Blue Light Radiation Research Articles

Ultraviolet-B Phototoxicity and Hypothetical Photomelanomagenesis: Intraocular and Crystalline Lens Photoprotection

Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Optical radiation measurement, analysis, and perspective. Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Crystalline lens UV-B retinal protection is deficient in children and young adults, increasing their potential susceptibility to acute retinal phototoxicity and hypothetical photomelanomagenesis. UV-B radiation has sufficient energy/photon to induce primary melanomagenic DNA lesions, unlike blue light or UV-A radiation. UV-blocking and blue-blocking IOLs have negligible UV-B transmittance. UV-transmitting IOL transmittance of UV-B radiation is equivalent to that of a 15-year-old crystalline lens. If optical radiation exposure is responsible for welders' increased risk of uveal melanoma, then UV-B radiation is the most probable causative agent and spectacle wear is a potential confounding factor in epidemiologic studies of ocular melanoma. Welders under 30 years of age are at greater risk for welding maculopathy than older welders. Children, adults under 30 years of age, and pseudophakic individuals with UV-transmitting IOLs should wear sunglasses in bright environments because of the UV-B window in their crystalline lenses or IOLs.

A Novel and Low-Cost Disposable Device for Phototherapy of Neonatal Jaundice

AbstractThe present work details, to our knowledge, the first examination of the influence of blue-light radiation on the optical properties of organic luminescent films in attempting to develop an indicator dosimeter for phototherapy of neonatal jaundice. Jaundice is the most common problem encountered in newborns due to immature functioning in the liver. The operating principle of the device is based on the optical response of poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene (MEH-PPV) and tris(8-hydroxyquinolinato) aluminum (Alq3) materials dispersed in polystyrene (PS) matrix (denoted as PS/MEH-PPV/Alq3). It is observed a blue-shift on the photoluminescence of PS/MEH-PPV/Alq3 system from red to orange-yellow, and then to green as function of the blue-light radiation exposure time. The result is attributed to the spectral overlap between emission of Alq3 and absorption of MEH-PPV. The optical response of PS/MEH-PPV/Alq3 to radiation was investigated to design a low-cost (< US$ 0.05) “smart” sensor to represent easily the radiation dosage normally used in blue-light phototherapy. The basic idea behind this concept considers the sensor as a traffic light device, where red represents underdose and green the prescription dose or overdose, while orange-yellow suggests that radiation therapy is an ongoing process. This personal real-time radiation dosimeter appears here as a key requirement for successful development of innovations in effective management of the radiation dose planning before treatment of neonatal where control of dose absorption of infants is extremely important.

The direct synthesis of mesoporous structuredMnO2/TiO2 nanocomposite: a novel visible-light active photocatalyst with large pore size

A series of visible-light-driven mesoporous structuredMnO2/TiO2 nanocrystal photocatalysts have been synthesized through a modified sol–gel method, and theN2 adsorption–desorption isotherm confirms that the mesoporous materials possess large poresize (up to 9.2 nm) and a narrow pore size distribution. X-ray powder diffraction(XRD) analyses and complementary x-ray photoelectron spectroscopy (XPS)measurements reveal that the doping of the transition metal Mn inhibits the growth ofTiO2 anatase nanocrystals and the Mn species are highly dispersed on the surface ofTiO2. The ultraviolet (UV)–vis spectrum demonstrates the excellent adsorption properties ofMnO2/TiO2 over the whole region of visible light, which enables this novel photocatalysis material topossess remarkable activity in the photocatalytic degradation of methylene blue undervisible light radiation. Moreover, a ‘coating mechanism’ based on the nucleation of titaniananocrystals along with the interaction between the dopant precursors and titania clustershas been suggested.

