bluuebunny/crossref_metadata_2025 huggingface dataset:
Body and organ weights and linear measurements of the adult Mongolian gerbil
Authors: Kramer A. W.
Published: February 2005

Data were collected from a colony of 49 male and 55 female two‐year‐old Mongolian gerbils, Meriones unguiculatus (Milne‐Edwards, 1867). This report gives tables which present data regarding linear measurements of body and organs and absolute and relative organ‐weight data. The means, standard deviations, ranges, and coefficients of variation were summarized in the tables. Grossly observed pathological organs were omitted from the study. The tables give information about this species which could be helpful in future laboratory investigations where the body‐and organ‐weight ranges, variability and linear measurements of this species may be of practical value.
Marginal bands in nucleated erythrocytes
Authors: Maser Morton D. , Philpott Charles W.
Published: February 2005

Marginal bands from erythrocytes of several non‐mammalian vertebrates were studied by light and electron microscopy. Cells were observed in thin sections after various fixing procedures and in wholemount preparations. Isolated marginal bands were prepared by air drying and freeze drying. The marginal bands are composed of tubular elements which vary in diameter from 200 Å to 500 Å, depending on the preparation method. It is suggested that these tubules are part of a general class of microtubules, and that the real diameters of microtubules are approximately twice those observed in fixed and sectioned material.
The culture and karyotype of rat lymphocytes stimulated with phytohemagglutinin
Authors: Rieke William O. , Schwarz M. Roy
Published: February 2005

A simple method leading to growth and mitosis in over 95% of shortterm cultures of lymphocytes from the blood, lymph or thymus of the rat is described. The method which is modified from Moorhead's original technique (′60) employs standard tissue culture medium (Eagles MEM or TC no. 199), 20% fresh rat serum, washed lymphocytes, penicillin, and phytohemagglutinin‐P (0.01 cm3/cm3 of culture of a 1:5 dilution of stock solution). Details of culture technique and factors contributing to growth failures are discussed.

The chromosomes of male and female Lewis rats were studied in metaphase spreads of cultured cells. The karyotypes of these rats are presented and found to be in agreement with those recently reported by Hungerford and Nowell (′63).
Hemodynamic factors in the development of the chick embryo heart
Authors: Jaffee Oscar Charles
Published: February 2005

Blood flow patterns have been outlined in the chick embryo heart. The initial flow pattern adapts to the heart form but soon vascular forces affect cardiogenesis. Spiralling of the blood streams in the sinus venosus appears to lead to an expansion of this chamber. The atrial septum forms between parallel streams and evidence is presented that blood flow contributes to septation. Interatrial flow develops with a fusion of the inflow streams bringing the entire systemic venous return into the right atrium when the left atrium receives a small pulmonary return; the difference in pressures is believed to lead to perforation of the septal wall.

The ventricular septum also forms between parallel bloodstreams. Inhibition of the left ventricular outflow, brought about by the application of trypan blue to the embryos, was associated with the production of ventricular septal defects. Higher pressures in the left ventricles, brought about by increased vascular resistance to these chambers, led to the defects as evidenced by left to right flow through the defects. An interpretation of the origin of this common congenital anomaly is thus offered.
Development of the rat palate
Authors: Coleman R. D.
Published: February 2005

Normal fetuses 13‐to‐21 days of age were obtained from female Long Evans Rats maintained on a stock diet known to produce normal offspring. Cleft palate fetuses were produced from mothers fed the same diet supplemented with 100 mg of pyrimethamine per kg of diet for four days beginning on the tenth day of gestation. The heads were studied with the low‐power microscope and serial histologic sections.

In normal fetuses the lateral palatine processe appeared to form the roof of the mouth by two distinct mechanisms. Palatal closure was achieved rostrally by rotation of the lateral palatine processes from a ventromedial to a horizontal position while caudally, it resulted from the fusion of outgrowths from the medial surfaces. The original free ventral edges of the lateral palatine processes in the caudal region largely underwent regression by the seventeenth day. Closure commenced in the anterior third of the palate and proceeded rostrally and caudally.

In the fetuses with cleft palate induced by pyrimethamine, the lateral palatine processes were observed in various stages of rotation or transformation depending on the region of the palate examined. The narrow width of these processes suggested that the antimetabolite had suppressed their growth at a critical stage in development. The results suggested certain similarities in the mechanisms of palatal closure in rat and man.
Cerebral intervascular strands of connective tissue as routes of transportation
Authors: Cammermeyer Jan
Published: February 2005

In the facial nucleus of the rabbit, fixed by a procedure of perfusion with delayed autopsy, intervascular strands of connective tissue contain on rare occasions either minute red PAS‐stained granules or clear vacuoles. With increasing age, the strands are transformed into homogeneous connective tissue bands.

On the basis of these microscopic observations, it is inferred that, in younger animals, soluble and insoluble products can be channeled via the intervascular strands to adjacent blood vessels.
The Innervation of the joints of the wrist and hand
Authors: Gray D. J. , Gardner Ernest
Published: February 2005

The nerve supply of the joints of the wrist and hand was studied in dissections and in serial sections of fetal hands stained with silver.

