Biomedical subjects

P Puri

Publications and source records attributed to P Puri.

At least 163 records · Page 9Linked to original sources

PubMed1998

Phosphorylation and the actin cytoskeleton in defective newborn neutrophil chemotaxis.

We have investigated the role of actin polymerization in the defective polymorphonuclear neutrophil (PMN) chemotaxis of the human newborn, and its regulation by protein kinase C and by phosphatases 1 and 2A. Isolated PMNs from adult volunteers and healthy term newborns, i.e. umbilical cord blood, were studied. Chemotaxis was measured by a modified micropore filter assay, and actin polymerization was assessed by flow cytometry. Chemotaxis of newborn PMNs (median 18 microm, range 9-21 microm) was significantly reduced compared with adult PMNs (median 23 microm, range 17-34 microm) (p < 0.001). Coincubation with the protein kinase C inhibitor bisindolylmaleimide GF109203X, did not significantly alter chemotaxis, whereas coincubation with the phosphatase inhibitors calyculin A or okadaic acid caused parallel dose-dependent inhibition of chemotaxis in adult and newborn PMNs. Peak actin polymerization was reduced in newborn compared with adult PMNs in response to stimulation with formyl-methionyl-leucyl-phenylalanine and zymosan-activated serum, but was normal in response to phorbol myristate acetate. Prior incubation for 5 min with bisindolylmaleimide GF109203X, calyculin A, or okadaic acid caused no significant alterations in the actin polymerization response to stimulation with formyl-methionyl-leucyl-phenylalanine. We conclude that: 1) newborn PMNs have reduced actin polymerization in response to stimulation with chemotactic agents which act via cell surface receptors, but not with phorbol myristate acetate, which acts directly in the cytoplasm. This suggests that a defect in cell signal transduction may be an underlying factor in defective newborn PMN chemotaxis. 2) Phosphatase inhibitors strongly inhibit chemotaxis but not actin polymerization, therefore phosphatases 1 and 2A may be important regulators of PMN chemotaxis, but this regulation takes place either at a point distal to actin polymerization or via another pathway. 3) Similar results in adult and newborn PMNs suggest that this is not the site of the underlying defect in newborn PMN chemotaxis.

Actins↗

PubMed1998

NADPH diaphorase-containing nerve fibers and neurons in the myenteric plexus are resistant to postmortem changes: studies in Hirschsprung's disease and normal autopsy material.

OBJECTIVE: Nitric oxide is considered to be the most important messenger of inhibitory nonadrenergic, noncholinergic nerves in the enteric nervous system. Histochemical studies have shown that nitric oxide synthase is identical to reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase. Histochemical staining with NADPH diaphorase has been widely used to study nitrergic innervation of the gastrointestinal tract, but fresh tissue is considered a prerequisite for satisfactory results. The purposes of this study were to evaluate whether whole-mount specimens of human bowel obtained after death are suitable for histochemical staining with NADPH diaphorase and to compare the staining properties with those of specimens of resected bowel from patients with Hirschsprung's disease METHODS: Whole-mount preparations of the myenteric plexus were examined using NADPH diaphorase histochemical staining of bowel specimens obtained at autopsy from 18 pediatric subjects (31 specimens). Fresh tissue was also obtained from the colon of four patients with Hirschsprung's disease. The staining properties of postmortem specimens were assessed in relation to the postmortem time before fixation (<12 hours, 13-24 hours, or 25-48 hours) and were compared with those of specimens of ganglionic bowel from patients with Hirschsprung's disease. Specimens of aganglionic bowel were also stained and examined. RESULTS: Strong NADPH diaphorase staining was achieved in 26 of the 31 postmortem bowel specimens, including all specimens from patients who underwent autopsy 25 to 48 hours after death. Staining properties were similar to those obtained in ganglionic bowel specimens from patients with Hirschsprung's disease. In aganglionic bowel the normal myenteric plexus meshwork was absent and was replaced by weakly staining nerve fibers. CONCLUSION: Histochemical staining with NADPH diaphorase is a robust technique suitable for use with whole-mount preparations to demonstrate nitrergic innervation in motility disorders such as Hirshsprung's disease. The technique may be used with both fresh tissue and specimens obtained up to 48 hours after death.

