Direct Dissection Research Articles

Caudal mesenteric plexus calves - anatomical studies.

Our study aims to elucidate some aspects concerning the vegetative inervation of calf organs situated on the terminal area of the abdominal cavi ty. Research concerning the lumbo-pelvine area were many times performed (Cavine, Habel, Patea), but data are not clear. Fifteen cadavers from 11 fetuses and 4 new - born calves were dissected, observing caudal mesenteric plexus and its connections with both lumbar sympathetic trunks, and pelvic plexus. Caudal mesenteric plexus is centered on one (40% o f cases) or many caudal mesenteric ganglions disposed in garland shape (60% of cases). The abun dance of the tissue around ganglionic mass increa ses with animals' ageing. Hipogastric nerve receives on its tract one or two splanchnic sacral nerves S1 - S2. MATERIAL AND METHOD Fifteen dissections on cadavers from 11 fetuses an d 2 new - born calves were performed. Nervous groups were observed using direct dissection, up to the limit of loop visibility. In order to facilitate the differentiat ion of vegetative groups of vascular groups acetate 10% was dispersed on dissection area.

Endoscopic submucosal dissection of early gastric cancer

The purpose of this review was to examine a remarkable technical advance regarding the indications for and the technique of endoscopic resection of early gastric cancer. Endoscopic mucosal resection (EMR) of early gastric cancer with no risk of lymph node metastasis has been a standard technique in Japan, probably owing to the high incidence of gastric cancer in Japan and the fact that more than half of Japanese gastric cancer cases are diagnosed at an early stage. Very recently, several EMR techniques have become increasingly accepted and regularly used in Western countries. Although these minimally invasive techniques are safe, convenient, and efficacious, they are unsuitable for large lesions in particular. Difficulty in correctly assessing the depth of tumor invasion and an increase in local recurrence when standard EMR procedures are used have been reported in cases of large lesions, because such lesions are often resected piecemeal owing to the technical limitations of standard EMR. A new development in therapeutic endoscopy, called endoscopic submucosal dissection (ESD), allows the direct dissection of the submucosa, and large lesions can be resected en bloc. ESD is not limited by resection size and is expected to replace surgical resection. However, it is still associated with a higher incidence of complications than standard EMR procedures and requires a high level of endoscopic skill. The endoscopic indications, techniques, and management of complications of ESD for early gastric cancer for properly carrying out established therapeutic endoscopy are described.

Multiple Forms of the 26S Proteasome‐Associated Protein Ecm29 in the Mouse Brain

AbstractEcm29 is an ˜200‐K HEAT‐repeat protein that associates with the 26S proteasome in yeast and HeLa cells. Whereas in most mouse organs Ecm29 is present as a single 200‐K protein, in the brain there are eleven species, ranging from 55 K to greater than 250 K, that react with anti‐Ecm29 antibodies. Since the largest brain‐specific Ecm29 variant reacts with antibodies to sequences within the N‐terminal and C‐terminal regions of the protein, but not to the antibody directed to its central region, this putative isoform likely arises by alternative splicing. Some of the smaller Ecm29‐positive forms appear to arise by proteolytic processing, but extraction of minced brain fragments in boiling SDS‐PAGE sample buffer reveals that all forms are present prior to homogenization. Only the 220‐K Ecm29 species is clearly associated with the 26S proteasome; with one exception, the other variants sediment slower than 20S. Direct dissection and immunohistochemistry reveal that these putative Ecm29 isoforms are present throughout the central nervous system. However, anti‐Ecm29 immunoreactivity is differentially distributed within subregions of the mouse brain and among cell types, suggesting that Ecm29 isoform distribution contributes to the complexity and regional specificity of brain function.

