Current status in the surgical management of adult polycystic liver disease.

INTRODUCTION: In patients with adult polycystic liver disease (APLD), there is considerable debate surrounding the most effective way of managing symptomatic cysts. Conservative approaches like percutaneous aspiration or cyst fenestration are associated with low morbidity but high recurrence rates. Conversely, liver resection and hepatectomy with orthotopic liver transplantation is drastic and associated with high morbidity and mortality rates. Our aim is to review the current understanding of liver cystogenesis in these patients and the therapeutic options available in order to provide a rationale guide to management of this intriguing condition. METHODS: This article summarises the findings of published papers in major international journals indexed on MEDLINE on APLD using the key words--adult polycystic liver disease, liver cysts, fenestration, liver resection, liver transplantation and polycystic kidney disease. The period of search includes papers between 1965 and 2000. RESULTS: Published studies have suggested a 'two-hit' hypothesis to explain the development of liver cysts in patients with APLD. This will provide the rationale for future management. Meanwhile, the indications, pitfalls and results of the various therapeutic options are reviewed. Management of symptoms has to be tailored to the underlying severity of the liver cystic disease, co-morbidity and procedural risks and recurrence rates. CONCLUSION: Good long-term relief of symptoms can be achieved with the correct procedure at acceptable morbidity and mortality rates. We have provided guidelines on the various options available to enable a structured approach to the management of APLD.

Does laparoscopic fenestration provide long-term alleviation for symptomatic cystic disease of the liver?

BACKGROUND: The use of laparoscopic technique for management of symptomatic liver cysts is documented to be a feasible and safe procedure with good short-term symptomatic relief. However, it cannot be recommended as the standard of care as long-term results are scarce. The present study was initiated to review the long-term results of this approach in the management of symptomatic liver cysts. METHODS: A retrospective review of all patients with symptomatic liver cysts that were treated by laparoscopic fenestration in our department over an 8-year period from 1993 to 2001. The clinical and radiographical data were analysed at follow-up to assess the -outcome. RESULTS: Eleven patients were treated using a laparoscopic approach; 10 patients with solitary cysts and one with adult polycystic liver disease. All patients achieved short-term alleviation of symptoms and an uneventful postoperative course. The mean hospital stay was 3 days. Long-term follow up was available for 9 patients with a mean of 44 months. Histologically, one of the patients was diagnosed with a biliary cystadenoma and she had a symptomatic recurrence and a liver resection at 20 months. In the other seven patients, there was no clinical recurrence but a radiographical recurrence of 28.5%. The patient with adult polycystic liver disease had two symptomatic recurrences: at 26 months where he underwent a repeat laparoscopic fenestration and at 43 months where he underwent an open fenestration. CONCLUSION: The present study confirms that with adequate patients election, long-term alleviation of symptoms can be achieved with the laparoscopic approach for solitary simple liver cysts but not for polycystic liver disease or cystic tumours of the liver.

Inhibition of angiopoietin-1 expression in tumor cells by an antisense RNA approach inhibited xenograft tumor growth in immunodeficient mice.

Angiopoietin-1 (Ang1) is an angiogenic growth factor that functions through activation of its endothelium-specific tyrosine kinase receptor Tie2; it mediates the interaction between endothelial and surrounding cells to promote the remodeling, maturation and stabilization of blood vessels. Although Ang1 is expressed constitutively in many adult tissues, its role in tumor growth and metastasis is not clear. Here we describe experiments in which Ang1 expression was inhibited in HeLa cells by an antisense RNA approach. The modified HeLa cells produced significantly less Ang1 protein both in cultured cells and in tumors formed when these cells were injected into immunodeficient mice. The Ang1 antisense tumors grew much more slowly, with significantly reduced tumor angiogenesis compared with control tumors. Furthermore, they also had substantially increased tumor cell apoptosis and decreased tumor necrosis. Our results indicate that the perturbation of Ang1 expression in tumors could be an effective method to control tumor growth by inhibiting tumor angiogenesis and that antisense RNA is an efficient way to inhibit Ang1 protein production in tumor cells.

A simple method of blood pressure measurement in the pig using a neonatal cuff.

