Continuous ambulatory peritoneal dialysis (CAPD) versus hospital or home haemodialysis for end-stage renal disease in adults

BACKGROUND

Renal replacement therapy (RRT) with dialysis and transplantation is the only means of sustaining life for patients with end-stage renal disease (ESRD). Although transplantation is the treatment of choice, the number of donor kidneys are limited and transplants may fail. Hence many patients require long-term or even life-long dialysis. Continuous ambulatory peritoneal dialysis (CAPD) is an alternative to hospital or home haemodialysis for patients with ESRD.

OBJECTIVES

To assess the benefits and harms of CAPD versus hospital or home haemodialysis for adults with ESRD.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (Cochrane Library, Issue 2, 2002), the Cochrane Renal Group's Specialised Register (May 2002), MEDLINE (1966 - May 2002), EMBASE (1980 - May 2002), BIOSIS, CINHAL, SIGLE and NRR without language restriction. Reference lists of retrieved articles and conference proceedings were searched and known investigators and biomedical companies were contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing CAPD to hospital or home haemodialysis for adults with ESRD were to be included.

DATA COLLECTION AND ANALYSIS

Two reviewers were to independently assess the methodological quality of studies. Data was to be abstracted from included studies onto a standard form by one reviewer and checked by another. Statistical analyses were to be performed using the random effects model and the results to be expressed as relative risk (RR) with 95% confidence intervals (95% CI).

MAIN RESULTS

Despite extensive searching, no RCTs or quasi-RCTs were identified.

REVIEWER'S CONCLUSIONS

Data are not available to allow conclusions to be drawn about the relative effectiveness of CAPD compared with hospital or home haemodialysis for adults with ESRD. Efforts should be made to start and complete adequately powered RCTs, which compare the different dialysis modalities.

Utility of lymphangiography in the prediction of lymph node metastases in patients with cervical cancer

Our objective was to assess the value of lymphangiography in selecting patients for surgical staging of locally advanced cervical cancer. We reviewed our computerized database to identify patients with cervical cancer who had abnormal findings on lymphangiography and underwent retroperitoneal lymph node dissection between September 1991 and January 1996. The records of these patients were retrospectively reviewed, and the following data were retrieved: clinical tumor stage and findings on lymphangiography at surgery, and on pathologic examination of resected lymph nodes. The lymphangiograms were reviewed and reinterpreted in blinded fashion by two of the authors. The positive and negative predictive values of lymphangiography for the presence of lymph node metastases were calculated, with findings on pathologic examination of lymph nodes used as the gold standard. The positive and negative predictive values of surgeons' clinical assessments at surgery were also calculated. Fifty patients met the selection criteria and constituted the study population. Fourteen patients (28%) had histologically negative nodes, and 36 patients (72%) had lymph node metastases. Thirty-three patients had metastases to pelvic nodes, 1515 patients had metastases to common iliac nodes, and 1616 patients had metastases to para-aortic nodes. The positive predictive value of lymphangiography for lymph node metastases was 74% for pelvic nodes, 73% for common iliac nodes, and 88% for para-aortic nodes. The negative predictive value of lymphangiography for lymph node metastasis was 76% for common iliac nodes and 77% for para-aortic nodes. Overall, 46% of the patients selected for surgical exploration had histologic findings of either common iliac or para-aortic lymph node metastases; these findings led clinicians to extend radiation fields to cover the para-aortic lymph nodes. Lymphangiography is helpful in selecting patients with cervical cancer who have a high risk of common iliac or para-aortic lymph node metastasis. However, more accurate and more readily available noninvasive methods of evaluating cervical patients for the presence of regional disease continue to be needed.

Frequency of administration of recombinant human erythropoietin for anaemia of end-stage renal disease in dialysis patients

BACKGROUND

Although the benefits of recombinant human erythropoietin (rHu EPO) administration in dialysis patients have been demonstrated the optimal frequency regimen has not as yet been established. Treatment with rHu EPO is expensive, there is therefore a need for optimising the efficiency of its administration.

OBJECTIVES

The objectives of this review were to assess the effects of different frequency regimens of rHu EPO administration in dialysis patients in terms of i) effectiveness (correction of anaemia, quality of life and freedom from adverse events) ii) efficiency (optimal resource use) of different rHu EPO dose regimen policies.

SEARCH STRATEGY

We searched MEDLINE (1980 to May Week 3 2001), EMBASE (1984 to Week 24 2001), BIOSIS (1985 to January 1997), CINAHL (1982 to October 1997), The Cochrane Library (Issue 1, 1997), CHEMABS (1984 to November 1996), SIGLE (1980 to June 1996), CRIB (10th edition, 1995), UK NRR (14th consolidation, September 1996), RSC ( 1980 to February 1997), HealthSTAR (1995 to October 1997), IBSS (1984 to July 1997), NEED (July 1997) and reference lists of relevant articles. We contacted biomedical companies and investigators in the field and we hand searched Kidney International (including all supplements but excluding all conference proceedings except for 1994) July 1983 to May 1997 inclusive. The Internet was also searched on: August 1997. We had also identified some studies from a previous broad search for all randomised controlled trials (RCTs) relevant to the management of end-stage renal disease. Date of the most recent search: June 2001.

