Injectate spread in ultrasound-guided inferior alveolar nerve block: a cadaveric study.

PURPOSE: Ultrasound-guided inferior alveolar nerve block (UGIANB) is a mandibular analgesic procedure in which local anesthetic is injected into the pterygomandibular space (PMS). Several studies have reported the clinical efficacy of UGIANB for mandibular surgeries; however, its effective range has never been investigated. We performed a cadaveric study to investigate the success rate of UGIANB injections and to determine whether injected dye could stain the mandibular nerve (MN) trunk and its branches. METHODS: We performed UGIANB on the bilateral faces of 4 Thiel-embalmed cadavers. A needle was advanced to the PMS under ultrasound guidance and 5 mL of dye was injected. The cadaver was dissected and inspected for the presence of dye in the PMS; the range of dye spread to any of the inferior alveolar nerve (IAN), lingual nerve (LN), buccal nerve (BN), mandibular nerve (MN), auriculotemporal nerve (ATN), or facial nerves; and for the presence of intravascular dye. RESULTS: We performed eight UGIANB procedures on four cadavers. Dye was observed in the PMS in 7/8 injections. Staining was observed in all IAN, LN, and BNs that could be identified at dissection. No MN or auriculotemporal nerves (ATNs) were stained in any injections. No intravascular dye was observed in any injections. CONCLUSIONS: UGIANB can administer anesthetic into the PMS with high accuracy. UGIANB injections reached the IAN, LN, and BNs, but did not reach the MN or ATNs located outside the PMS. The findings of this cadaveric study indicate that UGIANB can provide sufficient analgesia for mandibular surgeries.

Morphological characteristics of the lateral ankle ligament complex.

PURPOSE: The relevance of each ligament comprising the lateral ankle ligament complex, including the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL), has not been sufficiently elucidated; therefore, we aimed to clarify the morphological characteristics and relevance of these ligaments. METHODS: Total 152 legs from 152 Japanese cadavers were investigated. The lengths and widths of the ATFL, CFL, and PTFL were measured using a caliper. The ATFL was classified according to the number of fiber bundles (Types I, II, and III corresponded to one, two, and three fiber bundles, respectively), and the lengths and widths of the three ligaments were compared between the Type groups. In addition, the ratio of each ligament's length and width to the tibial length was calculated, and the correlation of the ratio of ligament length and width between the ATFL, CFL, and PTFL was examined about 34 legs. RESULTS: The ATFL, CFL, and PTFL were found to connect at the anterior/inferior tip of the lateral malleolus each other. The Type II group of the ATFL was most common (54.6%) in our investigated specimens. However, there were no significant inter-group differences in the lengths and widths of the CFL and PTFL. CONCLUSIONS: This study demonstrates that the lateral ankle ligaments may stabilize the ankle joint through interconnections.

Biomechanical Analysis of Midfoot Instability After Bifurcate Ligament Injury and Ankle Brace Application: A Cadaveric Study.

This cadaveric study investigated the biomechanical characteristics and stabilizing contribution of the bifurcate ligament using a multidirectional loading method and assessed the stabilizing effect of a brace after injury of the ligament. Eight freshly frozen cadaveric feet were tested for forefoot torque in inversion, eversion, adduction, and plantarflexion. Each band of the bifurcate ligament was transected sequentially, and the contribution of each portion of the ligament, as well as the stabilizing effects of the ankle brace, were examined. Stability decreased substantially after calcaneocuboid ligament transection for inversion and adduction loading. Bracing restored some stability, except for the adduction loading direction, for which it had only limited effect. The data indicate that inversion and adduction loading are strongly related to bifurcate ligament injury. The stabilizing effect of the ankle brace may have limited effectiveness for loads under adduction.

A Biomechanical Comparison of Single-, Double-, and Triple-Bundle Anterior Cruciate Ligament Reconstructions Using a Hamstring Tendon Graft.