Melatonin in Glycyrrhiza uralensis: response of plant roots to spectral quality of light and UV‐B radiation

Melatonin (N-acetyl-5-methoxytryptamine) is known to be synthesized and secreted by the pineal gland in vertebrates. Evidence for the occurrence of melatonin in the roots of Glycyrrhiza uralensis plants and the response of this plant to the spectral quality of light including red, blue and white light (control) and UV-B radiation (280-315 nm) for the synthesis of melatonin were investigated. Melatonin was extracted and quantified in seed, root, leaf and stem tissues and results revealed that the root tissues contained the highest concentration of melatonin; melatonin concentrations also increased with plant development. After 3 months of growth under red, blue and white fluorescent lamps, the melatonin concentrations were highest in red light exposed plants and varied depending on the wavelength of light spectrum in the following order red >> blue > or = white light. Interestingly, in a more mature plant (6 months) melatonin concentration was increased considerably; the increments in concentration were X4, X5 and X3 in 6-month-old red, blue and white light exposed (control) plants, respectively. The difference in melatonin concentrations between blue and white light exposed (control) plants was not significant. The concentration of melatonin quantified in the root tissues was highest in the plants exposed to high intensity UV-B radiation for 3 days followed by low intensity UV-B radiation for 15 days. The reduction of melatonin under longer periods of UV-B exposure indicates that melatonin synthesis may be related to the integrated (intensity and duration) value of UV-B irradiation. Melatonin in G. uralensis plant is presumably for protection against oxidative damage caused as a response to UV irradiation.

A novel approach of LED light radiation improves the antioxidant activity of pea seedlings

Influence of light-emitting diode (LED) light on antioxidant activity of radiated pea seedlings was first studied using red (625–630 nm) and blue (465–470 nm) LED lights as light sources in an attempt to determine and compare the changes in chlorophyll and β-carotene contents, and Trolox equivalent antioxidant capacity (TEAC, μM). After radiation for 96 h, comparing to white light group, red light radiated seedlings displayed significant ( p < 0.05) increases in stem length and leaf area, while blue light radiation significantly ( p < 0.05) increased the stem length and seedling weight. Chlorophyll in leaves increased rapidly when seedlings were radiated by blue light but no significant ( p > 0.05) difference was observed among light radiated seedlings after 96-h cultivation. β-Carotene content of LED radiated leaves was significantly ( p < 0.05) higher in red light (54.47 ± 2.35 μg/g) group than in the others. TEAC value of ethanol and acetone extracts (50 mg/mL) of 240 pieces of red light radiated seedlings cultured for 96 h reached 106.48 and 81.68 μM, respectively, were higher than the other treatments. In conclusion, the contribution of red light to significant β-carotene expression and antioxidant activity for nutrition and health benefits and blue light to seedling weight and chlorophyll induction of radiated pea seedlings are emphasized.

UV-A Induces Two Calcium Waves in Physcomitrella patens

Our understanding of the role of Ca2+ in blue/UV-A photoreceptor signaling in a single cell is limited. Insight into calcium signaling has now been attained in Physcomitrella patens and its cryptochrome and phototropin knock-outs. Physcomitrella patens caulonemal filaments grow in the dark by apical extension and their apical cells are highly polarized. Fura-2-dextran ratio images of the apical cell from wild type (WT), Ppcry1a/1b and PpphotA2/B1/B2 were obtained immediately following UV-A exposure (30 microW cm(-2) at 340 nm for 1,000 ms plus 30 microW cm(-2) at 380 nm for 1,000 ms) [abbreviated as 1,000 ms (340/380 nm)] and demonstrated two intracellular waves: a Ca2+ wave from the growing apical tip through the apical cap, and a wave from the junction of the neighboring cell through the vacuolar, nuclear and plastid regions. In WT, the UV-A-induced tip wave increase had a magnitude of 454.0 +/- 40 nM, traveled at a rate of 3.4 +/- 0.7 microm s(-1) and was complete within 26.6 +/- 2.3 s, while the basal vacuolar wave had a magnitude of 596.8 +/- 110 nM, a rate of 8.4 +/- 0.8 microm s(-1) and duration of 25.3 +/- 4.9 s. Subsequent Ca2+ spikes of similar magnitude followed these waves. The amplitude of the Ca2+ waves in the apical cap and basal vacuolar regions of Ppcry1a/1b were higher than those in the WT, while the duration of those in PpphotA2/B1/B2 was longer. Subsequent Ca2+ spikes occurred in WT and Ppcry1a/1b but not in PpphotA2/B1/B2. When Mn2+ was added to the culture medium, the [Ca2+](cyt) increase was delayed, did not move as a wave and lasted longer. The results indicate that plants respond to blue light and UV-A radiation by generating a wave of changes in the [Ca2+](cyt). The characteristics of these Ca2+ waves were dependent upon cryptochrome and phototropin. Blue/UV-A signaling in P. patens appears to differ from that in Arabidopsis.

