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Biomedical subjects

F Castelli

Publications and source records attributed to F Castelli.

At least 37 records · Page 2Linked to original sources
PubMed2000

Influence of different parameters on drug release from hydrogel systems to a biomembrane model. Evaluation by differential scanning calorimetry technique.

A comparative study on the drug release capacity of four water swellable polymeric systems was carried out by differential scanning calorimetry (DSC). The polymeric systems chosen were alpha,beta-polyaspartahydrazide (PAHy) crosslinked by glutaraldehyde (GLU) (PAHy-GLU) or by ethyleneglycoldiglycidylether (EGDGE), (PAHy-EGDGE), polyvinylalcohol (PVA) crosslinked by glutaraldehyde (PVA-GLU) and alpha,beta-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) by gamma irradiation (PHEA-gamma matrices). The degree of crosslinking for PAHy-GLU, PAHy-EGDGE and PVA-GLU samples was about 0.4 and 0.8. These hydrogels were characterized as free of drugs and were loaded with diflunisal (DFN) (approximately 2.5% w/w). Diflunisal, a non-steroidal anti-inflammatory drug, has been chosen as a model drug to be incorporated into polymeric matrices to follow the release processes of a drug from these hydrogels to a model membrane made by unilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC). Differential scanning calorimetry appears to be a suitable technique to follow the transfer kinetics of the drug from the controlled release system to the biomembrane model. The drug releases from all the considered polymeric hydrogels, were compared with the release observed from the drug solid form by examining the effects on the thermotropic behaviour of DPPC unilamellar vesicles. The release kinetics of the drug from hydrogels were followed at 25, 37 and 50 degrees C to evidence the influence of temperature on the drug release and on the successive transfer to biological membrane model. Particularly, it appears evident that the total amount of drug transferred and the release rate are affected by the polymer crosslinking degree (it increases with crosslinking decrease) as well as by the nature of crosslinking agent. In fact, the drug release profiles from PAHy-GLU samples are more differentiated than those from PAHy-EGDGE. The effect of parameters correlating with the properties of starting polymer, such as water-affinity, crystallinity, glass-to-rubber transition temperature and affinity towards drug molecules, has been also evaluated.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2000

Quantification of the impact of HIV-1 reverse transcriptase and protease mutations on the efficacy of rescue HAART.

The reduction in the efficacy of rescue treatment (administered on a clinical basis) due to drug resistance was retrospectively quantified in 55 human immunodeficiency virus type 1 (HIV-1)-infected patients failing highly active antiretroviral therapy (HAART) by using a novel score calculation system based upon HIV-1 reverse transcriptase (RT) and protease (PR) mutations. Patients were all naive for nelfinavir (NFV) and efavirenz (EFV) and were assigned to one of the following rescue therapy schedules: (i) 17 patients received NFV + EFV + stavudine (d4T) (group A); (ii) 14 patients received NFV + saquinavir (SQV) + lamivudine (3TC) + d4T/zidovudine (AZT) (group B); (iii) 19 patients received NFV + d4T + didanosine (ddI)/3TC/zalcitabine (ddC) (group C); (iv) five patients received miscellaneous treatments including NFV (group D). Responders were considered patients showing a drop in HIV-1 RNA level > 0.5 log10 after 3 months of therapy. Forty-eight (28 responders and 20 non-responders) out of 55 patients completed the first 3 months of rescue therapy and reduction in HIV-1 viral load was found to be significantly higher in group A compared to groups B and C (81.2% responders vs. 38.5 and 40.0%, respectively). At baseline, no patient carried EFV- or d4T-resistant HIV-1 strains, despite prolonged administration of d4T, while 41/48 (87.2%) patients had mutations conferring resistance to NFV in the absence of previous treatment with this drug. A significant inverse correlation between reduction in viral load and reduction in therapy efficacy due to drug resistance, as determined by the score calculation system, was found (r = 0.62). A cut-off value of 36% reduction in therapy efficacy showed a positive predictive value (capacity to detect failure of rescue treatment) of 81.2% and a negative predictive value (ability to detect successful treatment) of 75.8%. In addition, 45 out of 48 patients completed also the 9-12 month period of rescue therapy and 10/28 responders had a rebound in HIV-1 viral load level detected after the first 3 months of rescue therapy. Of these, 5/7 (71.4%) showed a further reduction in rescue therapy efficacy due to the emergence of new mutations.

