Adriamycin induces notochord hypertrophy with conservation of sonic hedgehog expression in abnormal ectopic notochord in the adriamycin rat model

BACKGROUND/PURPOSE

The Adriamycin rat model (ARM) is a well-established model of the Vertebral, Anorectal, Cardiac, Tracheoesophageal, Renal, Limb (VACTERL) association. The notochord, which expresses Sonic Hedgehog (Shh), has been found to be grossly malformed with ventral ectopic branches in the foregut region of embryos in the ARM. The authors designed this study to test the hypothesis that Shh-expressing ectopic notochord could contribute to an increased volume of notochord relative to total embryo volume, resulting in an increased concentration of Shh in the notochord of affected embryos.

METHODS

Adriamycin was administered intraperitoneally to rats on days 7 (E7), E8, and E9 of gestation and saline to control animals. Embryos recovered at E12 and E14 were examined immunohistochemically for Shh expression. Quantitative morphology using the Cavalieri technique was performed to determine embryo and notochord volume.

RESULTS

Embryos in both Adriamycin and control groups at E12 and E14 showed comparable levels of Shh expression in notochord at all locations. The percentage of notochord per embryo was significantly increased in Adriamycin embryos at E12 and E14 compared with equivalent controls.

CONCLUSIONS

These data suggest that Adriamycin induces notochord hypertrophy. With all regions of the notochord secreting Shh, this could result in a higher concentration gradient of Shh in close abnormal proximity to the foregut, possibly contributing to the malformations found in the VACTERL association.

Increased fibronectin expression in developing embryos is associated with abnormal notochord in the Adriamycin rat model

BACKGROUND

The VACTERL association is a spectrum of clinical conditions, including esophageal atresia (EA) and tracheoesophageal fistula (TEF), which affects approximately 1 in 5,000 live human births. The administration of intraperitoneal Adriamycin to pregnant rats reliably induces anomalies, such as EA and TEF, in their offspring, in what is known as the Adriamycin rat model (ARM). In affected embryos the presence of gross notochord abnormalities is commonly found, with typical features being ectopic ventral branches and adherence of the notochord to the foregut. Fibronectin (FN) is an extracellular matrix (ECM) glycoprotein present on most cell surfaces, in extracellular fluids and in plasma. FN is involved in various functions, including cell adhesion, cell motility and wound healing. Previous studies in rats have shown that a single dose of Adriamycin can produce an appreciable rise in FN levels in various organs such as kidney and heart. We hypothesised that Adriamycin administration could promote upregulation of FN expression contributing to increased gut-notochord adherence and the development of abnormal ventral notochordal branching in the ARM. This study was designed to investigate FN expression in ARM embryos.

METHODS

Adriamycin (1.75 mg/kg) was administered intraperitoneally to pregnant rats on days 7,8 and 9 of gestation (E7, E8 and E9 respectively). Control animals were given saline. Embryos recovered on E10-E14 were fixed, embedded in paraffin and sectioned. Immunohistochemistry using an anti-FN rabbit polyclonal antibody was performed.

RESULTS

FN expression in both Adriamycin and control embryos on E10, E11 and E12 was comparable. However, the levels of FN expression in Adriamycin embryos on E13 and E14 were significantly greater in embryos with abnormal notochords than in equivalent control embryos.

CONCLUSION

Adriamycin-induced increased expression of FN, in the ARM, may contribute to abnormal notochord development leading to the VACTERL association.

The timing of enteric neural crest cell colonisation of the chick embryo cloaca

Neural crest cell (NCC) migration and formation of the enteric nervous system (ENS) is an essential process in the development of the normal human gut. Abnormalities of the ENS lead to a number of neurochristopathies. In avian embryos, the cloaca acts as a common chamber into which gastrointestinal, urinary and genital tracts emerge. Previous studies have elucidated the specific timeframes at which NCCs reach the various regions of the developing chick gut but, to date, none have looked at NCC colonisation of the cloaca. The aim of our study was to investigate the exact timing of the appearance of NCCs in the cloaca of chick embryos. Chicken embryos were harvested on embryonic days (E) 8-12. Whole embryos were fixed, embedded in paraffin and sectioned. Fluorescent immunohistochemistry, using an anti-HNK-1/N-CAM monoclonal antibody, was performed and images were obtained by confocal microscopy. There was no evidence of NCCs in the cloaca of embryos from E8 to E11. Intense immunoreactivity to HNK-1 first appeared in the cloaca of E12 embryos, demonstrating a profuse circumferential colonisation by NCCs at this time. Our study is the first to show the exact timing of enteric NCC colonisation of the chick embryo cloaca. Further studies, involving quail-chick chimeras, are required to establish the true origin of cloacal NCCs and to establish the relationship between NCCs and persistent cloaca.

