Extent Of Potential Damage Research Articles

Short-term repeated human biopsy sampling contributes to changes in muscle morphology and higher outcome variability.

Changes in skeletal muscle are an important aspect of overall health. The collection of human muscle to study cellular and molecular processes for research requires a needle biopsy procedure which, in itself, can induce changes in the tissue. To investigate the effect of repeat tissue sampling, we collected skeletal muscle biopsy samples from vastus lateralis separated by 7 days. Cellular infiltrate, central nucleation, enlarged extracellular matrix, and rounding of muscle fibers were used as indices to define muscle damage, and we found that 16/26 samples (61.5%) revealed at least two of these symptoms in the secondary biopsy. The presence of damage influenced outcome measures usually obtained in human biopsies. Damaged muscle showed an increase in the number of small fibers even though average fiber and fiber type-specific cross-sectional area (CSA) were not different. This included higher numbers of embryonic myosin heavy chain-positive fibers (P = 0.001) as well as elevated satellite cell number (P = 0.02) in the damaged areas and higher variability in satellite cell count in the total area (P = 0.04). Collagen content was higher in damaged (P = 0.0003) as well as nondamaged areas (P = 0.05) of the muscle sections of the damaged compared with the nondamaged group. Myofibrillar protein and ribonucleic acid (RNA) fractional synthesis rates were not significantly different between the damaged compared with the nondamaged group. Results indicate that common outcomes as well as outcome variability in human muscle tissue are affected by previous biopsies. Therefore, the extent of potential damage should be assessed when performing repeated biopsies.NEW & NOTEWORTHY Indices of damage can be found in repeated biopsy samples of nonintervened control legs. Variables, directly and not directly related to muscle damage or regeneration, were compromised in second biopsy. There is a need to determine potential damage within muscle tissue when repeated muscle sampling is part of the study design. Muscle biopsy sampling may be a source of increased heterogeneity in human muscle data.

Colonization, Abundance, and Damage ofRaoiella indicaHirst on Cultivars ofMusaspp. at Tabasco, México

The red palm mite, Raoiella indica Hirst, is a pest recently introduced and propagating in the Neotropical region where the extent of potential damage to cultivars of Musa spp. is not well known. Three basal leaves of each young ‘Dwarf Giant’ banana (Musa AAA Cavendish), ‘Horn’ plantain (Musa AAB Plantain), and ‘Date’ banana (Musa AA Sucrier) were experimentally infested with 200 adult mites per leaf. As a check, three coconut palms (Cocos nucifera L.) of cultivars ‘Pacific Tall’, ‘Malayan Dwarf’, and the hybrid (‘Pacific Tall’ x ‘Malayan Dwarf’) were infested. The objective was to evaluate colonize and increase in abundance of the pest, as well as damage it can cause in the humid tropics of Mexico. After 4 months, the number of adult mites per infested leaf had increased 2.4 to 5.3 times on Musa spp. cultivars and 43.4 to 54.1 times on cultivars of C. nucifera. Similarly, the rates of eggs, larvae-nymphs, and adults on nearby leaves were less on Musa spp. than on C. nucifera. Mild damage was observed on ‘Horn’ plantain and ‘Date’ banana, moderate damage on ‘Dwarf Giant’ banana, and the coconut palms were severely damaged. The rainfall had a negative effect on colonization and development of R. indica. Torrential rain and prolonged drizzle during most of the year in the study area regulated R. indica in host plant in the region. Effect of weather on decrease in abundance as well as phytosanitary practices should be considered when managing the pest.

