[Revision of failed dacryocystorhinostomies using the transcanalicular approach. Results of 118 procedures]

PURPOSE

To assess the efficacy of transcanalicular dacryocystorhinostomy for the revision of other procedures. The results are analyzed following the use of two different types of laser: the Neodymium: YAG (Nd: YAG) laser and the Holmium: YAG (Ho: YAG) laser. To study the efficacy of using two antimetabolite drugs in this context: mytomycin-C (MMC) and 5-fluoro-uracile (5-FU).

METHODS

One hundred and fourteen patients were operated on. Of these, 88 had already undergone one procedure, 25 two procedures, and 5 three procedures. The Nd: YAG laser was used in 78 procedures, the Ho: YAG in 30 procedures, and both lasers in 10 procedures. Twenty patients were treated with an application of MMC and 25 patients with an application of 5-FU.

RESULTS

The results are based on 106 procedures. The total success rate was 49.06% after one revision and 58.49% after two or three revisions. There is no statistically significant difference between the Nd: YAG and Ho: YAG lasers. The use of antimetabolites did not improve the success rate.

CONCLUSION

Transcanalicular dacryocystorhinostomy is a very useful method because it does not cause cutaneous scarring and it has a low rate of morbidity given that it causes very little surgical traumatism. The revision of other dacryocystorhinostomy methods using the transcanalicular approach is theoretically a positive indication because it does not dissect scarring tissues and because the osteotomy has already been performed. However, the success rate is lower than for the external and endonasal approaches. The success rate is not modified by the use of antimetabolites or by the type of laser.

Combined cataract and glaucoma surgery

The management of cataract in glaucoma patients has been continuously changing over the past decade. Extracapsular cataract extraction has been replaced by small-incision phacoemulsification with foldable lenses, and in glaucoma surgery, adjunctive antifibrotic therapy based on risk factors for failure has become standard. Furthermore, new techniques in filtering and nonfiltering surgery have been suggested. The techniques, however, change so fast that well-controlled studies with a follow-up of more than 12 months are increasingly seldom. The purpose of this paper is to review the current literature and to point out some new ideas for the future investigation.

Antimetabolites and cytotoxic drugs

Mycophenolic mofetil, azathioprine, thioguanine, methotrexate, and cyclophosphamide were initially used for the treatment of malignancies. Because of their immunosuppressive activity, the range of diseases responsive to these medications has expanded to include various autoimmune-related diseases. Discussion includes a historical perspective of each medication, recent updates on responsive dermatologic conditions, dosages, monitoring guidelines, and medication expense.

Adjuvant clodronate treatment does not reduce the frequency of skeletal metastases in node-positive breast cancer patients: 5-year results of a randomized controlled trial

PURPOSE

Bisphosphonates have effectively reduced the development and progression of bone metastases in advanced breast cancer. The aim of this study was to determine whether bone metastases could be prevented by adjuvant clodronate treatment in patients with primary breast cancer.

PATIENTS AND METHODS

Between 1990 and 1993, 299 women with primary node-positive breast cancer were randomized to clodronate (n = 149) or control groups (n = 150). Clodronate 1,600 mg daily was given orally for 3 years. All patients received adjuvant therapy: premenopausal six cycles of CMF chemotherapy and postmenopausal antiestrogens (randomized to tamoxifen 20 mg or toremifene 60 mg/d for 3 years). Seventeen patients were excluded from the analyses because of major protocol violations. The final population was 282 patients. Intent-to-treat analyses were also performed for all major end points. The follow-up time was 5 years for all patients.

RESULTS

Bone metastases were detected equally often in the clodronate and control groups: 29 patients (21%) versus 24 patients (17%) (P: = .27). The development of nonskeletal recurrence was significantly higher in the clodronate group compared with controls: 60 patients (43%) versus 36 patients (25%) (P: = .0007). The overall survival (OS) and disease-free survival (DFS) rates were also significantly lower in the clodronate group than in the controls (OS, 70% v 83%, P: = .009; DFS, 56% v 71%, P: = .007, respectively). In multivariate analyses, clodronate remained significantly associated with DFS (P: = .009).