Childhood femoral hernia: a commonly misdiagnosed condition

Femoral hernia is a rare surgical entity in the paediatric age group. The diagnosis is still a challenging issue. The aim of our study was to review our experience with femoral hernias in children during the past 21 years. We reviewed retrospectively the medical records of all patients who underwent femoral hernia repair in our institution between 1980 and 2000. Thirty-eight children (20 females, 18 males) with the median age of 5.5 years underwent 42 femoral hernia repairs over a 21-year period. Correct preoperative diagnosis was obtained in 20 (53%) cases. Of the 18 (47%) misdiagnosed cases, 11 were found to have a femoral hernia at negative exploration for a clinically diagnosis of inguinal hernia and 7 were found to have a femoral hernia 1 week to 18 months (mean 2.5 months) post repair of a presumed inguinal hernia. Median follow-up time was 12 years (range, 6 months-22 years). Recurrent femoral hernias occurred in five (13%) patients 6 months to 3 years (mean 13.5 months) after initial hernia repair. This study shows that femoral hernia is still a commonly misdiagnosed condition. A correct preoperative diagnosis will lead to appropriate surgical management, thus avoiding unnecessary morbidity and preventing unnecessary reoperations.

Alterations in cholinergic and neuropeptide innervation of urinary bladder following partial bladder outlet obstruction

Posterior urethral valves (PUV) are the most common cause of bladder outlet obstruction (BOO) in infancy. Bladder instability, poor compliance and myogenic failure are responsible for the poor long-term prognosis in these patients. Previous studies have reported abundance of sensory neuropeptides, e.g. substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and acetylcholinesterase (AchE) nerves in the urinary bladder. We hypothesized that the functional changes in the bladder following BOO are due to alteration in cholinergic and sensory neuropeptide innervation. We therefore investigated cholinergic and sensory innervation of urinary bladder following BOO. Fifteen immature male guinea pigs (Hartley strain) 3-4 weeks old and weighing approximately 250 g. underwent placement of a silk ligature around the bladder neck to induce BOO. Controls included 5 sham-operated animals. The animals were killed 1, 2 and 4 weeks following obstruction, respectively. Whole-mount preparation and conventional sections of bladder wall were performed. AchE histochemistry, and single-label immunofluorescence histochemistry for SP, CGRP and VIP were utilized. Light microscopy and laser scanning confocal microscopy were used to assess the results. AchE staining showed marked increase in cholinergic innervation density within the suburothelial region following BOO. The staining for SP, CGRP and VIP demonstrated marked reduction in sensory nerve density within the suburothelial region 1 week following BOO and the lack of sensory innervation 4 weeks after BOO. The marked reduction in sensory innervation of the bladder and simultaneous increase in cholinergic innervation following BOO may lead to bladder instability and decrease in bladder compliance.

