The second-look operation improves survival in suboptimally debulked stage III ovarian cancer patients

In a single-institution retrospective cohort study, 230 patients were treated for stage III primary ovarian cancer and 175 became eligible for second-look operations by virtue of a complete clinical response after primary surgical cytoreduction and platinum-based combination chemotherapy. Of these, 109 underwent a second-look operation. Optimal primary cytoreduction was defined as residual disease < or =1 cm. Median follow-up was 68.3 months. Five-year survival for all the 230 stage III ovarian cancers was 43.4%. Among all eligible patients (n = 175), there was no survival difference (P = 0.67) in those having second look (57.3%, 5-year survival) versus no second look (48.7%). In those patients with optimal primary cytoreduction (n = 118), there was no survival advantage to second look (69% versus 61%, P = 0.7). However, in those with suboptimal primary cytoreduction (n = 47), 5-year survival was 36% in those having second look versus only 13% in those refusing second look (P < 0.05). Multivariate analysis identified second-look surgery as the only significant independent prognostic variable affecting survival (RR = 0.321, P < 0.04). Patients with suboptimal debulking at primary surgery for stage III ovarian cancer appear to achieve a survival benefit from second-look surgical procedures, presumably from the early identification and treatment of residual disease.

Long-term treatment with subcutaneous T-20, a fusion inhibitor, in HIV-infected patients: patient satisfaction and impact on activities of daily living

T-20 is a novel antiretroviral agent that inhibits the fusion of human immunodeficiency virus (HIV) with target cell membranes. It is delivered by self-administered, twice-daily, subcutaneous injections. The impact of this mode of administration on patients' ability to conduct normal activities of daily living (ADL) and comply with a T-20 treatment regimen was assessed as part of a 48-week, phase 2 trial (T20-205). Patients' opinions on the impact of T-20 on ADL, ease of use of T-20, and choice to continue with T-20 were assessed by two questionnaires completed at baseline and week 48 (or study withdrawal). ADL were measured using a Likert-type scale based on established instruments with questions added to assess HIV-specific issues. Seventy previously treated patients received T-20 in combination with an average of five oral antiretroviral agents. Relative to other HIV/AIDS drugs, T-20 had little impact on ADL, with the majority of patients (54%-96%) agreeing (somewhat or strongly) that subcutaneous injections had not limited ADL. Patients found the injections relatively easy to perform with more than 47% of patients stating that each aspect of the injections (ease of injection, storage, reconstitution, and disposal of sharps) were very easy or easy. If medically indicated, 98% of patients stated that they would choose to continue with T-20. The most common reasons for this were the perceived effectiveness of T-20 and lack of side effects. In conclusion, the need to deliver T-20 via twice-daily subcutaneous injections was not considered an important barrier by HIV-positive patients seeking improvement or stabilization of their condition.

The coxsackievirus and adenovirus receptor is a transmembrane component of the tight junction

The coxsackievirus and adenovirus receptor (CAR) mediates viral attachment and infection, but its physiologic functions have not been described. In nonpolarized cells, CAR localized to homotypic intercellular contacts, mediated homotypic cell aggregation, and recruited the tight junction protein ZO-1 to sites of cell-cell contact. In polarized epithelial cells, CAR and ZO-1 colocalized to tight junctions and could be coprecipitated from cell lysates. CAR expression led to reduced passage of macromolecules and ions across cell monolayers, and soluble CAR inhibited the formation of functional tight junctions. Virus entry into polarized epithelium required disruption of tight junctions. These results indicate that CAR is a component of the tight junction and of the functional barrier to paracellular solute movement. Sequestration of CAR in tight junctions may limit virus infection across epithelial surfaces.

Multiple regions within the coxsackievirus and adenovirus receptor cytoplasmic domain are required for basolateral sorting

The coxsackievirus and adenovirus receptor (CAR) mediates attachment and infection by coxsackie B viruses and many adenoviruses. In human airway epithelia, as well as in transfected Madin-Darby canine kidney cells, CAR is expressed exclusively on the basolateral surface. Variants of CAR that lack the cytoplasmic domain or are attached to the cell membrane by a glycosylphosphatidylinositol anchor are expressed on both the apical and basolateral surfaces. We have examined the localization of CAR variants with progressive truncations of the cytoplasmic domain, as well as with mutations that ablate a potential PDZ (PSD95/dlg/ZO-1) interaction motif and a putative tyrosine-based sorting signal. In addition, we have examined the targeting of two murine CAR isoforms, with different C-terminal sequences. The results suggest that multiple regions within the CAR cytoplasmic domain contain information that is necessary for basolateral targeting.