Surgical anatomy of the perineal muscles and their role in perineal disorders

The anterior perineum contains the perineal body and muscles. It is the site of functional and pathological disorders, many of which have not yet been related to a precise cause. In the present study, we investigated the anatomy of the perineal muscles with the aim of elucidating their function in light of their anatomic structure. Knowledge of their functional-structural relationship is deemed necessary for the understanding of the disorders that affect this part of the perineum. The perineal muscles of 28 cadaveric specimens were studied by direct dissection, as well as histologically. Fifteen male and 13 female specimens were collected from 18 adult (mean (+/- SD) age 31.6 +/- 9.8 years) and 10 neonate cadavers. Histological sections were stained with hematoxylin and eosin and Masson's trichrome stain. The fibers of the superficial transverse perineal muscle proceeded medially to decussate in a criss-cross pattern with the muscle fibers of the contralateral muscle; a few muscle fibers passed directly without decussation. Similarly, the fibers of the deep transverse perineal muscle decussated with their fellows on the opposite side. The two decussation raphes constituted the main bulk of the perineal body. A 'digastric' pattern could be identified for each of the superficial transverse perineal muscle and deep transverse perineal muscle. This pattern allows simultaneous contraction of the muscles on both sides as a single unit. The perineal muscles, forming the floor of the anterior perineum, are apparently subjected to variations in intra-abdominal pressure, which, if exceeding normal physiological limits, may lead to weakening, subluxation and sagging of the perineal muscles and, eventually, to perineocele. Further studies to investigate the role of the perineal muscles in the functional disorders of the perineum are needed.

Is the testis intraperitoneal?

The relationship of the testis to the peritoneal cavity, and hence its position as an intraperitoneal or extraperitoneal organ, remains controversial. Adult anatomy texts favour an extraperitoneal position during and after testicular descent, whereas journal articles favour an intraperitoneal position. Interestingly, there is no similar debate around the position of the ovary despite the common origin of each as indifferent gonads. Through direct observation and the literature review, we aimed to determine whether the testis should be considered an intraperitoneal or an extraperitoneal organ. The anatomical and embryological literature relevant to human and animal models was reviewed. Direct dissections were made in rats (n=8) during foetal development, postnatally, and in mature animals, allowing comparison of foetus with adult and male with female. The position of the human testis was also recorded in various pathological states. Direct dissection in rats reveals an intraperitoneal testis on a mesorchium during both foetal and postnatal life. Intraperitoneal testes are demonstrated in humans in cases of gastroschisis (where the testis may protrude through the periumbilical defect with the bowel), testicular torsion (where the testis is mobile within the peritoneum), and bell clapper testis (where the testes are identifiable as intraperitoneal). We conclude that the foetal testis is an intraperitoneal organ. In the adult rat the testis remains intraperitoneal. The postnatal human testis is intraperitoneal. The adult human testis is intraperitoneal but may appear extraperitoneal. The apparent discrepancy between the adult testis being intraperitoneal or extraperitoneal is likely to result from differences in the relative size of the tunica vaginalis between infant boys and elderly men.

Simultaneous microscopic and endoscopic monitoring during surgery for internal carotid artery aneurysms

The authors of this study evaluated the efficacy of simultaneous microscopic and endoscopic monitoring during surgery for internal carotid artery (ICA) aneurysms. The endoscopic technique was applied during microsurgery in 11 patients with 13 aneurysms. Nine of these lesions were located on the posterior communicating artery (PCoA), three in the paraclinoid region, and one on the anterior choroidal artery (AChA). Eight patients had unruptured aneurysms and three had ruptured aneurysms. The endoscope was introduced after first exposing the aneurysm through the microscope and was gripped firmly by an airlocked holding arm fitted with a steering system throughout the entire surgery, including dissection of the perforating arteries and application of the aneurysm clips. Regarding paraclinoid aneurysms, clips were applied through direct visualization of the ophthalmic artery and the proximal neck. In a case involving a superior hypophyseal artery aneurysm in the paraclinoid segment, a ring clip was applied without removing the bone structure around the optic canal. In all aneurysms of the PCoA and the AChA, perforating arteries behind the lesion were identified and dissected using endoscopic control. The aneurysm clip was applied in the best position in a single attempt in 10 of 11 patients. There was no surgical complication related to the endoscopic procedures. Simultaneous monitoring with the microscope and endoscope is extremely useful in applying clips to ICA aneurysms. This combined method allows for direct dissection of the aneurysm, perforating vessels, and the main trunk in an area not visible through the microscope's eyepiece and promises better surgical results.

The corporo-glans ligament: description and functional significance of a ligament connecting the corpora cavernosa to the glans penis.

