Decolouration of the lens pigment in senile nuclear cataract

Human cataract lens proteins can be bleached by exposure to sodium borohydride (NaBH4), sodium cyanoborohydride (NaCNBH3), or hydrogen peroxide (H2O2). The decolouration resulting from these treatments could be monitored by a change in absorbance at 350 nm. At pH 12 the magnitude of the absorbance change increased in proportion with the severity of the nuclear cataract in the case of NaBH4 and H2O2 treatments, but not in the case of NaCNBH3 treatment. The rate of change in absorbance at 350 nm following exposure to the different reagents was used to evaluate three model systems for senile nuclear cataract. These model systems utilized calf lens proteins which had been tanned by exposure either to 3-hydroxyanthranilic acid, dopa/tyrosinase, or ultraviolet light.     

Detection of haematoporphyrin derivative and haematoporphyrin excited states in cell environments

The photosensitiser currently used in the photodynamic therapy of cancer is haematoporphyrin derivative. Pulsed laser studies of this material and also of the "parent" molecule haematoporphyrin in polyoma-transformed fibroblast cells have now been studied. We report, for the first time, the observation of the triplet absorption of these sensitisers in cells. The corresponding triplet-triplet spectra are red shifted compared to aqueous buffer, lambda(max) 420 nm shifts to 460 nm. We also report our failure to observe singlet oxygen from the cells even though the triplet state can be seen to interact with the oxygen and even though singlet oxygen can be readily detected with the same sensitisers bound to serum albumin.     

Lipopolysaccharide augments IgG and IgE responses of mice to the latex allergen Hev b 5

Background: LPS is a common contaminant in the health care environment and in latex examination gloves. Objective: We sought to investigate the role of LPS in enhancing the immune responses of mice to inhaled latex allergen. Methods: As our model allergen, we used a fusion protein containing the potent latex allergen Hev b 5. BALB/c mice were lightly anesthetized and given repeated intranasal doses of saline, LPS, and/or Hev b 5. The doses were given in 2 courses separated by a 6-week period, with the first course consisting of 6 doses and the second consisting of 3 doses. Results: After the first set of immunizations, mice given Hev b 5 alone had no detectable IgG1 or IgE responses to Hev b 5, whereas mice given the antigen along with LPS had significant responses (IgG1, 0.73 U ± 0.05; IgE, 0.88 U ± 0.2). No enhancement of specific IgG2a was observed. A stimulatory effect of LPS on all 3 immunoglobulin types was apparent after the second course. Lymphocytes from mice immunized with LPS and Hev b 5 had increased proliferation to Hev b 5 and its fusion partner. Conclusions: LPS may be an important immunoadjuvant for the development of allergic reactions to latex protein allergens. (J Allergy Clin Immunol 199;102:977-83.)     

Glucoindole alkaloids from Ophiorrhiza acuminata

Extraction of Ophiorrhiza acuminata L. leaves has yielded harman, lyalosidic acid, and palicoside whose structures were verified by 2D-NMR spectroscopy and by comparison with literature data.     

Age-related changes in the kinetics of water transport in normal human lenses

The aim of this work was to study blink frequency changes and levels of ocular discomfort during work at a video display terminal, and the effects on these parameters of augmented or reduced humidification of the ocular surface.Blink rate was measured from recordings of the electrical signal evoked by the contraction of the orbicularis oculi muscle. Blink rate and interblink intervals were analyzed at rest and during performance of a task with a computer (playing a card game) for 10 or 30 min in steady environmental conditions and during application of a continuous stream of air to the face. In two separate sessions, the effect of pretreatment with humidifying ocular solutions of different elastoviscosity (balanced salt solution or elastoviscous 0.1% Hylan A solution) was assayed. At the end of each experimental period, the subjects marked the level of ocular discomfort experienced on a 0-10 cm visual analogue scale.The blink frequency at rest (12.4+/-1.2 blinks min-1) was reduced significantly (to 10.3+/-1.1 blinks min-1) by pretreatment with elastoviscous eyedrops both with and without air applied to the face. This effect was not obtained with balanced salt solution. During performance of the visual task for 10 or 30 min, basal blink rate decreased significantly, to about 40% of the control value. Neither application of an air jet on the face nor application of eye solutions of different viscosity modified this reduced blink rate.A low degree of ocular discomfort developed after performance of the visual task that was enhanced by air application to the face. This discomfort was reduced by pretreatment with ocular solutions, the elastoviscous eye solution being more efficient than the balanced salt solution. Interblink interval duration was also more regular after treatment with the elastoviscous solution.These data suggest that blink rate at rest is maintained in part by activation of sensory receptors of the cornea and conjunctiva, which are stimulated by desiccation of the ocular surface. Reduction of eye blink frequency elicited by the performance of a visual task with a computer appears to depend on central neural mechanisms that are quite independent of peripheral sensory inputs. The reduction of blink frequency consecutive to computer use was associated with a sensation of discomfort that was attenuated more effectively by elastoviscous eyedrops than by regular balanced salt solution.     