Critical role for CD8 in binding of MHC tetramers to TCR: CD8 antibodies block specific binding of human tumor-specific MHC-peptide tetramers to TCR

There are conflicting opinions about the role that the T cell coreceptors CD4 and CD8 play in TCR binding and activation. Recent evidence from transgenic mouse models suggests that CD8 plays a critical role in TCR binding and activation by peptide-MHC complex multimers (tetramers). Here we show with a human CTL clone specific for a tumor-associated MHC-peptide complex that the binding of tetramers to the TCR on these cells is completely blocked by anti-human CD8 Abs. Moreover, the staining of CTLs with specific MHC-peptide tetramers simultaneously with anti-CD8 Abs was completely blocked with three different anti-CD8 Abs. This blockage was mediated by anti-CD8 Abs but not anti-CD3 Abs and was dose dependent. The blocking effect of the anti-CD8 Abs was attributable to directly inhibiting tetramer binding and was not attributable to Ab-mediated TCR-CD8 internalization and down-regulation. Our results have important implications in TCR binding to MHC-peptide tetramers. MHC-peptide tetramers are widely used today in combination with anti-CD8 Abs for the phenotypic analysis of T cell populations and in the study of T cell responses under various pathological conditions such as infectious diseases and cancer. Our results indicate that also in the human system CD8 plays a critical role in the interaction of MHC-peptide multimers with TCR.

Use of genotypic resistance testing to guide hiv therapy: clinical impact and cost-effectiveness

BACKGROUND

Genotypic sequencing for drug-resistant strains of HIV can guide the choice of antiretroviral therapy.

OBJECTIVE

To assess the cost-effectiveness of genotypic resistance testing for patients acquiring drug resistance through failed treatment (secondary resistance) and those infected with resistant virus (primary resistance).

DESIGN

Cost-effectiveness analysis with an HIV simulation model incorporating CD4 cell count and HIV RNA level as predictors of disease progression.

DATA SOURCES

Published randomized trials and data from the Multicenter AIDS Cohort Study, the national AIDS Cost and Services Utilization Survey, the Red Book, and an institutional cost-accounting system.

TARGET POPULATION

HIV-infected patients in the United States with baseline CD4 counts of 0.250 x 10(9) cells/L.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTIONS

Genotypic resistance testing and clinical judgment, compared with clinical judgment alone, in two contexts: after initial treatment failure (secondary resistance testing) and before initiation of antiretroviral therapy (primary resistance testing).

OUTCOME MEASURES

Life expectancy, quality-adjusted life expectancy, and cost-effectiveness in dollars per quality-adjusted life-year (QALY) gained.

RESULTS OF BASE-CASE ANALYSIS

Secondary resistance testing increased life expectancy by 3 months, at a cost of $17 900 per QALY gained. The cost-effectiveness of primary resistance testing was $22 300 per QALY gained with a 20% prevalence of primary resistance but increased to $69 000 per QALY gained with 4% prevalence.

RESULTS OF SENSITIVITY ANALYSIS

The cost-effectiveness ratio for secondary resistance testing remained under $25 000 per QALY gained, even when effectiveness and cost of testing and antiretroviral therapy, quality-of-life weights, and discount rate were varied.

CONCLUSIONS

Genotypic antiretroviral resistance testing following antiretroviral failure is cost-effective. Primary resistance testing also seems to be reasonably cost-effective and will become more so as the prevalence of primary resistance increases.

The cost effectiveness of combination antiretroviral therapy for HIV disease

BACKGROUND

Combination antiretroviral therapy with a combination of three or more drugs has become the standard of care for patients with human immunodeficiency virus (HIV) infection in the United States. We estimated the clinical benefits and cost effectiveness of three-drug antiretroviral regimens.

METHODS

We developed a mathematical simulation model of HIV disease, using the CD4 cell count and HIV RNA level as predictors of the progression of disease. Outcome measures included life expectancy, life expectancy adjusted for the quality of life, lifetime direct medical costs, and cost effectiveness in dollars per quality-adjusted year of life gained. Clinical data were derived from major clinical trials, including the AIDS Clinical Trials Group 320 Study. Data on costs were based on the national AIDS Cost and Services Utilization Survey, with drug costs obtained from the Red Book.

RESULTS

For patients similar to those in the AIDS Clinical Trials Group 320 Study (mean CD4 cell count, 87 per cubic millimeter), life expectancy adjusted for the quality of life increased from 1.53 to 2.91 years, and per-person lifetime costs increased from $45,460 to $77,300 with three-drug therapy as compared with no therapy. The incremental cost per quality-adjusted year of life gained, as compared with no therapy, was $23,000. On the basis of additional data from other major studies, the cost-effectiveness ratio for three-drug therapy ranged from $13,000 to $23,000 per quality-adjusted year of life gained. The initial CD4 cell count and drug costs were the most important determinants of costs, clinical benefits, and cost effectiveness.