Anti-HIV Agents↗
PubMed2000

Calorimetric evidence of differentiated transport of limonin and nomilin through biomembranes.

The effect exerted by two structurally similar limonoids possessing antifeedant and anticancer activity, limonin and nomilin, on the thermotropic behavior of model membranes constituted by dimyristoylphosphatidylcholine (DMPC) vesicles was studied by differential scanning calorimetry. Attention was directed to evaluate modifications in phytochemical-lipid interaction induced by compound structure and lipophilicity and to evidence their different membrane penetration. The two examined compounds, when dispersed in liposomes during their preparation, were found to exert a very different action on the L(beta)-L(alpha) gel-to-liquid crystal phase transition of DMPC multilamellar vesicles. Nomilin caused a detectable effect on the transition temperature (T(m)), shifting it toward lower values with a concomitant small decrease of the associated enthalpy (DeltaH) changes, while limonin was not able to modify the lipid vesicles thermotropic behavior. Modifications induced by nomilin were a function of phytochemical concentration, while the different behavior of limonin can be due to the different polarity induced by the presence of the single A ring in nomilin that possesses an acetyl group versus the A,A' ring system of limonin. Solid limonoids and aqueous dispersions of multilamellar (MLVs) or unilamellar vesicles (LUVs) (limonoids molar fraction 0. 045, 0.12, and 0.18) were left in touch for long incubation times at temperatures higher than T(m) to detect their spontaneous transfer through the medium. By following this procedure, no interaction was detected for limonin with lipid vesicles. The rate of transfer and interaction of nomilin was a function of the kind of vesicle species (faster for LUV, slower for MLV). The interaction, monitored by compound transfer from the solid phytochemical to the lipidic species after several periods of incubation, was on the same order as that detected by preparation carried out in organic solvent. The obtained results can be explained in terms of compound hydrophobicity, and a relation between compound structure and membrane interaction can be suggested. This allows the membrane interaction with nomilin, but the low water solubility of limonin hinders or totally blocks its transfer through the aqueous medium.

Benzopyrans↗
PubMed2000

Prevalence and distribution of soil-transmitted helminth (STH) infections in urban and indigenous schoolchildren in Ortigueira, State of Paranà, Brasil: implications for control.

Soil-transmitted helminth (STH) infections represent a major public health problem in poor and developing countries. During the period September-October 1998 we conducted an epidemiological survey of STH infections in schoolchildren of an urban area (group A) and an indigenous reserve (group B), in the Municipality of Ortigueira, State of Paranà, Brazil, to assess potential benefits of mass treatment. Stool samples were examined for helminth eggs by quantitative (Kato-Katz) technique to determine the prevalence and intensity of intestinal parasitic infection. Moreover, we examined the relationship between prevalence and intensity of STH infections and housing/hygienic factors (by means of a 7-item questionnaire). 236 schoolchildren aged 5-15 years were enrolled, 136 in group A and 100 in group B. The prevalence of STH infections was significantly higher in group B (93%) than in group A (22%) (P < 0.001). Detected parasites were: A. lumbricoides (16.1% prevalence in group A, 88% in group B, P < 0.001), hookworms (5.8% in group A, 52% in group B, P < 0.001) and T. trichiura (5.1% in group A, 2% in group B, P = 0.2). Heavy infections were detected in 2.9% and 23% of the children in group A and B, respectively (P < 0.001). Housing/hygienic indicators were significantly poorer in group B. A statistically significant correlation was observed between total prevalence of STH infections and prevalence of high-intensity infections with most housing/hygienic variables. On the basis of these results, mass treatment and educational interventions were suggested for the indigenous community, whereas target treatment and educational interventions were suggested for the urban community. Even in a geographically homogeneous area different epidemiological realities can be found, which in turn can influence infection levels and control programmes.

Adolescent↗
PubMed1999

Molecular mechanisms of photosensitization XIII: a combined differential scanning calorimetry and DNA photosensitization study in non steroidal antiinflammatory drugs-DNA interaction.

