OS08.6.A Novel role of ARF4-mediated retrograde trafficking as a driver of chemoresistance in GBM

Background

Glioblastoma (GBM) is the most common type of adult malignant brain tumor, with a median survival of only 21 months. This is partly due to the high rate of resistance to conventional therapy, including temozolomide (TMZ), leading to recurrence rates close to 100%. To identify the unknown genes driving the development of this resistance, we performed a genome-wide CRISPR knockout screen comparing a DMSO-treated population with a TMZ-treated population over 14 days. Results showed substantial enrichment of ~200 novel genes, including a previously unstudied gene ARF4—involved in retrograde trafficking to the nucleus. Here, we set out to characterize the mechanism by which ARF4 may be acting to promote chemoresistance.

Material and Methods

A whole-genome CRISPR-Cas9 sensitivity screen as well as a variety of in vitro and in vivo experiments, such as live-cell imaging, cell viability assays, and western blotting were conducted.

Results

Initial investigation into ARF4 showed significant elevations in expression at RNA and protein levels (p<0.05) in recurrent patient tumors, as well as a significant survival benefit in patient datasets when downregulated (p<0.05). Knocking out ARF4 resulted in significantly heightened sensitivity to TMZ in multiple GBM patient-derived xenograft lines and extended survival compared to the controls (p<0.01) in vivo. Further investigation via live-cell imaging of transferrin receptors, a retrograde transport marker, revealed that ARF4-knockdowns significantly inhibited retrograde trafficking, while ARF4-overexpressions resulted in an untenable increase in retrograde trafficking in vitro. This effect was also seen in TMZ-treated cells, which displayed enhanced trafficking dynamics, suggesting that ARF4-mediated retrograde trafficking is elevated during therapy to drive nuclear localization of key chemoresistance-promoting factors. We then performed an unbiased proteomics screen to identify which genes were being uniquely transported to the nucleus as a product of ARF4-mediated retrograde trafficking, which revealed enrichment of the EGFR signaling pathway in particular. Validation experiments confirmed a decrease in EGFR trafficking and nuclear EGFR expression in ARF4-knockdowns and an increase in EGFR trafficking and nuclear EGFR expression in ARF4-overexpression and TMZ-treated GBM cells. Furthermore, nuclear DNA-PK, a DNA repair protein known to be transcriptionally activated by EGFR, was similarly found to be downregulated in ARF4-knockdown conditions and elevated in ARF4-overexpression and TMZ-treated conditions.

Conclusion: Here, we show that ARF4 may be responsible for promoting chemoresistance through altered retrograde trafficking of EGFR specifically. Thus, our study has yielded a promising and novel therapeutic target for GBM, a disease desperately in need of new therapeutic strategies.

1011 CONTINUUM OF GERIATRIC CARE FOR OLDER ADULTS WITH DUAL SENSORY LOSS DURING THE COVID-19 PANDEMIC IN CANADA: LESSONS LEARNED

Introduction

Around 1.1 million older Canadians live with combined hearing and vision impairment (dual sensory loss/DSL). Evidence highlights that they are at a high risk of cognitive impairment, functional decline, social isolation, falls, depression, and mortality. Compared to their non-DSL peers, older adults with DSL experience various challenges in accessing healthcare, which were exacerbated during the COVID-19 pandemic. This study aimed to explore the continuum of geriatric care for older adults with DSL by integrating their perspectives, those of caregivers who accompany them on healthcare visits, and their healthcare providers in Canada during the pandemic.

Method

We conducted a qualitative study with 32 older Canadians with DSL and their caregivers, and an online survey with 228 healthcare providers across the country. Qualitative interviews were audio-recorded using Zoom and transcribed verbatim, while the survey data were collected using Lime Survey. Thematic analysis was used to analyse qualitative data, whereas descriptive statistics were used for quantitative survey data.

Results

The findings highlighted the gaps in the continuum of care for this population. The reported gaps were lack of training on DSL among healthcare providers, lack of time and comfort to go beyond one’s specialty, lack or limited support to overcome communication challenges while providing care to older adults with DSL, difficulty in using technologies for virtual/telehealth, presence of comorbidities such as cognitive impairment, and restrictions in caregiver accompaniment during the pandemic.