Adriamycin effects on the chick embryo

Adriamycin is an anthracycline, anti-neoplastic drug with known teratogenic effects on foetal rats in what is known as the Adriamycin rat model (ARM). This includes conditions similar to those in newborn humans, known collectively as the VACTERL association. This comprises vertebral (V), anorectal (A), cardiac (C), tracheoesophageal (TE), renal (R) and limb (L) anomalies. We designed this study to test the hypothesis that the administration of Adriamycin to chick embryos would cause similar anomalies to those in the VACTERL association seen in the ARM. Fertilized Ross eggs received Adriamycin doses from 2-50 microg into the air sac and from 0.9-6 microg into the albumin. Administration varied from day 0-3 (D(0-3)) with D(0) being the first day of incubation. Control eggs received saline. Embryos were incubated at 38 degrees C and a relative humidity of 70%. Embryos were recovered on D(14), paraffin-embedded and transverse sections studied for morphological abnormalities. In the air sac group ( n=142), 71% of Adriamycin embryos survived versus 86% of controls (n=29). In the albumin group (n=121), 42% of Adriamycin embryos survived versus 55% of controls (n=69). No embryos demonstrated anomalies consistent with the VACTERL association. Ventral defects affected 1% of surviving Adriamycin embryos versus 4% of controls in the air sac group. In the albumin group, 19.8% of surviving Adriamycin embryos had ventral defects compared to 15.7% of surviving controls. Anophthalmia affected 1% of the surviving embryos in the Adriamycin air sac group and 2% of the Adriamycin albumin group. No controls developed anophthalmia. Exencephaly affected 2% of the survivors in the Adriamycin air sac group but none of the albumin group or controls. The administration of Adriamycin to chick embryos in comparable doses and times to those used in the ARM does not appear to produce comparable effects in relation to developmental anomalies, such as the VACTERL association. Despite examining different administration routes and mimicking the ARM, by giving Adriamycin to embryos at gastrulation, we were unable to re-create the anomalies seen in the ARM.

Histopathological differences between recto-sigmoid Hirschsprung's disease and total colonic aganglionosis

Total colonic aganglionosis (TCA) is a severe form of ultra long Hirschsprung's disease with an incidence of 2 to 14% among all forms of intestinal aganglionosis. C-kit positive interstitial cells of Cajal (ICCs) are pacemaker cells that play a key role in the motility function of the bowel. The aim of this study was to compare the innervation and ICCs distribution in total colonic and recto-sigmoid HD. Full thickness colonic specimens were obtained from four children with TCA, ten with recto-sigmoid HD and four controls. Single immunohistochemistry using peripherin, neuronal nitric oxide synthase (nNOS) and c-kit antibody was performed and analysed in light microscopy. Additionally, whole-mount preparations were stained using anti c-kit immunohistochemistry and NADPH-diaphorase. In the ganglionic bowel of TCA, recto-sigmoid HD and control patients there was a strong nNOS and peripherin immunoreactivity (IR) in ganglia of myenteric and submucous plexus and in thin nerve fibres in the muscle layers. In the TCA there was weak or lack of nNOS IR in the sparse, short nerve trunks of the myenteric and submucous plexuses and muscle layers, whereas nNOS weakly positive nerve trunks were observed in the recto-sigmoid HD bowel. Peripherin IR was markedly reduced in the TCA specimens compared to recto-sigmoid HD. In the TCA specimens there was a lack of ICCs-MY in the smooth muscle layer in all the specimens, whereas in the recto-sigmoid aganglionic bowel ICCs-MY were markedly reduced. Whole-mount preparations showed lack of ICCs-MY and a markedly reduced number of NADPH-positive nerve trunks in TCA. Our findings demonstrate clear histopathological differences between rectosigmoid Hirschsprung's disease and total colonic aganglionosis.

Renal parenchymal damage in sibling vesicoureteric reflux

AIM

To compare the incidence of renal damage in siblings of patients with vesicoureteric reflux (VUR) who presented with a documented history of urinary tract infection (UTI) with asymptomatic siblings who were diagnosed with reflux during a screening programme for hereditary VUR.

METHODS

Medical and radiological records of the VUR patients (1990-2000) were examined for age, gender, mode of presentation, reflux grade and renal damage.

RESULTS

VUR was noted in 226 siblings (352 ureters) in 107 families. Of the 119 siblings of index patients, 64 were investigated for a documented UTI and 55 with no history of UTI were detected during screening for sibling reflux. Dimercaptosuccinic acid scan revealed reflux nephropathy in 25 (26%) of the 97 renal refluxing units (RRU) of siblings who presented with a UTI and in 6 (7%) of the 89 RRU of asymptomatic siblings who underwent screening voiding cystourethrography (p=0.0006). Mild renal damage was present in 20 (21%) RRU of siblings with UTI and in 2 (2%) RRU of the screened siblings (p < 0.001). Moderate to severe renal damage was present in 5 (5%) RRU of siblings with UTI and in 4 (4%) RRU of the screened siblings (p > 0.05).