PURPOSE: The first objective of our cadaveric study was to perform a biomechanical comparison of single-bundle (SB), double-bundle (DB), and triple-bundle (TB) anterior cruciate ligament (ACL) reconstructions using a hamstring tendon graft to determine the laxity match pre-tension (LMP) value, which is the tension within the graft required to re-create the same anterior laxity as the ACL-intact knee. The second objective was to determine the anterior laxity and force distribution during the application of both an anterior force and a simulated pivot-shift test. METHODS: Eleven fresh-frozen cadaveric knees were tested using a robotic/universal force-moment sensor system in the intact state, TB-reconstructed knee, DB-reconstructed knee, and SB-reconstructed knee. The LMP in each reconstruction was recorded. Each reconstructed knee was tested with an external load of 100-N anterior drawer and combined rotatory loads of 10-Nm valgus moment and 5-Nm internal rotation. The anterior tibial translation and tensile forces of each graft bundle were measured. RESULTS: The LMP values for the TB reconstruction were 1.7 N for the anteromedial-medial graft, 1.7 N for the anteromedial-lateral graft, and 3.4 N for the posterolateral graft (PLG). The LMP value was 5.6 N for the anteromedial graft and PLG in the DB reconstruction. The LMP value was 26.3 N for the whole graft in the SB reconstruction. No statistically significant difference in stability was found between TB and DB reconstructions during the anterior load and the combined rotatory load test. For force distribution, the PLG tension in the TB reconstruction was statistically lower than that in the DB reconstruction. CONCLUSIONS: Anatomic TB ACL reconstruction with the lowest initial tension on the graft stabilized the knee equally to DB or SB reconstruction, which required greater initial tension. CLINICAL RELEVANCE: Although SB, DB, and TB ACL reconstructions through the anatomic tunnel position could equally restore stability, the initial tension on the graft required to restore stability was less in the latter 2 multi-tunnel reconstructions.

Osteopontin attenuates acute gastrointestinal graft-versus-host disease by preventing apoptosis of intestinal epithelial cells.

BACKGROUND AND AIMS: Acute graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation, which often targets gastrointestinal (GI) tract. Osteopontin (OPN) plays an important physiological role in the efficient development of Th1 immune responses and cell survival by inhibiting apoptosis. The role of OPN in acute GI-GVHD is poorly understood. In the present study, we investigated the role of OPN in donor T cells in the pathogenicity of acute GI-GVHD. METHODS: OPN knockout (KO) mice and C57BL/6 (B6) mice were used as donors, and (C57BL/6 × DBA/2) F1 (BDF1) mice were used as allograft recipients. Mice with acute GI-GVHD were divided into three groups: the control group (BDF1→BDF1), B6 group (B6→BDF1), and OPN-KO group (OPN-KO→BDF1). Bone marrow cells and spleen cells from donors were transplanted to lethally irradiated recipients. Clinical GVHD scores were assessed daily. Recipients were euthanized on day 7 after transplantation, and colons and small intestines were collected for various analyses. RESULTS: The clinical GVHD score in the OPN-KO group was significantly increased compared with the B6 and control groups. We observed a difference in the severity of colonic GVHD between the OPN-KO group and B6 group, but not small intestinal-GVHD between these groups. Interferon-γ, Tumor necrosis factor-α, Interleukin-17A, and Interleukin-18 gene expression in the OPN-KO group was differed between the colon and small intestine. Flow cytometric analysis revealed that the fluorescence intensity of splenic and colonic CD8 T cells expressing Fas Ligand was increased in the OPN-KO group compared with the B6 group. CONCLUSION: We demonstrated that the importance of OPN in T cells in the onset of acute GI-GVHD involves regulating apoptosis of the intestinal cell via the Fas-Fas Ligand pathway.

Establishment of a refined culture method for rat colon organoids.

BACKGROUND: Methods for the artificial three-dimensional (3D) culture of mouse and human small-intestinal and large-intestinal stem cells have been established with CD24+ or Paneth cell niches. In contrast, no studies have established stable 3D culture for rat colon stem cells. In this study, we established an advanced method for efficient rat colonic stem cell culture. METHODS: Using various tissue homogenates, we investigated the colonic organoid forming capacity under the TMDU protocol immediately adjacent to Ootani's 3D culture assembly in the same culture dish. Next, we examined whether the supernatant from the colon could be replaced by a colon homogenate. Finally, we identified the bioactive substances that were indispensable for efficient organoid culture using protein purification by three-step column chromatography and proteomic analysis with a quantitative nanoflow liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: By combining Ootani's method with the TMDU protocol, we established a refined culture method for Lewis rat colon organoids, which we refer to as the modified TMDU protocol. Furthermore, we confirmed that PGE2 and galection-4 promoted rat colonic organoid formation. CONCLUSIONS: We established efficient rat colonic stem cell cultures in vitro. This success will contribute to the study of rat intestinal-disease models.

