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1.
Eur J Cancer ; 197: 113470, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38096656

ABSTRACT

BACKGROUND: To determine whether the combination of nab-paclitaxel with gemcitabine has activity in patients with pretreated soft tissue sarcoma (STS). PATIENTS AND METHODS: NAPAGE is a phase Ib/II clinical trial investigating the combination of nab-paclitaxel (nab-pc) with gemcitabine employing two cohorts. One of a dose-de-escalation phase and one of expansion. In phase I, nab-pc was given at 150 mg/m2 in combination with gemcitabine 1000 mg/m2 every two weeks, until disease progression or unacceptable toxicity. This dose was recommended for phase II (RP2D), as there was no dose limiting toxicity (DLT) or discontinuations due to adverse events (AEs). The primary endpoint of the phase II was progression-free rate (PFR) at 3 months (H0: 20%, H1:40%). The secondary endpoints included progression free survival (PFS), overall survival (OS), AEs, objective response and patient-reported outcomes (PRO). Efficacy analysis was by intention to treat. RESULTS: The 3-month PFR was 56.4% (95% confidence interval CI: 39.6-72.2%). The 3-month and 6-month PFS were 58.4% (95% CI: 41.3-72.1%) and 44.6% (95% CI: 28.4-59.5%), respectively. Median PFS was 5.3 months (95% CI: 1.4-8.2) and median OS was 12.8 months (95% CI: 10.5-39.2). The most common treatment-related grade ≥ 3 AE were neutropenia (18%), followed by anemia (2.6%), hypertension (2.6%) and alanine aminotransferase increase (2.6%). Grade 1 and grade 2 peripheral sensory neuropathy (PNP) occurred in 15.4% and 20.5%, respectively. No grade 3-4 PNP was reported. CONCLUSIONS: Combining nab-pc and gemcitabine is safe. Promising activity is observed in pretreated STS patients with manageable toxicity. This regimen should be considered for further exploration.


Subject(s)
Pancreatic Neoplasms , Sarcoma , Humans , Albumins , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Deoxycytidine/therapeutic use , Gemcitabine , Paclitaxel/therapeutic use , Pancreatic Neoplasms/drug therapy , Sarcoma/drug therapy , Treatment Outcome
2.
Cancer Treat Rev ; 101: 102300, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34688105

ABSTRACT

BACKGROUND: A high number of combinations of PD-1/PD-L1 inhibitors with other anti-cancer therapies are in clinical development. The usefulness of phase II trials in evaluating their efficacy and safety is unclear. MATERIALS AND METHODS: We performed a systematic search on PubMed and Cochrane Library for phase II trials of PD-1/PD-L1 inhibitors in combination with other anti-cancer therapies (systemic therapy and/or radiotherapy) published between January 1st 2018 and December 31st 2020. Study design, primary endpoint and main outcomes were registered for each paper. RESULTS: 119 articles reporting on 65 regimens were included in our analysis. Backbone agents were more frequently PD-1 inhibitors (pembrolizumab = 47, nivolumab = 41, camrelizumab = 3) followed by anti-PD-L1 (durvalumab = 19, atezolizumab = 6, avelumab = 3). Therapeutic partners were other immunotherapeutic agents (n = 46), targeted therapies (n = 40), chemotherapy (n = 22) or radiotherapy (n = 11). The majority of articles reported on single-arm trials (n = 87, 73%) and response rate was the most frequent primary endpoint (n = 69, 58%). Objective responses, registered in 109 (92%) articles, ranged between 0% and 91%. The incidence of grade 3 or higher treatment-related adverse events, clearly reported in 97 (82%) articles, spanned from 0 to 100%. Five combinations received regulatory approval by Food and Drug Administration or European Medicine Agency for 9 different indications, based on the results of a phase II trial (n = 3) or on a confirmatory phase III trial (n = 6). CONCLUSIONS: The landscape of phase II trials evaluating PD-1/PD-L1 inhibitors with other anticancer therapies is heterogeneous. Combinations of two immunotherapeutic agents have been the most investigated. Only a minority of indications (8%) granted regulatory approval.