Conclusion

Our findings indicate that the continuum of care for this group is negatively affected due to the pandemic, in a disproportionate manner, and structural barriers are experienced by older adults with DSL and their caregivers for access to care. To ensure effective care, healthcare professionals need training on DSL-specific accessibility and communication. A collaborative, cross-disciplinary geriatric care approach with the active involvement of essential care partners is an utmost need.

Comparative evaluation of paired blood culture (aerobic/aerobic) and single blood culture, along with clinical importance in catheter versus peripheral line at a tertiary care hospital

PURPOSE

Paired blood culture (PBC) is uncommon practice in hospitals in India, leading to delayed and inadequate diagnosis. Also contamination remains a critical determinant in hampering the definitive diagnosis.

OBJECTIVES

To establish the need of PBC over single blood culture (SBC) along with the degree of contamination, this comparative retrospective study was initiated.

MATERIALS AND METHODS

We processed 2553 PBC and 4350 SBC in BacT/ALERT 3D (bioMerieux) between October 2010 and June 2011. The positive cultures were identified in VITEK 2 Compact (bioMerieux). True positivity and contaminants were also analyzed in 486 samples received from catheter and peripheral line.

RESULTS

Out of 2553 PBC samples, positivity was seen in 350 (13.70%). In 4350 SBC samples, positivity was seen in 200 samples (4.59%). In PBC true pathogens were 267 (10.45%) and contaminants were 83 (3.25%), whereas in SBC 153 (3.51%) were true positives and contaminants were 47 (1.08%). Most of the blood cultures (99.27 %) grew within 72 h and 95.8% were isolated within 48 h. In 486 PBCs received from catheter/periphery (one each), catheter positivity was found in 85 (true positives were 48, false positives 37). In peripheral samples true positives were 50 and false positives were 8.

CONCLUSION

Significantly higher positive rates were seen in PBCs compared with SBCs. Automated blood culture and identification methods significantly reduced the time required for processing of samples and also facilitated yield of diverse/rare organisms. Blood culture from catheter line had higher false positives than peripheral blood culture. Thus every positive result from a catheter must be correlated with clinical findings and requires further confirmation.

Neuromedin U: physiology, pharmacology and therapeutic potential

Neuromedin U (NmU), a multifunctional neuropeptide, belongs to a family of neuropeptides, the neuromedins. It is ubiquitously distributed with highest levels found in the gastrointestinal tract and pituitary. The conservation of structural elements of NmU across species, the widespread distribution of NmU and its receptors throughout the body point to a fundamental role in key physiological processes. Two G protein coupled receptors for NmU have been cloned NmU R1 and NmU R2. NmU R1 is expressed pre-dominantly in the periphery especially the gastrointestinal tract whereas NmU R2 is expressed pre-dominantly in the central nervous system. Current evidence suggests a role of NmU in pain, in regulation of feeding and energy homeostasis, stress, cancer, immune mediated inflammatory diseases like asthma, inflammatory diseases, maintaining the biological clock, in the regulation of smooth muscle contraction in the gastrointestinal and genitourinary tract, and in the control of blood flow and blood pressure. With the development of drugs selectively acting on receptors and knockout animal models, exact pathophysiological roles of NmU will become clearer.

Protein kinase C beta inhibitors: a new therapeutic target for diabetic nephropathy and vascular complications

Diabetic nephropathy (DN) has emerged as the major causative pathology in patients entering end-stage renal disease (ESRD) worldwide and it is responsible for 30-40% of all ESRD cases. Treatments for DN are centered on control of hyperglycemia and blood pressure control. However, current therapeutic regimens have not yet provided satisfactory prevention from the onset of DN. Protein kinase C (PKC) is an intracellular signaling molecule and activation of it plays an important role in the development of diabetic complications. In numerous experimental and clinical studies, inhibition of PKC (LY333531) has been shown to delay/halt the progression of diabetic complications. Presently, the drug is submitted in USA-FDA for new drug application in moderate to severe diabetic retinopathy. This review selectively discusses the role of PKC in DN and therapeutic effects produced by PKC inhibitors in DN. The role of PKC inhibitor in other diabetic complications is also discussed.

