Fibroblast-mediated contraction in actinically exposed and actinically protected aging skin

The changes in skin morphology over time are a consequence of both chronologic aging and the accumulation of environmental exposure. Through observation, we know that actinic radiation intensifies the apparent aging of skin. We have investigated the effects of aging and actinic radiation on the ability of fibroblasts to contract collagen-fibroblast lattices. Preauricular and postauricular skin samples were obtained from eight patients aged 49 to 74 undergoing rhytidectomy. The samples were kept separate, and the fibroblasts were grown in culture. Lattices constructed with preauricular fibroblasts consistently contracted more than lattices containing postauricular fibroblasts. The difference in amount of contraction in 7 days between sites was greatest for the younger patients and decreased linearly as donor age increased (r = -0.96). This difference may be due to preauricular fibroblasts losing their ability to contract a lattice as aging skin is exposed to more actinic radiation.     

Karyometric analysis of actinic damage in unexposed and sun-exposed skin and in actinic keratoses in untreated individuals

OBJECTIVE: To assess the ability of karyometric analysis to demonstrate progression of actinic damage as a function of sun exposure in individuals with actinic keratoses (AKs) and to evaluate the stability of that assessment over a 3-month period. STUDY DESIGN: Biopsies from subjects with AKs were obtained from unexposed skin, sun-exposed skin and AK lesions. Subjects used an SPF 50 sunscreen, and 3 months later additional biopsies were taken from sun-exposed and AK sites. A total of 13,300 nuclei were recorded from 31 subjects. RESULTS: Measures of nuclear abnormality (NA) and effects of sun damage based on discriminant function (DF) scores were derived. Actinic damage levels varied significantly across biopsy site, demonstrating the method's sensitivity. Accrual of actinic damage was demonstrated in sun-exposed skin and AK lesions when all nuclei were examined over 3 months but only for sun-exposed skin when the worst-damaged nuclei were examined. This suggests a ceiling effect of nuclear damage in the progression to abnormality. Within-subject variability was similar for both NA and DF when all nuclei were considered. Among the worst-damaged nuclei (as defined by high DF), DF showed lower within-case variability than NA, perhaps due to a reduction in nuclear heterogeneity. CONCLUSION: Karyometry's ability to detect subtle levels of actinic damage in nuclear chromatin patterns may make it useful in screening agents for possible use in cancer chemoprevention.     

Actinic skin damage and mortality--the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study

Background

Exposure to sunlight may decrease the risk of several diseases through the synthesis of vitamin D, whereas solar radiation is the main cause of some skin and eye diseases. However, to the best of our knowledge, the association of sun-induced skin damage with mortality remains unknown.

Methodology/Principal Findings

Subjects were 8472 white participants aged 25–74 years in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Cardiovascular disease mortality, cancer mortality, and all-cause mortality were obtained by either a death certificate or a proxy interview, or both. Actinic skin damage was examined and recorded by the presence and severity (absent, minimal, moderate, or severe) of overall actinic skin damage and its components (i.e., fine telangiectasia, solar elastosis, and actinic keratoses). Cox regression and Kaplan-Meier methods were applied to explore the associations. A total of 672 cancer deaths, 1500 cardiovascular disease deaths, and 2969 deaths from all causes were documented through the follow-up between 1971 and 1992. After controlling for potential confounding variables, severe overall actinic skin damage was associated with a 45% higher risk for all-cause mortality (95% CI: 1.22, 1.72; P<0.001), moderate overall skin damage with a 20% higher risk (95% CI: 1.08., 1.32; P<0.001), and minimal overall skin damage with no significant mortality difference, when compared to those with no skin damage. Similar results were obtained for all-cause mortality with fine telangiectasia, solar elastosis, and actinic keratoses. The results were similar for cancer and cardiovascular disease mortality.

