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Selected AbstractsEffect of solute lipophilicity on penetration through canine skinAUSTRALIAN VETERINARY JOURNAL, Issue 12 2003PC MILLS Objective To investigate the effect of lipophilicity on the percutaneous penetration of a homologous series of alcohols through canine skin Design Skin harvested from Greyhound thorax was placed in Franz-type diffusion cells and the in vitro passage of radio-labelled (14C) alcohols (ethanol, butanol, hexanol and octanol (Log P 0.19 - 3.0)) through separate skin sections was measured in replicates of five. Permeability coefficient (kP, cm/h), maximum flux (Jmax, mol/cm2/h) and residue remaining within the skin were determined. Results The kP increased with increasing lipophilicity (6.2 times 10 -4± 1.6 times 10 -4 cm/h for ethanol to 1.8 times 10 -2± 3.6 times 10 -3 cm/h for octanol). Alcohol residues remaining within each skin sample followed a similar pattern. An exponential decrease in Jmax with increasing lipophilicity was observed. Conclusion Changes in canine skin permeability occur with increasing alcohol lipophilicity. This finding has practical consequences for the design of topical formulations and optimisation of drug delivery through animal skin. [source] 2434: Alterations of the lid wiper zone in ocular surface diseaseACTA OPHTHALMOLOGICA, Issue 2010J NEPP Purpose The marginal part of the tarsal conjunctiva forms a lid wiper structure that wipes the ocular surface and distributes the tear film during the blink. It was attempted to investigate whether this region of the upper and lower lid shows specific changes in several kinds of ocular surface diseases. Methods 44 eyes of patients from the outdoor department of the university eye clinic Vienna were observed by slit lamp investigation of the ocular surface, vital staining with fluorescein and lissamin green. It was focused on evaluation of the tarsal conjunctiva including the lid margin and the wiper. Vessel dilatation, teleangiectatic changes and vital staining were each designed in three stages. The patients suffered from inflammation or affections of the lid, the conjunctiva and the cornea including chemical burns, graft versus host disease and injuries Results Compared to normal eyes dilatation of vessels and staining was observed more in patents with inflammations but although in serious affections like chemical burn or injuries. Even in corneal affections changes of vessels were observed. Conclusion Changes of the wiper can be observed in several diseases of the ocular surface and may be a sign of strain in this region. [source] Activity of corneal nociceptive nerve fibers during allergic challenge of the ocular surfaceACTA OPHTHALMOLOGICA, Issue 2009J GALLAR Purpose The aim of this work was to study in vitro the spontaneous and stimulus-evoked electrical activity of corneal nociceptive nerve fibers during acute allergic inflammation of the ocular surface induced in the guinea-pig. Methods Animals received i.p. 10% ovalbumin (OVA). 14 days later, a 10µl drop of OVA was applied topically to each eye. Blinking and scratching movements directed to the eye were measured during 10 min, and ocular symptoms (edema and hyperemia) and tear rate were measured. Animals were killed afterwards and both eyes were immediately excised and mounted in a superfused (32°C) recording chamber. Electrical activity of corneal sensory receptors was recorded from nerve filaments dissected from the ciliary nerves. Mechanical (calibrated von Frey hairs), thermal (bath solution temperature down to 20°C or up to 52°C), and chemical stimulation (30s-pulses of 98%CO2) were performed. Spontaneous (SA) and stimulus-evoked activity were analyzed. Results After the allergic challenge, eye-scratching behavior was present in 4 out of 15 animals and blinking movements increased from 1±0.05 to 26±5. Tearing also increased compared to control (33±3 vs. 5±1 mm). Compared to naive eyes, proportion of nociceptors with SA (17% vs. 5%) and spontaneous discharge rate (0.13±0.07 vs. 0.01±0.01 imp/s) were increased. Mechanical threshold of mechano-nociceptive units decreased significantly (0.37±0.05 vs. 0.89±0.13 mN). Chemosensitivity of polymodal nociceptors was slightly increased (1.87±0.42 vs. 1.34±0.23 imp/s). Conclusion Changes in corneal sensory nerve activity observed acutely after allergic challenge of the eye surface may constitute the basis of itching and discomfort sensations, and hypersensitivity observed in allergic patients. [source] Persistence of drug use during imprisonment: relationship of drug type, recency of use and severity of dependence to use of heroin, cocaine and amphetamine in prisonADDICTION, Issue 8 2006John Strang ABSTRACT Aim To investigate the persistence of use of heroin, cocaine and amphetamine drugs during imprisonment, and to identify factors associated with increased levels of persistence. Design The use of heroin, cocaine and amphetamine by current prison inmates has been examined and, in particular, the relationship between drug use within prison and the type of drug used prior to imprisonment, recency of use and severity of dependence., Setting and participants A randomly selected sample of 1009 adult male prisoners in 13 prisons in England and Wales during 1994/95; structured confidential interviews conducted by independent research staff. Enquiry about prior use of heroin, cocaine or amphetamine focused on three time-periods (ever, last year and last month pre-prison) and the use of these drugs during the first month