Child↗

PubMed1997

Historical aspects of congenital diaphragmatic hernia

The first description diaphragmatic hernia appeared in 1575. In 1848, Bochdalek described congenital diaphragmatic hernia (CDH) occurring through a posterolateral defect. Successful surgical treatment of CDH in an infant was first performed in 1902, whereas the first neonate operated within 24 hours of life was reported in 1946. However, early surgery did not improve survival rates and the mortality was in the region of 50%. One reason for this was that more neonates underwent surgery who previously would have died without the repair of the CDH. Pulmonary hypoplasia and pulmonary hypertension were early recognised as important reasons for the high mortality rate. In recent years, an enormous effort has been made by research groups all over the world to describe the pathogenesis and pathophysiology of CDH, and apply these findings to clinical practice. Attempts have been made to define prognostic factors. Extracorporeal membrane oxygenation (ECMO) has produced encouraging results. Fetal surgical therapy remains an option in selected cases despite huge technical and ethical problems. Recently, several new therapeutic methods have been suggested, such as high frequency oscillatory ventilation, partial liquid ventilation, nitric oxide inhalation, surfactant therapy, and fetal tracheal ligation. However, more experience is required before the value of these approaches is clear. Despite these efforts, the mortality remains unacceptably high. The challenge for the future is to continue development of therapeutic approaches in order to improve survival of neonates with CDH.

Journal Article↗

PubMed1997

The RET proto-oncogene: a challenge to our understanding of disease pathogenesis.

RET gene alterations as disease-causative mutations have been demonstrated in five different disease entities: Hirschsprung's disease (HD); papillary thyroid carcinoma; and three types of inherited cancer syndromes: multiple endocrine neoplasia (MEN) 2A, MEN 2B, and familial medullary thyroid carcinoma. RET is expressed during embryogenesis in a temporally and spatially regulated manner, and plays an important role in the normal development of a variety of cell lineages, particularly in the establishment of the enteric nervous system. RET mutations observed in patients with HD are scattered along the gene without any hot spots, and possess a loss-of-function effect. RET mutations are detected with a higher incidence among familial cases (50%) than sporadic cases (15%-20%), and are more closely associated with long-segment HD than short-segment disease. In contrast to HD mutations, missense mutations observed in MEN 2 syndromes occur at specific codons, and gene rearrangements are characteristic in papillary thyroid carcinoma. Both missense mutations and gene rearrangements act in a dominant fashion, and cause constitutive phosphorylation on the tyrosine of RET and highly enhance RET kinase activity, leading to transforming or oncogenic activity.

Carcinoma, Papillary↗

PubMed1997

Mutations of the endothelin-B receptor and endothelin-3 genes in Hirschsprung's disease.

The endothelin-B receptor gene (EDNRB) and the endothelin-3 gene (EDN3) have recently been recognized as susceptibility genes for Hirschsprung's disease (HD). Novel EDNRB mutations have been detected in non-syndromic HD patients with heterozygous forms, and homozygous mutations of the EDNRB or the EDN3 genes have been reported in HD patients associated with type 2 Waardenburg syndrome. These observations confirm that impaired function of the endothelin-B receptor or endothelin-3 is involved in the aetiology of some human HD cases. EDNRB mutations appear to be associated with short-segment HD, in contrast to RET mutations, which are found mainly in long-segment aganglionosis.

Animals↗

PubMed1997

Altered messenger RNA expression of the neuronal nitric oxide synthase gene in infantile hypertrophic pyloric stenosis.