CONCLUSION

Adjuvant clodronate treatment does not prevent the development of bone metastases in node-positive breast cancer patients. However, clodronate seems to have a negative effect on DFS by increasing the development of nonskeletal metastases.

Intra-operative mitomycin C for glaucoma surgery

BACKGROUND

Trabeculectomy is performed as a treatment for many types of glaucoma in an attempt to lower the intra-ocular pressure. Mitomycin C is an antimetabolite applied between the sclera and conjunctiva during the initial stages of a trabeculectomy to prevent excessive post-operative scarring and thus reduce the risk of failure.

OBJECTIVES

The objective of this review is to assess the effects of intra-operative application of mitomycin C in eyes of people undergoing trabeculectomy.

SEARCH STRATEGY

We searched the Cochrane Eyes and Vision Group specialised register, The Cochrane Controlled Trials Register - CENTRAL, MEDLINE, EMBASE and the reference lists of relevant articles. We used the Science Citation Index to search for articles that cited the included studies. We contacted investigators and experts for details of additional relevant trials.

SELECTION CRITERIA

We included randomised trials of intra-operative mitomycin C compared to placebo in trabeculectomy.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. We contacted trial investigators for missing information. Data were summarised using relative risk, odds ratio and weighted mean difference.

MAIN RESULTS

This review includes 11 trials involving a total of 698 participants. The trials included three types of participants (those at high risk of failure, those undergoing trabeculectomy combined with cataract surgery, and those with no previous surgical intervention). Mitomycin C appears to be effective in reducing the relative risk of failure of trabeculectomy both in eyes at high risk of failure (relative risk 0.32, 95% confidence interval 0.20 to 0.53) and those undergoing surgery for the first time (relative risk 0.29, 95% confidence interval 0.16 to 0.53). No significant effect on failure was noted in the group undergoing trabeculectomy combined with cataract extraction. Mean intra-ocular pressure was significantly reduced at 12 months in all three participant groups receiving mitomycin C compared to placebo. No significant increase in permanent sight threatening complications was detected. Some evidence exists that mitomycin C increases the risk of cataract. The quality of trial reporting is poor in eight trials. Repeat analysis with three trials rated as low risk of bias did not yield different results.

REVIEWER'S CONCLUSIONS

Intra-operative mitomycin C reduces the risk of surgical failure in eyes that have undergone no previous surgery and in eyes at high risk of failure. Compared to placebo it reduces mean intra-ocular pressure at 12 months in all groups of participants in this review. Apart from an increase in cataract formation following mitomycin C, no demonstrable significant increase in other side effects was detected.

Resistance of hepatitis B virus to antiviral drugs: current aspects and directions for future investigation

Despite the existence of vaccines, chronic hepatitis B virus (HBV) infection remains a major health problem worldwide. Interferon therapy successfully controls infection in only a small percentage of chronically infected individuals. The recent approval of the nucleoside analogue lamivudine for the treatment of chronic HBV infection has ushered in a new era of antiviral therapy. While lamivudine is highly effective at controlling viral infection short-term, prolonged therapy has been associated with an increasing incidence of viral resistance. Thus, it appears that lamivudine alone will not be sufficient to control chronic viral infection in the majority of individuals. In addition to lamivudine, several new nucleoside and nucleotide analogues that show promising antihepadnaviral activity are in various stages of development. Lamivudine resistance has been found to confer cross-resistance to some of these compounds and it is likely that resistance to newer antivirals may also develop during prolonged use. Drug resistance therefore poses a major threat to nucleoside analogue-based therapies for chronic HBV infection. Fortunately, combination chemotherapy (antiviral therapy with two or more agents) can minimize the chance that resistance will develop and can be expected to achieve sustained reductions in viral load, provided that suitable combinations of agents are chosen. Here we review the basis of drug resistance in HBV, with emphasis on aspects that are likely to affect drug choice in future.