A combined differential scanning calorimetry (DSC) and photosensitization study has been carried out on the interaction of several NSAID on DNA, both from calf thymus and pBR 322 plasmid. The investigated compounds were both non-steroidal anti-inflammatory drugs as well as compounds related to NSAIDs for structural similar properties, to find evidence for their ability to interact with DNA as a function of steric hindrance and polarity of the chemical structures. The considered NSAIDs were diflunisal (DFN, a salicylic derivative), naproxen (NAP), ketoprofen (KPF), suprofen (SPF) and tiaprofenic acid (TIA, arylpropionic acids). The structural criterion used was related to three different aromatic groups, biphenyl, naphthalene and benzophenone (BZP). In fact drug-DNA interaction can be revealed by variations of the enthalpies and temperatures of unfolding of DNA obtained by comparison of calorimetric peaks, where a decrease of the enthalpy is associated with the drug-DNA interaction, by engaging electrostatic bonds. Testing their ability in inducing DNA cleavage when UVA irradiated can evidence the photosensitizing properties of the drug. A good correlation was found between calorimetric and photosensitization studies. From the results obtained it can be reasonably supposed that the photocleavage depends only on the drug molecules bound to DNA.

Animals↗
PubMed1999

Influence of maternal CD4 levels on the predictive value of virus load over mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1). Study Group for Vertical Transmission.

Forty-four anti-HIV seropositive pregnant women were enrolled in a study of maternal factors related to mother-to-infant human immunodeficiency virus type 1 (HIV-1) transmission. HIV-1 infection was documented in 11 of 45 infants (24.4%). Obstetric factors, maternal CD4 counts, and disease stage were not related to the risk of transmission. HIV-1 RNA levels at delivery were significantly higher in mothers who transmitted the infection (P = .024). A strong relationship between viral load and risk of transmission was observed in women with stage A1 (P= .006), but not in those with stages A2-A3. These results suggest that vertical transmission of HIV-1 is multifactorial and that viral load plays a major role in mothers with early-stage HIV-1 infection.

Adult↗
PubMed1999

Differences between coumaric and cinnamic acids in membrane permeation as evidenced by time-dependent calorimetry.

We carried out an investigation by differential scanning calorimetry (DSC) on the effect of two structurally similar bioactive plant phenols, cinnamic and p-coumaric acids, on the phase transition of model membranes constituted by dimyristoylphosphatidylcholine (DMPC) vesicles. The aim was to evaluate how pH and molecular substituents influence liposolubility and thereby modify vesicle permeability. A change in permeability would result in modifications to the phase transition for DMPC liposomes such that the transition temperature would be lowered and the enthalpy changes should be little affected. Evidence of differences in permeability was obtained by comparing the effects exerted by the two compounds left in touch with unilamellar and multilamellar vesicles, at two different pHs (4 and 7.4). While the p-coumaric acid was unable to appreciably modify the thermotropic behavior of the model membrane, the cinnamic acid interacted with lipid vesicles at both pH's, even if at acidic pH the effect was greater than neutral. It can be hypothesized that the interaction between the cinnamic acid and the lipidic layers is due to the lack of a hydroxyl group. This interaction is enhanced by an acidic pH, where the carboxylic acid is in a protonated form.

Calorimetry, Differential Scanning↗
PubMed1999

Serum IgG antibodies to human herpesvirus-6 (HHV-6) do not predict the progression of HIV disease to AIDS. Italian Seroconversion Study group.

OBJECTIVES: To evaluate if different levels of human herpesvirus 6 (HHV-6) antibodies can predict HIV disease progression. DESIGN: Longitudinal study of individuals with a documented date of HIV seroconversion. SETTING: Clinical centers located throughout Italy. PATIENTS: Individuals who serconverted for HIV between 1983 and 1995 in Italy. METHODS: Sera were tested for IgG antibodies to HHV-6 using a commercial enzyme immunoassay. A serum sample with an optical density (OD) > or =242 (i.e. the mean value of 10 negative controls +4x standard deviation) was considered as HHV-6 positive; the progression of HIV disease was evaluated estimating the relative hazards (RH) of AIDS (by Cox models) for individuals with higher levels vs. lower levels of HHV-6 antibodies or considering levels of antibodies based on 10% increase of the distribution (deciles). Rates of CD4 decline fitting linear regression were also estimated. RESULTS: A total of 381 persons were followed for a median time of 4 years (range: 0.15-9 years) following the date of collection of the serum sample. The median OD value of HHV-6 antibodies was 306, with an interquartile range of 241-440 and a range of 48-2330. A slight inverse correlation was found between HHV-6 antibody levels and age of the individual at the time of serum collection (Spearman rank correlation coefficient, -0.16; p = 0.0013). No association was found between HHV-6 and CD4 level or between HHV-6 and CD8 level at the date of serum collection. The unadjusted RH of progression to AIDS was 0.63 (95% CI: 0.42-0.96) for HHV-6 positive individuals vs. HHV-6 negative; when adjusting for possible confounders (CD4, age, pre-AIDS HIV-related pathologies at the date of sera collection, and previous anti-herpes treatment), the RH of AIDS increased to 0.80 (95% CI: 0.51-1.23). No particular association with HIV disease progression was found when using the deciles of the distribution of HHV-6 antibodies. The median CD4 cell loss was 5.0x10(6) cells/l per month among HHV-6 positive individuals and 5.7x10(6) cells/l per month among the others. CONCLUSIONS: The presence of high levels of HHV-6 antibodies does not seem to predict the clinical or immunologic progression of HIV disease.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Pharmacokinetics of efavirenz (EFV) alone and in combination therapy with nelfinavir (NFV) in HIV-1 infected patients.