Therapeutic potential of cannabinoid receptor ligands: current status

There are at least two types of cannabinoid receptors, CB1 also named CNR1 and CB2 also named CNR2, both coupled to G proteins. CB1 receptors exist primarily on central and peripheral neurons. CB2 receptors are present mainly on immune cells. Endogenous agonists for cannabinoid receptors (endocannabinoids) have also been discovered, the most important being arachidonoyl ethanolamide (anandamide), 2-arachidonoyl glycerol (2-AG), and 2-archidonyl glyceryl ether. Following their release, endocannabinoids are removed from the extracellular space and then degraded by intracellular enzymic hydrolysis. CB1/CB2 agonists are already used clinically as antiemetic or to stimulate appetite. Potential therapeutic uses of cannabinoid receptor agonists include the management of multiple sclerosis, spinal cord injury, pain, inflammatory disorders, glaucoma, bronchial asthma, vasodilatation that accompanies advanced cirrhosis, and cancer.

The adjuvant effect of melatonin on anaesthesia induced by thiopental sodium, ketamine and ether in rats

This study evaluated the anesthetic effects of thiopental sodium, ketamine, and ether with concurrent administration of melatonin. The loss of righting reflex was taken to assess the onset of anesthesia. Melatonin (20 mg/kg, p.o.) potentiated the anesthetic effects of thiopental sodium (20 mg/kg, i.v.) and ketamine (50 mg/kg, i.p.). Melatonin pretreatment caused rapid onset of anesthesia after ketamine and thiopental sodium administration while the duration of action of these agents was prolonged. Melatonin failed to alter anesthetic effects of ether (2 mg/kg by open method) in rats. This study suggests that melatonin modulate mechanisms involved in induction of thiopental sodium and ketamine anesthesia.

Pseudoexstrophy in a female child

A six-year-old female patient presenting with a swelling in the infraumbilical part of the abdomen, bulging out on straining, was diagnosed to have pseudoexstrophy bladder. The urinary tract was normal. The patient had bifid clitoris. There was no other associated malformation. Surgical repair of abdominal wall defect was done successfully. A new classification of exstrophy variants is proposed.

Colostomy in neonates with a massively distended abdomen due to an imperforate anus

A simple technique of intraoperative decompression and colostomy in neonates with a massively distended abdomen is described. With this technique, the handling of distended bowel becomes easier and peritoneal contamination by meconeum is also prevented.

Choledochal cyst: a 10-year experience

A retrospective study of 11 cases of choledochal cyst over a period of 10 years is presented. There were 8 females and 3 males in a ratio of 2.67:1. The classical triad of jaundice, mass and abdominal pain was seen in none of our patients. Ultrasonography was diagnostic in 9 out of 11 (80%) patients. Surgical procedures performed were, complete excision of the cyst with Roux en Y hepaticojejunostomy (nine cases), internal drainage of the cyst (one case) and excision of the extrahepatic cyst with Roux en Y hepaticojejunostomy in one case of Type IV choledochal cyst. One patient died in the immediate postoperative period. Others have remained well upto 10 years follow-up. We recommend total cyst excision with hepaticojejunostomy as the treatment of choice.

Neonatal intestinal obstruction with isolated levocardia

An unusual case of isolated levocardia, duodenal obstruction, and malrotation with volvulus is reported. Three cases of situs inversus abdominus with malrotation with volvulus have been reported to date. The current case is the fourth case and only the second survivor in the series. In cases of situs inversus abdominus, because of inversion of viscera, the volvulus may occur in an anticlockwise direction and, thus, should be derotated in a clockwise direction.

Hypergammaglobulinemic purpura of Waldenström: report of 3 cases with a short review