Effect of blue light radiation on growth of aspergillus sojae

Effect of blue light radiation on growth of aspergillus sojae

The Effect of UV and Visible Lightirradiation on the Development of Microsclerotium of the Fungus Macrophomina Phaseolina

Macrophomina phaseolina is a poliphagus fungus, which is able to infect numerous host-plants (maize, sunflower, pepper,) and causes large yield losses. Our in vitro experiments demonstrate, how different wavelength light irradiation influences the growth of mycelium and the formation of microsclerotium. The habit of cultures treated by blue light and UV radiation changed, the formed microslerotia had a convenient sharpness for the data evaluation by CCD camera. The mycelium was degraded as a result of UV radiation.

麹菌への光照射効果

麹菌への光照射効果

Calculation of spectral weighting functions for the solar photobleaching ofchromophoric dissolved organic matter in temperate lakes

The effect of solar radiation on the dissolved absorption coefficient (λCDOM[λ]), which reflects the concentration of chromophoric dissolved organic matter (CDOM), was investigated in several lakes near Bariloche, Argentina and in northeastern Pennsylvania, USA. Samples of 0.2 µm filtered lake water were exposed in quartz tubes to different portions of the solar spectrum using optical cutoff filters to remove parts of the ultraviolet (UV) region of the solar spectrum. Changes in the spectral absorption in these samples and the absorbed incident energy were used to calculate spectral weighting functions (SWFs) for the photobleaching (PB) of CDOM. PB was measured as the loss of αCDOM[λ] (the αCDOM[λ] was averaged from 280 to 500 nm) per unit absorbed energy. CDOM from humic and clear lakes, as well as from a Sphagnum bog and an algal culture, was used in the experiments covering a wide range of carbon sources. We used an iterative, nonlinear optimization method to fit the measured results to a simple exponential function in order to generate each SWF. Comparing individual SWFs calculated for various CDOM sources, we computed a summary SWF from the experiments using epilimnial CDOM from our study lakes. Our summary SWF was able to explain 80‐90% of the observed variance in our exposure experiments, and we were able to predict PB results obtained for other Argentine lakes (mean error 14.5%). Finally, we calculated that the effect of UV‐B radiation on PB was small (&lt;20% of total decrease in the absorption coefficient) compared to UVA and blue light radiation. This suggested that increased UV‐B radiation due to stratospheric ozone depletion would not greatly increase the photobleaching of whole water column CDOM in Patagonian lakes (&lt;10%).

LIGHT EFFECTS ON ORNAMENTAL MICROPLANT SHOOTS AND BULBS QUALITY

The quality of micropropagated ornamental bulbous and cormous plants (Freesia sp., Hyacinthus sp., Lilium sp., Cyclamen sp.) under the influence of varying light regimes (blue, green, yellow, red, far-red, white, UV irradiation and darkness) was studied in long term cultures. Red and yellow light promoted ernbryogenic callus formation and proliferatior as well as somatic embryo maturation regardless of genotypes. Blue light and ultraviolet radiation stimulated development of somatic embryos but inhibited maturation of somatic embryos (Freesia, Hyacinthus and Cyclamen), The number of adventitious bulbs (Hyacinthus) or corms (Freesia) was highest when explants were irradiated with red light or cultured in darkness. The bulbs formed in these conditions were mature and well developed. They consisted of scales exclusively, Blue light as well as UV irradiation resulted in smaller bulbs that were less numerous and their outer scales formed leaf shaped structures (Hyacinthus). However, blue and green lights had a positive effect on the number of adventitious buds and fresh weight of adventitious shoots (Freesia, Hyacinthus, Cyclamen) as well as formation of adventitious bulbs in Lilium sp. As far as the level of pigments is concerned, it was observed that blue light enhanced the total amount of anthocyanins while both blue light and UV irradiation promoted the production of chlorophyll a and b.

