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1.
Int J Tuberc Lung Dis ; 26(5): 392-398, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35505478

RESUMO

BACKGROUND: The Philippines aims to accelerate TB reduction through the provision of universally accessible and affordable services. The objectives of this paper are to estimate the costs of TB services and interventions using a health systems´ perspective, and to explore cost differences in service delivery via primary care facilities or hospitals.METHODS: Data were collected from a multi-stage stratified random sampling of 28 facilities in accordance with Global Health Cost Consortium costing standards and analysis tools. Unit costs (in US$) estimated using top-down (TD) and bottom-up (BU) approaches, are summarised following Value TB reporting standards and by broad facility type.RESULTS: Cost of delivering 32 TB services and eight interventions varied by costing method and delivery platform. Average BU costs ranged from US$0.38 for treatment support visits, US$2.5 for BCG vaccination, US$19.48 for the Xpert® MTB/RIF test to US$3,677 for MDR-TB treatment using the long regimen. Delivering TB care in hospitals was generally more costly than in primary care facilities, except for TB prevention in children and MDR-TB treatment using the long regimen.CONCLUSION: Comprehensive costing data for TB care in the Philippines are now available to aid in the design, planning, and prioritisation of delivery models to End TB.


Assuntos
Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose Pulmonar , Criança , Custos de Cuidados de Saúde , Humanos , Filipinas
2.
Int J Tuberc Lung Dis ; 25(12): 1013-1018, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34886932

RESUMO

BACKGROUND: There is a dearth of economic analysis required to support increased investment in TB in India. This study estimates the costs of TB services from a health systems´ perspective to facilitate the efficient allocation of resources by India´s National Tuberculosis Elimination Programme.METHODS: Data were collected from a multi-stage, stratified random sample of 20 facilities delivering TB services in two purposively selected states in India as per Global Health Cost Consortium standards and using Value TB Data Collection Tool. Unit costs were estimated using the top-down (TD) and bottom-up (BU) methodology and are reported in 2018 US dollars.RESULTS: Cost of delivering 50 types of TB services and four interventions varied according to costing method. Key services included sputum smear microscopy, Xpert® MTB/RIF and X-ray with an average BU costs of respectively US$2.45, US$17.36 and US$2.85. Average BU cost for bacille Calmette-Guérin vaccination, passive case-finding, TB prevention in children under 5 years using isoniazid and first-line drug treatment in new pulmonary and extrapulmonary TB cases was respectively US$0.76, US$1.62, US$2.41, US$103 and US$98.CONCLUSION: The unit cost of TB services and outputs are now available to support investment decisions, as diagnosis algorithms are reviewed and prevention or treatment for TB are expanded or updated in India.


Assuntos
Mycobacterium tuberculosis , Tuberculose Pulmonar , Tuberculose , Criança , Pré-Escolar , Análise Custo-Benefício , Humanos , Índia , Sensibilidade e Especificidade , Escarro , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Tuberculose/prevenção & controle , Tuberculose Pulmonar/diagnóstico
3.
Int J Tuberc Lung Dis ; 25(12): 1019-1027, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34886933

RESUMO

BACKGROUND: Patient-centred care along with optimal financing of inpatient and outpatient services are the main priorities of the Georgia National TB Programme (NTP). This paper presents TB diagnostics and treatment unit cost, their comparison with NTP tariffs and how the study findings informed TB financing policy.METHODS: Top-down (TD) and bottom-up (BU) mean unit costs for TB interventions by episode of care were calculated. TD costs were compared with NTP tariffs, and variations in these and the unit costs cost composition between public and private facilities was assessed.RESULTS: Outpatient interventions costs exceeded NTP tariffs. Unit costs in private facilities were higher compared with public providers. There was very little difference between per-day costs for drug-susceptible treatment and NTP tariffs in case of inpatient services. Treatment day financing exceeded actual costs in the capital (public facility) for drug-resistant TB, and this was lower in the regions.CONCLUSION: Use of reliable unit costs for TB services at policy discussions led to a shift from per-day payment to a diagnosis-related group model in TB inpatient financing in 2020. A next step will be informing policy decisions on outpatient TB care financing to reduce the existing gap between funding and costs.


Assuntos
Custos de Cuidados de Saúde , Setor Privado , Tuberculose , Humanos , Assistência Ambulatorial , Tuberculose/economia , Tuberculose/epidemiologia , República da Geórgia
4.
Int J Tuberc Lung Dis ; 25(12): 1028-1034, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34886934

RESUMO

BACKGROUND: The reduction of Kenya´s TB burden requires improving resource allocation both to and within the National TB, Leprosy and Lung Disease Program (NTLD-P). We aimed to estimate the unit costs of TB services for budgeting by NTLD-P, and allocative efficiency analyses for future National Strategic Plan (NSP) costing.METHODS: We estimated costs of all TB interventions in a sample of 20 public and private health facilities from eight counties. We calculated national-level unit costs from a health provider´s perspective using bottom-up (BU) and top-down (TD) approaches for the financial year 2017-2018 using Microsoft Excel and STATA v16.RESULTS: The mean unit cost for passive case-finding (PCF) was respectively US$38 and US$60 using the BU and TD approaches. The unit BU and TD costs of a 6-month first-line treatment (FLT) course, including monitoring tests, was respectively US$135 and US$160, while those for adult drug-resistant TB (DR-TB) treatment was respectively US$3,230.28 and US$3,926.52 for the 9-month short regimen. Intervention costs highlighted variations between BU and TD approaches. Overall, TD costs were higher than BU, as these are able to capture more costs due to inefficiency (breaks/downtime/leave).CONCLUSION: The activity-based TB unit costs form a comprehensive cost database, and the costing process has built-in capacity within the NTLD-P and international TB research networks, which will inform future TB budgeting processes.


Assuntos
Atenção à Saúde , Custos de Cuidados de Saúde , Instalações de Saúde , Tuberculose , Humanos , Quênia , Tuberculose/economia
5.
Artigo em Inglês | MEDLINE | ID: mdl-10884934

RESUMO

The stratum corneum is a complex biological material characterized by very low permeability to water and most other molecules. This material may be thought of as a 'porous medium' composed of impermeable and permeable regions. Intercellular lipid membranes in the stratum corneum are postulated to exist in a mixture of two phases: solid (i.e. impermeable) and liquid crystalline (permeable). The corneocyte envelope is classified as impermeable. Diffusion mechanisms of solutes within, across and between the intercellular lamellae are discussed. This model represents a refinement of previous theories about the physical structures responsible for the low observed permeability of the stratum corneum.


Assuntos
Epiderme/metabolismo , Difusão , Células Epidérmicas , Epiderme/anatomia & histologia , Espaço Extracelular/metabolismo , Humanos , Metabolismo dos Lipídeos , Lipídeos/química , Permeabilidade , Porosidade , Relação Estrutura-Atividade , Água/metabolismo
6.
J Investig Dermatol Symp Proc ; 3(2): 101-4, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9734821

RESUMO

The 1H and 2H magnetic resonance signals from pig stratum corneum were measured as a function of hydration. The 1H free induction decay contained two components, one motionally restricted and the other isotropically mobile on the timescale of 10(-5) s. From its T2 decay, the mobile signal was further subdivided into two components; one, which was 11% of the signal and 5.5% of the mass of the dehydrated stratum corneum, was assigned to nonaqueous tissue (likely hydrocarbons) and the other to water. As water content increased from 0 to 0.25 gH2O/gSC, the second moment of the motionally restricted signal decreased from 5.4 x 10(9) to 3.6 x 10(9) s(-2), whereas the water T2 time increased from less than 0.3 ms to 3.3 ms. The 2H quadrupolar echo from stratum corneum hydrated in 2H2O had a signal from motionally restricted deuterons, attributed to deuterons exchanged onto O-H and N-H groups, and a mobile signal from 2H2O. The amount of exchange, 9.5% of the hydrogen sites in the motionally restricted fraction, was close to the number of exchangeable sites on keratin, the most abundant protein in stratum corneum. Our results are consistent with a model in which the bulk of the water interacts closely with the corneocytes in stratum corneum.


Assuntos
Água Corporal/metabolismo , Epiderme/metabolismo , Espectroscopia de Ressonância Magnética , Animais , Água Corporal/química , Água Corporal/fisiologia , Deutério , Suínos , Porco Miniatura
7.
Biochemistry ; 36(25): 7717-25, 1997 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-9201912

RESUMO

The permeability of mammalian skin is determined in large part by lamellar lipid domains packed between cells of the upper layer of the epidermis, the stratum comeum. Although these lamellae have features in common with typical biological membranes, they differ in having a lipid population composed mainly of ceramides, cholesterol, and free fatty acids. In our initial studies of the relationship between lipid composition and phase behavior in this unusual system, we used deuterium NMR [Kitson et al. (1994) Biochemistry 33, 6707-6715] to examine aqueous dispersions of nonhydroxylated bovine brain ceramide, cholesterol, and perdeuterated palmitic acid, and found complex phase behavior as a function of temperature and pH, whereas analogous dispersions in which sphingomyelin replaced ceramide resulted in spectra consistent with a fluid lamellar phase under the same conditions. To extend these observations, we examined the same dispersions at pH 5.2 by means of X-ray diffraction. The significant findings are as follows: (1) the ceramide dispersions form complex crystalline phases between room temperature and about 40 degrees C; (2) the majority of the crystalline cholesterol is not in a separate phase; and (3) the analogous sphingomyelin dispersions form a fluid lamellar phase under the same conditions. We conclude that ceramides, even in the presence of considerable mole fractions of cholesterol, can form crystalline lamellar structures. We suggest that the existence of such structures in stratum corneum may be important in the function of the epidermal permeability barrier, and that the interaction between ceramide and cholesterol in other biological membranes may result in regions having unique physical properties.


Assuntos
Permeabilidade da Membrana Celular , Epiderme/fisiologia , Membranas Artificiais , Animais , Bovinos , Modelos Biológicos , Difração de Raios X
8.
Neuroreport ; 8(3): 695-8, 1997 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-9106749

RESUMO

Positron emission tomography (PET) was used to identify the brain regions activated during the 'inner signing' of sentences in subjects who were profoundly deaf and normally communicated using sign language. Although this appeared to involve the internal representation of hand and arm movements in space, it activated the left inferior frontal cortex rather than visuo-spatial areas. The activated region corresponds to that engaged during the silent articulation of sentences in hearing subjects. This suggests that 'inner signing' is mediated by similar regions to inner speech, and is consistent with neuropsychological data implicating the left hemisphere in the generation of sign language.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Encéfalo/fisiopatologia , Surdez , Neurônios/fisiologia , Língua de Sinais , Pensamento/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular , Audição , Humanos , Pessoa de Meia-Idade , Tomografia Computadorizada de Emissão
9.
Biophys J ; 67(4): 1562-73, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7819488

RESUMO

Deuterium NMR was used to characterize model membrane systems approximating the composition of the intercellular lipid lamellae of mammalian stratum corneum (SC). The SC models, equimolar mixtures of ceramide:cholesterol:palmitic acid (CER:CHOL:PA) at pH 5.2, were contrasted with the sphingomyelin:CHOL:PA (SPM:CHOL:PA) system, where the SPM differs from the CER only in the presence of a phosphocholine headgroup. The lipids were prepared both as oriented samples and as multilamellar dispersions, and contained either perdeuterated palmitic acid (PA-d31) or [2,2,3,4,6-2H5]CHOL (CHOL-d5). SPM:CHOL:PA-d31 formed liquid-ordered membranes over a wide range of temperatures, with a maximum order parameter of approximately 0.4 at 50 degrees C for positions C3-C10 (the plateau region). The quadrupolar splitting at C2 was significantly smaller, suggesting an orientational change at this position, possibly because of hydrogen bonding with water and/or other surface components. A comparison of the longitudinal relaxation times obtained at theta = 0 degrees and 90 degrees (where theta is the angle between the normal to the glass plates and the magnetic field) revealed a significant T1Z anisotropy for all positions. In contrast to the behavior observed with the SPM system, lipid mixtures containing CER exhibited a complex polymorphism. Between 20 and 50 degrees C, a significant portion of the entire membrane (as monitored by both PA-d31 and CHOL-d5) was found to exist as a solid phase, with the remainder either a gel or liquid-ordered phase. The proportion of solid decreased as the temperature was increased and disappeared entirely above 50 degrees C. Between 50 and 70 degrees C, the membrane underwent a liquid-ordered to isotropic phase transition. These transitions were reversible but displayed considerable hysteresis, especially the conversion from a fluid phase to solid. The order profiles, relaxation behavior, and angular dependence of these parameters suggest strongly that both the liquid-ordered CER- and SPM-membranes are bilayers. The unusual phase behavior observed for the CER-system, particularly the observation of solid-phase lipid at physiological temperatures, may provide insight into the functioning of the permeability barrier of stratum corneum.


Assuntos
Epiderme/ultraestrutura , Membranas Intracelulares/ultraestrutura , Lipossomos , Lipídeos de Membrana , Animais , Bovinos , Ceramidas , Colesterol , Deutério , Cinética , Espectroscopia de Ressonância Magnética/métodos , Mamíferos , Ácido Palmítico , Ácidos Palmíticos , Esfingomielinas , Relação Estrutura-Atividade , Termodinâmica
10.
J Child Psychol Psychiatry ; 35(5): 917-34, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7962248

RESUMO

Psychiatric screening questionnaires for deaf children and adolescents were piloted in a group of 62 children, aged 11-16 years, attending a residential school. The questionnaires, Parent's Checklist (PCL) and Teacher's Checklist (TCL) were then used to screen a group of 93 children attending one Deaf School and three Hearing Impaired Units (HIU). Psychiatric assessments were conducted with a highly structured diagnostic interview, the Child Assessment Schedule (CAS). The interview with signing deaf children was conducted with a sign language interpreter. The prevalence of psychiatric disorder in the whole group was 50.3%, 42.4% in the group attending the Deaf School and 60.9% for the group attending the HIUs. An aetiological model of psychiatric disorder in this group is proposed.


Assuntos
Surdez/epidemiologia , Perda Auditiva/epidemiologia , Transtornos Mentais/epidemiologia , Adolescente , Criança , Métodos de Comunicação Total , Comorbidade , Estudos Transversais , Surdez/psicologia , Educação Inclusiva , Inglaterra/epidemiologia , Feminino , Perda Auditiva/psicologia , Humanos , Incidência , Masculino , Programas de Rastreamento , Transtornos Mentais/diagnóstico , Transtornos Mentais/psicologia , Determinação da Personalidade
11.
Biochemistry ; 33(21): 6707-15, 1994 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-8204605

RESUMO

The permeability barrier of mammalian skin is found in unusual intercellular domains in the upper layers of the epidermis, and is composed mainly of three lipid classes: ceramide, cholesterol, and free fatty acid. These are organized as lamellae, but the details of lipid organization are not precisely known. To examine the relationship between lipid composition and phase behavior, aqueous dispersions of bovine brain ceramide, cholesterol, and perdeuterated palmitic acid were examined by 2H NMR and compared to analogous systems in which sphingomyelin replaced ceramide. The sphingomyelin systems give rise as expected to a stable fluid lamellar signal over the temperature range 20-75 degrees C and pH 5.2-7.4, whereas the ceramide dispersions show complex polymorphism as a function of both temperature and pH. Prominent features of the ceramide dispersions containing cholesterol are phase coexistence and the presence of a "solid" phase in which molecular motion is more inhibited than in a classical phospholipid gel phase: T1z measurements indicate that lateral diffusion of the palmitic acid probe effectively does not occur. In the absence of cholesterol, a fluid lamellar signal is not observed, but the appearance of a "solid" signal is also influenced by the pH. In the presence of cholesterol, a fluid lamellar signal is present at 50 degrees C, and the 2H NMR order parameter profile is very similar to that derived from the analogous sphingomyelin dispersions.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Lipídeos/fisiologia , Fenômenos Fisiológicos da Pele , Animais , Bovinos , Concentração de Íons de Hidrogênio , Bicamadas Lipídicas , Espectroscopia de Ressonância Magnética , Modelos Biológicos , Permeabilidade , Absorção Cutânea , Temperatura
13.
J Endocrinol ; 137(3): 391-401, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8396618

RESUMO

The multifactorial control of ACTH is well established. We wished to establish and characterize an in-vitro perifusion system, using equine anterior pituitary cells and physiological concentrations of secretagogues, to investigate factors which affect the dynamics of ACTH secretion. Anterior pituitary tissue was divided for dispersion into cells with collagenase, trypsin or dispase, or by mechanical dispersion. After dispersal followed by 18-h incubation, cells were perifused and the ACTH response to 10-min pulses of arginine vasopressin (AVP; 100 nmol/l), corticotrophin-releasing hormone (CRH; 0.01 nmol/l), and AVP (100 nmol/l) plus CRH (0.01 nmol/l) determined. ACTH responses to these secretagogues were lower (P < 0.05) in cells prepared using the enzymes dispase and trypsin than with the enzyme collagenase. Cells prepared by mechanical methods were not responsive. Collagenase-prepared cells were used in subsequent experiments. In dose-response studies (10-min pulse length), a steep CRH-ACTH dose-response curve was obtained with the minimum effective concentration of CRH between 0.001 and 0.01 nmol/l, and a maximum effective concentration of 1.0 nmol/l. A less steep AVP-ACTH dose-response curve was obtained with a minimum effective concentration of AVP between 0.5 and 5 nmol/l, and no plateau in response up to 5000 nmol AVP/l. Increasing the incubation time between cell preparation and stimulation with AVP from 18 h to 90 h significantly (P < 0.01) increased the ACTH response. Repeated stimulation by AVP (100 nmol/l) or CRH (0.01 nmol/l) (5-min pulses every 30 min for 23 pulses) produced ACTH responses which decreased in an approximately exponential curve with time. When AVP and CRH were given at physiological concentrations, pulse lengths and pulse frequency, the ACTH response to repeated 1-min pulses of AVP, measured as height above basal secretion, was potentiated by the addition of CRH (1, 2.5, 5, 10 and 20 pmol/l) as a constant perifusion at all AVP concentrations tested (1 nmol AVP/l, P < 0.02; 10 nmol AVP/l, P < 0.0005; 25 nmol AVP/l, P < 0.0005). During the 1-min AVP pulse, the AVP concentration at the level of the cells was 30% of the expected concentration. Potentiation was increased both by increasing AVP concentration (P < 0.00005) and by increasing CRH concentration (P < 0.00005) up to 5 pmol CRH/l. The ACTH height response to repeated AVP stimulation significantly (P = 0.034) decreased with time, independent of CRH and AVP concentration. There was a significant (P = 0.014) decrease in ACTH response to CRH infusion with time, independent of CRH concentration.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Hormônio Adrenocorticotrópico/metabolismo , Adeno-Hipófise/metabolismo , Animais , Arginina Vasopressina/farmacologia , Células Cultivadas , Colagenases/metabolismo , Hormônio Liberador da Corticotropina/farmacologia , Relação Dose-Resposta a Droga , Feminino , Cavalos , Masculino , Modelos Biológicos , Perfusão , Adeno-Hipófise/citologia , Adeno-Hipófise/efeitos dos fármacos
14.
J Endocrinol ; 137(3): 403-12, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8396619

RESUMO

Perifused equine anterior pituitary cells were used to investigate the effect of cortisol on the ACTH response to pulses of corticotrophin-releasing hormone (CRH; 0.01 nmol/l) and arginine vasopressin (AVP; 100 nmol/l), given for 5 min every 30 min for 690 min and ACTH measured in 5-min fractions. At the fourth pulse of secretagogue (0 min), a constant perifusion with cortisol began (0 nmol/l (control), 100, 200, 500, 5000 and 50,000 nmol/l) and continued until the ninth pulse (150 min). For each pulse of secretagogue, the amount of ACTH (pmol) secreted in response to each pulse (ACTH response area), the highest concentration of ACTH (microgram/l) measured after each pulse (peak height) and the mean ACTH in the three prepulse fractions (ACTH baseline) were determined. Data from control columns in each experiment were fitted by least squares to an exponential function to produce a mean control value for each end-point; results in all columns were expressed as a percentage of the mean control values. The addition of cortisol had a highly significant negative effect on ACTH response area, peak height and baseline at all times from +30 to +240 min (columns given cortisol compared with the mean of control column values by t-test). Analysis of variance of the data showed that the higher the cortisol concentration, the quicker the ACTH response area (P = 0.0072) and peak height (P = 0.002) decreased to < 50% of mean control, and the greater the maximum percentage change (suppression) in ACTH response area (P < 0.0001) and peak height (P < 0.0001). The maximum percentage change (suppression) in baseline was independent of cortisol concentration. At +30 min after the start of cortisol perifusion, the ACTH response area in CRH columns was significantly lower than in AVP columns (P = 0.0088), and remained lower 90 min after the end of perifusion (P = 0.0084) but the maximum percentage change (suppression) was not different between secretagogues. ACTH peak height was significantly (P < 0.0268) lower in CRH than in AVP columns (from +30 min until 180 min after the end of cortisol perifusion) and the maximum percentage change (suppression) was also greater (P = 0.0011) in CRH columns. This study shows the effect of different concentrations of cortisol on CRH- and AVP-induced ACTH secretion by equine anterior pituitary cells, and the time-course for ACTH responses to be inhibited by, and recover from, cortisol perifusion.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Hormônio Adrenocorticotrópico/metabolismo , Hidrocortisona/farmacologia , Adeno-Hipófise/metabolismo , Animais , Arginina Vasopressina/farmacologia , Células Cultivadas , Hormônio Liberador da Corticotropina/farmacologia , Depressão Química , Feminino , Cavalos , Masculino , Perfusão , Adeno-Hipófise/citologia , Adeno-Hipófise/efeitos dos fármacos , Fatores de Tempo
15.
Biochem Biophys Res Commun ; 188(3): 1247-52, 1992 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-1445357

RESUMO

During formation of the intercellular membranes of mammalian stratum corneum, sphingomyelin and glucosylceramide are converted enzymatically to ceramide. To model in isolation the possible effect of such a lipid modification on the phase behavior of the ensemble, we used proton and deuterium nuclear magnetic resonance to compare an equimolar dispersion of bovine brain sphingomyelin, cholesterol, and perdeuterated palmitic acid (at pH 6.2), with an equivalent dispersion in which bovine brain ceramide was substituted for sphingomyelin. While the sphingomyelin dispersions remain in a homogeneous fluid lamellar phase from 20-75 degrees C under these conditions, those containing ceramide display complex polymorphism.


Assuntos
Fluidez de Membrana , Membranas Artificiais , Esfingomielinas/química , Ceramidas/química , Colesterol/química , Epiderme/fisiologia , Temperatura Alta , Espectroscopia de Ressonância Magnética , Modelos Químicos , Ácido Palmítico , Ácidos Palmíticos/química
16.
Biochim Biophys Acta ; 1111(1): 127-33, 1992 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-1390858

RESUMO

Cholesterol 3-sulphate (CS) is a component of the intercellular lipid found in the uppermost layer of human epidermis (the 'stratum corneum') and is thought to play an important role in tissue cohesion. In this investigation we have compared the influence of cholesterol (CH) and CS on the gel-to-liquid crystalline phase behaviour, the polymorphic phase behaviour, and the hydrocarbon order profile in selected model membranes. It is shown that in sphingomyelin (SPM) systems, the presence of equimolar amounts of either CH or CS eliminates the gel-to-liquid crystalline transition as detected by calorimetry. Similarly, in 1-palmitoyl,2-oleoyl-phosphatidylethanolamine (POPE) dispersions containing a perdeuterated palmitoyl chain (POPE-d31), it is shown that both CH and CS exert an ordering effect as determined by 2H-NMR techniques, however, CS is less potent at temperatures both above and below that of the main transition for the native phospholipid. Alternatively, in mixed systems containing dioleoylphosphatidylethanolamine (DOPE) and SPM (DOPE/SPM, 6:1 mol/mol) CH promotes thermotropic L alpha-->HII phase transitions, whereas CS stabilizes the bilayer organization. These bilayer stabilization effects can be diminished by addition of Ca2+. These effects are consistent with a larger area per molecule of CS as compared to CH, presumably related to the presence of the negatively charged sulphate moiety of CS.


Assuntos
Membrana Celular/efeitos dos fármacos , Ésteres do Colesterol/farmacologia , Membrana Celular/química , Colesterol/farmacologia , Hidrocarbonetos/química , Bicamadas Lipídicas
17.
Br J Hosp Med ; 44(5): 353-6, 1990 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2276003

RESUMO

This article provides an introduction to the neglected area of psychiatry and prelingual deafness. 'Deafness' refers to prelingual profound deafness except where indicated, although many of the observations apply to some extent to prelingually partially hearing people.


Assuntos
Surdez/complicações , Transtornos Mentais/complicações , Comunicação , Surdez/classificação , Surdez/psicologia , Perda Auditiva/psicologia , Humanos , Desenvolvimento da Linguagem , Transtornos Mentais/psicologia , Língua de Sinais
18.
Br J Dermatol ; 110(5): 601-6, 1984 May.
Artigo em Inglês | MEDLINE | ID: mdl-6722029

RESUMO

Human sebaceous glands were studied by electron microscopy using lanthanum tracer and freeze-fracture methods. Gap junctions but no tight junctions were found. It is suggested that the essential permeability barrier may be formed by the secreted sebaceous neutral lipid.


Assuntos
Junções Intercelulares/ultraestrutura , Glândulas Sebáceas/ultraestrutura , Adulto , Idoso , Permeabilidade da Membrana Celular , Técnica de Fratura por Congelamento , Humanos , Lantânio , Masculino , Microscopia Eletrônica , Glândulas Sebáceas/fisiologia
19.
Cell Tissue Res ; 190(1): 115-21, 1978 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-688331

RESUMO

An examination of human seabaceous glands by transmission electron microscopy has revealed the presence of gap junctions. The junctions are found in abundance between differentiating cells, and annular forms are also seen. The possible significance of this new finding is briefly discussed.


Assuntos
Junções Intercelulares/ultraestrutura , Glândulas Sebáceas/ultraestrutura , Diferenciação Celular , Humanos
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