Measurement of Isfahan heavy water zero-power reactor kinetic parameters using advanced pulsed neutron source method in a near critical state

The pulsed neutron source (PNS) technique was used to determine the prompt neutron decay constant for two different lattice pitches in the HWZPR heavy water zero power reactor. The results were compared to the variance-to-mean ratio (VTM) method. The neutron mean generation time was also calculated for both pitches, and the results were compared to previous Monte Carlo calculations. The findings of this research can be used as a benchmark nuclear codes to validate kinetic parameters.

Long-Term Safety and Efficacy of Programmable Implantable Insulin Delivery Systems

Objectives

Since only short-term studies of continuous intraperitoneal insulin infusion (CIPII) therapy using implantable programmable insulin delivery systems have been performed to show this method of diabetes therapy to be safe and efficacious, we have performed long-term studies to assess its safety and efficacy.

Research design and methods

For 78 patient-years of follow-up, we have longitudinally studied the incidence of diabetic ketoacidosis and severe hypoglycemia in 25 type 1 diabetic patients treated with CIPII. We also compared, cross-sectionally, the long-term safety and efficacy of CIPII to intensive subcutaneous insulin therapy using intermittent injections or continuous subcutaneous insulin infusion. Finally, we examined the relationship between glycated hemoglobin levels and the standard deviation of daily blood glucose excursion.

Results

Cross-sectional analysis revealed similar degrees of metabolic control accompanied by significantly decreased rates of both ketoacidosis (0.013 events/patient/year) and severe hypoglycemia (0.05 events/patient/year) during CIPII compared to intermittent injections and continuous subcutaneous insulin infusion therapy. A four-fold decrease in the rate of severe hypoglycemia was observed during longitudinal comparison of pre- and post-implantation complication rates. A relationship was also shown between decreased levels of mean glycated hemoglobin and the standard deviation of blood glucose excursions during CIPII therapy.

Conclusions

Our data demonstrate that long-term therapy with CIPII is as effective as other methods in achieving near-normal levels of glycated hemoglobin, which in CIPII is associated with a decreased standard deviation of blood glucose excursions. Further, CIPII using implantable programmable insulin delivery systems is the safest method described for intensive insulin therapy in home blood glucose monitoring type 1 diabetic patients.

Effect of ligand-activated estrogen receptor β on lymphoma growth in vitro and in vivo

Estrogen receptor β (ERβ) is expressed in immune cells and studies have suggested an antiproliferative function of ERβ. We detected ERβ expression in murine T- and human B-cell lymphoma cell lines and analyzed the effects of estradiol and selective ERβ agonists on lymphoma growth in culture and in vivo. Treating the cells with estradiol had minor effects on cell growth, whereas the selective ERβ agonists diarylpropionitrile (DPN) and KB9520 showed a strong antiproliferative effect. When grafting mice with murine T-cell lymphoma cells, male mice developed larger tumors compared with female mice, a difference that was abolished following ovariectomy, showing estrogen-dependent growth in vivo. To investigate whether lymphoma growth may be inhibited in vivo by ERβ agonist treatment, mice grafted with murine lymphoma cells were treated with DPN or KB9520. Both ERβ-selective agonists strongly inhibited lymphoma growth. The reduced tumor size seen following either DPN or KB9520 treatment was due to reduced proliferation and increased apoptosis. Our results show an ERβ ligand-dependent antiproliferative effect of lymphoma cells expressing endogenous ERβ and that lymphoma cell growth in vivo can efficiently be inhibited by ERβ agonists. This suggests that ERβ agonists may be useful in the treatment of lymphomas.

Population pharmacokinetics of oral high-dose busulfan in adult patients undergoing hematopoietic stem cell transplantation

BACKGROUND AND THE PURPOSE OF THE STUDY

Many factors have been reported that contribute to the wide intra- and inter-patient variability of Busulfan (Bu) disposition. The purpose of this study was to develop a population pharmacokinetic model and to determine the covariates affecting the pharmacokinetics (PK) of Bu in Iranian adult patients who received oral high-dose as a conditioning regimen before Hematopoietic Stem Cell Transplantation (HSCT).