The anterolateral ligament in a Japanese population: Study on prevalence and morphology.

BACKGROUND: The anterolateral ligament of the knee (ALL) has been attracting research attention as the ligament related to the Segond fracture. In this study, we investigated the prevalence and morphological variation of the ALL and developed a classification for the ALL in Japanese people. METHODS: A total of 94 knees of 54 room cadavers of Japanese people were examined (24 male, 30 female; age range 70-103 years; average age: 85.6 years). Knees with damaged ligaments, such as ACL rupture, and with bony abnormalities were excluded. The ALL-like structure was classified based on orientation and shape of the structures. RESULTS: The fibrous structure independent from the knee joint capsule in the anterolateral part of the knee was present in 35 knees out of 94 knees (37.2%). This structure was classified into two types, based on thickness: type I is for the strong ligamentous structures of more than 1 mm in thickness; and type II is for weak aponeurotic structures of equal or less than 1 mm thickness. Here we regard the anterolateral ligament (ALL) as the type I and the type II is termed anterolateral ligamentous tissue (ALLT). Type I was seen in 19 of 35 knees (54.3%), and type II was seen in 16 of 35 knees (45.7%). CONCLUSIONS: This study described the fibrous structure of the anterolateral portion of the knee, and classified the ligamentous structure into type I (ALL) and thin aponeurotic type II (ALLT). The prevalence of the ALL in Japanese people was approximately 20% and was significantly lower than in previous studies, which were reported values from 50% to 100%.

Mesenchymal stem cell therapy ameliorates diabetic hepatocyte damage in mice by inhibiting infiltration of bone marrow-derived cells.

UNLABELLED: Although mesenchymal stem cells (MSCs) have been implicated in hepatic injury, the mechanism through which they contribute to diabetic liver disease has not been clarified. In this study, we investigated the effects of MSC therapy on diabetic liver damage with a focus on the role of bone-marrow-derived cells (BMDCs), which infiltrate the liver, and elucidated the mechanism mediating this process. Rat bone-marrow (BM)-derived MSCs were administered to high-fat diet (HFD)-induced type 2 diabetic mice and streptozotocin (STZ)-induced insulin-deficient diabetic mice. MSC-conditioned medium (MSC-CM) was also administered to examine the trophic effects of MSCs on liver damage. Therapeutic effects of MSCs were analyzed by assessing serum liver enzyme levels and histological findings. Kinetic and molecular profiles of BMDCs in the liver were evaluated using BM-chimeric mice. Curative effects of MSC and MSC-CM therapies were similar because both ameliorated the aggravation of aspartate aminotransferase and alanine aminotransferase at 8 weeks of treatment, despite persistent hyperlipidemia and hyperinsulinemia in HFD-diabetic mice and persistent hyperglycemia in STZ-diabetic mice. Furthermore, both therapies suppressed the abnormal infiltration of BMDCs into the liver, reversed excessive expression of proinflammatory cytokines in parenchymal cells, and regulated proliferation and survival signaling in the liver in both HFD- and STZ-diabetic mice. In addition to inducing hepatocyte regeneration in STZ-diabetic mice, both therapies also prevented excessive lipid accumulation and apoptosis of hepatocytes and reversed insulin resistance (IR) in HFD-diabetic mice. CONCLUSION: MSC therapy is a powerful tool for repairing diabetic hepatocyte damage by inhibiting inflammatory reactions induced by BMDCs and IR. These effects are likely the result of humoral factors derived from MSCs.

Mesenchymal stem cells cancel azoxymethane-induced tumor initiation.

