Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 108
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Soft Matter ; 20(4): 923-939, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38189452

RESUMO

We present a comprehensive numerical study of the phase behavior and dynamics of a three-dimensional active dumbbell system with attractive interactions. We demonstrate that attraction is essential for the system to exhibit nontrivial phases. We construct a detailed phase diagram by exploring the effects of the system's activity, density, and attraction strength. We identify several distinct phases, including a disordered, a gel, and a completely phase-separated phase. Additionally, we discover a novel dynamical phase, that we name percolating network, which is characterized by the presence of a spanning network of connected dumbbells. In the phase-separated phase we characterize numerically and describe analytically the helical motion of the dense cluster.

2.
J Dairy Sci ; 107(9): 6758-6770, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38670336

RESUMO

Researchers have reported the benefits of feeding rumen-protected methionine (RPM) during the peripartum on the health parameters of dairy cows. Rumen-protected Met has reportedly improved milk yield, milk components, and liver health, but the literature is scarce on its effects in commercial herds. Therefore, we aimed to determine the effects of feeding RPM (Smartamine M, Adisseo Inc., Antony, France) prepartum (8 g/cow per day) and postpartum (15 g/cow per day) on performance, metabolic profile, and culling rate of Holstein cows in a commercial herd. One hundred sixty-six (n = 166) Holstein cows, 58 nulliparous and 108 parous, were randomly assigned to 1 of 2 dietary treatments, consisting of TMR top-dressed with RPM (RPMet; 2.35% and 2.24% Met of MP for close-up and fresh cows, respectively) or without (control [CON] 2.03% and 1.89% Met of MP for close-up and fresh cows, respectively), fed from 21 ± 6 d prepartum until 16 ± 5 d postpartum. From 17 DIM until dry-off, all cows received RPMet. Daily milk yield was recorded, and milk samples were collected in the first and second weeks after calving to determine their composition. Blood samples were collected before the morning feeding on -14, -7, +1, +7, and +14 d relative to calving. Mortality and morbidity were recorded during the first 60 DIM. Cows supplemented with RPMet had greater milk yield during the first 16 DIM (31.76 vs. 30.37 kg/d; SEM = 1.04, respectively), and had greater milk fat content (4.45 vs. 4.10%; SEM = 0.11, respectively), but not milk total protein (3.47 vs. 3.39%; SEM = 0.04, respectively) and casein contents (2.74 vs. 2.66%; SEM = 0.04, respectively) than CON cows. Cows in RPMet had increased plasma Met concentrations than cows in CON (24.9 vs. 21.0 µmol/L; SEM = 1.2, respectively). Although morbidity was similar between treatments, the culling rate from calving until 60 DIM was lower for RPMet cows than for CON cows (2.4% vs. 12.1%; SEM = 0.02). In conclusion, cows receiving RPMet have greater milk yield, improved milk fat content, and a lower culling rate at 60 DIM than CON cows.


Assuntos
Ração Animal , Dieta , Lactação , Metionina , Leite , Período Periparto , Rúmen , Animais , Bovinos , Metionina/metabolismo , Metionina/administração & dosagem , Feminino , Leite/química , Leite/metabolismo , Dieta/veterinária , Rúmen/metabolismo , Ração Animal/análise
3.
Soft Matter ; 19(10): 1987-2000, 2023 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-36847796

RESUMO

We study the phase behaviour of cholesteric liquid crystal shells with different geometries. We compare the cases of tangential anchoring and no anchoring at the surface, focussing on the former case, which leads to a competition between the intrinsic tendency of the cholesteric to twist and the anchoring free energy which suppresses it. We then characterise the topological phases arising close to the isotropic-cholesteric transition. These typically consist of quasi-crystalline or amorphous tessellations of the surface by half-skyrmions, which are stable at lower and larger shell sizes, respectively. For ellipsoidal shells, defects in the tessellation couple to a local curvature, and according to the shell size, they either migrate to the poles or distribute uniformly on the surface. For toroidal shells, the variations in the local curvature of the surface stabilise heterogeneous phases where cholesteric or isotropic patterns coexist with hexagonal lattices of half-skyrmions.

