BepiColombo mission confirms stagnation region of Venus and reveals its large extent

The second Venus flyby of the BepiColombo mission offer a unique opportunity to make a complete tour of one of the few gas-dynamics dominated interaction regions between the supersonic solar wind and a Solar System object. The spacecraft pass through the full Venusian magnetosheath following the plasma streamlines, and cross the subsolar stagnation region during very stable solar wind conditions as observed upstream by the neighboring Solar Orbiter mission. These rare multipoint synergistic observations and stable conditions experimentally confirm what was previously predicted for the barely-explored stagnation region close to solar minimum. Here, we show that this region has a large extend, up to an altitude of 1900 km, and the estimated low energy transfer near the subsolar point confirm that the atmosphere of Venus, despite being non-magnetized and less conductive due to lower ultraviolet flux at solar minimum, is capable of withstanding the solar wind under low dynamic pressure.

Paratenon of the cruciate ligaments of the knee: a macroscopic and histological study of human fetuses

BACKGROUND

The paratenon is a sheath-like connective tissue that allows the tendon to move with minimal friction. The careful removal of the paratenon along the cruciate ligaments is a critical step of knee surgery. Thus, orthopedic surgeons and interventional radiologists consider the paratenon as a basic anatomical tissue along a ligament, not along a tendon.

MATERIALS AND METHODS

We performed macroscopic and histological observations of cruciate ligament-associated paratenons in 43 human fetuses.

RESULTS

This tissue usually had a thick armor-like appearance that was distant from the infrapatellar fat pad. The anterior cruciate ligament, rather than the posterior ligament, was deeply embedded in the paratenon. The paratenon contained abundant arteries and veins and, at and near the crossing between the cruciate ligaments, had a well-developed venous plexus. Notably, there were abundant fused veins in the paratenon venous plexus, and prenatal knee movements (especially rotation) seemed to restrict its blood supply, leading to the development of a large cavity by way of advancing fusion of veins in the degenerating plexus. This unique manner of cavitation likely expanded the joint cavity.

CONCLUSIONS

Differences in knee movements in utero seemed to cause differences in the thickness of the paratenon among fetuses. New-borns might have limited knee flexion due to a mass-effect of the thick paratenon around the cruciate ligaments. A slight twisting or rotation at the knee may help to release the knee, because it can break the fetal paratenon and accelerate cavitation.

Development and growth of the foot lumbricalis muscle: a histological study using human fetuses

Our group has shown early development of the hand lumbricalis and hypothesized that, at midterm, the lumbricalis (LU) bundles flexor tendons to provide a configuration of "one tendon per one finger" (Folia Morphologica 2012; 71:154). However, the study concentrated on the hand and contained no sections of near-term fetuses. The present examination of paraffin-embedded tangential sections along the planta from 25 embryos and fetuses at 6-40 weeks (15-320 mm crown-rump length or CRL) demonstrated that, at 8 weeks, the initial foot LU appeared in the proximal side of the common tendinous plate of all five deep tendons. After midterm, a drastic three phase change occurred at the muscle origin: 1) the LU originated from each of the flexor digitorum longus tendon (FDLT), but abundant tenocyte candidates separated the muscle fiber from the tendon collagen bundle; 2) the LU arose from the covering fascia depending on increased thickness of the muscle; and 3) the LU muscle fibers intermingled with tendon collagen bundles and partly surrounded the tendon. Simultaneously, a dividing site of the FDLT migrated distally to accelerate the changes at the LU origin. These phases did not always correspond to the size of fetus after 30 weeks. Consequently, in contrast to the hand LU, the delayed changes in the foot were characterized by involvement of the LU origin into a single common part of the FDLT. The quadratus plantae muscle fibers did not attach to the LU at any phase, and connected with the fourth and fifth toe tendons.

Changes in topographical relation between the ductus arteriosus and left subclavian artery in human embryos: a study using serial sagittal sections

BACKGROUND

At birth, the ductus arteriosus (DA) merges with the aortic arch in the slightly caudal side of the origin of the left subclavian artery (SCA). Since the SCAs (7th segmental arteries) were fixed on the level of the 7th cervical-first thoracic vertebral bodies, the confluence of DA should migrate caudally. We aimed to describe timing and sequence of the topographical change using serial sagittal sections of 36 human embryos and foetuses (CRL 8-64 mm; 5-10 weeks), Those made easy evaluation of the vertebral levels possible in a few section.

MATERIALS AND METHODS

The DA or 6th pharyngeal arch artery seemed to slide down in front of the sympathetic nerve trunk along 1.0-1.2 mm from the second cervical vertebral level at 5-6 weeks and, at 6 weeks (CRL 14-17 mm), the DA confluence with aorta reached the 7th cervical level. Because of the highly elongated common carotid artery, the sliding of DA confluence seemed to be much shorter than the cervical vertebrae growing from 1 mm to 2.4 mm.

RESULTS

At the final topographical change at 6-7 weeks, the DA confluence further descended to a site 1-vertebral length below the left SCA origin. From 6 to 9 weeks, a distance from the top of the aortic arch to the left SCA origin was almost stable: 0.3-0.5 mm at 6 weeks and 0.4-0.6 mm at 9 weeks.

CONCLUSIONS

The heart descent and the caudal extension of the trachea and bronchi, those occurred before the DA sliding, were likely to be a major driving force for the sliding.

Differences in foetal topographical anatomy between insertion sites of the iliopsoas and gluteus medius muscles into the proximal femur: a consideration of femoral torsion

BACKGROUND

Prenatal twisting of the femoral neck seems to result in an angle of anteversion or torsion, but the underlying process has not been elucidated.

MATERIALS AND METHODS

This study analysed sagittal, frontal and horizontal sections of 34 embryo and foetal specimens of gestational age (GA) 6-16 weeks (crown-rump length 21-130 mm). At GA 6-7 weeks, the iliopsoas (IP) and gluteus medius (GME) muscles were inserted into the anterior and posterior aspects of the femur, respectively, allowing both insertions to be viewed in a single sagittal section.

RESULTS

At GA 8 weeks, the greater trochanter and the femoral neck angle became evident, and the GME tendon was inserted into the upper tip of the trochanter. At GA 9 weeks, the location of IP insertion was to the medial side of the GME insertion. After 9 weeks, the IP insertion consisted of a wavy, tendino- us part of the psoas muscle and another part of the iliacus muscle, with many fibres of the latter muscle attached to the joint capsule. After GA 12 weeks, the IP was inserted into the anteromedial side of the greater trochanter, while the aponeurotic insertion of the GME wrapped around the trochanter. At GA 15-16 weeks, a deep flexion at the hip joint caused an alteration in the relative heights of the lesser and greater trochanter, with the former migrating from the inferior to the slightly superior side.