Filling the gaps: need for research on cell-specific xenobiotic metabolism in the skin

The removal and metabolism of organic molecules is apivotal body function, usually performed by phase I andphase II enzymes. While detoxification is beneficial andnecessary, at the same time, the metabolic intermediatesand breakdown products generated in the process can haveimmunogenic, cancerogenic or apoptogenic potential,which differs from the respective parental chemical.Whether and which adverse health effects ensue dependson the affected cell types and tissue. For instance, ifdamage caused by a chemical induces apoptosis, easilyregenerating tissues may cope better than slowly prolifer-ating or rare precursor cells. On the other hand, potentialextent of damage is conceivably dependent on the xeno-biotic metabolizing activity of cell types, which in turnmight be governed by exposure, that is, tissues with highexposure could be more competent in xenobiotic metabo-lism. There is, however, a surprising lack of research toidentify cell-specific xenobiotic metabolism. Research onthe molecular activity of xenobiotic metabolizing enzymes(XME) has traditionally a strong focus on the liver as themain metabolizing and detoxifying organ of the body. Theskin is less well studied, albeit it forms a major barrieragainst the environment (including the chemical environ-ment) and is a target of occupational, accidental andintended-use (i.e., cosmetics and pharmaceuticals) chemi-cal exposure. Risks of exposure are irritation, inflamma-tion, allergies and cancer. Conceivably, skin cells maypossess yet underestimated strategies to balance XME-mediated danger.In a recent paper, the team around Michael Girardi(Modi et al. 2012) presented the exciting finding that dif-ferential expression of phase I enzymes CYP4501A1 and1B1 in skin Langerhans cells versus keratinocytes leads togeneration of DNA-modifying metabolites from the car-cinogen 7,12-Dimethylbenz[a]anthracen (DMBA) in theskin and eventually non-melanoma skin cancer. Theyfound that skin Langerhans cells efficiently metabolizeDMBA to DMBA-3,4-diol which leads to oncogenic Hrasmutations. Mice lacking skin Langerhans cells had fewerskin tumours upon DMBA treatment. They conclude‘‘ Thus, tissue-associated dendritic cells can enhancechemical carcinogenesis via PAH metabolism, highlightingthe complex relation between immune cells and carcino-genesis.’’ While the paper of Girardi and colleagues looksat chemical-induced (DMBA-induced) cancer, it has alsoimportant implications for understanding skin physiologyand skin toxicology.Sun light, that is, its UV radiation component, is themost important stressor of skin (Fritsche et al. 2007) andhas long been known to be genotoxic and a major riskfactor in skin cancer (Narayanan et al. 2010). UV and UV-induced DNA damage are the primary cause not only formelanoma with increasing incidence and new casesworldwide every year (Little and Eide 2012), but also ofskin basal cell carcinoma, squamous cell carcinoma,Kaposi

Factors Affecting Outcomes on the TEN (SPL) Test in Adults with Hearing Loss

Recent work using the Threshold Equalizing Noise (TEN) test as a gold standard suggests that the presence of cochlear dead regions in persons with moderate-to-severe hearing loss may be quite common. In addition, previous data suggest that certain characteristics of hearing loss, such as severe-profound high-frequency hearing loss or steeply sloping configurations may be more commonly associated with positive TEN findings. These findings, however, are based largely on studies including a relatively small number of participants and/or participants that were included based on specific audiometric criteria (e.g., the presence of severe high-frequency hearing loss). Likewise, results from many of these studies are limited to the frequency regions of 500-4000 Hz. There has been less work that has systematically evaluated the relationship between audiometric characteristics and TEN test findings, particularly in the frequency regions above 4000 Hz, on a large number of individuals with a wide range of hearing losses and hearing loss configurations. The purpose of this study was to further examine the effects of audiometric characteristics such as degree and slope of hearing loss on the rate of positive, negative, and inconclusive findings on the TEN test over a wide frequency range (250-8000 Hz). Given that the functional impact of positive findings (i.e., findings suggestive of a dead region) may vary with the extent of potential damage, we were also interested in determining the relative occurrence of "patchy" versus contiguous positive findings on the TEN. Fifty-nine adults (117 ears) with a wide range of SNHL participated. To examine results over a wide frequency range (250-8000 Hz), the TEN (SPL), rather than the TEN (HL), was utilized. Thresholds, in both ears, were measured in quiet and in the TEN (SPL). Results were categorized as positive (suggestive of a dead region), negative (not suggestive of a dead region), or inconclusive. Consistent with past research, positive TEN (SPL) results were more common when hearing losses exceeded 60 dB HL; however, there was not a systematic increase in positive results with increases in threshold. In contrast to previous work, however, positive test results among individuals with milder hearing losses (< 60 dB HL) were not uncommon, suggesting a potential for false positive results. In regard to audiometric slope, also consistent with past research, slope of hearing loss was an inadequate predictor of TEN (SPL) results. Negative results (not suggestive of a dead region) were less common in participants with steeply sloping losses while positive test findings were unaffected by hearing loss slope. Although a large proportion of participants had positive results on the TEN (SPL), for most participants, these positive findings occurred in isolated (i.e., one or two frequencies) rather than in contiguous frequency regions. The relatively large number of inconclusive results and the potential for false positive results makes interpreting the functional impact of TEN (SPL) results difficult, particularly when positive results are in the high (> 4000 Hz) frequencies. In addition, although a large proportion (84%) of study participants had positive findings on the TEN (SPL), the functional impact of these findings is not clear as, in the majority of cases, positive findings occurred at only one or two test frequencies.