Conclusions

The present study gives an indication of an association of actinic skin damage with cardiovascular disease, cancer and all-cause mortality in white subjects. Given the lack of support in the scientific literature and potential unmeasured confounding factors, this finding should be interpreted with caution. More independent studies are needed before any practical recommendations can be made.     

Human polymerase α inhibitors for skin tumors. Part 2. Modeling,synthesis and influence on normal and transformed keratinocytes of new thymidine and purine derivatives

Recently, the three-dimensional structure of the active site of human DNA polymerase α (pol α) was proposed based on the application of molecular modeling methods and molecular dynamic simulations. The modeled structure of the enzyme was used for docking selective inhibitors (nucleotide analogs and the non-nucleoside inhibitor aphidicolin) in its active site in order to design new drugs for actinic keratosis and squamous cell carcinoma (SCC). The resulting complexes explained the geometrical and physicochemical interactions of the inhibitors with the amino acid residues involved in binding to the catalytic site, and offered insight into the experimentally derived binding data. The proposed structures were synthesized and tested in vitro for their influence on human keratinocytes and relevant tumor cell lines. Effects were compared to aphidicolin which inhibits pol α in a non-competitive manner, as well as to diclofenac and 5-fluorouracil, both approved for therapy of actinic keratosis. Here we describe three new nucleoside analogs inhibiting keratinocyte proliferation by inhibiting DNA synthesis and inducing apoptosis and necrosis. Thus, the combination of modeling studies and in vitro tests should allow the derivation of new drug candidates for the therapy of skin tumors, given that the agents are not relevant substrates of nucleotide transporters expressed by skin cancer cells. Kinases for nucleoside activation were detected, too, corresponding with the observed effects of nucleoside analogs.     

An artifact in measurements of in vivo light-induced absorbance changes

The effects of scattered actinic radiation on photomultipliers (Hamamatsu R-562) were investigated. Using cotton-wool to model dense biological preparations, it was found that the scattered actinic radiation received by the photomultiplier gives rise to phytochrome-like signals. This demonstrated the necessity to shield the photomultiplier from scattered actinic light for sensitive measurements with light-scattering preparations.     

Karyometry of nuclei from actinic keratosis and squamous cell cancer of the skin

OBJECTIVE: To use karyometric analysis methods to compare actinic keratoses (AKs) to squamous cell carcinomas (SCCs) to determine if SCCs showed a logical progression beyond that seen in AKs and to explore variability within and between lesion types to better understand distinctions between the 2. STUDY DESIGN: Biopsies from 31 subjects with AKs were obtained from upper inner arm skin, forearm skin and AK lesions. Biopsies from 23 different subjects in a related subproject provided SCC biopsies for comparison. RESULTS: Karyometric measures of nuclear abnormality and sun damage were derived. Mean actinic damage levels progressed logically from inner arm to sun-exposed skin, to AK, to SCC. Considerable heterogeneity existed at the case level. Unsupervised learning methods revealed 2 distinct clusters of progressed lesions with different nuclear signatures, reflecting differing levels of actinic damage. Number of AKs and SCCs and invasiveness and differentiation of SCCs were distributed across both clusters in roughly equivalent proportions. CONCLUSION: Karyometric methods, shown previously to be capable of sensitively detecting subtle nuclear changes, revealed the possibility of 2 progression pathways, each containing AKs and SCCs. This finding may have prognostic implications.     

Liquid nitrogen for the treatment of actinic keratosis: A longitudinal assessment