The role of mesenchymal stem cells (MSCs) in tumorigenesis remains controversial. Therefore, our goal was to determine whether exogenous MSCs possess intrinsic antineoplastic or proneoplastic properties in azoxymethane (AOM)-induced carcinogenesis. Three in vivo models were studied: an AOM/dextran sulfate sodium colitis-associated carcinoma model, an aberrant crypt foci model, and a model to assess the acute apoptotic response of a genotoxic carcinogen (AARGC). We also performed in vitro coculture experiments. As a result, we found that MSCs partially canceled AOM-induced tumor initiation but not tumor promotion. Moreover, MSCs inhibited the AARGC in colonic epithelial cells because of the removal of O(6)-methylguanine (O(6) MeG) adducts through O(6) MeG-DNA methyltransferase activation. Furthermore, MSCs broadly affected the cell-cycle machinery, potentially leading to G1 arrest in vivo. Coculture of IEC-6 rat intestinal cells with MSCs not only arrested the cell cycle at the G1 phase, but also induced apoptosis. The anti-carcinogenetic properties of MSCs in vitro required transforming growth factor (TGF)-ß signaling because such properties were completely abrogated by absorption of TGF-ß under indirect coculture conditions. MSCs inhibited AOM-induced tumor initiation by preventing the initiating cells from sustaining DNA insults and subsequently inducing G1 arrest in the initiated cells that escaped from the AARGC. Furthermore, tumor initiation perturbed by MSCs might potentially dysregulate WNT and TGF-ß-Smad signaling pathways in subsequent tumorigenesis. Obtaining a better understanding of MSC functions in colon carcinogenesis is essential before commencing the broader clinical application of promising MSC-based therapies for cancer-prone patients with inflammatory bowel disease.

Effect of simultaneous stretching of the wrist and finger extensors for lateral epicondylitis: a gross anatomical study of the tendinous origins of the extensor carpi radialis brevis and extensor digitorum communis.

BACKGROUND: Pulling the wrist into flexion with the elbow in extension and forearm in pronation has been used as the stretching technique of wrist extensors for lateral epicondylitis. Simultaneous stretching of the fingers in addition to the wrist flexion has also been applied. However, the mechanism of this simultaneous stretching has not been clarified. This study is designed to clarify the mechanism underlying this simultaneous stretching technique based on the anatomical features of the origins of the extensor carpi radialis brevis (ECRB) and extensor digitorum communis (EDC). METHODS: Thirty-nine arms from formalin-embalmed Japanese human specimens were dissected. The features of the origins of the ECRB and EDC were macroscopically observed, and the locations of each origin on the lateral epicondyle were measured. RESULTS: The ECRB had a long and wide, purely tendinous origin which originated from the anterior slope of the lateral epicondyle. The tendinous origin of the index finger of the EDC (EDC-IF) arose from the posterior aspect of the ECRB tendinous origin, with a coexisting muscular portion observed at the level of the proximal forearm. The middle finger of the EDC (EDC-MF) had a short tendinous origin with an associated muscular portion and originated proximo-laterally to the origin of the ECRB on the lateral epicondyle. In addition, the muscular origin of the EDC-MF arose on the superficial and posterior aspect of the ECRB tendinous origin. In contrast, the ring and little fingers of the EDC originated from the tendinous septum of the extensor digiti minimi and extensor carpi ulnaris, and had no connection with the ECRB tendinous origin. CONCLUSIONS: On the basis of our anatomical findings, simultaneous stretching of the wrist extensors by wrist, index and middle fingers flexion could provide stretching force to both the tendinous origins of the ECRB and EDC through the EDC-IF and EDC-MF.

Pressure and tendon strain in the sixth extensor compartment of the wrist during simulated provocative maneuvers for diagnosing extensor carpi ulnaris tendinitis.

BACKGROUND: Various provocative maneuvers for diagnosing extensor carpi ulnaris (ECU) tendinitis have been reported; however, it remains unclear which maneuver is the most sensitive to detect ECU tendinitis. To clarify this, we investigated and compared the extratendinous pressure and ECU tendon strain in the sixth extensor compartment of the wrist during various provocative maneuvers for diagnosing ECU tendinitis. METHODS: Nine upper extremities from nine fresh-frozen cadavers were examined. We investigated extratendinous pressure in the ECU fibro-osseous tunnel of the distal ulna and ECU tendon strain during eight forearm positions-neutral rotation, pronation, supination, pronation with wrist flexion, supination with wrist flexion, supination with wrist extension, both hand and forearm supination, and supination with ECU full loading-to simulate provocative maneuvers reported to detect ECU tendinitis. RESULTS: Pressure was significantly higher during both hand and forearm supination (carpal supination test) and during supination with wrist extension (prayer's hand supination test) than during neutral rotation. The pressure during the carpal supination test was 3 times higher than that during the prayer's hand supination test and 27 times higher than that during the neutral position. Strain was significantly higher during the carpal supination test and during supination with ECU full loading (the ECU synergy test) than during other maneuvers. CONCLUSIONS: Both pressure and tendon strain increased most notably during the carpal supination test compared to the other maneuvers, which suggests that the carpal supination test is the most sensitive for the detection of ECU tendinitis.