Nitric oxide (NO) has been described as a mediator of smooth muscle relaxation in the mammalian gastrointestinal tract. The enzyme neuronal nitric oxide synthase (NOS) catalyzes the formation of NO. We examined the expression of the neuronal NOS gene at the messenger RNA (mRNA) level in pyloric smooth-muscle biopsy specimens from six patients with infantile hypertrophic pyloric stenosis (IHPS) using a reverse transcription-polymerase chain reaction (RT-PCR) technique. For controls, smooth-muscle layer specimens of pylorus (n=3), ileum (n=2), and colon (n=2) were used. With 31 cycles of PCR reaction, control specimens revealed detectable signals for neuronal NOS mRNA. In contrast, signals of IHPS specimens were undetectable in five cases and very weak in one. By increasing the PCR to 37 cycles, detectable signals for neuronal NOS mRNA were observed in all IHPS specimens, but they were significantly weaker than those of controls. Since a low level of neuronal NOS mRNA may lead to impaired production of NO, our observations indicate that the excessively contracted, hypertrophied pyloric muscle in IHPS is a result of reduced expression of the neuronal NOS gene at the mRNA level.

Aged↗

PubMed1997

Active collagen synthesis by pulmonary arteries in pulmonary hypertension complicated by congenital diaphragmatic hernia.

The high mortality rate for patients with congenital diaphragmatic hernia (CDH) has been attributed to pulmonary hypoplasia and persistent pulmonary hypertension (PPH). The factors that cause vasoconstriction and vascular remodeling in PPH are not fully understood. Immunohistochemistry was performed on lung tissue obtained from postmortem CDH patients with pulmonary hypoplasia and PPH (n = 21) using the following antibodies: alpha smooth muscle-actin (ASMA), transforming growth factor-beta (TGF-beta), isoform specific (TGF-beta 1, -beta 2, -beta 3), and M-57. Normal lung tissues from age-matched sudden infant death syndrome patients (SIDS, n = 8) were obtained as controls. TGF-beta 3 immunoreactivity was observed in the adventitia but not in the media of pulmonary muscular arteries in patients with CDH. TGF-beta 1, -beta 2 immunoreactivity was either absent or faintly expressed in pulmonary arteries in CDH patients. No TGF-beta staining was observed in the pulmonary vasculature of SIDS patients. Newly synthesized procollagen (M-57) was easily detected in the media and adventitia in a large number of pulmonary arteries in all patients with CDH and in the neointima in two patients with long standing PPH. No M-57 staining was seen in the media of pulmonary arteries of the lungs of SIDS patients. These observations suggest a potential role of TGF-beta 3 but not TGF beta 1 or TGF beta 2 in pulmonary vascular remodeling and that smooth muscle cells in muscular pulmonary arteries are actively synthesizing collagen in patients with CDH complicated by PPH.

Antibodies, Monoclonal↗

PubMed1997

Use of synaptophysin polyclonal antibody for the rapid intraoperative immunohistochemical evaluation of functional bowel disorders.

Intraoperative biopsies are essential for accurately distinguishing between Hirschsprung's disease (HD) and intestinal neuronal dysplasia (IND), and vital for determining the extent of abnormal bowel for surgical correction. IND can be associated with HD and can be a cause of postoperative complications. Routine hematoxylin and eosin (H&E) staining is sometimes inadequate for identification of ganglion cells in biopsy specimens and can be the cause of confusion. The authors found synaptophysin (SY) to be more specific as an indicator of abnormal bowel innervation and invaluable for surgical planning. Twenty patients (15 with HD, 3 with IND, and 2 with IND complicating HD) received biopsies intraoperatively. There was markedly reduced immunoreactivity (ie, a decreased number of SY-positive synapses) seen in the intestinal smooth muscle layers of transitional, aganglionic, and IND bowel segments, whereas immunoreactive synapses were abundantly present in the smooth muscle layers of ganglionic colon in HD. SY immunoreactivity also showed ganglion cells and hypertrophic nerve trunks clearly. Rapid SY staining is a simple and consistently reliable method for the intraoperative evaluation of the distribution of synapses in myenteric plexuses as well as smooth muscle layers.

