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The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created.

It was suggested in a recent article that sunspots drive decadal variation in Amazon River flow. This conclusion was based on a novel time series decomposition method used to extract a decadal signal from the Amazon River record. We have extended this analysis back in time, using a new hydrological proxy record of tree ring oxygen isotopes (δ18OTR). Consistent with the findings of Antico and Torres, we find a positive correlation between sunspots and the decadal δ18OTRcycle from 1903 to 2012 (r= 0.60, p< 0.001). However, the relationship does not persist into the preceding century and even becomes weakly negative (r= −0.30, p= 0.11, 1799–1902). This result casts considerable doubt over the mechanism by which sunspots are purported to influence Amazon hydrology. In a recent paper, researchers identified a possible connection between the amount of water flowing in the Amazon River and changes in solar activity, measured by number of sunspots. However, the precise details of this relationship and how it might work were not fully understood, and the analysis only covered the 20th century. Amazon tree rings (the annual growth bands visible in the wood of many temperate and tropical trees) have been shown to record information about basin rainfall (and hence Amazon River flow), in the year of their formation, and therefore offer a way to extend the hydrological record back in time. In this study, we used a new tree ring data set from Ecuador to test the link between sunspots and the Amazon water cycle over a 200 year period. We show that the relationship between sunspots and Amazon River flow is not constant over time and suggest it might even arise by chance, just as the hands of a broken clock point to the right time twice a day. This work highlights how proxy climate data sets can sometimes provide more insights than instrumental climate data alone. A new proxy record for Amazon River discharge is used to assess the influence of sunspots on Amazon hydrology over a 200 year periodThe direction of the relationship between sunspots and the hydrological proxy changes over time, casting doubt on the mechanism of controlThis work shows that long, annually resolved δ18OTRproxy records can provide more insights than instrumental data alone

The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998–2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen‐carbon interactions. Increase in FF aerosol emission over East Asia contributes substantially to regional increase in plant carbon uptakeThe global impact is small since increases in FF aerosols and NPP in East Asia were canceled by opposing trends in Europe and North AmericaThus, the increase in FF aerosols over East Asia may not act as a mechanism that would explain coincident increase in land carbon sink

Background/Purpose:A report in the literature suggests longer duration and greater intensity of late phase UVB erythema in older people. The aim of this study was to identify differences in minimum erythema dose (MED) and intensity of UV‐induced erythema after narrow band UVB exposure between older and younger individuals in the late phase of UVB erythema.

A 650 cm core from a Swiss bog represents 12,370 14C years of peat accumulation and provides the first complete record of atmospheric Pb deposition for the entire Holocene. Excess, non-atmospheric Sr in the peat was calculated by normalizing Sr/Sc to crustal abundance; this was used to differentiate between the ombrogenicsection of the bog in which inorganic solids are supplied exclusively by atmospheric deposition and the minerogeniczone where mineral-water interactions contribute metals to the peat. While sediment dissolution contributes significantly to the Sr inventory of the minerogenic section of the peat profile, there is no measurable effect of this process on the Pb burden. Isotopic analyses (204Pb, 206Pb, 207Pb, 208Pb) show that effectively all of the Pb in the peat profile was supplied exclusively from the atmosphere.