Cryosurgery with liquid nitrogen is one of the most used treatments for actinic keratosis. We aimed to study the effectiveness of two consecutive sessions of cryosurgery for actinic keratosis and investigate factors associated with its therapeutic success. Hence, we conducted a longitudinal study including 92 patients of both sexes, aged 50–75 years with 5–50 actinic keratosis on the face and forearms, who underwent cryosurgery and treatment with sunscreen SPF 30, at baseline and after 120 days. The lesions were counted in duplicate by the same examiner before the start of treatment and after 120 (N = 92) and 300 days (N = 33), represented by their medians and quartiles and compared using the generalized linear mixed effects model (negative binomial). Treatment behavior was investigated in relation to sex, age, education, skin type, smoking, sun exposure at work and the use of aspirin, anti-inflammatory and angiotensin-converting enzyme inhibitors. There was a significant reduction in the actinic keratosis count on the face and forearms (p < 0.05). Our results confirmed the effectiveness of cryosurgery for actinic keratosis, with a 57% reduction in the number, and size of the lesions. Higher education levels (p = 0.02) and less sun exposure at work (p = 0.02) independently promoted a significant reduction in the actinic keratosis count. Different population groups showed characteristic responses to the treatment, which may be explained by the degree of adherence to the use of photoprotection. In two sessions, cryosurgery with liquid nitrogen reduced the actinic keratosis count.     

Comparative histochemical study of Bowen's disease and actinic keratosis: preserved normal basal cells in Bowen's disease

The degree of DNA-instability as revealed by immunohistochemical staining with anti-cytidine antibody after acid hydrolysis (DNA-instability test) has been recently used as a marker of malignancy. This technique was applied to examine 17 skin tissue samples of Bowen's disease, 47 of actinic keratosis, 15 of squamous cell carcinoma, 5 of seborrheic keratosis, and 10 of normal skin. All benign neoplastic cells of seborrheic keratosis and normal epidermal cells were negative. On the other hand, all cancer cells were positive with the DNA-instability test, indicating their malignancy, but all basal cells in Bowen's disease were completely negative. Compatible with this result, the basal cells in Bowen's disease were characteristically normal as evident in other histochemical examinations. Thus, they were negative with p53 immunohistochemistry, with normal signals of chromosome 17 in situ hybridisation and argyrophilic nucleolar organiser region, and showed slightly enhanced proliferative activity as revealed by proliferating cell nuclear antigen immunohistochemistry. Immunohistochemical staining with 34 beta E12 (monoclonal antibody against cytokeratins 1, 5, 10, and 14), which stains all normal epidermal keratinocytes including basal cells, showed that only the basal cells of Bowen's disease stained strongly and homogeneously, while all cancer cells in the upper layers of Bowen's disease and all layers of actinic keratosis were only sporadically or weakly stained. Staining with 34 beta B4 (monoclonal antibody against cytokeratin 1), which recognises the whole epidermis except for the basal layer in the normal epidermis, showed that the basal cells in the Bowen's disease were completely negative, and lower layer cells in the actinic keratosis and upper layer cells in Bowen's disease were only sporadically stained positive, although the superficial layer cells in actinic keratosis stained strongly and homogeneously. Our findings clearly indicate that the basal cells in Bowen's disease are normal. In support of this conclusion, the same cells showed normal morphology on electron microscopy with preserved basement membrane, although the latter was often damaged in actinic keratosis.     

The chlorophyll fluorescence quenching and changes of absorbance in pea chloroplasts

Chlorophyll (Chl) fluorescence quenching parameters were measured in dark-adapted pea leaves and chloroplasts with the purpose to find the conditions of high and low non-photochemical quenching, that would be stable during a prolonged irradiation. A PAM fluorometer was used for measuring induction curves in the range of actinic radiation of 3-35 W m-2, with an ordinary value of about 15 W m-2. The effects of various mediators, i.e., ascorbate, methyl viologen (MV), dithiothreitol (DTT) and nigericin, on the quenching process were tested. Simultaneously, the absorbance was measured during a 15-20 min period of irradiation and after the actinic radiation was turned off, i.e., in the recovery period. The pH values of chloroplast suspensions were 5.5, 6.5 and 8.0, the largest non-photochemical quenching was observed at pH of 6.5. The irradiation of chloroplasts led to an absorption decrease within the entire photosynthetically active range, attaining saturation when the fluorescence reached Fs level, and to an absorption increase during the recovery period. Absorbance changes at the maximum of red band were 10-20 %. A decrease in Chl concentration (10 %) after irradiation was found only at pH of 5.5, when the recovery time was the longest, i.e., about 60 min.     