METHODS

A population PK analysis was performed in 30 patients who received an oral Bu and cyclophosphamide regimen before HSCT. Bu was given orally according to the protocol of the institution. In order to prevent seizures caused by Bu, phenytoin was administered orally one hour before each dose of Bu.A total of 180 blood samples were analyzed by HPLC and PK parameters were estimated by the non-linear mixed effect model by MONOLIX 3.1 program. A one-compartment model with an additive error model was used to describe the concentration-time profile of Bu.

RESULTS

Patients' disease and weight was found to be the determinant factors for clearance (CL) and the volume of distribution (Vd) according to Monolix analysis. The covariate entered in final model followed by these equations:[Formula: see text][Formula: see text] In this limited study, the age (15-43 years) had no significant effect. For a patient weighting 60 kg, the typical CL and Vd were estimated to be 13.4 l/hr and 42.6 L, respectively. The interindividual variability of CL and Vd were 13.6 and 6.3%, respectively. There was no significant metabolic induction in these four days as is evident by comparing the trough levels of Bu. However it should be mentioned that, one tailed t-test p-values of the days of two and three, two and four and three and four were 0.083, 0.069 and 0.388, respectively.

MAJOR CONCLUSIONS

Results of this study showed that the type of disease was a determinant of CL and the weight of patient was a determinant of Vd for Bu population PK parameters. A reliable PK parameters and Css, estimated from only one plasma concentrations (5 hrs after the first dose), were validated. Since these methods require few sampling and are easy to be used, the limited sampling methods might be advantageous in the routine clinical practice.

A Novel Tumour-Based Test To Identify Breast Cancer Due to BRCA1 and BRCA2 Mutations

Background: Family history and young onset are the usual indicators of an underlying genetic predisposition to breast cancer development. BRCA1 associated breast tumours are more likely to be ER negative and express “basal” markers, however most patients with ER negative/ basal marker positive breast cancers (especially young onset) do not have inherited BRCA1 mutations. BRCA1 and BRCA2 gene carriers may have novel treatment options available and may need to consider future cancer prevention strategies. Genetic counselling and germline mutation analysis remains a relatively expensive option that is not appropriate for most breast cancer patients.Aim: To design a sensitive and specific pathology based predictor that would improve identification of BRCA1 and 2 gene carriers.Method: We assembled a training panel of breast cancer tumour blocks from 67 BRCA1, 71 BRCA2 associated and 105 sporadic young onset cases (≤ 40 years at diagnosis). All gene carriers were diagnosed before 50 years and were matched to sporadic cases for ER status. Tissue micro arrays (TMAs) were assembled and subjected to immunohistochemical analysis with a panel of 18 antibodies. DNA was extracted from micro dissected tumour tissue and matched patient lymphocytes and subjected to high resolution tiling path microarray-based Comparative Genomic Hybridisation (aCGH). Using robust statistical approaches, regions significantly differentially lost, gained or amplified in BRCA1, BRCA2 and controls were identified. Probes for chromogenic in situ hybridisation (CISH) for amplified regions were generated.Results: Two differentially amplified clones in BRCA1 cases designated P1 at 3q25.31 and P2 at 3q25.2 and one in BRCA2 cases, P3 at 20q13.13, were identified and amplifications validated in the training set using CISH. Logistic regression analysis of the panel comprising CISH and IHC markers was used to develop the best predictor. The best predictor for BRCA1 gene carriers was a combination of P1, ER and HER2. This combination outperformed all combinations of immunohistochemical markers, including ER and basal markers; the Positive Predictive Value (PPV) was 87.5% and NPV 92% giving a Receiver Operator Characteristic (ROC) curve with an AUC of 0.92 (CI 0.88-0.97). The BRCA2 signature panel is currently being evaluated. These BRCA1 and BRCA2 predictor panels are being validated in a new set of TMAs comprising 223 tumours from the POSH study1.Conclusion: This tumour based predictor for BRCA1 and BRCA2 carriers may prove useful to identify gene carriers at low a priori chance of having a mutation, to direct BRCA1/2 targeted treatment approaches and to identify familial non BRCA1/2 cases that may be suitable for new gene discovery studies.1. Eccles D et al. BMC Cancer 2007; 7(1):160.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5032.

