Helga Fritsch

Association between the mesenchymal compartment of uterovaginal organogenesis and local tumour spread in stage IB-IIB cervical carcinoma: a prospective study.

BACKGROUND Macroscopic, microscopic, and occult local tumour spread might be restricted to a permissive territory related to the morphogenesis of the tissue or organ from which the tumour originates. We aimed to define such a morphogenetic unit in Müllerian development, and to assess the role of total mesometrial resection in the treatment of patients with stage IB-IIB cervical carcinoma. METHODS We analysed uterovaginal development in serial sections of female human embryos and fetuses, and defined the distal Müllerian morphogenetic unit from the Müllerian mesenchyme. We assessed prospectively the histopathological and clinical findings from patients who underwent total mesometrial resection-modified surgery for stage IB-IIB cervical carcinoma that aims to remove the uterus, proximal vagina, and extracervical mesenchyme within the borders of the distal Müllerian morphogenetic unit. FINDINGS The spatial extension of the Müllerian mesenchyme, its vascularisation, and its innervation during early uterovaginal organogenesis determine a tissue territory that can be followed during fetal development and identified in women as a morphogenetic unit. 105 of 106 patients who had total mesometrial resection, 63 of whom were classed as high risk, had microscopically tumour-free resection margins (ie, R0). 48 (96%) of 50 patients had pelvic recurrence-free survival at 3 years (95% CI 92-100) without adjuvant radiotherapy. INTERPRETATION Radical en-bloc resection of a topographically defined anatomical territory derived from common precursor tissue leads to local tumour control, preservation of autonomic nerves, and a reduced need for adjuvant radiotherapy.

Rectocele: pathogenesis and surgical management

BackgroundRectocele is a common finding in patients with intractable evacuatory disorders. Although much rectocele surgery is conducted by gynecologists en passant with other forms of vaginal surgery, many reports lack appreciation of the importance of coincident anorectal symptoms, and do not report functional and clinical outcome data. The pathogenesis of rectocele is still controversial, as is the embryological and anatomical importance of the rectovaginal septum as well as recognizable defects in its integrity and its relevance in formal repair when rectocele is operated upon as the principal condition in patients with intractable evacuatory difficulty.DiscussionThe investigation and surgical management of rectocele is controversial given the relatively small numbers of operated patients in any single specialist unit and the relative lack of prospective data concerning functional outcome in operated cases. The imaging of rectocele patients is currently in a state of change, and the newer diagnostic modalities including dynamic magnetic resonance imaging frequently display a multiplicity of pelvic floor disorders. When surgery is indicated, coloproctologists most commonly utilize an endorectal defect-specific repair, but there are few controlled randomized data regarding outcome and response criteria of specific symptoms with particular surgical approaches. A Medline-based literature search was conducted for this review to assess the clinical results of defect-specific rectocele repairs using the endorectal, transvaginal, transperineal, or combined approaches. Only the studies are included that report both pre- and postoperative symptoms including constipation, evacuatory difficulty, pelvic pain, the impression of a pelvic mass, fecal incontinence, dyspareunia or the need for assisted digitation to aid defecation.ConclusionThe history of rectocele repair, its clinical and diagnostic features and the advantages, disadvantages and indications for the different surgical techniques are presented in this review. Suggested diagnostic and surgical therapeutic algorithms for management have been included. It is recommended that a multicenter controlled randomized trial comparing surgical approaches for symptomatic evacuatory dysfunction where rectocele is the principal abnormality should be conducted.

The Vascular Nature of Hemorrhoids

The arterial blood supply of the internal hemorrhoidal plexus is commonly believed to be associated with the pathogenesis of hemorrhoids. Ultrasound-supported proctoscopic techniques with Doppler-guided ligature of submucosal rectal arteries have been introduced for the therapy of hemorrhoids. The present investigation focuses on caliber and flow changes of the terminal branches of the superior rectal artery (SRA) supplying the corpus cavernosum recti (CCR) in patients with hemorrhoids. Forty-one outpatients (17 female, 24 male; mean age 48 years) with hemorrhoids of Goligher grades I-IV were compared with 17 healthy volunteers (nine female, eight male; mean age 29 years) by means of transperineal color Doppler ultrasound. The mean caliber of the arterial branches in the study group with hemorrhoids was 1.87±0.68 mm (range, 0.6 to 3.60 mm) and 0.92±0.15 mm (range, 0.6 to 1.2 mm) in the control group (P<0.001). The arterial blood flow was significantly higher in patients with hemorrhoids than in the control group (mean 33.9 vs. 11.9 cm/second, P<0.01). Our findings demonstrate that increased caliber and arterial blood flow of the terminal branches of the SRA are correlated with the appearance of hemorrhoids. We suggest that the hypervascularization of the anorectum contributes to the growth of hemorrhoids rather than being a consequence of hemorrhoids. Transperineal color Doppler ultrasound (CDUS) is an appropriate method to assess these findings in patients with hemorrhoids.