The chlorophyll fluorescence quenching and changes of absorbance in pea chloroplasts

Chlorophyll (Chl) fluorescence quenching parameters were measured in dark-adapted pea leaves and chloroplasts with the purpose to find the conditions of high and low non-photochemical quenching, that would be stable during a prolonged irradiation. A PAM fluorometer was used for measuring induction curves in the range of actinic radiation of 3-35 W m-2, with an ordinary value of about 15 W m-2. The effects of various mediators, i.e., ascorbate, methyl viologen (MV), dithiothreitol (DTT) and nigericin, on the quenching process were tested. Simultaneously, the absorbance was measured during a 15-20 min period of irradiation and after the actinic radiation was turned off, i.e., in the recovery period. The pH values of chloroplast suspensions were 5.5, 6.5 and 8.0, the largest non-photochemical quenching was observed at pH of 6.5. The irradiation of chloroplasts led to an absorption decrease within the entire photosynthetically active range, attaining saturation when the fluorescence reached Fs level, and to an absorption increase during the recovery period. Absorbance changes at the maximum of red band were 10-20 %. A decrease in Chl concentration (10 %) after irradiation was found only at pH of 5.5, when the recovery time was the longest, i.e., about 60 min. This revised version was published online in June 2006 with corrections to the Cover Date.     

Impact of Aging Time on the Dermal Penetration of Phenol in Soil

Phenol is released to soil through accidental spills, manufacturing processes, and waste disposal. With time, chemicals can become more sequestered in soil (aging). Since skin is the body's primary route of entry for phenol, the impact of aging time on the dermal penetration of phenol was assessed in Atsion and Keyport soils. In vitro studies were conducted on dermatomed male pig skin using a flow-through diffusion cell methodology and radiolabeled phenol. After 3 and 6 months of aging in the Atsion soil, dermal penetration decreased from 84% of the initial dose for pure phenol (without soil) to 15% and 8%, respectively, while the dermal penetration of phenol aged in the Keyport soil was reduced to 22% and 17%, respectively. Atsion soil has a higher organic matter content (4.4%) than Keyport soil (1.6%) suggesting that the lower bioavailability of phenol aged in the Atsion soil may be due to the amount of organic matter in that soil. Although the data indicate that the potential health risk from dermal exposure to phenol would be lower after aging in soil than to pure chemical, further experiments are warranted at lower soil loads and with additional concentrations of phenol to quantify the risk.     

Quantitative and qualitative effects of chemical peeling on photo-aged skin: an experimental study

Chemical peel reverses the visible stigmata of photo aging in human skin. The qualitative and, in particular, the quantitative changes in the dermis that effect this transformation are unclear. This study used a recognized photo-aged animal model, the Skh:HR-1 hairless mouse, to quantify and qualify the changes that occurred in collagen and glycosaminoglycan content after chemical peel. One hundred Skh:HR-1 hairless mice were photo-aged by use of chronic ultraviolet B irradiation for 14 weeks. After irradiation the animals were randomly distributed into five groups of 20 mice each: group 1, control; group 2, 50% glycolic acid peel; group 3, 30% trichloroacetic acid peel; group 4, 50% trichloroacetic acid peel; group 5, phenol peel (Baker-Gordon formula). The respective peeling agent was applied to the dorsal skin of each animal while it was fully anesthetized. Punch biopsies were taken at several times after peel for histological and biochemical analysis. Glycosaminoglycan content was assessed at 14, 28, and 60 days using a colorimetric assay. Collagen content per unit volume increased initially 3 days after the procedure in all chemical peel groups, declining on day 7, and peaking again on day 28. Significant elevations (p < 0.04) were seen in the 30% trichloroacetic acid, 50% trichloroacetic acid, and phenol peels on days 3 and 28 in comparison with controls. This increase in collagen content was not maintained and returned to control values by 60 days. Glycosaminoglycan content per unit volume was elevated initially after peel with significant elevation (p < 0.02) in the 50% trichloroacetic acid and phenol groups on days 14 and 28. This increase in glycosaminoglycan content was not maintained beyond 28 days and declined to control values by day 60 in all groups. Histological examination demonstrated an increase in dermal thickness in the 50% trichloroacetic acid and phenol groups in comparison with controls by day 60. Under polarized light all chemical peel groups at day 60 demonstrated a reorganization of collagen in the reticular and papillary dermis. The elastotic masses that are pathognomonic of photo aging were present in the control group but were absent in the peel groups and demonstrated a reorganization of the elastic fibers in the dermis. This effect was deeper in the dermis in the deeper peel groups (50% trichloroacetic acid and phenol peel). The beneficial effects of chemical peel were due to a combination of two findings; a reorganization in dermal structural elements and an increase in dermal volume. These effects were more pronounced in the deeper peel groups.     