CONCLUSIONS

Treatment of HIV infection with a combination of three antiretroviral drugs is a cost-effective use of resources.

Antibody engineering for targeted therapy of cancer: recombinant Fv-immunotoxins

Recombinant Fv-immunotoxins are a new class of biologic anticancer agents composed of a recombinant antibody fragment linked to a very potent bacterial toxin. These potent molecules are designed to specifically bind and kill cancer cells that express a specific target antigen on their cell surface. Recombinant Fv-immunotoxins are an excellent example for the concept of rational drug design. They combine the progress in understanding cancer biology, -the recent knowledge on the mechanisms of malignant transformation and the special properties of cancer cells, -with the enormous developments in recombinant DNA technology and antibody engineering. Recombinant Fv immunotoxins were developed for solid tumors and hematological malignancies and have been characterized intensively for their biological activity in vitro and in vivo in animal models. The excellent in vitro and in vivo activities of recombinant Fv-immunotoxins have lead to their pre-clinical development and to the initiation of clinical trial protocols. Recent trials have demonstrated potent clinical efficacy in patients with malignant diseases that are refractory to traditional modalities of cancer treatment. It is thus suggested that this strategy can be developed into a separate modality of cancer treatment with the basic rationale of specifically targeting cancer cells on the basis of their unique surface markers combined with potent effective biological toxic agents that directly kill the cancer cell. Efforts are now being made to improve the current molecules and to develop new agents with better clinical efficacy. In this review, we will describe the rationale in designing Fv-immunotoxins and will review current progress made in using these agents for cancer treatment.

Drug-resistant Drosophila indicate glutamate-gated chloride channels are targets for the antiparasitics nodulisporic acid and ivermectin

The fruit fly Drosophila melanogaster was used to examine the mode of action of the novel insecticide and acaricide nodulisporic acid. Flies resistant to nodulisporic acid were selected by stepwise increasing the dose of drug in the culture media. The resistant strain, glc(1), is at least 20-fold resistant to nodulisporic acid and 3-fold cross-resistant to the parasiticide ivermectin, and exhibited decreased brood size, decreased locomotion, and bang sensitivity. Binding assays using glc(1) head membranes showed a marked decrease in the affinity for nodulisporic acid and ivermectin. A combination of genetics and sequencing identified a proline to serine mutation (P299S) in the gene coding for the glutamate-gated chloride channel subunit DmGluClalpha. To examine the effect of this mutation on the biophysical properties of DmGluClalpha channels, it was introduced into a recombinant DmGluClalpha, and RNA encoding wild-type and mutant subunits was injected into Xenopus oocytes. Nodulisporic acid directly activated wild-type and mutant DmGluClalpha channels. However, mutant channels were approximately 10-fold less sensitive to activation by nodulisporic acid, as well as ivermectin and the endogenous ligand glutamate, providing direct evidence that nodulisporic acid and ivermectin act on DmGluClalpha channels.

Recombinant human single-chain MHC-peptide complexes made from E. coli By in vitro refolding: functional single-chain MHC-peptide complexes and tetramers with tumor associated antigens

Soluble recombinant MHC-peptide complexes are valuable tools for molecular characterization of immune responses as well as for other functional and structural studies. In this study, soluble recombinant single-chain human MHC (scMHC)-peptide complexes were generated by in vitro refolding of inclusion bodies from bacterially expressed engineered HLA-A2 in the presence of tumor-associated or viral peptides. The scMHC molecule was composed of beta2-microglobulin connected to the first three domains of the HLA-A2 heavy chain through a 15-amino acid flexible linker. Highly purified scMHC-peptide complexes were obtained in high yield using several peptides derived from the melanoma antigens gp100 and MART-1 or a viral peptide derived from HTLV-1. The scMHC complexes were characterized in detail and were found to be correctly folded and able to specifically bind HLA-A2-restricted peptides. We also generated scMHC-peptide tetramers, which were biologically functional; they induced a peptide-specific CTL clone to be activated and secrete IFN-gamma, and were able to stain specifically CTL lines. Such recombinant soluble scMHC-peptide complexes and tetramers should prove of great value for characterization of immune responses involving CTL, for visualization of antigen-specific immune responses, for in vitro primary CTL induction, and for peptide binding assays and structural studies.

Low-dose daily subcutaneous interleukin-2 in combination with highly active antiretroviral therapy in HIV+ patients: a randomized controlled trial

PURPOSE

Previous studies with intermittent interleukin-2 (IL-2) therapy using intermediate and high levels of IL-2 have demonstrated significant increases in the CD4 + T cell count in HIV-infected patients. Intermittent regimens are amenable to outpatient use, but severe adverse events are frequently experienced with intermediate- and high-dose levels of IL-2. Therefore in this study, the effect of daily, subcutaneous low-dose IL-2 therapy on safety and immunological endpoints was investigated to determine whether immunological benefit could be achieved without toxicity in HIV-infected patients also receiving highly active antiretroviral therapy (HAART).