SELECTION CRITERIA

All randomised or quasi randomised controlled trials comparing different frequencies of rHu EPO administration in dialysis patients. Subgroup analyses were performed comparing haemodialysis and CAPD patients and also subcutaneous and intravenous administration.

DATA COLLECTION AND ANALYSIS

Only published data were used. Data were abstracted by a single investigator on to a standard form. The data abstracted were relevant to the predetermined outcome measures: measures of correction of anaemia, rHu EPO dose, quality of life measures, adverse events, number of withdrawals from study, mortality. Where appropriate, a summary relative risk (RR) was calculated for dichotomous data and a weighted mean difference (WMD) or standardised mean difference (SMD) for continuous data.

MAIN RESULTS

Eight studies met our inclusion criteria. When once a week administration was compared with twice weekly there was no significant difference in the ability to maintain the target haemoglobin (RR 1.00, 95% CI 0.42 to 2.40). Mean haemoglobin after twelve weeks of therapy was not different between the two groups (WMD -0.21g/dl, 95% CI -0.98 to 0.56). No difference was found in mean haemoglobin or haematocrit at the end of any studies which compared once with thrice weekly administration of rHu EPO (SMD -0.31, 95% CI -0.67 to 0.06). A single study which compared once with more that thrice weekly administration showed no significant difference in mean haemoglobin at the end of the maintenance phase (mean difference -0.2g/dl, 95% CI -0.65 to 0.25). The dosage of erythropoietin required by those on haemodialysis receiving rHu EPO once weekly was just significantly more (WMD 12.0 U/kg, 95% CI 0.24 to 23.76) than those receiving it twice weekly but the confidence interval is wide. No such difference was found for CAPD patients nor when the results were combined (WMD 5.15 U/kg, 95% CI -3.74 to 14.05). The result was not significant when comparing once weekly with thrice weekly administration (WMD 10.00 U/kg, 95% CI -80.87 to 100.87). There was no difference in the frequency of adverse events between any of the groups studies.

REVIEWER'S CONCLUSIONS

There is no significant difference between once weekly versus thrice weekly subcutaneous administration of rHu EPO. Once weekly administration of rHu EPO would require an additional 12U/kg/week for patients on haemodialysis, however this is based on one very small study. The cost of this additional hRu EPO nee, however this is based on one very small study. The cost of this additional hRu EPO needs to assessed, in particular with regard to patient preference and compliance.

Utility of lymphangiography in the prediction of lymph node metastases in patients with cervical cancer

Our objective was to assess the value of lymphangiography in selecting patients for surgical staging of locally advanced cervical cancer. We reviewed our computerized database to identify patients with cervical cancer who had abnormal findings on lymphangiography and underwent retroperitoneal lymph node dissection between September 1991 and January 1996. The records of these patients were retrospectively reviewed, and the following data were retrieved: clinical tumor stage and findings on lymphangiography at surgery, and on pathologic examination of resected lymph nodes. The lymphangiograms were reviewed and reinterpreted in blinded fashion by two of the authors. The positive and negative predictive values of lymphangiography for the presence of lymph node metastases were calculated, with findings on pathologic examination of lymph nodes used as the gold standard. The positive and negative predictive values of surgeons' clinical assessments at surgery were also calculated. Fifty patients met the selection criteria and constituted the study population. Fourteen patients (28%) had histologically negative nodes, and 36 patients (72%) had lymph node metastases. Thirty-three patients had metastases to pelvic nodes, 1515 patients had metastases to common iliac nodes, and 1616 patients had metastases to para-aortic nodes. The positive predictive value of lymphangiography for lymph node metastases was 74% for pelvic nodes, 73% for common iliac nodes, and 88% for para-aortic nodes. The negative predictive value of lymphangiography for lymph node metastasis was 76% for common iliac nodes and 77% for para-aortic nodes. Overall, 46% of the patients selected for surgical exploration had histologic findings of either common iliac or para-aortic lymph node metastases; these findings led clinicians to extend radiation fields to cover the para-aortic lymph nodes. Lymphangiography is helpful in selecting patients with cervical cancer who have a high risk of common iliac or para-aortic lymph node metastasis. However, more accurate and more readily available noninvasive methods of evaluating cervical patients for the presence of regional disease continue to be needed.

Paracrine interactions of chondrocytes and macrophages in cartilage degradation: articular chondrocytes provide factors that activate macrophage-derived pro-gelatinase B (pro-MMP-9)