Medical therapies for ulcerative colitis and Crohn's disease

This review focuses on data reported in the last year on medical treatment of Crohn's disease and ulcerative colitis. In Crohn's disease, a broad range of cytokine-based therapies are currently being tested. Although all are very exciting, the anti-tumor-necrosis-factor (TNF) approach remains the most effective, with infliximab (a chimeric monoclonal antibody directed against TNF) being the most active agent. With repeated infusions every 8 weeks, remission is induced and can be maintained even in refractory patients with no major apparent side effects. Thalidomide, an oral agent with anti-TNF effects, shows promise in non-controlled experience. Important new data on azathioprine/6-mercaptopurine (6-MP) and its metabolites are also helpful. Methotrexate can induce remissions in 6-MP-allergic or refractory Crohn's patients and has now shown efficacy as a maintenance agent. Beneficial effects are also reported for a variety of new agents: mycophenolate mofetil, tacrolimus (FK506), growth hormone, and granulocyte colony-stimulating factor (G-CSF). Important observations in ulcerative colitis (UC) over the past year include evidence of a protective effect of 5-aminosalicylic acid (5-ASA) with respect to colorectal cancer, negative results from a study for heparin monotherapy, and results from a comparison of mycophenolate mofetil versus azathioprine as maintenance therapy. Epidemiologically, the negative association between appendectomy and UC was corroborated in a meta-analysis, suggesting an immunologic role for this organ. Finally, in chronic pouchitis, probiotic therapy was found to maintain remissions very significantly.

6-mercaptopurine or methotrexate added to prednisone induces and maintains remission in steroid-dependent inflammatory bowel disease

BACKGROUND

As treatment of steroid-dependent patients with inflammatory bowel disease (IBD) is controversial, we analysed the efficacy and tolerance of 6-mercaptopurine (6-MP) and methotrexate (MTX) added to prednisone in increasing and maintaining the disease remission rate.

METHODS

Seventy-two steroid-dependent IBD patients, 34 with ulcerative colitis (UC) and 38 with Crohn's disease (CD), receiving treatment with prednisone were randomly assigned in a 2:2:1 ratio to additionally receive, orally, over a period of 30 weeks 1.5 mg/kg/day of 6-MP (group A) or 15 mg/week of MTX (group B), or 3 g/day of 5-aminosalicylic acid (5-ASA) (group C). All patients who achieved remission were included in a maintaining remission study for 76 weeks. Remission was defined after stopping prednisone as a CD activity index of <150 and normal serum orosomucoid concentration for CD patients and a Mayo Clinic score <7 for UC patients.

RESULTS

With regard to achieved remission, a significantly higher (P< 0.05) rate existed for UC patients in group A (78.6%) than in group C (25%), with no statistical differences in group B (58.3%) versus C. For CD patients, the rates were significantly higher (P< 0.001 and 0.01, respectively) in groups A (93.7%) and B (80%) versus C (14%). With regard to maintaining remission, UC patients in group A (63.6%) presented significantly higher rates (P < 0.0015 and P < 0.001, respectively) versus 14.3% in group B and none in group C. For CD patients, statistical differences (P < 0.001) existed when comparing rates in groups A (53.3%) and B (66.6%) versus none in group C. Noticeable side effects appeared in 13.3% of patients from group A and 11.5% from group B.

CONCLUSIONS

These results suggest that 6-MP or MTX added to prednisone could be effective in steroid sparing, as well as in achieving and maintaining remission in steroid-dependent IBD patients. MTX was less effective in maintaining remission in UC patients.

Success criteria and success rates in trabeculectomy with and without intraoperative antimetabolites using intensified postoperative care (IPC)

PURPOSE

To define the success rate of trabeculectomy for surgical treatment of glaucoma under intensified postoperative care (IPC) conditions in cases of severe visual field damage or progression of visual field loss.

METHODS

In a retrospective study, we evaluated the outcome of trabeculectomy in 99 eyes of 99 patients from October 1995 to June 1997. In 23 eyes, antimetabolites were used intraoperatively. Regarding intraocular pressure (IOP), success was defined as lowering the preoperative, maximally treated IOP by more than 20% in addition to a postoperative IOP level lower than 21 mmHg without using further glaucoma medication. Success rate was defined by stabilisation of visual acuity and visual field in addition to IOP reduction.