Nerve supply to the internal anal sphincter differs from that to the distal rectum: an immunohistochemical study of cadavers.

PURPOSE: Fecal incontinence is a common problem after anal sphincter-preserving operations. The intersphincteric autonomic nerves supplying the internal anal sphincter (IAS) are formed by the union of: (1) nerve fibers from Auerbach's nerve plexus of the most distal part of the rectum and (2) the inferior rectal branches of the pelvic plexus (IRB-PX) running along the conjoint longitudinal muscle coat. The aim of the present study is to identify the detailed morphology of nerves to the IAS. METHODS: The study comprised histological and immunohistochemical evaluations of paraffin-embedded sections from a large block of anal canal from the preserved 10 cadavers. RESULTS: The IRB-PX came from the superior aspect of the levator ani and ran into the anal canal on the anterolateral side. These nerves contained both sympathetic and parasympathetic fibers, but the sympathetic content was much higher than in nerves from the distal rectum. All intramural ganglion cells in the distal rectum were neuronal nitric oxide synthase-positive and tyrosine hydroxylase-negative and were restricted to above the squamous-columnar epithelial junction. Parasympathetic nerves formed a lattice-like plexus in the circular smooth muscles of the distal rectum, whereas the IAS contained short, longitudinally running sympathetic and parasympathetic nerves, although sympathetic nerves were dominant. CONCLUSIONS: The major autonomic nerve input to the IAS seemed not to originate from the distal rectum but from the IRB-PX. Injury to the IRB-PX during surgery seemed to result in loss of innervation to the major part of the IAS.

Biomechanical comparison between the rectangular-tunnel and the round-tunnel anterior cruciate ligament reconstruction procedures with a bone-patellar tendon-bone graft.

PURPOSE: The purpose of this study was to evaluate the effectiveness of 2 anterior cruciate ligament (ACL) reconstruction techniques using a bone-patellar tendon-bone (BPTB) graft with femoral tunnel, either a rectangular tunnel (RET) or a round tunnel (ROT). METHODS: For experiment 1, nine fresh-frozen human cadaveric knees were tested with a robotic/universal force-moment sensor system to determine the initial optimal tension: the amount of graft tension at 15° of flexion most closely resembling the anterior laxity of a normal knee. The value was estimated by repeatedly measuring anterior laxity when 100 N of anteroposterior drawer load was applied to the knees at 30° of flexion after RET ACL or ROT ACL reconstruction. For experiment 2, six fresh-frozen human cadaveric knees were selected. On the basis of the initial tension determined in experiment 1, RET ACL reconstruction was conducted with the graft tensioned to 10 N, followed by ROT ACL reconstruction on the same knee at 40 N of initial tension, and the biomechanical efficacy of the 2 methods was compared. RESULTS: For experiment 1, the mean laxity match tension at 15° of flexion was 8.6 ± 4.8 N and 34.8 ± 9.2 N for RET- and ROT-reconstructed knees, respectively. For experiment 2, both RET and ROT ACL reconstructions were successful in controlling anterior tibial translation under anterior tibial loads, with the graft initially tensioned to 10 N in the former and to 40 N in the latter. However, the greater tensioning in ROT reconstruction led to proximal, posterior, and lateral displacement of the tibia along with its external and valgus rotation. CONCLUSIONS: The RET ACL-reconstructed knee more closely resembled the normal knee in biomechanical behavior. Although ROT reconstruction successfully controlled anterior translation with greater initial tensioning to the graft, the normal positional relation between the tibia and femur was impaired. CLINICAL RELEVANCE: Rectangular femoral ACL fixation constructs and grafts may prove more efficacious at restoring in vivo ACL kinematics than round femoral tunnels.

The adductor part of the adductor magnus is innervated by both obturator and sciatic nerves.