Subject(s)
Antineoplastic Agents/pharmacology , Immune Checkpoint Inhibitors , Immunotherapy/methods , Neoplasms , Radiotherapy/methods , Antineoplastic Protocols/classification , Clinical Trials, Phase II as Topic , Combined Modality Therapy/methods , Drug Development/methods , Humans , Immune Checkpoint Inhibitors/classification , Immune Checkpoint Inhibitors/pharmacology , Neoplasms/metabolism , Neoplasms/pathology , Neoplasms/surgery
3.
Drug Resist Updat ; 55: 100744, 2021 03.
Article in English | MEDLINE | ID: mdl-33551306

ABSTRACT

Ovarian cancer is the fifth cause of cancer-related deaths in women with high grade serous carcinoma (HGSOC) representing the most common histological subtype. Approximately 50 % of HGSOC are characterized by deficiency in homologous recombination (HR), one of the main cellular pathways to repair DNA double strand breaks and one of the well-described mechanisms is the loss of function of the BRCA1 or BRCA2 genes. Inhibition of the poly-ADP-ribose polymerase (PARP) is synthetic lethal with HR deficiency and the use of PARP inhibitors (PARPi) has significantly improved the outcome of patients with HGSOC with a greater benefit in patients with BRCA1/2 deficient tumors. However, intrinsic or acquired resistance to PARPi inevitably occurs in most HGSOC patients. Distinct heterogeneous mechanisms underlying the resistance to PARPi have been described, including a decrease in intracellular drug levels due to upregulation of multidrug efflux pumps, loss of expression/inactivating mutations in the PARP1 protein, restoration of HR and the protection of the replicative fork. Deciphering the molecular mechanisms of resistance to PARPi is of paramount importance towards the development of new treatment strategies and/or novel pharmacological agents to overcome this chemoresistance and optimize the treatment regimen for individual HGSOC patients. The current review summarizes the mechanisms underlying the resistance to PARPi, the available preclinical and clinical data on new combination treatment strategies (with chemotherapy, anti-angiogenic agents and immune checkpoint inhibitors) as well as agents under investigation which target the DNA damage response.


Subject(s)
Drug Resistance, Neoplasm/drug effects , Drug Resistance, Neoplasm/physiology , Ovarian Neoplasms/drug therapy , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Angiogenesis Inhibitors/administration & dosage , Angiogenesis Inhibitors/pharmacology , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/pharmacology , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/pharmacology , BRCA2 Protein/genetics , DNA Damage/drug effects , DNA Repair/physiology , Female , Humans , Immune Checkpoint Inhibitors/administration & dosage , Immune Checkpoint Inhibitors/pharmacology , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Poly(ADP-ribose) Polymerase Inhibitors/administration & dosage , Randomized Controlled Trials as Topic , Ubiquitin-Protein Ligases/genetics , Up-Regulation/physiology
5.
Neuropathol Appl Neurobiol ; 44(5): 449-462, 2018 08.
Article in English | MEDLINE | ID: mdl-28574618

ABSTRACT

AIMS: Pompe disease is an autosomal recessive lysosomal storage disorder resulting from deficiency of acid α-glucosidase (GAA) enzyme. Histopathological hallmarks in skeletal muscle tissue are fibre vacuolization and autophagy. Since 2006, enzyme replacement therapy (ERT) is the only approved treatment with human recombinant GAA alglucosidase alfa. We designed a study to examine ERT-related skeletal muscle changes in 18 modestly to moderately affected late onset Pompe disease (LOPD) patients along with the relationship between morphological/biochemical changes and clinical outcomes. Treatment duration was short-to-long term. METHODS: We examined muscle biopsies from 18 LOPD patients at both histopathological and biochemical level. All patients underwent two muscle biopsies, before and after ERT administration respectively. The study is partially retrospective because the first biopsies were taken before the study was designed, whereas the second biopsy was always performed after at least 6 months of ERT administration. RESULTS: After ERT, 15 out of 18 patients showed improved 6-min walking test (6MWT; P = 0.0007) and most of them achieved respiratory stabilization. Pretreatment muscle biopsies disclosed marked histopathological variability, ranging from an almost normal pattern to a severe vacuolar myopathy. After treatment, we detected morphological improvement in 15 patients and worsening in three patients. Post-ERT GAA enzymatic activity was mildly increased compared with pretreatment levels in all patients. Protein levels of the mature enzyme increased in 14 of the 18 patients (mean increase = +35%; P < 0.05). Additional studies demonstrated an improved autophagic flux after ERT in some patients. CONCLUSIONS: ERT positively modified skeletal muscle pathology as well as motor and respiratory outcomes in the majority of LOPD patients.