CONCLUSIONS

These findings indicate that twisting of the femoral neck started at GA 8-9 weeks.

Observations of foetal heart veins draining directly into the left and right atria

Evaluation of semiserial sections of 14 normal hearts from human foetuses of gestational age 25-33 weeks showed that all of these hearts contained thin veins draining directly into the atria (maximum, 10 veins per heart). Of the 75 veins in these 14 hearts, 55 emptied into the right atrium and 20 into the left atrium. These veins were not accompanied by nerves, in contrast to tributaries of the great cardiac vein, and were negative for both smooth muscle actin (SMA) and CD34. However, the epithelium and venous wall of the anterior cardiac vein, the thickest of the direct draining veins, were strongly positive for SMA and CD34, respectively. In general, developing fibres in the vascular wall were positive for CD34, while the endothelium of the arteries and veins was strongly positive for the present DAKO antibody of SMA. The small cardiac vein, a thin but permanent tributary of the terminal portion of the great cardiac vein, was also positive for SMA and CD34. A few S100 protein-positive nerves were observed along both the anterior and small cardiac veins, but no nerves accompanied the direct dra- inage veins. These findings suggested that the latter did not develop from the early epicardiac vascular plexus but from a gulfing of the intratrabecular space or sinus of the atria. However, the immunoreactivity of the anterior cardiac vein suggests that it originated from the vascular plexus, similar to tributaries of the great cardiac vein.

Rapid nongenomic modulation by neurosteroids of dendritic spines in the hippocampus: Androgen, oestrogen and corticosteroid

Memories are stored in synapses that consist of axon terminals and dendritic spines. Dendritic spines are postsynaptic structures of synapses and are essential for synaptic plasticity and cognition. Therefore, extensive investigations concerning the functions and structures of spines have been performed. Sex steroids and stress steroids have been shown to modulate hippocampal synapses. Although the rapid modulatory action of sex steroids on synapses has been studied in hippocampal neurones over several decades, the essential molecular mechanisms have not been fully understood. Here, a description of kinase-dependent signalling mechanisms is provided that can explain the rapid nongenomic modulation of dendritic spinogenesis in rat and mouse hippocampal slices by the application of sex steroids, including dihydrotestosterone, testosterone, oestradiol and progesterone. We also indicate the role of synaptic (classic) sex steroid receptors that trigger these rapid synaptic modulations. Moreover, we describe rapid nongenomic spine modulation by applying corticosterone, which is an acute stress model of the hippocampus. The explanations for the results obtained are mainly based on the optical imaging of dendritic spines. Comparisons are also performed with results obtained from other types of imaging, including electron microscopic imaging. Relationships between spine modulation and modulation of cognition are discussed. We recognise that most of rapid effects of exogenously applied oestrogen and androgen were observed in steroid-depleted conditions, including acute slices of the hippocampus, castrated male animals and ovariectomised female animals. Therefore, the previously observed effects can be considered as a type of recovery event, which may be essentially similar to hormone replacement therapy under hormone-decreased conditions. On the other hand, in gonadally intact young animals with high levels of endogenous sex hormones, further supplementation of sex hormones might not be effective, whereas the infusion of blockers for steroid receptors or kinases may be effective, with respect to suppressing sex hormone functions, thus providing useful information regarding molecular mechanisms.

Development of digastric muscles in human foetuses: a review and findings in the flexor digitorum superficialis muscle

The digastricus and omohyoideus muscles are digastric muscles with two muscle bellies. An insertion tendon of the posterior belly becomes an intermediate tendon in digastricus muscles, whereas a single band-like muscle in omohyoideus muscles may later be interrupted by an intermediate tendon, possibly due to muscle cell death caused by mechanical stress. In human foetuses, an intermediate tendon provides the temporal origins of the tensor veli palatini and tensor tympani muscles. Some reptiles, including snakes, carry multiple series of digastric-like axial muscles, in which each intersegmental septum is likely to become an intermediate tendon. These findings indicate that many pathways are involved in the development of digastric muscles. A review of these morphologies suggested that the flexor digi-torum superficialis (FDS) muscle was a digastric muscle, although the intermediate tendon may not be visible in the surface view in adults. The present observations support the hypothesis that the proximal anlage at the elbow develops into a deep muscle slip to a limited finger, while the distal anlage at the wrist develops into the other slips. The findings suggest that, in the FDS muscle, the proximal and distal bellies of the embryonic digastric muscle fuse together to form a laminar structure, in which muscle slips accumulate from the palmar to the deep side of the forearm. (Folia Morphol 2018; 77, 2: 362-370).

Foetal development of the human gluteus maximus muscle with special reference to its fascial insertion

The human gluteus maximus muscle (GMX) is characterised by its insertion to the iliotibial tract (a lateral thick fascia of the thigh beneath the fascia lata), which plays a critical role in lateral stabilisation of the hip joint during walking. In contrast, in non-human primates, the GMX and biceps femoris muscle provide a flexor complex. According to our observations of 15 human embryos and 11 foetuses at 7-10 weeks of gestation (21-55 mm), the GMX anlage was divided into 1) a superior part that developed earlier and 2) a small inferior part that developed later. The latter was adjacent to, or even continuous with, the biceps femoris. At 8 weeks, both parts inserted into the femur, possibly the future gluteal tuberosity. However, depending on traction by the developing inferior part as well as pressure from the developing major trochanter of the femur, most of the original femoral insertion of the GMX appeared to be detached from the femur. Therefore, at 9-10 weeks, the GMX had a digastric muscle-like appearance with an intermediate band connecting the major superior part to the small inferior mass. This band, most likely corresponding to the initial iliotibial tract, extended laterally and distally far from the muscle fibres. The fascia lata was still thin and the tensor fasciae latae seemed to develop much later. It seems likely that the evolutionary transition from quadripedality to bipedality and a permanently upright posture would require the development of a new GMX complex with the iliotibial tract that differs from that in non-human primates. (Folia Morphol 2018; 77, 1: 144-150).