Light-induced metastable states in nitrosyl–ruthenium complexes containing ethylenediamine and oxalate ion ligands

The metastable state which is produced by irradiation with the green-blue region of light was studied by IR and other spectroscopic techniques for solid states of newly synthesized nitrosyl–ruthenium complexes; cis-[Ru(Hox)(en)2NO]Cl2·EtOH, trans-[Ru(Hox)(en)2NO]Cl2, cis-K[Ru(ox)2(en)NO]·3H2O, cis-[Ru(Hox)(ox)(en)NO], and cis-K[Ru(ox)2(en)NO] [ox = (CO2)22−]. Continued irradiation at 77 K results in development of a photostationary state in the same way as for sodium nitroprusside. The population of the metastable state molecule in the photostationary state of each sample depends on the irradiation wavelength and reaches a maximum at 441.6 nm which is the shortest wavelength in the present study. A broad absorption band with an absorbance maximum at ≈600 nm is observed for the metastable state of a trans-[Ru(Hox)(en)2NO]Cl2 single crystal. The short wavelength tail of the band is considered to be involved in the photostationary equilibrium under blue light radiation. The metastable state molecules decay to the ground state at temperatures considerably higher than the two metastable molecules (MS1 and MS2) of sodium nitroprusside. The decay temperature of trans-[Ru(Hox)(en)2NO]Cl2, which is defined as the temperature at which the rate constants of the thermal decay becomes 10−3 s−1, is 277 K, which is the highest value reached among the metastable states of nitrosyl complexes reported so far. In the Raman spectra of trans-[Ru(Hox)(en)2NO]Cl2, the Ru-(NO) stretching vibrations are observed at 604 cm−1 and 476 cm−1 for the ground and metastable state molecules, respectively.

Day-long Alterations of the Photomorphogenic Light Environment Affect Young Watermelon Plant Growth: Implications for Use with Rowcovers

The sensitivity of watermelon [Citrullus lanatus (Thumb.) Matsum &amp; Naki `Sugar Baby'] plant growth to day-long alterations in light quality was determined by exposing plants to light transmitted through broad band wavelength selective filters. Of the three acetate filters analyzed (nos. 19, 27, and 74), filter no. 74 transmitted the least amount of photosynthetic photon flux (PPF) (400 to 700 nm), the smallest red light: far-red light ratio (R:FR) (645:735 nm), and the greatest amount of blue light (400 to 500 nm) radiation from metal halide lamps. Plants grown under filter no. 74 were taller, had elongated petioles, and had a greater amount of petiole and stem biomass than plants grown under the other filters. Spectral transmission properties of commercially available rowcover materials were evaluated for variation of PPF, R:FR, and blue light. Clear polyethylene rowcovers were completely permeable to all measured (330 to 850 nm) wavelengths of radiation from metal halide lamps. White polyethylene rowcovers were the least permeable of the rowcover materials to wavelengths of radiation with decreases in the PPF, R:FR, and blue light. Spunbonded polyester materials slightly reduced PPF, R:FR, and blue light. Plants grown under white polyethylene and spunbonded materials grew taller (longer stems) than plants grown under the clear polyethylene rowcover. Petiole lengths were generally longer for plants grown under white polyethylene. Our results suggests that alterations in the R:FR and blue light due to selected wavelength transmission through commercially available rowcover material alter early watermelon growth.

The effect of L-cysteine and N-acetylcysteine on porphyrin/heme biosynthetic pathway in cells treated with 5-aminolevulinic acid and exposed to radiation.