Rescue archaeology in eastern Cameroon

Many infrastructural development projects are now being carried out in Cameroon (e.g. road building, oil pipeline construction, and urban renewal). At present, no specific data base exists to determine the current and potential extent of damage to archaeological and historical sites. To redress this, we believe that there is an urgent need to make impact assessments and mitigation work a mandatory precondition of development approval for entrepreneurs and public works professionals operating in the country.

Determining the most informative scenarios of environmental impact from potential major accidents

In many situations where an agency is aware of potential disasters, it is necessary to analyse in some depth, possible disaster scenarios. The reason for analysing a scenario is similar to analysing in depth any example—it forces a precision and is likely to bring to mind aspects not realized when thinking in general terms. The example scenarios are also likely to form the basis for data collection, to «put some numbers» on the extent of potential damage and the probability of that damage. Furthermore, a scenario, like any example, serves as a basis of understanding and communication of the projected risks. Unfortunately the effort dedicated to developing and analysing a number of scenarios can be great, and such expenditure may not be justified. What one seeks is to identify one, or at most a few, potential accidents whose analysis gives maximum information about the total accident risk in many or all of its aspects, without demanding an excessive budget to develop and analyse a large number of scenarios. The paper considers probability, damage and similarity as appropriate bases for selecting those accidents on which can be built scenarios that are not only important in their own right, but will also give information about the results of other possible accidents. An integer linear program is formulated, with the objective of maximizing the similarity between the selected candidate accident(s) and all identified potential accidents. This is found to be computationally simple to solve with modern software. The approach is demonstrated by applying it to define a «most informative» scenario of a major liquid spill in an inland waterway.

Assessing the Potential Extent of Damage to Inland Lakes in Eastern Canada due to Acidic Deposition. IV. Uncertainty Analysis of a Regional Model

In this paper, we consider the significance of uncertainty in inputs to the regional surface water acidification model of Marmorek et al. (1990. Can. J. Fish. Aquat. Sci. 47: 55–66). Monte Carlo methods are used to propagate input uncertainty through to measures of uncertainty in the model's overall predictions. We consider four key inputs which represent primary areas of input uncertainty: acidic sulphate deposition (Da), original lake sulphate concentrations ([SO4]0), a watershed neutralization parameter (FW), and an in-lake neutralization parameter (SS). The analysis is repeated for secondary watersheds from north-central Ontario, the Quebec Laurentians, and insular Newfoundland. Uncertainty in Daand [SO4]0consistently overwhelms the effect of uncertainty in FWand SSon overall model uncertainty. The relative importance of Dadecreases as one moves east from the high-deposition regions of central Ontario. We discuss the implications of our results for priority setting for future acidification research and monitoring.