Subject(s)
Glycogen Storage Disease Type II/drug therapy , Glycogen Storage Disease Type II/pathology , Muscle, Skeletal/drug effects , Muscle, Skeletal/pathology , alpha-Glucosidases/therapeutic use , Adult , Aged , Enzyme Replacement Therapy/methods , Female , Humans , Male , Middle Aged , Recombinant Proteins/therapeutic use , Retrospective Studies
6.
Neurochem Res ; 41(1-2): 258-69, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26671766

ABSTRACT

Lipid composition of membranes is fundamental to modulate signaling pathways relying on lipid metabolites and/or membrane proteins, thus resulting in the regulation of important cell processes such as apoptosis. In this case, membrane remodeling is an early event important for the activation of signaling leading to cell death and removal of apoptotic cells. In the present study, we analyzed phospholipid, cholesterol and fatty acid content during apoptosis induced by manganese in PC12 cells. Lipid analysis of whole cells and detergent-resistant membranes was carried out by HPLC/GC. Results showed that apoptosis is associated with changes in lipid composition detectable in whole cell extracts, namely cholesterol, phosphatidylserine and phosphatidylethanolamine decreases. Noteworthy, phosphatidylserine level reduction was detectable before to the detection of apoptosis, in correlation with our previous study carried out by radioactive labelling. By contrast, phosphatidylserine and phosphatidylethanolamine changes were not detected in detergent resistant membranes, which instead showed an altered composition in phosphatidylinositol, phosphatidylcholine and sphingomyelin in apoptotic cells.


Subject(s)
Apoptosis/drug effects , Lipid Metabolism , Manganese/pharmacology , Animals , Chlorides/administration & dosage , Manganese Compounds/administration & dosage , PC12 Cells , Phospholipids/chemistry , Rats , Signal Transduction
7.
Neuromuscul Disord ; 25(5): 423-8, 2015 May.
Article in English | MEDLINE | ID: mdl-25728520

ABSTRACT

Adult Polyglucosan Body Disease (APBD) is a rare inherited leukodystrophy associated with axonal polyneuropathy, mainly reported in persons of Ashkenazi-Jewish descent. We describe three Italian siblings at disease onset, presenting in their fifties with a combination of pyramidal and ataxic signs, mild demyelinating neuropathy on neurophysiological investigation (1/3 cases) and transient symptoms (1/3). A leucoencephalopathy with infratentorial lesions without enhancement and medullary/spine atrophy was demonstrated on brain/spine MRI (3/3). Muscle biopsy was normal in 2/3; both muscle and nerve biopsy showed polyglucosan bodies in the sibling with polyneuropathy. This indicated a need for GBE1 sequencing, which revealed a novel missense mutation (c.1064G>A; p.Arg355His) and one previously described (c.1604A>G; p.Tyr535Cys) in all siblings. We highlight that peripheral neuropathy, deemed as disease hallmark, may be missing and that transient symptoms are confirmed as early disease manifestations. The pattern of damage at neuro-imaging described recurs irrespective of clinical presentation, constituting a unifying diagnostic clue.


Subject(s)
Glycogen Storage Disease/diagnosis , Nervous System Diseases/diagnosis , Family , Female , Glycogen Storage Disease/pathology , Glycogen Storage Disease/physiopathology , Humans , Italy , Male , Middle Aged , Muscle, Skeletal/innervation , Muscle, Skeletal/metabolism , Muscle, Skeletal/pathology , Myelin Sheath/pathology , Nervous System Diseases/pathology , Nervous System Diseases/physiopathology , Neural Conduction , Pedigree , Sural Nerve/metabolism , Sural Nerve/pathology , White People
8.
Cell Death Dis ; 5: e1019, 2014 Jan 23.
Article in English | MEDLINE | ID: mdl-24457963

ABSTRACT

Altered synaptic function is considered one of the first features of Alzheimer disease (AD). Currently, no treatment is available to prevent the dysfunction of excitatory synapses in AD. Identification of the key modulators of synaptopathy is of particular significance in the treatment of AD. We here characterized the pathways leading to synaptopathy in TgCRND8 mice and showed that c-Jun N-terminal kinase (JNK) is activated at the spine prior to the onset of cognitive impairment. The specific inhibition of JNK, with its specific inhibiting peptide D-JNKI1, prevented synaptic dysfunction in TgCRND8 mice. D-JNKI1 avoided both the loss of postsynaptic proteins and glutamate receptors from the postsynaptic density and the reduction in size of excitatory synapses, reverting their dysfunction. This set of data reveals that JNK is a key signaling pathway in AD synaptic injury and that its specific inhibition offers an innovative therapeutic strategy to prevent spine degeneration in AD.