The Pantanal region of Brazil is the largest seasonally flooded tropical grassland and, according to local chamber measurements, a substantial CH4source. CH4emissions from wetlands have recently become of heightened interest because global atmospheric 13CH4data indicate they may contribute to the resumption of atmospheric CH4growth since 2007. We have regularly measured vertical atmospheric profiles for 2 years in the center of the Pantanal with the objectives to obtain an estimate of CH4emissions using an atmospheric approach, and provide information about flux seasonality and its relation to controlling factors. Boundary layer‐free troposphere differences observed in the Pantanal are large compared to other wetlands. Total emissions based on a planetary boundary layer budgeting technique are 2.0–2.8 TgCH4yr−1(maximum flux ∼0.4 gCH4m−2d−1) while those based on a Bayesian inversion using an atmospheric transport model are ∼3.3 TgCH4yr−1. Compared to recent estimates for Amazonia (∼41 ± 3 TgCH4yr−1,maximum flux ∼0.3 gCH4m−2d−1) these emissions are not that large. Our Pantanal data suggest a clear flux seasonality with CH4being released in large amounts just after water levels begin to rise again after minimum levels have been reached. CH4emissions decline substantially once the maximum water level has been reached. While predictions with prognostic wetland CH4emission models agree well with the magnitude of the fluxes, they disagree with the phasing. Our approach shows promise for detecting and understanding longer‐term trends in CH4emissions and the potential for future wetlands CH4emissions climate feedbacks. CH4emissions contribute substantially to greenhouse warming and atmospheric concentrations continue to grow rapidly. Increases in emissions from wetlands may contribute. We have measured regularly vertical CH4concentration profiles over the Pantanal, the largest tropical seasonally flooded grasslands, to provide an estimate of these emissions and to determine seasonal cycle. Our estimates are similar to earlier estimates based on direct flux measurements on the ground. Fluxes vary strongly seasonally. They are largest during the rise of water levels and decrease before maximum levels have been reached. Our data show that longer‐term vertical profile measurements could provide an answer whether wetland emissions are changing. Large CH4boundary layer‐free troposphere differences over Pantanal wetlands revealed by vertical atmospheric CH4profile dataAccording to atmospheric data, CH4flux is large during the early expansion phase of the inundated area and weakens at peak extentPrognostic global wetlands CH4emission models have limited skill regarding seasonality of Pantanal emissions Large CH4boundary layer‐free troposphere differences over Pantanal wetlands revealed by vertical atmospheric CH4profile data According to atmospheric data, CH4flux is large during the early expansion phase of the inundated area and weakens at peak extent Prognostic global wetlands CH4emission models have limited skill regarding seasonality of Pantanal emissions

Background:Literature reports indicate that phospholipid liposomes facilitate the accumulation of active agents in the infundibulum. Objective:The study hypothesis of an improved antibacterial efficacy of benzoyl peroxide (BPO) in phospholipid liposomes was tested in comparison with a commercial and a pharmacopoeial BPO preparation. Methods:The infundibular bacterial samples were obtained with the Permabond technique from 20 acne patients who had been treated with the test substances (vehicle-controlled) for 2 weeks twice per day in a single-blinded, comparative study on the upper back. Results:A significant antibacterial effect in the infundibula (Propionibacteria and Micrococcaceae, both: p < 0.001) for a BPO phospholipid liposome formulation could be demonstrated. In comparison to the other significantly efficacious BPO formulations which were also tested (commercial product and pharmacopoeial formulation), the BPO phospholipid liposome formulation showed a significantly greater antibacterial efficacy for Propionibacteria and Micrococcaceae (both: p < 0.01). Conclusion:A BPO formulation in phospholipid liposomes may represent an improvement of the conventional external BPO treatment of acne.

Two new UV lamps were investigated with respect to their antibacterial effectiveness in vitro.Propioni (n=20 strains) and Micrococcaceae (n=16 strains) bacteria extracted from acne patients were applied to RCM and sheep blood agar plates and irradiated with a narrow‐band UVB lamp (TL 100W/10R) at a wavelength of 313 nm and a UVA1 lamp (TL 01) at a wavelength of 345–440 nm. The precisely defined energy levels were, in the case of narrow‐band UVB, 0.00, 0.30, 0.50, 1.00, 2.00 and 3.00 J/cm2and, in the case of UVA1, 0.00, 2.50, 5.00, 7.50, 10.00 and 20.00 J/cm2. UVA1 inhibited neither the growth of Propioni nor Micrococcaceae bacteria. In contrast, the growth of Micrococcaceae was inhibited already at a dosage of 0.30 J/cm2of narrow‐band UVB (P<0.05), highly significant from 0.50 J/cm2(P<0.01) and to a maximum of 2.2 powers of 10 at 3.00 J/cm2compared with non‐radiated control plates. Propioni bacteria were significantly inhibited at the minimum dosage of 0.30 J/cm2of narrow‐band UVB (P<0.01) and to a maximum of 2.8 powers of 10 at 3.00 J/cm2.