Oblique cord (chorda obliqua) of the forearm and muscle-associated fibrous tissues at and around the elbow joint: a study of human foetal specimens

In adults, the oblique cord or chorda obliqua separates the origins of the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) muscles from the supinator muscle and elbow joint. This study examined the topographic anatomy of the oblique cord and related muscles in foetuses. Semiserial sections of five mid-term foetuses of gestational age (GA) 14-16 weeks and 12 late-stage foetuses of GA 28-30 weeks were histologically examined and three forearms at GA 30 weeks were macroscopically evaluated. Late-stage foetuses showed a fascial structure between the supinator and FDP muscles. The latter extended proximally to the elbow joint and the muscle origin thickened the distal, ulnar part of the capsule. The FPL origin also extended proximally but did not reach the joint capsule. These morphologies were consistent with macroscopic examinations. The brachialis muscle was widely inserted into the proximal, anterior part of the capsule. In addition, the medial collateral ligament was not covered by the pronator-flexor muscles but by the triceps brachii muscle. The oblique cord apparently did not form prenatally. After birth, the proximal parts of the FDP and FPL muscles were likely replaced by collagenous tissues, providing a specific type of intermuscular septum i.e., the oblique cord. This type of muscle-ligament transition was observed in the annular ligament of the radius. The foetal elbow joint was characterised by strong support by the FDP, brachialis and triceps brachii muscles. Therefore, the foetal elbow is not a miniature version of the adult elbow.

A new insight into the fabella at knee: the foetal development and evolution

Using longitudinal semiserial sections of 12 lower extremities from 8 human foetuses at 15-18 weeks, we compared foetal morphologies of the knee in specimens with and without fabellae. We also compared the fabella, if present, with the hallucal sesamoid in the same foetus. Cartilaginous fabella, positive for versican and tenascin by immunohistochemistry, was found in 5 of the 8 foetuses. This structure was embedded in a thick and tight lateral fibrous band, providing a common origin of the plantaris muscle and the lateral head of the gastrocnemius muscle. The plantaris was covered by the lateral head of the gastrocnemius, but these 2 muscles were separated by a distinct fascia or space. Notably, the foetal fabella did not attach to the joint capsule. In the 3 specimens without fabellae, the lateral fibrous band was thin, containing a fibrous mass, negative for versican and tenascin, in place of the fabella. The "medial" head of the gastrocnemius faced or covered the plantaris, while the lateral head was continuous with the plantaris. A hallucal cartilaginous sesamoid, positive for versican and tenascin, was present in all 8 specimens. It carried a flat surface facing the joint cavity and was covered by tendons of the short muscles of the foot. Because of the difference in topographical relation of muscles between specimens with or without fabella, rather than mechanical stress to the tendon, fabella development may require a distinct plantaris muscle independent of the gastrocnemius. We discussed about an evolutionary aspect of the fabella and plantaris muscle.

Lymphatic vessels around the uterus: D2-40 (podoplandin) immunohistochemistry using elderly cadavers

Using D2-40 immunohistochemistry, we examined the morphology of lymphatic vessels (LVs) in, along and around the uterus of 10 donated female cadavers (mean age, 85 years). All these women had 1 or 2 children with vaginal delivery, but the other obstetrics information was unknown. When compared with the bladder, vagina and the subperitoneal tissue, the percentage area of LVs in a 3 × 2 mm square including the hot spot was extremely high along the uterine artery and superficial uterine vein, in spite of the silent physiology of the elderly uterus. Notably, the LVs along the uterine artery and superficial uterine vein were highly dilated and embedded in the tight connective tissue around the artery and vein. In contrast, the LVs were separated from the artery and vein in the so-called vesico- -uterine ligament. Thus, surgical separation of the LVs from the artery and vein, i.e., skeletonisation, appears very difficult along the uterine artery and superficial uterine vein. This may become a major factor limiting the future application of robot-assisted surgery for uterine cancers.

Evidence for global electron transportation into the jovian inner magnetosphere

Jupiter's magnetosphere is a strong particle accelerator that contains ultrarelativistic electrons in its inner part. They are thought to be accelerated by whistler-mode waves excited by anisotropic hot electrons (>10 kiloelectron volts) injected from the outer magnetosphere. However, electron transportation in the inner magnetosphere is not well understood. By analyzing the extreme ultraviolet line emission from the inner magnetosphere, we show evidence for global inward transport of flux tubes containing hot plasma. High-spectral-resolution scanning observations of the Io plasma torus in the inner magnetosphere enable us to generate radial profiles of the hot electron fraction. It gradually decreases with decreasing radial distance, despite the short collisional time scale that should thermalize them rapidly. This indicates a fast and continuous resupply of hot electrons responsible for exciting the whistler-mode waves.

An immunohistochemical study of matrix proteins in the craniofacial cartilage in midterm human fetuses

Immunohistochemical localization of collagen types I, II, and X, aggrecan, versican, dentin matrix protein (DMP)-1, martix extracellular phosphoprotein (MEPE) were performed for Meckel's cartilage, cranial base cartilage, and mandibular condylar cartilage in human midterm fetuses; staining patterns within the condylar cartilage were compared to those within other cartilaginous structures. Mandibular condylar cartilage contained aggrecan; it also had more type I collagen and a thicker hypertrophic cell layer than the other two types of cartilage; these three characteristics are similar to those of the secondary cartilage of rodents. MEPE immunoreactivity was first evident in the cartilage matrix of all types of cartilage in the human fetuses and in Meckel's cartilage of mice and rats. MEPE immunoreactivity was enhanced in the deep layer of the hypertrophic cell layer and in the cartilaginous core of the bone trabeculae in the primary spongiosa. These results indicated that MEPE is a component of cartilage matrix and may be involved in cartilage mineralization. DMP-1 immunoreactivity first became evident in human bone lacunae walls and canaliculi; this pattern of expression was comparable to the pattern seen in rodents. In addition, chondroid bone was evident in the mandibular (glenoid) fossa of the temporal bone, and it had aggrecan, collagen types I and X, MEPE, and DMP-1 immunoreactivity; these findings indicated that chondroid bone in this region has phenotypic expression indicative of both hypertrophic chondrocytes and osteocytes.