A Possible Regulation of Ethylene Production by the Epidermis in Mung Bean Hypocotyl Sections

IAA-induced and l-aminocyclopropane-l-carboxylic acid (ACC)-dependentethylene production in etiolated mung bean (Vigna radiata [L]Wilczek) hypocotyl sections does not occur in epidermal cells(Todaka and Imaseki 1985). Mung bean hypocotyls contain a proteinwhich inhibits auxin-induced ethylene biosynthesis in hypocotylsections (Sakai and Imaseki 1975a, b). This inhibitory proteinwas also found to inhibit ACC-dependent ethylene productionin hypocotyl sections, but not in hypocotyl sections from whichthe epidermis had been removed. Uptake of ACC by both unpeeledand peeled sections was not inhibited by the protein. Similarly,IAA-induced ethylene production was inhibited by the proteinin unpeeled hypocotyl sections, but not in peeled sections.The protein was not inactivated in peeled sections, as proteinsynthesis by peeled sections was inhibited to the same extentas in unpeeled sections. The protein inhibited incorporationof 3,4-[¹⁴C]-methionine into ACC and ethylene in unpeeled sections,but not in peeled sections, whereas oxidation of the labeledmethionine into CO₂ was inhibited by the protein to a similarextent in both types of hypocotyl sections. KCN, a potent inhibitorof ethylene production, inhibited both IAA-induced and ACC-dependentethylene production in both peeled and unpeeled hypocotyl sections.It is likely that the epidermis plays some role in controllingethylene production which occurs in stem cells other than epidermalcells. (Received July 16, 1985; Accepted October 21, 1985)     

Automated Detection of Actinic Keratoses in Clinical Photographs

Background

Clinical diagnosis of actinic keratosis is known to have intra- and inter-observer variability, and there is currently no non-invasive and objective measure to diagnose these lesions.

Objective

The aim of this pilot study was to determine if automatically detecting and circumscribing actinic keratoses in clinical photographs is feasible.

Methods

Photographs of the face and dorsal forearms were acquired in 20 volunteers from two groups: the first with at least on actinic keratosis present on the face and each arm, the second with no actinic keratoses. The photographs were automatically analysed using colour space transforms and morphological features to detect erythema. The automated output was compared with a senior consultant dermatologist’s assessment of the photographs, including the intra-observer variability. Performance was assessed by the correlation between total lesions detected by automated method and dermatologist, and whether the individual lesions detected were in the same location as the dermatologist identified lesions. Additionally, the ability to limit false positives was assessed by automatic assessment of the photographs from the no actinic keratosis group in comparison to the high actinic keratosis group.

Results

The correlation between the automatic and dermatologist counts was 0.62 on the face and 0.51 on the arms, compared to the dermatologist’s intra-observer variation of 0.83 and 0.93 for the same. Sensitivity of automatic detection was 39.5% on the face, 53.1% on the arms. Positive predictive values were 13.9% on the face and 39.8% on the arms. Significantly more lesions (p<0.0001) were detected in the high actinic keratosis group compared to the no actinic keratosis group.