Benign hypergammaglobulinemic purpura of Waldenström (HGPW) is an uncommon cause of non-thrombocytopaenic purpura that may create diagnostic difficulties. The presence of constitutional symptoms associated with prominent immunological abnormalities may raise alarm, leading to extensive and often unnecessary investigations. This report describes 3 young women with HGPW. Clinical features were characterised by recurrent episodes of bilateral asymmetrical palpable purpuric lesions on the lower extremities that were precipitated by a prolonged increase in hydrostatic pressure (e.g. prolonged standing, tight stockings etc.) associated with constitutional features. In one patient the condition was secondary to Sjögren's syndrome with type IV renal tubular acidosis. Laboratory abnormalities included a persistently elevated erythrocyte sedimentation rate, marked polyclonal hypergammaglobulinemia, and high titers of rheumatoid factor and anti-nuclear antibody of the anti-SSA (anti-Ro)/anti-SSB(anti-La) subsets. This topic is reviewed briefly with the emphasis that in its 'primary' form this condition could be considered a 'benign' systemic immunoinflammatory disease that requires neither extensive investigations nor any aggressive form of therapy. Greater awareness of HGPW may increase the frequency of its diagnosis, especially in the patient group with non-thrombocytopenic purpura or the so-called cutaneous vasculitic syndromes with 'palpable purpura'.

Accessory scrotum

A 2-year-old male with a perineal swelling, covered with normal skin without any rugosities, was diagnosed as having an accessory scrotum on histopathology. There was no other congenital anomaly. The case is reported due to its rarity and unique clinical picture.

Cystic lymphangioma with special reference to rare sites

A 10 year retrospective study of 45 cases of cystic lymphangioma (CL) in children is presented. There were 25 females and 20 males. Age ranged from 6 months to 8 years. Common sites were involved in 38 and rare sites in 7 patients. Rare sites were--gluteal region (1), pelvis (1), retroperitoneum (1), mesentery (2), inguinal region (1) and inguinoscrotal region (1). The clinical presentation included sudden increase in size (25), lump abdomen (3), gluteal abscess (1), abdominal distension (1) and inguinal swelling (2). Diagnosis was established preoperatively in 38 cases, and after surgery and histopathology in 7 cases. Near total or subtotal excision was carried out in all cases. Facial nerve palsy (1) and recurrence (2) were the complications of surgery. The study is presented to highlight the occurrence of the cystic lymphangioma at rare sites to avoid diagnostic errors and unnecessary mutilating surgery.

Multiple neurilemmomas of the penis

A 10-year-old male with multiple small swellings over the shaft of the penis for 2 years was found to have multiple neurilemmomas on histopathologic examination. The case is reported in view of the extreme rarity of the entity.

Post traumatic bile ascites

A 4 year old girl with progressive distension of abdomen and previous history of blunt abdominal trauma was found to have bile ascites due to left hepatic duct (LDH) injury. The management with a brief review of literature is discussed below.

Caudal duplication--a case report

Caudal duplication is a rare entity due to incomplete separation of mono-ovular twins. It is usually associated with various congenital malformations involving mainly the genitourinary and gastrointestinal tracts. We report such a case operated upon successfully in which there was no other associated anomaly.

Hepatitis C virus infection in sporadic fulminant viral hepatitis in North India: cause or co-factor?

INTRODUCTION

The role of hepatitis C virus (HCV) infection in fulminant hepatitis (FH) is poorly understood and the available data are conflicting. We have examined the aetiological role of HCV in 50 consecutive patients with sporadic FH by employing serology and reverse transcription-polymerase chain reaction (RT-PCR).

MATERIALS AND METHODS

A total of 50 consecutive patients with sporadic FH were included. After an initial clinical and biochemical assessment, tests were performed for detection of HBsAg, IgM anti-HBc, IgM anti-HAV, IgM anti-HEV and anti-HCV. RT-PCR was carried out for detection of HCV RNA in sera of all the patients and in post mortem liver biopsy tissue of 20 subjects, using primers selected from the conserved 5' non-coding region of the HCV genome.

RESULTS

Hepatitis E virus (HEV) was found to be the most common viral infection (21/50; 42%) followed by HBV (14/50; 28%), HCV (7/50; 14%) and HAV (2/50; 4%). No viral markers could be detected in nine patients (18%) and multiple infections were seen in seven (14%). Of the seven subjects who tested positive for HCV-related markers, two had both anti-HCV and HCV RNA, three had HCV RNA alone and the remaining two had anti-HCV alone. Interestingly, all the HCV-infected subjects were co-infected with other hepatotropic viruses and the most common co-infecting agent was found to be HBV (5/7). Liver tissue was available in 20 cases and HCV RNA was detected in three of them. All of these patients were also positive for the viral genome in their serum samples. Comparison of the biological attributes of HCV-positive and HCV-negative cases revealed that haemorrhagic symptomatology (haematemesis, melaena and purpurae) was significantly more common, prothrombin time more deranged and mortality was much higher in the former group. The overall mortality was 68% and the most common cause of death was cerebral oedema (70.6%). No significant correlation was observed between mortality and the duration of the icterus-encephalopathy interval. The study included a total of 21 pregnant females; HEV infection was found to be significantly greater in this group and was associated with a higher mortality rate.