Antibodies↗

PubMed1997

Variant Hirschsprung's disease.

There are many clinical conditions that resemble Hirschsprung's disease despite the presence of ganglia cells on rectal biopsy. This group has focused its research interest into delineating variant Hirschsprung's disease based on specific histochemical, immunohistochemical, silver staining and electron microscopic studies. Between 1981 and 1996, full thickness rectal biopsy or resected surgical specimens from 66 patients with clinical symptoms suggesting Hirschsprung's disease were examined. Various functional bowel disorders diagnosed using different histological techniques included, intestinal neuronal dysplasia in 23, hypoganglionosis in 6, immature ganglia in 4, absence of argyrophil plexus in 3, internal sphincter achalasia in 15, and smooth muscle disorders in 15. The findings suggest the following: (1) Clinical conditions resembling Hirschsprung's disease despite the presence of ganglia cells on suction rectal biopsy can be diagnosed by providing an adequate biopsy and employing a variety of histological techniques. (2) Intestinal neuronal dysplasia (IND) is a distinct clinical entity that can be clearly proven histologically. Patients with IND not only have abnormalities of submucosal and myenteric plexuses but also defective innervation of the muscle and neuromuscular junction as well as the internal sphincter. (3) Internal sphincter achalasia, which is histologically characterized by nitregeric nerve depletion, can be diagnosed on anorectal manometry and successfully treated by internal sphincter myectomy. (4) The outcome of smooth muscle disorders is generally fatal. The need for surgical intervention should be weighed carefully and individualized because most operations have not been helpful and are probably not necessary.

Biopsy↗

PubMed1997

Altered mRNA expression of the neuronal nitric oxide synthase gene in Hirschsprung's disease.

Nitric oxide has been described as an inhibitory neurotransmitter to mediate smooth muscle relaxation in the mammalian gastrointestinal tract. The enzyme neuronal nitric oxide synthase (NOS) catalyzes the formation of NO. The authors examined the expression of neuronal NOS gene at the mRNA level in intestinal specimens from seven patients who had Hirschsprung's disease (HD) using reverse transcription polymerase chain reaction (RT-PCR) technique. With 35 cycles of PCR reaction, substantial signals of neuronal NOS mRNA were observed in the ganglionic bowel in all seven patients, whereas in the aganglionic bowel, neuronal NOS signals were weak in three patients, and undetectable in four patients. By increasing the PCR cycle to 40 cycles, barely detectable signals were observed in two of the latter four patients. Semiquantitative analysis in the three patients who showed weak signals with 35 cycles of PCR indicated that neuronal NOS mRNA expression in aganglionic bowel was decreased at least 1/50 to 1/100 of the level expressed in ganglionic bowel. Because absence or low level of expression of neuronal NOS mRNA may lead to impaired production of NO, our observations suggest that motility dysfunction in HD may be as a result of markedly decreased or no expression of the neuronal NOS gene at the mRNA level.

Base Sequence↗

PubMed1997

Age-related changes in innervation in hypertrophic pyloric stenosis.

BACKGROUND/PURPOSE: Recent reports have identified abnormal innervation of the circular muscle layer involving the fine intramuscular nerve fibers in hypertrophic pyloric stenous (HPS). HPS presenting after 3 months of age is rare. The aim of this study was to determine the distribution pattern of nerve fibers in the smooth muscle layers in HPS and correlate this with age at presentation. METHODS: Full-thickness pyloric muscle biopsy specimens were obtained from eight patients with HPS (five age 3 to 5 weeks, two age 3 months, and one age 7 months) and five controls with normal pylorus (age 5 days to 3 years). All specimens were stained with monoclonal antibody to the neural cell adhesion molecule (NCAM) using immunohistochemistry. RESULTS: There were many NCAM-positive nerve fibers in the circular and longitudinal muscle layers in the controls. No NCAM positive nerve fibers were seen in the circular or longitudinal muscle layers in the five cases of HPS in which the patients were less than 5 weeks old. In the two cases in which the patients were 3 months old, occasional NCAM-positive nerve fibers were seen in the circular layer, and moderate numbers of NCAM positive fibers were seen in the longitudinal muscle layers. Moderate numbers of NCAM-positive nerve fibers in the circular muscle layer and many NCAM positive nerve fibers in the longitudinal muscle layers were identified in the 7-month-old HPS patient. CONCLUSIONS: The data suggest that the pyloric muscle lacks innervation in the young HPS infant. Whereas, at 3 months of age the hypertrophied pyloric muscle is partially innervated, and at 7 months of age the pyloric muscle has practically normal innervation.