METHOD

A total of 115 patients were enrolled in the trial. Fifty-six asymptomatic HIV-infected patients who had CD4 + T cell counts less than 300 cells/microL at screening and a stable HIV viral load received low-dose IL-2 (1.2 million IU [MIU]/m 2 beginning dose) once daily in conjunction with HAART (IL-2 group). Fifty-nine patients received HAART alone (control group).

RESULTS

A dramatic effect of IL-2 on the natural killer (NK) cell population was observed with mean increases of 156 cells/microL in the IL-2 group compared to 19.93 cells/microL in the control group (p <.001). Additionally, IL-2-treated patients experienced a statistically significant increase in the mean percentage of CD4 + T cells (3.52% increase) when compared to control patients (1.33% increase) (p <.001). The expanded CD4 + T cell population was primarily of the naive phenotype, with mean increases of 4.53% for the IL-2 group and 0.31% for the control group (p <.001 for between-group difference). In addition, a higher proportion of IL-2-treated patients (67%) compared to control patients (33%) achieved increases of greater than 50% in the CD4+ T cell count (p =.08). Adverse events of grade 3 or grade 4 toxicity were infrequent in the current study and were substantially lower by comparison to those in studies of intermittent dose IL-2 therapy. Also, negligible changes in the HIV viral load from baseline to final measurement were observed in both groups. A trend toward a reduced number of modifications of antiretroviral therapy was apparent in the IL-2 group when compared to control patients.

CONCLUSION

Daily, low-dose subcutaneous IL-2 therapy in conjunction with HAART is safe and well tolerated and is effective in expanding lymphocyte cell types including NK cells and naive T cells in individuals who have <300 CD4+ T cells.

Retroviral rebound syndrome after cessation of suppressive antiretroviral therapy in three patients with chronic HIV infection

BACKGROUND

Although viral rebound follows cessation of suppressive antiretroviral therapy in chronic HIV infection, a viremic clinical syndrome has not been described.

OBJECTIVE

To describe a retroviral syndrome associated with cessation of effective antiretroviral therapy in chronic HIV infection.

DESIGN

Case reports.

SETTING

Outpatient HIV specialty clinics in Seattle, Washington, and Boston, Massachusetts.

PATIENTS

Three patients with chronic HIV infection who discontinued suppressive antiretroviral therapy.

MEASUREMENTS

Clinical course, plasma HIV RNA levels, and CD4 cell counts before, during, and after cessation of antiretroviral therapy.

RESULTS

Within 6 weeks after stopping antiretroviral therapy, each patient experienced a clinical illness that resembled a primary HIV syndrome. This coincided with a marked increase in HIV RNA level and, in two of three patients, a decrease in CD4 cell count. After antiretroviral therapy was restarted, each patient's symptoms rapidly resolved in association with resuppression of HIV RNA and increase in CD4 cell count or percentage.

CONCLUSION

A retroviral rebound syndrome similar to that seen in primary HIV syndrome can occur in patients with chronic HIV infection after cessation of suppressive antiretroviral therapy.

Efficacy of nelfinavir in patients switched from ritonavir/saquinavir combination antiretroviral therapy

Based on available data and expert opinion, the IAS-USA treatment guidelines recommend "selective substitution" of the medication thought most likely to be causing a side effect for one that should have a different side effect profile.

PURPOSE

This study evaluates the short-term virological efficacy of selective substitution with nelfinavir-nucleoside combination therapy in individuals with plasma viral RNA below 400 copies/mL.

METHOD

This study involved a retrospective chart review at five large urban HIV Clinical practice settings and included 19 patients taking combination therapy including ritonavir with saquinavir. We performed selective substitution with a nelfinavir combination. Our main outcome measure was plasma HIV-1 RNA (Amplicor) obtained during the period between weeks 12 to 18.

RESULTS

We identified 19 HIV-1-infected individuals with evidence of viral suppression as defined by a viral load below 400 copies/mL while taking dual nucleoside reverse transcriptase inhibitors with ritonavir/saquinavir. Reasons for switching included adverse effects (37%) or preference for nelfinavir due to the possibility of a better defined salvage regimen (63%). We defined a composite viral endpoint indicative of continued viral suppression using the first 12 to 18 weeks following the medication change. We found that 73% maintained undetectable viral loads (plasma HIV RNA below 400 copies/mL) during this period.