CONCLUSIONS

The results clearly suggest that HCV is not an important aetiological factor for FH in North India. However, it may act as a co-factor in the development of FH leading to a higher mortality. HEV appears to contribute substantially to the causation of sporadic FH in India and advanced stage pregnancy is a potential risk factor for HEV-induced FH and high rate of mortality. Our study also suggests that the length of the icterus-encephalopathy period may not have significant prognostic implications in Indian patients with FH.

The HNF-3alpha transcription factor is a primary target for retinoic acid action

We have previously demonstrated that gene expression of the hepatocyte nuclear factor 3alpha (HNF-3alpha) transcription factor is activated during retinoic-acid-induced differentiation of F9 embryonal carcinoma cells (A. Jacob et al. (1994). Nucleic Acids Res. 22, 2126-2133). We have extended these studies and now show that HNF-3alpha mRNA is induced approximately 6 h after addition of retinoic acid to the cells, peaks at 1 day postdifferentiation, and then declines to undetectable levels. Furthermore, HNF-3alpha induction occurs in the absence of de novo protein synthesis, suggesting that it is a primary target for retinoic acid action. In order to corroborate this hypothesis, we have mapped the cis-acting HNF-3alpha promoter site that mediates the retinoic acid response. DNA sequence analysis indicates that the HNF-3alpha promoter contains an authentic retinoic acid response element (RARE) of the DR5 class. As expected, this element is able to confer retinoic acid responsiveness to a heterologous promoter. In addition, the HNF-3alpha-specific RARE is able to interact with various retinoic acid receptor heterodimers of the RAR/RXR type. Since HNF-3alpha is induced early during mammalian neurogenesis, our data shed new light on the connection between retinoic-acid-mediated HNF-3alpha activation and establishment of the neuronal phenotype.

Esophageal atresia with blocked distal tracheo-esophageal fistula

A new born male child diagnosed for pure esophageal atresia was subsequently found to have blocked tracheo-esophageal fistula. The case is reported in view of its rarity and difficulty in management.

A report of 27 cases of congenital short colon with an imperforate anus: so-called 'pouch colon syndrome'

This is a retrospective study of 27 cases of congenital short colon with anorectal malformation (pouch colon syndrome) treated during the last 5 years (from January 1991 to December 1995). The radiological feature of enormously dilated colonic pouch occupying more than half the width of abdomen was diagnostic in almost all cases. Excision of pouch and end enterostomy was associated with maximum survival (92.3%) in good risk patients. Proximal diverting enterostomy with decompression and irrigation of pouch is a preferable alternative to pouch colostomy in poor risk patients. Tapering coloplasty and colostomy should be reserved only for types I and II cases of pouch colon.

Abdomino-scrotal lymphangioma

Retroperitoneum, pelvis and scrotum are unusual sites of lymphangiomas. Retroperitoneal lymphangiomas presenting as inguino-scrotal masses are extremely rare. An unusual case of retroperitoneal lymphangioma extending into scrotum, presenting as acute scrotum is reported due to its unusual location. Complete surgical excision with careful attention to avoid damaging contiguous structures is the treatment of choice.

Differential induction of HNF-3 transcription factors during neuronal differentiation