Subject(s)
Alzheimer Disease/enzymology , JNK Mitogen-Activated Protein Kinases/metabolism , Synapses/enzymology , Alzheimer Disease/drug therapy , Alzheimer Disease/genetics , Animals , Disease Models, Animal , Female , Humans , JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , JNK Mitogen-Activated Protein Kinases/genetics , Male , Mice , Mice, Transgenic , Peptides/administration & dosage , Signal Transduction
9.
Neurol Res Int ; 2010: 808474, 2010.
Article in English | MEDLINE | ID: mdl-21188228

ABSTRACT

A 48-years old man was diagnosed an IgD-k multiple myeloma (MM) at age 38 years for which he successfully underwent chemotherapy and bone marrow transplant. He then developed a graft-versus-host disease (GVHD) whose manifestations included, three years later, a polymyositis, diagnosed at muscle biopsy and successfully treated with steroids. Few months after polymyositis remission, myeloma relapsed and the patient was treated with thalidomide for six years with good remission. Soon after thalidomide suspension, MM relapsed again and the patient came to our observation for a new onset of neuromuscular symptoms. He underwent both muscle and peripheral nerve biopsy to discriminate between myositis (paraproteinemia versus GVHD), amyloidosis, and thalidomide toxicity. The first muscle biopsy showed an inflammatory pattern with necrotic fibres, macrophagical invasion (CD68 positive), rare interstitial cellular infiltrates (CD8 positive and CD4 negative), widespread anti-HLA positivity and negative antiMAC. The second muscle biopsy showed the same inflammatory pattern plus an involvement of blood vessels. Direct immunofluorescence for IgD showed diffuse positivity along the sarcolemmal in both muscle biopsies. Sural nerve biopsy demonstrated both demyelinating and axonal aspects with no inflammatory infiltrates, but positivity for HLA and MAC. Congo Red was negative in both skeletal muscle and peripheral nerve.

10.
J Pharm Sci ; 98(11): 3961-86, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19338060

ABSTRACT

The aim of this review is to describe the theoretical background lying behind the solid drug mechanochemical activation by cogrinding pointing out its advantages and drawbacks. A brief historical introduction precedes the discussion about the mechanisms leading to solid drug activation. This allows to clarify the concept of solid activation whose main effect is to improve drug solubility and, thus, drug bioavailability. Then, the attention is focused on the experimental tools used to evaluate drug activation before the in vivo use. This, of course, permits to properly modulate the milling conditions (milling time, mill revolution speed, drug/carrier ratio and so on) in the light of the optimisation of milling process and activated system properties. Thereafter, the discussion shifts on the different kinds of mills that can be used and on mills classification based on the energy transferred to the materials. Fundamental tool to perform this task is the mathematical modelling of mill dynamics that is here shown for different mills kinds. Finally, some examples of activated systems performance both in vitro and in vivo are presented and discussed. In conclusion, mechanochemical activation improves drug bioavailability. Interestingly, this activation does not require the use of solvents whose elimination from the activated product can be difficult and expensive but a relatively simple mechanical treatment. On the other hand, this approach, usually, works only for poorly water soluble drugs (solubility <100 microg/mL) that do not exhibit permeability problems.


Subject(s)
Models, Theoretical , Pharmaceutical Preparations/chemistry , Biological Availability , Chemistry, Pharmaceutical , Dosage Forms , Drug Carriers , Pharmaceutical Preparations/administration & dosage , Pharmaceutical Preparations/classification , Solubility , Technology, Pharmaceutical
12.
Regul Toxicol Pharmacol ; 41(3): 228-39, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15748797

