Acupuncture meridians traditionally are believed to constitute channels connecting the surface of the body to internal organs. We hypothesize that the network of acupuncture points and meridians can be viewed as a representation of the network formed by interstitial connective tissue. This hypothesis is supported by ultrasound images showing connective tissue cleavage planes at acupuncture points in normal human subjects. To test this hypothesis, we mapped acupuncture points in serial gross anatomical sections through the human arm. We found an 80% correspondence between the sites of acupuncture points and the location of intermuscular or intramuscular connective tissue planes in postmortem tissue sections. We propose that the anatomical relationship of acupuncture points and meridians to connective tissue planes is relevant to acupuncture's mechanism of action and suggests a potentially important integrative role for interstitial connective tissue.

The Modular Resource Center (MRC) at the College of Veterinary Medicine at Cornell University was created in 1993 as a way to provide visual resources in support of a newly implemented problem-based curriculum in which the anatomical sciences are taught primarily in the first tutorial-based course, The Animal Body. Over two dozen modules have been created specifically in support of this course, whereas additional modules have been created in support of other basic science courses. The basic unit of organization of the MRC is a module presented in a carrel that provides students a way to study, either alone or in groups, a given topic. The topic is presented through a script and an integrated set of anatomical materials including plastinated dissected specimens, vascular casts, skeletal preparations, models, radiographs, histological slides, and photo- and electron micrographs. The key feature of this resource center is that it is not a museum; rather it is more analogous to an interactive library, that can be used for reference, study, and review, not only by veterinary students but also by faculty, interns, residents, and undergraduates. A unique aspect is that all materials have been made by veterinary students working with faculty during the summer. Although started as a resource in support of a tutorial-based curriculum, the MRC has evolved over a decade into an anatomy resource that would be highly valued in any curricular format.

Anatomy remains one of the core courses of medical school, but the time devoted to it is decreasing. To accommodate the explosion of medical knowledge, educators search to streamline the curriculum. Because it is time-consuming, dissection comes under increased scrutiny. Even in the face of these pressures to reduce course hours, I would like to propose broadening, not reducing, the responsibilities of the anatomy instructor. Anatomy instructors can play a crucial role in helping medical schools meet the critical need to cultivate humanistic values, especially in the arena of end-of-life care. Anatomy can--and should--play an important role in a curriculum-wide effort to address this issue. Just as dissection remains an essential technique to teach three-dimensional concepts, the cadaver dissection lab is an ideal place to introduce concepts of humanistic care. The lab evokes the students' memories, speculations, and fears about serious illness in themselves, their families, and loved ones. Some programs address these reactions with supplemental activities, such as journaling, essay writing, and small group discussion. Valuable as these activities may be, anatomy instructors can achieve more by recognizing their role as a mentor, who can integrate humanistic values into traditional course objectives in a way that adds little time to the curriculum. The attitude of the instructor in ministering to the students' needs as they undertake the emotionally charged task of dissection can provide a model for how the students will respond, in turn, to the hopes and fears of their patients-and to their own reactions to dying. This approach will allow students to implement and practice humanistic values immediately, laying a foundation for their clinical training.

Progress in paleoanthropology is impeded when new fossil materials are published but unavailable for comparative study, as is too often the case. In this commentary, we review the stages of description and analysis that new fossils must undergo and conclude that it is disingenuous to argue that fossils have not been properly "published" when descriptions and new names formulated in accordance with the International Code of Zoological Nomenclature have appeared in leading scientific journals. Once such names and descriptions have been published, it is imperative that the original fossils concerned be available to the scientific community for comparative analysis, for by the very nature of science, no statement about such fossils, however carefully prepared by the original describers (or anyone else), can be regarded as definitive. Science is a system of provisional knowledge that constantly requires re-examination and testing. It cannot function as a system in which assertions have to be left unchallenged for want of free access to the primary data.