4.
Phys Rev Lett ; 128(2): 027801, 2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35089738

RESUMO

We study the phase behavior of a quasi-two-dimensional cholesteric liquid crystal shell. We characterize the topological phases arising close to the isotropic-cholesteric transition and show that they differ in a fundamental way from those observed on a flat geometry. For spherical shells, we discover two types of quasi-two-dimensional topological phases: finite quasicrystals and amorphous structures, both made up of mixtures of polygonal tessellations of half-skyrmions. These structures generically emerge instead of regular double twist lattices because of geometric frustration, which disallows a regular hexagonal tiling of curved space. For toroidal shells, the variations in the local curvature of the surface stabilizes heterogeneous phases where cholesteric patterns coexist with hexagonal lattices of half-skyrmions. Quasicrystals and amorphous and heterogeneous structures could be sought experimentally by self-assembling cholesteric shells on the surface of emulsion droplets.

5.
Eur Phys J E Soft Matter ; 45(9): 75, 2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36098879

RESUMO

We study numerically the role of hydrodynamics in the liquid-hexatic transition of active colloids at intermediate activity, where motility induced phase separation (MIPS) does not occur. We show that in the case of active Brownian particles (ABP), the critical density of the transition decreases upon increasing the particle's mass, enhancing ordering, while self-propulsion has the opposite effect in the activity regime considered. Active hydrodynamic particles (AHP), instead, undergo the liquid-hexatic transition at higher values of packing fraction [Formula: see text] than the corresponding ABP, suggesting that hydrodynamics have the net effect of disordering the system. At increasing densities, close to the hexatic-liquid transition, we found in the case of AHP the appearance of self-sustained organized motion with clusters of particles moving coherently.


Assuntos
Coloides , Hidrodinâmica , Movimento (Física)
6.
J Dairy Sci ; 104(1): 683-701, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33162071

RESUMO

Objectives were to determine the effects of an injectable formulation of calcitriol on Ca concentration, risk of clinical diseases, and performance in dairy cows. Cows were blocked by lactation number (1 vs. >1) and calving sequence and, within block, assigned randomly within 6 h of calving to receive subcutaneously vehicle only (CON, n = 450) or 200 (CAL200, n = 450) or 300 µg of 1α,25-dihydroxyvitamin D3 (CAL300, n = 450). Cows were fed the same acidogenic diet prepartum. Blood was sampled before treatment administration and again during the first 11 d postpartum and analyzed for concentrations of ionized Ca (iCa), total Ca (tCa), Mg (tMg), and P (tP), ß-hydroxybutyrate, carboxylated osteocalcin (cOC), and undercarboxylated osteocalcin (uOC). Cows were evaluated for diseases in the first 60 d postpartum. Reproduction and survival were monitored for the first 300 d postpartum. Calcitriol increased concentration of blood iCa (CON = 1.12 vs. CAL200 = 1.23 vs. CAL300 = 1.27 mM), plasma tCa (CON = 2.29 vs. CAL200 = 2.44 vs. CAL300 = 2.46 mM), and plasma tP (CON = 1.72 vs. CAL200 = 2.21 vs. CAL300 = 2.28 mM), and differences were observed during the first 5 d postpartum for iCa and tCa, and the first 7 d postpartum for tP. Concentrations of tMg were lower in calcitriol-treated cows than in CON cows (CON = 0.81 vs. CAL200 = 0.78 vs. CAL300 = 0.75 mM), and differences were observed during the first 5 d postpartum. Calcitriol increased plasma concentrations of cOC (CON = 14.5 vs. CAL200 = 23.0 vs. CAL300 = 19.8 ng/mL) and uOC (CON = 1.6 vs. CAL200 = 3.4 vs. CAL300 = 2.6 ng/mL). Prevalence of subclinical hypocalcemia was less in calcitriol-treated cows (CON = 19.0 vs. CAL200 = 4.7 vs. CAL300 = 9.3%); however, benefits on health were only observed in overconditioned cows (n = 270/1,350). Calcitriol reduced incidence of retained placenta (CON = 14.3 vs. CAL200 = 5.1 vs. CAL300 = 5.9%), puerperal metritis (CON = 12.7 vs. CAL200 = 6.1 vs. CAL300 = 2.5%), and morbidity (CON = 72.1 vs. CAL200 = 57.4 vs. CAL300 = 56.9%) in cows with BCS greater than 3.50, but no benefit on health was observed in cows with BCS equal to or less than 3.50 at parturition. Milk yield did not differ among treatments. Pregnancy at first AI did not differ, but pregnancy rate after the first AI was slower for calcitriol-treated cows because of reduced insemination rate and pregnancy per AI. We found that CAL200 reduced death but increased culling in cows without calving problems. Collectively, results indicate that treatment with calcitriol at parturition was effective in improving concentrations of iCa, tCa, and tP, which reduced the risk of hypocalcemia. Pregnancy rate was reduced by calcitriol treatment, and benefits on health performance were limited to overconditioned cows. Thus, treatment of all cows is not supported, and proper identification of cohorts of cows that benefit from postpartum interventions that increase blood calcitriol or calcium is needed.