ABSTRACT

Hydrofluoropolyethers (HFPE) are a family of linear oligomeric fluorinated fluids comprising a chain of difluoromethoxy and tetrafluoroethoxy repeating units with terminal OCF2H end groups, each of which contains an isolated hydrogen atom. These fluids have been designed as low environmental impact substitutes for perfluorinated organic substances in a number of applications including heat transfer and fire suppression agents, and as a solvent. The toxicological profile of these new fluids has been evaluated and is presented in this paper. Acute toxicity tests have been performed on Sprague-Dawley Crl: CD (SD) BR rats using oral, dermal, and inhalation routes. No deaths were recorded even at the highest tested concentrations, and the resultant LD50/LC50 values were >5000 mg/kg (oral), >2000 mg/kg (dermal), and >26,411 ppm (inhalation: reversible anaesthetic effects, e.g., lethargy, seen at this exposure concentration). Other short-term tests (skin and eye irritation, skin sensitisation, genotoxicity tests in vitro and in vivo, cardiac sensitisation) were also performed, and no hazardous properties were identified. Effects of repeated exposure by inhalation were examined in rats over test periods of 5, 14, 28, and 90 days. Effects on embryo-foetal development in the rat have also been studied. The 28-day, 90-day and developmental studies were performed using nominal HFPE concentrations of 1000, 3300, and 10,000 ppm (6h/day: actual exposures confirmed by test atmosphere analysis), and the highest tested concentration proved to be an NOAEL in each study. Major observed effects were elevated urinary (inorganic) fluoride levels and increased liver weights with centrilobular hepatocyte hypertrophy (considered an adaptive response, linked to hepatic metabolism of absorbed material).


Subject(s)
Fluorine Compounds/toxicity , Liver/pathology , Polymers/toxicity , Animals , Embryonic Development , Ethers , Female , Fluorides/urine , Inhalation Exposure , Lethal Dose 50 , Male , No-Observed-Adverse-Effect Level , Rats , Rats, Sprague-Dawley , Risk Assessment
13.
J Phys Chem B ; 109(2): 711-5, 2005 Jan 20.
Article in English | MEDLINE | ID: mdl-16866431

ABSTRACT

In this paper the solid-state transformations under heating of cis-[Ir(CO)2Cl(C5H5N)] are discussed. The complexity of the transformations was revealed by integrating infrared spectroscopy, conventional and bidimensional X-ray diffraction, thermal analysis, and hot stage optical microscopy. During heating anisotropic expansion of the lattice along the Ir-Ir stacking takes place. Then cis-[Ir(CO)2Cl(C5H5N)] undergoes an irreversible solid-solid phase transition to a lattice of higher symmetry followed by a reversible transition into the amorphous phase. Under proper cooling a partial recrystallization takes place. Experiments in the presence of oxygen must be carried out in short time periods to avoid oxidation from Ir(I) to Ir(III).


Subject(s)
Iridium/chemistry , Optics and Photonics , Organometallic Compounds/chemistry , Temperature , Crystallization , Electrons
14.
Int J Pharm ; 254(2): 197-210, 2003 Mar 26.
Article in English | MEDLINE | ID: mdl-12623196

ABSTRACT

The aim of this work is to characterise the skin permeation properties of a male rat by means of a purely diffusive mathematical model based on Fick's second law. Additionally, in the attempt of proposing a reliable tool allowing the skin permeability (or resistance) determination on the basis of experimental data, the model automatically accounts also for two typical experimental conditions. In particular, drug dissolution in the donor environment and receiver sampling technique (part of the receiver volume is withdrawn and immediately replaced by fresh solvent) are considered. The results of this characterisation are then compared with those coming from a common simplified approach. Acyclovir is chosen as model drug and a thermostatic (37 degrees C) Franz cell apparatus is used to perform permeation experiments. This study suggests that Acyclovir permeation through the rat skin can be well described by the proposed model and that some differences arise in the evaluation of the full-skin resistance performed by means of our model or the usual simpler approach.


Subject(s)
Acyclovir/metabolism , Algorithms , Animals , Chromatography, High Pressure Liquid , Diffusion , In Vitro Techniques , Male , Models, Biological , Permeability , Rats , Skin Absorption , Solubility
15.
J Microencapsul ; 19(5): 603-14, 2002.
Article in English | MEDLINE | ID: mdl-12433303

ABSTRACT

The topic of this paper is the experimental and theoretical study of drug-release from a system of polydisperse microencapsulated particles that, for the sake of simplicity, are assumed to be spherical. The theoretical analysis performed yields of a mathematical model to describe the physical phenomena involved in drug-release from such a system. In particular, the model is based on the hypothesis of a progressive dissolution of the internal solid drug core (due to solvent penetration through the coating) that gives a liquid solution in the region between the coating and the dissolving solid core. The existence of a concentration gradient between the inner solution and the outer release environment determines drug diffusion through the coating. The coacervation technique was adopted to microencapsulate the solid drug cores (theophylline, a bronchodilator for the treatment of chronic asthma and chronic obstructive lung disease) by an insoluble polymeric layer of ethylcellulose. The amount of drug released from these microencapsulated particles to the external receiver phase is monitored by means of a UV spectrophotometer. As the proposed model fits the experimental results well, it was concluded that it can be a good tool to design and to study this kind of drug-release system.