CONCLUSION

This study demonstrated that the incidence of mild renal scarring was much higher in siblings who presented with UTI than in asymptomatic siblings. However, the incidence of moderate and severe renal scarring among asymptomatic siblings was comparable to that in siblings with VUR and UTI.

Effects of benzalkonium chloride treatment on the intramural innervation of the upper urinary tract

OBJECTIVE

To establish a model for investigating the pathophysiology of pelvi-ureteric junction (PUJ) obstruction, using benzalkonium chloride (BCI) treatment of the upper urinary tract of rabbits, and thus further elucidate the pathophysiology of PUJ obstruction, the most common urinary tract obstruction in children.

MATERIALS AND METHODS

Although various histological abnormalities have been described, PUJ obstruction may be functional. Defective innervation in PUJ has been suggested to be a major factor in the failure to transmit peristaltic waves across the PUJ. Previously established animal models of hydronephrosis deal mostly with surgical obstruction of the PUJ, which does not correlate with human congenital hydronephrosis. BCl has been used to ablate selectively neurones of the gastrointestinal myenteric plexus, which generated spastic segments with impaired peristalsis. Thus 12 rabbits were treated with BCl at the PUJ; the right upper urinary tract was dissected extraperitoneally and treated with a local application of 0.1% or 0.5% BCl (six each) for 15 min. The controls were four sham-operated animals treated with saline. The animals were assessed by intravenous urography (IVU) at 4 and 8 weeks after treatment, after which the animals were killed, the upper urinary tracts removed and whole-mounts prepared. Acetylcholinesterase (AChE) histochemistry, and neurofilament and tyrosine hydroxylase (TH) single-enzyme immunohistochemistry were used to detect the intrinsic innervation.

RESULTS

None of the animals had hydronephrosis on the IVU or at death. AChE histochemistry, TH and neurofilament immunohistochemistry showed no or very few nerve fibres within the BCl-treated PUJs in both (0.1% and 0.5%) groups. After saline treatment there was normal development of the neuronal plexus within the submucosal, muscular and adventitial layers of the upper urinary tract.

CONCLUSION

These results suggest that treatment with BCl is useful for ablating the intrinsic innervation in the upper urinary tract. Defective intrinsic innervation of the upper urinary tract did not lead to clinically or radiologically evident hydronephrosis. Further physiological studies using this model are needed to further elucidate the neuronal and myogenic influence on the development of PUJ obstruction.

Alterations in smooth muscle contractile and cytoskeleton proteins and interstitial cells of Cajal in megacystis microcolon intestinal hypoperistalsis syndrome

BACKGROUND/PURPOSE

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is characterized by decreased or absent peristalsis. Gastrointestinal motility depends on the enteric nervous system, smooth muscle cells (SMCs), and the interstitial cells of Cajal (ICCs). Contractile and cytoskeleton proteinase are important structural and functional components of SMCs. The aim of study was to examine the expression of contractile and cytoskeleton proteins in SMCs and distribution of ICCs in MMIHS bowel.

METHODS

Full-thickness bowel specimens were obtained from 4 infants with MMIHS and 4 controls. Specimens were processed as whole-mount preparations and frozen and paraffin sections. Combined staining of NADPH-d histochemistry/c-kit immunohistochemistry, single and double immunohistochemistry using alpha-smooth muscle actin (alpha-SMA), calponin (CALP), caldesmon (CALD), desmin (DES), protein gene product 9.5 (PGP 9.5) and c-kit antibodies were performed and examined using light and confocal scanning microscopy.

RESULTS

alpha-SMA, CALP, CALD, and DES immunoreactivity were reduced markedly in MMIHS bowel compared with controls. Combined NADPH/c-kit staining showed dense network of ICCs around myenteric plexus in MMIHS bowel. In contrast, the intramuscular ICCs either were absent or reduced in MMIHS bowel.

CONCLUSIONS

Marked reduction of contractile and cytoskeleton proteins in SMCs combined with reduced expression of intramuscular ICCs in the gut may be responsible for the motility dysfunction in MMIHS.

Pure alcohol injection of a congenital splenic cyst: a valid alternative?