Cells of the monocyte/macrophage lineage are involved in the development of inflammatory joint diseases such as rheumatoid arthritis. This disease is characterized by cartilage degradation and synovial membrane inflammation with a progressive loss of joint function. The pathological processes are still not well understood. Therefore it would be interesting to develop a suitable experimental in vitro model system for defined studies of monocyte/macrophage and chondrocyte interactions at the molecular level. For that purpose we cocultured chondrocytes from adult human articular cartilage with human monocytes and macrophages for defined periods of time in agarose without addition of serum. We performed zymographic and western blot analysis of culture medium, completed by quantitative RT-PCR of each chondrocyte, monocyte and macrophage RNA, respectively. The reliability of the newly established coculture systems is confirmed by causing a clear decrease of intact aggrecan in the coculture medium plus concurrent appearance of additional smaller fragments and a reduction of chondrocyte aggrecan and collagen II gene expression in the presence of monocytes. In culture medium from cocultures we detected active forms of the matrix metalloproteinases MMP-1, MMP-3 and MMP-9 accompanied by induction of gene expression of MMP-1, membrane type 1 MMP (MT1-MMP) and tissue inhibitor of metalloproteinase 2 (TIMP-2) in chondrocytes. No gene expression of MMP-9 was detectable in chondrocytes, the enzyme was solely expressed in monocytes and macrophages and was downregulated in the presence of chondrocytes. Our results suggest that MMP-9 protein in coculture medium originated from monocytes and macrophages but activation required chondrocyte-derived factors. Because addition of plasmin, a partial activator of pro-MMP-3 and pro-MMP-1, enhanced the activation of pro-MMP-9 and pro-MMP-1 in cocultures but not in monocultured macrophages, and the presence of MMP-3 inhibitor II prevented pro-MMP-9 activation, we assumed a stepwise activation process of pro-MMP-9 that is dependent on the presence of at least MMP-3 and possibly also MMP-1.

Conjugation with (111)In-DTPA-poly(ethylene glycol) improves imaging of anti-EGF receptor antibody C225

Significant liver uptake often limits the clinical application of radiolabeled antibodies in radioimmunodetection. The purpose of this study was to evaluate the gamma-imaging properties of an antiepidermal growth factor receptor (EGFR) antibody, C225, conjugated with heterofunctional poly(ethylene glycol) (PEG) with 1 terminus of the polymer attached to a radiometal chelator, diethylenetriaminepentaacetic acid (DTPA).

METHODS

Two preparations of PEG-modified C225, one with 20% and the other with 60% amine substitution, were labeled with (111)In. The conjugates, (111)In-DTPA-PEG-C225, were injected intravenously into nude mice with EGFR-positive A431 tumors. For comparison, C225 directly labeled with (111)In was also injected. In a competitive study, mice with A431 tumors were pretreated intravenously with 100-fold excess of native C225, followed by an injection of (111)In-DTPA-PEG-C225 30 min or 20 h later. In addition, (111)In-DTPA-PEG-C225 was injected into mice with EGFR-positive MDA-MB-468 tumors and EGFR-negative MDA-MB-435 tumors. Images were acquired at 5 min and at 2, 6, 24, and 48 h after injection of the radiotracers. Regions of interest (ROIs) were drawn on the computer images around the whole body, liver, muscle, and tumor. The counts per pixel in the tumor and normal tissues were calculated. At 48 h, the mice were killed and dissected. Blood, liver, muscle, and tumor samples were removed and the radioactivity of each sample was measured.

RESULTS

In A431 tumor xenografts, the tumor uptake of C225 modified with PEG was not significantly different than the uptake of unmodified (111)In-DTPA-C225. Uptake in the liver, however, was reduced by 38%-45%, and the reduction increased with increasing degree of PEG substitution. Tumors of A431 and MDA-MB-468 xenografts were clearly visualized with (111)In-DTPA-PEG-C225, whereas tumors of the MDA-MB-435 xenograft, which expresses low levels of EGFR, were not as readily visible. The tumor-to-blood ratios of (111)In-DTPA-PEG-C225 in A431 and MDA-MB-468 xenografts were about 3 fold higher than in MDA-MB-435 xenografts. Blocking EGFR by pretreatment with native C225 significantly reduced the uptake of (111)In-DTPA-PEG-C225 in the liver. The tumor-to-blood ratios in mice with A431 tumors were decreased 2.5-2.7 fold after pretreatment with a large excess of C225. Similar results were obtained with MDA-MB-468 tumor xenografts. In contrast, the tumor-to-blood ratios in mice with MDA-MB-435 tumor xenografts were not significantly different in C225-pretreated mice than in nonpretreated mice.

CONCLUSION

These findings indicate that (111)In-DTPA-PEG-C225 selectively localized to the tumors expressing high levels of EGFR. PEG-modification of C225 significantly reduced its liver uptake, resulting in improved visualization of EGFR-positive tumors. Using PEG as a linker between the monoclonal antibody and metal chelator is a useful strategy to optimize the imaging characteristics of antibody-based scintigraphic agents.

Vascular dysfunction after repair of coarctation of the aorta: impact of early surgery

BACKGROUND

Patients with repaired coarctation are at increased risk of hypertension and cardiovascular disease despite successful repair. We studied the function of conduit arteries in upper and lower limbs of patients late after successful coarctation repair and its relation to age at surgery.

METHODS AND RESULTS

Flow-mediated dilatation (FMD) and the dilatation after sublingual nitroglycerin (NTG, 25 microgram) were measured by using high-resolution ultrasound in the brachial artery in 64 coarctation patients (44 males and 20 females, aged 19+/-10 years; median age at operation 4 months) and 45 control subjects (28 males and 17 females, aged 19+/-10 years) and in the posterior tibial artery in 37 patients and 22 control subjects. Arterial stiffness was determined by pulse-wave velocity (PWV) of the brachioradial and femoral-dorsalis pedis tracts. Patients, compared with control subjects, had lower brachial FMD (7.16+/-3.4% versus 8.62+/-2.3%, respectively; P=0.02) and NTG (11.46+/-4.3% versus 13.21+/-4.6%, respectively; P=0.046) and higher brachioradial PWV (9.17+/-3.1 versus 8.06+/-1.9 m/s, respectively; P=0.05). In contrast, posterior tibial FMD, NTG, and lower limb PWV were comparable. Age (months) at the time of repair was related to brachioradial PWV (r=0.42, P=0.002) but not to brachial FMD or NTG.