Conclusions

The proposed method was inferior to assessment by the dermatologist in terms of sensitivity and positive predictive value. However, this pilot study used only a single simple feature and was still able to achieve sensitivity of detection of 53.1% on the arms.This suggests that image analysis is a feasible avenue of investigation for overcoming variability in clinical assessment. Future studies should focus on more sophisticated features to improve sensitivity for actinic keratoses without erythema and limit false positives associated with the anatomical structures on the face.     

不同颜色果袋对‘云红梨2号’果皮色泽形成的影响

研究了不同颜色果袋对‘云红梨2号’果实着色的影响,比较了不同套袋处理下果皮外观着色、叶绿素、类黄酮、总酚、花色素苷含量以及花色素苷合成相关酶活性的差异.结果表明: 发育期的黑暗处理有利于解袋后梨果皮着色;不同套袋处理中,采前解袋自然光照射下梨果皮中花色素苷含量最高,着色最好,白色纸袋次之.不同套袋处理显著影响果皮中叶绿素、类黄酮、总酚和花色素苷含量,从而影响梨果皮的外观色泽.不同套袋处理的花色素苷合成酶活性差异显著;相关性分析表明,果皮中花色素苷含量与二氢黄酮醇-4-还原酶(DFR)和类黄酮3-O-葡萄糖基转移酶(UFGT)活性呈显著正相关,而与苯丙氨酸解氨酶(PAL)活性相关性不显著.     

Shifts of bacteriochlorophyll and carotenoid absorption bands linked to cytochrome c-555 photooxidation in Chromatium

Shifts in the absorption bands of bacteriochlorophyll and carotenoids in Chromatium vinosum chromatophores were measured after short actinic flashes, under various conditions. The amplitude of the bacteriochlorophyll band shift correlated well with the amount of cytochrome c-555 that was oxidized by P₈₇₀⁺ after a flash. No bacteriochlorophyll band shift appeared to accompany the photooxidation of P₈₇₀ itself, nor the oxidation of cytochrome c-552 by P₈₇₀⁺. The carotenoid band shift also correlated with cytochrome c-555 photooxidation, although a comparatively small carotenoid shift did occur at high redox potentials that permitted only P₈₇₀ oxidation.

The results explain earlier observations on infrared absorbance changes that had suggested the existence of two different photochemical systems in Chromatium. A single photochemical system accounts for all of the absorbance changes.

Previous work has shown that the photooxidations of P₈₇₀ and cytochrome c-555 cause similar changes in the electrical charge on the chromatophore membrane. The specific association of the band shifts with cytochrome c-555 photooxidation therefore argues against interpretations of the band shifts based on a light-induced membrane potential.     

Reliability and validity of a histologic score as a marker for skin cancer chemoprevention studies

OBJECTIVE: To develop a reliable and valid scoring system for grading skin biopsies from actinic keratosis (AK) and sun-damaged skin for use in evaluating the efficacy of skin cancer chemopreventive agents. STUDY DESIGN: A panel of dermatopathologists developed histologic criteria and diagnostic definitions for the progression of lesions from early AK to AK. The criteria were then applied to a sample of 335 histologic slides from an ongoing chemoprevention study. A 10% sample of 35 slides was reread in order to assess intrarater reliability. RESULTS: Six of the 7 criteria demonstrated high reliability (> 85%). The total histologic score, calculated using the 6 criteria, was found to significantly differentiate between (blinded) biopsy location (normal, pre-AK, AK and adjacent to squamous cell carcinoma) and histologic diagnosis (normal, pre- or early AK, AK and squamous cell carcinoma). CONCLUSION: The total histologic score, having demonstrated reliability on repeated readings and validity in its association with biopsy location and histologic score, is a reliable and valid end point for judging the efficacy of agents in skin cancer chemoprevention studies. Additional interrater reliability tests utilizing larger test sets and a rigorous statistical design should be undertaken to establish its portability.     