Genomic and immunophenotypical characterization of pure micropapillary carcinomas of the breast

Pure invasive micropapillary carcinoma (MPC) is a special histological type that accounts for 0.7-3% of all breast cancers. MPC has a distinctive growth pattern and a more aggressive clinical behaviour than invasive ductal carcinomas of no special type (IDC-NSTs). To define the molecular characteristics of MPCs, we profiled a series of 12 MPCs and 24 grade and oestrogen receptor (ER)-matched IDC-NSTs using high-resolution microarray comparative genomic hybridization (aCGH). In addition, we generated a tissue microarray containing a series of 24 MPCs and performed immunohistochemical analysis with ER, PR, Ki-67, HER2, CK5/6, CK14, CK17, EGFR, topoisomerase-IIalpha, cyclin D1, caveolin-1, E-cadherin, and beta-catenin antibodies. In situ hybridization probes were employed to evaluate the prevalence of amplification of HER2, TOP2A, EGFR, CCND1, MYC, ESR1, and FGFR1 genes. aCGH analysis demonstrated that MPCs significantly differed from IDC-NSTs at the genomic level. Gains of 1q, 2q, 4p, 6p, 6q23.2-q27, 7p, 7q, 8p, 8q, 9p, 10p, 11q, 12p, 12q, 16p, 17p, 17q, 19p, 20p, 20q, and 21q, and losses of 1p, 2p, 6q11.1-q16.3, 6q21-q22.1, 9p, 11p, 15q, and 19q were more prevalent in MPCs. High-level gains/amplifications of 8p12-p11, 8q12, 8q13, 8q21, 8q23, 8q24, 17q21, 17q23, and 20q13 were significantly associated with MPCs. A comparison between 24 MPCs and a series of 48 grade and ER-matched IDC-NSTs revealed that high cyclin D1 expression, high proliferation rates, and MYC (8q24) amplification were significantly associated with MPCs. Our results demonstrate that MPCs have distinct histological features and molecular genetic profiles supporting the contention that they constitute a distinct pathological entity.

First-line treatment of acute promyelocytic leukemia with arsenic trioxide without ATRA and chemotherapy

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Background: Standard treatment of APL is ATRA plus chemotherapy but Arsenic Trioxide (ATO) is most potent single agent against APL cells. Role of ATO in first line therapy of APL needs to clarify. Methods: Between may 2000 and September 2006,we treated 141 new cases of APL(Median age 28±12.8 y/o min=11,max=71) by 2 hours iv infusion of 0.15mg/kg ATO until complete remission. Trial approved by IRB and consent form obtained. Diagnosis was by clinical and morphologic characteristics and confirmed by cytogenetic and RT-PCR for detection of t(15,17) and presence of PML-RARa. After complete remission patients received consolidation by 28 days infusion of ATO for one or four courses.(one consolidation one month after CR and for some patients second, third and forth consolidations one month after first one and two another , one year and two year after CR) Results: : complete remission observed in 121 cases(85.8%) and early mortality rate was14.9%(most common cause of early mortality was APL syndrome,61.9%).Median follow up was 28 months. For patients who achieve to complete remission,one, two and three year disease free survival were 95.6%± 2%, 76.9±4% and 57± 6%,respectively. Many relapsed patients salvaged again with ATO alone so, two and three years overall survival for this cohort was 95.6%±2% and 83.7%±4%. Increasing number of consolidation from one to four couldn’t increase DFS or OS in one and two years after CR. Conclusions: ATO is effective in treatment of new cases of APL. Introduction of ATO in first line treatment of APL(with or without ATRA plus chemotherapy) needs a multi center randomized clinical trial.

No significant financial relationships to disclose.

