Intraarterial delivery of adenovirus vectors and liposome-DNA complexes to experimental brain neoplasms.

This study investigated the intraarterial delivery of genetically engineered replication-deficient adenovirus vectors (AVs) and cationic liposome-plasmid DNA complexes (lipoDNA) to experimental brain tumors. Adenovirus or lipoDNA was injected into the internal carotid artery (ICA) of F344 rats harboring intracerebral 9L gliosarcomas, using bradykinin (BK) to selectively permeabilize the blood-tumor barrier (BTB). Brain and internal organs of the animals were collected 48 hr after vector injection and stained for expression of the marker gene product, beta-galactosidase (beta-Gal). Intracarotid delivery of AV to 9L rat gliosarcoma without BTB disruption resulted in transgene expression in 3-10% of tumor cells distributed throughout the tumor. Virus-mediated expression of beta-gal gene products in this tumor model was particularly high in small foci (< or = 0.5 mm), which had invaded the normal brain tissue surrounding the main tumor mass. In these foci more than 50% of tumor cells were transduced. BK infusion increased the amount of transgene-expressing cells in larger tumor foci to 15-30%. In the brain parenchyma only a few endothelial cells expressed beta-gal owing to AV-mediated gene transfer. Intracarotid delivery of lipoDNA bearing a cytoplasmic expression cassette rendered more than 30% of the tumor cells positive for the marker gene without BTB disruption. The pattern of distribution was in general homogeneous throughout the tumor. BK infusion was able to increase further the number of transduced tumor cells to more than 50%. Although lipoDNA-mediated gene transfer showed increased efficacy as compared with AV-mediated gene transfer, it had less specificity since a larger number of endothelial and glial cells also expressed the transgene. AV and lipoDNA injections, in the absence and presence of BK, also resulted in transduction of peripheral organs. AV showed its known predilection for liver and lung. In the case of lipoDNA, parenchymal organs such as liver, lung, testes, lymphatic nodes, and especially spleen, were transduced. These findings indicate that intracarotid application of AV and lipoDNA vectors can effectively transduce tumor cells in the brain, and that BTB modulation by BK infusion can further increase the number of transgene-expressing tumor cells.

Selective delivery of herpes virus vectors to experimental brain tumors using RMP-7.

RMP-7, a bradykinin analog, has been shown to selectively open the blood-tumor barrier for the delivery of chemotherapeutic drugs to brain tumors. In contrast to bradykinin, RMP-7 has no hypotensive effects and has been approved for human use. This study was initiated to determine whether RMP-7 would open the blood-tumor barrier to virus vectors encoding tumor-killing genes in an experimental model. The herpes virus vector used, hrR3, which encodes virus thymidine kinase gene and the lacZ reporter gene, is defective in a gene encoding ribonucleotide reductase, replicates selectively in dividing tumor cells and not in postmitotic neural cells. It was determined that an optimum dose of RMP-7 (1.5-3.0 microg/kg over 10-15 minutes) enhanced viral delivery to brain tumors in rats bearing intracranial 9 L gliosarcomas when infused through the carotid artery immediately prior to virus vector application. Maximum expression of the lacZ reporter gene occurred at 3 days after intracarotid infusion. By 8 days, transgene expression was largely confined to tumor foci away from the main tumor mass. Viral delivery was essentially specific to tumor cells, with little transgene expression elsewhere in the brain. Minimal uptake and pathology was noted in the kidney, spleen, and liver. These findings indicate that intracarotid delivery of RMP-7 can augment the selective delivery of virus vectors to brain tumors in an experimental rat model, with the potential for application to human brain tumors.

Multicolumn infusion of gene therapy cells into human brain tumors: technical report.

OBJECTIVE: Effective gene therapy for brain tumors may require saturation of the tumors with tumoricidal doses of the therapeutic gene. Safe, precise, and efficient delivery of gene therapy vectors is required. Most reported cases of and published protocols for gene therapy for brain tumors involve freehand injection of retroviral vector-producing cells (VPCs) into the brain. Major disadvantages of this method include the inaccuracy of hand-guided needle placement and limited control of injection parameters. These factors can result in failure to deliver the viral vectors to specifically targeted sites within the brain, extensive tissue disruption resulting from excessively forceful injection, and reflux of the injectate along the needle tract. METHODS: We describe a novel stereotactic strategy for saturating tumor volumes with tumoricidal doses of gene therapy vectors and a new, more precise method of infusing VPCs. With our new instrument, the multicolumn stereotactic infusion system, needle placement is stereotactically guided and both VPC infusion and needle withdrawal are mechanically controlled. RESULTS: This technique, which has been used effectively for six patients, permits precise deposition of columns of VPCs throughout the targeted tumor volume. CONCLUSION: This technique should facilitate saturation of tumors with tumoricidal doses of gene therapy vectors and should improve the results of gene therapy protocols that rely on intraparenchymal injection for delivery.

Thymidine kinase activation of ganciclovir in recurrent malignant gliomas: a gene-marking and neuropathological study.

