Spatiotemporal expression of Wnt5a during the development of the hindgut and anorectum in human embryos

Purpose  

The aim of the study was to determine the spatiotemporal expression of Wnt5a during hindgut and anorectum development in human embryos and to explore the possible role of Wnt5a during the morphogenesis of the human hindgut and anorectum.     

From cell death to embryo arrest: mathematical models of human preimplantation embryo development

Human preimplantation embryos exhibit high levels of apoptotic cells and high rates of developmental arrest during the first week in vitro. The relation between the two is unclear and difficult to determine by conventional experimental approaches, partly because of limited numbers of embryos. We apply a mixture of experiment and mathematical modeling to show that observed levels of cell death can be reconciled with the high levels of embryo arrest seen in the human only if the developmental competence of embryos is already established at the zygote stage, and environmental factors merely modulate this. This suggests that research on improving in vitro fertilization success rates should move from its current concentration on optimizing culture media to focus more on the generation of a healthy zygote and on understanding the mechanisms that cause chromosomal and other abnormalities during early cleavage stages.     

Defunctioning of the anorectum

BACKGROUND: Creating a defunctioning stoma for anorectal disease in patients in whom no resection or anastomosis is required appears eminently suited for laparoscopic techniques, with the intended advantages of early recovery, reduced pain, and avoidance of a laparotomy. OBJECTIVES: The study contained herein was undertaken to determine the feasibility of laparoscopic defunctioning stoma formation using a three-port technique (including one at the stoma site) and to compare initial results with a historical control group. METHODS: Duration of operation (anesthetic plus surgery), the time to tolerance of a liquid and then a solid diet, time to passage of flatus and feces, patient morphine requirements in the first 48 hours, and day of discharge were documented. RESULTS: Nineteen laparoscopic stomas were attempted (3 converted to open) and 23 open stomas were formed in the control group. The laparoscopic stoma group had lower morphine requirements (mean, 47.7vs. 89.9 mg;P<0.01), an earlier tolerance of both liquid (mean, 2.1vs. 3.7 days; P<0.01) and solid diets (mean, 3.6vs. 5.5 days;P<0.001), and an earlier time to passage of both flatus (mean, 2.2vs. 3.6 days;P<0.001) and feces (mean, 3.7vs. 5.6 days;P<0.001). Operating time was longer for the laparoscopic group (mean, 176vs. 104 minutes;P<0.001), whereas median time to discharge from hospital was shorter (median, 8vs. 11 days;P=0.014). Postoperative 30-day morbidity occurred in 1 of 19 laparoscopic group patients and 4 of 23 open group patients. CONCLUSIONS: In this select group of patients requiring defunctioning stoma only, laparoscopic surgery is feasible and safe and may have advantages over open procedures of less pain, earlier tolerance of diet, earlier return of bowel function, and a shorter median length of stay.     

Malignant melanoma of the anorectum

Summary Melanoma of the anorectum is a rare and highly malignant disease. Only 117 cases have been reported previous to this report in English medical literature. The clinicopathologic features of an additional 21 cases, encountered over a period of 25 years (1929 to 1954) at the Memorial Center, are described. Four more cases seen since 1955 are mentioned. These tumors can be mistaken easily for hemorrhoids or polyps and often their true nature is revealed by histologic examination. Is the preponderance of this tumor in Jewish and Italian people real or apparent? Often results of various methods of treatment are unpredictable, but in certain select cases which do not have distant metastases, preoperative external irradiation followed by abdominoperineal resection of the anorectum, or abdominoperineal resection of the anorectum without irradiation, seem to be the treatments of choice. The average survival time of patients in this group was 33 months. With the exception of one very unusual case, every patient in this series died of his original disease within five years, regardless of the type of therapy administered. Three other patients lived 44, 48 and 60 months.     

Melanotic adenocarcinoma of the anorectum

A variety of tumors, besides those formed by melanocytes, may contain melanin pigment. Most of them have originated from the neural crest. Epithelial tumors with melanosomes are very unusual. We report the case of a 76-year-old woman with rectal adenocarcinoma that invaded the intestine and vagina extensively. At the anorectal site, melanin pigment was found in the cytoplasm of the malignant neoplastic epithelial cells, and melanosomes were ultrastructurally confirmed at various developmental stages. Melanocytes with cytoplasmic processes spreading between neoplastic cells were also present as the apparent source of the pigment contained in the neoplastic cells.     