Fludarabine and busulfan as a myeloablative conditioning regimen for allogeneic stem cell transplantation in high- and standard-risk leukemic patients

Busulfan and cyclophosphamide (BuCy) are currently the most widely used myeloablative regimen to treat malignancies with allogeneic stem cell transplantation. Fludarabine has considerable efficacy in both immunosuppression and tumor cells killing with a minimal extramedullary toxicity. We evaluated the efficacy of 40 mg/m(2) fludarabine i.v. for 5 days and busulfan 4 mg/kg/day p.o. for 4 days as myeloablative conditioning regimen in 70 patients (median age 24 years) with acute leukemia or chronic phase of myelogenous leukemia. They all had human leukocyte antigen-matched sibling donors. The patients received 10 mug/kg granulocyte colony stimulating factor (GCSF), 24 h after stem cell infusion until engraftment occurred. Graft-versus-host disease (GVHD) prophylaxis included 3 mg/kg cyclosporine-A i.v. from day -2 to +6 followed by 12 mg/kg p.o. until day +60. The median time of neutrophil recovery (>0.5 x 109/l) and platelet recovery (>20 x 109/l) were 10 and 12 days, respectively. Mucositis (93%) and hepatic toxicity (16%) resolved with conservative therapy. The incidence of acute GVHD grade I-II and III-IV were 38.6 and 15.7% respectively. Overall survival and disease-free survival were 71 and 64% respectively with 17 months median follow-up for surviving patients. We conclude that FluBu may be used as a substitute for BuCy with almost the same efficacy and with a lower transplant adverse effect but to increase anti-leukemic effects, especially in acute lymphoblastic leukemia patients, it needs some modifications.

Microarray-based comparative genomic hybridisation of breast cancer patients receiving neoadjuvant chemotherapy

We analysed the molecular genetic profiles of breast cancer samples before and after neoadjuvant chemotherapy with combination doxorubicin and cyclophosphamide (AC). DNA was obtained from microdissected frozen breast core biopsies from 44 patients before chemotherapy. Additional samples were obtained before the second course of chemotherapy (D21) and after the completion of the treatment (surgical specimens) in 17 and 21 patients, respectively. Microarray-based comparative genome hybridisation was performed using a platform containing approximately 5800 bacterial artificial chromosome clones (genome-wide resolution: 0.9 Mb). Analysis of the 44 pretreatment biopsies revealed that losses of 4p, 4q, 5q, 12q13.11-12q13.12, 17p11.2 and 17q11.2; and gains of 1p, 2p, 7q, 9p, 11q, 19p and 19q were significantly associated with oestrogen receptor negativity. 16q21-q22.1 losses were associated with lobular and 8q24 gains with ductal types. Losses of 5q33.3-q4 and 18p11.31 and gains of 6p25.1-p25.2 and Xp11.4 were associated with HER2 amplification. No correlations between DNA copy number changes and clinical response to AC were found. Microarray-based comparative genome hybridisation analysis of matched pretreatment and D21 biopsies failed to identify statistically significant differences, whereas a comparison between matched pretreatment and surgical samples revealed a statistically significant acquired copy number gain on 11p15.2-11p15.5. The modest chemotherapy-driven genomic changes, despite profound loss of cell numbers, suggest that there is little therapeutic selection of resistant non-modal cell lineages.

Array CGH profiling of favourable histology Wilms tumours reveals novel gains and losses associated with relapse

Despite the excellent survival of Wilms tumour patients treated with multimodality therapy, approximately 15% will suffer from tumour relapse, where response rates are markedly reduced. We have carried out microarray-based comparative genomic hybridisation on a series of 76 Wilms tumour samples, enriched for cases which recurred, to identify changes in DNA copy number associated with clinical outcome. Using 1Mb-spaced genome-wide BAC arrays, the most significantly different genomic changes between favourable histology tumours that did (n = 37), and did not (n = 39), subsequently relapse were gains on 1q, and novel deletions at 12q24 and 18q21. Further relapse-associated loci included losses at 1q32.1, 2q36.3-2q37.1, and gain at 13q31. 1q gains correlated strongly with loss of 1p and/or 16q. In 3 of 11 cases with concurrent 1p(-)/1q(+), a breakpoint was identified at 1p13. Multiple low-level sub-megabase gains along the length of 1q were identified using chromosome 1 tiling-path arrays. One such recurrent region at 1q22-q23.1 included candidate genes RAB25, NES, CRABP2, HDGF and NTRK1, which were screened for mRNA expression using quantitative RT-PCR. These data provide a high-resolution catalogue of genomic copy number changes in relapsing favourable histology Wilms tumours.

