Release and pharmacokinetics of near-infrared labeled albumin from monodisperse poly(d,l-lactic-co-hydroxymethyl glycolic acid) microspheres after subcapsular renal injection.

Subcapsular renal injection is a novel administration method for local delivery of therapeutics for the treatment of kidney related diseases. The aim of this study was to investigate the feasibility of polymeric microspheres for sustained release of protein therapeutics in the kidney and study the subsequent redistribution of the released protein. For this purpose, monodisperse poly(d,l-lactic-co-hydroxymethyl glycolic acid) (PLHMGA) microspheres (40 µm in diameter) loaded with near-infrared dye-labeled bovine serum albumin (NIR-BSA) were prepared by a membrane emulsification method. Rats were injected with either free NIR-BSA or with NIR-BSA loaded microspheres (NIR-BSA-ms) and the pharmacokinetics of the released NIR-BSA was studied for 3 weeks by ex vivo imaging of organs and blood. Quantitative release data were obtained from kidney homogenates and possible metabolism of the protein was investigated by SDS-PAGE analysis of the samples. The ex vivo images showed a rapid decrease of the NIR signal within 24h in kidneys injected with free NIR-BSA, while, importantly, the signal of the labeled protein was still visible at day 21 in kidneys injected with NIR-BSA-ms. SDS-PAGE analysis of the kidney homogenates showed that intact NIR-BSA was released from the microspheres. The locally released NIR-BSA drained to the systemic circulation and subsequently accumulated in the liver, where it was degraded and excreted renally. The in vivo release of NIR-BSA was calculated after extracting the protein from the remaining microspheres in kidney homogenates. The in vivo release rate was faster (89 ± 4% of the loading in 2 weeks) compared to the in vitro release of NIR-BSA (38 ± 1% in 2 weeks). In conclusion, PLHMGA microspheres injected under the kidney capsule provide a local depot from which a formulated protein is released over a prolonged time-period.

Biocompatibility of poly(D,L-lactic-co-hydroxymethyl glycolic acid) microspheres after subcutaneous and subcapsular renal injection.

Poly(D,L-lactic-co-hydroxymethyl glycolic acid) (PLHMGA) is a biodegradable copolymer with potential as a novel carrier in polymeric drug delivery systems. In this study, the biocompatibility of PLHMGA microspheres (PLHMGA-ms) was investigated both in vitro in three different cell types (PK-84, HK-2 and PTECs) and in vivo at two implantation sites (by subcutaneous and subcapsular renal injection) in rats. Both monodisperse (narrow size distribution) and polydisperse PLHMGA-ms were prepared with volume weight mean diameter of 34 and 17 µm, respectively. Mono and polydisperse PLHMGA-ms showed good cytocompatibility properties upon 72 h incubation with the cells (100 µg microspheres/600 µL/cell line). A mild foreign body reaction was seen shortly after subcutaneous injection (20 mg per pocket) of both mono and polydisperse PLHMGA-ms with the presence of mainly macrophages, few foreign body giant cells and myofibroblasts. This transient inflammatory reaction diminished within 28 days after injection, the time-point at which the microspheres were degraded. The degradation profile is comparable to the in vitro degradation time of the microspheres (i.e., within 35 days) when incubated at 37 °C in phosphate buffered saline. Subcapsular renal injection of monodisperse PLHMGA-ms (10 mg) in rats was characterized with similar inflammatory patterns compared to the subcutaneous injection. No cortical damage was observed in the injected kidneys. In conclusion, this study demonstrates that PLHMGA-ms are well tolerated after in vivo injection in rats. This makes them a good candidate for controlled delivery systems of low-molecular weight drugs as well as protein biopharmaceuticals.

Microsphere size influences the foreign body reaction.