In this study we used magnetic resonance imaging (MRI) to investigate neuroanatomical structure in the brain of a white whale (Delphinapterus leucas) that died from a large tumor within the brainstem. This specimen was also compared with a normal white whale brain using MRI. MRI scans of the white whale specimen show how the tumor deformed surrounding brain structure. Histopathological analysis indicated a poorly differentiated carcinoma of uncertain origin. These analyses demonstrate the usefulness of supplementing histological analyses of pathology with studies of gross morphology facilitated by MRI.

The elastic fiber is known to be an important component of skin, lung, and vasculature. Much less is known about the distribution of elastin and elastic fiber-related proteins in connective tissues, yet genetic defects of elastic fiber constituents can lead to deficiencies in these tissues. For the first time, we determine the distribution of elastin, fibrillins 1 and 2, and microfibril-associated glycoproteins (MAGPs) 1 and 2 in the flexor digitorum profundus (FDP) tendon. Three functionally distinct regions of the FDP tendon, the fibrocartilagenous (FC) region, avascular/tensional (AV/T) region, and insertion region, were evaluated by immunohistochemical methods for these five proteins. Biochemical analysis of desmosine content, an elastin-specific cross-link, demonstrated the presence of elastin in each region, and this was verified histochemically. The fibrillins were found with elastin and also pericellularly with internal fibroblasts where elastin was not detected. Although there was overlapping distribution, fibrillin 2 was more prominent in the interior of the tendon while fibrillin 1 was prominent in outer cell layers that contained elastic fibers. Both MAGP-1 and -2 were found throughout the tendon, although the greatest abundance was near the tendon insertion to bone. Surprisingly, MAGP-1 demonstrated a filamentous appearance within the fibrocartilage that did not correspond to the fibrillin 1 or 2 or MAGP-2 staining pattern. Lastly, we have shown that a vincular membrane located along the dorsal surface of the tendon near the insertion has a very high elastin content and a unique interface with the tendon that consists of an elastic anchor within the tendon body.

In this study, magnetic resonance (MR) images of the brain of an adult common dolphin (Delphinus delphis) were acquired in the coronal plane at 66 antero-posterior levels. From these scans a computer-generated set of resectioned virtual images in orthogonal planes was constructed using the programs VoxelView and VoxelMath (Vital Images, Inc., Michigan State Univ.). Sections in all three planes reveal major neuroanatomical structures. These structures in the adult common dolphin brain are compared with those from a fetal common dolphin brain from a previously published study as well as with MR images of adult brains of other odontocetes. This study, like previous ones, demonstrates the utility of MR imaging (MRI) for comparative neuroanatomical investigations of dolphin brains.

We characterize the urorectal septum malformation sequence (URSMS) in discordant fetal lambs and relate it to the human syndromes with which URSMS is associated. We found abnormal external genitalia, imperforate anus, and fistulous connections between the rectum, bladder, and vagina. Discordance among the dizygous twins eliminated teratogens as a likely etiologic factor. We summarize the relevant literature and propose a molecular model for the pathogenesis of the URSMS, in which alterations in sonic hedgehog and homeobox genes lead to caudal mesodermal deficiency during blastogenesis.

The detailed morphology of the renal nerves in mice has not been reported previously. The aims of this study were to describe the general morphology of the extrinsic renal nerve in C57BL/6 mice, and determine its morphometric parameters. The major renal nerve innervating the left kidney was isolated in five mice. Thin sections of the nerve segments were then examined by transmission electron microscopy. The renal nerve averaged 35.4 +/- 3.6 (S.E.M.) microm in diameter and 741 +/- 104 microm in area. The renal nerve contained an average of 830 +/- 169 unmyelinated fibers and only 4.6 +/- 1.7 myelinated fibers. The axon diameter of myelinated and unmyelinated fibers averaged 2.2 +/- 0.3 microm and 0.76 +/- 0.02 microm, respectively. The diameter of the unmyelinated fibers ranged from 0.3 to 2.0 microm, and the distribution histogram was unimodal. The majority of fibers (85%) had diameters of 0.6-1.0 microm. These results are similar to those obtained for renal nerves of rats with respect to the predominance of unmyelinated fibers. However, the diameter of unmyelinated fibers is larger in rats and the distribution histogram of rat unmyelinated fibers is bimodal, in contrast to the unimodal distribution in mice. The morphological description of the renal nerves in mice provides baseline data for further investigations of the structural basis of altered autonomic reflexes. The results will be useful in analyses of genes that influence the development and structure of sympathetic and sensory innervation of the kidney in genetically manipulated mice.