The radiocarpal joint was supplied mainly by branches of the anterior and posterior interosseous nerves.

The inter‐carpal and mid‐carpal joints were supplied anteriorly by the anterior interosseous, median, and ulnar nerves, and by the deep branch of the ulnar nerve. Most of these joints were supplied posteriorly by the posterior interosseous nerve.

Anteriorly the carpometacarpal joints were supplied by the ulnar nerve and its deep branch. Posteriorly they received fibers from the nerves running distally on the back of the hand. The deep branch of the ulnar nerve supplied all inter‐metacarpal joints.

The metacarpophalangeal and interphalangeal joints were supplied mainly by the palmar digital nerves. The metacarpophalangeal joints also received fibers from the dorsal digital nerves and from the deep branch of the ulnar nerve. The interphalangeal joint of the thumb, the proximal interphalangeal joint of the index finger, and both interphalangeal joints of the little finger received fibers from the dorsal digital nerves.

The articular branch of the superficial branch of the radial nerve, first described by Winckler, was distributed to some of the inter‐carpal and carpometacarpal joints on the lateral side of the wrist.
Electron microscopy of serial sections of the murine glomerular mesangium
Authors: Shimamura T. , Sorenson George D.
Published: February 2005

An electron microscopic study of serial and/or closely spaced step sections of the murine glomerular mesangium is reported. Photomicrographs were obtained from sections which extended through mesangial cells from one side to the other. These cells are separated from the capillary by matrix as well as overlying endothelial cells and from the epithelium by matrix and basement membrane.

The observations clearly demonstrate the presence of a “third” type of cell within the murine mesangium which is separate and distinct from endothelium and epithelium.
Persistence of the axis artery of the lower limb
Authors: Blair Charles B. , Nandy Kalidas
Published: February 2005

Three negro cadavers examined during routine dissection showed remnants of the axis artery acting as important adult arterial routes through the lower extremity. In two of the three cases, the anomalous condition involved persistent ischiatic portions of the axis artery continued into the genicular region as the popliteal artery. In these cases, the function of the much reduced femoral artery was assumed by an over‐developed profunda femoris artery which, with its perforating branches, then entered the persistent ischiatic artery to give rise to the popliteal.

In one of these cases, the infragenicular circulatory pattern was completely typical.

In two of the three cases, one of which is included above, the anomalous condition of the axis artery involved the infragenicular circulatory pattern. In these, two anomalous conditions were obvious: (1) the peroneal artery rather than the anterior tibial, which was incomplete distally, carried the blood supply to the dorsalis pedis artery, and (2) the peroneal artery, by virtue of its position relative to the tibialis posterior muscle, represented the old interosseous part of the axis artery distal to the ramus communicans medius rather than the more recently developed superficial peroneal artery.

The sequence of embryonic development of the arterial supply of the lower extremity is presented along with comments as to the cause and time of origin of the anomalous conditions presented herein.
The skin of the mole (Scapanus townsendii)
Authors: Giacometti L. , Machida H.
Published: February 2005

The skin of the mole (Scapanus townsendii) has the following characteristic features. (1) The epidermis is thin over the general body surface and very thick on the palms and muzzle. On the snout the epidermis has the specialized end‐organs of Eimer. (2) The dermis has no papillary body, and few elastic fibers, except in the eyelids where elastic fibers are more numerous. The arterioles in the deep dermis are surrounded by nerve filaments which are positive for alkaline phosphatase. (3) In the hairy skin, the apocrine sweat glands are large and numerous, the ducts opening upon the surface and not inside the pilary canals. The secretory epithelium of the glands contains alkaline phosphatase, but no cholinesterase. (4) There are approximately 3,000 hairs per cm2, and each hair follicle is surrounded by an end‐organ which contains alkaline phosphatase. (5) The small and spherical sebaceous glands are similar to those of the rodents.
The preparation of injected and cleared “whole‐mounts” for the study of topographical anatomy
Authors: Hughes Trevor
Published: February 2005

A simple method is described for the preparation of cleared and injected “whole‐mounts” of large masses of tissue (for example the mediastinal contents). This technique allows the use of high magnifications during examination and microphotography and the use of histological controls. It provides a novel method for detailed topographical studies because each tissue has its own distinctive vascular pattern which delineates it clearly.

A direct three‐dimensional inspection has many advantages over the usual methods of dissection, or reconstruction from serial sections. This is particularly true of microcirculations, fine autonomic nerve patterns and the distribution of aberrant tissues (thyroid, parathyroid, etc.). Other distinctive features of tissues, such as positive chromaffin staining or the uptake of injected substance by the reticulo‐endothelial system, can also be demonstrated.