Biodegradable poly-(DL-lactide-co-glycolide) (PLGA) microspheres (MSP) are attractive candidate vehicles for site-specific or systemic sustained release of therapeutic compounds. This release may be altered by the host's foreign body reaction (FBR), which is dependent on the characteristics of the implant, e.g. chemistry, shape or size. In this study, we focused on the characterisation of the influence of MSP size on the FBR. To this end we injected monodisperse MSP of defined size (small 5.8 µm, coefficient of variance (CV) 14 % and large 29.8 µm, CV 4 %) and polydisperse MSP (average diameter 34.1 µm, CV 51 %) under the skin of rats. MSP implants were retrieved at day 7, 14 and 28 after transplantation. The FBR was studied in terms of macrophage infiltration, implant encapsulation, vascularisation and extracellular matrix deposition. Although PLGA MSP of all different sizes demonstrated excellent in vitro and in vivo biocompatibility, significant differences were found in the characteristics of the FBR. Small MSP were phagocytosed, while large MSP were not. Large MSP occasionally elicited giant cell formation, which was not observed after implantation of small MSP. Cellular and macrophage influx and collagen deposition were increased in small MSP implants compared to large MSP. We conclude that the MSP size influences the FBR and thus might influence clinical outcome when using MSP as a drug delivery device. We propose that a rational choice of MSP size can aid in optimising the therapeutic efficacy of microsphere-based therapies in vivo.

Explorations of the application of cyanine dyes for quantitative alpha-synuclein detection.

We examined the practical aspects of using fluorescent mono (T-284) and trimethinecyanine (SH-516) dyes for detecting and quantifying fibrillar alpha-synuclein (ASN). We studied the interaction of cyanine dyes with fibrillar proteins using fluorescence spectroscopy and atomic force microscopy. The commercially available classic amyloid stain thioflavin T (Thio T) was used as the reference dye. T-284 and SH-516 dyes can be used for fluorometric quantification of fibrillar wild-type ASN at concentrations of approximately 1.5-20 microg/ml. Both dyes appeared suitable for step-wise monitoring of ASN variants (wild-type and mutants A30P and A53T) aggregation into fibrils in vitro, demonstrating good reproducibility, exceeding that for the commonly used Thio T. Our assay may be used for screening in vitro of agents capable of affecting the aggregation of ASN. In addition, T-284 and SH-516 cyanine dyes were shown to recognize amyloid proteins of various amino acid compositions selectively. T-284 demonstrated particular sensitivity to wild-type and A53T ASN, while for SH 516, the fluorescence response to fibrillar proteins was nearly the same except for lysozymes. T-284 and SH-516 cyanine dyes are sensitive and specific fluorescent probes for monitoring ASN fibril formation process in vitro, quantification of fibrillar ASN in solution, and fluorescent detection of various fibrillar protein species.

New developments in staging and follow-up of patients with Hodgkin's lymphoma.

Adequate staging of newly diagnosed patients with Hodgkin's lymphoma enables optimal treatment planning, which is of particular importance for finding a balance between treatment efficacy and toxicity. In this review an overview is given of the current knowledge on initial staging and the role of imaging modalities during and after treatment. A promising new tool is whole-body positron emission tomograpy (PET) scanning with fluorodeoxyglucose (FDG). This modality is particularly useful for the evaluation of a residual mass at the end of treatment and for the assessment of the prognostically relevant 'early response' to chemotherapy. Although high survival rates have been reported for patients treated within the context of clinical trials these rates are generally lower in population-based series. In the general population comorbidity is present in half of all elderly Hodgkin patients. Since comorbidity has great impact on treatment planning and survival, this prognostic factor should be taken into account in future trials.

Proposal and evaluation of a Monte Carlo model for hair regrowth following plucking.

BACKGROUND/AIMS: The efficacy of single or multiple hair removal treatments reveals a number of properties of the hair follicle, such as the phase in the growing cycle and the hair growth speed. The aim of the present study was to provide a method to evaluate the results of hair removal treatments, in particular plucking, in order to obtain insight into some properties of the follicle and to propose a strategy for optimal treatment. Our hypothesis is that plucking of anagen hairs may result in either reset of the follicle to telogen, in mild damage to the follicle, resulting in a temporary reduction of the mitotic activity, or in an unaffected follicle, so that the hair continues to grow. METHODS: The regrowth of hairs after plucking was measured as a function of time for a number of subjects. Individual leg hairs within the areas observed were followed over time. Besides this, the growth speed of leg hairs was measured, and the extracted anagen hair length was determined to obtain an estimate of the anagen follicle depth on the leg. Monte Carlo simulations of the hair plucking and regrowth process were performed after the experiments. Some parameters derived from the experiments were used as inputs; others were fitted to achieve a good correlation between the result of the simulations and the experiments. Finally, the Monte Carlo routine was used to investigate the influence of the time interval between multiple plucking treatments. RESULTS: The regrowth of hairs after plucking, the growth speed and the extracted anagen hair length were measured. Both experiments and Monte Carlo simulations indicated that the result of plucking of an anagen hair is not limited to reset of the follicle to telogen or continued hair growth, but that a temporary reduction of the mitotic activity is very likely to occur. Finally, a linear relationship between the interval between epilation treatments and the average number of hairs on the skin was found using the Monte Carlo simulation. CONCLUSIONS: The combination of experiments and Monte Carlo simulations is a very successful strategy for studying hair removal and hair (re)growth in detail.