Structure, formation and role of cartilage canals in the developing bone

In the long bones, endochondral bone formation proceeds via the development of a diaphyseal primary ossification centre (POC) and an epiphyseal secondary ossification centre (SOC). The growth plate, the essential structure for longitudinal bone growth, is located between these two sites of ossification. Basically, endochondral bone development depends upon neovascularization, and the early generation of vascularized cartilage canals is an initial event, clearly preceding the formation of the SOC. These canals form a discrete network within the cartilaginous epiphysis giving rise to the formation of the marrow space followed by the establishment of the SOC. These processes require excavation of the provisional cartilaginous matrix which is eventually replaced by permanent bone matrix. In this review, we discuss the formation of the cartilage canals and the importance of their cells in the ossification process. Special attention is paid to the enzymes required in disintegration of the cartilaginous matrix which, in turn, will allow for the invasion of new vessels. Furthermore, we show that the mesenchymal cells of the cartilage canals express bone-relevant proteins and transform into osteocytes. We conclude that the canals are essential for normal epiphyseal bone development, the establishment of the growth plate and ultimately longitudinal growth of the bones.

The role of cartilage canals in endochondral and perichondral bone formation: are there similarities between these two processes?

We investigated the development of cartilage canals to clarify their function in the process of bone formation. Cartilage canals are tubes containing vessels that are found in the hyaline cartilage prior to the formation of a secondary ossification centre (SOC). Their exact role is still controversial and it is unclear whether they contribute to endochondral bone formation when an SOC appears. We examined the cartilage canals of the chicken femur in different developmental stages (E20, D2, 5, 7, 8, 10 and 13). To obtain a detailed picture of the cellular and molecular events within and around the canals the femur was investigated by means of three‐dimensional reconstruction, light microscopy, electron microscopy, histochemistry and immunohistochemistry [vascular endothelial growth factor (VEGF), type I and II collagen]. An SOC was visible for the first time on the last embryonic day (E20). Cartilage canals were an extension of the vascularized perichondrium and its mesenchymal stem cell layers into the hyaline cartilage. The canals formed a complex network within the epiphysis and some of them penetrated into the SOC were they ended blind. The growth of the canals into the SOC was promoted by VEGF. As the development progressed the SOC increased in size and adjacent canals were incorporated into it. The canals contained chondroclasts, which opened the lacunae of hypertrophic chondrocytes, and this was followed by invasion of mesenchymal cells into the empty lacunae and formation of an osteoid layer. In older stages this layer mineralized and increased in thickness by addition of further cells. Outside the SOC cartilage canals are surrounded by osteoid, which is formed by the process of perichondral bone formation. We conclude that cartilage canals contribute to both perichondral and endochondral bone formation and that osteoblasts have the same origin in both processes.

β-Cell Deficit in Obese Type 2 Diabetes, a Minor Role of β-Cell Dedifferentiation and Degranulation

CONTEXT Type 2 diabetes is characterized by a β-cell deficit and a progressive defect in β-cell function. It has been proposed that the deficit in β-cells may be due to β-cell degranulation and transdifferentiation to other endocrine cell types. OBJECTIVE The objective of the study was to establish the potential impact of β-cell dedifferentiation and transdifferentiation on β-cell deficit in type 2 diabetes and to consider the alternative that cells with an incomplete identity may be newly forming rather than dedifferentiated. DESIGN, SETTING, AND PARTICIPANTS Pancreata obtained at autopsy were evaluated from 14 nondiabetic and 13 type 2 diabetic individuals, from four fetal cases, and from 10 neonatal cases. RESULTS Whereas there was a slight increase in islet endocrine cells expressing no hormone in type 2 diabetes (0.11 ± 0.03 cells/islet vs 0.03 ± 0.01 cells/islet, P < .01), the impact on the β-cell deficit would be minimal. Furthermore, we established that the deficit in β-cells per islet cannot be accounted for by an increase in other endocrine cell types. The distribution of hormone negative endocrine cells in type 2 diabetes (most abundant in cells scattered in the exocrine pancreas) mirrors that in developing (embryo and neonatal) pancreas, implying that these may represent newly forming cells. CONCLUSIONS Therefore, although we concur that in type 2 diabetes there are endocrine cells with altered cell identity, this process does not account for the deficit in β-cells in type 2 diabetes but may reflect, in part, attempted β-cell regeneration.

Epithelial and Muscular Regionalization of the Human Developing Anorectum

In the past, interpretations of anorectal development were mainly based on analysis of serially sectioned embryos of various nonhuman species as well as some human specimens. A four‐dimensional view of the developmental situation in the human has never been established nor connected to recent findings obtained from newer molecular techniques. We, therefore, investigated human embryonic and fetal pelves by means of immunohistochemistry and in situ hybridization to elucidate differentiation and interaction of epithelial and mesenchymal layers of the anorectum. To emphasize spatial as well as sequential morphological development, we produced three‐dimensional reconstructions of the specimens at hand. Research conducted proved that the decisive steps of epithelial and muscular differentiation occur between the 7th and 9th week after conception. This study elucidates a biphasic epithelial “closure” in the anal canal and interactions between epithelium, smooth musculature, and skeletal musculature. Based on the results presented here, it is possible to describe the pathogenesis of two anorectal malformations: the imperforate anal membrane and the anal membrane stenosis. This study will now provide the basis for further research into developmental processes occurring before the ones examined. Anat Rec, 1449‐1458, 2007.