Sturgeons constitute a family of living "fossil" fish whose heart is related to that of other ancient fish and the elasmobranches. We have undertaken a systematic study of the structure of the sturgeon heart aimed at unraveling the relationship between the heart structure and the adaptive evolutionary changes. In a related paper, data were presented on the conus valves and the subendocardium. Here, the structure of the conus myocardium, the subepicardial tissue, and the conus-aorta transition were studied by conventional light, transmission, and scanning electron microscopy. In addition, actin localization by fluorescent phalloidin was used. The conus myocardium is organized into bundles whose spatial organization changes along the conus length. The variable orientation of the myocardial cell bundles may be effective in emptying the conus lumen during contraction and in preventing reflux of blood. Myocardial cell bundles are separated by loose connective tissue that contains collagen and elastin fibers, vessels, and extremely flat cells separating the cell bundles and enclosing blood vessels and collagen fibers. The ultrastructure of the myocardial cells was found to be very similar to that of other fish groups, suggesting that it is largely conservative. The subepicardium is characterized by the presence of nodular structures that contain lympho-hemopoietic (thymus-like) tissue in the young sturgeons and a large number of lymphocytes after the sturgeons reach sexual maturity. This tissue is likely implicated in the establishment and maintenance of the immune responses. The intrapericardial ventral aorta shows a middle layer of circumferentially oriented cells and internal and external layers with cells oriented longitudinally. Elastin fibers completely surround each smooth muscle cell, and the spaces between the different layers are occupied by randomly arranged collagen bundles. The intrapericardial segment of the ventral aorta is a true transitional segment whose structural characteristics are different from those of both the conus subendocardium and the rest of the ventral aorta.

We prepared decalcified sagittal sections (20 microm thick) from the incisal, middle, and basal regions of the mandibular incisor of male Wistar rats aged 2, 6, 12, and 24 months, and examined the sections using polarized light microscopy. Most of the birefringent fibers appeared to run obliquely across the periodontal ligament. Birefringent fibers running parallel to the long axis of the incisor were also found in the intermediate area of the ligament. Similar fiber architecture was observed in all four age groups. Quantitative analysis showed that the retardation values of collagen were higher in the bone- and tooth-related areas and lower in the intermediate area of the ligament. The values for the bone- and tooth-related areas increased from the basal toward the incisal regions in all four age groups. Age-related changes in the retardation values were found only in the incisal region of the incisor. In the incisal region, the values for the bone- and tooth-related areas increased markedly from 2-24 months of age, whereas those for the intermediate area increased slightly but significantly with age. Our findings indicate that the degrees of molecular organization and alignment of collagen fibers in the bone- and tooth-related areas of the ligament are higher than those in the intermediate area and increase near the incisal region and with age. It is also suggested that the collagen fibers in the intermediate area remain immature along the long axis of the incisor throughout the life span of the animal.

In order to clarify the role of antioxidant enzymes in the male rat submandibular gland against short-term normobaric oxygenation, we performed immunocytochemical staining of manganese-containing superoxide dismutase (Mn-SOD), copper- and zinc-containing SOD (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase, and glutathione S-transferases (GST alpha, GST mu, and GST pi) between days 1 and 7 after normobaric oxygenation. Ultrastructural alterations and immunoreactivities for malondialdehyde (MDA), a lipid peroxidation-related molecule, of the acinar and ductal cells after the oxygenation were also investigated. Immunoreactivity for MDA was exhibited in the acinar cells throughout the experiment. On the other hand, immunoreactivity for the SODs, CAT, and GSTs was not altered, when compared to that of controls, but was significantly elevated in the granular, striated, and excretory ductal cells. Since an increase of lipid peroxidation as indicated by enhanced immunoreactivity for MDA was detected in the acinar and intercalated ductal cells, the results indicate that the enhanced antioxidant enzymes in the granular, striated, and excretory ductal cells play a crucial role in the self-defense system of the male rat submandibular gland against normobaric oxygenation.

