| Hirschprung disease(HD)was primarily described by Harlald Hirschprung of Denmark. HD lies in the second in the inborn diseases of the gastrointestinal tract, about possessing 1 /2000-1/5000 of the living infants. HD was occurred 4-12 week of the embryo. The most reason was that the ganglion cell coulden't locate gatherly. According to the difference of the intestinal tract that has pathological changes, HD were divided the short, the long, the whole colon, and the whole digestive tract. The key feature was that the distant intestinal canal was absent or losable of the ganglion cell. The clinical manifestation of Allied Hirschsprung's disorder (HAD) was very similar with HD. But the pathological change was different f rom HD. It's manifestation were: ganglion cell–penia, ganglion cell-immature, ganglion cell-dystopia, ganglion cell–great. The diseas was ignored and incorrectly diagnosed of HD. It's disease incidence was about 20%-75% of the HD.Ret proto-oncogene was observed in the medullary thyroid carcinoma by Talabashi in 1985. It was a proto-oncogene which occurred in the course of DNA recombination activation. It has 80kb, 21 exons, divided five regions. Ret proteinum (tyrosine -kinase receptor) that the ret -coding product was a kind of superfamily transmembrane protein. It was generally expressed in the ganglion cell. The mechanism of the ret transducting signal was the receptor integrated with extrinsic factor of cell forming dimer to result in configuration's change, the receptor phosphorylating itself, activating tyrosine–kinase in the intramembrane, at the same time the the tyrosine of the substrate phosphorylated, thus the signal entered the cell, transmiting to the effector, transducer, adaptor, accordingly effecting the physiological functions and the growth and development of the cell. That the gene mutated would lead to the abnormality of the migration and differentiation of the neural crest cell, initiating according diseases.Nervous system type NOS (nNOS) is the rate-limiting enzyme to synthetizing NO. However NO is the important transmitter and mediater belonging to rejection capability NANC.This kind of transmitter have important mediating contribution to the movement of stomach intestine. The neuron and neurofibra of nNOS released the NO to the smooth muscle, activating Gua-cyclase(GC), raising the density of cGMP ,degrading the the density of Ca+ or the sensitivity to Ca+ of muscle cells, leading to smooth muscle relaxation. Moreover, the independent contraction of the colon circular muscle (machinery slow wave) was partly controlled by electrophysiology initiated by the pacemake in submucosa, submucosa was dominated by NO nerve. Therefore the expression abnormity would initiate the according diseases.The experiment used the immunity- histochemistry. We observed the expression of Ret, nNOS in the colon of HD, HAD and the normal, in order to invest the role of Ret, nNOS in neural development. Meanwhile we can comprehend the relationship and distinction between HD and HAD.Our experiment have the HD and HAD models from Tongji Hospital, which were diagnosised as HD and HAD after operation. There were 15 cases of HD, 12 male cases, 3 female cases; there were 11 caese HAD, 8 male cases, 3 female cases. The ages were between 1 muoth and 9 years. We collected stenotic and dilated segment of bowels from every case. Each paraffin block chiped three slices continuously. The thickness was 6um. At the same time, we selected 10 normal cases as the control. The ages were between 3 years and 8 years. We used the monoclone antibody, adopted SABC immunity-histochemistry. We observed the relationship and difference between the two diseases from two aspects. The first part we compared the expression of Ret+ cell in the different segment of the three groups. Each group took five slices. We randomly selected five campus visualis under the microscope of 200 times from every slice. Then we counted and statisticsed the Ret+ cell. The second part we observed the expression of the neurotransmitter of nNOS. We took five campus visualis in the different segment of the three groups. The images were imported to computer, dealed by cell measurement routine of HMIAS-2000, removaled gray scale of background. We have statistical analysis to the integral photodensity of the brown-yellow reflexing products, comparing the difference of the three groups in the expression of nNOS. Thereby we can offer objective evidence to the diagnosis of HD and HAD.The results of the experiment:①Ret proteinum was positive in the dilated segment of bowels of HD, HAD and the control group (P>0.05). It was almostly negative in the stenotic segment of HD bowels. Very few positive cells can be seen in the stenotic segment of HD bowels; there were Ret+ cells in the in the stenotic segment of HAD bowels, what's more we could see huge positive cells. It was statistical significance in the stenotic segment bowels between the HD and HAD; and between the stenotic segment bowels of HD and the normal (P<0.001).②nNOS was positive in the dilated segment of bowels of HD,HAD and the control group (P >0.05). It was almostly negative in the stenotic segment of HD bowels. Very few positive cells can be seen in the stenotic segment of HD bowels; there were nNOS cells in the in the stenotic segment of HAD bowels, what's more we occasionally could see huge nervous plexus containing some positive cells. It was statistical significance in the stenotic segment bowels between the HD and HAD; and between the stenotic segment bowels of HD and the normal (P <0.001).The results of the experiment hinted that the pathogenesis of HD and HAD was different. The evidence were as follows:①Ret proteinum has important roles in the migration,differentiation,development. Its abnormal express would cause HD. But Ret proteinum has little with HAD. Furthermore, the gene had certified many times that HAD had nothing with the mutation of Ret.②The pathogenesis of HD had something with the nNOS decrease; however the pathogenesis of HAD was possiblely the neurotransmitter disorder caused by dys-environment during the course of ENS development.
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