The pig is a commonly used large animal model in experimental studies. Few non-invasive techniques exist however for the measurement of blood pressure in the porcine model. This study evaluates the novel use of the easily available neonatal blood pressure cuff for measuring blood pressure in the pig. Six Yorkshire pigs were used for the study. Blood pressure measurements obtained by the application of neonatal blood pressure cuff (Hewlett Packard) around the base of the tail were compared with results obtained from intra-arterial measurements in the normotensive range as well as in experimentally created hypertensive (intravenous dopamine) and hypotensive (hypovolaemic shock) ranges. Results of the two techniques are closely correlated (Pearson's coefficient = 0.95, 0.97, 0.90). Systematic bias was however detected at the extremes of hypertensive and hypotensive blood pressure. Analysis of the limits of agreement (method of Bland and Altman) showed that neonatal blood pressure cuff measurements fall within--2 to 2.5 mmHg of the readings obtained from the invasive technique (95% confidence interval). The neonatal blood pressure cuff technique is a good substitute for the standard invasive intra-arterial measurement of blood pressure in the pig model.

An animal model for the study of hepatic stellate cell and hepatocellular carcinoma interaction.

The recognition of hepatic stellate cells (HSC) around and within hepatocellular carcinoma (HCC) in human livers has generated interest in the interactions between HSC and HCC. We explored the possibility of creating an animal model to allow in vivo investigations of this interaction. Eighteen adult Buffalo rats were inoculated with 1 x 10(6) cells obtained from cultures of Morris 7777 hepatoma cell line (ATCC). The rats were sacrificed at 2-, 3-, and 4-week intervals. Identification of activated HSC was with immunohistochemistry for alpha-smooth muscle actin (alpha-SMA). There was 100% survival of all animals until sacrifice. Tumour formation occurred in 94.4% of rats, and was of a good size by two weeks. Expression of alpha-SMA was observed around and within all HCC, but absent from normal tissue, and this showed colocalisation with collagen deposition. These findings are consistent with those previously reported in resected HCC in humans. The high survival, good tumour yield, consistent generation of activated HSC around the tumours, and similarities in histological appearance to the human HSC-HCC distribution pattern, make this a reliable animal model for in vivo studies on HSC-HCC interaction.

A practical technique of colour image analysis: applications in experimental research.

Commercially available colour image analysers are relatively expensive. We describe a cheaper alternative developed by the Department of Experimental Surgery, Singapore General Hospital using an assembly of optical and computer equipment commonly available in the research laboratory. This manual colour imaging system is comparable to the commercial model in terms of functional capabilities and accuracy, except that it takes a longer time to process and analyse images and is unable to measure colour density. However, it is capable of not only analysing microscopic images of stained histological tissue sections but also X-ray images and images of large pathological specimens. In the case of commercial models, different systems have to be used to analyse images from different types of specimens. This system was developed in 1987 and has since been used successfully in a number of experimental studies. It has been applied to the measurement of parameters defining eye anatomical configuration, delineating the extent of tissue necrosis and fibrosis after therapeutic treatment and surgery, the development of new bone formation in fracture healing and to quantitative studies in liver regeneration. Due to its accuracy, low cost and versatility, this system should be within the means of even the most modest research laboratory.

Degenerative changes of afferent neurons in the lumbosacral dorsal root ganglia following complete urethral obstruction in guinea pigs.

OBJECTIVE: The ultrastructural changes in the bladder afferent neurons were examined in the guinea pig following acute complete urethral obstruction. MATERIAL AND METHODS: Complete urethral ligation was carried out in nine guinea pigs under anaesthesia and the animals were sacrificed at 12, 24 and 48 h postoperatively. Three sham-operated animals were sacrificed at 48 h postoperatively as controls. The dorsal root ganglia (DRG) at L6, S1 and S2 spinal segments of the animals in each group were removed and processed for electron microscopic study. RESULTS: In the control groups, all the DRG neurons at L6-S2 segments appeared normal. At 12 h after urethral ligation, a few neurons in the DRG at various segments showed signs of structural changes, notably the mitochondria. Mitochondrial swelling was more pronounced at 24 h, and by 48 h most of them became vacuolated and lysed. It was estimated by semiquantitative study that 18.6% and 22% of DRG neuronal profiles at 24 and 48 h, respectively, displayed severe mitochondrial swelling and vacuolation. CONCLUSIONS: The observed degenerative changes in DRG neurons following complete urethral obstruction may be a cellular reaction in response to the axonal injury elicited by bladder overdistension. This may account for alterations in visceral sensation in patients with acute urinary retention.