CONCLUSION

These data suggest that any medication adjustment should be made cautiously, as there may be some potential risk in a substitution. Selective substitution of a medication that has undesirable side effects or other characteristics should be considered when the possible risks of the loss of viral suppression are outweighed by the potential benefits of that substitution.

Founder BRCA 1 and 2 mutations among a consecutive series of Ashkenazi Jewish ovarian cancer patients

OBJECTIVE

The purpose of this study was to describe the incidence of the three Ashkenazi Jewish founder genetic BRCA 1 and 2 mutations among an unselected, consecutive group of Ashkenazi Jewish ovarian cancer patients.

MATERIALS AND METHODS

From 7/30/96 to 4/12/99, 92 Ashkenazi Jewish patients with histologically confirmed epithelial ovarian cancer had surgery. All of these patients had DNA extracted from 5-microm sections of their paraffin-embedded surgical specimen tissue blocks using the Qiagen QIAamp tissue extraction kit. A multiplex (triplex) polymerase chain reaction was performed to amplify fragments for the 185delAG, 5382insC, and 6174delT mutations. The products were hybridized with normal and mutant probes for each of the three mutations. All clinical data were collected retrospectively and statistical significance was evaluated using the chi(2) test or a two-tailed Fisher's exact test, depending on the sample size.

RESULTS

There were 23 patients positive for one of the three founder BRCA mutations. Fourteen patients were positive for the 185delAG mutation, 2 patients were positive for the 5382insC mutation, and 7 patients were positive for the 6174 delT mutation (61, 9, and 30%, respectively). This represented a 25% incidence (95% CI: 16-34%) of one of the three founder BRCA mutations among our 92 Ashkenazi Jewish ovarian cancer patients. None of the patients was positive for more than one mutation. There was no statistically significant difference in parity, histology, grade, or stage between the BRCA founder mutation positive and negative patients. The difference between the percentage of mutation carriers among patients with one affected first-degree relative (13/22 or 59%) compared to those without at least one affected first-degree relative (10/70 or 14%) was highly significant (P = 0.001).

CONCLUSIONS

Ashkenazi Jewish ovarian cancer patients represent a group with a high likelihood of being carriers of BRCA 1 and 2 genetic mutations, regardless of family history. As a result, all ovarian cancer patients who are of Ashkenazi Jewish descent should be counseled regarding BRCA 1 and 2 genetic screening, as well as the potential implications of these results for the patient as well as her relatives in terms of prognosis, screening, chemoprevention, and consideration of prophylactic surgical procedures.

Endometrial histopathology in 700 patients treated with tamoxifen for breast cancer

OBJECTIVE

The aim of this study was the evaluation of endometrial histopathologic findings from 700 patients treated with tamoxifen (Tx) for breast cancer from two medical centers (United States and France).

METHODS

A retrospective review of data including histologic slides from 134 hysterectomies and 566 endometrial biopsies from Tx-treated patients who presented with abnormal vaginal bleeding and/or abnormal sonograms was performed. Analysis of histologic characteristics included inactive/atrophic and functional endometria, endometrial polyps, hyperplasia and metaplasia, and endometrial cancer. Duration of Tx therapy was recorded when available, and its correlation with endometrial pathology was assessed.

RESULTS

The only statistically significant difference between the data from the United States and France was the number of hysterectomies, which was almost double in France (27% vs 13.7%). Nonpathologic endometria made up 61.14% (inactive/atrophic 46%, functional 15.14%). Pathologic changes were found in 39.86% cases, of which polyps were 23.14%, glandular hyperplasia 8%, and metaplasia 3%; endometrial cancer made up 4.71% (33 cases). Nine cancers were well-differentiated endometrioid adenocarcinomas, and 24 were moderately or poorly differentiated, of which 13 had nonendometrioid components (serous, clear cell, MMMT). Fifteen cancers were found in endometrial polyps; 12 were invasive to the myometrium and 4 to blood vessels. The weight of the uteri exceeded 300 g in 15 cases, with 4 exceeding 900 g. The average age of all patients was 60.91 years and of the cancer patients alone it was 69.26 years. The shortest average duration of Tx therapy (2.5 years) was found in patients with inactive/atrophic endometria and the longest (6.8 years) in patients with endometrial cancer. Patients with endometrial polyps and cancer presented more often with abnormal vaginal bleeding than those with inactive/atrophic endometrium.

CONCLUSIONS

Most Tx-treated patients had no pathologic endometrial changes. Endometrial polyps, hyperplasia, and metaplasia, consistent with an estrogen-agonist effect of Tx, were found in roughly one-third of all patients. The endometrial cancers were often high-grade and invasive tumors. Patients with endometrial pathology were more often symptomatic than patients with inactive/atrophic endometria.