CONCLUSIONS

Patients with repaired aortic coarctation have impaired conduit artery function, with abnormal responses to flow and NTG, and increased vascular stiffness confined to the upper part of the body. Early repair is associated with preserved elastic properties of conduit arteries, but reduced reactivity remains.

Imaging techniques used for the detection of 8-oxoguanine adducts and DNA repair proteins in cells and tissues

The presence of 8-oxoguanine (8-oxoG) in DNA is considered a marker of oxidative stress and DNA damage. Numerous biochemical techniques have been described for its detection in cells or tissues. Although these approaches are quantitative, they do not provide insights into whether the lesion occurs in mitochrondrial versus genomic DNA. In addition, biochemical techniques are not amenable to the evaluation of individual cells or archival tissues. Antibodies have been raised against 8-oxoG, which may circumvent some of these issues. In this review, we described the use of in situ imaging techniques to detect oxidative DNA damage including the comet assay. We will review our previous work that describes the utility of an antibody fragment (Fab) engineered to recognize 8-oxoG in DNA. Furthermore, we will discuss the analysis of DNA repair enzymes in the assessment of oxidative DNA damage. Finally, advantages and potential concerns associated with immunodetection of 8-oxoG are discussed.

Postadmission disparities in nursing home stays of whites and minority elderly

This study examined the type of nursing home stay of white and minority elderly and investigated whether minority differences in nursing home admissions were extended to the type of stay, and if so, what accounted for those differences. African American/white and Latino/white elderly were compared with respect to stays of (1) longer than three months, (2) shorter than three months and discharged alive (recovery), and (3) shorter than three months and deceased (terminal). African American elderly in nursing homes were significantly less likely to have recovery stays than were white elderly. Multivariate analysis revealed that this difference was due to Medicaid coverage. Overall, elderly with Medicaid coverage were more likely to make long-term stays in nursing homes. The findings highlight the importance of Medicaid coverage for short-term recovery nursing home stays. Reductions of benefits or restrictions in eligibility would negatively and disproportionately affect the nursing home stays of elderly African Americans.

Potentiation of radioresponse by polymer-drug conjugates

Although combined chemotherapy and radiotherapy has produced significantly improved response and survival rates among cancer patients, there is still a compelling need to establish the most effective way to deliver these agents. We hypothesize that the radiosensitizing effect of a chemotherapeutic agent can be further enhanced if the drug is delivered at an optimal concentration and is maintained in the tumor for a prolonged period. Using a water-soluble poly(L-glutamic acid)-conjugated paclitaxel (PG-TXL) as a model compound, we investigated whether paclitaxel delivered by means of polymeric carrier could increase the tumor's response to radiation. Mice bearing 8-mm syngeneic ovarian carcinoma OCa-1 tumors implanted intramuscularly were treated with i.v. injected PG-TXL alone or in combination with single doses of local radiation. The enhancement factors at 24 h interval, as measured by incremental tumor growth delay compared with radiation alone, ranged from 2.48 to 4.28. The values varied as a function of radiation dose. The enhancement of radioresponse is also a function of time interval between injection of PG-TXL and tumor irradiation. The enhancement factor increased with decreasing interval, suggesting that radiation may in turn mediate the sensitivity of tumor toward PG-TXL. Thus, the mechanism of PG-TXL's radiopotentiation activity is probably multifactorial. Remarkably, while combined radiation and TXL produced additive or even sub-additive interaction when radiation preceded TXL injection, combined radiation and PG-TXL produced synergistic interaction in a mammary MCa-4 tumor model. Radiation significantly increased tumor uptake of PG-TXL, suggesting a potential role of radiation-modulated antitumor activity of polymeric drugs. Our data support a treatment strategy combining radiation and polymeric chemotherapy that may have important clinical implications in terms of scheduling and optimization of the therapeutic ratio.

Poly(ethylene glycol)-conjugated anti-EGF receptor antibody C225 with radiometal chelator attached to the termini of polymer chains

Several biological barriers, including significant liver uptake, limit the clinical application of radiolabeled antibodies in radioimmunoscintigraphy. Here, a general approach is described for radiolabeling of monoclonal antibodies conjugated with poly(ethylene glycol) (PEG). This strategy is demonstrated with C225, a monoclonal antibody directed against epidermal growth factor (EGF) receptor. We synthesized a heterofunctional PEG with one end attached to a radiometal chelator, diethylenetriaminepentaacetic acid (DTPA), and the other end to a protected thiol group, S-acetylthioacetate. After a deprotection step, the resulting DTPA-PEG-SH was conjugated to maleimide-activated C225 to yield DTPA-PEG-C225 conjugate. Characterization of DTPA-PEG-C225 with immunoprecipitation and Western blot analysis revealed that the conjugate was biologically active in binding to the EGF receptor in A431 cells. Competitive EGF receptor binding assay in MDA-MB-468 cells showed that DTPA-PEG-C225, with up to 60% of the amino groups in C225 substituted, retained 66% of C225's binding affinity. Moreover, DTPA-PEG-C225 with increasing degrees of NH(2) substitution from 20% to 70% retained the activity of C225 to induce apoptosis in DiFi cells. More importantly, DTPA-PEG-C225 demonstrated less nonspecific interaction than DTPA-C225. Pharmacokinetic analysis using (111)In-labeled compounds revealed narrower steady-state distribution of (111)In-DTPA-PEG-C225 than (111)In-DTPA-C225, probably due to reduced nonspecific binding of PEG-modified antibody to tissues. The terminal half-life (t(1/2,)(gamma)) of (111)In-DTPA-PEG-C225, 21.1 h, was shorter than that of (111)In-DTPA-C225, 52.9 h. These data suggest that (111)In-DTPA-PEG-C225 may provide better imaging characteristics than (111)In-DTPA-C225, and that using PEG as a linker between the monoclonal antibody and DTPA may be a promising strategy in optimizing the imaging characteristics of immunoscintigraphic agents.