Localization of nicotinamide adenine dinucleotide phosphate-diaphorase reactivity and nitric oxide synthase immunoreactivity in the lumbosacral dorsal root ganglia in guinea pigs.

This study examined the distribution of reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) reactivity and nitric oxide synthase (NOS) immunoreactivity in the lumbosacral dorsal root ganglia (DRG) in male guinea pigs. A differential distribution of NADPH-d reactivity and NOS immunoreactivity was detected in neurons of DRG at different segmental levels. There were numerically more intensely stained NADPH-d and NOS reactive cells in the rostral (L1-L3) DRG compared with those at the caudal (L6-S4) levels. In the corresponding DRG, NADPH-d reactivity was not paralleled by NOS immunoreactivity. This was evidenced by the wide distribution of afferent neurons in the lumbosacral DRG stained for NADPH-d, yet only a small number of them exhibited NOS immunoreactivity. Double labelling study has shown that some of the NADPH-d positive neurons were NOS negative. Ultrastructurally, NADPH-d reaction product was associated with the membranes of various subcellular organelles, including the rough endoplasmic reticulum (rER), Golgi saccules, mitochondria and some segments of the nuclear envelop, whereas NOS immune-precipitate was patchily distributed throughout the cytoplasm. Present results suggest that nitric oxide (NO) may function as a neurotransmitter in the afferent pathways at lumbosacral segments. On the other hand, in view of their marked disparity in numbers and the lack of total one-to-one correspondence, it seems likely that the NOS positive neurons represent only a subpopulation of the NADPH-d positive cells in the lumbosacral DRG.

Norcantharidin inhibits growth of human HepG2 cell-transplanted tumor in nude mice and prolongs host survival.

In this study, norcantharidin was compared with adriamycin and mitomycin C for its inhibitory action in the growth of cultured human hepatocellular carcinoma HepG2 cells. The IC50 of adriamycin and mitomycin C on HepG2 cells was 7.3 microM and 27 microM, respectively, whereas the IC50 of norcantharidin for inhibiting the growth of HepG2 cells was as high as 1900 microM. After HepG2 tumor-bearing nude mice were treated with 12 daily intraperitoneal injections of norcantharidin (2 mg/kg), the increase in tumor size was significantly slower than that of untreated controls. The mean survival time of untreated tumor-bearing nude mice was 129 days, whereas in the tumor-bearing nude mice treated with norcantharidin, the mean survival time was significantly prolonged to 194 days (P < 0.0001). It is concluded that norcantharidin may have a potential role in the treatment of human hepatocellular carcinoma.

Laparoscopic hernia repair in Singapore--views from a cross-section of surgeons.

Laparoscopic cholecystectomy was introduced into Singapore in 1990, and has since replaced conventional cholecystectomy as the treatment of choice for gallstone disease in most situations. In contrast, laparoscopic hernia repair introduced two years later in the same wave of enthusiasm, was received with scepticism and much less acceptance. A survey of 27 general surgeons in three large institutions in Singapore was performed to analyse this observation. The majority of surgeons felt that laparoscopic hernia repair (i) had limited applications, mainly for bilateral and recurrent hernias, (ii) was not completely established as a technique, requiring refinement in the procedure, (iii) was costly, and (iv) did not have objective evidence of long-term benefits over conventional hernia repair.

Tumour suppressor p53 and Rb genes in human hepatocellular carcinoma.