Mechano-optical waveguide on-off intensity modulator.

High-extinction on-off modulators are essential for channel selection in integrated-optical sensor arrays. We report a standard SiON-technology-based electrostatically driven integrated mechano-optical waveguide on-off intensity modulator. On-off modulation is achieved by movement of an absorbing element into and out of the evanescent field of the guided mode. An extinction ratio of >37 dB at an actuation voltage of <30 V was achieved in a 6 mm x 4 mm device for a wavelength of 632.8 nm. Full wafer-scale fabrication is made possible by use of chemical mechanical polishing and aligned wafer bonding.

Paclitaxel, ifosfamide and cisplatin with granulocyte colony-stimulating factor or recombinant human interleukin 3 and granulocyte colony-stimulating factor in ovarian cancer: a feasibility study.

The tolerability and efficacy of four courses of paclitaxel and ifosfamide plus cisplatin every 3 weeks was evaluated in patients with residual or refractory ovarian cancer. Additionally, supportive haematological effects of recombinant human interleukin 3 (rhIL-3) and recombinant human granulocyte colony-stimulating factor (G-CSF) were studied. Paclitaxel starting dose was 135 mg m(-2) (day 1), with ifosfamide dose 1.2 g m(-2) day(-1) (days 2-4) and cisplatin dose 30 mg m(-2) day(-1) (days 2-4). All 16 patients received 5.0 microg kg(-1) day(-1) G-CSF (days 7-16) and, in addition, eight patients were randomized to receive 10 microg kg(-1) day(-1) rhIL-3 (days 5-9). Paclitaxel and ifosfamide doses were reduced when grade IV haematological toxicity occurred. In the absence of grade IV haematological toxicity and normal recovery of haematopoiesis, paclitaxel dose was escalated. Toxicity was evaluable in 56 courses, with haematological effects in 52. Despite antiemetic treatment, nausea and vomiting (> or = grade I) occurred in 50 courses. Five patients had persisting peripheral neuropathy. Renal and liver function were not affected. Grade IV neutropenia occurred in 12 out of 52 courses, with neutropenic fever in two patients, both of whom died from fatal septicaemia. Grade IV thrombocytopenia without bleeding was observed in 15 courses. Grade IV haematological toxicity was associated with hepatic metastases and concurrent increases in alkaline phosphatase (P <0.001) and gamma-glutamyltransferase (P=0.007). No relation was found between haematological toxicity and pharmacokinetic parameters of paclitaxel. Patients treated with rhIL-3 showed a tendency to a faster platelet recovery (not affecting platelet nadir), and the cisplatin dose intensity was higher (P=0.025). Six of the nine evaluable patients had a tumour response. The overall median progression-free survival was 7 months and the overall mean survival was 13 months. In conclusion, this potentially interesting combination as second-line treatment showed a low tolerability with unexpected mortality, while rhIL-3 administration tended to induce a more rapid platelet recovery.

A case of localized Castleman's disease with systemic involvement: treatment and pathogenetic aspects.

A patient is presented who had Castleman's disease with constitutional symptoms, a palpable supraclavicular/ axillar mass, and a microcytic anemia, among other laboratory abnormalities, including elevated levels of interleukin-6. Treatment consisted of irradiation of the involved area, with subsequent disappearance of all symptoms and normalization of the laboratory abnormalities. Iron kinetic studies demonstrated a hypoproliferative erythropoiesis, which normalized after radiotherapy. Hypoproliferative erythopoiesis could not be ascribed to serum inhibitors, since normal burst-forming units were observed in the absence or presence of autologous serum. The role of interleukin-6 in relation to Castleman's disease is highlighted.