Nodulisporic acid opens insect glutamate-gated chloride channels: identification of a new high affinity modulator

Nodulisporic acid (NA) is an indole diterpene fungal product with insecticidal activity. NA activates a glutamate-gated chloride channel (GluCl) in grasshopper neurons and potentiates channel opening by glutamate. The endectocide ivermectin (IVM) induces a similar, but larger current than NA. Using Drosophila melanogaster head membranes, a high affinity binding site for NA was identified. Equilibrium binding studies show that an amide analogue, N-(2-hydroxyethyl-2,2-(3)H)nodulisporamide ([(3)H]NAmide), binds to a single population of sites in head membranes with a K(D) of 12 pM and a B(max) of 1.4 pmol/mg of protein. A similar K(D) is determined from the kinetics of ligand binding and dissociation. Four lines of evidence indicate that the binding site is a GluCl. First, NA potentiates opening of a glutamate-gated chloride current in grasshopper neurons. Second, glutamate inhibits the binding of [(3)H]NAmide by increasing the rate of dissociation 3-fold. Third, IVM potently inhibits the binding of [(3)H]NAmide and IVM binds to GluCls. Finally, the binding of [(3)H]IVM is inhibited by NA. The B(max) of [(3)H]IVM is twice that of [(3)H]NAmide, and about half of the [(3)H]IVM binding sites are inhibited by NA with high affinity (K(I) = 25 pM). In contrast, [(3)H]IVM binding to Caenorhabditis elegans membranes is not inhibited by NA at 100 nM, and there are no high affinity binding sites for NA on these membranes. Thus, half of the Drosophila IVM receptors and all of the NA receptors are associated with GluCl. NA distinguishes between nematode and insect GluCls and identifies subpopulations of IVM binding sites.

Evaluation of simplified protease inhibitor dosing regimens for the treatment of HIV infection

Complicated dosing regimens can unfavorably affect patient adherence and drug efficacy. In an effort to increase adherence while maximizing the benefits of the protease inhibitor (PI) component of HAART, the efficacy and safety of less frequent PI dosing regimens have recently been under scrutiny. Limiting the number of drugs required in antiretroviral therapy regimens may also minimize toxicity and drug-drug interactions. This article reviews the current movement toward twice-daily regimens and examines the efficacy and safety data available on twice-daily dosing of amprenavir, indinavir, nelfinavir, saquinavir soft-gel capsules, and ritonavir. Future trends in dosing are also discussed.

A randomized study of the safety and antiretroviral activity of hydroxyurea combined with didanosine in persons infected with human immunodeficiency virus type 1. American Foundation for AIDS Research Community-Based Clinical Trials Network

This randomized open-label trial of human immunodeficiency virus type 1-infected persons compared safety and efficacy for 38 patients receiving hydroxyurea/didanosine combination therapy with findings in 42 persons given didanosine monotherapy for 12 weeks, followed by 12 weeks of hydroxyurea/didanosine combination therapy for all patients. Week 12 on-treatment group comparisons showed a mean decrease in virus load between hydroxyurea/didanosine versus didanosine groups of -0.93 versus -0.74 log10 copies/mL (P=.20); a higher percentage of the hydroxyurea/didanosine group below the assay's detection limit (500 copies/mL), 29% versus 7% (P=.017); and median change in CD4 cells for the hydroxyurea/didanosine versus didanosine group of 0 versus 43 cells/mm3 (P=.045), although median change in CD4 percentage was similar (0.9% vs. 1.2%, P=.64). Week 24 virus load reductions and CD4 cell changes were similar in both groups. Intent-to-treat and on-treatment analyses showed similar results. The hydroxyurea/didanosine combination was well tolerated.

Simple sequence repeats in Escherichia coli: abundance, distribution, composition, and polymorphism

Computer-based genome-wide screening of the DNA sequence of Escherichia coli strain K12 revealed tens of thousands of tandem simple sequence repeat (SSR) tracts, with motifs ranging from 1 to 6 nucleotides. SSRs were well distributed throughout the genome. Mononucleotide SSRs were over-represented in noncoding regions and under-represented in open reading frames (ORFs). Nucleotide composition of mono- and dinucleotide SSRs, both in ORFs and in noncoding regions, differed from that of the genomic region in which they occurred, with 93% of all mononucleotide SSRs proving to be of A or T. Computer-based analysis of the fine position of every SSR locus in the noncoding portion of the genome relative to downstream ORFs showed SSRs located in areas that could affect gene regulation. DNA sequences at 14 arbitrarily chosen SSR tracts were compared among E. coli strains. Polymorphisms of SSR copy number were observed at four of seven mononucleotide SSR tracts screened, with all polymorphisms occurring in noncoding regions. SSR polymorphism could prove important as a genome-wide source of variation, both for practical applications (including rapid detection, strain identification, and detection of loci affecting key phenotypes) and for evolutionary adaptation of microbes.