Alternative solutions to the problem of selection bias in an analysis of federal residential drug treatment programs

In an evaluation of prison-based residential drug treatment programs, the authors use three different regression-based approaches to estimating treatment effects. Two of the approaches, the instrumental variable and the Heckman approach, attempt to minimize selection bias as an explanation for treatment outcomes. Estimates from these approaches are compared with estimates from a regression in which treatment is represented by a dummy variable. The article discusses the advantage of using more than one method to increase confidence in findings when possible selection bias is a concern. Three-year outcome data for 2,315 federal inmates are used in analyses where the authors separately examine criminal recidivism and relapse to drug use for men and women. Statistical tests lead the authors to conclude that treatment reduces criminal recidivism and relapse to drug use. The treatment effect was largest when the inference was based on the Heckman approach, somewhat smaller when based on the instrumental variable approach, and smallest when based on the traditional dummy variable approach. Treatment effects for females were not statistically significant.

Federal prison residential drug treatment reduces substance use and arrests after release

OBJECTIVE

The effectiveness of federal prison-based residential drug and alcohol treatment programs was evaluated using event history procedures that addressed the problem of selection bias and included a wide range of control variables.

METHODS

The sample comprised 760 treatment subjects and 809 comparison subjects. Treatment subjects were from 20 different prisons of medium, low, and minimum security levels. Comparison subjects were drawn from over 30 prisons.

RESULTS

The results indicated that individuals who entered and completed in-prison residential treatment were less likely to experience the critical postrelease outcomes of new arrests and substance use during the first 6 months following release.

CONCLUSIONS

Without controlling for selection bias, the effects of treatment would most likely have been attenuated. The results have greater generalizability than other studies of prison-based treatment. This study occurred within a multisite context of 20 programs serving both male and female inmates and operating within different security levels and different geographic regions.

Dosimetry errors in endovascular high-dose-rate brachytherapy

Monte Carlo data were used to demonstrate the dosimetry of the microSelectron high-dose-rate (HDR) iridium 192 (192Ir) stepping source. These data were used to assess the accuracy of the Nucletron brachytherapy planning system (BPS version 13) for peripheral vessel endovascular brachytherapy. Dose rates from the high-dose-rate (HDR) source are calculated using the Monte Carlo code MCNP4A. Calculations are made at 0.25-cm intervals in the longitudinal direction on sleeves of radii of 1 and 0.25 cm. The Monte Carlo data are summed and weighted to simulate the longitudinal dose distribution at a distance of 1 and 0.25 cm from an 192Ir source stepping through a straight pathway. A comparison is made between the simulated Monte Carlo dosimetry and the Nucletron brachytherapy planning system's dosimetry. This study illustrates and quantifies the dosimetric errors at small distances associated with a point source dose calculation algorithm. The effects of step size, dwell time optimization, and active length on the accuracy of BPS v.13 for HDR endovascular brachytherapy are demonstrated.

Genome scan of idiopathic generalized epilepsy: evidence for major susceptibility gene and modifying genes influencing the seizure type

Idiopathic generalized epilepsy (IGE) is a common, complex disease with an almost exclusively genetic etiology but with variable phenotypes. Clinically, IGE can be divided into different syndromes. Varying lines of evidence point to the involvement of several interacting genes in the etiology of IGE. We performed a genome scan in 91 families ascertained through a proband with adolescent-onset IGE. The IGEs included juvenile myoclonic epilepsy (JME), juvenile absence epilepsy (JAE), and epilepsy with generalized tonic clonic seizures (EGTCS). Our linkage results support an oligogenic model for IGE, with strong evidence for a locus common to most IGEs on chromosome 18 (lod score 4.4/5.2 multipoint/two-point) and other loci that may influence specific seizure phenotypes for different IGEs: a previously identified locus on chromosome 6 for JME (lod score 2.5/4.2), a locus on chromosome 8 influencing non-JME forms of IGE (lod score 3.8/2.5), and, more tentatively, two newly discovered loci for absence seizures on chromosome 5 (lod scores 3.8/2.8 and 3.4/1.9). Our data also suggest that the genetic classification of different forms of IGE is likely to cut across the clinical classification of these subforms of IGE. We hypothesize that interactions of different combinations of these loci produce the related heterogeneous phenotypes seen in IGE families.