An artery accompanying the sciatic nerve (arteria comitans nervi ischiadici) and the position of the hip joint: a comparative histological study using chick, mouse, and human foetal specimens

Birds and reptiles always carry a long and thick artery accompanying the sciatic nerve (i.e., the sciatic artery), whereas mammals do not. We attempted to demonstrate a difference in courses of the nerve and artery in fetuses in relation with the hip joint posture. Eight mid-term human fetuses (15-18 weeks), five mouse fetuses (E18) and five chick embryos (11 days after incubation) were examined histologically. Thin feeding arteries in the sciatic nerve were consistently observed in human fetuses in spite of the long, inferiorly curved course of the nerve around the ischium. The tissue around the human sciatic nerve was not so tight because of the medial and inferior shift of the nerve away from the hip joint. The fetal hip joint position differed among the species, being highly flexed in humans and almost at right angle flexion in mice and chicks. Because of deep adduction of the hip joint in the mouse, the knee was located near the midline of the body. The mouse sciatic nerve ran through the tight tissue along the head of the femur, whereas the chick nerve ran through the loose space even in the gluteal region. In birds, evolution of the pelvis including the hip joint without adduction seemed to make the arterial development possible. In mammals, highly flexed or adducted hip joint seemed to be one of the disturbing factors against development of the long and thick artery. A slight change in posture may cause significant arterial variation.

Reappraisal of the ligament of Henle (ligamentum inguinale internum mediale; Henle, 1871): a topohistological study using Korean foetuses

Ligament of Henle is one of muscle-associated connective tissues of the rectus abdominis muscle, but it has been confused with the conjoint tendon (a common aponeurosis for insertion of the inferomedial end of the obliquus internus and transversus abdominis muscles). To reconsider the inguinal connective tissue structures, we examined 20 mid-term foetuses (10 males and 10 females) at approximately 14-20 weeks of gestation (crown rump length 100-170 mm). In female horizontal sections, we consistently found the ligament of Henle asa wing-like aponeurosis extending from the lateral margin of the rectus tendon behind the superficial inguinal ring. The ligament was separated from and located behind the conjoint tendon. In all male foetuses, instead of the ligament, the conjoint tendon was evident behind the superficial ring and it winded around the posterior aspect of the spermatic cord. Therefore, although a limited number of specimens were examined, the ligament of Henle was likely to be a female-specific structure. The ligament of Henle, if developed well, may provide an arch-like structure suitable for a name "falx inguinalis" instead of the inferomedial end ofthe conjoint tendon. In addition, a covering fascia of the iliopsoas muscle joined the posterior wall of the inguinal canal in male, but not in female, specimens.

High sensitivity microchannel plate detectors for space extreme ultraviolet missions

Microchannel plate (MCP) detectors have been widely used as two-dimensional photon counting devices on numerous space EUV (extreme ultraviolet) missions. Although there are other choices for EUV photon detectors, the characteristic features of MCP detectors such as their light weight, low dark current, and high spatial resolution make them more desirable for space applications than any other detector. In addition, it is known that the photocathode can be tailored to increase the quantum detection efficiency (QDE) especially for longer UV wavelengths (100-150 nm). There are many types of photocathode materials available, typically alkali halides. In this study, we report on the EUV (50-150 nm) QDE evaluations for MCPs that were coated with Au, MgF(2), CsI, and KBr. We confirmed that CsI and KBr show 2-100 times higher QDEs than the bare photocathode MCPs, while Au and MgF(2) show reduced QDEs. In addition, the optimal geometrical parameters for the CsI deposition were also studied experimentally. The best CsI thickness was found to be 150 nm, and it should be deposited on the inner wall of the channels only where the EUV photons initially impinge. We will also discuss the techniques and procedures for reducing the degradation of the photocathode while it is being prepared on the ground before being deployed in space, as adopted by JAXA's EXCEED mission which will be launched in 2013.

Development of the deep flexor tendons and lumbricalis muscle in the hand and foot: a histological study using human mid-term foetuses

To revisit foetal development of the deep flexor tendons of the hand and foot, we examined the paraffin-embedded histology of 20 mid-term foetuses at 8-15 weeks of estimated gestational age (35-118 mm crown-rump length or CRL). At 8-9 weeks, in front of the metacarpal bones, the flexor pollicis longus and flexor digitorum profundus (FDP) muscles provided a plate-like, common tendon from which the lumbricalis muscles originated. However, in the foot, we had no evidence of such a common tendon. The flexor pollicis tendon was separated from the common tendon at 9-10 weeks possibly due to mechanical stress from the laterally growing thumb. Notably, at the lumbricalis muscle origins at 10-12 weeks, the FDP and flexor digitorum longus tendons remained undifferentiated and the primitive tenocytes were dispersed from them. The dispersed cells seemed to develop into an interface tissue between the lumbricalis muscle fibre and the deep tendon. In 3 of 5 specimens at 15 weeks, we found an excess number of the FDP tendons (5-7) in the proximal side of the lumbricalis muscle origin. However, the excess tendons dispersed in the lumbricalis muscle origin. The development of the lumbricalis muscle origin might follow the tendon splitting for four fingers. However, conversely, we hypothesised that the developing lumbricalis muscles re-arranged the deep flexor tendons to provide a configuration of one deep tendon per one finger (or toe). The quadrates plantae muscle seemed not to contribute on the re-arrangement.

Fetal developmental change in topographical relationship between the human lateral pterygoid muscle and buccal nerve

In adults, the lateral pterygoid muscle (LPM) is usually divided into the upper and lower heads, between which the buccal nerve passes. Using sagittal or horizontal sections of 14 fetuses and seven embryos (five specimens at approximately 20-25 weeks; five at 14-16 weeks; four at 8 weeks; seven at 6-7 weeks), we examined the topographical relationship between the LPM and the buccal nerve. In large fetuses later than 15 weeks, the upper head of the LPM was clearly discriminated from the lower head. However, the upper head was much smaller than the lower head in the smaller fetuses. Thus, in the latter, the upper head was better described as an 'anterior slip' extending from the lower head or the major muscle mass to the anterior side of the buccal nerve. The postero-anterior nerve course seemed to be determined by a branch to the temporalis muscle (i.e. the anterior deep temporal nerve). At 8 weeks, the buccal nerve passed through the roof of the small, fan-like LPM. At 6-7 weeks, the LPM anlage was embedded between the temporobuccal nerve trunk and the inferior alveolar nerve. Therefore, parts of the LPM were likely to 'leak' out of slits between the origins of the mandibular nerve branches at 7-8 weeks, and seemed to grow in size during weeks 14-20 and extend anterosuperiorly along the infratemporal surface of the prominently developing greater wing of the sphenoid bone. Consequently, the topographical relationship between the LPM and the buccal nerve appeared to 'change' during fetal development due to delayed development of the upper head.