RESULTS

The postoperative IOP was 14.7 mmHg (+/- 3.4 mmHg) following standard trabeculectomy (preoperative IOP 24.3 +/- 6.7 mmHg) and 15.8 mmHg (+/- 4.9 mmHg) following trabeculectomy with intraoperative antimetabolites (preoperative IOP 27.0 +/- 9.5 mmHg). The success rate concerning the IOP was 83% in standard trabeculectomy and 74% following trabeculectomy with intraoperative antimetabolites. The visual acuity showed stabilisation in 93% of cases following standard trabeculectomy and in 100% following trabeculectomy with intraoperative antimetabolites. The visual field showed stabilisation according to the Aulhorn criteria in 95% and 94% of cases following standard trabeculectomy and trabeculectomy with intraoperative antimetabolites, respectively. The total success rate using all criteria together was 76% following standard trabeculectomy and 74% following trabeculectomy with intraoperative antimetabolites.

CONCLUSION

The overall outcome after trabeculectomy is good with appropriate follow-up and timely decisions for after-treatment to ensure good development of the filtering bleb.

Difficulties in the management of an incomplete form of refractory thrombotic thrombocytopenic purpura, the usefulness of vincristine

BACKGROUND

Although several etiologies can be identified in thrombotic thrombocytopenic purpura (TTP), idiopathic cases are still frequent. Incomplete forms are more rare. Currently, the diagnosis may be made in cases of thrombocytopenia and microangiopathic hemolytic anemia. According to the literature, mortality and morbidity are significantly improved with plasma exchange. However, treatment in refractory forms remains problematic.

CASE REPORT

A 33-year old woman presented with an incomplete form of TTP, refractory to a combination of therapeutics. The patient underwent plasma infusion, plasma exchange, and then was started on corticosteroids. She also received intravenous immunoglobulins and antiplatelet agents in close proximity to vincristine (Oncovin) infusion. The main biological indicators used were the platelet count, hematocrit, LDH, and the presence of schistocytes. Following vincristine treatment, the patient's condition rapidly improved.

CONCLUSION

Vincristine administered after the failure of standard therapeutics was effective in this refractory form of TTP.

Gene therapy for murine liver cancer by adenovirus-mediated cytosine deaminase gene

OBJECTIVE

To investigate anti-tumor effects of AdCD/5FC system on mice bearing MM45T.Li liver cancer.

METHODS

IC(50), bystander effect and cell apoptosis were observed in vitro. After treatment of the tumor with AdCD in situ and injection of 5FC peritoneally into the mice, the anti-tumor effects were observed.

RESULTS

When MOI=100, AdCD infected MM45T.Li was sensitive to 5FC, and the IC(50) was less than 50 micromol/L. When 10% MM45T.Li cells were infected with AdCD, 72% cells died after 5FC treatment, which showed significant bystander effect. Through TUNEL test and Hoechst 33258 staining, it was demonstrated that there was cell apoptosis after AdCD/5FC treatment of the MM45T.Li cell 21 day after treatment of the mice bearing tumor. The tumor volume was reduced significantly (F=20.33, P<0.05), and the median survival time was prolonged from 41-43 day to 49 day.

CONCLUSION

AdCD/5FC system shows significant anti-tumor effects.

Histologic effect of mitomycin C on strabismus surgery in the rabbit

PURPOSE

To evaluate the efficiency of mitomycin C (MMC) in limiting the postoperative inflammatory response and scarring after strabismus surgery.

METHODS

A prospective, two-stage, masked, controlled trial was conducted. In the first stage, the inflammatory response at the extraocular muscle reattachment site was increased after inferior rectus recession in eight rabbits. In the second stage, MMC (0.4 mg/ml) was applied during surgery to the eyes of 22 rabbits with inferior rectus recession. As a control, contralateral eyes were treated with saline solution. Seven weeks later, exenteration was performed, and the sites of muscle reattachment were processed for histologic examinations. The sums of the areas of the granulomas in the extraocular muscle reattachment sites of control and treated eyes were compared.