Biodistribution of paclitaxel and poly(L-glutamic acid)-paclitaxel conjugate in mice with ovarian OCa-1 tumor

PURPOSE

Poly(L-glutamic acid)-paclitaxel (PG-TXL) is a water-soluble paclitaxel (TXL) conjugate made by conjugating TXL to poly(L-glutamic acid) via ester bonds. In preclinical studies, PG-TXL has shown significant antitumor activity against a variety of solid tumors. To elucidate the relationship between tissue distribution and antitumor efficacy of PG-TXL, we studied and compared the biodistribution of PG-TXL and TXL.

METHODS

Female C3Hf/Kam mice bearing syngeneic ovarian OCa-1 tumors were injected with either [3H]TXL or PG-[3H]TXL at an equivalent TXL dose of 20 mg/kg. Mice were killed at various times after drug injection, and samples of blood, spleen, liver, kidney, lung, heart, muscle, brain, fat, and tumor were removed and the radioactivity counted. In addition, concentrations of free [3H]TXL released from PG-[3H]TXL in the spleen, liver, kidney, and tumor were analyzed by using high-performance liquid chromatography (HPLC). Whole-body autoradiographs of mice killed 1 day and 6 days after administration of PG-[3H]TXL were obtained to study the intratumoral distribution of PG-TXL.

RESULTS

When [3H]TXL was conjugated to polymer, the biodistribution pattern of PG-[3H]TXL differed from that of [3H]TXL. Based on area under the tissue concentration-time curve (AUC) values, tumor exposure to [3H]TXL was five times greater when administered as PG-TXL than as TXL formulated in Cremophor EL/alcohol vehicle. Furthermore, concentrations of free paclitaxel released from PG-[3H]TXL remained relatively constant in tumor tissue, being 489, 949 and 552 ng/g tumor tissue at 5, 48 and 144 h after dosing, respectively. Autoradiographic images of mice injected with PG-[3H]TXL revealed that radioactivity was primarily located in the periphery of the tumor on day 1 after drug administration and was homogeneously diffused into the center of the tumor by day 6. Over the 144-h study period, [3H]TXL concentrations, predominantly as the inactive conjugate, were higher in tissues with a more abundant reticular endothelial system (i.e. liver, kidney, spleen, lung) than in tissues with less abundant or lacking RE systems (i.e. muscle, fat, brain). Both [3H]TXL and PG-[3H]TXL were excreted primarily through the hepatobiliary route, with a small fraction of each drug (5% and 8.7%, respectively) excreted into the urine within 48 h.

CONCLUSIONS

This study indicates that the distribution to tumor tissue was enhanced when [3H]TXL was administered as a macromolecular conjugate, and that free TXL was released and maintained within the tumor for a prolonged period. Thus, the antitumor activity of PG-TXL observed in preclinical studies may be attributed in part to enhanced tumor uptake of PG-TXL.

Conjugation of camptothecins to poly-(L-glutamic acid)

Conjugation of water-insoluble cancer chemotherapeutic drugs to macromolecular polymers can lead to improved pharmaceutical properties and improved therapeutic ratios due to accumulation of the polymer-drug conjugate in tumor tissue through the enhanced permeability and retention (EPR) to macromolecules associated with tumor vasculature. Pharmaceutical shortcomings of certain active camptothecins including difficulty in formulation and instability of the active lactone form due to interactions with human albumin might be improved by conjugation to polymers. In this report, conjugations of camptothecin (CPT), 10-hydroxy-CPT, and 9-amino-CPT to poly-(L-glutamic acid) (PG) are described; coupling was accomplished either through the 20(S)-hydroxyl or 9 and 10 substituents with and without the use of a glycine linker. Studies using a PG paclitaxel conjugate (PG-TXL), which is currently in Phase I testing, demonstrated that PG enhanced aqueous solubility, prolonged plasma residence time, and greatly increased the distribution of paclitaxel to tumor tissue in a murine model. In this report, we describe the use of similar conjugation technology for CPT derivatives and demonstrate that these difficult to formulate compounds can be rendered water soluble, that their maximum tolerated doses are increased, and that they retain substantial anti-tumor activity in syngeneic and xenogeneic tumor models. Preliminary data suggest that PG with molecular weights between 37 and 50 kDa with CPT loading between 14% and 37% with or without glycine linkers display enhanced efficacy compared with nonconjugated camptothecins administered at their maximum tolerated dose.

Effectiveness of water soluble poly(L-glutamic acid)-camptothecin conjugate against resistant human lung cancer xenografted in nude mice