Assuntos
Calcitriol/farmacologia , Bovinos/fisiologia , Minerais/sangue , Período Pós-Parto/fisiologia , Vitaminas/farmacologia , Ácido 3-Hidroxibutírico/sangue , Ração Animal , Animais , Cálcio/sangue , Bovinos/sangue , Doenças dos Bovinos/sangue , Doenças dos Bovinos/prevenção & controle , Feminino , Nível de Saúde , Hipocalcemia/sangue , Hipocalcemia/prevenção & controle , Hipocalcemia/veterinária , Lactação/efeitos dos fármacos , Leite , Parto , Gravidez , Reprodução
7.
Soft Matter ; 15(41): 8251-8265, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31553342

RESUMO

The rheological behaviour of an emulsion made of an active polar component and an isotropic passive fluid is studied by lattice Boltzmann methods. Different flow regimes are found by varying the values of the shear rate and extensile activity (occurring, e.g., in microtubule-motor suspensions). By increasing the activity, a first transition occurs from the linear flow regime to spontaneous persistent unidirectional macro-scale flow, followed by another transition either to a (low shear) intermittent flow regime with the coexistence of states with positive, negative, and vanishing apparent viscosity, or to a (high shear) symmetric shear thinning regime. The different behaviours can be explained in terms of the dynamics of the polarization field close to the walls. A maximum entropy production principle selects the most likely states in the intermittent regime.

8.
Transpl Infect Dis ; 16(1): 135-40, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24383613

RESUMO

Trichosporon species are rare etiologic agents of invasive fungal infection in solid organ transplant (SOT) recipients. We report 2 well-documented cases of Trichosporon inkin invasive infection in SOT patients. We also conducted a detailed literature review of Trichosporon species infections in this susceptible population. We gathered a total of 13 cases of Trichosporon species infections. Any type of organ transplantation can be complicated by Trichosporon infection. Bloodstream infections and disseminated infections were the most common clinical presentations. Liver recipients with bloodstream or disseminated infections had poor prognoses. Although the most common species was formerly called Trichosporon beigelii, this species name should no longer be used because of the changes in the taxonomy of this genus resulting from the advent of molecular approaches, which were also used to identify the strains isolated from our patients. Antifungal susceptibility testing highlights the possibility of multidrug resistance. Indeed, Trichosporon has to be considered in cases of breakthrough infection or treatment failure under echinocandins or amphotericin therapy. Voriconazole seems to be the best treatment option.