Genome-wide screening for genetic changes in a matched pair of benign and prostate cancer cell lines using array CGH

Copy number alterations in a matched pair of benign epithelial and prostate cancer cell lines derived from the same patient were assessed using array-based comparative genomic hybridisation (aCGH). The cancer cell line showed a gain of chromosome 7, deletion of chromosome 8, gains (including high level) and losses on chromosome 11, loss of 18p and gain of 20q. Deletions on chromosome 8 were confirmed with microsatellite markers. The aCGH results were compared to gene expression data obtained using DNA microarrays and suggested the involvement of caspases and ICEBERG on 11q and E2F1 on chromosome 20q.

Treatment of acute promyelocytic leukemia with arsenic trioxide without ATRA and/or chemotherapy

INTRODUCTION

Arsenic trioxide is effective and approved for treatment of relapsed or refractory acute promyelocytic leukemia (APL) cases resistant to all-trans retinoic acid (ATRA), but its effect on new cases of APL is not clear.

MATERIALS AND METHODS

We studied 111 patients with APL. Arsenic trioxide was infused at 0.15 mg/kg daily dose, until complete remission was achieved. Then, after 28 days of rest, arsenic trioxide was infused daily for 28 days as consolidation therapy. We studied minimal residual disease (MRD) by semi-sensitive reverse transcription polymerase chain reaction (RT-PCR) on peripheral blood samples.

RESULTS

Complete remission was observed in 95 patients (85.6%). With the median (range) follow-up period of 16.5 (1-57) months, 1- and 2-year disease-free survival was 88.3% and 63.7%, respectively; 24 patients relapsed, 19 of whom achieved a second complete remission, again by arsenic trioxide. Third and fourth remissions were seen in some relapsed patients, again by arsenic trioxide. For patients in complete remission, 1- and 3-year survival was 95.5% and 87.6%, respectively. MRD was positive in four (8.3%) out of 48 cases during 1 year after remission induction; three of them relapsed clinically.

CONCLUSIONS

Arsenic trioxide is effective as first-line treatment for APL. Results of arsenic trioxide combination therapy with chemotherapy/ATRA requires further study.

Cyclosporin A and mini short-term methotrexate vs cyclosporin A as graft-versus-host disease prophylaxis in patients with beta thalassemia major undergoing allogeneic blood and marrow transplantation

We compared the effects of cyclosporin A (CsA) alone as graft-versus-host disease (GVHD) prophylaxis vs cyclosporine with short-course methotrexate (MTX) in patients with thalassemia. In all, 140 patients were enrolled in this study. The first group, of 50 patients, received CsA alone at 3 mg/kg i.v. from day -2 to +5 followed by 12.5 mg/kg p.o., which was tapered according to the patient's condition. The other group, of 90 patients, received the combination of CsA+MTX in which CsA was used with the above-mentioned dose and MTX was on 10 mg/m(2) day +1 and 6 mg/m(2) on days +3 and +6. Incidence of acute GVHD grade II-IV in the CsA group was 78% and in the CsA+MTX group was 52.2%, which was statistically significant (P=<0.001). There were no significant differences in the incidence of chronic GVHD between the two groups. The mean neutrophil engraftment to 0.5 x 10(9)/l was 14 and 23 days for CsA group and CsA+MTX group, respectively (P=<0.001). There were no significant differences for platelet recovery between the two groups. Graft failure in the CsA and CsA+MTX groups was seven (14%) and nine (10%) patients, respectively (P=0.58). Overall survival in the CsA and CsA+MTX groups was 77 and 85%, respectively. Disease-free survival in the CsA and CsA+MTX groups were 58 and 80%, respectively.