RESULTS

There was no significant inhibitory effect of MMC on the inflammatory response of treated eyes compared with that of control eyes.

CONCLUSIONS

The intraoperative use of MMC (0.4 mg/ml) was not effective in controlling the postoperative inflammatory response in rabbit eyes after extraocular muscle surgery. These data do not support the hypothesis that MMC reduces postoperative adhesions after strabismus surgery.

Combined antitumor effects of an adenoviral cytosine deaminase/thymidine kinase fusion gene in rat C6 glioma

OBJECTIVE

In this study, we investigated the feasibility of a double-suicide gene/prodrug therapy, involving direct introduction of the herpes simplex virus Type 1 thymidine kinase (TK) gene and the Escherichia coli cytosine deaminase (CD) gene, via a recombinant adenoviral vector, and ganciclovir (GCV) and/or 5-fluorocytosine (5-FC) treatment, in a rat C6 glioma model.

METHODS

Efficient gene transfer and transduction of C6 glioma cells via a recombinant adenovirus were evaluated by infecting cells with adenovirus bearing the beta-galactosidase gene and then staining cells with X-5-bromo-4-chloro-3-indolyl-13-D-galactoside. CD/TK expression in cells infected with adenovirus bearing the CD/TK gene (ad-CD/TK) was examined by immunoblotting analysis. For in vitro cytotoxicity experiments, the cells were infected with ad-CD/TK or ad-deltaE1 (as a control). After the addition of a variety of concentrations of GCV and 5-FC, either separately or in combination, cell viability was determined by staining the cells with crystal violet solution 6 days after infection. For in vivo antitumor experiments, 1x10(5) cells were stereotactically injected into the right caudate-putamen of female Wistar rat brains. At 3 days after implantation, 1x10(8) plaque-forming units of ad-CD/TK or ad-deltaE1 (as a control) were stereotactically injected into the tumors and GCV (25 mg/kg) and 5-FC (250 mg/kg), alone or in combination, were intraperitoneally administered. Animals were then killed, and tumor volumes were measured by determining the tumor area in every fifth section, using a light microscope.

RESULTS

C6 glioma cells were efficiently transduced with recombinant adenoviral vector at multiplicities of infection of 200 or more. In vitro cytotoxicity of GCV and/or 5-FC, either alone or in combination, was exclusively observed in the cells transduced with ad-CD/TK. Obvious cytotoxicity (>50% inhibition) was observed in the presence of 5-FC at concentrations greater than 30 microg/ml or GCV at concentrations greater than 0.3 microg/ml at a multiplicity of infection of 100. Additionally, cytotoxicity in the presence of both GCV and 5-FC was greater than that after single-prodrug treatments, indicating additive effects of the prodrug treatments. In in vivo experiments, the tumor volumes of the rats treated with GCV or 5-FC alone after ad-CD/TK injection (59.1+/-4.6 and 57.4+/-7.1 mm3, respectively) were significantly smaller than that of the control rats (157+/-8.9 mm3, P<0.05). Furthermore, the tumor volume of the rats treated with GCV and 5-FC in combination was 14.7+/-1.8 mm3.

CONCLUSION

These results demonstrated the efficient transduction of C6 glioma cells with a recombinant adenovirus and the additive effects of CD/TK fusion gene/GCV/5-FC treatment, compared with single-gene therapy with the TK or CD gene. Therefore, our data suggest that the direct administration of a double-suicide gene/prodrug therapy has great potential in the treatment of brain tumors.

Allopurinol in addition to 5-aminosalicylic acid based drugs for the maintenance treatment of ulcerative colitis

BACKGROUND

To investigate the value of combined treatment with allopurinol and 5-aminosalicylic (5-ASA) based drugs as maintenance treatment for ulcerative colitis (UC).

METHODS

199 patients with UC in remission but with active disease during the preceding 3 years were included. Allopurinol 100 mg twice daily or placebo was added to the 5-ASA based maintenance treatment. Clinical and endoscopic follow up was performed after 1, 6 and 12 months.