Simple sequence repeats in Escherichia coli: abundance, distribution, composition, and polymorphism

Computer-based genome-wide screening of the DNA sequence of Escherichia coli strain K12 revealed tens of thousands of tandem simple sequence repeat (SSR) tracts, with motifs ranging from 1 to 6 nucleotides. SSRs were well distributed throughout the genome. Mononucleotide SSRs were over-represented in noncoding regions and under-represented in open reading frames (ORFs). Nucleotide composition of mono- and dinucleotide SSRs, both in ORFs and in noncoding regions, differed from that of the genomic region in which they occurred, with 93% of all mononucleotide SSRs proving to be of A or T. Computer-based analysis of the fine position of every SSR locus in the noncoding portion of the genome relative to downstream ORFs showed SSRs located in areas that could affect gene regulation. DNA sequences at 14 arbitrarily chosen SSR tracts were compared among E. coli strains. Polymorphisms of SSR copy number were observed at four of seven mononucleotide SSR tracts screened, with all polymorphisms occurring in noncoding regions. SSR polymorphism could prove important as a genome-wide source of variation, both for practical applications (including rapid detection, strain identification, and detection of loci affecting key phenotypes) and for evolutionary adaptation of microbes.

WIN 17317-3, a new high-affinity probe for voltage-gated sodium channels

The iminodihydroquinoline WIN 17317-3 was previously shown to inhibit selectively the voltage-gated potassium channels, K(v)1.3 and K(v)1.4 [Hill, R. J., et al. (1995) Mol. Pharmacol. 48, 98-104; Nguyen, A., et al. (1996) Mol. Pharmacol. 50, 1672-1679]. Since these channels are found in brain, radiolabeled WIN 17317-3 was synthesized to probe neuronal K(v)1 channels. In rat brain synaptic membranes, [(3)H]WIN 17317-3 binds reversibly and saturably to a single class of high-affinity sites (K(d) 2.2 +/- 0.3 nM; B(max) 5.4 +/- 0.2 pmol/mg of protein). However, the interaction of [(3)H]WIN 17317-3 with brain membranes is not sensitive to any of several well-characterized potassium channel ligands. Rather, binding is modulated by numerous structurally unrelated sodium channel effectors (e.g., channel toxins, local anesthetics, antiarrhythmics, and cardiotonics). The potency and rank order of effectiveness of these agents in affecting [(3)H]WIN 17317-3 binding is consistent with their known abilities to modify sodium channel activity. Autoradiograms of rat brain sections indicate that the distribution of [(3)H]WIN 17317-3 binding sites is in excellent agreement with that of sodium channels. Furthermore, WIN 17317-3 inhibits sodium currents in CHO cells stably transfected with the rat brain IIA sodium channel with high affinity (K(i) 9 nM), as well as agonist-stimulated (22)Na uptake in this cell line. WIN 17317-3 interacts similarly with skeletal muscle sodium channels but is a weaker inhibitor of the cardiac sodium channel. Together, these results demonstrate that WIN 17317-3 is a new, high-affinity, subtype-selective ligand for sodium channels and is a potent blocker of brain IIA sodium channels.

Laparoscopic lymphadenectomy for gynecologic malignancies

OBJECTIVE

The purpose of our study was to detail our 5-year experience with laparoscopic lymphadenectomy for gynecologic malignancies.

METHODS

From 11/5/92 to 3/9/98, we performed laparoscopic lymphadenectomies on 94 patients with various gynecologic malignancies. Pelvic, paraaortic, and combinations of both pelvic and paraaortic lymphadenectomies were performed depending on the primary site of disease and indication for lymph node dissection. Data were prospectively collected on all patients.

RESULTS

From 11/5/92 to 3/9/98 we performed 94 laparoscopic lymphadenectomies for gynecologic malignancies. The distribution included 64 patients with cervical cancer, 14 with ovarian cancer, 12 with endometrial cancer, 2 with fallopian tube cancer, 1 with a uterine malignant mixed mesodermal tumor, and 1 with a metastatic neuroendocrine tumor. Fifty-five patients had only pelvic lymph node dissections, 9 patients had paraaortic dissections only, and 30 had both pelvic and paraaortic dissections performed. Among 30 patients having laparoscopic lymphadenectomy only, the mean hospital stay was 3.6 days. Included in this group were 19 patients who received postoperative neoadjuvant chemotherapy for cervical cancer as inpatients prior to ambulatory radiation therapy. The mean length of stay for this group was 4.6 days versus 1.7 days for the 11 patients who did not receive postoperative chemotherapy (P = 0.0025). The mean number of pelvic nodes was 11.9 (range 0-57), with a mean of 4. 5 between 11/5/92 and 12/31/95 and a mean of 19.1 from 1/1/96 to 3/9/98. The mean number of paraaortic nodes obtained was 3.7 (range 0-14), with a mean of 3.4 from 11/5/92 to 12/31/95 and a mean of 4.1 from 1/1/96 to 3/9/98. A total of 3 patients required conversions to laparotomy. One was for a vascular injury to the vena cava, 1 for a large tumor extending to both sidewalls, and the third for removal of densely matted lymph nodes.