Assuntos
DNA Fúngico/análise , Empiema/imunologia , Rejeição de Enxerto/prevenção & controle , Transplante de Coração , Hospedeiro Imunocomprometido , Imunossupressores/uso terapêutico , Pneumopatias Fúngicas/imunologia , Transplante de Pulmão , Mediastinite/imunologia , Pericardite/imunologia , Trichosporon/genética , Tricosporonose/imunologia , Adulto , Antifúngicos/uso terapêutico , DNA Intergênico/análise , DNA Ribossômico/análise , Farmacorresistência Fúngica , Empiema/diagnóstico , Empiema/tratamento farmacológico , Humanos , Pneumopatias Fúngicas/diagnóstico , Pneumopatias Fúngicas/tratamento farmacológico , Masculino , Mediastinite/diagnóstico , Mediastinite/tratamento farmacológico , Testes de Sensibilidade Microbiana , Pericardite/diagnóstico , Pericardite/tratamento farmacológico , Derrame Pleural/diagnóstico , Derrame Pleural/tratamento farmacológico , Derrame Pleural/imunologia , Pirimidinas/uso terapêutico , Análise de Sequência de DNA , Triazóis/uso terapêutico , Tricosporonose/diagnóstico , Tricosporonose/tratamento farmacológico , Voriconazol , Adulto Jovem
9.
Phys Rev E ; 109(1-2): 015305, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38366419

RESUMO

The liquid-vapor phase separation is investigated via lattice Boltzmann simulations in three dimensions. After expressing length and time scales in reduced physical units, we combined data from several large simulations (on 512^{3} nodes) with different values of viscosity, surface tension, and temperature, to obtain a single curve of rescaled length l[over ̂] as a function of rescaled time t[over ̂]. We find evidence of the existence of kinetic and inertial regimes with growth exponents α_{d}=1/2 and α_{i}=2/3 over several time decades, with a crossover from α_{d} to α_{i} at t[over ̂]≃1. This allows us to rule out the existence of a viscous regime with α_{v}=1 in three-dimensional liquid-vapor isothermal phase separation, differently from what happens in binary fluid mixtures. An in-depth analysis of the kinetics of the phase separation process, as well as a characterization of the morphology and the flow properties, are further presented in order to provide clues into the dynamics of the phase-separation process.

10.
Heliyon ; 10(7): e28734, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38617959

RESUMO

Rationale and objectives: Imaging plays a key role in Slipped Capital Femoral Epiphysis diagnosis and severity assessment. In the last two decades, signs and measurements emerged in literature showed potential to help in SCFE diagnosis and tailoring treatment. The purpose of this review is to collect and discuss new imaging signs, measurements, and techniques according to investigations published after 2000 to improve SCFE diagnosis. Material and methods: The PubMed, Scopus, and Science Direct databases were used to search for relevant articles related to imaging in SCFE diagnosis from January 2000 to March 2023. Article selection and review was performed by two board-certified radiologists). Article quality assessment were conducted by authors using QUADAS-2 and SANRA evaluation tools. Results: The research resulted in a total of 2577 articles. After duplicates removal and abstract analysis, 28 articles were finally selected for full-text analysis. Seventeen articles were focused on Radiographs, 6 on CT, 1 on both Radiographs and CT, 4 on MRI. No study focused on ultrasound was selected. Conclusions: Use of modified Klein's line and S-sign may improve radiographs accuracy in daily routine. Lucency sign may help in early diagnosis on radiographs. Preoperative CT may be useful in planning a tailored treatment predicting SCFE severity and instability. MRI is the most accurate modality to diagnose SCFE at early stage. Nevertheless, it cannot be used to predict the risk of contralateral SCFE. Risk prediction can be assessed with radiographs, using a new rapid mOBS. Further investigation and validation of these sign is needed.