RESULTS

Intention-to-treat analysis after 6 and 12 months showed similar results in both groups. A log-rank test showed that 77% in the allopurinol compared to 59% in the placebo group were still in remission after 6 months (P=0.0083) and 62% and 53% after 12 months, respectively (P=0.0936). This was mainly due to a higher than expected number of relapses during the first 3 months in the placebo group. After the first 3 months, the rate of relapse in each group was similar.

CONCLUSIONS

It appears possible that allopurinol in combination with 5-ASA is better than 5-ASA alone for a 6-month, but not a 12-month period. This has to be verified in further dose-ranging studies.

Doses and time-dependent effects of 3'-azido-3'-deoxythymidine on T47D human breast cancer cells in vitro

The objective of the present work was to study the effects of 3'-azido-3'-deoxythymidine (azidothymidine, Zidovudine) on human breast cancer cells by using, as a model, the T47D cell line (typified as oestrogen-dependent and p53-mutated). Low azidothymidine doses (3.125 microM) increase the percentage of cells in S-phase, with the effect reversing after 24 hr of incubation; as azidothymidine doses increase, the magnitude and duration of its effect increase proportionally, although, even with the highest concentrations (50-100 microM) the effects decline after 48 hr of incubation. If media (containing azidothymidine or vehicle) are daily renewed, the azidothymidine effects (accumulation of cells in S-phase) are higher and decline later than when media and drug are not changed during the whole culture period, thereby suggesting that the reversion of azidothymidine effects could be related with a degradation of the drug or accumulation in media of substances which counteract its effects. Azidothymidine inhibits T47D cell proliferation at concentrations higher than 50 microM. The exposure to 50 or 100 microM azidothymidine induced cell apoptosis after 48 hr or more of incubation. We conclude that: a) azidothymidine, with appropriate doses and duration of treatment, synchronizes cells in S-phase, inhibits proliferation, and induces apoptosis, b) the discontinuous application of the drug rather than continuous exposure to it increases its efficiency to synchronize the T47D cell cycle. This in vitro anti-breast cancer activity suggests that a possible clinical usefulness of azidothymidine, either alone or associated with other drugs with cycle-specific antitumoural activity circumscribed to the S-phase of cell cycle, is worthy of investigation.

Vidarabine and 2-deoxycoformycin as antileukemic agents against monocytic leukemia

Although 2'-deoxycoformycin (dCF) has been reported in clinical trials to be less effective against myeloid than lymphoid malignancies, it may be useful for treating monocytic leukemia with the aid of 2'-deoxyadenosine (dAd) analogs. In the presence of 10 microM dAd, the concentration of dCF required to inhibit the viability of monocytoid leukemia cells was much lower than that required on normal or non-monocytoid malignant cells in primary culture. Among the dAd analogs, 9-beta-D-arabinofuranosyladenine (AraA) was also effective in combination with dCF. Although dCF alone slightly but significantly prolonged the survival of mice inoculated with U937 monocytic leukemia cells, combined treatment with dCF and AraA markedly prolonged the survival. These results suggest that the combination of dCF and AraA may be useful for the clinical treatment of acute monocytic leukemia.

Antileukemic efficacy of 2-deoxycoformycin in monocytic leukemia cells

2'-Deoxycoformycin (dCF) as a single agent has been reported to be less effective against myeloid than against lymphoid malignancies in clinical trials. However, previous studies have shown that in the presence of 2'-deoxyadenosine (dAd), human monocytoid leukemia cell lines are much more sensitive to dCF with regard to the inhibition of cell proliferation. Thus, dCF might be useful for treating monocytoid leukemia with the aid of dAd analogs. The antiproliferative effects of dCF in combination with dAd or its derivatives were examined on normal and malignant blood and bone marrow cells. In the presence of 10 micromol/L dAd, the concentration of dCF required to inhibit the viability of primary monocytoid leukemia cells was much lower than that required to inhibit normal or non-monocytoid leukemic cells. Among the dAd analogs, 9-beta-D-arabinofuranosyladenine (AraA) was also effective in combination with dCF. Athymic nude mice were inoculated with human monocytoid leukemia U937 cells and treated with dCF or a dAd analog or both. Although dCF alone slightly but significantly prolonged the survival of mice inoculated with U937 cells, combined treatment with dCF and AraA markedly prolonged their survival. These data suggest that the combination of dCF and AraA may be useful for the clinical treatment of acute monocytic leukemia. (Blood. 2000;96:1512-1516)