AIMS: To define the pharmacokinetic profile of efavirenz (EFV) in HIV-1 infected patients, when administered alone or with nelfinavir (NFV). METHODS: Eleven HIV-positive patients, in steady-state treatment with EFV and 11 patients in steady-state treatment with EFV+NFV, were evaluated. Blood samples for pharmacokinetic analysis were obtained during a dosage interval. Plasma concentrations of EFV were determined by h.p.l.c. RESULTS: No significant difference was found between the principal pharmacokinetic parameters of EFV when administered alone or in combination with NFV (mean AUC: 57.1-7727.3 vs 60.9+/-12.3 microg ml-1 h; mean CL/F: 0.18+/-0.072 vs 0.16+/-0.04 l h-1 kg-1; mean Cmax: 4.0+/-1.7 vs 4.3+/-1.2 microg ml-1, and mean tmax: 4.1+/-1.7 vs 3.5+/-0.5 h) Mean trough plasma concentrations (C0) of EFV were 1.64+/-0.93 microg ml-1, with and without NFV. A good correlation was found between C0 and AUC(0,24h) (r=0.96; P<0. 01). CONCLUSIONS: Despite the common metabolic pathway, there was no significant influence of NFV on the pharmacokinetics of EFV. EFV exhibits a relatively low interindividual variability and a dosing regimen of 600 mg day-1 assures plasma concentrations that are adequate for inhibition of viral replication.

Adult↗
PubMed1999

Epidemiological features and case management practices of imported malaria in northern Italy 1991-1995.

We report the results of a retrospective analysis of the clinical charts of imported malaria cases notified during the period 1991-95 in the Lombardy region of northern Italy. We analysed 694 admissions related to 683 individuals. The proportion of immigrants increased during the observation period from 34.4% in 1991 to 59.9% in 1995 (P = 0.002). P. falciparum was the causative species in 534 cases (78. 2%), and 591 (90.1%) of 656 cases with a full travel history had travelled to Africa. Information on chemoprophylaxis was available in 604 cases: 429 (71.0%) reported no drug intake, 140 (23.2%) an incomplete, and 35 (5.8%) a complete chemoprophylactic course. The proportion of subjects who had initiated malaria chemoprophylaxis was significantly lower among immigrants (7.4%) than nonimmigrants (50.2%) (P < 0.001). Severe disease was diagnosed in 26 (4.7%) of 551 cases of falciparum malaria, with a significantly lower incidence among immigrants (1.3% vs. 9.2%; P < 0.001). Eight deaths were recorded, all among nonimmigrants, whose fatality rate was significantly higher (P = 0.02). Mefloquine treatment of cases of uncomplicated falciparum malaria was associated with a significantly shorter fever clearance time (2.8 days +/- 1.5 vs. 3.5 days +/- 1.9; P < 0.001) and mean hospital stay (5.9 days +/- 4.4 vs. 8.3 days +/- 5.1; P < 0.001) compared to quinine treatment.

Adult↗
PubMed1999

Pediatric migration and hepatitis A risk in host population.

Hepatitis A virus (HAV) circulation in a given area is closely related to socioeconomic standards. Following the improvement of living conditions, HAV seroprevalence rates in the population have decreased steadily during the last decades in many Western European countries, including Italy, thereby leading to a shift of risk of disease towards older age groups. Since the severity of the disease closely parallels age, a higher incidence of symptomatic cases in adults is now reported in Europe and the United States, being travel-related to a large extent. Intrafamilial person-to-person spread is also an important source of infection and transmission from children to parents may occur due to the lack of immunity in the general population. In the last two decades, Italy has been the destination of an increasing number of migrants from developing countries, where HAV is highly endemic. Furthermore, international adoption programmes cause pediatric populations from HAV endemic countries to increase in low endemic areas, possibly leading to secondary cases in close contacts.7 The aim of this paper is to report the epidemic HAV outbreak which occurred among the voluntary nursing staff of a pediatric Rwandan refugee community hosted in a village of the Brescia Province, in northern Italy.