Heat loss by radiation and conduction and oxygen release were measured on full thickness skin autografts in 46 guinea pigs on the seventh postoperative day. Using the same animals, the amount of hair on the graft was determined 3 months after surgery. This was assessed primarily as a measure of the extent of damage to hair follicles in the primary postoperative phase. Heat loss by conduction and oxygen release were also measured on the grafts and on symmetrically opposite control sites at this time. These measurements were used primarily as a measure of congestive hyperaemia in the subepidermal vascular plexus. Finally, the extent of changes in the collagen fibres was determined by histological examination. The author was unable to demonstrate any correlation between the circulatory picture on the seventh postoperative day and primary or secondary follicular damage. These results indicate that other, unknown factors have an important bearing on hair growth in grafts. These investigations also show that on the seventh postoperative day the reactivation of the pre-existing vascular system can be assessed mainly by heat loss by conduction and revascularization by new inward growth of vessels can be assessed mainly by the loss of radiant heat.

Studies on vascular morphology, histology, and thermometric experiments were performed on free full-thickness skin autografts in guinea pigs. 3 months after surgery partial alteration of the collagen fibers and lack of elastic fibers are evident. Analysis of vascular morphology in the affected regions reveals hyperemia in the subepidermal plexus; thermometric studies indicate that it is congestive. This congestive hyperemia also affects the perifollicular vascular network. Moreover, the arrangement of the vessels is occasionally irregular. This abnormal circulation might explain the accelerated synchronized hair growth cycles on full thickness skin autografts described by us elsewhere. It is also a conceivable cause of the acanthosis-like epidermal changes in the regions with altered fibers which we have described here.

The hair root pattern in full-thickness skin autografts in guinea pigs was evaluated on the basis of findings in a total of 34 grafts. Between the 4th and 12th day after surgery the proportion of anagen hairs was found elevated and increasing in all cases. Thus spontaneous loss of hair was not preceded by transformation of anagen hairs into telogen hairs. New hair growth did not occur until 3 to 4 weeks after surgery, and was succeeded by several accelerated synchronous hair growth cycles. This is interpreted as a result of secondary hypoxic damage to the hair follicles due to congestive hyperemia in the subepidermal vascular plexus, as described elsewhere.

Light sensitivity of the skin was tested in 15 male and 10 female patients, in which a squamous cell skin cancer had been proven histologically at least once, and in 25 healthy controls of the same age and sex. A Xenon lamp with different qualities of light was used. An analysis was also made of the sum of the skin surface lipids by direct extraction and gravimetrical measurement, together with an analysis of the composition of the lipids by thin layer chromatography. The back was used as the test area as it is a region not affected by the tumour and apart from that it is less exposed to light.

A lipid-free preparation containing 0.076% dexamethasone-21-sodium-m-sulfobenzoate (corresponding to 0.05% dexamethasone) has been applied to the right side of the back and the same vehicle without the agent to the left side of the back of 16 male subjects without any skin diseases. The applications were made twice daily over a period of 26 days. Two days after the final application the skin surface lipids were analysed quantitatively by means of the direct extraction method and the paper absorption method. Thin layer chromatographical analyses were also carried out. The sum of skin surface lipids is not altered by dexamethasone-21-sodium-m-sulfobenzoate. This agent does, however, induce a significant increase in the free fatty acids at the expense of the triglycerides. The importance of this result is discussed with reference to the pathogenesis of steroid acne.