11.
Med Mycol ; 48(8): 1116-20, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20662631

RESUMO

The use of improved microbiological procedures associated with molecular techniques has increased the identification of Candida bloodstream infections, even if the isolation of more than one species by culture methods remains uncommon. We report the cases of two children presenting with severe gastrointestinal disorders and other risk factors that contribute to Candida infections. In the first patient, C. albicans DNA was initially detected by a nested-amplification and C. tropicalis was found later during hospitalization, while blood cultures were persistently negative. In the second child, there was amplification of C. albicans and C. glabrata DNA in the same samples, but blood cultures yielded only C. albicans. Both patients received antifungal therapy but had unfavorable outcomes. These two cases illustrate that PCR was more successful than culture methods in detecting Candida in the bloodstream of high risk children, and was also able to detect the presence of more than one species in the same patient that might impact therapy when the fungi are resistant to azole compounds.


Assuntos
Candidemia/diagnóstico , Micologia/métodos , Reação em Cadeia da Polimerase/métodos , Candida albicans/isolamento & purificação , Candida glabrata/isolamento & purificação , Candida tropicalis/isolamento & purificação , Candidemia/microbiologia , Criança , Pré-Escolar , Estado Terminal , Feminino , Gastroenteropatias/complicações , Humanos , Masculino
12.
Sci Rep ; 10(1): 15936, 2020 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-32985576

RESUMO

We use computer simulations to study the morphology and rheological properties of a bidimensional emulsion resulting from a mixture of a passive isotropic fluid and an active contractile polar gel, in the presence of a surfactant that favours the emulsification of the two phases. By varying the intensity of the contractile activity and of an externally imposed shear flow, we find three possible morphologies. For low shear rates, a simple lamellar state is obtained. For intermediate activity and shear rate, an asymmetric state emerges, which is characterized by shear and concentration banding at the polar/isotropic interface. A further increment in the active forcing leads to the self-assembly of a soft channel where an isotropic fluid flows between two layers of active material. We characterize the stability of this state by performing a dynamical test varying the intensity of the active forcing and shear rate. Finally, we address the rheological properties of the system by measuring the effective shear viscosity, finding that this increases as active forcing is increased-so that the fluid thickens with activity.

14.
G Ital Dermatol Venereol ; 143(3): 225-6, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18833066

RESUMO

The authors describe a case of Behçet's syndrome or ''silk route disease'' in a patient from the Democratic Republic of Congo. The patient arrived in hospital suffering from an acute episode of febrile erythema nodosum, which was diagnosed as type 2 leprosy reaction. His history reported recurrent oral aphthae and during hospitalization ulcers on the scrotum and pathergy were observed. A diagnosis of Behçet's disease was made. The patient is HLA B51 negative and the scientific literature confirms that testing for the presence of this allele is negative in the 10 cases of Behçet's disease reported from Sub-Saharan countries.


Assuntos
Síndrome de Behçet/diagnóstico , Adulto , República Democrática do Congo , Humanos , Masculino
15.
Eur J Clin Nutr ; 60(1): 58-61, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16132056

RESUMO

AIM: To evaluate the current use of Home Parenteral Nutrition (HPN) in a Southern European region. SUBJECTS AND METHODS: A total of 159 (86 m, 73 f) HPN patients, mean age 60.1 +/- 14.2 years, BMI 18.8 +/- 3.3kg/m2, consecutively referred to the Artificial Nutrition outpatient Unit of the Federico II University Hospital in Naples (Italy), from January 2000 to December 2002 and treated for at least 4 weeks. Retrospective evaluation of baseline disease, indications and duration of HPN treatment, type of venous access, complications. RESULTS: In all, 140 (88%) were cancer and 19 (12%) noncancer patients. Main indications were carcinosis in 68 for total, and hypophagia/dysphagia in 62 patients for partial/integrative (to oral-enteral nutrition) HPN; mean duration of HPN was 81.45 +/- 110.86 days of treatment and infection rate 2.89% in the whole population and 2.66% in the 36 patients treated for more than 3 months. No other major complications have been observed. CONCLUSION: HPN is confirmed to be a safe and effective treatment when prescribed and administered by a trained team.