Subject(s)
Capsules/chemistry , Delayed-Action Preparations/chemistry , Bronchodilator Agents/administration & dosage , Bronchodilator Agents/pharmacokinetics , Drug Compounding , Humans , In Vitro Techniques , Microscopy, Electron, Scanning , Models, Theoretical , Particle Size , Theophylline/administration & dosage , Theophylline/pharmacokinetics
16.
Eur J Cancer Prev ; 11(2): 193-7, 2002 Apr.
Article in English | MEDLINE | ID: mdl-11984139

ABSTRACT

Sphingolipids are widespread membrane components that are found in all eukaryotic cells. They consist of a long chain sphingoid-base, usually sphingosine, which is acylated at the 2-amino position, forming a ceramide. All together, sphingolipids may represent the most structurally diverse category of lipids in nature. There is no known nutritional requirement for sphingolipids. Nonetheless, studies with experimental animals have shown that consumption of sphingolipids inhibits colon carcinogenesis, reduces serum low-density lipoprotein cholesterol and elevates high-density lipoproteins, which suggest that they are 'functional' components of food. In animal models (CF1 mice) sphingomyelin supplementation reduces the number of aberrant colonic crypt foci by approximately 70% and, with longer feeding, reduces the number of colonic adenocarcinomas. A possible mechanism of action of sphingolipids in suppressing colon carcinogenesis is that exogenously supplied sphingolipids bypass a sphingolipid signalling defect that is important in cancer (for example, a loss of cellular sphingomyelin turnover to produce ceramide and sphingosine). Indirect evidence suggests that sphingolipids can inhibit colon cancer in humans: sphingosine and ceramide induce apoptosis in a human adenocarcinoma cell line and feeding sphingolipids to Min mice reduces the number of colon tumours.


Subject(s)
Adenocarcinoma/prevention & control , Colorectal Neoplasms/prevention & control , Dietary Fats/administration & dosage , Sphingolipids/administration & dosage , Animals , Cheese/analysis , Forecasting , Milk/chemistry , Signal Transduction , Sphingolipids/analysis
17.
J Control Release ; 76(1-2): 93-105, 2001 Sep 11.
Article in English | MEDLINE | ID: mdl-11532316

ABSTRACT

In this paper attention is focused on the determination of the drug diffusion coefficient in a swollen polymeric membrane referring to a recent mathematical model (linear model). The main advantage deriving from its use is that, despite its analytical nature and its ability to account for the most important aspects characterising a permeation experiment, it can also be applied in the case of thick membranes. To check the model reliability, a comparison is made with a more complex numerical model and with a largely employed model in terms of data fitting quality. To this purpose, particular care is devoted to the experimental and theoretical tools employed to calculate the auxiliary parameters required by the three models, and with the aim of getting a drug diffusion coefficient value as accurate as possible. Theophylline was chosen as model drug owing to its wide employment in the pharmaceutical field. Membranes were prepared with sodium alginates hydrogels at three different polymer concentrations. The present analysis demonstrates the reliability of the linear model and reveals that the theophylline diffusion coefficient is not significantly affected by the polymer concentration. Indeed, such a parameter is reflected in different membrane thicknesses rather than in different mesh sizes of the polymeric network.


Subject(s)
Alginates/administration & dosage , Theophylline/chemistry , Diffusion , Glucuronic Acid , Hexuronic Acids , Mathematics , Models, Theoretical , Theophylline/administration & dosage
18.
Cancer Detect Prev ; 24(3): 207-11, 2000.
Article in English | MEDLINE | ID: mdl-10975281

ABSTRACT

The aim of this study was to analyze possible changes in the total phospholipid distribution in murine mammary adenocarcinomas induced in transgenic mice by the tissue-specific expression of the neu oncogene, as compared with normal tissues. To understand whether the altered phospholipid profile might be specifically tissue-related to the oncogene expression, phospholipid composition also has been analyzed in liver, kidney, lung, and spleen. The data indicate that only tumor mammary tissues show a drastic increase of the total phospholipid content (P < 0.0001) associated with a significant increment of phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin (P < 0.05). Moreover, gas-chromatography analysis of total phospholipid-derived fatty acids shows a decrease in the percentage content of linoleic acid in tumor tissues, suggesting an altered metabolism of this fatty acid related to the enhanced epithelial proliferation. We conclude that neu transgenic mice provide a good model to clarify the involvement of phospholipids in neu-induced neoplastic transformation and to study in vivo the metabolic pathways related to the intracellular signaling.