The results obtained are demonstrated by photographs of “whole‐mounts” from dogs and adult and fetal cats. The advantages and disadvantages of the method are discussed.
Microanatomy and intramural physical forces within the coronary arteries (man)
Authors: Boucek Robert J. , Takeshita Ruth , Brady Al H.
Published: February 2005

The osita of the left and right coronary arteries differ as to location, the distribution of surrounding muscle bundles, and in the extension of aortic elements into the proximal segments of the vessels. The muscle of the media of the right coronary artery is composed of thick bundles describing a helical contour and arranged in repetitive segments. Multiple muscle bundles make up the media of the anterier descending and circumflex arteries, and each bundle arises separately from different quadrants of the adventitia. Contraction of the muscle bundles may generate intramural physical forces. Ostial regions, sites of nearly continual deformation from the pulse wave, develop focal physical forces. Accentuation of these physical forces may occur in certain regions and result in the alteration of the histology of the artery by depositing connective tissue elements.
Histological and ablation studies on the relation of the subcommissural organ and rostral midbrain to sodium and water metabolism
Authors: Brown Donald D. , Afifi Adel K.
Published: February 2005

Fourteen mature male rats were fed a sodium‐deficient diet for six weeks. After three weeks on the diet, electrical ablations were made in the region of the subcommissural organ. During the six‐week period measurements were made of water intake, urine output, and urinary sodium output. A second group of five one‐month‐old male rats was given the sodium‐deficient diet and seven litter‐mates a control diet. Five months later, the adrenals and subcommissural organs were studied histologically. The results obtained indicate that: (1) subcommissural organ ablation does not change urinary sodium excretion; (2) sodium deprivation, although producing significant changes in the width of the adrenal zona glomerulosa, does not affect the periodic acid‐Schiff reactive material in the subcommissural organ; (3) complete subcommissural organ ablation is associated with decreased urine output and water intake; (4) partial subcommissural organ ablation combined with destruction of structures in and around the rostral periaqueductal gray matter and adjacent diencephalon is associated with increased urine output and water intake; (5) lesions which failed to involve significantly the aforementioned areas are associated with no change in urine output or water intake.
Correlation of retinal cytoarchitecture and ultrastructure in Golgi preparations
Authors: Stell William K.
Published: February 2005

A simple procedure is described for obtaining both cytoarchitectural and ultrastructural information about nervous tissue. Freshly excised fish retinas were impregnated by a modification of Cajal's rapid Golgi procedure, embedded in Epon, sectioned at 80 μ, and scanned by light microscopy. Isolated well‐impregnated cells were selected for further study and remounted for ultrathin sectioning. The appearance of 80‐μ, 1‐μ, and ultrathin sections was correlated.

The material responsible for Golgi impregnation is a water‐soluble, electron‐dense precipitate which usually fills the cytoplasmic ground substance but does not penetrate the plasma membrane or membrane‐bound organelles. Preservation of ultrastructure of spared organelles permits identification of cells. Since the precipitate does not encrust the outer surface but is contained within the plasma membrane, it does not obscure fine‐structural relationships between cells. The method has demonstrated the complex relations of horizontal and bipolar cell processes to the receptor synaptic terminals.

While less comprehensive than three‐dimensional reconstruction from serial ultrathin sections, this method is much simpler, and is useful for surveying larger amounts of tissue. It may be particularly advantageous for investigating ultrastructural relationships of cell processes which are so long as to prohibit such reconstruction.
Livers of choline‐deficient pregnant and fetal rats
Authors: Meader Roland D.
Published: February 2005

A group of 30 pregnant rats was subdivided into three experimental groups of ten animals each. The first and second received choline‐deficient and choline‐supplemented diets respectively during the usual 21 days of gestation. The third was fed a choline‐deficient diet an additional 30 days prior to insemination, and subsequently during the usual period of gestation.

Groups of ten non‐pregnant animals received the choline‐deficient and choline‐supplemented diets respectively for 21 days, a period comparable to that of gestation.

Choline supplementation of the basal (choline‐deficient) diet resulted in a complete absence of stainable lipid in the livers of pregnant and fetal rats.

The stress effects of pregnancy on increased susceptibility to choline deficiency were assessed by comparing the amount of stainable fat (in frozen sections) in the livers of pregnant rats maintained on the choline‐deficient diets during the period of gestation with that in livers of non‐pregnant rats fed the deficient diet for the same length of time.

Under the conditions of this experiment, the stress effects of pregnancy increased susceptibility to choline deficiency, as evidenced by the increased accumulation of fat in both maternal and fetal livers.
Histological comparison of the thymus of germfree (axenic) and conventional CFW mice
Authors: Bealmear M. , Wilson R.
Published: February 2005

The histology of the thymus of both germfree and conventional mice at days 0, 14, 50, and 168 supports the interpretation of the growth pattern of the thymus as a reflection of the lymphocyte population of the cortex and medulla. In general the conventional thymus has more small lymphocytes in the cortex and more lymphocytes migrating into the medulla than in its germfree counterpart. Hence it would seem that antigenic challenge stimulates lymphocyte production in the thymus cortex and initiates a chain of events that may eventually result in thymus lymphocytes populating the other lymphoid tissues of the body, or that may result in lymphocyte degeneration in the thymus and the subsequent releas of a humoral factor that may stimulate the other lymphoid tissue to lymphocytopoiesis.
Development of the human renal glomerulus I. Differentiation of the filtering membrane
Authors: Aoki Agustin
Published: February 2005

The development of the human renal glomerulus, in particular its filtering membrane, has been studied by light microscopy with a high resolution technique as a necessary and complementary step for electron microscopical studies.