Age Factors↗

PubMed1997

Pulmonary artery structural changes in pulmonary hypertension complicating congenital diaphragmatic hernia.

Primary pulmonary hypertension is characterized by the presence of smooth muscle cells in nonmuscular compartments or segments of the vessel and the abnormal deposition of collagen in both the small muscular arteries and arterioles and the large elastic arteries. Victorian blue van Gieson staining and Immunostaining with anti-alpha smooth muscle actin (ASMA) were performed on lung tissues obtained during autopsy from 21 patients who had congenital diaphragmatic hernia (CDH) complicated by persistent pulmonary hypertension (PPH) and 10 control patients who died of sudden infant death syndrome (SIDS). The degree of medial thickening and adventitial thickening was measured in pulmonary arteries by image analysis and compared statistically. There was a significant increase in adventitial as well as medial thickness in arteries of all sizes in CDH patients compared with control patients (P < .001). The most striking increase occurred in arteries with an external diameter (ED) of less than 75 microns. Calculation of the areas of the various components in the wall of each vessel showed that for smaller vessels (< 75 microns ED), the area of the lumen was smaller and the area of the media and adventitia was larger in CDH patients compared with control patients (P < < .001). In vessels greater than 75 microns ED, the areas of media in CDH was the same as in controls and the area of adventitia in CDH was significantly larger than controls (P < .001). The present study provides evidence that an increase in adventitial thickness and adventitial area occurs in pulmonary arteries in CDH patients complicated by PPH. The structural changes in the adventitia of the pulmonary arteries may be an important factor in the development of PPH in patients with CDH.

Actins↗

PubMed1997

Mutation analysis of the RET, the endothelin-B receptor, and the endothelin-3 genes in sporadic cases of Hirschsprung's disease.

To date, three genes have been identified as susceptibility genes for Hirschsprung's disease (HSCR), the RET proto-oncogene, the endothelin-B receptor gene (EDNRB) and the endothelin-3 gene (EDN3). However, the question of whether these genes play a role in sporadically occurring HSCR has not been fully clarified. In this study, the authors performed mutation analysis of these three genes in 41 sporadic HSCR patients without any family history by using single-strand conformational polymorphism or denaturing gradient gel electrophoresis methods. Exon 2, 3, 5, 6, 12, 13, 15, and 17 of the RET gene, 7 exons of the EDNRB gene, and the region of the EDN3 gene including sequences corresponding to proteolytic cleavage sites and mature endothelin-3 were analysed. By direct sequencing, three causative RET mutations were confirmed; a Phe to Ser substitution at codon 174, a Cys to Tyr substitution at codon 197, and a point mutation at the splice acceptor site of intron 12, in patients with aganglionosis confined to the rectosigmoid colon, the transverse colon, and the total colon, respectively. In the EDNRB locus, two mutations were observed; a nonsense mutation of Trp to stop at codon 275, and a T insertion at nucleotide 878, in patients with aganglionosis confined to the rectosigmoid colon, and the descending colon, respectively. No mutation was detected in the EDN3 gene. Mutation rates were 7.3% in the RET and 5% in the EDNRB gene. Our data indicate that RET and EDNRB mutations have a role in the aetiology of some sporadically occurring HSCR. However, the low mutation rate of susceptibility genes in sporadically occurring HSCR suggests that other genes or environmental factors are involved in the development of the disease.

