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Dive into the research topics where Ralph C. Cohen is active.

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Featured researches published by Ralph C. Cohen.


Journal of Pediatric Surgery | 1986

Diagnosis and management of massive hepatic hemangiomas in childhood

Ralph C. Cohen; N.A. Myers

Twelve patients diagnosed as having hepatic hemangiomas during 1960 to 1982 at the Royal Childrens Hospital, Melbourne are reviewed. This rare benign vascular tumor can present considerable problems in both diagnosis and management and has a high reported mortality. Our experience over this 23-year period demonstrates some of the difficulties in diagnosis and suggests a plan of management. Eight patients were diagnosed when five weeks of age or less, the youngest was 24 hours old. One was diagnosed at four months of age. In the remaining three patients, the diagnosis was made at postmortem. Ten patients had prominent hepatomegaly, nine had congestive cardiac failure and in one of these the onset was delayed four weeks. Thrombocytopenia was present in five and jaundice in four patients. Four patients had associated cutaneous or visceral hemangiomas. Seven patients underwent selective hepatic arteriography, and two of these had prior ultrasound examinations of the liver. Management of congestive cardiac failure included steroids, radiotherapy, hepatic resection, and in one patient, hepatic artery ligation. One patient with diffuse hepatic hemangiomas did not require any specific therapy and resolved spontaneously over two years. The four patients in whom hepatic resection was performed survived.


Journal of Pediatric Surgery | 1985

The successful reconstruction of thoracic tracheal defects with free periosteal grafts

Ralph C. Cohen; Robert M. Filler; Kunio Konuma; Andre Bahoric; Geraldine Kent; Charles Smith

A defect was created in the thoracic trachea in nine piglets (10 kg) by excising a segment from the entire thoracic trachea proximal to the right upper lobe bronchus (3 to 3.5 cm in length) and 30% of the circumference in width (1 to 1.5 cm). The defect was repaired with a free tibial periosteal graft (FPG) and in four piglets an omental pedicle graft (OPG) was applied to the surface of the FPG. An internal tracheal splint was inserted for 12 to 16 days to support the repair and prevent air leak. The splints were removed bronchoscopically. None of the pigs developed signs of airway obstruction at any stage following the repair. Eight were killed 3 months postoperatively when four to six times their original weight. One pig died on the 18th postoperative day of unknown cause. The tracheas were removed, x-rayed, and examined grossly and histologically. The results demonstrated normal tracheal growth with absence of either stenosis, collapse, or granulation tissue. All grafts were viable, bone formation was present, and the lumenal surfaces were lined with columnar and respiratory epithelium. The OPG did not improve vascularization of the FPG. This model suggests that tracheal stenosis in children may be surgically corrected by simply incising the stenotic segment longitudinally and enlarging the tracheal diameter by inserting a FPG into the defect.


Journal of Pediatric Surgery | 2013

Hepaticoduodenostomy versus hepaticojejunostomy after resection of choledochal cyst: A systematic review and meta-analysis

Sarath Kumar Narayanan; Yong Chen; Kannan Laksmi Narasimhan; Ralph C. Cohen

BACKGROUND Excision has been established as a standard management practice for choledochal cysts in the last few decades. The two most commonly performed methods of reconstruction after excision are hepaticoduodenostomy (HD) and Roux-en-Y hepaticojejunostomy (HJ), of which the HJ is favored by most surgeons. Evidence concerning the optimal method of reconstruction is, however, sparse. MATERIALS AND METHODS Studies comparing outcomes from HD and HJ after choledochal cyst excision were identified by searching Medline, Ovid, Search Medica, Elsevier Clinicalkey, Google Scholar and Cochrane library. Suitable studies were chosen and data extracted for meta-analysis. Outcomes evaluated included operative time, hospital stay and incidence of postoperative bile leak, cholangitis, reflux/gastritis, anastomotic stricture, bleeding, intestinal obstruction and re-operative rate. Pooled odds ratios (OR) were calculated for dichotomous variables; pooled mean differences (MD) were measured for continuous variables. RESULTS Six retrospective studies were included in this meta-analysis, comprising a total of 679 patients, 412 of whom (60.7%) underwent HD, and the remainder, 267 (39.3%) underwent HJ. Although, HD group had slightly shorter hospital stay (MD: 0.30; 95% CI: -0.22-0.39; P < 0.00001) it showed a higher incidence of postoperative reflux/gastritis (OR: 0.08; 95% CI: -0.02-0.39; P = 0.002). However, the other outcomes such as bile leak, cholangitis, anastomotic stricture, bleeding, operative time, reoperation rate and adhesive intestinal obstruction did not differ between HD and HJ groups. CONCLUSIONS HD shows higher postoperative reflux/gastritis than HJ but a shorter hospital stay. There are few good-quality studies that compare the outcomes from HD and HJ, meaning that caution should be exercised in the generalization of the results of this meta-analysis, which suggests HD to be comparable with HJ in terms of other complications, operative benefits and outcomes.


Journal of Pediatric Surgery | 1999

Successful endoscopic drainage of a posttraumatic pancreatic pseudocyst in a child.

Roy M. Kimble; Ralph C. Cohen; Stephen Williams

The successful endoscopic drainage of a posttraumatic pancreatic pseudocyst in a 9-year-old boy is described. This case study suggests that there is a role for endoscopic placement of stents in the treatment of pancreatic pseudocysts in children.