Potential use of recombinant human interleukin-6 in clinical oncology.

Recombinant human IL-6 (rhIL-6) is a pleiotropic cytokine with stimulatory actions on the hematopoietic system, the immune system and hepatocytes. Clinical interest in the use of this cytokine was raised because of its thrombopoietic properties and also because of its anti-tumor activity, which was shown in vitro and in the preclinical setting. Various studies show that doses up to 10 mu kg/kg/d rhIL-6 before and after chemotherapy are tolerable and the most frequent side-effects encountered consist of flu-like symptoms. Furthermore, a consistent decrease in hemoglobin was reported during rhIL-6 treatment. This was probably due to hemodilution, although a change in ferrokinetics, may also at least partly, explain the anemia. An evident increase of platelets has been observed in various studies. After chemotherapy, rh-IL6 seemed to hasten platelet recovery, without affecting platelet nadir. Preliminary data from studies investigating the value of rhIL-6 as an anti-tumor agent in renal cell carcinoma and melanoma reported low response rates, between 8 and 14%. The results of rhIL-6 in ameliorating chemotherapy induced bone-marrow depression and especially thrombocytopenia, are promising and merit further phase III studies.

Toxicity and efficacy of escalating dosages of recombinant human interleukin-6 after chemotherapy in patients with breast cancer or non-small-cell lung cancer.

PURPOSE: To evaluate the safety, tolerability, and efficacy of varying doses of recombinant human interleukin-6 (rhIL-6) after chemotherapy. PATIENTS AND METHODS: In this phase I/II study, 19 breast (stage III to IV) or non-small-cell lung cancer (NSCLC) patients received mitoxantrone (10 mg/m2) and thiotepa (40 mg/m2) every 3 weeks, followed by rhIL-6 subcutaneously (days 5 to 15) at six dose levels: 0.5, 1.0, 2.5, 5.0, 10.0, and 20.0 micrograms/kg/d body weight/d (micrograms/kg/d). rhIL-6 was increased to the next level in the individual patient in case of incomplete bone marrow recovery (leukocyte count < 3 x 10(9)/L and/or platelet count < 100 x 10(9)/L at day 22) and/or platelet nadir less than 25 x 10(9)/L in two consecutive cycles. RESULTS: Flu-like symptoms were observed in most of the patients. Nausea and vomiting were reported in seven of 48 and 19 of 48 cycles, respectively. Dose-limiting toxicity at 20.0 micrograms/kg/d of rhIL-6 consisted of World Health Organization (WHO) grade 3 to 4 flu-like symptoms, nausea, and vomiting. Platelet recovery was faster in cycle 1 at 10.0 and 20.0 micrograms/kg/d of rhIL-6 than at lower dose levels (P < .05); thrombocytopenia grade 4 was observed at most levels. However, only two patients needed platelet transfusions (1.0 and 2.5 micrograms/kg/d rhIL-6). rhIL-6 effects on leukocytes were not dose-related, with a trend for the neutrophil nadir to increase with rhIL-6 up to 10 micrograms/kg/d. rhIL-6 dose escalation did not affect hematologic parameters and chemotherapy cycle duration. Hemoglobin (P < .001) and cholesterol (P < .05) levels decreased, while acute-phase proteins increased. CONCLUSION: rhIL-6 following chemotherapy is tolerable up to 10 micrograms/kg/d; flu-like symptoms and nausea were dose-limiting at 20 micrograms/kg/d. Platelet nadir did not differ for the various rhIL-6 doses. However, a faster platelet recovery was observed at 10.0 and 20.0 micrograms/kg/d of rhIL-6.

Phase II and pharmacokinetic study of lobaplatin in patients with relapsed ovarian cancer.