Relationships among estrogen receptor, oxytocin and vasopressin gene expression and social interaction in male mice

The incidence of social disorders such as autism and schizophrenia is significantly higher in males, and the presentation more severe, than in females. This suggests the possible contribution of sex hormones to the development of these psychiatric disorders. There is also evidence that these disorders are highly heritable. To contribute toward our understanding of the mechanisms underlying social behaviors, particularly social interaction, we assessed the relationship of social interaction with gene expression for two neuropeptides, oxytocin (OT) and arginine vasopressin (AVP), using adult male mice. Social interaction was positively correlated with: oxytocin receptor (OTR) and vasopressin receptor (V1aR) mRNA expression in the medial amygdala; and OT and AVP mRNA expression in the paraventricular nucleus of the hypothalamus (PVN). When mice representing extremes of social interaction were compared, all of these mRNAs were more highly expressed in high social interaction mice than in low social interaction mice. OTR and V1aR mRNAs were highly correlated with estrogen receptor α (ERα) mRNA in the medial amygdala, and OT and AVP mRNAs with estrogen receptor β (ERβ) mRNA in the PVN, indicating that OT and AVP systems are tightly regulated by estrogen receptors. A significant difference in the level of ERα mRNA in the medial amygdala between high and low social interaction mice was also observed. These results support the hypothesis that variations of estrogen receptor levels are associated with differences in social interaction through the OT and AVP systems, by upregulating gene expression for those peptides and their receptors.

Histological identification of fascial structures posterolateral to the rectum

BACKGROUND

A comprehensive understanding of fascial structures around the rectum is important for surgeons. Multilaminar fascial structures have provided different interpretations of reliable surgical planes in rectal surgery.

METHODS

Pelvic visceral materials for histological assessment were obtained from 12 male cadavers. Large specimens covering wide areas around the mesorectum were embedded in paraffin, followed by preparation of semiserial horizontal sections and sagittal sections for histological examination.

RESULTS

Histological examination demonstrated a prehypogastric nerve fascia and parietal presacral fascia in the retrorectal multilaminar structure. The parietal presacral fascia seemed to divide into several lateral continuations. The prehypogastric nerve fascia appeared to join the most medial continuation of the parietal presacral fascia, which continued ventrally and communicated with Denonvilliers' fascia. Any fascial structure connecting directly between the fascia propria of the rectum and the parietal presacral fascia (that is, the rectosacral fascia) was not found in sagittal sections.

CONCLUSION

In the retrorectal multilaminar structure, prehypogastric nerve fascia is evident between the fascia propria of the rectum and the parietal presacral fascia. Sharp dissection in front of the prehypogastric nerve fascia according to the histological configuration of the posterolateral fasciae seems reliable.

Vesicouterine ligament contains abundant autonomic nerve ganglion cells: the distribution in histology concerning nerve-sparing radical hysterectomy

The aim of this study is to describe the histologic architecture of the tissues corresponding to the surgically developed connective tissue bundle commonly referred to as the posterior leaf of the vesico-uterine ligament (VUL), and to examine distribution of ganglion cells. Serial macroscopic slices, each 15-20 mm in thickness, were made from eight specimens (obtained from six female elderly cadavers). In these macroslices, the location of the deep uterine vein was used to identify the deep leaf of the VUL. The specimens were trimmed and semi-serial histologic sections in thickness were prepared at 1 mm intervals. Vesical veins and the associated nerve elements were enclosed by fascia and formed a common pedicle. The base of the pedicle contained the deep uterine vein trunk. The fascia encircling the pedicle varied in thickness and connective intensity between specimens. This vesical neurovascular bundle contained abundant ganglion cells. On average, 48.0% of the ganglion cells along the vesical tributaries of the deep uterine vein were located on the medial or vaginal side of the veins, 19.2% were located between veins, 13.0% on the lateral side of the veins, and 19.8% on the dorsal side. The interindividual variability was greatest on the dorsal side of vesical veins and ranged 11-202 cells. We conclude that in order to achieve maximal preservation of the ganglion cells during the surgical dissection of the posterior leaf of the VUL, care must be taken when the medial or vesical aspect of the ligament is separated. The standard nerve-sparing radical hysterectomy should be modified to reflect differences in the distribution of ganglion cells and in connective intensity between ganglions and veins.

Arterial supply and biliary drainage of the dorsal liver: a dissection study using controlled specimens

Liver surgeons favor using the entity called the 'dorsal liver' (i.e. the caudate lobe and other paracavally located liver parenchyme of segments 7 and 8). According to minute dissection of 48 livers, we describe the territories of the left/right portal veins, hepatic ducts and hepatic arteries in the dorsal liver. In the caudate lobe, the right hepatic artery, rather than the left hepatic artery (23/48 vs 19/48 for right vs left, respectively), tended to supply the 'left' portal vein territory. Similarly, paradoxical drainage patterns, such as the right hepatic duct draining the left portal vein territory, were found in seven of 48 livers. In the territory of the hilar bifurcation, right hepatic artery dominance was also evident and various bile drainage patterns were found. These included double drainage by the bilateral hepatic ducts (3/48) and drainage into the confluence of bilateral ducts (6/48). In contrast, the arterial supply and biliary drainage of the paracavally located parenchyme of segments 7 and 8 usually depended on the proper segmental arteries and ducts and their variations were within the range of those found in other parts of the right lobe. Therefore, the dorsal liver concept may not be anatomical but, rather, simply aimed at usefulness in surgery. Nevertheless, clear subdivision of the caudate lobe according to biliary drainage and/or arterial supply seemed difficult because of the paradoxical relatioships among the portal vein, hepatic artery and bile duct. Consequently, the present results support extended surgery based on the dorsal liver concept for carcinomas involving the caudate lobe.

Left lobe hypoplasia of the human liver: a report of two cases

Two cases of left lobe hypoplasia of the human liver were dissected minutely to show the intrahepatic vessels and ducts. In the left side of the round ligament, one case had a large cyst-like mass containing dilated vessels and ducts, while the other was accompanied by three rugby-ball-like parenchymal masses, each of which was covered by the peritoneum. The former specimen carried the usual Spiegel's lobe, while the latter was very small. Fascial and peritoneal fusion was evident at and around these two left lobes. In both cases the left hepatic vein showed the usual course and terminal end, segment IV was present to a greater or lesser degree. Thus, we hypothesized that, due to fascial and peritoneal fusion, membranous stricture occurred at the peripheral portions of the left portal trunk and left hepatic duct. The discussion focuses on a comparison of intrahepatic vascular configurations in four recently reported cases, including the present two livers.