The two corpora cavernosa (CC) end blindly under cover of the glans penis (GP). The method of attachment of the CC to the GP could not be traced in the literature. The current communication investigated the hypothesis of a ligamentous attachment existing between the two corporal ends and the GP. In all, 18 male cadaveric specimens were studied by direct dissection and histologically. Six were neonates and 12 adults (mean age 32.3+/-10.6 s.d. y). After examining and photographing the connection between the CC and GP, sagittal, parasagittal, and coronal sections of the connection were stained and studied microscopically. A triangular fibrous tissue band connected the distal blind ends of the two CC with the GP. The base of this band was attached to the tunica albuginea of the two CC, while the apex was continuous with the fibrous septa between the sinusoids of the cavernous tissue of the GP. Microscopically, the ligament consisted of collagen and elastic fibers; in some sections, the collagen fibers of the tunica albuginea were continuous with those of the band. A band of collagen and elastic fibers could be identified connecting the two CC to the GP; we term it the 'corporo-glans ligament'. This ligament presumably affords the connection with rigidity, flexibility, and tissue strength. We suggest that it firmly connects the GP to the CC during penile thrusting. Further studies are required to assess the possible role of this ligament in erectile dysfunction.

Workshop in clinical anatomy for residents in gynecology and obstetrics.

A workshop in the clinical anatomy of the female pelvic viscera has been part of the training program for the first year residents in Gynecology and Obstetrics at the University of Padova since the 1999-2000 academic year. The purpose of the workshop is to offer a direct experience of practical anatomy despite a shortage of cadavers. It is designed for six residents who work in three teams on three specimens. The anatomical specimens are unembalmed, unfixed, female pelvic visceral blocs that are harvested from the cadavers 24 hr after death. They are stored at -12 degrees C and removed from the freezer 12 hr before the workshop. The workshop is 3 hr in length and has two parts: one on theory and one practical. In the theoretical section (30 min), the teacher presents the topographical anatomy of the specimens and the residents analyze a clinically oriented worksheet. In the practical section (2 hr), the residents identify viscera, vessels, and nerves through inspection and palpation, and then a step-by-step dissection is carried out. In the last section (30 min), the workshop includes presentations on the three specimens that illustrate anatomical variability and assess knowledge of topographical anatomy. For many residents, this is the first practical experience of the anatomy of the female pelvic viscera because the anatomical courses for medical students do not include direct dissection by students. The unfixed viscera preserves the natural characteristics of the different tissues that exhibit the aspects of living organs, such as color, softness, and pliability, enhancing the knowledge of anatomy. The worksheet is structured as a guide to the anatomical basis of physical examination through inspection and palpation of the viscera. It also introduces the residents to the surgical anatomy of the female pelvis through a brief and selective dissection focused on the relationship between the different regional systems.

Accuracy of Computer Assisted Percutaneous Placement of Hiosacral Screws: A Cadaveric Study

Objective: To determine the accuracy of computer-assisted fluoronavigation for percutaneous iliosacral screw placement.Materials and Methods: A fluoronavigation system (Stryker Navigation System, Stryker Leibinger, Kalamazoo, MI) was used to guide the placement of four iliosacral screws into the S-1 bodies of each of five cadaveric pelvic specimens with intact soft tissues. Accuracy of screw placement was verified by radiographs, CT scans, and direct dissection.Results: All 20 screws were placed accurately without complications. Nineteen screws were completely contained within the osseous “safe zone.” On direct dissection, one screw was noted to have penetrated the S-1 foramina by 3 mm without impingement on the nerve root. This was not detected on radiograph or CT scan.Conclusion: The results of this study support the safety and accuracy of computer-assisted fluoronavigation for iliosacral screw placement. The advantages include decreased fluoroscopic time, real-time simultaneous visualization of all three views (inlet, outlet, and lateral), and increased accuracy of placement. Clinical study is warranted.