Subject(s)
Adenocarcinoma/metabolism , Mammary Neoplasms, Animal/metabolism , Phospholipids/biosynthesis , Receptor, ErbB-2/metabolism , Animals , Cell Division , Chromatography, Gas , Fatty Acids/metabolism , Female , Kidney/metabolism , Linoleic Acid/metabolism , Liver/metabolism , Lung/metabolism , Male , Mice , Mice, Transgenic , Phosphatidylcholines/metabolism , Phosphatidylethanolamines/metabolism , Receptor, ErbB-2/genetics , Signal Transduction , Sphingomyelins/metabolism , Spleen/metabolism
19.
Biochim Biophys Acta ; 1485(2-3): 214-24, 2000 May 31.
Article in English | MEDLINE | ID: mdl-10832101

ABSTRACT

Glycosphingolipids are plasma membrane macromolecules involved in diversified recognition functions on the cell surface resulting in modulation of cell adhesion and differentiation. As the in vitro cellular system of the neoplastic cell line SGS/4A and syngeneic normal fibroblasts (FG) represents a useful tool for studies on molecular mechanisms regulating cell adhesion, neoplastic transformation and cellular ageing, we studied the changes of glycosphingolipid and of the enzymes involved in their metabolism in both cultured cells at different subculture stages. The FG subculture progression induces a drastic decrease of total glycosphingolipid content with consistent alterations in the molecular composition. In particular, a significant decrease of GM(3), a slight increase of GD(1a), the disappearance of 'b'-series gangliosides and the drastic reduction of triosylceramides were observed. On the contrary, the increasing number of SGS/4A subcultures, characterized by a specific and different glycosphingolipid composition as compared with FG cells, does not cause modifications. Although glycosyltransferase activity levels quite well parallel the glycosphingolipid patterns and can account for the noted variations, the mRNA expression analysis of two glycosyltransferases suggests that the in vitro cell ageing of normal rat fibroblasts causes drastic changes in the glycosphingolipid profile through the regulation, at either the transcriptional or post-translational level, of some biosynthetic enzymes.


Subject(s)
Fibroblasts/metabolism , Glycosphingolipids/metabolism , Animals , Cells, Cultured , Fibroblasts/cytology , Gangliosides/metabolism , Gene Expression , Glycosphingolipids/biosynthesis , N-Acetylgalactosaminyltransferases/genetics , N-Acetylgalactosaminyltransferases/metabolism , Neutral Glycosphingolipids/metabolism , RNA, Messenger , Rats , Sialyltransferases/genetics , Sialyltransferases/metabolism , Tumor Cells, Cultured , Polypeptide N-acetylgalactosaminyltransferase
20.
J Control Release ; 59(3): 343-59, 1999 Jun 02.
Article in English | MEDLINE | ID: mdl-10332065

ABSTRACT

This work proposes two different mathematical models (linear and numerical) able to simulate the drug permeation through a swollen membrane sandwiched by two external layers (trilaminate system). Moreover, a solid drug dissolution phenomenon in the donor compartment may be accounted for. Indeed, this is a situation that may often occur in permeation experiments. An insufficient stirring of the donor and of the receiver volume may give rise to two sandwiching layers and the target of a constant drug concentration in the donor compartment may be accomplished by putting a solid drug amount in the saturated donor solution. The linear model shows the advantage of having an analytical expression which extremely simplifies the calculation of the drug diffusion coefficient D inside the membrane. Its main drawback lies in the fact that it works only for thin trilaminate systems. The numerical model is more general than the linear one, as it works for all kind of trilaminate thickness and it may account for a solid powder dissolution in the donor compartment. Of course, it does not have an analytical solution and, thus, the D determination is less easy to perform as the numerical model is more time consuming than the linear one. These two models are then compared with the classical approach developed by Flynn and Barrie in order to better define its validity limits.


Subject(s)
Membranes, Artificial , Models, Theoretical , Pharmacokinetics , Diffusion , Linear Models , Reproducibility of Results , Solubility
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