A total of 375 anaerobic and microaerophilic coryneform rods, isolated from the pilosebaceous ducts of 26 healthy persons (71 strains) and from comedones (93 strains), pustules (107 strains), and the unaffected skin (104 strains) of 36 acne patients were classified according to the species key in Bergey's manual, the biotyping scheme of Pulverer and Ko, the serotyping schedule of Höffler et al., and the phage typing schedule of Jong et al. The statistical evaluation demonstrated certain differences in the frequencies of the Propionibacterium species and types between the different groups tested. Thus, the species P. granulosum was isolated only from acne patients (50.0% of patients examined) and was found more frequently in comedones and pustules than in unaffected follicles in acne patients. The majority of P. granulosum strains belonged to serotype II (95). Biotype A propionibacteria were more feequently found in strains from healthy controls (52.1% of strains) than in strains from comedones (17.2%), pustules (27.1%) and unaffected skin (38.5%) of the acne patients. The results of phagetyping showed that the P. acnes lysotype I was more frequent in acne patients (total: 73.2% of strains), especially in the inflamed pustules (88.5%), than in healthy controls (55.1%).

The cell kinetics of the sebaceous gland of the hamster ear were analysed in untreated animals, in animals treated with cyproterone acetate, and in animals treated with estradiol. Both active substances lead to a reduction in the size of the sebaceous gland (measurement with the integration plate), to a reduction of mitoses (colcemide method), to a reduction in the 3H-thymidine labelling index, to a prolongation of the S-phase (double labelling technique with 3H-thymidine which remain in contact with the basal lamina of the sebaceous gland 6 days after application of the isotope. The results indicate that, like cyproterone acetate, estradiol reduces the effect of androgens on cell kinetics in the sebaceous gland under the test conditions chosen, even if in an entirely different way.

The composition of the aerobic and anaerobic bacterial skin flora was investigated quantitatively and qualitatively in 25 patients with seborrheic eczema (SE) and in 35 healthy persons. In SE patients, the geometric mean count for propionibacteria in the pilosebaceous ducts of the forehead was reduced to a statistically significant extent in comparison with the control group. There was the same tendency with regard to the geometric mean count of the superficial anaerobic bacterial flora of the back, whereas the geometric mean counts of the coagulase-negative staphylococci were the same in the two groups. These results may explain earlier findings of a reduction of free fatty acids in the surface lipids in SE patients. According to the results of differentiation in 295 propionibacteria and 157 micrococcaceae, 7 biotypes and 10 phage types of propionibacteria which were so far unknown could be demonstrated. Significant differences between the groups with regard to the frequency of different biotypes, serotypes, and phage types could be demonstrated neither in propionibacteria nor in coagulase-negative staphylococci. The results of typing, however, showed that patients with SE displayed much more frequently several different propionibacterial species and types as well as several different micrococcal species and types than persons with healthy skin.

The amount of paraffins in the skin surface lipids has been determined in 10 test persons highly exposed to fumes and in 10 less exposed to fumes. The same investigation has been carried out in 10 other persons following a wet weather period as well as following a dry weather period. Results show that the paraffin content in high fume exposure and in dry weather is significantly greater than in reduced fume exposure and wet weather. From quantitative evaluation of the findings it seems probable that the greater amount of paraffins detected on the skin are precipitated from polluted air.

The thymidine labelling index and the mitosis rate (blocked by colcemid) in the basal cell layer of the guinea pig were determined before and during treatment with 5-fluorouracil (1 mg i.p. in 2 day's interval/100 g body weight). Additionally, the epidermal area and thickness and the number and size of cells were measured. 5-Fluorouracil equally reduces the thymidine labelling index and the mitosis rate with the full effect after treatment of at least 22 days. From these findings it is concluded that the S-phase — calculated from the end of the thymidine synthesis — is not altered. Furthermore atrophy of the epidermis runs parallel with the reduction of the 3H thymidine labelling index and the mitosis rate.

In 24 persons with a severe inflammatory acne and 48 control subjects, bacteria were sampled from the sebaceous gland excretory ducts with the glass sampling head method according to Holland et al. After anaerobic culture bacterial counts were performed. The total numbers of P. acnes and the frequency of detection of P. granulosum were determined. The bacterial counts of P. acnes were almost idendical in the two collectives. P. granulosum was detected at a significantly higher frequence in the acne patients than in the control subjects. It can be assumed on the basis of the results that an increase in the bacterial counts of P. acnes is not to be regarded as a pathogenetic factor in the inflammatory acne of older patients. On the other hand, they suggest that P. granulosum may have an appreciable role in acne.