A camptothecin (CPT) formulation that can be easily administered, is less toxic, and has greater antitumor effect is needed. In this study, a water-soluble CPT derivative was obtained by direct coupling of CPT to poly(L-glutamic acid) (PG) through the C20(S)-hydroxyl group. CPT was released from the resulting conjugate, PG-CPT, in phosphate-buffered saline with a zero-order kinetics in the initial 50 days. The release rates were 0.623% per day, 1.081% per day, and 1.396% per day at pH 5.3, 7.4, and 9.0, respectively. In vitro, PG-CPT was less potent in inhibiting cell growth than was free CPT in all human tumor cell lines tested. However, PG-CPT showed better antitumor activity and tolerability than did CPT in vivo. When H322 human lung tumor cells were inoculated subcutaneously in nude mice, PG-CPT delayed the growth of these well-established tumors with an absolute growth delay of 32 days when given as 4 doses with 4-day intervals between injections at an equivalent CPT dose of 40 mg/kg. When H322 cells were inoculated intratracheally in nude mice, 5 doses of intravenous injection of PG-CPT at an equivalent CPT dose of 10 mg/kg on days 4, 8, 12, 16, and 20 after inoculation significantly prolonged the median survival of treated mice, averaging 1.8-fold that of untreated mice (p=0.01). Increasing the dose of PG-CPT to an equivalent CPT dose of 40 mg/kg per injection administered in 4 doses on days 4, 8, 12, and 16 prolonged the median survival of treated mice by 4-fold (p=0.0008). Significantly, mice with intratracheally inoculated H322 tumors were resistant to both CPT and cisplatin treatments. These studies demonstrated that PG may be used as an effective solubilizing carrier for CPT and that PG-CPT may have potential application in the treatment of lung cancer.

Gliomatosis cerebri in a 10-year-old girl masquerading as diffuse encephalomyelitis and spinal cord tumour

Gliomatosis cerebri is the unifying term used when diffuse glial infiltration occurs throughout the cerebral hemispheres. The very few cases reported in children have presented with intractable epilepsy, corticospinal tract deficits, unilateral tremor, headaches, and developmental delay. Antemortem diagnosis is difficult because of the vagueness of the physical, radiological and pathological findings. Adult cases may simulate an acute diffuse encephalomyelitis and show postmortem evidence of a marked swelling of the spinal cord. Apparently benign intracranial hypertension with papilloedema has also been recorded. We report a 10-year-old girl who presented with a history and physical signs suggestive of benign intracranial hypertension. A diffuse encephalomyelopathy occurred, which was complicated by spinal cord swelling, followed by deterioration and death. Gliomatosis cerebri affecting the brain and spinal cord was found at postmortem examination.

B-lymphotropic viruses in a novel tropical splenic lymphoma

Peripheral blood from patients with a novel tropical splenic lymphoma, characterized by splenomegaly and circulating naïve CD5-negative villous B lymphocytes, has been screened for evidence of an association with the B-lymphotropic viruses, Epstein--Barr virus (EBV), hepatitis C virus (HCV) and human herpesvirus 8 (HHV8). No increased prevalence of EBV, HCV and HHV8 was demonstrated using serological and molecular techniques, compared with a geographical, age-matched control group. However, lymphoma patients had markedly raised EBV antibody levels without a concomitant increase in the rate of detection of viral genomes in the peripheral blood. This phenomenon also occurred in patients with hyper-reactive malarial splenomegaly, a condition that occurs in the same geographical area and that is clinically indistinguishable from tropical splenic lymphoma, adding further weight to the suggestion that there may be an aetiological association between these two disorders.

Comparison of cellulose, modified cellulose and synthetic membranes in the haemodialysis of patients with end-stage renal disease

BACKGROUND

When the kidney fails the blood borne metabolites of protein breakdown and water cannot be excreted. The principle of haemodialysis is that such substances can be removed when blood is passed over a semipermeable membrane. Natural membrane materials can be used including cellulose or modified cellulose, more recently various synthetic membranes have been developed. Synthetic membranes are regarded as being more "biocompatible" in that they incite less of an immune response than cellulose-based membranes.

OBJECTIVES

To assess the effects of different haemodialysis membrane material in patients with end-stage renal disease (ESRD).

SEARCH STRATEGY

We searched Medline (1966 to December 2000), Embase (1981 to November 2000), PreMedline (29 November 2000), HealthStar (1975 to December 2000), Cinahl (1982 to October 2000), The Cochrane Controlled Trials Register (Issue 1, 1996), Biosis (1989 to June 1995), Sigle (1980 to June 1996), Crib (10th edition, 1995), UK National Research Register (September 1996), and reference lists of relevant articles. We contacted biomedical companies, investigators and we hand searched Kidney International (1980 to 1997). Date of the most recent searches: November 2000.

SELECTION CRITERIA

All randomised or quasi-randomised clinical trials comparing different haemodialysis membrane material in patients with ESRD.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the methodological quality of studies. Data was abstracted from included studies onto a standard form by one reviewer and checked by another.

MAIN RESULTS

Twenty seven studies met our inclusion criteria and where possible data from these were summated by meta-analyses (Peto's odds ratio (OR) and weighted mean difference (WMD) with 95% confidence intervals (CI)). Twenty two outcome measures were sought in 10 broad areas. For two (number of episodes of significant infection per year and quality of life) no data were available. For the comparison of cellulose with synthetic membranes, data for 12/20 outcome measures were available in only a single trial. For modified cellulose and synthetic membranes, data for three outcome measures were available in one trial only and for 12 of the outcomes no data were found, crossover studies were analysed separately and studies which randomised by patient yet analysed by dialysis sessions adjusted for clustering. Pre-dialysis beta2 microglobulin concentrations were significantly lower at the end of the studies in patients treated with synthetic membranes (WMD - 14.5; 95% CI -17.4 to -11.6). One crossover study showed a lowering of beta2 microglobulin when low flux synthetic membranes were used. When analysed for a change in beta2 microglobulin across a trial a fall was only noted when high flux membranes were used. In one very small study the incidence of amyloid was less in patients who were dialysed for six years with high flux synthetic membranes (OR 0.05; 95% CI 0.01 to 0.18). In the single study which measured triglyceride values there was a significant difference in favour of the synthetic (high flux) membrane (WMD -0.66; 95% CI -1.18 to -0.14). Serum albumin was higher in patients treated with synthetic membranes (both low and high flux) although this just bordered statistical significance (WMD -0.09; 95% CI -0.18 to 0.00). Dialysis adequacy measured by Kt/V was marginally higher when cellulose membranes were used (WMD 0.10; 95% CI 0.04 to 0.16). There was no significant difference between these membranes for any of the other clinical outcomes measures but confidence intervals were generally wide. No differences were found between modified cellulose and synthetic membranes although many fewer trials were carried out for this comparison.