We have investigated the regulation of transcription factors HNF-3alpha and HNF-3beta during the retinoic acid-mediated differentiation of mouse P19 cells. Retinoic acid treatment converts P19 stem cells into neurons and astrocytes and we have clearly shown that gene expression of both HNF-3alpha and HNF-3beta is activated during this process. HNF-3alpha transcription was detected 2 h after addition of retinoic acid and took place in the absence of de novo protein synthesis. This suggests that HNF-3alpha is a primary target for retinoic acid action. HNF-3alpha induction displays a biphasic profile and HNF-3alpha mRNA reaches maximal levels at 2 and 6 days postdifferentiation. Additional experiments strongly suggest that the second peak is due to HNF-3alpha induction in postmitotic neurons. P19 stem cells, on the other hand, do not contain any detectable HNF-3alpha mRNA. According to our studies, the retinoic acid-mediated induction of HNF-3alpha occurs at the level of transcriptional initiation and is conferred by distal promoter sequences. In comparison to HNF-3alpha, HNF-3beta induction is a subsequent event and detectable levels of HNF-3beta mRNA materialize approximately 1 day after addition of retinoic acid to P19 stem cells. Time course studies firmly demonstrate that HNF-3beta mRNA peaks at about 2 days postdifferentiation and then declines to virtually unreadable levels. This temporal pattern is consistent with HNF-3beta being a secondary target for retinoic acid. In analogy to HNF-3alpha, HNF-3beta activation also takes place at the level of transcriptional initiation. Recent studies implicate HNF-3alpha and HNF-3beta in early mammalian neurogenesis. The detection of HNF-3alpha/beta activation during P19 cell differentiation provides us with a convenient cell culture system to elucidate the induction mechanism and the precise role of both transcriptional regulators in the formation of neuronal cells.

Morgagni hernia in a neonate with ventricular septal defect

A neonate with Morgagni hernia and ventricular septal defect is reported. Presentation of Morgagni hernia in neonates is rare, but when it does, it is associated with other congenital anomalies.

Etiology of sporadic acute and fulminant non-A, non-B viral hepatitis in north India

BACKGROUND

Viral hepatitis is a major public health problem in India.

AIM

To investigate the association of various hepatitis viruses in patients with acute liver diseases in north India.

METHODS

One hundred and thirteen patients with acute viral hepatitis (AVH; n = 70) or fulminant hepatic failure (FHF; N = 43) were evaluated for the presence of hepatitis A, B, C and E virus infection. Hepatitis C virus (HCV) testing was done using second-generation anti-HCV ELISA test and reverse transcriptase polymerase chain reaction (PCR) for the detection of HCV RNA in the serum of patients with non-A, non-B (NANB) hepatitis. Detection of IgM anti-HEV antibody was done in patients found negative for the above viruses (n = 53).

RESULTS

Hepatitis A and B viruses accounted for 3.5% and 42.5% of the 113 cases, respectively. HCV infection accounted for 12% of the NANB cases with AVH and 15.5% with FHF. PCR was more useful than serological tests for the detection of HCV infection. HEV infection accounted for 49% of the NANB, non-C cases with AVH and 25% with FHF; pregnant women with HEV infection had a fulminant course. No etiological agent could be established in 28.3% of cases.

CONCLUSION

HEV is the most important cause of NANB hepatitis; hepatitis B virus is still a major concern, while HCV is not an important cause of acute viral liver disease in India.

Regulation of ribosomal RNA gene transcription during retinoic acid-induced differentiation of mouse teratocarcinoma cells

We have examined the mechanism of regulation of rRNA synthesis in mouse F9 teratocarcinoma cells that were induced to differentiate by retinoic acid and dibutyryl cAMP. Ribosomal RNA (rRNA) synthesis was significantly reduced during differentiation of F9 cells into parietal endoderm cells. Nuclear run-on assay revealed that the rRNA gene transcription rates were reduced in differentiated cells, and this phenomenon could be mimicked by in vitro transcription assay using nuclear extracts prepared from F9 stem and F9 parietal endoderm cells. Analysis of the DNA-binding activities of two RNA polymerase I (pol I) transcription factors E1BF/Ku and UBF revealed decreased affinity for their cognate recognition sequences. Immunoblot analysis showed a marked reduction in the amounts of E1BF/Ku and UBF in the differentiated cells. Analysis of the steady-state RNA levels for the smaller subunit of E1BF/Ku and for UBF in differentiating F9 cells revealed decreased mRNA synthesis and increase in message level for the differentiation-specific marker laminin B1 with progression of the differentiated status of the cells. This study has demonstrated that differentiation of mouse F9 teratocarcinoma cells into parietal endoderm cells leads to diminished rRNA synthesis, which may be mediated by reduced DNA-binding activities and amounts of at least two pol I transcription factors.