Determinations of the minimum inhibitory concentrations for various antimicrobial surfactants with reference to the bacteria P. acnes, P. granulosum, and St. epidermidis are reported. The results show that quaternary ammonium compounds can display minimum inhibitory concentrations corresponding to those of relevant antibiotics. With the especially effective substance fractionated dimethylcocobenzalkoniumchloride (ARQUAD DMMCD-B), it could be further shown that with in vivo application in 70% isopropanol or in an ethanol-containing film mask ointment suppression can be obtained of P. acnes, all propionibacteria added, and all pilosebaceous duct bacteria which can be cultured under anaerobic conditions. The studies may point out a way of replacing antibiotics in the antimicrobial therapy of acne by quaternary ammonium compounds.

Infrared-spectroscopic investigations of the water content of the stratum corneum after application of emulsions and wash solutions are reported. As a methodologic variation infrared spectroscopy is applied after stripping the skin to determine the hydration of various depths of the stratum corneum by ointments. Using soap as an example, a method of correcting the overlap effects between the ointment and skin spectrums is presented which expands the application possibilities of infrared spectroscopy. An o/w emulsion with plenty of water and a w/o emulsion containing less water produce to almost the same degree a hydration of the deeper layers of the stratum corneum which lasts for at least 40 min. The report in the literature that soap solutions produce a stronger hydration of the stratum corneum than surfactant solutions is not supported.

Infrared spectroscopic measurements of hydration of the stratum corneum before and after stripping the skin five and ten times with scotch tape are reported. Investigations on 64 healthy persons show that for individuals over 45 and under 15 years of age the range of the measurement values is strikingly larger than for persons in the age group 15–45 years of age. A small, but not significant reduction in the measurement values is found in females as compared to males. A comparison of the clinically unaffected skin of atopic dermatitis patients with the skin of normal persons points to an increase in the hydration of the stratum corneum of atopic dermatitis patients, which is especially evident in patients who show clinical evidence of “dry” and rough skin.

A preparation of dexamethasone 0.02% in Eutanol G (n octyldodecanol) was applied once daily for three weeks, to the right side of the forehead of 25 male healthy test subjects. Eutanol G without dexamethasone was applied in the same way to the left side of the forehead. Before and at the end of the treatment period bacteria were removed from the pilo-sebaceous ducts by the method of Holland et al. [8]. Bacteria that grew under anaerobic conditions were evaluated quantitatively. Dexamethasone induced a significant increase in P. acnes, in all Propionibacteria and in the total bacterial count. The importance of these findings is discussed in relation to the development of steroid acne.

Free cholesterol in lipids from the scalp and hair is predominantly a constituent of epidermal lipids. Therefore, a reduction in cholesterol content induced by a drug indicates a reduction in cell turnover in the epidermis. As, according to the literature, increased cell turnover in the epidermis results in formation of dandruff, a reduction in the proportion of cholesterol should indicate inhibition of the formation of dandruff. Conversely, an increase in free cholesterol should generally indicate a “keratolytic” effect. So unequivocal an interpretation has not so far been possible in persons with dandruff, as it was not known whether free cholesterol was increased or decreased. In addition, this interpretation was not possible after use of antimicrobial substances, as in vitro investigations had failed to exclude microbial esterification of cholesterol on the scalp. The present investigation has shown that correlation of free cholesterol level with cell turnover is permissible in patients with dandruff, even if antimicrobial drugs are being tested.