REVIEWER'S CONCLUSIONS

For clinical practice This systematic literature review has generated no evidence of benefit when synthetic membranes were used compared with cellulose/modified cellulose membranes in terms of reduced mortality nor reduction in dialysis related adverse symptoms. Despite the relatively large number of RCTs undertaken in this area none of the included studies reported any measures of quality of life. End-of-study beta2 microglobulin values, and possibly the development of amyloid disease, were less in patients treated with synthetic membranes compared with cellulose membranes. Plasma triglyceride values were also lower with synthetic membranes in the single study that measured this outcome. Differences in these outcomes may have reflected the high flux of the synthetic membrane. Serum albumin was higher when synthetic membranes of both high and low flux were used. Kt/V and urea reduction ratio were higher when cellulose or modified cellulose membranes were used in the few studies that measured these outcomes. We are hesitant to recommend the universal use of synthetic membranes for haemodialysis in patients with ESRD because of; the small number of trials (particularly for modified cellulose membranes, most with low patient numbers), the heterogeneity of many of the trials compared, the variations in membrane flux, the differences in exclusion criteria, particularly relating to comorbidity and the relative lack of patient-centred outcomes studied. Such evidence as we have favours synthetic membranes but even if we assume extra benefit it may be at considerable cost, particularly if high flux synthetic membranes were to be used. For further research A further systematic review of RCTs comparing high and low flux haemodialysis membranes, subgrouped according to membrane composition (cellulose, modified cellulose, synthetic) and reporting clinical outcomes of major importance to patients needs to be undertaken. Further pragmatic RCTs are required to compare the different dialysis membranes available. We recommend that they: - Take into account other properties including flux as well as the material from which the membrane is made and test modified cellulose membranes as well as standard ones. - Record an agreed minimum dataset on primary outcomes of major importance to patients. - Explicitly record whether symptoms are patient- or staff-reported recognising that generally patient reporting will be more appropriate for evaluating effectiveness but staff reported data may be necessary for calculating the cost of treating complications. - Be multi-centre (and possibly multinational) to have sufficient patients to complete the study to allow for a considerable number of withdrawals and dropouts. - Have sufficient length of follow up to draw conclusions for important clinical outcome measures and continue to follow patients who have renal transplants. - Include older patients and those with comorbid illnesses and take into account age and comorbidity when assessing outcomes (possibly by stratification at trial entry). - Carry out, in parallel, an economic evaluation of the different policies being compared in the trial.

Double bag or Y-set versus standard transfer systems for continuous ambulatory peritoneal dialysis in end-stage renal disease

BACKGROUND

Peritonitis is the most frequent serious complication of continuous ambulatory peritoneal dialysis (CAPD). It has a major influence on the number of patients switching from CAPD to haemodialysis and has probably restricted the wider acceptance and uptake of CAPD as an alternative mode of dialysis.

OBJECTIVES

This systematic review sought to determine if modifications of the transfer set (Y-set or double bag systems) used in CAPD exchanges are associated with a reduction in peritonitis and an improvement in other relevant outcomes.

SEARCH STRATEGY

A broad search strategy was employed which attempted to identify all RCTs or quasi-RCTs relevant to the management of end-stage renal disease (ESRD). Five electronic databases were searched (Medline 1966-1999, EMBASE 1984-1999, CINAHL 1982-1996, BIOSIS 1985-1996 and the Cochrane Library), authors of included studies and relevant biomedical companies were contacted, reference lists of identified RCTs and relevant narrative reviews were screened and Kidney International 1980-1997 was hand searched.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing double bag, Y-set and standard CAPD exchange systems in patients with ESRD.

DATA COLLECTION AND ANALYSIS

Data were abstracted by a single investigator onto a standard form and subsequently entered into Review Manager 4.0.4. Odds Ratio (OR) for dichotomous data and a (Weighted) Mean Difference (WMD) for continuous data were calculated with 95% confidence intervals (95% CI).

MAIN RESULTS

Twelve eligible trials with a total of 991 randomised patients were identified. In trials comparing either the Y-set or double bag systems with the standard systems significantly fewer patients (OR 0.33, 95% CI 0.24 to 0.46) experienced peritonitis and the number of patient-months on CAPD per episode of peritonitis were consistently greater. When the double bag systems were compared with the Y-set systems significantly fewer patients experienced peritonitis (OR 0.44, 95% CI 0.27 to 0.71) and the numbers of patient-months on CAPD/ episode of peritonitis were also greater.

REVIEWER'S CONCLUSIONS

Double bag systems should be the preferred exchange systems in CAPD.