Effect of phosphatidylglycerol on conformation and micro-environment of tyrosyl residue in photosystem II

The structural aspects in the interaction of phosphatidylglycerol (PG) with photosystem II (PSIl), mainly the effect of PQ on conformation and microenvironment of tyrosine residues of PSIl proteins were studied by Fourier transform infrared (FTIR) spectroscopy. It was found that the binding of PG to PSIl particle induces changes in the conformation and micropolarity of phenol ring in the tyrosine residues. In other words, the PG effect on the PSIl results in blue shift of the stretch vibrational band in the phenol ring from 1620 to 1500 cm-1 with the enhancement of the absorb-ance intensity. Additionally, a new spectrum of hydrogen bond was also observed. The results imply that the hydrogen-bond formation between the OH group of phenol and one of PG might cause changes in the structures of tyrosine residues in PSIl proteins.     

Fourier transform infrared spectroscopy as a metabolite fingerprinting tool for monitoring the phenotypic changes in complex bacterial communities capable of degrading phenol

The coking process produces great volumes of wastewater contaminated with pollutants such as cyanides, sulfides and phenolics. Chemical and physical remediation of this wastewater removes the majority of these pollutants; however, these processes do not remove phenol and thiocyanate. The removal of these compounds has been effected during bioremediation with activated sludge containing a complex microbial community. In this investigation we acquired activated sludge from an industrial bioreactor capable of degrading phenol. The sludge was incubated in our laboratory and monitored for its ability to degrade phenol over a 48 h period. Multiple samples were taken across the time‐course and analysed by Fourier transform infrared (FT‐IR) spectroscopy. FT‐IR was used as a whole‐organism fingerprinting approach to monitor biochemical changes in the bacterial cells during the degradation of phenol. We also investigated the ability of the activated sludge to degrade phenol following extended periods (2–131 days) of storage in the absence of phenol. A reduction was observed in the ability of the microbial community to degrade phenol and this was accompanied by a detectable biochemical change in the FT‐IR fingerprint related to cellular phenotype of the microbial community. In the absence of phenol a decrease in thiocyanate vibrations was observed, reflecting the ability of these communities to degrade this substrate. Actively degrading communities showed an additional new band in their FT‐IR spectra that could be attributed to phenol degradation products from the ortho‐ and meta‐cleavage of the aromatic ring. This study demonstrates that FT‐IR spectroscopy when combined with chemometric analysis is a very powerful high throughput screening approach for assessing the metabolic capability of complex microbial communities.     

Congenital dislocation of the hip

In surgical skin planing steel wire brushes have been largely replaced by the less hazardous diamond chip burs or "fraises" and serrated steel wheels. In addition to acne pits and wrinkling, multiple actinic (senile) keratoses are an important indication for planing. Planing provides a nonscarring method for the treatment of existing keratoses, as well as a prophylaxis against skin cancer by replacing the sun-damaged, precancerous epidermis with new epidermal cells derived from the cutaneous adnexa (pilosebaceous and sweat gland units). There are clinical landmarks indicating the depth of planing which can serve as a guide to the operator and can be correlated with microscopic findings. The results of experiments on the comparative effects of refrigerants on animal and human skin indicate that human facial skin can tolerate considerable freezing with ethyl chloride or dichlorotetrafluoroethane (Freon 114) but that mixtures containing large proportions of the much colder dichlorodifluoromethane (Freon 12) may be undesirable. Refreezing an area of the skin in order to perform a more adequate planing is not considered hazardous.THE REGENERATION OF THE SKIN FOLLOWING PLANING HAS THREE COMPONENTS: Epidermal, adnexal and dermal. The cells of the epidermis and the adnexa are equipotential. A knowledge of the anatomy of the acne pit enables the operator to decide which pits can be benefited by planing and which should be excised before planing. The successful treatment of acne pits of the face by planing in patients having keloids elsewhere on the body is reported.