The glomerular filtering membrane is a triple layered structure composed of the visceral epithelium, the capillary endothelium and a basement membrane interposed between them. These three layers have different and definite origins in the metanephrogenic blastema, but close interdependency during the developmental process exists. Mesenchymal cells were demonstrated migrating from the renal interstitium into the invaginating wall of the renal vesicle and transforming into the endothelial and mesangial cells. The visceral epithelium originates from the invaginated wall of the primitive renal vesicle and is transformed from a mass of cells into a special membrane concomitant with the differentiation of the capillary loops. The basement membrane is produced later by the close association of the other two cellular layers.
The cranial attachment of the sphenomandibular (tympanomandibular)ligament
Authors: Burch James G.
Published: February 2005

The sphenomandibular (tympanomandibular) ligament develops from Meckel's cartilage between the future petrotympanic fissure and the mandibular lingula. The superior attachment of this ligament has been described to attach to the sphenoidal spine.

Fifty‐one cadaver half heads were dissected to study the superior attachment of this ligament. Forty‐five of the 51 ligaments were found to be attached in the area of the petrotympanic fissure, not directly to the sphenoidal spine. Six of the specimens had a thin fibrous slip which fanned out medially to the sphenoidal spine.

Twelve additional cadaver specimens were decalcified and cut in various planes through the temporomandibular joint. All specimens showed a fibrous continuation of the ligament through the petrotympanic and/or squamotympanic fissures with an attachment to the malleus in the middle ear. When tension was applied to the ligament the malleus was seen to move.

A 115 mm human fetus head was dissected. A ligamentous structure was seen to run from the medial side of the mandibular ramus to the future squamotympanic fissure area. When observed microscopically the ligament was continuous through the fissure and attached to the malleus.
An intercellular substance in rat cerebral cortex: Submicroscopic distribution of ruthenium red
Authors: Bondareff William
Published: February 2005

Specimens of rat cerebral cortex were fixed in solutions containing ruthenium red and prepared for electron microscopy by a method described by Luft ('65a). In specimens taken from a narrow zone 5–10 m̈ thick and about 5 m̈ beneath the pial surface the ruthenium red reaction was found to be uniform and reproducible. In this zone a particulate reaction product was distributed extracellularly. The reaction product accumulated in intercellular gaps, filling them with closely‐packed, dense particulates which adhered closely to the outer leaflets of apposed plasma membranes and filled also the intercellular spaces with additional particulates.

The selective, extracellular distribution of the ruthenium red reaction product suggested the presence of an intercellular acid mucopolysaccharide, which may be different in capillary basal laminae, intercellular gaps and synaptic clefts, as suggested by the variable reactivity of these extracellular sites.

The presence of an intercellular acid mucopolysaccharide in the cerebral cortex would controvert neither ion transport by glial cytoplasm nor intercellular channels. It is suggested that such an intercellular substance might facilitate ion transport and the histophysiological significance of this is discussed.
The fine structure of the ductuli efferentes of the opossum
Authors: Ladman Aaron J.
Published: February 2005

The fine structure of the straight portions of the ductuli efferentes of the opossum were studied by light and electron microscopy. Two cell types, a ciliated and non‐ciliated cell, characterize the simple columnar epithelium that lines the ductuli. The non‐ciliated cell possesses an extraneous coating of the luminal plasma‐lemma, aggregations of apical canaliculi, and vacuoles of varying density distributed in the supranuclear cytoplasm. Such morphological criteria have been regarded as suggestive evidence for absorptive function. The epithelium rests upon a thick basement membrane beneath which are variable amounts of smooth muscle and connective tissue elements.

Observations of the structure of the simple squamous epithelium lining the processus vaginalis are reported.

Myelinated and unmyelinated nerves are found in the adnexa of the ductuli. These are enclosed in a thin, cellular investment, the innermost layer of which is usually incomplete. This cellular wrapper is considered a “perineural epithelium” but its characteristics are at variance with those found in the recent literature.
Cell architecture in the papillary layer of rat incisor enamel organ at the stage of enamel maturation
Authors: Kallenbach Ernst
Published: February 2005

Shape and arrangement of cells and extent of intercellular spaces were studied in sections of enamel organ cut in three planes: at right angles to the axis of the incisor tooth, at right angles to the axis of the ameloblasts, and parallel to the axes of the incisor and ameloblasts.