The hip adductor group, innervated predominantly by the obturator nerve, occupies a large volume of the lower limb. However, case reports of patients with obturator nerve palsy or denervation have described no more than minimal gait disturbance. Those facts are surprising, given the architectural characteristics of the hip adductors. Our aim was to investigate which regions of the adductor magnus are innervated by the obturator nerve and by which sciatic nerve and to consider the clinical implications. Twenty-one lower limbs were examined from 21 formalin-fixed cadavers, 18 males and 3 females. The adductor magnus was dissected and was divided into four parts (AM1-AM4) based on the locations of the perforating arteries and the adductor hiatus. AM1 was supplied solely by the obturator nerve. AM2, AM3, and AM4 received innervation from both the posterior branch of the obturator nerve and the tibial nerve portion of the sciatic nerve in 2 (9.5%), 20 (95.2%), and 6 (28.6%) of the cadavers, respectively. The double innervation in more than 90% of the AM3s is especially noteworthy. Generally, AM1-AM3 corresponds to the adductor part, traditionally characterized as innervated by the obturator nerve, and AM4 corresponds to the hamstrings part, innervated by the sciatic nerve. Here, we showed that the sciatic nerve supplies not only the hamstrings part but also the adductor part. These two nerves spread more widely than has generally been believed, which could have practical implications for the assessment and treatment of motor disability.

Macroscopic and microscopic features of the mandibular condyle in autopsied elderly individuals.

Many studies have attempted to classify the macroscopic shapes of the mandibular condyle in humans; however, no consensus has yet been reached because the shapes vary. One problem is that classification of macroscopic morphological changes of the condylar surface has been largely based on bones from ancient people, with few bones from modern people covering many different age groups. In this study, 144 condyles from 78 cadavers (40 men, 38 women; age at death: >70 years) were investigated. The macroscopic shapes of the condyles were classified from posterior and lateral views into four types: convex, flattened, angled, and irregular. Of the 144 condyles, 25 were investigated microscopically. On macroscopic examination, in both posterior and lateral views, convex-type condyles were most frequently observed. Most posterior convex-type condyles were also categorized as the lateral convex type. On histological examination, we observed an increase in cartilage cells (7 condyles, 28%), a decrease in cartilage cells (3 condyles, 12%). Increases in cartilage cells were seen only in angled and irregular types (P = 0.001), whereas decreases in cartilage cells were only observed in the flattened type (P = 0.01). A convex macroscopic form appears to be standard for human mandibular condyles, even in the elderly. The histological findings suggest that mandibular condyles tend to not only undergo flattening, but also undergo progressive changes toward protrusion with age due to increased numbers of cartilage cells. In other words, this study suggests that there is potential for progressive alterations in mandibular condyles in the elderly.

Ligament strain on the iliofemoral, pubofemoral, and ischiofemoral ligaments in cadaver specimens: biomechanical measurement and anatomical observation.

The iliofemoral, pubofemoral, and ischiofemoral ligaments are major structures that stabilize the hip joint. We have sought evidence on which to base more effective hip stretching positions. The purpose of this study was to measure strains on these ligaments and to observe them. Eight fresh/frozen translumbar cadaver specimens were used. Clinically available stretching positions for these ligaments were adopted. Strain on each ligament was measured by a displacement sensor during passive torque to the hip joint. Hip motion was measured using an electromagnetic tracking device. The strained ligaments were captured on clear photographs. Significantly, high strains were imposed on the superior iliofemoral ligament by external rotation of the hip (3.48%); on the inferior iliofemoral ligament by maximal extension and 10° or 20° of external rotation with maximal extension (1.86%, 1.46%, 1.25%); on the pubofemoral ligament by maximal abduction and 10°, 20°, or 30° of external rotation with maximal abduction (3.18%, 3.28%, 3.11%, 2.99%); and on the ischiofemoral ligament by 10° or 20° of abduction with maximal internal rotation (7.11%, 7.83%). Fiber direction in each ligament was clearly identified. Significantly, high strains on hip ligaments corresponded with the anatomical direction of the ligament fibers. Positions were identified for each ligament that imposed maximal increase in strain on it.

Nerves supplying the internal anal sphincter: an immunohistochemical study using donated elderly cadavers.

