RESUMEN
Sheep's wool was used as a natural source to prepare keratin microfibril sponges for scaffolding, by disruption of the histological structure of the fibres through mild alkali treatment, followed by ultrasonication, casting and salt-leaching. The wool sponges showed highly interconnected porosity (93%) and contain intrinsic sites of cellular recognition that mimic the extracellular matrix (ECM). They displayed good thermal and water stability due to the conversion of disulphide cystine bonds into shorter monosulphide lanthionine intermolecular bonds, but significantly swelled in water, because of the high hydrophilicity and porosity, with a volume increasing up to 38%. Nevertheless, sponges were stable in water without structural changes, with a neutral pH in aqueous media, and showed excellent resilience to repeated compression stresses. According to in vitro biocompatibility assays, wool fibril sponges showed a good cell adhesion and proliferation as proved by MTT, FDA assays and SEM observations. The unique structure of the cortical cell network made by wool keratin proteins with controlled-size macro-porosity suitable for cell guesting, and nutrient feeding, provides an excellent scaffold for future tissue engineering applications.
Asunto(s)
Queratinas/química , Ingeniería de Tejidos , Andamios del Tejido/química , Lana/química , Animales , OvinosRESUMEN
Structural characteristics of keratin regenerated from water (KW) and from formic (KF) acid solutions were compared. Amino acid composition and molecular weight distribution of KW and KF samples were studied by high performance liquid chromatography (HPLC) and SDS-PAGE electrophoresis. Turbidity measurement showed that keratin dissolved in formic acid forms transparent and stable solutions and no flocculation occurs. In addition, because of its good solvation properties, studied by viscosity measurements, formic acid can be used as a co-solvent to prepare keratin-based blend solutions. Structural studies carried out by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and near infrared (NIR) suggest that formic acid stabilizes the beta-sheet structure. Thermogravimetric analysis (TGA) reveals a higher thermal stability of keratin regenerated from formic acid with respect to keratin regenerated from water.
Asunto(s)
Formiatos/química , Queratinas/química , Lana/química , Animales , Cromatografía Líquida de Alta Presión , Floculación , Estructura Secundaria de Proteína , Ovinos , Espectroscopía Infrarroja por Transformada de Fourier , Viscosidad , Difracción de Rayos XRESUMEN
OBJECTIVES: To determine frequency and type of respiratory and allergic symptoms in textile workers employed in early stages of wool processing. METHODS: A cross-sectional study was carried out in four wool textile mills. 202 subjects (n. 148 males, 54 females, mean age 38.9 yrs, SD 9.5) employed in early stages (combing, n. 138, carding, n. 64) of wool processing were examined and an environmental survey was carried out to determine the level of wool dust exposure. All subjects were submitted to clinical interview, spirometry and measurement of serum specific IgE (s-IgE) against extracts of two wool lots (Australia and New Zealand) by means of RAST. In the subjects with a positive questionnaire for allergic symptoms serum specific IgE for common pneumoallergens were measured (PHADIATOP test). RESULTS: We found higher air dust concentrations during carding operations (inspirable fraction-IF-: range 1.6-20 mg/m3; respirable fraction (RF): 0.5-6.9 mg/m3) and lower concentrations during combing (IF 0.3-0.7 mg/m3, RF 0.1-0.3 mg/m3). 70 out of 202 subjects (34.7%, n. 26 employed in carding and n. 44 in combing operations) reported work-related symptoms. Cutaneous itching was reported by 30 subjects, upper airway irritation by 24, ocular irritation by 17 and dyspnoea by 5. Globally 27 subjects (13.4%) had respiratory work-related symptoms. 12 subjects reported only seasonal respiratory symptoms not related to work. Within the group of 82 symptomatic subjects, 62 (75.6%) had serum specific IgE for common pneumoallergens. In the whole group (n. 202) mean basal FEV-1 was L 3.6, SD 0.9 (103.6% of predicted values). No significant difference was found in basal FEV-1 between carding and combing workers. No s-IgE against the two wool extracts was detectable in any of the 202 examined subjects. CONCLUSIONS: Our data show that in early stages of wool processing: 1) the overall frequency of respiratory work-related symptoms is low and does not seem to be related to the stages of processing, 2) symptoms are mainly nasal and/or ocular; 3) serum s-IgE against wool extracts are not detectable. We conclude that respiratory allergy risk in wool textile mills is low.
Asunto(s)
Hipersensibilidad/epidemiología , Enfermedades Profesionales/epidemiología , Trastornos Respiratorios/epidemiología , Lana , Adulto , Animales , Recolección de Datos , Femenino , Humanos , Italia , MasculinoRESUMEN
Locomotor strategies used before the acquisition of independent walking were studied in 424 infants. 270 were survivors of neonatal intensive care (the index group); the other 154 (controls) had had no perintal complications. Five forms of locomotion were distinguished: crawling on hands and knees, creeping on the stomach, bottom-shuffling, other, and none before independent walking. Crawling was the most common form of locomotion in both groups. A higher percentage in the index group were late crawlers (greater than 10 months), but similar proportions in both groups were bottom-shufflers or simply stood up and walked. One of the most important factors influencing locomotor strategies was asymmetry. Analysis of the influence of locomotor strategies on psychomotor and linguistic outcome up to five years showed no significant relationships within the index group. However, within the control group, infants who crawled had a statistically greater incidence of later motor delay, which is in contrast to the findings of other studies.