Aberrations of the p53 and Rb tumour suppressor genes were examined in 12 human hepatocellular carcinoma (HCC)-derived cell lines from different geographic areas and 9 local HCCs by restriction fragment length polymorphisms (RFLP), polymerase chain reaction-single-strand conformation polymorphisms (PCR-SSCP) and DNA sequencing. The relationships between genetic changes and hepatitis B virus (HBV) DNA integration in samples were compared. None of the cell lines and tumours showed structural changes in the Rb gene, while 6 cell lines and 2 tumours had mutation or deletion in exons 5 to 8 of p53. Mutations include an AGG --> AGT (Arg --> Ser) transversion at codon 249 in PLC/PRF/5 and Mahlavu, an AAT --> AAA (Asn --> Cys) transversion at codon 200 in TONG/HCC, an AAG --> GAG (Lys --> Glu) transition at codon 139 in HCC-T, a CAT --> CGT (His --> Arg) transition at codon 214 in SC4, and a CCC --> CTC (Pro --> Leu) transition at codon 250 in SC8. In Huh4, an 18-bp deletion from codon 264 to 270 resulted in loss of Leu-Gly-Arg-Asn-Ser-Phe from the amino acid sequences 265 to 270, whereas Hep3B had a 7-kb deletion after exon 7 of p53. Our data indicate that whereas Rb may not have pleiotropic effects on HCC, p53 aberrations are frequently involved in hepatocarcinogenesis. Further, HBV infection appears to be unrelated to the micro-genetic changes of p53. The G to T codon-249-mutation is consistent with HCCs arising from areas at high risk for both aflatoxin B1 (AFB1) exposure and HBV infection.

Thoracoscopic vagotomy for peptic ulcer disease--report of two cases.

Thoracoscopic vagotomy is a well-established technique in the management of recurrent peptic ulceration after previous abdominal vagotomy. The procedure allows an easy approach to the vagus nerves without having to dissect through dense adhesions from previous surgery. With thoracic vagotomy, the main morbidity is postoperative pain from the thoracotomy incision and rib spreading. Advances in endoscopic camera systems and instrumentation allow thoracic vagotomy to be safely and effectively accomplished by thoracoscopic surgery techniques, with reduced postoperative pain. We describe our experiences with thoracoscopic vagotomy in two cases of recurrent peptic ulceration.

Anaesthesia for animals in experimental research.

Animal anaesthesia is a wide and varied subject considering the great number of available animal models, each having its characteristic tolerance and reaction to anaesthesia and its behavioural peculiarity. It is more often than not that experimental researchers tend to give scant attention to animal anaesthesia in the preparation of a research protocol as a result of which their research findings can become difficult or impossible to interpret. This article outlines the fundamental anaesthetic requirements and techniques in various animals and the practices adopted by the Department of Experimental Surgery, Singapore General Hospital. Consideration in the choice of anaesthetic drugs in various animal models and experimental situations, and problems of animal handling before and after anaesthesia are highlighted.

Laparoscopic marsupialization of liver cysts.

The majority of benign, non-parasitic liver cysts are asymptomatic. Surgical treatment is reserved for symptomatic patients and frequently involves partial excision or marsupialization via a laparotomy. Surgery is occasionally offered for asymptomatic large cysts, where complications of cyst rupture, intra-cystic bleeding and infection are more common. The authors describe three cases of symptomatic liver cysts that were effectively marsupialized laparoscopically with good results.

Laparoscopic assessment and orchidectomy for the undescended testis.

Cryptorchidism is the most common disorder of male sexual differentiation. Pre-operative assessment and localization of undescended testes by various investigatory modalities have been of limited clinical value. The recent use of diagnostic and therapeutic laparoscopy for undescended testis peri-operatively has been shown to be safe and informative in the planning of appropriate surgical management. The authors' initial experience with this procedure, for five patients with unilateral undescended testis, is presented.

Laparoscopy-guided percutaneous cholecystolithotomy: an evolving technique.

Gall-bladder conservation therapy has been evolving during the past decade. Popular techniques of conservative therapy are extracorporeal shock wave lithotripsy (ESWL) and medical dissolution therapy. The limitations of these procedures have prompted a search for alternative techniques, particularly in relation to percutaneous stone extraction. The cases of four patients with symptomatic gallstones who underwent percutaneous cholecystolithotomy under laparoscopic guidance are reported. The gall-bladder was punctured with a long needle and the tract dilated so that a nephroscope could be introduced. Three cases required stone fragmentation by an ultrasonic lithotripter before removal. Postoperative recovery was uneventful in all cases.

Splenic abscess.

Isolated splenic abscess is an uncommon condition. Seven cases seen between 1980 and 1990 are reviewed. The clinical presentation is non-specific and diagnosis is usually delayed. Computerized tomography allowed for accurate diagnosis in all cases. Pseudomonas species as a causative organism is reported to be rare, but were present in three of the present cases. Antibiotic therapy alone is insufficient and splenectomy remains the treatment of choice.