The Earthworm Lumbricus terrestris as a Possible Paratenic or Intermediate Host of the Pig Parasite Ascaris suum

Published reports suggest that some species of earthworms may serve as paratenic hosts or even intermediate hosts for the pig parasite, Ascaris suum. This study was conducted to determine whether infective As. suum eggs could hatch and the larvae remain infective within the earthworm, Lumbricus terrestris. Pig feces containing infective As. suum eggs were fed to earthworms that were then allowed to purge their intestines and eliminate ascarid eggs. Although exposed earthworms were examined using direct dissection, agar, and digestion techniques, no As. suum larva was recovered from the earthworms. Twenty-five exposed earthworms were administered to each of 3 helminth-free pigs, but no As. suum larva was isolated from the liver, the lungs, or the small intestine on days 4, 7, and 11 postinoculation. No intermediate or paratenic host role for L. terrestris in the As. suum life cycle was demonstrated. Unexpectedly, unidentified nematode larvae were isolated from both the earthworms and the lungs of the earthworm-fed pigs. These earthworms were imported from Canada and were usually sold to anglers for fish bait, suggesting that the human-mediated transport of intermediate or paratenic hosts may introduce parasites to new geographic regions.

The histomorphologic structure of the levator ani muscle and its functional significance.

The levator ani muscle (LAM), unlike other striated muscles has resting myoelectric activity, the cause of which is not precisely known. In a recent study this activity was suggested to be related to the presence of smooth muscle bundles in the LAM. The present study investigated this point in 25 cadaveric specimens (10 neonates, 15 adults). Histologic examination of the LAM was performed in 12 specimens, three to six slices being taken from the lateral to the medial side of each muscle, processed and stained with H&E and Masson's trichrome stain. The remaining 13 specimens were studied by direct dissection and photographed. Microscopic examination of specimens from adult cadavers showed that the lateral part of the LAM consisted of purely skeletal muscle bundles, mostly of the small-caliber type and few of the large or intermediate type. As we proceeded medially, smooth muscle bundles started to appear. Examination of slices medial to the midportion of the LAM showed that the muscle began to be separated into two layers: a deep (pelvic) one formed of smooth fibers and a superficial (perineal) one of skeletal fibers, separated by a neurovascular plane. Microscopic examination of specimens from neonates showed that the whole LAM consisted of skeletal fibers; no smooth fibers or separation into two layers were identified. By direct dissection of the adult specimens the medial part of the LAM consisted of two layers, superficial and deep, which were separated by fascia containing vessels and nerves. The muscle was thicker at its medial part and tapered laterally, with loss of demarcation, into two layers. Specimens from neonates showed no differentiation of the LAM, into two layers. It is suggested that the deep layer of the LAM, which was formed of smooth fibers, acts involuntarily, supporting the pelvic viscera by its tone and responding to variations in intra-abdominal pressure by adaptation of this tone. The superficial layer of the LAM, made of skeletal fibers, appears to represent the functional mobile part that acts voluntarily during urination or defecation. The presence of the smooth fibers in the adult LAM and not in neonates seems to be adaptational, caused by the action of intra.abdominal pressure and visceral weight. The skeletal fibers pass into various histologic stages before they transform to smooth fibers.

Determining the volume of hip cartilage by magnetic resonance imaging

Objective: Little progress has been made in developing a non-invasive method for assessing hip cartilage in vivo. The aim of our study was to determine whether the volume of hip cartilage can be determined accurately and reproducibly from routinely performed magnetic resonance images (MRI).Methods: Ten femoral heads obtained at surgery (five men, five women; aged 67–75 years) were used to compare cartilage volume estimates obtained using MRI with direct dissection of cartilage from anatomical samples. Hip MRI from six randomly selected patients having MRI for clinical indications were used to assess the reproducibility of MRI cartilage volume. Articulate cartilage volumes were determined by means of three-dimensional image processing of TI-weighted fat saturated, sagittal MRI.Results: The volume of the cartilage from the 10 hip specimens ranged from 1.8 to 7.8ml, as determined by the MRI method, and 1.6 to 8.1ml, as determined by dissection and volume displacement. The average over- and under-estimation of the cartilage volume using MRI was 0.6 (12%)±0.6ml. The coefficient of variation, as a measure of reproducibility, was 6.6%, based on six subjects, measured five times.Conclusions: The volume of femoral head cartilage can be measured non-invasively with good accuracy and reproducibly from standard diagnostic MRI. As cartilage volume measures are not subject to the same difficulty in reselecting identical section locations in follow-up MRI as other methods examining structural changes in the hip joint, this method may be useful in longitudinal studies examining therapeutic agents and preventive strategies in hip arthritis.

Computer-assisted resection of cerebral arteriovenous malformations.