OBJECT: The gene therapy paradigm of intratumoral activation of ganciclovir (GCV) following transduction of tumor cells by retroviral vectors bearing the thymidine kinase (tk) gene has produced dramatic remissions of malignant gliomas in animal models. In human trials, although the technique has been deemed safe, little antitumor effect has been demonstrated. To evaluate the basis of this inefficacy in human gliomas, the authors conducted a gene-marking trial involving neuropathological and biochemical studies of treated tumor specimens. METHODS: Five patients with malignant recurrent gliomas underwent stereotactic biopsy sampling and intratumoral implantation procedures with three aliquots of 10(6) vector-producing cells (VPCs) in columns. After 5 days, the tumor was resected and the tumor bed reimplanted with VPCs, and a course of GCV was given. Patients received clinical and radiological follow up for 6 months. Tumor specimens were analyzed neuropathologically and for tk gene expression by anti-TK immunohistochemistry and TK enzymatic activity. Four patients tolerated the treatment well but experienced tumor progression. The other developed an abscess after the second operation and died. Increased TK enzymatic activity was demonstrated in the one tumor specimen analyzed. Immunohistochemical evidence of tk gene expression was limited to VPCs. Transduction of tumor cells was not seen. Viable tumor cells were seen near VPCs containing TK. The lymphocytic immune response was mild. CONCLUSIONS: Except for the risk of infection inherent in reoperation, this tk-GCV paradigm was both feasible and safe. Pathological studies indicated that limited dissemination of VPCs and vector from the infusion site and failure to transduce tumor cells with the tk gene are major barriers to efficacy.

Trichobezoar--a condition to think of in case of mobile abdominal mass.

A twenty year old girl was referred to the surgical out-patients clinic with a history of intermittent epigastric pain and vomiting of five months duration. The patient enjoyed good health prior to this and her past medical history was uneventful. Findings on physical examination included pallor, patchy alopecia and a soft mobile, non-tender mass in the epigastrium and left upper quadrant of the abdomen. When questioned she admitted to a history of trichophagia for as long as she could recall. A provisional diagnosis of gastric trichobezoar was made. Radiological investigations included an abdominal ultrasound which showed a large ill-defined mass lesion with poor transonic features, situated in the upper abdomen and extending from the left upper quadrant across the midline to the liver margin. Barium meal revealed that the greater part of the lumen of stomach was occupied with material of an indeterminate nature. Her haematological investigations showed Haemoglobin 9.5 gm/dl and Leucocyte Count 9.0 x 10(9)/L. Her Urea and Electrolytes were within normal range. At laparotomy a large hair ball extending from the Stomach into the duodenum and proximal jejunum was removed through a vertical gastrotomy incision. The patient had a satisfactory post-operative convalescence and was discharged two weeks later.

A review of gene therapy for the treatment of central nervous system tumors.

The transfer of genes into tumors of the central nervous system has been touted as a novel treatment. However, several scientific and technological hurdles will have to be resolved before such strategies become useful clinical tools. This review summarizes the current knowledge in the field. Some of the gene delivery vectors employed both preclinically and clinically are those based on retroviruses, herpes simplex viruses, adenoviruses, adeno-associated viruses, and reoviruses. Cells such as fibroblasts and neural progenitor cells may also provide therapeutic value. These vectors are used to deliver into the tumor cell a variety of anticancer genes, such as those that activate chemotherapy agents, increase tumor immunogenicity, modulate tumor apoptosis and/or angiogenesis. One of the issues confronting such therapeutic strategies revolves around the blood-brain-barrier that may limit the penetration of vectors and genes form the circulation into the tumor. Results from a variety of clinical trials are becoming available. While the safety of this treatment strategy appears to have been established, therapeutic efficacy has been lacking. Additional refinements in the basic technology of vector construction and further understanding of the basic biology of gene transfer and expression will help in establishing gene therapy as clinically useful against brain tumors.

Intracranial meningiomas: analysis of recurrence after surgical treatment.

Recurrence of intracranial meningiomas after surgery has long been recognized, but there is still no consensus about factors responsible for recurrence. To better understand such factors, we analysed data on 276 patients with meningiomas who were treated at our institution from 1976 to 1990 (mean follow-up = 5.1 years). Effects of sex, tumour histology, tumour site, and radiotherapy on recurrence were closely studied. Using World Health Organization criteria to define malignancy, 254 of the tumours were benign and 22 were atypical or malignant. For data analysis, distinction was made between "recurrence"(i.e., reappearance of tumour after total resection) and "regrowth" (i.e., tumour enlargement after subtotal removal). Recurrence was seen in 2 of 183 benign meningiomas and in 10 of 16 malignant meningiomas. Recurrence and regrowth rates for malignant meningiomas far exceeded those for benign meningiomas (p = 0.001). Neither sex nor tumour site was associated with subsequent recurrences in patients whose tumours had been completely resected. The influence of radiotherapy was studied in terms of its effects on benign versus malignant meningiomas, whether given after complete or incomplete resection, and whether given after primary resection or on reoperation. We found that radiotherapy did not decrease "recurrence" or "regrowth" regardless of when administered, either at first resection or on recurrence. This was true for benign as well as malignant meningiomas. However, due to the small number in our series, we cannot conclude that radiotherapy has no beneficial role in the treatment of meningiomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Psoas abscess secondary to discitis: a case report of conservative management.

We report a case of secondary psoas abscess in a 37-year-old man with a 3-week history of severe low backache managed conservatively without surgical drainage. Apart from bilaterally restricted straight leg raising (<70 degrees), his neurologic examination was within normal limits. Magnetic resonance imaging showed discitis of the L3-L4 space and a left-sided secondary psoas abscess. Aspiration biopsy of the abscess material under radiologic control isolated Staphylococcus aureus, which responded to appropriate antibiotic therapy with complete resolution. A high index of suspicion is necessary for diagnosis of psoas abscess, which should be considered in patients with pyrexia and backache with a neurologic examination that is otherwise normal. We discuss the recommendations for surgical and nonsurgical approaches.