Adult↗
PubMed1999

Malaria in migrants.

An increasing proportion of malaria cases in Italy is observed in immigrants revisiting their country of origin, but little specific research work has been carried out in this field. All malaria cases occurring from 1990 to 1998 at the Reference Clinic for Infectious and Tropical Diseases in Brescia were prospectically evaluated to compare clinical outcome in migrant and non-immune cases. No difference was observed between parasitaemia at diagnosis and time to clearance of peripheral parasitaemia. Clinical presentation was milder in migrants than in non-immunes, with an OR for severe malaria of 0.27 (c.i. = 0.09-0.84) (p = 0.01). Fever clearance time was significantly shorter in migrants (3.0 days, SD = 1.2) than in non-immunes (4.3 days, SD = 1.7) (p < 0.001). Among immigrants, the proportion of severe cases was higher in residents since 2 years or less (12.5%) compared to residents since 2 to 5 years (3.3%) and residents since more than 5 years (0.9%) (p = 0.02). The proportion of malaria cases who had used chemoprophylaxis was significantly lower among immigrants (30/272, 11.0%) compared to non-immunes (41/74, 55.4%) (p < 0.001). In a population based malaria KAP analysis among 504 migrants from malaria endemic countries, correct knowledge of malaria risk was reported by 351 (69.5%). Of 170 subjects who reported at least one visit back to the home country, 30 (17.6%) had sought pre-travel advice, 24 (14.1%) had started chemoprophylaxis and 7 (4.1%) had completed it during the last visit. Of 140 migrants who failed to seek pre-travel advice, 73 (52%) were unaware of malaria risk, 56 (40%) did not know how to protect themselves, and 11 (8%) refused to use protective measures. Migrants account for a significant proportion of imported malaria cases in industrialised countries. Clinical presentation is milder compared to non-immune subjects. The proportion of migrants who adopt malaria protective measure while returning home is very low, due to both unawareness of risk and inappropriateness of medical advice.

Adult↗
PubMed1998

[Principles and management of the ambulatory treatment of traveller's diarrhea].

Traveller's Diarrhea (TD, turista) is the most common health disturbance in travellers, affecting 20-50% of two-week travellers depending on their origin, destination and eating habits. The etiological agents most frequently isolated from the stools are enterotoxinogenic Escherichia coli (ETEC), Salmonella spp., Shigella spp., but the rate of isolation of Campylobacter spp. and non cholera vibrios is also high in Asia. Preventive measures in eating habits should in principle be able to curb the incidence of TD but compliance of travellers is usually poor. Antibiotic chemoprophylaxis has proved effective, but economic, safety and microbiological (drug resistance) considerations discourage its widespread use. Any treatment strategy should consider that TD is usually a self-limiting, benign illness in most travellers, even though infants, elderly people or persons with severe baseline diseases (heart diseases, diabetes, immunocompromised hosts, etc...) may sometimes suffer severe consequences. Adequate rehydration is the cornerstone of treatment and intestinal motility inhibitors may be used in adults (not in children) with severe diarrhea during the first 24 hours if the suspicion of invasive pathogen has been ruled out. Routine antibiotic treatment of TD is controversial, due to the benign nature of the syndrome and to the impossibility to ascertain its causative agent. It should be limited to severe and disabling cases. Among the many antibiotics tested, quinolones are now considered first-choice treatment worldwide, even though disturbing reports of the increasing prevalence of quinolone-resistant Campylobacter spp. from Asia have been recently published. Cotrimoxazole is efficient in Central America. The role of non absorbed antibiotics and probiotics is still to be fully elucidated.

4-Quinolones↗
PubMed1997

Study of spontaneous apoptosis in HIV+ patients: correlation with clinical progression and T cell loss.