Accessory scrotum with imperforate anus

Accessory scrotum is the rarest anomaly of the scrotum; less than two dozen cases have been reported. A case of accessory scrotum with imperforate anus is reported.

Huge omental cyst mimicking ascites

An unusual case of omental cyst is described. A 4-year-old child presenting as abdominal distension of short duration, clinically diagnosed as ascites, was subsequently proved to be giant omental cyst. The case is reported because of its unique presentation.

Congenital segmental dilatation of intestine

We are reporting two cases of segmental dilatation of small intestine presenting as neonatal intestinal obstruction. Clinco-pathological features, etiology and management are discussed in brief.

Pyloric membrane and congenital hydronephrosis--a rare association

A rare association of pyloric membrane, Meckel's diverticulum and pelvi-ureteric junction obstruction in a 3-year-old boy is reported.

Duodenal obstruction with isolated levocardia

We report a patient with isolated levocardia without cardiac or splenic defects associated with duodenal membrane.

Endodermal sinus tumour of cervix--case report

Endodermal sinus tumor of Cervix is an extremely rare cause of vaginal bleeding. Because of its rarity and interesting features, it is reported with a brief review of literature.

Delayed activation of HNF-3 beta upon retinoic acid-induced teratocarcinoma cell differentiation

We have investigated the retinoic acid-mediated activation of the transcriptional regulator HNF-3 beta during differentiation of mouse F9 embryonal carcinoma cells. Using gel shifts, HNF-3 beta DNA binding activity was clearly detected in differentiated cells, while F9 stem cells were devoid of this activity. We also demonstrated that HNF-3 beta mRNA is specific for differentiated cells. Addition of retinoic acid to F9 stem cells results in delayed activation of HNF-3 beta mRNA which can be detected 1-2 days after the initiation of differentiation. HNF-3 beta mRNA concentrations are maximal at approximately 4 days postdifferentiation and stay at elevated levels for at least 4 additional days. Nuclear run-on experiments clearly show that HNF-3 beta is activated at the level of transcriptional initiation, suggesting that the increases of beta-specific DNA binding activity and mRNA concentration are merely a reflection of this activation mechanism. F9 cells can give rise to three distinct differentiated cell types, visceral endoderm, parietal endoderm, and primitive endoderm, and we have observed HNF-3 beta stimulation during the formation of all three tissues. HNF-3 beta stimulation upon visceral endoderm differentiation is accompanied by the activation of HNF-3 target genes such as transthyretin, suggesting that HNF-3 beta is involved in the developmental activation of this gene. In contrast, HNF-3 beta target genes in parietal and primitive endoderm have yet to be identified. However, the stimulation of HNF-3 beta during primitive endoderm formation, which is an extremely early event during murine embryogenesis, points toward a role for the factor in crucial determination processes that occur early during development.

Retinoic acid-mediated activation of HNF-3 alpha during EC stem cell differentiation

We present evidence demonstrating that the liver-enriched transcription factor HNF-3 alpha is activated upon retinoic acid-induced differentiation of mouse F9 embryonal carcinoma cells. We have detected increases in the DNA binding activity and mRNA level of HNF-3 alpha. Both are reflections of the actual activation mechanism at the level of transcriptional initiation, which we showed with the help of HNF-3 alpha promoter constructs. Time course studies clearly show that HNF-3 alpha activation is a transient event. Employing Northern blots, HNF-3 alpha mRNA can be detected between 16 and 24 hours post-differentiation, reaches its zenith at approximately 1 day, and then declines to virtually undetectable levels. F9 cells can give rise to three distinct differentiated cell types; visceral endoderm, parietal endoderm, and primitive endoderm. We have clearly shown that HNF-3 alpha stimulation occurs upon primitive endoderm formation. In addition, the transcription factor is also activated during the induction of cell lineages that give rise to parietal and visceral endoderm. HNF-3 alpha stimulation upon visceral endoderm differentiation is accompanied by the activation of HNF-3 target genes such as transthyretin, suggesting that HNF-3 alpha is involved in the developmental activation of this gene. In contrast, HNF-3 alpha target genes in parietal and primitive endoderm have yet to be identified. However, the stimulation of HNF-3 alpha during primitive endoderm formation, which is an extremely early event during murine embryogenesis, points towards a role for the factor in crucial determination processes that occur early during development.