Pediatric Surgery International | 2001

Urethral trauma in children

Andrew J. A. Holland; Ralph C. Cohen; K. M. F. McKertich; D. T. Cass

Abstract We report our 12-year experience in the management of urethral injuries in nine children, six boys and three girls. The most common mechanisms of injury were motor vehicle accidents, followed by straddle injuries. All the injuries in boys involved the anterior urethra, and in girls the proximal or mid-urethra. There were associated injuries in five, including three pelvic fractures. All children were investigated with a retrograde urethrogram. Four were treated non-operatively with insertion of a urethral catheter. Of the remaining five, one had drainage of a penile haematoma, one cystourethroscopy, two insertion of urinary and suprapubic catheters, and one open cystotomy and passage of a guide wire with antegrade passage of a urethral catheter. Complications included one urinary tract infection, one urethral fistula, one urethrovaginal fistula, and two urethral strictures. Final outcome was satisfactory in all nine children.


PLOS Pathogens | 2015

Relay of herpes simplex virus between Langerhans cells and dermal dendritic cells in human skin.

Min Kim; Naomi R. Truong; Virginia James; Lidija Bosnjak; Kerrie J. Sandgren; Andrew N. Harman; Najla Nasr; Kirstie M. Bertram; Norman Olbourne; Shailandra Sawleshwarkar; Kaylene McKinnon; Ralph C. Cohen; Anthony L. Cunningham

The mechanism by which immunity to Herpes Simplex Virus (HSV) is initiated is not completely defined. HSV initially infects mucosal epidermis prior to entering nerve endings. In mice, epidermal Langerhans cells (LCs) are the first dendritic cells (DCs) to encounter HSV, but it is CD103+ dermal DCs that carry viral antigen to lymph nodes for antigen presentation, suggesting DC cross-talk in skin. In this study, we compared topically HSV-1 infected human foreskin explants with biopsies of initial human genital herpes lesions to show LCs are initially infected then emigrate into the dermis. Here, LCs bearing markers of maturation and apoptosis formed large cell clusters with BDCA3+ dermal DCs (thought to be equivalent to murine CD103+ dermal DCs) and DC-SIGN+ DCs/macrophages. HSV-expressing LC fragments were observed inside the dermal DCs/macrophages and the BDCA3+ dermal DCs had up-regulated a damaged cell uptake receptor CLEC9A. No other infected epidermal cells interacted with dermal DCs. Correspondingly, LCs isolated from human skin and infected with HSV-1 in vitro also underwent apoptosis and were taken up by similarly isolated BDCA3+ dermal DCs and DC-SIGN+ cells. Thus, we conclude a viral antigen relay takes place where HSV infected LCs undergo apoptosis and are taken up by dermal DCs for subsequent antigen presentation. This provides a rationale for targeting these cells with mucosal or perhaps intradermal HSV immunization.


Pediatric Surgery International | 2006

Combined ileal heterotopic pancreatic and gastric tissues causing ileocolic intussusception in an infant

A. Al-Zahem; Susan Arbuckle; Ralph C. Cohen

Pathological intussusception is rare in infancy with Meckel’s diverticulum being the most common lesion. Isolated heterotopic pancreatic tissue in the serosa of the ileum causing intussusception is extremely rare. We report a case of ileal heterotopic pancreatic tissue associated with ectopic gastric mucosa causing ileocolic intussusception in an infant, with review of the literature.


Journal of Paediatrics and Child Health | 1982

Blunt splenic trauma in children: a retrospective study of non-operative management

Ralph C. Cohen

ABSTRACT. This paper is a retrospective study of the management of 58 cases of blunt splenic injury in the paediatric age group. Fifty of these cases were managed at the Adelaide Childrens Hospital during the period 1964–1980 and eight cases at the Flinders Medical Centre during the period 1976–1980.


Pediatric Surgery International | 2007

Atypical congenital mesoblastic nephroma presenting in the perinatal period

Vinci S. Jones; Ralph C. Cohen

Congenital mesoblastic nephroma (CMN) is a rare tumour of infancy having an overall good prognosis. The less common, atypical CMNs have cellular elements in them and tend to have an unpredictable course. Occurrence in the perinatal period may further change the outcome. By reporting three patients presenting in the perinatal period with atypical CMN, an attempt is made in this paper to characterize the clinical behaviour of these variant tumours. Though one of our patients had an uneventful course, the other two had several complications including polyhydramnios, prematurity, hypertension, haemodynamic instability and tumour spillage. The course was complicated by recurrence in the latter two and refractoriness to chemotherapy and death in one. That the atypical subset of CMNs occurring in the perinatal period can have a stormy course is well illustrated by this report. Possible prognostic factors are evaluated and the sparse reports of similar cases in the literature are reviewed and compared.


Journal of Laparoendoscopic & Advanced Surgical Techniques | 2012

Porcine Models for Pediatric Minimally Invasive Surgical Training—A Template for the Future

Sandeep S. Bidarkar; Aniruddh V. Deshpande; Mandeep Kaur; Ralph C. Cohen

Pediatric minimally invasive surgery is a rapidly developing field with a steep learning curve for each new procedure that is developed and integrated into practice. The European consensus is that the training across the learning curve should not be on the patients. Simulation is a widely accepted methodology to shorten the learning curve. Training on animal models is an advanced form of simulation. This helps to reduce morbidity and the costs of patient care. This article describes our 3 years of experience in the development of animal models for training in pediatric minimally invasive surgery.

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Vinci S. Jones

Children's Hospital at Westmead

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D. T. Cass

Children's Hospital at Westmead

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Sarath Kumar Narayanan

Children's Hospital at Westmead

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James Wood

University of New South Wales

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Albert Shun

Children's Hospital at Westmead

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Andrew J. A. Holland

Children's Hospital at Westmead

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Sandeep S. Bidarkar

Children's Hospital at Westmead

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Susan Arbuckle

Children's Hospital at Westmead

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Gordon Thomas

Children's Hospital at Westmead

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