A series of 22 patients with arteriovenous malformations (AVMs) were surgically treated using computer-assisted image guidance. The value of image guidance for nidus definition and detection of feeding arteries and draining veins was assessed. Seven of the 22 patients presented with hemorrhage. The sizes of the AVMs ranged from 1 to 8 cm. Six patients underwent preoperative embolization. For 18 patients (81.8%), the AVMs were located in highly eloquent areas. A passive-marker-based neuronavigation system (BrainLab, Heimstetten, Germany) was used for intraoperative image guidance. Segmentation of the pathological vessels was performed preoperatively, on the basis of 2-mm helical computed tomographic angiographic slices, to obtain three-dimensional reconstructions of the AVMs. Temporary clips were initially placed on all identifiable feeding arteries, for intranidal pressure reduction before AVM dissection. Dissection of the AVMs was then performed along the main draining veins, as identified by neuronavigation. Patient follow-up monitoring ranged from 3 to 16 months (median, 7 mo). The computer-calculated registration accuracy ranged between 1.1 and 3.1 mm (median, 1.4 mm). Exact nidus definition was possible for all 22 patients. The principal draining veins were also identified for all patients. Feeding arteries could be detected after the segmentation process when the vessels were at least 3 mm in diameter (19 patients). Complete collapse of the AVMs was achieved with initial clip application for 3 patients; partial intranidal pressure reduction was observed for 12 patients. No significant decompression by feeder clipping was possible for pre-embolized AVMs. Perioperative mortality and morbidity rates were 0 and 14%, respectively. This image-guided technology allows observation of the relationship between AVMs and adjacent brain structures, increasing spatial orientation during surgery. Definition of an optimal surgical approach and early localization of feeding arteries for temporary occlusion minimize tissue manipulation and enhance the safety of direct dissection along the draining veins, which is necessary in eloquent areas.

Study of the arterial pattern of the rectum and its clinical application.

The purpose of this communication was to study rectal arterial supply in order to characterize its various patterns and use them to help avoid rectal ischemic complications and, in addition, to explain some of the unknown rectal pathologic conditions. Thirty-two cadavers were studied. The pelvic organs were eviscerated. The rectal arteries were examined by direct dissection in 12 specimens and after injecting the inferior mesenteric artery with barium sulfate in 20 specimens. The superior rectal artery (SRA) and vein were found to be enclosed in a fibrous sheath which was connected to the posterior rectal surface by an anterior mesorectum containing the "transverse rectal branches', and to the sacrum by an avascular posterior mesorectum. Small lymph nodes were scattered alongside the anterior mesorectum. The SRA gave rise to 4 branches: transverse rectal, descending rectal, rectosigmoid and terminal. The transverse rectal arteries arose from the SRA in 24 specimens and from the descending rectal artery in 8. They were distributed to the upper half of the rectum. The rectosigmoid artery was distributed to the descending limb of the sigmoid colon and rectosigmoid junction. We found 2 terminal branches in 21/32 cadavers and 3 in 11/32. They communicated in the lower half of the rectum. The inferior rectal arteries were present in all the dissected cadavers while the middle rectal arteries could be identified in only 50% of the cadavers. Two arterial patterns were recognized: annular in the upper rectal half provided by the transverse rectal arteries and plexiform in the lower half supplied by the SRA terminal branches.

Direct microdissection and microcloning of a translocation breakpoint region, t(1;11)(q42.2;q21), associated with schizophrenia.

We describe the generation of large-fragment microclone libraries from the chromosomal breakpoint of a reciprocal balanced translocation linked to schizophrenia. The abnormality was visible under the phase-contrast microscope, allowing direct dissection from unstained, unbanded metaphases. Two separate microdissection experiments yielded 443 and 672 recombinants, respectively. Following complete EcoRI digestion, inserts with an average size of 0.3 kb (range, 0.2-3 kb) were obtained in the first experiment and 1.5 kb (range, 0.15-6.5 kb) in the second. FISH analysis of pooled clones "painted" back onto the derivative chromosome and assignment of microclones to somatic cell hybrids confirmed the fidelity of the method. Microdissection of chromosome regions identified by karyotype rearrangements in unstained, unbanded metaphases is a potentially powerful tool for positional cloning.

