to the Inferior Colliculus in the Rat
Authors: Yamauchi Koh-en , Yamadori Takash
Published: July 2008

A few retinal fibers projecting to the contralateral inferior colliculus were observed in the albino rat by means of the silver impregnation and HRP methods. After passing through the stratum opticum of the superior colliculus, these fibers pass via the anterior pole to the dorsal and lateral parts of the colliculus. The fibers to the dorsal part run upward in the superficial layer of the colliculus, and the fibers to the lateral part turn lateralward at the anterior pole. In 1 case a few fibers projecting to the posteromedial part of the colliculus were also observed.