of imprisonment. Findings A total of 557 (55%) of the 1009 prisoners had used previously one of the three drugs selected for study: 58% had used heroin, 69% cocaine and 75% amphetamine. More than half (59%; 327/557) had used these drugs in the month before the current imprisonment. Drug use in prisons was most likely to occur among those who had used in the month prior to imprisonment. The persistence of heroin use in prison occurred more frequently (70%) than use of cocaine (20%) or amphetamine (15%). Of those using heroin pre-imprisonment, 67% considered they were dependent, compared to 15% and 22%, respectively, for cocaine and amphetamine users. Conclusions Changes in the drug-taking behaviour of drug users after imprisonment vary according to the type of drug being taken. Prisoners were much more likely to continue to use heroin than either cocaine or amphetamines while in prison. Heroin was most likely to be used by those who had been using heroin during the immediate pre-imprisonment period, and particularly by the two-thirds of heroin users who considered themselves dependent. In view of the high prevalence of prior use of these drugs by individuals currently imprisoned, continuing attention is required to study of their behaviour and of the impact of interventions that may be introduced during or following their incarceration. [source] Fire regimes and forest changes in mid and upper montane forests of the southern Cascades, Lassen Volcanic National Park, California, U.S.A.JOURNAL OF BIOGEOGRAPHY, Issue 1 2000A. H. Taylor Abstract Aim Spatial and temporal variation in fire regime parameters and forest structure were assessed. Location A 2630-ha area of mid- and upper montane forest in Lassen Volcanic National Park (LVNP). Methods Two hypotheses were tested concerned with fire-vegetation relationships in southern Cascades forests: (1) fire regime parameters (return interval, season of burn, fire size, rotation period) vary by forest dominant, elevation and slope aspect; and (2) fire exclusion since 1905 has caused forest structural and compositional changes in both mid- and upper montane forests. The implications of the study for national park management are also discussed. Results Fire regime parameters varied by forest compositional group and elevation in LVNP. Median composite and point fire return intervals were shorter in low elevation Jeffrey pine (Pinus jeffreyi) (JP) (4,6 years, 16 years) and Jeffrey pine,white fir (Abies concolor) (JP-WF) (5,10 years, 22 years) and longer in high elevation red fir (Abies magnifica), western white pine (Pinus monticola) (RF-WWP) forests (9,27 years, 70 years). Median fire return intervals were also shorter on east-facing (6,9 years, 16.3 years) and longer on south- (11 years, 32.5 years) and west-facing slopes (22,28 years, 54-years) in all forests and in each forest composition group. Spatial patterns in fire rotation length were the same as those for fire return intervals. More growing season fires also occurred in JP (33.1%) and JP-WF (17.5%) than in RF-WWP (1.1%) forests. A dramatic decline in fire frequency occurred in all forests after 1905. Conclusions Changes in forest structure and composition occurred in both mid- and upper montane forests due to twentieth-century fire exclusion. Forest density increased in JP and JP-WF forests and white fir increased in JP-WF forests and is now replacing Jeffrey pine. Forest density only increased in some RF-WWP stands, but not others. Resource managers restoring fire to these now denser forests need to burn larger areas if fire is going to play its pre-settlement role in montane forest dynamics. [source] Noninvasive bioengineering assessment of the skin barrier function in patients with chronic venous insufficiencyBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2010I. Angelova-Fischer Summary Background Chronic venous insufficiency (CVI) comprises all symptoms caused by permanent venous and capillary hypertension. While the clinical manifestations of the disease have been well characterized, there is little knowledge on the skin barrier function in the affected patients. Objectives The aim of the study was to assess noninvasively the barrier function in patients with CVI stage C2 and stage C4 according to the CEAP classification in comparison with healthy controls (stage C0). Methods Thirty patients with CVI without concomitant diseases and 15 healthy, aged-matched controls were recruited for the study. The skin barrier function was assessed by measuring transepidermal water loss (TEWL), capacitance and skin colour symmetrically on the calf, medial and lateral malleolus, posterior arch (arcus venosus) and volar forearm. Results Compared with the forearm, there was a tendency for increased TEWL and significant reduction of capacitance on all measurement sites on the lower limb. Compared with the control group, the patients with CVI had significantly higher TEWL values on all measurement sites on the lower extremities while no difference in capacitance between patients and controls was observed. Conclusions Changes in the epidermal barrier function in patients with CVI are readily detectable by bioengineering methods as early as stage C2 and are manifested by significantly increased TEWL. Our results suggest that the reduced stratum corneum hydration in patients with CVI is due to anatomical differences rather than venous disease. These findings may help better understand the factors contributing to disease progression and its complications. [source] | ||||||||||