CONCLUSIONS

Laparoscopic lymphadenectomy is a technically feasible procedure for patients with gynecologic malignancies requiring lymph node dissections, with an acceptable safety profile and nodal yield. The number of nodes obtained increased in direct proportion to operator experience. In addition, patients may benefit from a decrease in hospital stay compared to conventional lymphadenectomy via laparotomy.

Laparoscopic management of adnexal masses in premenopausal and postmenopausal women

OBJECTIVE

To evaluate the feasibility and safety of laparoscopic adnexal mass removal in patients without preselection for benign pathology and assess the operative complications and findings.

METHODS

All patients presenting to the gynecologic oncology service between April 1992 and April 1996 with adnexal masses were candidates for laparoscopic management. Patients underwent preoperative radiological studies and office pelvic examination. Laparoscopic management was attempted on patients without evidence of gross metastatic disease or masses that extended above the umbilicus. Laparotomy was performed if indicated by pathologic findings or technical difficulty. All removed adnexal masses were sent for immediate pathologic diagnosis. The type of procedure, intraoperative findings, and complications were all recorded at the time of procedure.

RESULTS

One hundred sixty patients underwent laparoscopic evaluation for an adnexal mass. Benign pathology was discovered in 139 (87%, 95% confidence interval [CI] 84, 90) patients, and 141 (88%, 95% CI 86, 91) patients were managed laparoscopically. Reasons for laparotomy included technical difficulty, operative complications, or malignancy. Frozen section diagnosis was concordant with the final pathology reports in all but five patients (97% concordance), and no discrepancies resulted in treatment delays.

CONCLUSION

Laparoscopic management of adnexal masses can be successful in a gynecologic oncology population if there is expertise in operative laparoscopy, availability of immediate accurate pathologic examination, and appropriate further treatment where indicated.

Chemotherapy in advanced ovarian cancer: four systematic meta-analyses of individual patient data from 37 randomized trials. Advanced Ovarian Cancer Trialists' Group

The purpose of this systematic study was to provide an up to date and reliable quantitative summary of the relative benefits of various types of chemotherapy (non-platinum vs platinum, single-agent vs combination and carboplatin vs cisplatin) in the treatment of advanced ovarian cancer. Also, to investigate whether well-defined patient subgroups benefit more or less from cisplatin- or carboplatin-based therapy. Meta-analyses were based on updated individual patient data from all available randomized controlled trials (published and unpublished), including 37 trials, 5667 patients and 4664 deaths. The results suggest that platinum-based chemotherapy is better than non-platinum therapy, show a trend in favour of platinum combinations over single-agent platinum, and suggest that cisplatin and carboplatin are equally effective. There is no good evidence that cisplatin is more or less effective than carboplatin in any particular subgroup of patients.

Results of selective use of operative laparoscopy in gynecologic oncology

OBJECTIVE

To evaluate the impact of integration of operative laparoscopy on length of stay (LOS) and complication rates on an academic gynecologic oncology service.

METHODS

Retrospective analysis of all admissions to our gynecologic oncology service was performed for the academic years 1990/1991 and 1993/1994. Primary endpoints were frequency of complications and LOS.

RESULTS

In 1990/1991, there were 785 total admissions, of which 287 were surgical and 3% were approached laparoscopically. In 1993/1994, there were 973 admissions of which 436 were surgical and 23% were approached laparoscopically. Operative laparoscopy was applied equally regardless of age and reproductive status; the utilization of laparoscopy was increased by 14-fold for patients with cancer, 4. 5-fold for patients with benign disease, and 12-fold for patients with adnexal masses. No change in the mean LOS of nonsurgical admissions was noted, yet overall LOS for all patients decreased from 6.3 to 4.8 days (P < 0.0001). Mean LOS in surgical patients decreased from 9.4 to 6.0 days (P < 0.0001). After correction for complications, decreases in LOS only occurred in procedures for which laparoscopy was significantly integrated. No reductions in LOS were noted with like surgical approaches; i.e., there was no change in the LOS of patients undergoing laparotomy in both years. Surgical complications were not increased by laparoscopy.

CONCLUSIONS

Aggressive utilization of operative laparoscopy, even only for selected patients, into the surgical practice of a gynecologic oncology service demonstrates significant improvements in LOS without adversely affecting surgical complication rates.