The findings described show that Candidaspecies can be found in the feces of approximately half a population of non‐selected test persons and in the mouths of approximately a third. Intestinal Candidacolonization was found in most of these persons after one feces examination, and in practically all of them after a second examination. 10 d of therapy with 400 mg natamycin per day in sugarcoated tablet form and 40 mg natamycin in the form of tablets for sucking produced a negative fungus test for the feces in only 20 % of the cases. Although a combination of this therapy with 3 x 10 mg butylscopolamine per day improved short‐term results significantly, the long‐term results were hardly influenced at all. Typifying results according to the Warnock method showed that we are dealing with recurrences in practically all cases and not with new infections. Minimal inhibition concentrations (MIC) of natamycin showed no marked changes as a consequence of the natamycin treatment. Bei etwa der Hälfte unausgewählter Versuchspersonen waren im Stuhl und bei etwa einem Drittel im Mund Candida‐Species nachweisbar. Die meisten Fälle intestinaler Candida‐Besiedlung wurden mit einer einzigen Stuhluntersuchung, nahezu alle mit zwei Untersuchungen erfaßt. Eine 10tägige Therapie mit 400 mg Natamycin/d in Drageeform und 40 mg Natamycin in Form von Lutschtabletten führte nach 2 Monaten bei nur 20 % der Fälle zu einem negativen Pilznachweis im Stuhl. Die Kombination der Therapie mit 3 x 10 mg Blutylscopolamin/d verbes‐serte zwar signifikant die Kurzzeitergebnisse, jedoch kaum die Langzeitergebnisse. Die Typisierung nach der Methode von Warnock zeigte, daß es sich fast durchwegs um Rezidive and nicht um Neuinfektionen handelte. Keine wesentliche Veränderung zeigte die MHK gegen Natamycin unter der Therapie.

Full-thickness skin grafts 7.6 cm2 in size, have been removed from symmetrical areas of the back in 12 male guinea pigs and transferred from one side to the other in the usual way. By filling the vascular system with ink the vessels were investigated in each of 3 of the animals on the 6th, the 11th, between the 25th and 32nd and between the 56th und 64th postoperative day. Thick histological sections (120 µ) were taken for examination.

The influence of a liposomal formulation of a ceramide/phospholipid mixture on the barrier function of the skin in atopic tests, in subjects with healthy skin, and after lipid extraction was tested. The transepidermal water loss and the stratum corneum hydration served as parameters for the evaluation of the influence of the ceramide/phospholipid‐mixture treatment on the barrier function. Additionally a barrier‐function test with nicotinic acid ester was performed after ceramide/phospholipid‐mixture application. Stabilizing effects on the barrier function after application of ceramide/phospholipid‐mixture were found only in atopic skin and after lipid extraction but not in healthy skin. The results lead us to expect positive effects of ceramide/phospholipid‐mixture only if barrier damage is present. On a teste l'influence d'une formulation aux liposomes d'un melange ceramide/phospholipide sur la fonction protectrice de la peau de personnes lors d'un test atopique, sur une peau saine, et apres extraction lipidique. On a utilise la perte d'eau transepidermique et l'hydratation de la couche cornee comme parametres d'evaluation de l'influence du traitement sur la fonction protectrice. On a en outre effectue apres application un test de la fonction protectrice avec un ester d'acide nicotinique. On a constate des effets stabilisateurs de la fonction protectrice apres application seulement sur peau atopique et apres extraction lipidique mais pas sur peau saine. Les resultats nous conduisent a esperer des effets positifs uniquement en cas d'alteration de la fonction protectrice de la peau.

This paper deals with two cases where particularly favourable growth of hair has been observed following free transplantation of hair-bearing full-thickness grafts after several months. measurements of skin temperature and heat-loss of these areas indicate that an optimum of blood supply is found after a period of three months. This series was compared with another one of 14 similar cases. The amount of blood supply of the grafts after several months appears to be the essential factor with respect to the permanently successful growth of hair in such grafts.

Free full thickness skin grafts were transplanted from one side to the other on symmetrical areas of the back in 36 guinea pigs. The grafts were secured on one side by the Raster sticking method (Gottlob) using butyl-2-cyanoacrylate and on the other side by the usual suture technique, together with a pressure bandage. Functional circulation measurements (skin temperature and heat dissipation) and morphological vessel representations (by the indian ink injection method) show that the grafts fixed by butyl-2-cyanoacrylate have a poorer revascularisation. Between the 8th and 13th day after the operation the grafts which had been glued were more liable to split. Finally the sticking method caused a greater shrinkage of the graft and had an unfavourable influence on the growth of hair on the graft.