The cells in contact with the base of the ameloblasts make up the proximal part of the papillary layer. They have a polygonal cross section close to the ameloblasts and point several sheet‐like cell processes towards the blood vessels which invaginate in the papillary layer. Intercellular spaces of constant width pervade the proximal part and provide a direct and straight communication between blood vessels and ameloblasts.

The cells of the ridges make up the distal part of the papillary layer, and are flattened in the direction of the ridges. Intercellular spaces in the ridges are narrower than in the proximal part and visible with the light microscope only during a fraction of the enamel maturation period.

No distinct cell layers are visible within the papillary layer during enamel maturation. All cells in the papillary layer may be in contact with the basement membrane investing the enamel organ. The structure of the papillary layer changes with the different phases of enamel maturation. Functional aspects of the papillary layer are briefly discussed.
Congenital malformations in nonhuman primates: Spontaneous and experimentally induced
Authors: Wilson James G. , Gavan James A.
Published: February 2005

An attempt to survey spontaneous teratogeny among nonhuman primates bred under laboratory conditions revealed interesting but nonconclusive results. Data on controlled breeding in 2950 animals representing 12 species yielded an estimated incidence of 0.44% malformations. No indication was found that other primates display more malformations than man, and the limited information available suggests that there may be fewer spontaneous defects in nonhuman forms.

Macaques and baboons appear to respond in a similar manner and to the same types of extrinsic agents as does man. Thalidomide, Rubella virus and androgenic hormones produce similar defects in comparable dosage at equivalent stages in development in both groups. Several other agents thought not to be teratogenic in man have been realistically tested in primates and also found to be non‐teratogenic.

Using thalidomide an attempt was made to determine the degree of sensitivity and delimit the susceptible period of Macaca mulatta to this drug. Typical limb malformations were obtained with a single dose of as little as 16 mg/kg between the twenty‐fifth and thirtieth days of gestation. Comparable doses at earlier and later ages were without effect, thus defining the susceptible period. In addition, evidence of a positive dose‐response relation and of a cephalocaudal gradient in teratogenesis was obtained.
The premaxilla: Embryological evidence that it does not exist in man
Authors: Wood Norman K. , Wragg Laurence E. , Stuteville Orion H.
Published: February 2005

Many accounts of the human premaxilla describe its ossification centers and time of fusion with the maxilla, but that such a bone even exists in the human has long been questioned. Very few specimens undergoing initial phases of ossification have been reported and no convincing photographs of separate centers have been published.

This report is based on 90 serially sectioned human embryos whose ages (Streeter's Horizons XVIII to XXIII) were closely grouped around the age when ossification of the upper jaw begins. There is but one ossification center bilaterally which, although it appears first in the cuspid region, rapidly involves an area extending from the molar to the central incisor region.

Not one of the specimens showed an independent center for the “premaxilla” nor an “incisive suture” in the area of ossification. The premaxilla does not exist as an independent bone in man.
The distribution of nerves in human primary teeth
Authors: Rapp Robert , Avery James K. , Strachan Donald S.
Published: February 2005

Human primary teeth in the stages of late root formation, root completion and root resorption were impregnated with silver to allow study of the distribution of nerves in the pulp.

Neural trunks composed of many individual, myelinated nerve fibers enter the apical foramen of primary teeth and pass in a coronal direction, often in close association with blood vessels. Neural trunks in the crowns of the teeth divide into smaller branches, which divide further into myelinated nerve fibers, which become interwoven to form the parietal layer (plexus of Raschkow). An occasional unmyelinated fiber leaves this zone and passes into the odontoblastic layer of cells where it appears to terminate with no specialized ending apparent. No nerves were seen to enter the predentin or dentin.

As primary teeth begin to undergo root resorption, degenerative changes such as thickenings, varicosities and fragmentation appear in the nerves. The quantity of neural tissue also decreases. The greater the amount of resorption, the greater are the degenerative changes. In teeth in which the roots are almost completely resorbed, only a small number of nerves remain.

The pattern of distribution of nerves in primary teeth is observed to be similar to that of permanent teeth. The density of the innervation of the primary teeth, however, is not found to be as great as that of permanent teeth.
A technique of decalcification suited to electron microscopy of tissues closely associated with bone
Authors: Baird Irwin L. , Winborn William B. , Bockman Dale E.
Published: February 2005

Systematic experiments have resulted in a method of decalcification which, although specifically developed for cytological study of reptilian aural tissue, should be applicable to other problems involving electron microscopy of organic components of bone or tissues closely associated with bone. Reptilian otic capsules and control specimens of mammalian hepatic tissue were subjected to planned variations of fixatives and decalcifying agents, embedded, sectioned, and evaluated by light and electron microscopy. Additionally, applicability of the more satisfactory agents to other mammalian tissue was checked by limited testing on specimens from Mongolian gerbils. Acceptable results were achieved in tissues fixed in glutaraldehyde, and then decalcified in cold 0.1 M solutions of disodium or tetrasodium EDTA (adjusted to pH 7.2–7.4 with sodium hydroxide or versenic acid, respectively), containing 4.0% glutaraldehyde; following decalcification, specimens were washed in buffer, postfixed in osmium tetroxide, and embedded in epoxy resins with minor modification of standard techniques. Acceptable cytological detail and morphological relationships were retained, and extended treatment with the decalcifying solution did not apparently result in degradation of tissues.
A study of the interosseous distance between the radius and ulna during rotation of the forearm
Authors: Christensen John B. , Adams John P. , Cho K. O. , Miller Lawrence
Published: February 2005