It is well known that the incidence of hip fractures is increasing as the population ages, and that vascularity is one of the most important characteristics for any tissue (the proximal femur being no exception). Additionally, calcified fibrocartilage from tendon and ligament insertions comprises a significant portion of the fractional area of the proximal femur's cortical shell. The goal of the present investigation was to quantify and compare the microvascularity of the cortical bone and calcified fibrocartilage of the proximal femur in a sheep model. There were no regional differences in the vascular density of the cortical bone. However, the calcified fibrocartilage from tendon and capsular insertions were determined to be avascular, and regions of the proximal femur with insertions lacked a vascularized periosteum. If a vessel was present in the calcified fibrocartilage, it was located within an isolated region of bone tissue or osteoid. Since blood vessels appear to be a significant contributor to the health and remodeling of mineralized tissue, it is hypothesized that the large areas of avascular calcified fibrocartilage present on the elderly femoral neck may predispose these regions to damage accumulation. Therefore future research should examine the role of the vascularity to the proximal femur in the mechanisms of numerous pathological conditions, such as avascular necrosis, osteopenia, and hip fractures.

Langerhans cells (LCs) are dendritic components of stratified epithelia, presenting antigens to other cells of the immune system that play a crucial role in local defense. The paucity of information about their significance in the esophageal mucosa was addressed by studying their distribution and morphology in this particular location. LCs were identified by immunohistochemical detection of CD1a, a cell-specific marker, using a monoclonal antibody, as well as by electron microscopic identification of characteristic Birbeck granules, among other typical morphological features. Cell counts carried out at 25 and 35 cm distal to the dental arch demonstrated significant differences in number and size between the two locations. The upper region contained 10.4 +/- 0.8 cells (mean +/- SEM) vs. 18.4 +/- 1.4 cells in the lower region. Also, cells in the lower region were larger and appeared to have longer dendritic processes. To our knowledge this is the first report of regional differences in number and morphology of LCs in human esophageal mucosa.

Piecemeal degranulation is a unique pattern of cell secretion that consists of a slow release of granule contents from cytoplasmic secretory granules, which leaves empty chambers that do not fuse with each other or with the plasma membrane. To our knowledge, no cell types other than mast cells, basophils, and eosinophils have been reported in the literature to show morphological features of piecemeal degranulation. In the present study we provide evidence for ultrastructural morphologies characteristic of piecemeal degranulation in entero-endocrine cells of the human and murine gastrointestinal epithelia. Human biopsy samples were taken from the mucosa of the distal duodenum, proximal jejunum, and colon in 10 patients undergoing endoscopic examination for malabsorption, diarrhea, and/or abdominal pain. Murine gastrointestinal samples were obtained from 10 adult C57 mice. All specimens were prepared for transmission electron microscopy (TEM) according to standard protocols. Results showed that different types of gastrointestinal entero-endocrine cells, in both humans and mice, were recognizable with ultrastructural features diagnostic for piecemeal degranulation, including specific granule and cytoplasmic changes. In the granules, the content was found to be loosely packed or diminished. Notably, altered granules did not fuse with each other or with the plasma membrane, and were characteristically intermingled with normal, resting granules. At times, the release events transformed the granules into enlarged, empty containers. Numerous entero-endocrine cells presented a rich supply of membrane-bound vesicles (50-200 nm in diameter) that were free in the cytoplasm or attached to granules. This finding of piecemeal degranulation in gastrointestinal entero-endocrine cells suggests that such a secretory model might be a general degranulation pattern in cells involved in paracrine-endocrine secretion.