Lymph node hyalinization in elderly Japanese

Lymph node hyalinization has been comprehensively investigated using specimens obtained from elderly Japanese and white Americans. Onion-peel lesions and associated meshwork areas were often found in the medullary sinus of the thoracic node (mediastinal-type hyalinization), while eosinophilic, glassy and spotty lesions were consistently seen in B lymphocyte areas of the pelvic node (pelvic-type hyalinization). The mediastinal-type hyalinization was comprised of thin collagen fibrils (ca 50 nm in diameter), whereas the pelvic-type hyalinization had thick fibrils (ca 150 nm in diameter). This difference seemed to be consistent with a difference in composite collagen fibrils of vascular walls between the thoracic and pelvic regions. The pelvic-type hyalinization was often or sometimes seen in other nodes, such as cervical, axillary, abdominal and inguinal nodes, especially in white Americans. The mediastinal-type hyalinization, usually in combination with a sinus filled with anthracotic macrophages, tended to be observed in Japanese more frequently than in white Americans. Anthracosis seemed to be connected to the pathogenesis of the hyalinization. On the other hand, because the lesion was weakly positive for Factor VIII immunohistochemistry and because lesions were located along thin vessels, the pelvic-type hyalinization seemed to originate from vascular degeneration in the nodal cortex. Due to the high incidence and large proportion in total volume of the node, the hyalinization seems to be one of the major events that diminish the nodal filtration function and ruin the node with aging.

High dorsal drainage routes of Spiegel's lobe

BACKGROUND/PURPOSE

The venous drainage from Spiegel's lobe to the terminal portion of the hepatic veins has been described in the literature, but its morphology remains unclear.

METHODS

We examined 42 dissected liver specimens and 38 cast specimens.

RESULTS

In 8 of the 42 dissected liver specimens and 5 of the 38 cast specimens we found atypical but thick (over 3 mm) caudate veins that drained Spiegel's lobe and emptied into the terminal portion (along the most proximal 5-mm course) of the middle hepatic vein (MHV) or the inferior vena cava (IVC) near the MHV terminal (less than 10 mm from the MHV). We termed these the superior caudate vein. This vein ran upward between the caudate portal branches of the left and hilar bifurcation origins or through the territory of the left origin. The superior caudate vein, consistently coexisted with the typical vein(s). We also found several analogues of the superior caudate vein, such as the cranially shifted opening of the typical caudate vein and relatively thick proximal tributaries of the MHV from Spiegel's lobe.

CONCLUSIONS

Although the superior caudate vein, if present, seemed to have a large role in the venous drainage of the lobe, its incidence seemed to be too low for clinical relevance.

Morphometrical study of the arterial perforators of the deep inferior epigastric perforator flap

Although abdominal perforator flaps based on a cutaneous branch of the deep inferior epigastric artery (DIEP flaps) have many advantages, preparing these flaps is technically difficult and requires great skill, especially as the portion of the artery running under the anterior rectus abdominis sheath must be operated upon "blind". To allow easier preparation and elevation of a DIEP flap pedicle, we propose that the arterial perforator should: 1) be more than 1.0 mm large; 2) run a straight intramuscular course, parallel to the rectus abdominis m. fibers, with no large muscular branches; and 3) have only a short portion running immediately under the anterior rectus abdominis sheath. We examined 329 perforators (more than 0.5 mm in diameter at the anterior sheath) in 66 rectus abdominis mm. from 33 cadavers among them: 1) 52 "large" perforators were over 1.0 mm in diameter; 2) 107 "suitable" perforators ran parallel to the muscle fibers without giving off large muscular branches; and 3) 35 "ideal" perforators combined these characteristics. The ideal perforators were usually located in the mid-abdominal region, 10-30 mm lateral to the umbilicus. The suitable perforators were usually present, often in combination with the ideal perforator(s), in a restricted area 20 mm cranial and 40-50 mm lateral to the umbilicus. We classified the course and ramification pattern of the deep inferior epigastric a. into six patterns, depending on whether the anastomosis was sited in the medial or lateral branch and the level at which the branches originated.

Regional specificity in degenerative changes in finger joints: an anatomical study using cadavers of the elderly

Rehabilitation therapists and orthopedists regard degenerative changes (DCs) of the articular cartilage or osteoarthritis in the finger joint as the major factors that interfere with normal grasp and pinch. However, previous research has concentrated on DCs in the carpometacarpal joint (CM) of the thumb. The present study revealed some general tendencies concerning the occurrence of DCs: (1) distal joint dominance between joints in a thumb or finger; (2) distal surface dominance in a joint; (3) radioulnar dominance in a joint; and (4) fifth-finger specificity (i.e., high incidences of both DCs and osteophytes). Moreover, according to our evaluation of multiple and solitary occurrences (i.e., how many segments carried DCs) we consider that DCs in the radioulnar segments advance not only to the complementary surface (i.e., mirror-image lesion formation) but also to other adjacent segments in the early stage before progression to cartilage defects occurs in the primarily affected segment. In addition, osteophytes were not associated with the cartilage defect in the adjacent segment, but, rather, occurred at opposite or distant segments in the joint. These results are discussed in relation to lateral pinch and precision grasping, with special reference to the hypothetical stress on these movements in the finger joint.

Origin of the thoracic duct and pancreaticoduodenal lymphatic pathways to the para-aortic lymph nodes

We investigated the afferent and efferent connections of the para-aortic lymph nodes (group 16 nodes) relative to the origin of the thoracic duct in 85 postmortem cadavers. The origin was usually restricted to groups 16b1-inter and -latero nodes (type I; 90.6%), regardless of whether the union of their efferents occurred at the abdominal or thoracic level. We also occasionally observed thick collecting vessels originating from the dorsal aspect of the pancreaticoduodenal region, running along the right side of and superficial to the celiac plexus and emptying into group 16b1 nodes. The thoracic duct originated occasionally not only from group 16b1 nodes but also from group 16a2 nodes (type II; 9.4%). Moreover, in all 85 specimens, the group 16a2-inter node often received afferents from the celiac plexus itself or the tight connective tissue between the plexus and diaphragmatic crus, or both. The results support the reliability of the extended D2 lymphadenectomy (D2 + group 16b1 nodes + group 16a2-inter node) for curative cancer surgery in the pancreaticoduodenal region.