Modern immunosuppression

The current treatment of posttransplant lymphoproliferative disease (PTLD) includes prophylaxis at the time of transplant, decreasing or stopping immunosuppresion and initiation of antiviral therapy in patients with polymerase chain reaction or clinical evidence of PTLD, and judicial reintroduction of immunosuppression in patients who have cleared their PTLD and have begun to have rejection. The pharmacology, pharmacokinetics, notable side effects, and toxicities of the immunosuppressive agents are described in this article. At the conclusion of each section the author's current practice with these agents and treatment strategies are described.

[Vaccination by suicide gene therapy against a model of hepatic metastasis from colon cancer in the rat]

Suicide gene therapy consists of transferring into tumor cells a viral or bacterial gene encoding for an enzyme which converts a non-toxic product into a lethal drug.

STUDY AIM

To analyze the therapeutic potential of vaccination with tumor cells expressing the bacterial cytosine deaminase (CD) gene and 5-fluorocytosine (5-FC) treatment in a rat liver metastasis model.

MATERIAL AND METHOD

We used a rat colon carcinoma cell line which, after subcapsular or intraportal injection in syngenic animals, generates single or multiple experimental liver metastases, respectively. We have shown that introduction of a vector expressing the CD gene in this colon carcinoma cell line results in 5-FC sensitivity (PRObCD).

RESULTS

Intrahepatic subcapsular injection of PRObCD tumor cells, followed by 5-FC treatment, induces total regression of a wild-type tumor pre-established in the contralateral liver lobe in 45% of animals with a 96% decrease in mean volume (p < 0.0001), demonstrating the existence of a distant bystander effect. This vaccination significantly increased the survival of rats with single (log-rank p < 0.0001) or multiple (log-rank p = 0.01) liver metastasis

CONCLUSIONS

These results suggest that suicide gene-modified tumor cells can act as potent therapeutic vaccines against liver metastasis from colon carcinoma.

Topical tretinoin and 5-fluorouracil in the treatment of linear verrucous epidermal nevus

Treatment of a linear verrucous epidermal nevus using topical 0.1% tretinoin cream and 5% 5-fluorouracil in a young patient is described. In 1994, successful topical therapy using this combination was described in the management of an inflammatory linear verrucous epidermal nevus. We report another case in which treatment of a noninflamed epidermal verrucous nevus with 0.1% tretinoin and 5% 5-fluorouracil resulted in significant improvement. An updated summary of the literature discussing management of epidermal nevi is presented.

[The study on the anti-osteoporosis effect of clodronate in ovariectomized rats]

To evaluate the anti-osteoporosis effect of clodronate in ovariectomized rats, 44 female Wistar rats, aged 8 months, were divided randomly into 4 groups: the SHAM group (subjected to sham operation); the OVX group (subjected to bilateral ovariectomy); the E3 group (subjected to bilateral ovariectomy and treated after surgery with nilestriol 1 mg/kg BW by gavage once a week for 12 weeks), and the clodronate group (subjected to bilateral ovariectomy and treated after surgery with clodronate 5 mg/kg BW by subcutaneous injection twice a week for 12 weeks). All the animals were sacrificed 12 weeks after the operation. The blood and urine samples were collected for determination of biochemical indices. The humeri and tibiae were prepared for determination of net weight, ash weight, calcium and phosphorus content, bone density, as well as bone histopathology and histomorphometry. The left femora were processed for bone anti-curve power. The results showed that as compared with the SHAM group, the net weight, ash weight, calcium content, density and anti-curve power of bones, te trabecular bone volume and thickness were all significantly reduced in the OVS group, while its osteoblast index, osteoclast index and urine hydroxyproline content were obviously close to normal levels. The data indicates that both clodronate and E3 can effectively prevent bone loss in ovariectomized rats.