The pig as a model system for investigating the recruitment and contribution of myofibroblasts in skin healing

In the skin-healing field, porcine models are regarded as a useful analogue for human skin due to their numerous anatomical and physiological similarities. Despite the widespread use of porcine models in skin healing studies, the initial origin, recruitment and transition of fibroblasts to matrix-secreting contractile myofibroblasts are not well defined for this model. In this review, we discuss the merit of the pig as an animal for studying myofibroblast origin, as well as the challenges associated with assessing their contributions to skin healing. Although a variety of wound types (incisional, partial thickness, full thickness, burns) have been investigated in pigs in attempts to mimic diverse injuries in humans, direct comparison of human healing profiles with regards to myofibroblasts shows evident differences. Following injury in porcine models, which often employ juvenile animals, myofibroblasts are described in the developing granulation tissue at 4 days, peaking at Days 7–14, and persisting at 60 days post-wounding, although variations are evident depending on the specific pig breed. In human wounds, the presence of myofibroblasts is variable and does not correlate with the age of the wound or clinical contraction. Our comparison of porcine myofibroblast-mediated healing processes with those in humans suggests that further validation of the pig model is essential. Moreover, we identify several limitations evident in experimental design that need to be better controlled, and standardisation of methodologies would be beneficial for the comparison and interpretation of results. In particular, we discuss anatomical location of the wounds, their size and depth, as well as the healing microenvironment (wet vs. moist vs. dry) in pigs and how this could influence myofibroblast recruitment. In summary, although a widespread model used in the skin healing field, further research is required to validate pigs as a useful analogue for human healing with regards to myofibroblasts.     

Effects of gonadotropins and adenocorticotropin on plasmatic steroids of the catfish, Heteropneustes fossilis (Bloch).

The levels of some steroids in the plasma of female catfish were estimated following a single injection of porcine ACTH, ovine LH, or partially purified salmon gonadotropin (SG-G100) during the spawning and postspawning seasons. In the regressed catfish, injection of either LH or SG-G100 resulted in a three- to fourfold increase, compared to uninjected controls, in plasmatic cortisol for at least 1 hr. Injection of LH and ACTH resulted in two- and fourfold increases, respectively, of plasma cortisol levels as compared to saline-injected controls for both regressed and gravid fish. The concentration of plasma cortisol after ACTH treatment was higher than after LH or SG-G100. Gonadectomy did not influence the effect of LH on plasma cortisol concentration, and 20 min after injection, the cortisol concentration was identical to that of the intact fish. These results show that in the gravid catfish, as in the regressed ones, the increase in plasmatic cortisol after injection of LH or SG-G100 results principally from the activation of the interrenal. The concentrations of 11-deoxycortisol, 11-deoxycorticosterone, and 17α-hydroxy-20β-dihydroprogesterone were low in all samples and there was no evidence of an effect related to the injected hormone. Testosterone concentrations in the plasma of gravid fish injected with LH increased over the 1-hr sampling time and all values were higher than those recorded for saline- or ACTH-injected fish. Since the levels of cortisol and testosterone in the plasma of gravid catfish increase following gonadotropin administration, they may either singly or synergistically play a role in oocyte maturation.     