Endothelin-3↗

PubMed1997

Effect of major surgery on neutrophil chemotaxis and actin polymerization in neonates and children.

The authors have examined the effect of major surgery in neonates and older children on neutrophil (PMN) chemotaxis and on actin polymerization, an essential early step in PMN movement. Isolated PMNs from the following subjects were studied: healthy adult volunteers (n = 28), healthy newborns (n = 21), newborns undergoing major surgery (n = 7), and older infants and children undergoing major surgery (n = 14). Chemotaxis was measured by a micropore filter assay, and actin polymerization was measured by flow cytometry. Blood samples from surgical patients were obtained preoperatively, hourly during the procedure, immediately postoperatively, and 48 hours after surgery. Mean preoperative newborn PMN chemotaxis was similar to that of healthy newborn PMN, and mean preoperative PMN chemotaxis in children was similar to that of healthy adults. There were no significant alterations in PMN chemotaxis during or after major surgery in neonates or children. Peak PMN actin polymerization, after stimulation with formyl methionyl leucyl phenylalanine (FMLP) (10 nm), was significantly diminished in healthy neonates compared with adults (P < .005). Preoperative surgical neonates had similar peak PMN actin polymerization levels to those of healthy newborns, and older preoperative children had similar levels to adults. PMN actin polymerization did not significantly change during or after major surgery. Despite reductions in PMN chemotaxis and actin polymerization in healthy neonates, there is no further impairment of these PMN functions during or after major surgery. Our data suggest that PMN chemotactic function is resistant to the stress of uncomplicated major surgery in neonates and children.

Actins↗

PubMed1997

Morphological changes in the enteric nervous system of the transplanted fetal rat intestine.

In this study, enteric nervous system (ENS) of the fetal intestinal grafts was examined histopathologically. Forty-four rat fetal small intestines were transplanted syngenetically into the subcutaneous region of adult rats without vascular anastomosis. Thirty-two grafts survived. They were removed 2, 4, 6, and 8 weeks after transplantation and examined using (1) H&E staining, (2) AChE and NADPH-diaphorase histochemistry, and (3) protein gene product 9.5, S-100 protein, glial fibrillary acidic protein, tyrosine hydroxylase, nerve growth factor receptor, calcitonin gene-related peptide, neuropeptide Y, vasoactive intestinal peptide, somatostatin, and substance P immunohistochemistry. The grafts were compared with the intestines of 2-, 4-, 6- and 8-week-old control rats. ENS of the grafts was different from the controls as follows: (1) tyrosine hydroxylase and neuropeptide Y were markedly reduced but present, suggesting that the extrinsic innervation was present; (2) nitric oxide-producing neurons were well preserved in grafts; (3) hyperganglionosis in the myenteric plexus was seen in 6- and 8-week grafts; (4) AChE activity was increased in the circular muscle and in the lamina propria, (5) S-100 was increased in the lamina propria in 6- and 8-week grafts, (6) calcitonin gene-related peptide was increased in 6- and 8-week grafts, (7) nerve fibers in the muscle layers ran irregularly and disorderly, and (8) hypertrophy of smooth muscle layers. Our data show that although extrinsic as well as intrinsic innervation is present in the fetal intestinal grafts, there is hyperinnervation of the intrinsic nervous system and reduced innervation of the extrinsic ENS. These morphological changes in the ENS of the fetal intestinal grafts may result in motility dysfunction.

Animals↗

PubMed1997

Hepatic overexpression of MHC class II antigens and macrophage-associated antigens (CD68) in patients with biliary atresia of poor prognosis.