In phase I studies, lobaplatin showed activity in ovarian cancer patients pretreated with platinum. A phase II trial with lobaplatin was performed in patients with refractory or relapsed ovarian cancer to define activity and pharmacokinetics. Twenty-two patients were treated with lobaplatin administered as an intravenous bolus every 4 weeks. Dependent on creatinine clearance (CRCL) patients received 30 or 50 mg m-2 lobaplatin as the starting dose. Twenty-two patients received 78 courses (median 3, range 1-6). In eight patients total platinum (TPt) in plasma and urine, free platinum (FPt) in plasma ultrafiltrate (both measured by atomic absorption spectrometry) and lobaplatin in plasma ultrafiltrate measured (by high-performance liquid chromatography) were measured. Toxicity was confined to mild nausea and vomiting, mild leucocytopenia (WHO grade 3 in 18% of the courses), and renal function-related thrombocytopenia (WHO grade 3/4 in 53% of the courses). A correlation was found between CRCL and reduction in platelet count (r = -0.77; P < 0.01). No renal toxicity was encountered. Five of 21 evaluable patients (24%) achieved a response (four complete remissions and one partial remission). Remissions occurred mainly in patients who relapsed more than 6 months after primary treatment. The median survival from start of lobaplatin treatment was 8 months. The mean areas under the curve (AUCs) were 4.2 +/- 0.5, 3.0 +/- 0.6, and 3.2 +/- 1.1 h mgl-1 for TPt, FPt and lobaplatin respectively. The free platinum fraction (FPt/TPt) was initially very high, indicating low protein binding. FPt was essentially present as intact lobaplatin. Four hours after infusion 54 +/- 5% and 24 h after infusion 74 +/- 3% of the lobaplatin dose was excreted in the urine. In conclusion, lobaplatin is a platinum compound with anti-tumour activity in patients with relapsed ovarian cancer, especially in those who have platinum-sensitive tumours. The main toxicity of lobaplatin is thrombocytopenia and its dose should be corrected according to renal function.

Recombinant human interleukin-3 to dose-intensify carboplatin and cyclophosphamide chemotherapy in epithelial ovarian cancer: a phase I trial.

PURPOSE: To define the optimal dose of recombinant human interleukin-3 (rhIL-3) required to intensify the dose of carboplatin and cyclophosphamide for advanced epithelial ovarian cancer. PATIENTS AND METHODS: Seventeen patients were treated on day 1 with carboplatin (dose adjusted for creatinine clearance: range, 257 to 385 mg/m2; median, 300 mg/m2) and cyclophosphamide (750 mg/m2). rhIL-3 5 micrograms/kg/d (n = 10) or 10 micrograms/kg/d (n = 7) was administered subcutaneously (SC) on days 2 through 11. Carboplatin dose was escalated if no postponement of cycles 1 to 3 had occurred. RESULTS: A 3-week interval was achieved in 62% of cycles and a 4-week interval in 81%, with no difference between the rhIL-3 doses. A neutrophil nadir less than 0.5 x 10(9)/L occurred in 35% of the cycles at 5 micrograms/kg/d and in 52% at 10 micrograms/kg/d of rhIL-3 (nonsignificant difference). The mean platelet nadir in cycle 1 was 173 +/- 78 x 10(9)/L at 5 micrograms/kg/d and 340 +/- 152 x 10(9)/L at 10 micrograms/kg/d of rhIL-3 (P < .05), with a faster recovery of platelets at 10 micrograms/kg/d (P < .05). Progressive myelotoxicity occurred for leukocytes and platelets at both rhIL-3 doses and required chemotherapy postponement in later cycles. The planned six cycles were completed by 41% of patients. Fever (> or = 38.5 degrees C) occurred in 38% of cycles at 5 micrograms/kg/d and in 97% at 10 micrograms/kg/d (P < .0005); headache and myalgias occurred in 30% and 44%, respectively. After two cycles, diffuse erythema, facial edema, and urticaria were observed in two patients at 5 micrograms/kg/d and in five patients at 10 micrograms/kg/d of rhIL-3. This resolved after discontinuation of rhIL-3 and administration of corticosteroids and antihistamines. CONCLUSION: A dose of 5 micrograms/kg/d of rhIL-3 proved to be optimal to intensify the carboplatin and cyclophosphamide regimen. It permitted the administration of carboplatin and cyclophosphamide combination therapy every 3 weeks in 62% of cycles.