Quantitative determination of the skin surface lipids was carried out in 25 patients with acne before and after treatment with tetracycline for 8 weeks. Determinations were performed immedeately and 2 h after defatting the skin surface. In addition, the lipids were analysed by thin-layer-chromatography. 13 patients received 1 g oxytetracycline per day for 8 days which was followed by a daily administration of 100 mg oxytetracycline for 7 weeks. In 12 patients 1 g oxytetracycline was administrated daily for 8 weeks.

In acne patients a significant increase of the lipid level and a quicker replacement of the skin surface lipids after defatting the skin is demonstrated. The more serious the clinical picture is, the more pronounced is the seborrhoea. Microthinlayer chromatographic investigations show, that in acne patients the triglycerid and squalen fractions are increased, while the cholesterol and paraffin fractions are decreased, compared with those of healthy persons. These changes are more pronounced in the more serious forms of the disease. In addition, there is also a significant decrease of the free fatty acid fraction in the serious forms. An increase of free fatty acids and wax esters, which was expectable because of seborrhoea, was not to be found in patients suffering from acne vulgaris.

The wax ester fraction of the skin surface lipids has been investigated by means of gas chromatography in five patients with acne vulgaris. The investigations were carried out before and after an 8 week oral administration of 1 g oxytetracycline per day. The assumption that the change of the fatty acid chain lenghts to lower values, which is found in patients with acne, could be influenced by this treatment, was not supported by our investigations.

The vascular system in experimental, free, full thickness skin autografts in guinea pigs was visualized by injecting Indian ink in the period between the 6th postoperative day and and eight weeks after the operation. Ideally, revascularization occurs by reactivation ofexisting vessels in the graft. Even reactivation of perifollicular vascular networks and the subepidermal vascular plexus is possible. If revascularization occurs through the growth ofnew vessels, for a long time the vascular arrangement is not the same as that in normal guinea pig skin. The epidermis usually shows acanthosis-like changes. Fast and effective revascularization minimizes the extent and duration of this change.

An analysis of skin surface lipids by means of thin layer chromatography was carried out in persons with seborrhoea sicca and seborrhoea oleosa. Cholesterol and free fatty acids were significantly higher whereas triglycerides and paraffines were significantly lower in persons with seborrhoea oleosa as compared to persons with seborrhoea sicca. The casual level of the skin surface lipids was nearly the same in both groups.

Using the osmium acid test and qualitative and quantitative determinations of the skin surface lipids in 51 test persons 2 h after defatting the skin with petrol ether it could be shown that the reaction of the sebaceous glands to defatting of the skin differs from case to case, from body area to body area and from gland to gland. The rapidity and extent of the lipid replacement depends not only on the number of secreting sebaceous glands, but also on the extent of secretion of the single gland. The greater the surface on which sebum spreads, the more wax esters and the less paraffins can be demonstrated in the skin surface lipids.

The quantity and composition of skin surface lipids have been determined in 30 subjects with contact allergy and in 30 healthy control subjects. The results clearly show that seborrhoeic subjects are not more prone to sensitization. It is not clear from these results whether sebostasis is a predisposing factor, however there are no great differences between sebostatic subjects and normal subjects as regards to predisposition to sensitization. Thin layer chromatographic studies show that there is significantly more squalene in the skin surface lipids of allergic subjects than in control subjects. Our studies also show that alkali-resistence is significantly reduced in sensitized subjects.

During the first months after surgery sweat tests were carried out in 12 full thickness skin autografts.

We report on size determinations repeatedly performed on 29 full thickness autografts in man. The average size of graft was reduced by about 31.7% in the first 2 months; 1 year after the transplantation the size was only 19.9% below the initial value. The initial considerable diminution and the subsequent slight enlargement of the graft were statistically confirmed. The diminution varied in each case; in some cases we even found a considerable increase compared to the starting value. The tension of the surrounding area and the vascularization of the graft bed are important for the difference in size of the graft.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.