A roentgenological and gross anatomical study of the variation in the interosseous distance between the radius and ulna during the rotation of the forearm was made on cadavers. It was found that the neutral position provides the widest interosseous distance at different levels of the forearm compared with all other supinatory and pronatory positions. The average of the interosseous distances is greatest at the junction of distal and middle thirds of the radius, except in pronation 90°.

Our observations show that the magnitude of the interosseous distance is largely proportional to the radius and ulna being in the same plane in a particular position of rotation of the forearm. In the neutral and supinatory positions, the point of the widest interosseous distance occurs more frequently in the middle third of the forearm, and in pronatory positions, in the distal third. Observations were also made on ligamentous specimens for the variation of tension of the interosseous membrane and of various planes occupied by the radius and ulna at different positions of rotation. The interosseous membrane was found to be taut in the neutral position in its major portion but lax in both pronation and supination.
The localization of mitotic figures in regenerating mouse liver
Authors: Melvin Joan B.
Published: February 2005

The number of mitotic figures present at one time in regenerating mouse liver, 48 hours after injury with CCI4, was increased by administration of colchicine. The livers were injected with india ink at the time of sacrifice to outline the blood vessels, and histological sections were made. Microscopic examination supported by statistical studies indicated that mitotic figures do not occur at random at this time in regenerating mouse liver. The dividing cells were found in close proximity to the terminal twigs of the branch of the portal vein in zone one of the functional lobule described by Rappaport.
Cell migrations to the isocortex in the rat
Authors: Hicks Samuel P. , D'Amato Constance J.
Published: February 2005

Cells that took up tritiated thymidine (H‐3T) at various periods of intrauterine and early infant life in the periventricular proliferative zone and migrated to form the isocortex in the rat were tracked autoradiographically in series of stages to characterize their movements. Cells labeled at any stage soon separated themselves into cohorts, some continuing to proliferate, others migrating at once, and still others delaying before migrating. Migratory cells moved to the developing cortex along the curved and oblique paths of the pallial fibers, whose basic plan was established by the early thalamocortical fibers. Magnitude of speed was 15 to 30 μ per hour. The primitive neural cells that originated on each of the fourteenth to eighteenth intrauterine days first reached the cortex in about 48 hours, others took two or three days longer. Migrations originating on the nineteenth to twenty‐first days continued into the week after birth; as the primitive cells approached the cortex, however, they differentiated into young neurons, and traveled perpendicularly to its outer part. The first cohort of twentieth day labeled cells reached their intracortical destinations in about three days, the last in about ten days. The isocortex was formed essentially from within outward. The first neuroglia destined for the isocortex arose on the twenty‐first intrauterine day.
On the presence of peripheral‐like nervous and connective tissue within irradiated spinal cord
Authors: Gilmore Shirley Ann , Duncan Donald
Published: February 2005

Cells with elongated nuclei resembling those of fibroblasts and/or Schwann cells had been noted previously in x‐irradiated portions of rat spinal cords. The present experiment was undertaken to determine the identity and fates of these cells. For this experiment, a 5 mm length of lumbosacral spinal cord was irradiated (4000 R) in three‐day‐old Holtzman rats. Groups of these rats and their litter mate controls were killed at intervals from 11 through 60 days following irradiation. Most of the spinal cords were prepared for light microscopic examination; a few were prepared for ultrastructural studies. Light microscopic examination revealed that the cells in question became observable near the dorsal roots within and immediately caudal to the irradiated area in a few rats as early as 15 days post‐irradiation and in all rats by 19 days following irradiation. The number of cells increased rapidly and in some cases filled the dorsal funiculi. Axons that were intermingled with these cells usually became myelinated approximately 25 days post‐irradiation. The myelin that formed on these axons resembled peripheral rather than central myelin. Reticular fibers were also abundant in the cell aggregations. The ultrastructural studies confirmed these observations. The data indicate that these cells were involved in formation of peripheral‐like nervous tissue within the spinal cord of all irradiated rats.
Electromyography and cinematography of leg and foot (“normal” and flat) during walking
Authors: Gray Edwin G. , Basmajian John V.
Published: February 2005

Electromyography with fine‐wire electrodes and special equipment for synchronized motion pictures were used to study six muscles of the leg and foot during walking in five different ways in ten “normal” and ten flatfooted subjects. Detailed analyses and comparisons of the two groups are described and discussed.