Esophageal cancer in Iran

Esophageal cancer is among the 10 most frequent cancers in the world. Iran is one of the known areas with a high incidence of esophageal cancer. Most of the patients in Iran have been reported from the north and northeast regions of the country. In one survey by the Iran Cancer Institute, 9% of all cancers and 27% of gastrointestinal cancers were esophageal carcinoma. The male to female ratio was 1.7/1. The distal portion of the esophagus is involved more often than other parts. Consumption of wheat flour, exposure to residues from opium pipes, drinking hot tea, and chewing nass (a mixture of tobacco, lime, ash, and other ingredients) are the suspect etiologic agents for esophageal cancer in Iran. Dysphagia, weight loss, anorexia, abdominal pain, and odynophagia are the common symptoms and signs of Iranian patients with esophageal cancer. For clinical staging, chest computed tomographic scanning is performed. Adenocarcinoma of the esophagus is not as common in Iran as in western countries. Public education, nutritional support, and eradication of opium addiction may decrease the morbidity and mortality that result from esophageal cancer. Surgery has traditionally been the mainstay of esophageal cancer treatment in Iran. Radiotherapy is mainly used postoperatively. The usual combination chemotherapy regimen is cisplatin plus flurouracil (5-Fu). Semin Oncol 28:153-157.

Methylation of the multi tumor suppressor gene-2 (MTS2, CDKN1, p15INK4B) in childhood acute lymphoblastic leukemia

The multi tumor suppressor genes MTS1 (CDKN2 p16INK4A) and MTS2 (CDKN1, p15INK4B) located at 9p21-22 are inactivated in some human cancers via several mechanisms including deletion and hypermethylation. We have investigated the deletion and methylation status of MTS1 and MTS2 in childhood acute lymphoblastic leukemia (ALL) of both T-cell (17 cases) and B-cell phenotypes (29 cases), and p16INK4A and p15INK4B mRNA expression in 36 of these cases. Biallelic or monoallelic loss of both MTS1 and MTS2 was observed in 12 cases of B-ALL and nine cases of T-ALL. Two cases of T-ALL showed deletion of MTS1 but not MTS2. The 5' CpG region of MTS2 was hypermethylated in 12 cases of precursor B-ALL and eight cases of T-ALL but no hypermethylation was found in the 5' CpG region of MTS1. All cases with homozygous deletion of MTS1 or MTS2 had no or low levels of mRNA expression and similar low levels of expression were found in cases in which MTS2 was present but fully methylated. Thus hypermethylation of MTS2, in contrast to MTS1, is frequent in childhood ALL. Furthermore our data show that although inactivation of MTS1 by deletion is common, inactivation of MTS2 by a combination of deletion and hypermethylation is more frequent in both B-ALL (20/29, 69%) and T-ALL (17/17, 100%). This suggests that both MTS1 and MTS2 are important targets of the 9p21-22 deletion.

Diagnostic procedures for catheter malfunction in programmable implantable intraperitoneal insulin infusion devices

OBJECTIVE

To evaluate the roles of 1) abdominal radiography, 2) a pressure diagnostic procedure (PDP) using a standardized diluent infusion into the catheter sideport, and 3) radiocontrast imaging of the catheter lumen as procedures for diagnosing catheter malfunction in diabetic patients implanted with a programmable intraperitoneal infusion device.

RESEARCH DESIGN AND METHODS

Sixteen type I diabetic patients implanted with Infusaid programmable intraperitoneal insulin pumps were studied. The ability of the above three procedures to assist diagnosis of catheter malfunction and distinguish between occlusion and catheter breakage was retrospectively analyzed. Glycated hemoglobin was measured to determine the clinical importance of catheter malfunctions and decreases in pump flow due to insulin aggregation in the pump chamber.

RESULTS

Mean glycated hemoglobin levels increased significantly from 8.0 +/- 0.3 to 9.0 +/- 0.4% (P < 0.05) before and after catheter malfunction, but not during pump flow slowdowns. Mean peak pressure during PDP was 1.96 +/- 0.14 psi (P < 0.01 vs. normal) in reversibly occluded catheters and 1.86 +/- 0.35 psi (P < 0.05 vs. normal) in broken catheters, compared with 1.32 +/- 0.23 psi in normal catheters. Decay times during PDP were > 50 s for both reversibly occluded and broken catheters (P < 0.001 vs. normal of 3.6 +/- 0.82 s). Abdominal radiographs and sideport injections of contrast material were used to distinguish the types of broken catheters.