Meningeal arteries in rhesus macaques (Macaca mulatta): implications for vascular evolution in anthropoids.

The branching patterns of meningeal arteries are reported for 200 endocast hemispheres representing rhesus monkeys (Macaca mulatta) of known cranial capacity. We detect five basic patterns for the branching of the anterior division of the middle meningeal artery and its relationship with the anterior meningeal artery. These results confirm and elaborate trends published for much smaller samples that were based on direct dissections of rhesus monkey arterial patterns. The most common pattern is that in which the anterior meningeal artery dominates the blood supply above the rostral part of the middle cranial fossa. Analysis of cranial capacities reveals that presence of this pattern on both sides of endocasts is associated with increased cranial capacity. When studied in light of published reports of anatomical dissections of cranial arteries in apes and human embryological data, the anterior meningeal artery in rhesus monkeys appears to be a possible homologue of the lacrimal meningeal artery in apes and the anterior branch of the middle meningeal artery in humans. This finding provides a step towards understanding cranial vasculature homologies that may be useful for accurately scoring the branching patterns of the meningeal arteries in monkeys, apes, and humans.

What is the optimal depth for core-out toward the foramen cecum in a thyroglossal duct cyst operation?

The high recurrence rate of thyroglossal duct cyst operations is well documented. Sistrunk's operation is widely accepted as the best procedure to prevent recurrence. Nonetheless, the optimum depth of core-out is still not well documented. We previously reported a standard running pattern of the thyroglossal duct in an anatomical reconstruction study. In more detailed pathological studies, we have tried to determine the optimal depth for core-out toward foramen cecum and the optimal width of the hyoid bone to be resected. The following items were clarified. (1) Double the horizontal distance from midline to the most distant thyroglossal duct in front of the hyoid bone was 2.4 to 9.6 mm. (2) The length of the single duct above the hyoid bone which spreads into many ductuli as it approaches the foramen cecum was about 3 to 5 mm in 2- to 6-year old children. (3) The diameter of the thyroglossal duct at the level of the cranial top of the hyoid bone was 175 to 1,400 microns. Half of the examined cases were less than 500 microns, which may have rendered direct dissection impossible. Based on these studies, we propose: (1) that a minimum of 10 mm of the hyoid bone should be resected, and for the sake of safety, more than 15 mm is preferable; and (2) that the depth of the core-out should be less than 5 mm in young children to avoid the breakdown of the branched ductuli near the foramen cecum.

Dilatation in anastomosed arteries can be an artifact of explantation.

Fusiform dilation of the anastomotic site was found at explantation in the majority of rabbit femoral arteries anastomosed with newly developed microclips. This observation was also noted at sutured anastomoses. The mechanism responsible for this morphologic finding was studied by the following experiments: 1) measuring and explanting anastomosed arteries relaxed with 20% lidocaine, 2) latex casts of microclipped arteries, 3) comparing angiographic and histologic morphometric data, and 4) examining synthetic vascular graft anastomoses with identical dilatation. The observations demonstrate that trauma associated with explantation (direct dissection and fixative perfusion) leads to arterial vasoconstriction, but focal medial damage at the anastomotic site prevents constriction at this site.

A CASE OF CHRONIC PANCREATITIS INVOLVING THE SPLEEN

A case of chronic pancreatitis involving the spleen is reported.A 55-year-old man was admitted to the hospital with the chief complaint of left back pain. Laboratory data revealed high amylase level in the serum and urine. Abdominal ultrasono graphy and computed tomography demonstrated multiple calcification and cysts in the tail of the pancreas and a cystic lesion in the spleen. In the cystic fluid of the spleen, the amylase level was much higher than the serum level. The patient was diagnosed as having pancreatic pseudocyst involving the spleen.Splenectomy and distal pancreatectomy were performed. There was no connection between the splenic cyst and the pancreas. Pathologically, the cyst in the spleen had no epithelial lining on its wall and was proven to be an intrasplenic pseudocyst. We suggest, as a possible mechanism for the formation of the intrasplenic cyst, a direct dissection of the splenic parenchyma by panreatic enzymes released from the pancreas.

Direct experimental dissection of devitrification in aqueous solutions of 1,3-butanediol

Direct experimental dissection of devitrification in aqueous solutions of 1,3-butanediol