Congenital splenic cysts are a rare entity. They are more frequent in children and young adults. They are true cysts, lined by epithelium with a typical trabeculation. Aspiration and injection with antibiotics (minocycline-tetracycline) or pure alcohol has been reported sparsely with variable results. The purpose of this case study is to report our experience with ultrasound (US)-guided aspiration and injection of a congenital splenic cyst, which, in our case, did not prove a viable alternative to surgical defenestration.

Mutation analysis of the RET gene in total intestinal aganglionosis by wave DNA fragment analysis system

BACKGROUND/PURPOSE

Total intestinal aganglionosis (TIA) extending from the duodenum to the rectum is the most rare form of Hirschprung's disease (HSCR) and usually is fatal. RET is the major gene associated with HSCR, and germline mutations of this gene account for up 50% of familial and up to 15 to 20% of sporadic cases in HSCR. The aim of this study was to investigate DNA variants in the RET gene in TIA patients using the WAVE DNA Fragment Analysis System.

METHODS

Genomic DNA was extracted from whole blood samples from 6 patients with TIA. Polymerase chain reaction (PCR) amplification of the 21 exons of RET was performed using published oligonucleotide primers. Heteroduplexes were followed by the WAVE DNA Fragment Analysis System with the DNASep cartridge.

RESULTS

WAVE system technology detected 16 variants in the RET gene in the 6 patients with TIA. Three patients had a significant mutation in exon 8, 11, and 15, respectively. Thirteen RET polymorphic variants also were detected in the 6 patients, with L746L variant in exon 13 occurring in 4 patients.

CONCLUSIONS

WAVE system technology is an efficient method for the detection of DNA sequence variants. Our findings suggest that not only RET mutations but also RET polymorphic variants may contribute to the occurrence of TIA.

Notochord anomalies in the adriamycin rat model: A morphologic and molecular basis for the VACTERL association

BACKGROUND/PURPOSE

The Adriamycin rat model (ARM) is a reliable model of the VACTERL association. The notochord is structurally abnormal in the region of the foregut, midgut, and hindgut in the ARM. The authors hypothesised that notochord anomalies allow ectopic expression of molecular signals in the developing embryo and thus lead to VACTERL malformations. This study was designed to investigate this hypothesis.

METHODS

Adriamycin (1.75 mg/kg) was administered intraperitoneally to pregnant rats on days 7, 8, and 9 of gestation. Control animals were given saline. Embryos were recovered on gestational days 10.5 to 14 at (1/2)-day intervals and at full term. The first group of embryos were embedded in resin, and sagittal sections stained with Toluidine blue were studied for morphologic abnormalities. The second group of embryos were examined using in situ hybridization for the expression of Sonic Hedgehog (Shh), a patterning gene implicated in the etiology of the VACTERL association.

RESULTS

Twenty-seven of the 28 (96.4%) full-term embryos showed VACTERL anomalies. Forty-five of the 50 (90%) experimental embryos (gestational days 10.5 to 14) showed notochord abnormalities. Abnormal ventral branches from the notochord toward the gut were a commonly observed abnormality. These were seen to impinge on the developing foregut, midgut, dorsal aorta, and kidney. In situ hybridization for Shh showed that these branches from the notochord expressed Shh in 66.6% of experimental embryos. This abnormal Shh expression was not seen in the control embryos.

CONCLUSIONS

Adriamycin diffusely induces altered notochord morphology in the rat embryo. The abnormal notochord morphology may allow ectopic expression of Sonic Hedgehog, and, thus, contribute to the malformations found in the VACTERL association.

Organized vitreous hemorrhage masquerading as an optic disc melanocytoma

PURPOSE

To present a case of organized vitreous hemorrhage masquerading an optic disc melanocytoma.

DISCUSSION

Optic nerve head melanocytoma is a benign slightly pigmented lesion arising from the edge of the disc presenting with a filed defect. Pigmented nature of the lesion in question due to presence of haemosidrin laden macrophages led a diagnostic dilemma. Trans vitreal biopsy confirmed the diagnosis.

CONCLUSIONS

Althought classical in presentation organized blood clots can masquerade a number of lesions including a melanocytoma as in the present scenario.