The effects of L-cysteine (LC) and N-acetylcysteine (NAC) on porphyrin accumulation in a human dermal microvascular endothelial cell line (HMEC-1) and a human epidermoid carcinoma cell line (A431) loaded with 5-aminolevulinic acid (ALA) and exposed to ultraviolet A (UVA) and blue light radiation were determined. Porphyrin accumulation was decreased in the presence of 0.1-7.5 mM LC (24.8%-31.4% suppression in HMEC-1 cell; 35.8%-48.9% suppression in A431 cells), and in the presence of 0.1-10.0 mM NAC (30.9%-58.0% suppression in HMEC-1 cells; 8.5%-45.3% in A431 cells). The suppression occurred in a LC or NAC dose-dependent fashion. The above was associated with partial reversal of suppression of ferrochelatase (FeC) activity in HMEC-1 cells and in A431 cells. As compared to FeC activity in cells treated with ALA and irradiation, enzyme activity was higher (by 31.9%-62.1%) in the presence of LC (1.0 mM or 5.0 mM) and in the presence of NAC (1.0 mM or 5.0 mM). These data indicate that LC and NAC have protective effects on porphyrin- and irradiation-induced diminution of FeC activity in HMEC-1 cells and A341 cells in vitro.

Rapid Fluence-Dependent Responses to Ultraviolet-B Radiation in Cucumber Leaves: The Role of UV-Absorbing Pigments in Damage Protection

Summary The role of foliar UV-absorbing pigments (UVAP) as optical screening agents in the resistance of Cucumis sativus L. to UV-B radiation was investigated by exposing young leaves at a defined developmental stage from sensitive (cv Poinsett) and insensitive (cv Ashley) lines to brief UV-B treatments varying between 4 and 10 h. The amount of blue light (BL) or UV-A radiation during UV-B exposure was also varied. Rapid increases in UVAP immediately following UV-B were compared to damage in the same tissue (increased specific leaf weight or chlorosis) determined 72 h after the start of UV-B. Poinsett was more sensitive to both forms of UV-B damage than Ashley under conditions where the response to UV-B was not saturated. Although UVAP increased rapidly in response to UV-B, it is unlikely that optical screening by these compounds was responsible for genetic differences in sensitivity to UV-B for the following reasons: 1) the kinetics of UVAP increase were similar to that for induction of damage; 2) increases in UVAP in the UV-sensitive line (Poinsett) were similar to those in the resistant line (Ashley); and 3) BL and UV-A radiation significantly reduced damage by UV-B in cv Poinsett when given simultaneously but had relatively small stimulatory effects on rapid UVAP accumulation. These results do not rule out a general role for optical screening by UVAP nor do they exclude the possibility that qualitative differences in UVAP (e.g., as antioxidants) are the basis for cultivar differences.

Intracellular pH changes induced in Propionibacterium acnes by UVA radiation and blue light

The intracellular pH changes in the Gram-positive skin bacterium Propionibacterium acnes by blue light and UVA radiation were studied. Two methods ( 31P nuclear magnetic resonance (NMR) spectroscopy and fluorescence spectroscopy using a pH-sensitive fluoroprobe (2′,7′-bis-(2-carboxyethyl)-5-(and-6-)-carboxyfluorescein)) were used to determine the intracellular pH. The pH changes induced by irradiation were found to be a function of cell survival. These changes as a function of cell survival followed the same pattern for blue light and UVA radiation. A reduction of the pH gradient across the cell membrane (inside alkaline) was found for lethal doses (less than 15% survival). This reduction corresponded to a decrease in intracellular pH and may indicate a proton influx. An increase in the pH gradient, which corresponded to an increase in the intracellular pH, was observed for sublethal doses. This increase appears to be reversible. Thus two separate mechanisms, which appear to be the same in UVA and blue light regions, may be responsible for the irradiation-induced pH alterations.