Assuntos
Infecções/epidemiologia , Neoplasias/terapia , Nutrição Parenteral no Domicílio , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Infecções/etiologia , Itália , Masculino , Pessoa de Meia-Idade , Cuidados Paliativos/métodos , Nutrição Parenteral no Domicílio/efeitos adversos , Nutrição Parenteral no Domicílio/estatística & dados numéricos , Equipe de Assistência ao Paciente/normas , Sistema de Registros , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
17.
Microbes Infect ; 1(4): 273-8, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10602660

RESUMO

We investigated the relationship between antibody response to the major Paracoccidioides brasiliensis antigen, a 43-kDa glycoprotein, and the two paracoccidioidomycosis (PCM) clinical presentations, the juvenile and the adult forms. Total immunoglobulin G (IgG), IgG isotypes, and IgA anti-gp43 antibodies were determined by enzyme-linked immunosorbent assay in patients'sera. Juvenile PCM patients had higher (P =.003) IgG anti-gp43 levels than adult form patients. IgG1 subclass levels, however, were comparable between the two clinical forms. Patients with the juvenile form had higher (P <. 001) IgG4, but lower (P =.03) IgG2 levels than patients with the adult form. The IgG4 isotype, regulated by interleukin 4, was found in all juvenile form patients but in only 12% of the adult form patients. In contrast, high levels of the IgG2 isotype, regulated by interferon-gamma, were found in 41% of the adult PCM patients, mainly those with a more benign disease, but in only 12% of the juvenile patients. IgG3 was either absent or detected at low levels. These results demonstrate, for the first time, specific IgG4 antibodies in the humoral immune response of patients with an endemic deep mycosis and suggest that the switch to the IgG subclasses in PCM is regulated by the patients' T-helper subset (Th-1 or Th-2) dominant cytokine profile. A possible role for IgG4 in the immunopathogenesis of the juvenile, more severe form of the disease is discussed. Finally, IgA was found mainly in adult form patients, probably as a result of the chronic mucosal antigenic stimulation characteristic of this form.


Assuntos
Anticorpos Antifúngicos/sangue , Antígenos de Fungos , Proteínas Fúngicas , Glicoproteínas/imunologia , Isotipos de Imunoglobulinas/sangue , Oligossacarídeos/imunologia , Paracoccidioides/imunologia , Paracoccidioidomicose/imunologia , Adolescente , Adulto , Anticorpos Antifúngicos/imunologia , Criança , Contraimunoeletroforese , Citocinas/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina A/sangue , Imunoglobulina A/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Isotipos de Imunoglobulinas/imunologia , Células Th1/imunologia , Células Th2/imunologia
18.
Pediatr Infect Dis J ; 13(6): 510-5, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8078739

RESUMO

This report describes clinical and immunologic features of five illustrative cases of paracoccidioidomycosis in previously healthy children. All had disseminated disease and two of them died despite treatment. The major clinical presentation in four patients was fever and diffuse superficial and intraabdominal adenopathy, with or without hepatosplenomegaly. Other sites were also affected: three patients had multiple osteoarticular lesions, occasionally with intense tissue destruction; two had cutaneous eruptions; two had pericardial effusions; and two had pulmonary involvement, once considered an organ spared in the young. We detected variable lymphocyte responses to mitogens and to Candida albicans antigen and non-responsiveness to Paracoccidioides brasiliensis cell wall antigen. High concentrations of serum immunoglobulins and anti-P. brasiliensis antibodies were present. These immune alterations tended to resolve with treatment, suggesting a reversible nature of the immune defect. We conclude that this mycosis has a high morbidity and mortality in children, which is probably related to an antigen-specific immunodeficiency. Further studies are needed to increase knowledge of this mycosis in children.