Tibialis Anterior has two peaks of activity at heel‐strike and toe‐off of the stance phase; is inactive during mid‐swing and middle of the stance phase; is active at full‐foot in flatfooted subjects, and generally more active during toe‐out and toe‐in walking. Tibialis posterior is inactive through the swing phase. In flatfooted persons it becomes activated at heel‐strike and more active at full‐foot during level walking. The toe‐out position reduces its activity. Flexor hallucis longus is most active in mid‐stance; during toe‐out walking, activity increases in both phases, generally being more active in “normal” persons. Peroneus longus is most active at mid‐stance and heel‐off and generally more active in flatfooted persons. Abductor hallucis and Flexor digitorum brevis are generally more active in flatfooted persons. An important regular pattern of inversion and eversion during the walking cycle is described. Contingent arch support by muscles rather than continuous support is the rule, muscles being recruited to compensate for lax ligaments and special stresses during the walking cycle.
The innervation of the joints of the foot
Authors: Gardner Ernest , Gray D. J.
Published: February 2005

The nerve supply of the ankle joint and of the joints of the foot was studied in dissections of fetal and adult feet and in serial sections of fetal feet stained with silver.

The ankle joint was supplied by the tibial, sural, deep peroneal, and saphenous nerves, and by the accessory deep peroneal nerve when present.

The tarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves, and on their dorsal aspects chiefly by the deep peroneal nerve. The joint between the lateral and intermediate cuneiform received branches from the intermediate dorsal cutaneous nerve also. The lateral dorsal cutaneous nerve and the accessory deep peroneal nerve when present provided additional branches to the subtalar and calcaneocuboid joints.

The tarsometatarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves. Most of them were supplied on their dorsal aspects by the deep peroneal nerve, but the cuboid‐metatarsal joints received their supply from the intermediate dorsal cutaneous nerve. The intermetatarsal joints had a similar but sparser supply. The joint between the fourth and fifth metatarsal received branches from the intermediate dorsal cutaneous nerve.

The plantar digital nerves provided the main supply to the metatarsophalangeal joints. The dorsal aspect of the first metatarsophalangeal joint was supplied by the deep peroneal and the medial dorsal cutaneous nerves, of the second metatarsophalangeal joint by the deep peroneal nerve, and of the fourth and fifth metatarsophalangeal joints by the lateral dorsal cutaneous nerve. The interphalangeal joints did not receive articular branches from the dorsal digital nerves, except in the case of the interphalangeal joint of the big toe, which was supplied by the deep peroneal and the medial dorsal cutaneous nerves.
Formation of the redundant nuclear envelope in monkey spermatids
Authors: Franklin Luther E.
Published: February 2005

Development of redundant nuclear envelope was observed in Erythrocebus patas and Macaca mulatta spermatids.

As the acrosome forms around the anterior part of the nucleus, the underlying nuclear envelope becomes more dense in appearance. Changes which lead ultimately to formation of the redundant nuclear envelope of mature spermatozoa involve only the posterior region of the envelope which does not lie beneath the acrosome.

The first recognized change is separation of the nuclear envelope from underlying chromatin by an intervening band of lightly stained nuclear material, around the posterior quarter of the nucleus. The separation increases and the bulged region of the nuclear envelope is drawn caudally as nuclear condensation progresses. The caudally extended region of the nucleus is comprised of nuclear material of low electron density and pores are present in the envelope of the extended areas.

The chromatin aggregates in late spermatids becomes homogeneous in appearance when the nucleus flattens into a paddle shape. Nuclear protrusions are present at both posterior corners of the flattened nucleus at this stage of spermiogenesis but only one protrusion is well developed. Membrane remnants of the extended nuclear envelope remain in mature spermatozoa as the redundant nuclear envelope.
The compressive properties of single osteons
Authors: Ascenzi Antonio , Bonucci Ermanno
Published: February 2005

The compressive strength of single human osteons has been investigated in specially prepared samples using a microtesting machine equipped with a microwave micrometer. The main conclusions which can be drawn from our results are: (1) In agreement with Gebhardt's theories the ultimate compressive strength is greatest for osteons having transversally oriented fiber bundles, lowest for osteons having longitudinally oriented fiber bundles, and intermediate for osteons whose fiber bundles change direction in successive lamellae through an angle of about 90°. (2) The modulus of elasticity is greatest in osteons with transversally oriented fiber bundles. (3) With all three types of osteon the stress‐strain curves for fully calcified osteons are markedly different from those for osteons with low calcium content, the modulus of elasticity being much lower in osteons of the latter type. (4) Age seems to have no measurable influence on the compressive properties of osteons. (5) The comparison of compressive properties in single osteons and in macroscopic bone samples seems to support the view that the osteon is actually the mechanical unit of compact bone. (6) Fracture in osteon samples starts with microscopic fissures induced by shearing. (7) In every case these fissures form an angle of roughly 30°–35° with the axis of the osteon and do not appear to vary with the microscopic osteon structures. (8) Electron microscopy reveals distortion of bone crystals and breaking of collagen fibrils at the edges of the fissures.
The origin and survival of gastric parietal cells in the mouse
Authors: Ragins H. , Wincze F. , Liu S. M. , Dittbrenner M.
Published: February 2005