Rat lens glycolysis after in vivo exposure to narrow band UV or blue light radiation

UV radiation and short wavelength visible light are known to damage various tissues in the eye. This paper investigates the effect on rat lens glycolysis after in vivo exposure with 90 kJ m −2 narrow band UV radiation (UVB, 300 nm) and 90 kJ m −2 blue light (435 nm) radiation. After exposure, all lenses were incubated in Medium 199. Samples of culture medium were withdrawn after 2, 4, 6 h and 5, 10, 20 h in two UVB studies and after 5, 10 and 20 h in a blue light study. Lactate is the major end product of lens glycolysis. Lactate was determined with a modified enzymatic-photometric method. Intralenticular lactate was determined in one UVB experiment. In the UVB experiments we found a lower lactate production in the exposed lenses 2–6 h after exposure. There was an accumulation of lactate inside UVB-exposed lenses after 6 h incubation compared with their contralateral lenses. No significant effect on lactate production was observed in the blue light experiment. Conclusions. UVB induced a reversible inhibition of glycolysis. UVB also induced an accumulation of lactate inside the lens. Blue light tended to increase glycolysis.

Effect of UVA and blue light on porphyrin biosynthesis in epidermal cells.

To study porphyrin biosynthesis in normal human keratinocytes and A431 cells derived from human epidermoid carcinoma, cultured cells were incubated with delta-aminolevulinic acid (ALA), the precursor of porphyrin synthesis, and accumulation of porphyrins was measured spectrofluorometrically. Both human keratinocytes and A431 cells accumulated porphyrins in a time-dependent and a dose-dependent fashion. Protoporphyrin was the predominant porphyrin accumulated by both cell types. Porphyrin accumulation was enhanced by Ca Mg ethylenediaminetetraacetic acid, a ferrochelatase inhibitor, and the enhancement was reversed by the addition of iron, suggesting the utilization of iron by ferrochelatase. The effect of light on porphyrin accumulation was evaluated by exposing the ALA-loaded A431 cells to ultraviolet-A (UVA) and blue light radiation, followed by continued incubation with ALA for 2-48 h. There was an enhancement of porphyrin accumulation 2-48 h after the radiation as compared with nonirradiated controls. Consistent with this finding, ferrochelatase activity decreased in these cells at 24 h and 48 h. These data demonstrate that human keratinocytes and A431 cells are capable of porphyrin biosynthesis, and that exposure of porphyrin-containing A431 cells to light, which includes the Soret band spectrum, decreases the ferrochelatase activity, which is responsible, at least in part, for the further increase in porphyrin level.

Phytochrome-Mediated Phototropism in De-Etiolated Seedlings

Phototropic responses to broadband far red (FR) radiation were investigated in fully de-etiolated seedlings of a long-hypocotyl mutant (lh) of cucumber (Cucumis sativus L.), which is deficient in phytochrome-B, and its near isogenic wild type (WT). Continuous unilateral FR light provided against a background of white light induced negative curvatures (i.e. bending away from the FR light source) in hypocotyls of WT seedlings. This response was fluence-rate dependent and was absent in the lh mutant, even at very high fluence rates of FR. The phototropic effect of FR light on WT seedlings was triggered in the hypocotyls and occurred over a range of fluence rates in which FR was very effective in promoting hypocotyl elongation. FR light had no effect on elongation of lh-mutant hypocotyls. Seedlings grown in the field showed negative phototropic responses to the proximity of neighboring plants that absorbed blue (B) and red light and back-reflected FR radiation. The bending response was significantly larger in WT than in lh seedlings. Responses of WT and lh seedlings to lateral B light were very similar; however, elimination of the lateral B light gradients created by the proximity of plant neighbors abolished the negative curvature only in the case of lh seedlings. More than 40% of the total hypocotyl curvature induced in WT seedlings by the presence of neighboring plants was present after equilibrating the fluence rates of B light received by opposite sides of the hypocotyl. These results suggest that: (a) phytochrome functions as a phototropic sensor in de-etiolated plants, and (b) in patchy canopy environments, young seedlings actively project new leaves into light gaps via stem bending responses elicited by the B-absorbing photoreceptor(s) and phytochrome.