Malignant melanoma of the anorectum

Melanoma is a virulent tumor that can be widely disseminated and is genrally incurable even when the primary growth is small. Review of the cases of 34 patients with primary melanoma of the anorectum, with follow-up ranging from two to five years, suggests that improvement in survival depends on acute surgical awareness and aggressive surgical intervention. Read at the meeting of the American Society of Colon and Rectal Surgeons, Atlanta, Georgia, June 10 to 14, 1979.     

Short-chain fatty acids and water in the hindgut contents and feces of rats after hindgut bypass surgery

Omnivorous experimental animals with different levels of short-chain fatty acids in hindgut contents or in feces were established by surgical bypass of the colon and/or the cecum. Levels of short-chain fatty acids, amounts of luminal contents, and the water contents in these animals were compared. Regional variations in water absorption and retention of luminal contents are likely to be major factors in the regulation of hindgut functions.     

Flow cytometric analysis of human bone marrow: I. Normal erythroid development

Flow cytometry was used to identify maturational differences of erythroid lineage cells in normal human bone marrow by combining physical characteristics, the expression of multiple cell surface antigens, and nucleic acid content. Normal low-density bone marrow cells could be divided into four populations, based on forward and right-angle light scattering. Erythroid cells, at different maturational stages, were found in three of these four marrow subpopulations. The sequentially correlated expression of three cell surface markers--HLe-1, transferrin receptor, and glycophorin--allowed us to study erythroid maturation from the colony forming cell to the mature erythrocyte. HLe-1 was expressed on the earliest identifiable erythroid cells and was progressively lost as the cells matured. Transferrin receptor began to be expressed at the BFU-E stage and disappeared at the late reticulocyte stage. Transferrin receptor expression preceded glycophorin expression, the latter beginning on morphologically recognizable erythroid precursors just after the CFU-E stage. In contrast to both HLe-1 and transferrin receptor, which were progressively lost during the maturational process, once glycophorin had been maximally expressed on the cell surface, it remained at constant quantities to the mature erythrocyte stage. Although developing nucleated erythroid cells at approximately the normoblast stage had light-scattering properties similar to those of lymphoid cells, these two cell types could be resolved by cell surface antigen expression. Normoblasts were glycophorin positive and HLe negative, whereas lymphoid cells expressed HLe and either Leu 4, Leu 11, or Leu 12. Decreases in cellular nucleic acid content, corresponding first to the extrusion of the nucleus and second to the loss of reticulum, characterized the later stages of erythroid development. These characteristics and instrumentation can be used to purify erythroid cells at various developmental stages.     

Primary malignant lymphoma of the anorectum in homosexual men

Two homosexual men presented with primary malignant lymphomas of the anorectum. Each patient presented with a painful mass, diagnosed by biopsy and immunologic cell marker studies. One patient, who had a reversed T4/T8 cell ratio, developed a local relapse of the tumor 11 months after radiotherapy, andPneumocystis carinii pneumonia. The other patient, with a normal T4/T8 ratio, remained lymphoma-free and without evidence of opportunistic infection 25 months after combined chemotherapy and radiotherapy. Anorectal pathologic findings in homosexual men includes proctitis, inflammatory stricture, fissure, or anal warts. Malignant anorectal diseases, such as Kaposi's sarcoma, and cloacogenic or squamous cell carcinomas have been described in homosexual men. Primary malignant lymphoma of the anorectum is rate in both the homosexual and general populations.     

Diversion colitis and involution of the defunctioned anorectum.

To measure the effects of defunction in the anorectum, 12 patients (seven men and five women aged 59 (44-81) years) were studied after the Hartmann operation. The operation was for septic complications of diverticular disease in nine and sigmoid carcinoma in three patients. Physiology studies were undertaken 1 and 3 months after surgery, and diversion colitis was assessed endoscopically and by mucosal biopsy at 3 months. There was no change in anal sphincter function by three months. Proctometrogram studies, however, showed an appreciable decrease in rectal volume in all cases, by a mean of 35% of the 1 month volume. The maximum tolerable volume at 1 month was 157 (111-210) ml and at 3 months 87 (71-145) ml; p < 0.01. There was no change in rectal sensation or compliance. Erythema and granularity without gross erosions or ulceration were found at endoscopy. Histology showed abnormalities in all cases by 3 months. The characteristic features were of a chronic inflammatory cell infiltrate with surface exudate, microscopic erosions, and lymphoid follicular hyperplasia. Crypt abscesses were not a feature at this stage and there was no distortion of crypt architecture. After defunction the previously normal rectum is affected by diversion colitis which, at 3 months, is mild but has characteristics that distinguish the changes from those of inflammatory bowel disease. It is associated with progressive rectal stump involution.