PURPOSE: Nerves serving the internal anal sphincter (NIAS) have been described as the lower rectal branches of the pelvic autonomic nerve plexus. However, their topographical anatomy and fiber components have remained unclear. METHODS: Using histological sections from ten elderly donated cadavers, we investigated the topographical anatomy and composite fibers of the NIAS using immunohistochemistry for S100 protein, neuronal nitric oxide synthase (nNOS), vasoactive intestinal polypeptide (VIP) and tyrosine hydroxylase (TH). RESULTS: At the 2-3 o'clock position in the lower rectum, the NIAS originated from nerves at the posterolateral corner of the prostate in males or in the lower paracolpium in females. The nerves ran inferiorly along the internal aspect of the levator ani muscle, and joined branches of the myenteric plexus at a level slightly above the epithelial junction. The NIAS contained both nNOS-positive parasympathetic nerve fibers and TH-positive sympathetic fibers, but VIP-positive fibers were few in number. CONCLUSIONS: The origin of the NIAS at the posterolateral corner of the prostate as well as in the lower paracolpium might be sacrificed or damaged during radical prostatectomy or tension-free vaginal tape insertion. Low anterior resection of rectal cancer will most likely render damage to the NIAS because of its intersphincteric course. Although the nerve composition of the NIAS is characterized by a higher proportion of sympathetic nerve fibers than the myenteric plexus in the large intestine, their role is unclear. However, evaluation of sphincteric function after surgery would appear to be difficult because of the complex control mechanism independent of nerve supply.

The popliteal eminence shows that the intra-articular popliteal tendon supports posterolateral knee stability.

The intra-articular popliteal tendon (iPT) is responsible for the dynamic stability of the posterolateral part of the knee joint. In this study, the involvement of the iPT in posterolateral stability in response to knee flexion was investigated anatomically. Thirty-one knees from thirty formalin-fixed room cadavers (17 male knees, 14 female knees; average age 86.9 years) were used. The knee was prepared with the distal 1/3 of the lower femur and crus and was flexed at 0°, 30°, 60°, and 90° in a special jig to limit knee rotation. The series of movements was plotted on the coordinate system using the Quadrant method. The iPT was in strong contact with a thick cartilage area, which we called the "popliteal eminence", at the lateral condyle of the femur. The average iPT angles with respect to the femoral axis were 28.78°, 49.79°, 77.74°, and 115.44° at knee flexion of 0°, 30°, 60°, and 90°, respectively. The iPT was strongly associated with the popliteal eminence at 29.5° in Type I and 27.09° in Type II knee flexion. The iPT has been conventionally regarded as a secondary restraint of posterior movement, acting as a stabilizer. However, the iPT appears to work more positively on knee joint stability because it was in strong enough contact to create the popliteal eminence. The iPT supports the femur in the posterolateral region in mild knee flexion.

Diabetes impairs the interactions between long-term hematopoietic stem cells and osteopontin-positive cells in the endosteal niche of mouse bone marrow.

Hematopoietic stem cells (HSCs) are maintained, and their division/proliferation and quiescence are regulated in the microenvironments, niches, in the bone marrow. Although diabetes is known to induce abnormalities in HSC mobilization and proliferation through chemokine and chemokine receptors, little is known about the interaction between long-term HSCs (LT-HSCs) and osteopontin-positive (OPN) cells in endosteal niche. To examine this interaction, LT-HSCs and OPN cells were isolated from streptozotocin-induced diabetic and nondiabetic mice. In diabetic mice, we observed a reduction in the number of LT-HSCs and OPN cells and impaired expression of Tie2, ß-catenin, and N-cadherin on LT-HSCs and ß1-integrin, ß-catenin, angiopoietin-1, and CXCL12 on OPN cells. In an in vitro coculture system, LT-HSCs isolated from nondiabetic mice exposed to diabetic OPN cells showed abnormal mRNA expression levels of Tie2 and N-cadherin. Conversely, in LT-HSCs derived from diabetic mice exposed to nondiabetic OPN cells, the decreased mRNA expressions of Tie2, ß-catenin, and N-cadherin were restored to normal levels. The effects of diabetic or nondiabetic OPN cells on LT-HSCs shown in this coculture system were confirmed by the coinjection of LT-HSCs and OPN cells into bone marrow of irradiated nondiabetic mice. Our results provide new insight into the treatment of diabetes-induced LT-HSC abnormalities and suggest that the replacement of OPN cells may represent a novel treatment strategy.