Lactate production in the crystalline lens after exposure to blue light radiation

La longueur du carpe et du tarse, des métacarpiens et des métatarsiens, des doigts et des orteils de 142 prosimiens a été mesurée. Le rapport en pourcentage a été établi pour chaque individu entre la longueur de chaque pièce osseuse et celle de son troisième métacarpien, afin d’éliminer les différences liées à la taille du reste du corps. Ce rapport a été comparé à celui de l’homme. Les variations caractérisées se sont manifestées au niveau des sous-familles.Le carpe présentait les mêmes valeurs que celle de l’homme à l’exception de celui des indris, qui était plus court. Le pouce avait proportionnellement tantôt la même longueur que celui de l’homme, même parfois un peu plus, tantôt une taille plus petite chez les eulémurs, les hapalidés, les mégalapidés, les indris, les daubentinés et les pérodictus. Les différents métacarpiens, y compris le quatrième, étaient un peu plus courts que le troisième. Dans ces sous-familles, le deuxième rayon était aussi souvent plus court et même beaucoup plus court chez les mégalapidés et les périodictus. Les autres rayons étaient un peu plus longs, en particulier le quatrième qui pouvait dépasser le troisième dans d’assez nombreuses sous-familles.La longueur du tarse était extrêmement variable. Elle était deux fois plus grande chez les galagoïdés, nettement plus grande chez les tarsius et discrètement chez les hapalidés, un peu plus petite chez les autres lémuriens et beaucoup plus petites chez les autres prosimiens, rejoignant en cela la quasi-totalité des simiens. L’hallux était proportionnellement aussi long que celui de l’homme et parfois même plus long. Les métatarsiens étaient tantôt un peu plus, tantôt moins long, mais toujours entre eux sensiblement de même longueur. Les autres orteils étaient courts chez l’aye-aye (daubentiné), dont le pied apparaissait encore plus petit que celui de l’homme. Les orteils des autres prosimiens ressemblaient beaucoup aux doigts et chez le propithécus et le pérodictus, le quatrième prenait des proportions gigantesques.Établissement d’une relation anatomique et fonctionnelle entre la longueur des trios derniers rayons des mains et des pieds des prosimiens et la biomécanique de leurs articulations trapézométacarpiennes et de leurs premières articulations cunéométacarpiennes.The length of the carpus and tarsus, the metacarpus and metatarsus, the fingers and toes of 142 prosimian apes was measured. The relationship expressed as a percentage was drawn up for each individual between the length of each osseous part and that of its third metacarpal in order to eliminate the differences related to the size of the rest of the body. This ratio was compared with that of man. The characteristic variations appeared at the level of the subfamilies.The carpus presented the same values as that of man except for that of the indris, which was shorter. The thumb had proportionally the same length as that of man, sometimes longer and sometimes smaller as in the Eulemurs, Hapalidea, Megalapidea, Indrises, Daubentonia and Perodictus. The different metacarpals, including the fourth, were a little shorter than the third. In these subfamilies, the second ray was also often shorter and even much shorter in the Megalapidea and the Perodictus. The other rays were a little longer, in particular the fourth which could exceed the third in rather many subfamilies.The length of the tarsus was extremely variable. It was twice larger in the Galagoidae, definitely larger in the tarsius and discreetly in the Hapalidae, a little smaller in the other Lemurs and much smaller in the other Prosimian apes, joining in that the near totality of the simians. The hallux was proportionally as long as that of man and sometimes even longer. The metatarsals were sometimes a little longer, sometimes less long, but always appreciably of the same length between them. The other toes were short at the aye aye (daubentonia), of which the foot appeared even smaller than that of man. The toes of the other prosimious resembled much to the fingers and in the propithecus and the perodictus, the fourth took gigantic proportions.There has been establishment of an anatomical relation and functional calculus between the length of the last three rays of the hands and the feet of prosimian apes and the biomechanics of their trapezometacarpal and their first cuneometacarpal joints.