The pathogenesis of biliary atresia (BA) is still unknown. Progression to cirrhosis despite restoration of bile flow by successful portoenterostomy suggests that it is a progressive disease of the liver and biliary tree. Whether immunologic factors play any role in the development of this disease remains uncertain. Aberrant expression of major histocompatibility complex (MHC) Class II antigens of HLA-DR on hepatocytes and biliary epithelium is regarded as important in the progression of hepatocellular and biliary damage mediated by cytotoxic T cells. This study was undertaken to evaluate expression of MHC Class II antigen and macrophage-associated antigens (CD68) in liver of patients with biliary atresia to determine their prognostic usefulness and possible role in the pathogenesis of the disease. Liver biopsy specimens from infants with BA (n = 15), neonatal hepatitis (n = 3), and normal livers (n = 6) were studied using an indirect immunoperoxidase staining using antibodies against MHC Class II antigen and macrophage-associated antigens (CD68) as well as routine H&E and Masson's trichome stain. In patients with biliary atresia, the liver biopsy specimen was obtained at the time of Kasai portoenterostomy. Expression of HLA-DR antigens and CD68 antigens was either absent or minimal in normal liver biopsy specimens. There were a few HLA-DR antigens and a few CD68-positive cells around portal tracts in all patients with neonatal hepatitis and five of the seven biliary atresia patients with successful Kasai portoenterostomy. In contrast, there was strong expression of HLA-DR antigen in bile ductules, inflammatory cells, and adjacent damaged hepatocytes and marked CD68-positive macrophage infiltrate in the portal tracts as well as hepatic lobules in two patients with good prognosis and in all eight patients with bad prognosis. Hepatic expression of MHC Class II antigen and CD68 antigens correlated well with the severity of clinical course in patients with BA and may act as a prognostic factor in these patients.

Antigens, CD↗

PubMed1997

Altered RET gene mRNA expression in Hirschsprung's disease.

The RET proto-oncogene is a major cause of Hirschsprung's disease (HD) as demonstrated by the experimentally produced intestinal aganglionosis in mice with a null mutation of this gene and by the increased evidence of RET mutations in patients with HD. To evaluate the possible implication of the RET gene for the development of HD, we examined mRNA expression level of the RET gene in the bowel specimen of seven HD patients by using the reverse transcription-polymerase chain reaction technique. A significantly less intense signal for RET mRNA was found in the aganglionic bowel compared with the ganglionic bowel. In the hypoganglionic transitional zone, the RET mRNA level was higher than that of an aganglionic segment but lower than that observed in the ganglionic portion. In two patients where semiquantitative analysis was performed, the RET mRNA level in the aganglionic bowels was estimated to be approximately 1/500 of that in the ganglionic bowels. Because expression of RET mRNA plays an important role in establishing the enteric neuronal lineage, decreased RET mRNA expression in the aganglionic bowel may suggest maldevelopment of neural crest-derived cells in Hirschsprung's disease.

Colon↗

PubMed1997

Decreased bcl-2 expression in segmental renal dysplasia suggests a role in its morphogenesis.

OBJECTIVE: To evaluate the potential role of bcl-2 and apoptosis in the histogenesis of segmental renal dysplasia. MATERIALS AND METHODS: Surgically resected specimens of dysplastic upper poles of duplex kidneys were studied from 19 patients (mean age 3.4 years, range 2 months-9 years). Bcl-2 expression was detected immunohistochemically and apoptosis was investigated using the in situ end-labelling technique (ISEL). RESULTS: In the histologically normal areas of the specimens, bcl-2 expression was Intense in the proximal and distal convoluted tubules, moderate in Henle's loops and weak or absent in Bowman's capsule. In contrast, in the dysplastic areas there was no or markedly reduced expression of bcl-2 in mesenchyme and tubules. In the normal areas, apoptotic cells were extremely rare (0-1 per 25 high-power fields, HPFs), whereas in the dysplastic areas, some apoptotic cells were identified both in tubules (1-2 per 25 HPF) and in mesenchyme (5-8 per 25 HPF). CONCLUSIONS: As bcl-2 expression is required for normal kidney morphogenesis, finding no or markedly decreased expression of bcl-2 in the dysplastic areas may be related to the persistence of dysplastic fetal-type structures. Finding apoptosis adds further support to the concept that dysplasia represents arrested development at an early stage of morphogenesis before the period when bcl-2 assumes major importance.

Apoptosis↗