Assuntos
Paracoccidioidomicose/imunologia , Paracoccidioidomicose/fisiopatologia , Doença Aguda , Candida albicans/imunologia , Criança , Evolução Fatal , Feminino , Humanos , Imunidade Celular , Hospedeiro Imunocomprometido , Ativação Linfocitária , Masculino , Paracoccidioides/imunologia , Paracoccidioidomicose/diagnóstico , Paracoccidioidomicose/terapia
19.
Virchows Arch ; 438(2): 154-8, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11253117

RESUMO

In order to assess the suitability of cryopreserved neoplastic tissues for xenografting into nude (nu/nu) mice, we compared the take rate in 28 samples of pancreatic ductal carcinoma. Eleven fresh samples were implanted in nu/nu mice, and 17 were frozen in cryopreserving solution and implanted at a later time. All samples were examined for the presence of neoplastic tissue in cryostat sections. A total of 15 tumors grew in the animals; five from the freshly implanted samples and ten from those cryopreserved. Ten xenografted tumors were characterized for alterations in p53, K-ras, and p16 genes, which were found in six, eight, and nine cases, respectively. Our results demonstrate that the take rate for xenografting is comparable between cryopreserved and fresh tissue samples. The procedure allows for the exchange of tumor material between institutions and permits the establishment of centralized facilities for the storage of an array of different primary tumor samples suitable for the production of in vivo models of cancers.


Assuntos
Carcinoma de Células das Ilhotas Pancreáticas/patologia , Criopreservação , Ductos Pancreáticos/patologia , Neoplasias Pancreáticas/patologia , Adulto , Idoso , Animais , Carcinoma de Células das Ilhotas Pancreáticas/genética , Análise Mutacional de DNA , DNA de Neoplasias/análise , Feminino , Deleção de Genes , Genes p16/genética , Genes p53/genética , Genes ras/genética , Humanos , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Transplante de Neoplasias , Neoplasias Pancreáticas/genética , Reação em Cadeia da Polimerase , Transplante Heterólogo
20.
Am J Trop Med Hyg ; 54(1): 7-12, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8651374

RESUMO

To characterize the immune dysfunction associated with paracoccidioidomycosis, we studied the in vitro lymphocyte reactivity to phytohemagglutinin (PHA), pokeweed mitogen (PWM), a Candida albicans antigen (CMA), and a Paracoccidioides brasiliensis antigen (PbAg) in 32 patients with the acute and the chronic form of the disease before or during the initial phase of treatment and after clinical cure. We also studied, as controls, 30 healthy individuals, 15 of them immune to P. brasiliensis. Results showed a strong hyporesponsiveness to the PbAg while responses to mitogens and CMA were comparable with those of controls. Patients with the acute form of the disease (usually more severe) had more marked PbAg hyporesponsiveness than those with the chronic form. After patients' clinical cure, PbAg proliferative responses were similar to controls and greater than those seen before pretreatment. Changes in other parameters were also seen in the treated patients; skin test anergy to paracoccidioidin, high levels of anti-P. brasiliensis antibodies, leukocytosis, and eosinophilia. These changes were usually more intense in patients with the acute form of the disease. The post-treatment CD4+, CD8+, and total lymphocyte counts were similar to those of controls. Correlation between these parameters and the lymphoproliferative responses to the various stimuli was only found with PbAg: PbAg responses correlated inversely with eosinophil and anti P. brasiliensis antibody levels. Overall, our results demonstrate an antigen-specific-cellular immunity defect, which is reversible with treatment and possibly related to a T helper cell-2 pattern of immune response during active disease.


Assuntos
Antígenos de Fungos/imunologia , Tolerância Imunológica , Paracoccidioidomicose/imunologia , Adolescente , Adulto , Anticorpos Antifúngicos/sangue , Criança , Humanos , Hipersensibilidade Tardia , Ativação Linfocitária , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA