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1.
Vet Pathol ; 60(2): 185-189, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36541627

RESUMEN

Sebaceous carcinomas of the human ocular adnexa commonly exhibit pagetoid spread, mutations in tumor-suppressor genes, and protooncogene copy number gain. Sebaceous carcinomas are rarely reported in other species, and while the Meibomian gland (MG) represents the most common ocular adnexal structure of the canine eyelid to develop neoplasia, most are clinically and histologically benign. The objective of this study was to compare molecular features of canine MG carcinomas and adenomas. Two retrospectively identified MG carcinomas were subject to immunohistochemistry and qPCR. When compared with normal glands, MYC was upregulated in benign and malignant MG neoplasms. Aberrant p53 expression was restricted to the nuclei of intraepithelial neoplastic cells in MG carcinomas. Adipophilin expression was diminished in MG neoplasms compared with the normal MG. Our findings, if confirmed in a larger cohort of cases, could suggest that MG oncogenesis in a dog may exhibit similar molecular features as their human counterparts.


Asunto(s)
Adenoma , Carcinoma Basocelular , Enfermedades de los Perros , Neoplasias de las Glándulas Sebáceas , Neoplasias Cutáneas , Humanos , Perros , Animales , Glándulas Tarsales/metabolismo , Glándulas Tarsales/patología , Proteína p53 Supresora de Tumor , Estudios Retrospectivos , Neoplasias de las Glándulas Sebáceas/química , Neoplasias de las Glándulas Sebáceas/metabolismo , Neoplasias de las Glándulas Sebáceas/patología , Neoplasias de las Glándulas Sebáceas/veterinaria , Neoplasias Cutáneas/veterinaria , Carcinoma Basocelular/veterinaria , Transformación Celular Neoplásica , Adenoma/patología , Adenoma/veterinaria , Mutación
2.
Ann Trop Paediatr ; 31(4): 321-30, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22041466

RESUMEN

BACKGROUND: Anaemia is a significant global public health problem in developing countries with adverse health effects on young children. Household food insecurity, which reflects a household's access, availability and utilisation of food, has not been well characterised in relation to anaemia in children. OBJECTIVE: To examine the relationship of household food insecurity with anaemia (Hb <11 g/dl) in children. METHODS: In a cross-sectional study of 4940 rural households participating in the Indonesian Nutrition Surveillance System, household food insecurity was measured using a modified 9-item food security questionnaire and related to anaemia in children aged 6-59 months. RESULTS: The proportion of households with an anaemic child was 56·6%. In households with and without anaemic children, the mean (SD) food insecurity score was 1·82 (1·72) vs 1·55 (1·54) (p<0·0001), respectively. In a multivariate logistic regression model, food insecurity score was related to anaemia in children (odds ratio 0·77, 95% confidence interval 0·63-0·95, p=0·01) when the highest quintile of food insecurity score was compared with the lowest quintile, adjusting for potential confounders. CONCLUSION: A higher household food insecurity score is associated with greater prevalence of anaemia in children in rural families in Indonesia.


Asunto(s)
Anemia/epidemiología , Dieta/efectos adversos , Abastecimiento de Alimentos/estadística & datos numéricos , Estado Nutricional , Preescolar , Estudios Transversales , Composición Familiar , Femenino , Humanos , Indonesia , Lactante , Masculino , Prevalencia , Población Rural , Encuestas y Cuestionarios
3.
Eur J Clin Nutr ; 64(12): 1393-8, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20842167

RESUMEN

BACKGROUND/OBJECTIVES: Dietary diversity is associated with overall quality and nutrient adequacy of the diet in low-income countries. We determined the association between dietary diversity and stunting among children aged 6-59 months in rural Bangladesh. SUBJECTS/METHODS: In total, 165 111 under-fives who participated in the National Surveillance Project in 2003-2005 were included in the analysis. Dietary diversity score (DDS) was constructed through the summation of the number of days each of the nine food groups was consumed in the previous week. The association between stunting and DDS was determined adjusting for confounders using logistic regression models. All analyses were performed separately for children aged 6-11, 12-23 and 24-59 months. RESULTS: One-half of the children were stunted. In multivariate analyses, compared with low DDS, high dietary diversity was associated with a 15, 26 and 31% reduced odds of being stunted among children aged 6-11, 12-23 and 24-59 months, respectively, after adjusting for all potential confounders (odds ratio (OR)=0.85, 95% confidence interval (CI): 0.76-0.94; OR=0.74, 95% CI: 0.69-0.79; OR=0.69, 95% CI: 0.66-0.73). In all groups, children who were still breastfed were more likely to have limited diversity (OR=1.88, 95% CI: 1.32-2.67; OR=1.71, 95% CI: 1.52-1.92; OR=1.15, 95% CI: 1.11-1.19). Those having diarrhea in the past week and coming from families with low socioeconomic status were more likely to have decreased diversity (P<0.05). CONCLUSIONS: Reduced dietary diversity is a strong predictor of stunting in rural Bangladesh. The inclusion of a variety of food groups into complementary foods may be essential to improve child nutritional status.


Asunto(s)
Fenómenos Fisiológicos Nutricionales Infantiles , Dieta , Trastornos del Crecimiento/epidemiología , Estado Nutricional , Pobreza , Población Rural , Antropometría , Bangladesh/epidemiología , Preescolar , Femenino , Alimentos/economía , Humanos , Lactante , Modelos Logísticos , Masculino , Análisis Multivariante , Oportunidad Relativa
4.
J Dairy Sci ; 86(6): 2145-53, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12836951

RESUMEN

Intake of colostrum by neonatal calves and early transition to calf starter are two important factors in successful calf programs. Thirty-one Holstein calves were used to determine health and performance of calves that were 1) allowed to remain with their dams for 3 d and suckle (suckled calves) or were removed from their dams and fed colostrum only by bottle (bottle calves); and were 2) fed ground, pelleted, or textured starters, formulated to be isonitrogenous. Bottle calves were removed from their dams at birth, fed 2.84 L of colostrum, placed in individual hutches, and fed 1.89 L of colostrum 12 h after the first feeding. Suckled calves were removed from their dams after 3 d and placed in individual hutches. Once calves were housed in hutches, they were fed 2 L of whole milk twice daily and were provided starters and water beginning on d 3. Calves were weighed at birth and weekly for 6 wk. Blood samples were obtained at birth, 24 h, and weekly for serum protein determination. Starter intake, fecal scores, and electrolyte treatments were recorded daily. Weaning began when calves had consumed 0.68 kg starter for 2 d consecutively. There were no differences in treatment means between suckled and bottle calves for total gain, grain consumption, days with fecal scores >2, or electrolyte treatments per calf. Average days to weaning was greater for bottle calves compared with suckled calves. Mean serum protein concentration at 24 h was greater for bottle (6.0 g/dl) compared with suckled calves (5.8 g/dl) and only 2 of 15 bottle calves had serum protein concentrations <5.0 g/dl compared with 6 of 16 suckled calves. For starter treatments, calves fed textured starter consumed more total grain, were weaned earlier, and weighed more at 6 wk of age than calves fed pelleted starter. Based on 24-h serum protein concentrations, transfer of passive immunity was greater for bottle calves compared with suckled calves.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Animales Recién Nacidos/fisiología , Bovinos/fisiología , Calostro , Dieta , Estado de Salud , Animales , Animales Recién Nacidos/inmunología , Animales Lactantes , Proteínas Sanguíneas/análisis , Peso Corporal , Bovinos/inmunología , Grano Comestible , Inmunidad Materno-Adquirida , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Destete
5.
J Trauma ; 50(6): 1008-14, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11426113

RESUMEN

BACKGROUND: Pin tract infection is a common complication of external fixation. An antiinfective external fixator pin might help to reduce the incidence of pin tract infection and improve pin fixation. METHODS: Stainless steel and titanium external fixator pins, with and without a lipid stabilized hydroxyapatite/chlorhexidine coating, were evaluated in a goat model. Two pins contaminated with an identifiable Staphylococcus aureus strain were inserted into each tibia of 12 goats. The pin sites were examined daily. On day 14, the animals were killed, and the pin tips cultured. Insertion and extraction torques were measured. RESULTS: Infection developed in 100% of uncoated pins, whereas coated pins demonstrated 4.2% infected, 12.5% colonized, and the remainder, 83.3%, had no growth (p < 0.01). Pin coating decreased the percent loss of fixation torque over uncoated pins (p = 0.04). CONCLUSION: These results demonstrate that the lipid stabilized hydroxyapatite/chlorhexidine coating was successful in decreasing infection and improving fixation of external fixator pins.


Asunto(s)
Antiinfecciosos Locales/farmacología , Clavos Ortopédicos , Clorhexidina/farmacología , Durapatita/farmacología , Fijadores Externos , Fijación de Fractura/instrumentación , Infecciones Estafilocócicas/prevención & control , Fracturas de la Tibia/terapia , Animales , Distribución de Chi-Cuadrado , Materiales Biocompatibles Revestidos , Remoción de Dispositivos , Modelos Animales de Enfermedad , Cabras , Masculino , Acero Inoxidable , Estadísticas no Paramétricas , Titanio , Torque
6.
Matern Child Health J ; 4(3): 163-9, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11097503

RESUMEN

OBJECTIVES: This article reviews the history of the measurement of unwanted and unintended pregnancy in fertility surveys in the United States. These concepts were developed in order to help explain trends and differences in birth rates in the United States. BACKGROUND: Unwanted fertility was first measured systematically in a survey in Indianapolis in 1941. The first national surveys to measure the concept of unwanted fertility were the 1955 and 1960 Growth of American Families Studies. All three of these surveys were limited to married women. In the 1965 National Fertility Survey, the concept of mistimed births was introduced. The 1973, 1976, 1982, and 1988 National Survey of Family Growth (NSFG) continued to measure trends in unwanted and mistimed fertility, while expanding the population interviewed, from currently married to all marital statuses. The 1993 and 2001 NSFGs have enriched the data on wantedness with new measures of ambivalence and the strength of feelings about having children. CONCLUSION: Measures of unwanted fertility, while imperfect, have been useful and will continue to be improved in the future.


Asunto(s)
Tasa de Natalidad , Fertilidad , Embarazo , Adolescente , Adulto , Estudios de Cohortes , Anticoncepción , Recolección de Datos , Composición Familiar , Servicios de Planificación Familiar , Femenino , Humanos , Ilegitimidad , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Embarazo/psicología , Embarazo/estadística & datos numéricos , Embarazo no Deseado , Muestreo , Factores Socioeconómicos , Estados Unidos
7.
J Biomed Mater Res ; 53(4): 400-7, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10898881

RESUMEN

The surface-induced mineralization (SIM) technique was used to produce hydroxyapatite (HAP) coatings on external fixation pins with the antimicrobial agent, chlorhexidine, incorporated within the coating. The SIM process involved surface modification of the substrate with organic functional groups followed by immersion in aqueous supersaturated calcium phosphate solutions. X-ray diffraction spectra confirmed that hydroxyapatite coatings were formed. Chlorhexidine was incorporated into the coating by placing the substrate into various chlorhexidine solutions in between mineralization cycles. Total uptake was measured by dissolution of the coating into a 0.1 M nitric acid solution and measuring the chlorhexidine concentration using UV spectroscopy at 251 nm. Release rates were measured by submersion of coated substrates into saline solutions and measuring chlorhexidine UV absorbency at 231 nm as a function of time. Results show an initial rapid release followed by a period of slower sustained release. The anti-microbial efficacy of the HAP-chlorhexidine coatings was evaluated in vitro using a Staphylococcus aureus cell culture. Initial results show a large "inhibition zone" formed around the chlorhexidine/HAP coating vs. coatings with HAP only. This preliminary work clearly demonstrates that SIM HAP coatings have great potential to locally deliver antimicrobial agents such as chlorhexidine at implantation sites, which may greatly reduce the incidence of pin tract infection that occurs in external fixation.


Asunto(s)
Antiinfecciosos Locales/administración & dosificación , Sustitutos de Huesos , Calcificación Fisiológica , Clorhexidina/administración & dosificación , Durapatita , Fijación de Fractura , Sistemas de Liberación de Medicamentos , Humanos
8.
Calcif Tissue Int ; 64(6): 516-21, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10341024

RESUMEN

Acidic proteins found in mineralized tissues act as nature's crystal engineers, where they play a key role in promoting or inhibiting the growth of minerals such as hydroxyapatite and calcium oxalate. Despite their importance in such fundamental physiological processes as bone and tooth formation, however, there is remarkably little known of the protein structure-function relationships that govern crystal recognition. We have taken a model system approach to elucidate some of the relationships between protein surface chemistry and secondary crystal growth of biological minerals. We show here that the distribution of electrostatic surface charge on our model protein, Protein G, determined whether the secondary growth of calcium oxalate, the principal mineral phase of kidney stones, was promoted or inhibited when the proteins were preadsorbed at low and equivalent surface coverages of <10%. The native Protein G, which contains 10 surface carboxylates, increased the rate of calcium oxalate growth from aqueous solution under constant composition conditions up to 97%, whereas a site-directed mutant with six of the surface charges removed inhibited the growth rate by 60%. The adsorption isotherms of both proteins were determined and suggested that the differences in electrostatic surface properties also lead to differences in protein orientation on the crystal surface. These results demonstrate that differences in electrostatic surface potential of proteins can directly determine whether secondary calcium oxalate growth is promoted or inhibited, and a model is proposed that suggests the distribution of carboxylate residues determines the interrelated binding orientation and exposed surface chemistry of the adsorbed Protein G.


Asunto(s)
Oxalato de Calcio/química , Proteínas del Tejido Nervioso/química , Secuencia de Aminoácidos , Calcificación Fisiológica/fisiología , Cristalización , Electroquímica , Escherichia coli , Modelos Estructurales , Datos de Secuencia Molecular , Electricidad Estática , Propiedades de Superficie , Termodinámica
9.
Proc Natl Acad Sci U S A ; 95(21): 12083-7, 1998 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-9770443

RESUMEN

Proteins play an important role in the biological mechanisms controlling hard tissue development, but the details of molecular recognition at inorganic crystal interfaces remain poorly characterized. We have applied a recently developed homonuclear dipolar recoupling solid-state NMR technique, dipolar recoupling with a windowless sequence (DRAWS), to directly probe the conformation of an acidic peptide adsorbed to hydroxyapatite (HAP) crystals. The phosphorylated hexapeptide, DpSpSEEK (N6, where pS denotes phosphorylated serine), was derived from the N terminus of the salivary protein statherin. Constant-composition kinetic characterization demonstrated that, like the native statherin, this peptide inhibits the growth of HAP seed crystals when preadsorbed to the crystal surface. The DRAWS technique was used to measure the internuclear distance between two 13C labels at the carbonyl positions of the adjacent phosphoserine residues. Dipolar dephasing measured at short mixing times yielded a mean separation distance of 3.2 +/- 0.1 A. Data obtained by using longer mixing times suggest a broad distribution of conformations about this average distance. Using a more complex model with discrete alpha-helical and extended conformations did not yield a better fit to the data and was not consistent with chemical shift analysis. These results suggest that the peptide is predominantly in an extended conformation rather than an alpha-helical state on the HAP surface. Solid-state NMR approaches can thus be used to determine directly the conformation of biologically relevant peptides on HAP surfaces. A better understanding of peptide and protein conformation on biomineral surfaces may provide design principles useful for the modification of orthopedic and dental implants with coatings and biological growth factors that are designed to enhance biocompatibility with surrounding tissue.


Asunto(s)
Durapatita/química , Péptidos/química , Secuencia de Aminoácidos , Cristalización , Cinética , Espectroscopía de Resonancia Magnética , Conformación Proteica , Proteínas y Péptidos Salivales/química , Propiedades de Superficie
10.
Biochim Biophys Acta ; 1380(1): 31-45, 1998 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-9545525

RESUMEN

Oriented calcium oxalate crystals have been grown beneath phospholipid monolayers at the air-solution interface from supersaturated calcium oxalate solutions. Mature calcium oxalate crystals grown beneath zwitterionic dipalmitoylphosphatidylcholine (DPPC) monolayers exhibit the characteristic morphology of calcium oxalate monohydrate (COM) crystals with the elongated (101) crystal face preferentially oriented parallel to the plane of the monolayer. Calcium oxalate crystals grown beneath negatively-charged dimyristoylphosphatidylserine (DMPS) monolayers also show a preferential orientation with respect to the monolayer; they do not, however, exhibit the characteristic COM morphology. Raman spectroscopy strongly suggests that the crystals grown beneath either DPPC or DMPS monolayers are the monohydrate phase of calcium oxalate; therefore, differences in crystal morphology are not due to differences in the crystalline phase. Dimyristoylphosphatidylethanolamine (DMPE), dimyristoylphosphatidic acid (DMPA), eicosanoic acid (C20), and eicosanol (C20-OH) monolayers have also been studied to help elucidate the mechanisms of interaction between the lipid monolayers and the calcium oxalate crystals. We discuss the roles of lattice matching, hydrogen bonding, stereochemistry and electrostatics on crystal orientation and morphology.


Asunto(s)
Oxalato de Calcio/química , Fosfolípidos/química , 1,2-Dipalmitoilfosfatidilcolina/química , Calcificación Fisiológica , Cristalización , Enlace de Hidrógeno , Técnicas In Vitro , Modelos Químicos , Fosfatidilserinas/química , Espectrometría Raman , Electricidad Estática , Estereoisomerismo
11.
J Biomed Mater Res ; 34(4): 539-43, 1997 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-9054537

RESUMEN

The purpose of this pilot study was to evaluate surface-induced mineralization (SIM) as a potential technique to apply ceramic coatings to metal orthopaedic implants. Cylindrical titanium porous-coated implants were either coated by SIM or plasma-spray (PLS) techniques with calcium phosphate, or left uncoated (CTL). The implants were bilaterally implanted into the intramedullary canal of the proximal femur of 24 adult New Zealand white rabbits segregated into the following groups: PLS/CTL, SIM/CTL, and SIM/PLS. After 6 weeks in vivo, biomechanical and histologic evaluations were completed. Biomechanically, SIM had consistently greater mechanical interlock than PLS implants. However, CTL implants had greater mechanical interlock than both PLS and SIM. The small sample size prevented statistical evaluation and definitive biomechanical conclusions. Histologically, SIM and PLS had significantly greater ingrowth than CTL implants (p < 0.05). The SIM coating technique produced similar ingrowth characteristics as standard PLS coatings, yet may prevent osteolysis by providing a stronger, more reliable, covalent bond between the ceramic and metal.


Asunto(s)
Fosfatos de Calcio/química , Prótesis e Implantes , Titanio/química , Aleaciones/química , Animales , Fenómenos Biomecánicos , Desarrollo Óseo/fisiología , Huesos/citología , Hidroxiapatitas/química , Ensayo de Materiales , Porosidad , Conejos , Propiedades de Superficie
12.
J Biomed Mater Res ; 32(1): 111-8, 1996 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8864879

RESUMEN

Calcium phosphate coatings were nucleated and grown from aqueous solution onto titanium metal substrates via surface-induced mineralization (SIM) processing techniques. This process is based on the observation that in nature organisms use biopolymers to produce ceramic composites, such as teeth, bones, and shells. The SIM process involves modification of a surface to introduce surface functionalization followed by immersion in aqueous supersaturated calcium phosphate solutions. This low-temperature process (< 100 degrees C) has advantages over conventional methods of calcium phosphate deposition in that uniform coatings are produced onto complex-shaped and/or microporous samples. Additionally, because it is a low-temperature process, control of the phase and crystallinity of the deposited material can be maintained.


Asunto(s)
Materiales Biocompatibles , Calcificación Fisiológica , Fosfatos de Calcio , Prótesis e Implantes , Titanio
13.
Med Sci Law ; 34(2): 155-60, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8028491

RESUMEN

Procedures relating to Insanity and Fitness to Plead are reviewed with special emphasis on the problems encountered with previous legislation. The introduction of the new Criminal Procedure (Insanity and Unfitness to Plead) Act 1991, on 1 January 1992, offered greater discretion in the disposal of these defendants, but fell short of many of the recommendations made by those advocating reform. As yet, too few cases have passed through the courts to highlight particular deficiencies in the unreformed parts of the Act, but the benefits are already apparent. Finally, some of the potential pitfalls of supervision and treatment orders and other disposals are discussed and an insanity case, dealt with under the new legislation, is presented.


Asunto(s)
Defensa por Insania , Adulto , Humanos , Masculino , Reino Unido
14.
Science ; 264(5155): 48-55, 1994 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-17778133

RESUMEN

Processing routes have been developed for the production of thin ceramic films through precipitation from aqueous solutions. The techniques are based on crystal nucleation and growth onto functionalized interfaces. Surface functionalization routes have been developed by the mimicking of schemes used by organisms to produce complex ceramic composites such as teeth, bones, and shells. High-quality, dense polycrystalline films of oxides, hydroxides, and sulfides have now been prepared from "biomimetic" synthesis techniques. Ceramic films can be synthesized on plastics and other materials at temperatures below 100 degrees C. As a low-temperature process in which water rather than organic solvents is used, this synthesis is environmentally benign. Nanocrystalline ceramics can be produced, sometimes with preferred crystallite orientation. The direct deposition of high-resolution patterned films has also been demonstrated. The process is well suited to the production of organic-inorganic composites.

15.
Scanning Microsc ; 7(1): 423-9, 1993 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8316812

RESUMEN

A physical chemical approach was used to study calcium oxalate monohydrate (COM) nucleation and growth on various organic interfaces. Self-assembling monolayers (SAMs), containing derivatized organic functional groups, were designed to mimic various amino acid residues present in both urine and stone matrix macromolecules. Derivatized surfaces include SAMs with terminal methyl, bromo, imidazole, and thiazolidine-carboxylic acid functional groups. Pronounced differences in COM deposition were observed for the various interfaces with the imidazole and thiazolidine surfaces having the greatest effect and the methyl and bromo groups having little or no nucleating potential.


Asunto(s)
Oxalato de Calcio/química , Minerales/química , Cristalización , Microscopía Electrónica de Rastreo , Modelos Químicos
17.
Am J Kidney Dis ; 17(4): 392-5, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2008905

RESUMEN

The physical chemical approach to the investigation of the calcium oxalate (CaOx) crystallization and urolith formation is the systematic examination of the various aspects of mineral precipitation and growth in pure solution, in the presence of individual urinary components, and in whole urine media. Recent experimental studies have indicated that while small urinary ions such as citrate, magnesium, and phosphocitrate retard the mineralization rate of CaOx, urinary macromolecules may act either as inhibitors of growth or promoters of nucleation. Some CaOx mineralization inhibitors have also been found to influence the growth mechanism of the phase and its flocculation properties. Therefore, urinary macromolecules that are adsorbed on the mineralizing crystals and incorporated into the developing stone may play a significant role in urolithiasis.


Asunto(s)
Oxalato de Calcio/química , Oxalato de Calcio/metabolismo , Fenómenos Químicos , Química Física , Cristalización , Humanos , Cálculos Renales/química , Cálculos Renales/metabolismo
18.
J Acquir Immune Defic Syndr (1988) ; 4(11): 1133-40, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1753341

RESUMEN

Using data from the National Survey of Family Growth, we observe that large numbers of American women say that they are responding to the rising danger of AIDS and other sexually transmitted diseases. Among the changes reported in the 1988 National Survey of Family Growth are use of condoms, sexual relations with fewer partners, reduced frequency of sexual intercourse, changes in specific sexual activities, and avoidance of sex with unknown men, bisexual men, and intravenous drug users. Interviews with a sample of the 51 million sexually active women aged 15-44 in the United States show that 28% report either that they have adopted less hazardous sexual practices or that their partners have used condoms to prevent disease. Among women exposed to higher risk of disease, the response is even greater: among unmarried women with five or more lifetime partners, 65% report modified behavior or condom use. Most of these changes occurred after the women heard of AIDS. However, there are still many women who report doing nothing to protect themselves against infection despite sexual and contraceptive behavior that appears to put them at high risk.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/psicología , Conducta Sexual , Enfermedades de Transmisión Sexual/psicología , Síndrome de Inmunodeficiencia Adquirida/prevención & control , Adolescente , Adulto , Femenino , Humanos , Factores de Riesgo , Enfermedades de Transmisión Sexual/prevención & control , Estados Unidos
19.
Calcif Tissue Int ; 45(2): 122-8, 1989 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-2476205

RESUMEN

Polyelectrolytes and protein molecules appear to be able to act not only as crystallization inhibitors when present in solution, but also as promoters of crystal growth when immobilized onto surfaces. Because this is especially relevant for systems in which heterogeneous nucleation can occur, the influence of poly-L-glutamic (PGlu) acid, poly-L-aspartic (PAsp) acid, and human serum albumin (HSA) on the nucleation and growth inhibition of calcium oxalate monohydrate (COM) was studied using the Constant Composition (CC) kinetics technique. The overgrowth of COM on hydroxyapatite (HAP) seed crystals pretreated with HSA was also investigated. Pronounced differences in inhibiting and nucleating potential were found for the various additives. HSA, a relatively poor growth inhibitor when present in solution, was found to nucleate very regular, hexagonal COM crystals when immobilized on a surface and to enhance the overgrowth of COM when adsorbed on HAP surfaces.


Asunto(s)
Oxalato de Calcio/antagonistas & inhibidores , Péptidos/farmacología , Ácido Poliglutámico/farmacología , Albúmina Sérica/farmacología , Cristalización , Humanos , Cinética , Microscopía Electrónica de Rastreo
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