Cross-cultural ranking of IADL skills

Although causal theories of aging differ considerably across disciplines, the common denominator in published papers on the health and function of the aged is to be found in the methods section. The instrumental activities of daily living (IADL), used to determine the independence of the aged living in the community, are utilized both at a clinical and population level. While there has been a cross-disciplinary need for a scale to measure sub-populations, many scholars have been reticent to use the existing IADL items across geographical backgrounds. The results of this study, which surveys 236 physicians from 11 different cultures on the importance of individual IADL items, suggests the IADL may be useful as a universal measure of function.     

Formation of hydroxyl radicals in the human lens is related to the severity of nuclear cataract

Recent studies have identified specific hydroxylated amino acid oxidation products which strongly suggest the presence of hydroxyl radical (HO.)-damaged proteins in human cataractous lenses. In the present study, the ability of early stage (type II) and advanced (type IV) nuclear cataractous lens homogenates to catalyse HO. production in the presence of H(2)O(2)was investigated using electron paramagnetic resonance (EPR) spectroscopy with the free radical trap, 5,5-dimethyl-1-pyrroline- N -oxide (DMPO). Cataractous lens homogenates incubated with 1 m m H(2)O(2)generated a distinct HO. signal, which was significantly more intense in the nuclear region of the type IV compared to the type II lenses. The ability of individual lens nuclei and cortices to stimulate HO. production was positively correlated. The DMPO-HO. signal was competitively inhibited by ethanol, confirming that the DMPO-HO. signal was due to HO. formation and not DMPO-OOH degradation. The metal ion chelator, diethylenetriaminepentaacetic acid, also inhibited HO. formation, indicating that lenticular metal ions play a key role in HO. formation. Cataractous lens homogenates also stimulated ascorbyl radical production, further suggesting the presence of redox-active metal ions in the tissue. Analysis of lenses for total Fe and Cu (using atomic absorption spectrometry) showed that the more advanced type IV lenses tended to have higher Fe, but similar Cu, levels compared to the type II lenses. The levels of both metals were lower in non-cataractous lenses. These data support the hypothesis that transition metal-mediated HO. production may play a role in the aetiology of age-related nuclear cataract.     

Distribution of ferritin and redox-active transition metals in normal and cataractous human lenses

Previous studies have shown that lenticular levels of Fe and Cu are elevated in age-related cataract. However, it is not known if these metals are present in a state that is permissive for redox reactions that may lead to the formation of free radicals. In addition, there is little data available concerning the concentration and lenticular distribution of ferritin, the major intracellular Fe-sequestering protein, in the lens. The aim of the present work was therefore to determine the distribution of ferritin and the redox-availability of Fe and Cu in healthy and cataractous lenses. Lens ferritin distribution was assessed by ELISA and immunohistochemistry. A modified ELISA detected ferritin in an 'insoluble' lens protein fraction. Ferritin levels were not significantly different in the cortex vs nucleus of healthy lenses. In contrast, ferritin levels in the cataractous lens nuclei appeared to be 70% lower compared to the cortex. This was at least partially due to the presence of ferritin within an insoluble protein fraction of the homogenized lenses. In normal lenses, ferritin staining was most intense in the epithelium, with diffuse staining observed throughout the cortex and nucleus. The redox-availability of lenticular metals was determined using: (1) autometallography; (2) Ferene-S as a chromogenic Fe chelator; and (3) NO release from nitrosocysteine to probe for redox-active Cu. The autometallography studies showed that the cataractous lenses stained more heavily for redox-active metals in both the nucleus and cortex when compared to age-matched control lenses. Chelatable Fe was detected in homogenized control lenses after incubation with Ferene-S, with almost three-fold higher levels detected in the cataractous lenses on average. The Cu-catalysed liberation of NO from added nitrosocysteine was not demonstrated in any lens sample. When exogenous Cu (50 n M) was added to the lenses, it was rapidly chelated. The cataractous samples were approximately twice as effective at redox-inactivation of added Cu. These studies provide evidence that a chelatable pool of potentially redox-active Fe is present at increased concentrations in human cataractous lenses. In contrast, it seems that lenticular Cu may not be readily available for participation in redox reactions.