Bone development in the femoral epiphysis of mice: the role of cartilage canals and the fate of resting chondrocytes.

In mammals, the exact role of cartilage canals is still under discussion. Therefore, we studied their development in the distal femoral epiphysis of mice to define the importance of these canals. Various approaches were performed to examine the histological, cellular, and molecular events leading to bone formation. Cartilage canals started off as invaginations of the perichondrium at day (D) 5 after birth. At D 10, several small ossification nuclei originated around the canal branched endings. Finally, these nuclei coalesced and at D 18 a large secondary ossification centre (SOC) occupied the whole epiphysis. Cartilage canal cells expressed type I collagen, a major bone‐relevant protein. During canal formation, several resting chondrocytes immediately around the canals were active caspase 3 positive but others were freed into the canal cavity and appeared to remain viable. We suggest that cartilage canal cells belong to the bone lineage and, hence, they contribute to the formation of the bony epiphysis. Several resting chondrocytes are assigned to die but others, after freeing into the canal cavity, may differentiate into osteoblasts. Developmental Dynamics 236:2077–2088, 2007.

Ontogenetic anatomy of the distal vagina: Relevance for local tumor spread and implications for cancer surgery

OBJECTIVE We have suggested to base cancer surgery on ontogenetic anatomy and the compartment theory of tumor permeation in order to improve local tumor control and to lower treatment-related morbidity. Following the validation of this concept for the uterine cervix, proximal vagina and vulva, this study explores its applicability for the distal vagina. METHODS Serial transverse sections of female embryos and fetuses aged 8-17 weeks were assessed for the morphological changes in the region defined by the deep urogenital sinus-vaginal plate complex. Histopathological pattern analysis of local tumor spread was performed with carcinomas of the lower genital tract involving the distal vagina to test the compartment theory. RESULTS Ontogenetically, the female urethra, urethrovaginal septum, distal vagina and rectovaginal septum represent a morphogenetic unit derived from the deep urogenital sinus-vaginal plate complex. Herein, the posterior urethra, the urethrovaginal septum and the distal vagina form a distinct subcompartment differentiated from the dorsal wall of the urogenital sinus. From 150 consecutive patients with distal vaginectomy as part of their surgical treatment 26 carcinomas of the lower genital tract had infiltrated the distal vagina. All 22 tumors involving the ventral wall invaded the urethra/periurethral tissue. Of the five carcinomas involving the dorsal wall none invaded the rectum/mesorectum. CONCLUSION The pattern of local tumor permeation of lower genital tract cancer in the distal vagina can be consistently explained with ontogenetic anatomy and the compartment theory.

Localization of tartrate‐resistant acid phosphatase (TRAP), membrane type‐1 matrix metalloproteinases (MT1‐MMP) and macrophages during early endochondral bone formation

Endochondral bone formation, the process by which most parts of our skeleton evolve, leads to the establishment of the diaphyseal primary (POC) and epiphyseal secondary ossification centre (SOC) in long bones. An essential event for the development of the SOC is the early generation of vascularized cartilage canals that requires the proteolytic cleavage of the cartilaginous matrix. This in turn will allow the canals to grow into the epiphysis. In the present study we therefore initially investigated which enzymes and types of cells are involved in this process. We have chosen the mouse as an animal model and focused our studies on the distal part of the femur during early stages after birth. The formation of the cartilage canals was promoted by tartrate‐resistant acid phosphatase (TRAP) and membrane type‐1 matrix metalloproteinases (MT1‐MMP). In addition, macrophages and cells containing numerous lysosomes contributed to the establishment of the canals and enabled their further advancement into the epiphysis. As development continued, the SOC was formed, and in mice aged 10 days a distinct layer of type I collagen (= osteoid) was laid down onto the cartilage scaffold. The events leading to the establishment of the SOC were compared with those of the POC. Basically these processes were quite similar, and in both ossification centers, TRAP‐positive chondroclasts resorbed the cartilage matrix. However, occasionally co‐expression of TRAP and MT1‐MMP was noted in a small subpopulation of this cell type. Furthermore, numerous osteoblasts expressed MT1‐MMP from the start of endochondral ossification, whereas others did not. In osteocytogenesis, MT1‐MMP has been shown to be critical for the establishment of the cytoplasmic processes mediating the communication between osteocytes and bone‐lining cells. Considering the well‐known fact that not all osteoblasts transform into osteocytes, and in accordance with the present data, we suggest that MT1‐MMP is needed at the very beginning of osteocytogenesis and may additionally determine whether an osteoblast further differentiates into an osteocyte.