Using microradioautography, the origin of the gastric parietal (and zymogen) cells was deduced by observing the time of appearance of labelled parietal cells in relation to the other labelled cells in the gastric mucosa. In order to see whether the parietal cell divides in the adult mouse, time grain count curves of the labelled parietal cells were made from animals which were killed at 1–291 days after thymidine 3H injection DPT). Parietal cell survival was followed by observing the disappearance of the labelled parietal cell population. Parietal cells appear to be entirely derived from other cells since a significant number of labelled parietal cells does not appear unless the animal is allowed to survive for several days. Parietal cells do not appear unless the animal is allowed to survive for several days. Parietal cells do not seem to undergo mitosis in the adult mouse because the time grain count curves did not shift with time. Although a few labelled parietal cells persisted in the 291 DPT animals, a large majority of the labelled parietal cells disappeared by 90 DPT and had a half life of roughly 23 days. This suggests an element of renewal for the parietal cell population.
The fine structure of subsurface cisterns
Authors: Siegesmund K. A.
Published: February 2005

Structures identified as subsurface cisterns (SSC's) have been observed in a variety of nerve cells from several different species. The SSC's occurred only in neurons and were most often opposite what appeared to be glial cells. Upon acrolein‐glutaraldehyde fixation, they appeared as distinct cytoplasmic organelles consisting of a short 0.5 μ long pentalaminate membrane in close parallel to the neuronal plasmalemma on one side, and parallel to an equally long segment of endoplasmic reticulum on the other side. A direct continuity was found between this segment of endoplasmic reticulum and the nuclear membrane, suggesting that a form of communication may exist between the neuronal nucleus and the subsurface cistern. Occasionally the segment of endoplasmic reticulum was missing and in its place a mitochondrion appeared which seemed to be in direct contact with the pentalaminate membrane.
The origin and the course of the communicating branch of the facial nerve to the lesser petrosal nerve in man
Authors: Vidić Branislav
Published: February 2005

In order to clarify the origin and the course of the communicating branch, 25 human nerve complexes (entire intra‐osseous part of the facial nerve, greater petrosal nerve, lesser petrosal nerve, communicating branch, auricular branch of the vagus) and stapedius muscles were dissected out and removed as a whole. Each of the 25 complexes was dehydrated, sectioned serially at 10–20 μ, and either stained with Luxol Fast Blue or treated with a silver technique. The communicating branch was observed to originate from the auricular branch of the vagus. It ascended first along the anterior side of the third intra‐osseous part of the facial nerve and then penetrated the stapedius. From within the stapedius some of its fibers continued anteriorly as a nerve bundle through the facial sheath of the second intra‐osseous part of the nerve. This nerve bundle separated from the seventh nerve upon approaching the geniculate ganglion, and joined the lesser petrosal nerve. The communicating branch consisted mainly of small myelinated fibers in the course of which either isolated ganglion cells or small ganglia were sometimes present.
The double nature of the intermediate dense line in peripheral nerve myelin
Authors: Revel Jean‐Paul , Hamilton David W.
Published: February 2005

In myelin of peripheral nerves it is shown that the intermediate dense line is split after aldehyde fixation (with uranium post‐treatment) with a 20 Å gap intervening between the apposed outer leaflets of the Schwann cell membrane. This gap is permeable to colloidal lanthanum, which indicates that it is continuous with the extracellular space. Our observations are discussed in light of data of other investigators.
Myofibrillogenesis and Z‐band differentiation
Authors: Kelly Douglas E.
Published: February 2005

Developing myotubes in skeletal muscle tissue from the limbs of larval newts have been examined with respect to the ultrastructure and sequence of events accompanying myofibril formation. A population of filaments having a diameter of 100 Å is found to occur throughout and beyond the period of myofibrillogenesis. This population is in addition to developing actin and myosin filaments and probably does not contribute directly to myofibril formation. Rather it may represent a cytoskeletal network which ultimately becomes principally disposed around and at right angles to older myofibrils at the level of their Z‐bands.

Assembly of thick and thin filaments into myofibrils seems to occur, in this muscle, predominantly near the periphery of the cell with registration of these components into A‐, I‐, and Z‐bands being accomplished as they assume progressively more internal locations. Z‐bands appear to develop by coalescence of Z‐bodies which in turn are earlier related to skeins of fine filamentous material which commonly occupy the most peripheral cytoplasm of these and other mesenchymally derived cells. Fine structural details of these skeins, Z‐bodies, and Z‐bands have been analyzed with regard to the several prevailing concepts of Z‐band architecture. An hypothetical sequence for myofibril formation and Z‐band differentiation is presented which takes into account several observations and relates them to the looping filament configuration previously proposed for mature Z‐band structure.