In vitro spontaneous apoptosis (SA) of lymphocytes was studied in HIV infection to evaluate possible clinical and prognostic correlations, in a transsectional study of 101 individuals in different clinical categories and in a prospective longitudinal study of 18 asymptomatic individuals (mean follow-up, 17.2 months). The rate of SA was higher in HIV+ patients than in healthy controls (p < 0.001) and was higher in patients with AIDS than in the other HIV+ individuals (p < 0.001). It was inversely correlated with the peripheral blood CD4+ (R -0.61; p < 0.001) and CD8+ (R -0.46; p < 0.001) cell numbers. In a group of long-term survivors (LTS), it was significantly lower than in a control group of asymptomatic HIV+ patients with a similar number of circulating CD4+ lymphocytes but a shorter follow-up (p < 0.02). In the five asymptomatic HIV-infected individuals who showed a clinical progression, peaks of SA rates above the normal range before the clinical event were much more frequent than in those who remained asymptomatic (p < 0.0001), even though they were fairly homogeneous as far as CD4+ cell count and viral load were concerned. The median levels of SA rates were moreover correlated with the rate of total T cell loss (R -0.46; p 0.053). This study suggests that evaluation of the SA levels may provide a predictive factor for clinical and immunological progression of HIV-related immunodeficiencies and strengthen the hypothesis for the role of this phenomenon in the pathogenesis of this progression.

Adult↗
PubMed1997

Comparison of pharmacokinetics and dynamics of two dosage regimens of foscarnet in AIDS patients with Cytomegalovirus retinitis.

OBJECTIVE: To compare the pharmacokinetics of foscarnet administered as an infusion twice daily (BID) or thrice daily (TID), and to compare the effects on the electrolyte balance, cardiac and renal functions over a 3-week induction treatment of Cytomegalovirus (CMV) retinitis. METHODS: Pharmacokinetics/dynamics of foscarnet were investigated on treatment days 1, 14 and 21. Twelve AIDS patients with CMV retinitis completed the investigation period. Concentrations of foscarnet and electrolytes were assayed by high-performance liquid chromatography (HPLC) and by an ion-selective analyser, respectively. RESULTS: The pharmacokinetics of the two regimens were essentially similar. Foscarnet plasma and creatinine clearances were 2.0 and 1.6 ml.min-1.kg-1, respectively, in the BID group at steady state (day 21). In the TID group the corresponding values were 1.8 and 1.7 ml.min-1.kg-1, respectively. In both regimens the elimination half-life of foscarnet was 2-3 h. Ionized calcium concentrations were transiently decreased and strongly inversely correlated to foscarnet plasma concentrations in both regimens with no significant differences between groups. A trend towards prolongation of the QTc interval was seen when data from both treatments were analysed together. CONCLUSION: Our data suggest comparable pharmacokinetics of foscarnet after intermittent administration BID or TID during a 3-week induction period.

AIDS-Related Opportunistic Infections↗
PubMed1997

Plasmodium falciparum: an electronmicroscopy study of caveolae and trafficking between the parasite and the extracellular medium.

Caveolae containing grape-like tubulovesicular structures were observed in the cytoplasm and in the parasitophorous vacuole of ring- and trophozoite-stage Plasmodium falciparum parasites. In appliqué-forms intact caveolae and free vesicles were also seen to bud off the surface of infected erythrocytes directly from the parasitophorous vacuole where the parasite was in close vicinity to the host cell membrane. The mean vesicle diameter was 0.08-0.1 micron. No such structure was observed in schizonts, segmenters or in the cytoplasm of infected or uninfected erythrocytes. These structures may represent morphological evidence in P. falciparum of a "window" through which the parasite would have direct access to the extracellular milieu. They may constitute carrier vesicles containing parasite membrane transport molecules possibly involved in malaria pathogenesis and/or immunity.

Animals↗
PubMed1997

Dipalmitoylphosphatidylcholine/linoleic acid mixed unilamellar vesicles as model membranes for studies on novel free-radical scavengers.

Large unilamellar vesicles (LUVs) are generally accepted to be a suitable model for peroxidation studies. In the present report, dipalmitoylphosphatidylcholine (DPPC)/linoleic acid-mixed LUVs were employed as model membranes to verify the inhibitory effect of tocopherol (an efficient representative antioxidant) against 2,2'-azobis(2-amidinopropane)hydrochloride-induced peroxidation (evaluated by monitoring conjugated diene accumulation). In this model, the appropriate experimental conditions (particularly, liposome composition and peroxidation temperature) were selected following characterization of bilayer physical state, and not only by evaluation of peroxidation rate. Thus, the experiments described provide a routine screening procedure that would be appropriate for assessing the activity profile of novel free-radical scavengers.

1,2-Dipalmitoylphosphatidylcholine↗