CONCLUSIONS

Catheter breakage and occlusion are complications in implantable insulin infusion systems and result in metabolic deterioration. The presence of a sideport allows pressure data and radiographic procedures to assist in determining the cause of catheter malfunction. A diagnostic algorithm was generated to improve efficiency in investigating catheter problems.

Insulin antibody responses after long-term intraperitoneal insulin administration via implantable programmable insulin delivery systems

OBJECTIVE

To determine whether insulin antibodies are generated in diabetic patients after short- and long-term intraperitoneal insulin use and, if so, whether they are of potential clinical interest. Insulin antibodies commonly develop in diabetic patients who use subcutaneous human insulin, although their clinical significance remains controversial. Few data are available regarding insulin antibody responses to intraperitoneal insulin.

RESEARCH DESIGN AND METHODS

We studied insulin antibody levels and clinical diabetes control in 25 type 1 diabetic patients treated for 3-6 years with intraperitoneal surfactant-stabilized porcine modified human insulin delivered by implantable programmable insulin delivery systems.

RESULTS

All patients had preimplantation insulin antibody levels < 20 microU/ml, with a mean value of 2 +/- 2 microU/ml (1 SD). Mean antibody levels increased throughout the study period to a mean maximum of 197 +/- 326 microU/ml (P < 0.02) with 11 of 25 (44%) patients' levels exceeding 20 microU/ml (insulin responders). The mean time to significant antibody development was 21.8 +/- 4.4 months. Of the 11 responder patients, 4 had clinical syndromes that consisted of increasing daily insulin requirements and/or nocturnal hypoglycemia despite minimal nighttime basal insulin infusion rates associated with peak antibody levels > 200 microU/ml. None of the nonresponder patients (antibody levels < 20 microU/ml) had these clinical findings.

CONCLUSIONS

Our results indicate that insulin antibody levels observed during intraperitoneal administration of human insulin are 1) similar to those reported during subcutaneous administration; although the rise in antibody level may be delayed compared with subcutaneous human insulin, 2) associated with a patient subset who are insulin antibody responders after switching from subcutaneous to intraperitoneal human insulin, 3) associated with a decrease in levels among responder patients regardless of whether they discontinue or continue pump use, and 4) associated with increased insulin needs and/or nocturnal hypoglycemia despite minimal basal rate insulin infusion at nighttime when antibody levels exceed 200 microU/ml.

Long-term safety and efficacy of programmable implantable insulin delivery systems

OBJECTIVES

Since only short-term studies of continuous intraperitoneal insulin infusion (CIPII) therapy using implantable programmable insulin delivery systems have been performed to show this method of diabetes therapy to be safe and efficacious, we have performed long-term studies to assess its safety and efficacy.

RESEARCH DESIGN AND METHODS

For 78 patient-years of follow-up, we have longitudinally studied the incidence of diabetic ketoacidosis and severe hypoglycemia in 25 type 1 diabetic patients treated with CIPII. We also compared, cross-sectionally, the long-term safety and efficacy of CIPII to intensive subcutaneous insulin therapy using intermittent injections or continuous subcutaneous insulin infusion. Finally, we examined the relationship between glycated hemoglobin levels and the standard deviation of daily blood glucose excursion.

RESULTS

Cross-sectional analysis revealed similar degrees of metabolic control accompanied by significantly decreased rates of both ketoacidosis (0.013 events/patient/year) and severe hypoglycemia (0.05 events/patient/year) during CIPII compared to intermittent injections and continuous subcutaneous insulin infusion therapy. A four-fold decrease in the rate of severe hypoglycemia was observed during longitudinal comparison of pre- and post-implantation complication rates. A relationship was also shown between decreased levels of mean glycated hemoglobin and the standard deviation of blood glucose excursions during CIPII therapy.

CONCLUSIONS

Our data demonstrate that long-term therapy with CIPII is as effective as other methods in achieving near-normal levels of glycated hemoglobin, which in CIPII is associated with a decreased standard deviation of blood glucose excursions. Further, CIPII using implantable programmable insulin delivery systems is the safest method described for intensive insulin therapy in home blood glucose monitoring type 1 diabetic patients.