Treatment of ischial pressure ulcers with a posteromedial thigh fasciocutaneous flap

This study describes the use of the posteromedial thigh fasciocutaneous flap for the treatment of ischial pressure sores. The authors prefer this flap because it is the fasciocutaneous flap nearest to the ischial region, it is easy to raise, and it causes no donor-site morbidity. In this study, 11 ischial pressure sores in 10 paraplegic patients were closed using the posteromedial thigh fasciocutaneous flaps. All flaps survived, although two caused distal necrosis; after these same two flaps were readvanced, they survived. After an average follow-up time of 77 months, seven of the 10 patients have had no recurrence of ulcers. This fasciocutaneous flap was previously described by Wang et al. However, this study revealed that the arrangement of the vascular pedicle was different from that described by Wang et al. To reveal the vascular supply of this flap, anatomic dissections were conducted. The source of circulation to this flap was the suprafascial vascular plexus, in addition to the musculocutaneous perforator. The dominant pedicle was the musculocutaneous perforator from either the adductor magnus muscle or the gracilis muscle. The key to safe elevation of this flap was the accurate outlining of the skin island directly over the vascular pedicle and the preservation of the proximal fascial continuity. Of the 11 flaps, two viability problems occurred. These partial flap losses resulted from the failure to properly include the perforator. It is the authors' conclusion that the width of the flap should be greater than 5 cm. In addition, it is safe to make a flap within a 1:3 base-to-length ratio in a fatty, diabetic patient. This posteromedial thigh fasciocutaneous flap was found to be a valuable alternative for reconstruction of primary or recurrent ischial pressure ulcers.

Blood supply to the duodenal papilla and the communicating artery between the anterior and posterior pancreaticoduodenal arterial arcades

The communicating artery (ComA) between the anterior and posterior pancreaticoduodenal arterial arcades is little understood, although it has been described several times during the past 100 years. In 44 of 51 cadaveric specimens in the present study, the typical ComA was observed to pass between the major and accessory pancreatic ducts. In addition, a second ComA was sometimes found crossing inferior to the major pancreatic duct. The typical ComAs often (36 of the 44) issued papillary branch(es). Although direct papillary branches of the posterior arcade were often observed to either coexist with (9 specimens) or exist independently (4 specimens), the ComA-derived branch seemed to be critical for papillary blood supply, because of its shorter length, greater thickness, and higher frequency. Moreover, the typical ComA could be a good landmark during limited pancreatic resection, such as duodenum-preserving subtotal resection of the pancreatic head or pancreatic segment resection, because the artery is likely to be an indicator of the borders between the celiac and superior mesenteric arterial territories, as well as those between the ventral and dorsal segments of the pancreas.

Ventral margin of the paracaval portion of human caudate lobe

The topographic anatomy of the ventral margin of the caudate lobe of the human liver is still obscure. We hypothesized the existence of a "precaudate plane", as a flat or slightly curved plane defined by the ventral margins of both the ligamentum venosum and hilar plate. Using 61 cadaveric liver specimens, without great differences in external shape or significant variations in the hilar bifurcation, we examined whether the paracaval caudate branches (PCs) ran through the plane to the ventral side. In 22 of the 61 specimens (36.1%), the PC extended over the plane for less than 10 mm (10 specimens), for 10-20 mm (7 specimens), or for more than 20 mm (5 specimens). The ventral extension consistently included the dome-like area under the terminals of the middle and right hepatic veins. Therefore, the ventrally extended PCs often interdigitated with these veins and their tributaries. The ventral extension often reached the upper, diaphragmatic surface. However, several branches were too difficult to discriminate from the PC, especially those with morphologies intermediate between the PC and segmental portal branches to S4 or S2. We discuss how to identify and manage the ventrally extended PCs before and during surgery.

Increased lymphoid MxA expression in acute asthma exacerbation in children

BACKGROUND

Although the association between acute asthma exacerbation and viral infection has been well documented, virus identification rates vary. It has recently been reported that the expression of MxA protein in lymphocytes, inducible by type I interferons, can serve as a sensitive marker for viral infection in the host. The objective was to determine the contribution of viral infection to precipitation of asthma attacks in children.

METHODS

We studied 186 asthmatic children, aged 0-12 years, over a 1-year period to evaluate MxA protein levels in peripheral blood lymphocytes by using a flow cytometric analysis in whole blood.

RESULTS

Of all the subjects, 80 (47%) exhibited significantly elevated levels of MxA expression in lymphocytes, presumably indicating the states of viral infection. The association of viral infections with acute asthma exacerbation seemed to be marked in younger children: enhanced MxA expression was seen in 73.3% of infants (aged 0-1 year), 49.5% of toddlers (aged 2-5 years), and 26% of schoolchildren (aged 6-12 years). Seasonal changes in the frequency of viral infection associated with deterioration were also observed.

CONCLUSIONS

Flow cytometric assay of MxA protein expression in whole blood appears to be an easy and useful method to evaluate viral infections in acute asthma exacerbation.

Early anchoring collagen fibers at the bone-tendon interface are conducted by woven bone formation: light microscope and scanning electron microscope observation using a canine model

To clarify the early process of recovery at the bone-tendon interface, we used light microscopy and SEM to examine the process of anchoring of collagen fibers to bone in a canine model. At two weeks, tendon, scar tissue, woven bone and lamellar bone were present at the insertion site. SEM revealed anchoring of collagen fibril bundles of the scar to the woven bone. By 4 weeks, the number of anchoring fibers had increased and a parallel arrangement of fibers was observed. SEM demonstrated deep penetration of fibers into the woven bone layer. In addition, the fibers were observed to project into and intermingle with the scar tissue. By 6 weeks, the anchoring fibers had developed fully and were distributed densely over the interface. SEM also revealed that the collagen fibril bundles in the scar tissue had connected with the collagen fibrils of the woven bone by way of the anchoring bundles. The woven bone was identifiable throughout the early stages of recovery as the interface between soft tissue and hard tissue. Throughout all experimental periods, no staining was observed at the interface of the tendon and bone by Saffranin-O. The formation of woven bone was important during early recovery of the tendon-bone interface prior to the completion of fibrocartilage-mediated insertion.

Ramification pattern and topographical relationship between the portal and hepatic veins in the left anatomical lobe of the human liver

Sixty-one human livers obtained from donated Japanese adult cadavers were dissected to reveal the ramification pattern of the portal and hepatic veins, and their topographical relationship in the left anatomical lobe. The segmental portal vein supplying S2 (P2) tended to form a single stem, whereas that of S3 (P3) was usually double. An intermediate branch between P2 and P3 was observed in 23.0% of livers. In spite of variation between livers, definite P2 and P3 were identified in 47 specimens. One tributary of the left hepatic vein (LHV) was usually present for drainage of S2, and two tributaries were present for S3 (sometimes also for S2 and/or S4). The latter two tributaries of the LHV and the two subsegmental branches of S3 showed three patterns of three-dimensional interdigitations. From these results, the portal vein system did not seem to have a two segmental composition (i.e., S2 and S3) in 23.0% of specimens, whereas the hepatic vein system did not have an intersegmental course in 23.4%. Thus, there were obvious limitations in using each system to determine the liver segment. Taking the overlapping cases into consideration, the left anatomical lobe of 41.0% of specimens did not seem to fit the definition of Couinaud's liver segment. In addition, four patterns of fissure vein (or scissural vein), > 5 mm in diameter at its terminal, were identified: (1) middle hepatic vein type (left median vein, 9.8%); (2) LHV type (left medial vein, 41.0%); (3) true fissure vein (3.3%); and (4) absent cases (45.9%). The former two types also suggested limitations of the hepatic vein system as an indicator of the segmental border.

First cutaneous branch of the internal pudendal artery: an anatomical basis for the so-called gluteal fold flap

We investigated the cutaneous blood supply in the gluteal and perineal regions of 35 donated cadavers to provide an anatomical basis for reliable vulvo-vaginal reconstruction using a skin flap such as the so-called gluteal fold flap. The cutaneous areas along the gluteal cleft and sulcus were likely to be supplied by 3 routes: 1) the internal pudendal artery (IPA), especially its first cutaneous branch; 2) perforators running through the gluteus maximus muscle and arising from the inferior gluteal artery (IGA); and 3) a non-perforator running around and inferior to the ischial tuberosity and originating from the IGA. Route 1 supplied the skin along the gluteal cleft, route 2 the gluteal fold (i.e., a bulky skin fold along the upper edge of the gluteal sulcus), and route 3, just along the gluteal sulcus. In those 3 routes, we noted the consistent morphology of the thick and long, first cutaneous branch of the IPA. The first arterial branch, 1.5 mm in diameter at its origin on average (ranging from 0.7-2.6 mm), usually originated from the IPA under the cover of or at the inferomedial or distal side of the sacrotuberous ligament (almost always less than 20 mm from the inferomedial margin of the ligament). The branch ran superomedially toward the coccyx or ran medially in the ischiorectal fat. It accompanied the vein and nerve at its distal (peripheral) course although the nerve often ran independently at its proxomal course near the ligament. Therefore, the first branch of the IPA seems to provide a reliable pedicle using the skin along the gluteal cleft whether the incision for approach is conducted along the gluteal sulcus or not. However, if the gluteus maximus muscle extended much inferomedially, the pedicle would be very short. In this case, preparation of the pedicle seems to be necessary along the arterial course under the cover of the muscle.

Liver segment S2 is consistently located at the dorsal side of S3 but sometimes at the right and/or caudal side of S3

After preparing the frontal section including the origin of the left portal trunk at the hilar region, the left anatomical lobes of 111 human livers were dissected to reveal the segmental configuration based on the supplying portal vein branches. S2 was consistently located dorsal to S3. However, in contrast to the description in common textbooks for medical students, 19.8% of the specimens carried a paradoxical segmental configuration showing a "caudal and/or rightward" S2 in combination with a "cranial and/or leftward" S3 in the frontal section through the ventral part of the hilar region. The caudal and rightward cases were associated with a specific arrangement of S2 and S3 segmental stems in which the S3 stem ran relatively upward to spread over S2 or both stems ran almost horizontal, respectively. In routine diagnostic radiology, identification of S2 and S3 might sometimes be biased by the generally accepted notion that S2 should be located at the dorsal, cranial and left side of S3.

Smurf1 interacts with transforming growth factor-beta type I receptor through Smad7 and induces receptor degradation

Smad7 is an inhibitory Smad that acts as a negative regulator of signaling by the transforming growth factor-beta (TGF-beta) superfamily proteins. Smad7 is induced by TGF-beta, stably interacts with activated TGF-beta type I receptor (TbetaR-I), and interferes with the phosphorylation of receptor-regulated Smads. Here we show that Smurf1, an E3 ubiquitin ligase for bone morphogenetic protein-specific Smads, also interacts with Smad7 and induces Smad7 ubiquitination and translocation into the cytoplasm. In addition, Smurf1 associates with TbetaR-I via Smad7, with subsequent enhancement of turnover of TbetaR-I and Smad7. These results thus reveal a novel function of Smad7, i.e. induction of degradation of TbetaR-I through recruitment of an E3 ligase to the receptor.

[Configuration of the liver segment observed in the frontal section including the origin of the left portal trunk at the hepatic hilum]

After preparing threparing the frontal section including the origin of the left portal trunk at the hepatic hilum, 60 human livers (35, entirely; 25, partly) were dissected to reveal segmental configuration and the supplying portal vein branches. We usually observed two combinations of segments, i.e., S2, 4, 5 and 8 or S2, 3, 4, 5 and 8, in the frontal section including the origin of the left portal trunk. However, S8 was sometimes absent in the section when S4 extended to the right and/or upper side. S2 was consistently located dorsal to S3 despite the fact that 11.7% of the specimens carried an unexpected configuration showing a "lower" S2 in combined with an "upper" S3 in the frontal section. The latter case was associated with specific S2 and S3 segmental branches maintaining horizontal courses along a common plane. S4, S5 and S8 were usually arranged from the ventral to the dorsal aspect in this order. Four types of ventral short branches originated at or near the primary portal divisions and supplied the hilar parenchyme adjacent to S4 and/or the anterior segment (S5 or S8). These ventral short branches tended to be associated with the variations of the primary division. Dissection of the liver after frontal section provided a better understanding of the segmental configuration rather than an approach from the hepatic hilum.

Fibrous connection to bone after immediate repair of the canine infraspinatus: the most effective bony surface for tendon attachment

The purpose of this histologic study was to identify the most effective bony surface for fibrous connection to bone after immediate repair of the canine infraspinatus. Light microscopic views were used to evaluate collagen fiber development. The left infraspinatus tendon of 15 dogs was transected and repaired to 3 different bone surfaces: a tendon end adjacent to the tendon insertion (group 1, n = 5), a calcified fibrocartilage layer (group 2, n = 5), and a cancellous surface (group 3, n = 5). Tendon repair to distal tendon ends restored the 4-layered enthesis in the healing period, whereas tendon repair to the calcified fibrocartilage layer considerably delayed fiber development into bone. Fiber connection to cancellous surface developed according to the remodeling of trabecular bone. Secure fiber connection into the thickened trabecular bone developed by 16 postoperative weeks. On the basis of these results, in clinical settings, ruptured tendon ends should be attached to the remaining distal tendon end or to a cancellous surface; they should not be attached to a calcified fibrocartilage layer.